Science.gov

Sample records for disease habitat suitability

  1. Biodiversity: Habitat Suitability

    EPA Science Inventory

    Habitat suitability quantifies the relationship between species and habitat, and is evaluated according to the species’ fitness (i.e. proportion of birth rate to death rate). Even though it might maximize evolutionary success, species are not always in habitat that optimizes fit...

  2. Habitat Suitability Information: Blacknose Dace

    USGS Publications Warehouse

    Trial, Joan G.; Stanley, Jon G.; Batcheller, Mary; Gebhart, Gary; Maughan, O. Eugene; Nelson, Patrick C.

    1983-01-01

    A review and synthesis of existing information were used to develop riverine and lacustrine habitat models for Blacknose dace, a freshwater species. The models are scaled to produce an index of habitat suitability between 0 (unsuitable habitat) to 1 (optimally suitable habitat) for freshwater, marine, and estuarine areas of the continental United States. Habitat suitability indexes (HSI's) are designed for use with the habitat evaluation procedures developed by the U.S. Fish and Wildlife Service. Also included are discussions of Suitability Index (SI) curves as used in the Instream Flow Incremental Methodology (IFIM) and SI curves available for an IFIM analysis of Blacknose dace.

  3. Habitat Suitability Index Models: Pronghorn

    USGS Publications Warehouse

    Allen, Arthur W.; Cook, John G.; Armbruster, Michael J.

    1984-01-01

    This is one of a series of publications that provide information on the habitat requirements of selected fish and wildlife species. Literature describing the relationship between habitat variables related to life requisites and habitat suitability for the pronghorn (Antilocapra americana) are synthesized. These data are subsequently used to develop Habitat Suitability Index (HSI) models. The HSI models are designed to provide information that can be used in impact assessment and habitat management.

  4. Habitat Suitability Index Models: Marten

    USGS Publications Warehouse

    Allen, Arthur W.

    1982-01-01

    Habitat preferences and species characteristics of the pine marten (Martes americana) are described in this publication. It is one of a series of Habitat Suitability Index (HSI) models and was developed through an analysis of available scientific data on the species-habitat requirements of the pine marten. Habitat use information is presented in a review of the literature, followed by the development of a HSI model. The model is presented in three formats: graphic, word and mathematical. Suitability index graphs quantify the species-habitat relationship. These data are then synthesized into a model which is designed to provide information for use in impact assessment and habitat management activities.

  5. Habitat Suitability Index Models: Muskellunge

    USGS Publications Warehouse

    Cook, Mark F.; Solomon, R. Charles

    1987-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the muskellunge (Esox masquinongy Mitchell). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  6. Habitat Suitability Index Models: Bobcat

    USGS Publications Warehouse

    Boyle, Katherine A.; Fendley, Timothy T.

    1987-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the bobcat (Felis rufus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  7. Habitat Suitability Index Models: Wood Duck

    USGS Publications Warehouse

    Sousa, Patrick J.; Farmer, Adrian H.

    1983-01-01

    A review and synthesis of existing information were used to develop models for breeding and wintering habitats for the wood duck (Aix sponsa). The models are scaled to produce indices of habitat suitability between 0 (unsuitable habitat) and 1 (optimally suitable habitat). Habitat suitability indices are designed for use with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  8. Habitat Suitability Index Models: Longnose Sucker

    USGS Publications Warehouse

    Edwards, Elizabeth A.

    1983-01-01

    A review and synthesis of existing information were used to develop riverine and lacustrine habitat models for Longnose sucker (Catostomus catostomus), a freshwater fish. The models are scaled to produce an index of habitat suitability between 0 (unsuitable habitat) to 1 (optimally suitable habitat) for freshwater areas of the continental United States. Habitat suitability indexes (HSI's) are designed for use with the habitat evaluation procedures developed by the U.S. Fish and Wildlife Service.

  9. Habitat Suitability Index Models: Bigmouth Buffalo

    USGS Publications Warehouse

    Edwards, Elizabeth A.

    1983-01-01

    A review and synthesis of existing information were used to develop riverine and lacustrine habitat models for Bigmouth buffalo (Ictiobus cyprinellus), a freshwater fish. The models are scaled to produce an indices of habitat suitability between 0 (unsuitable habitat) and 1 (optimally suitable habitat) for freshwater areas of the continental United States. Other habitat suitability models found in the literature are also included. Habitat suitability indices (HSI's) are designed for use with the habitat evaluation procedures developed by the U.S. Fish and Wildlife Service.

  10. Habitat Suitability Index Models: Green Sunfish

    USGS Publications Warehouse

    Stuber, Robert J.; Gebhart, Glen; Maughan, O. Eugene

    1982-01-01

    This is one of a series of publications that provide information on the habitat requirements of selected fish and wildlife species. Literature describing the relationship between habitat variables related to life requisites and habitat suitability for the Green sunfish (Lepomis cyanellus) are synthesized. These data are subsequently used to develop Habitat Suitability (HIS) models. The HSI models are designed to provide information that can be used in impact assessment and habitat management.

  11. Habitat Suitability Index Models: Smallmouth Buffalo

    USGS Publications Warehouse

    Edwards, Elizabeth A.; Twomey, Katie

    1982-01-01

    This is one of a series of publications that provide information on the habitat requirements of selected fish and wildlife species. Literature describing the relationship between habitat variables related to life requisites and habitat suitability for the Smallmouth buffalo (Ictiobus bubalus) are synthesized. These data are subsequently used to develop Habitat Suitability (HIS) models. The HSI models are designed to provide information that can be used in impact assessment and habitat management.

  12. Habitat Suitability Index Models: Laughing Gull

    USGS Publications Warehouse

    Zale, Alexander V.; Mulholland, Rosemarie

    1985-01-01

    A review and synthesis of existing information were used to develop a habitat model for laughing gull (Larus atricilla). The model is scaled to produce an index of habitat suitability between 0 (unsuitable habitat) and 1.0 (optimally suitable habitat) for areas along the Gulf of Mexico coast. Habitat suitability indices are designed for use with the Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service. Guidelines for application of the model and techniques for measuring model variables are described.

  13. Habitat Suitability Index Models: Rainbow Trout

    USGS Publications Warehouse

    Raleigh, Robert F.; Hickman, Terry; Solomon, R. Charles; Nelson, Patrick C.

    1984-01-01

    A review and synthesis of existing information were used to develop riverine and lacustrine habitat models for rainbow trout (Salmo gairdneri), a freshwater species. The models are scaled to produce an index of habitat suitability between 0 (unsuitable habitat) to 1 (optimally suitable habitat) for freshwater areas of the continental United States. Other habitat suitability models found in the literature are also included. Habitat suitability indexes (HSI's) are designed for use with the habitat evaluation procedures developed by the U.S. Fish and Wildlife Service. Also included are discussions of Suitability Index (SI) curves as used in the Instream Flow Incremental Methodology (IFIM) and SI curves available for an IFIM analysis of Fallfish habitat.

  14. Habitat Suitability Index Models: Lesser Scaup (Wintering)

    USGS Publications Warehouse

    Mulholland, Rosemarie

    1985-01-01

    A review and synthesis of existing information were used to develop a model for evaluating wintering habitat quality for the lesser scaup (Aythya affinis). The model is scaled to produce an index of habitat suitability between 0.0 (unsuitable habitat) to 1.0 (optimal habitat) for Southern Atlantic and Gulf of Mexico coastal areas of the continental United States. Habitat suitability indices are designed for use with the Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service Guidelines for model application and techniques for measuring model variables are provided.

  15. Habitat Suitability Index Models: Swamp Rabbit

    USGS Publications Warehouse

    Allen, Arthur W.

    1985-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the swamp rabbit (Sylvilagus aquaticus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  16. Habitat Suitability Index Models: Hairy Woodpecker

    USGS Publications Warehouse

    Sousa, Patrick J.

    1987-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the hairy woodpecker (Picoides villosus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  17. Habitat Suitability Index Models: Snowshoe Hare

    USGS Publications Warehouse

    Carreker, Raymond G.

    1985-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the Snowshoe hare (Lepus americanus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  18. Habitat Suitability Index Models: Slider Turtle

    USGS Publications Warehouse

    Morreale, Stephen J.; Gibbons, J. Whitfield

    1986-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the slider turtle (Pseudemys scripta). The model consolidates habitat use information into a framework appropriate for field application and is scaled to produce an index between 0.0 (unsuitable habitat) and 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  19. Habitat Suitability Index Models: Flathead Catfish

    USGS Publications Warehouse

    Lee, Lawrence A.; Terrell, James W.

    1987-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the flathead catfish (Pylodictis olivaris). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  20. Habitat Suitability Index Models: Cactus Wren

    USGS Publications Warehouse

    Short, Henry L.

    1985-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the cactus wren (Campylorhynchus brunneicapillus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  1. Habitat Suitability Index Models: Eastern Wild Turkey

    USGS Publications Warehouse

    Schroeder, Richard L.

    1985-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the eastern wild turkey (Meleagris gallopavo sylvestris). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  2. Habitat Suitability Index Models: Lesser Scaup (Breeding)

    USGS Publications Warehouse

    Allen, Arthur W.

    1986-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the lesser scaup (Aythya affinis). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  3. Habitat Suitability Index Models: Barred Owl

    USGS Publications Warehouse

    Allen, Arthur W.

    1987-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the barred owl (Strix varia). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  4. Habitat Suitability Index Models: Spotted Owl

    USGS Publications Warehouse

    Laymon, Stephen A.; Salwasser, Hal; Barrett, Reginald H.

    1985-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the spotted owl (Strix occidentalis). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  5. Habitat Suitability Index Models: Red King Crab

    USGS Publications Warehouse

    Jewett, Stephen C.; Onuf, Christopher P.

    1988-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for evaluating habitat of different life stages of red king crab (Paralithodes camtschatica). A model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) and 1.0 (optimum habitat) in Alaskan coastal waters, especially in the Gulf of Alaska and the southeastern Bering Sea. HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  6. Habitat Suitability Index Models: American Alligator

    USGS Publications Warehouse

    Newsom, John D.; Joanen, Ted; Howard, Rebecca J.

    1987-01-01

    A review and synthesis of existing information were used to develop a model for evaluating American alligator habitat quality. The model is applicable in marshes along the northern Gulf of Mexico. It is scaled to produce an index between 0 (unsuitable habitat) and 1.0 (optimal habitat). Habitat suitability index models are designed for use with the Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service. Guidelines for model application and techniques for measuring model variables are described.

  7. Evaluation of a habitat suitability index model

    USGS Publications Warehouse

    Farmer, A.H.; Cade, B.S.; Stauffer, D.F.

    2002-01-01

    We assisted with development of a model for maternity habitat of the Indiana bat (Myotis soda/is), for use in conducting assessments of projects potentially impacting this endangered species. We started with an existing model, modified that model in a workshop, and evaluated the revised model, using data previously collected by others. Our analyses showed that higher indices of habitat suitability were associated with sites where Indiana bats were present and, thus, the model may be useful for identifying suitable habitat. Utility of the model, however, was based on a single component-density of suitable roost trees. Percentage of landscape in forest did not allow differentiation between sites occupied and not occupied by Indiana bats. Moreover, in spite of a general opinion by participants in the workshop that bodies of water were highly productive feeding areas and that a diversity of feeding habitats was optimal, we found no evidence to support either hypothesis.

  8. Habitat Suitability Index Models: Larval and Juvenile Red Drum

    USGS Publications Warehouse

    Buckley, Jack

    1984-01-01

    A review and synthesis of existing information were used to develop a habitat model for larval and juvenile red drum. The model is scaled to produce an index of habitat suitability between 0 (unsuitable habitat) and 1 (optimally suitable habitat) for estuarine areas along the Gulf of Mexico and Atlantic coasts. Habitat suitability indices are designed for use with habitat evaluation procedures developed by the U.S. Fish and Wildlife Service. Guidelines for model application and techniques for estimating model variables are provided.

  9. Habitat Suitability Index Models and Instream Flow Suitability Curves: Pink Salmon

    USGS Publications Warehouse

    Raleigh, Robert F.; Nelson, Patrick C.

    1985-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model and instream flow suitability curves for the pink salmon (Oncorhynchus gorbuscha). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  10. Habitat Suitability Index Models and Instream Flow Suitability Curves: Chum Salmon

    USGS Publications Warehouse

    Hale, Stephen S.; McMahon, Thomas E.; Nelson, Patrick C.

    1985-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model and instream flow suitability curves for the chum salmon (Oncorhynchus keta). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  11. Habitat Suitability Index Models and Instream Flow Suitability Curves: Shortnose Sturgeon

    USGS Publications Warehouse

    Crance, Johnie H.

    1986-01-01

    A review and synthesis of existing information were used to develop habitat suitability index models and instream flow suitability curves for the shortnose sturgeon (Acipenser brevirostrum). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  12. Habitat Suitability Index Models and Instream Flow Suitability Curves: Arctic Grayling Riverine Populations

    USGS Publications Warehouse

    Hubert, Wayne A.; Helzner, Rhonda S.; Lee, Lawrence A.; Nelson, Patrick C.

    1985-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model and instream flow suitability curves for Arctic grayling (Thymallus arcticus) riverine populations. The model consolidates habitat use information into a framework appropriate for field application, and is sclaed to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  13. Habitat Suitability Index Models and Instream Flow Suitability Curves: Gizzard Shad

    USGS Publications Warehouse

    Williamson, Kathryn L.; Nelson, Patrick C.

    1985-01-01

    A review and synthesis of existing information were used to develop habitat suitability index models and instream flow suitability curves for the gizzard shad (Dorosoma cepedianum). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  14. Habitat Suitability Index Models and Instream Flow Suitability Curves: Redbreast Sunfish

    USGS Publications Warehouse

    Aho, John M.; Anderson, Charles S.; Terrell, James W.

    1986-01-01

    A review and synthesis of existing information were used to develop habitat suitability index models and instream flow suitability curves for the redbreast sunfish (Lepomis auritus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  15. The Most Suitable Habitats in the Galaxy

    NASA Astrophysics Data System (ADS)

    Mason, Paul A.; 5756406268

    2016-06-01

    Astrophysical environments constrain life on the surface of planets. The classical habitable zone characterized by stellar luminosity and temperature may be defined both for single stars and planets in binary star systems. However, in many cases, habitability is strongly affected by stellar UV radiation, winds, and catastrophic events such as nearby supernovae, GRBs, and AGN. Planets with sufficiently thick atmospheres and strong magnetic fields provide protection against radiation from the host star(s) and some nearby radiation events. Atmospheric ozone provides significant UV shield if present. Single star and binary winds provide additional protection for habitable zone planets from galactic cosmic-rays. In certain cases, binary star winds have increased protection over single stars, by providing a longer path-length against particle fluxes, since these binaries produce a higher wind flux and thus a larger “heliosphere” than a single star of comparable mass. Metallicity also plays an important role, with improvements in habitability increasing with stellar metallicity. It is proposed that circumbinary planets, Earth-like and super-Earths, with thick atmospheres, including ozone, high metallicity, and strong magnetic fields are the most suitable habitats in the Galaxy.

  16. Habitat Suitability Index Models: Diamondback Terrapin (Nesting) - Atlantic Coast

    USGS Publications Warehouse

    Palmer, William M.; Cordes, Carroll L.

    1988-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the diamondback terrapin (Malaclemys terrapin). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  17. Habitat Suitability Index Models: Bald Eagle (Breeding Season)

    USGS Publications Warehouse

    Peterson, Allen

    1986-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the bald eagle (Haliaeetus leucocephalus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  18. Habitat Suitability Index Models: Black Bear, Upper Great Lakes Region

    USGS Publications Warehouse

    Rogers, Lynn L.; Allen, Arthur W.

    1987-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the black bear (Ursus americanus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  19. Habitat Suitability Index Models: Black-Tailed Prairie Dog

    USGS Publications Warehouse

    Clippinger, Norman W.

    1989-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the black-tailed prairie dog (Cynomus ludovicianus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  20. Habitat Suitability Index Models: Moose, Lake Superior Region

    USGS Publications Warehouse

    Allen, Arthur W.; Jordan, Peter A.; Terrell, James W.

    1987-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the moose (Alces alces). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  1. Habitat Suitability Index Models: Northern Pintail (Gulf Coast Wintering)

    USGS Publications Warehouse

    Howard, Rebecca J.; Kantrud, Harold A.

    1986-01-01

    A review and synthesis of existing information were used to develop a model for evaluating wintering habitat quality for northern pintail (Anas acuta) along the Gulf of Mexico coast. The model is scaled to produce an index between unsuitable habitat) and 1.0 (optimal habitat). Habitat suitability index models are designed for use with the Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service. Guidelines for model application and techniques for measuring model variables are provided.

  2. Habitat Suitability Index Models: Wildlife Species Richness in Shelterbelts

    USGS Publications Warehouse

    Schroeder, Richard L.

    1986-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for evaluating potential species richness in shelterbelts. The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  3. Habitat Suitability Index Models: Blue-Winged Teal (Breeding)

    USGS Publications Warehouse

    Sousa, Patrick J.

    1985-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the blue-winged teal (Anas discors). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  4. Habitat Suitability Index Models: Black-Shouldered Kite

    USGS Publications Warehouse

    Faanes, Craig A.; Howard, Rebecca J.

    1987-01-01

    A review and synthesis of existing information were used to develop a model for evaluating black-shouldered kite habitat quality. The model is scaled to produce an index between 0 (unsuitable habitat) to 1.0 (optimal habitat). Habitat suitability index models are designed for use with the Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service. Guidelines for model application are provided.

  5. Habitat Suitability Index Models: Red-Spotted Newt

    USGS Publications Warehouse

    Sousa, Patrick J.

    1985-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the red-spotted newt (Notophthalmus viridescens viridescens). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  6. Habitat Suitability Index Models: Yellow-Headed Blackbird

    USGS Publications Warehouse

    Schroeder, Richard L.

    1982-01-01

    Habitat preferences of the yellow-headed blackbird (Xanthocephalus xanthocephalus) are described in this publication. It is one of a series of Habitat Suitability Index (HSI) models and was developed through an analysis of available infomration on the species-habitat requirements of the species. Habitat use information is presented in a review of the literature, followed by the development of an HSI model, designed for use in impact assessment and habitat management activities.

  7. Habitat Suitability Index Models: Red-Winged Blackbird

    USGS Publications Warehouse

    Short, Henry L.

    1985-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the red-winged blackbird (Agelaius phoeniceus L.). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  8. Habitat Suitability Index Models and Instream Flow Suitability Curves: Chinook Salmon

    USGS Publications Warehouse

    Raleigh, Robert F.; Miller, William J.; Nelson, Patrick C.

    1986-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the Chinook salmon (Oncorhynchus tshawytscha). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  9. Habitat Suitability Index Models and Instream Flow Suitability Curves: Inland Stocks of Striped Bass

    USGS Publications Warehouse

    Crance, Johnie H.

    1984-01-01

    The Habitat Suitability Index (HSI) models and instream flow Suitability Index (SI) presented in this publication aid in identifying important variables that determine the quality of striped bass habitat. Facts, ideas, and opinions obtained from published and unpublished reports, a Delphi panel of 18 striped bass experts/authorities, and the Striped Bass Committee, Southern Division, American Fisheries Society, are synthesized and presented in a format that can be used for habitat impact assessment and development of management alternatives.

  10. Habitat Suitability Index Models and Instream Flow Suitability Curves: White Bass

    USGS Publications Warehouse

    Hamilton, Karen; Nelson, Patrick C.

    1984-01-01

    Habitat characteristics important to white bass (Morone chrysops) are reviewed in this report using two techniques developed by the U.S. Fish and Wildlife Service, the Habitat Evaluation Procedures (HEP) and the Instream Flow Incremental Methodology (IFIM). The Suitability Index (SI) curves and graphs and Habitat Suitability Index (HSI) models developed in this report are based primarily on a synthesis of information obtained from a review of literature concerning the habitat requirements of the species. A discussion of IFIM and white bass SI curves available for use with IFIM is included.

  11. Regional prediction of basin-scale brown trout habitat suitability

    NASA Astrophysics Data System (ADS)

    Ceola, S.; Pugliese, A.

    2014-09-01

    In this study we propose a novel method for the estimation of ecological indices describing the habitat suitability of brown trout (Salmo trutta). Traditional hydrological tools are coupled with an innovative regional geostatistical technique, aiming at the prediction of the brown trout habitat suitability index where partial or totally ungauged conditions occur. Several methods for the assessment of ecological indices are already proposed in the scientific literature, but the possibility of exploiting a geostatistical prediction model, such as Topological Kriging, has never been investigated before. In order to develop a regional habitat suitability model we use the habitat suitability curve, obtained from measured data of brown trout adult individuals collected in several river basins across the USA. The Top-kriging prediction model is then employed to assess the spatial correlation between upstream and downstream habitat suitability indices. The study area is the Metauro River basin, located in the central part of Italy (Marche region), for which both water depth and streamflow data were collected. The present analysis focuses on discharge values corresponding to the 0.1-, 0.5-, 0.9-empirical quantiles derived from flow-duration curves available for seven gauging stations located within the study area, for which three different suitability indices (i.e. ψ10, ψ50 and ψ90) are evaluated. The results of this preliminary analysis are encouraging showing Nash-Sutcliffe efficiencies equal to 0.52, 0.65, and 0.69, respectively.

  12. Habitat suitability index models: Black-shouldered kite

    SciTech Connect

    Faanes, C.A.; Howard, R.J.

    1987-01-01

    The black-shouldered kite inhabits a disjunct range extending from California, Texas, and south intermittently to Chile and Argentina (American Ornithologists' Union 1983). Prior to the 1960's, this species occurred in low numbers across much of its range. Populations of black-shouldered kite have changed considerably within the limited area of its US range. Although considered common and widespread in California in the late 1800's, the species was largely extirpated from much of the state by the early 1900's. Since 1960, the population status and range of this raptor in North America have improved markedly. Today the black-shouldered kite in California is a common species of open and cultivated bottomland. The black-shouldered kite habitat suitability index (HSI) model is intended for use with the habitat evaluation procedures (HEP) developed by the US Fish and Wildlife Service (1980) for impact assessment and habitat management. The model was developed from a review and synthesis of existing information, and includes unpublished information that reflects the opinions of persons familiar with black-shouldered kite ecology. It is scaled to produce an index of habitat suitability between 0 (unsuitable habitat) and 1.0 (optimally suitable habitat). Assumptions used to develop the HSI model and guidelines for model application, including techniques for measuring model variables, are described. Model documentation is provided. This model is a hypothesis of species-habitat relations, not a statement of proven cause and effect. The model has not been field tested. 33 refs., 3 tabs.

  13. Habitat Suitability Index Models and Instream Flow Suitability Curves: Brown Trout

    USGS Publications Warehouse

    Raleigh, Robert F.; Zuckerman, Laurence D.; Nelson, Patrick C.

    1984-01-01

    The Habitat Suitability Index (HSI) models presented in this publication aid in identifying important habitat variables for brown trout (Salmo trutto Linneas). Facts, ideas, and concepts obtained from the research literature and expert reviews are synthesized and presented in a format that can be used for impact assessment. A brief discussion of the appropriateness of using selected Suitability Index (SI) curves from HSI models as a component of the Instream Flow Incremental Methodology (IFIM) is provided. Additional SI curves, developed specifically for analysis of brown trout habitat with IFIM, also are presented.

  14. Habitat Suitability Index Models and Instream Flow Suitability Curves: Spotted Bass

    USGS Publications Warehouse

    McMahon, Thomas E.; Gebhart, Glen; Maughan, O. Eugene; Nelson, Patrick C.

    1984-01-01

    The Habitat Suitability Index (HSI) models presented in this publication aid in identifying habitat variable important to the growth and survival of spotted bass (Micropterus punctulatus). Facts, ideas, and concepts obtained from the research literature and expert reviews are synthesized and presented in a format that can be used for impact assessment. The models are hypotheses of species-habitat relationships, and model users should recognize that the degree of veracity of the HSI model, SI graphs, and assumptions will vary according to geographical area and the extent of the data base for individual variables. A brief discussion of selected Suitability Index (SI) curves as used in the Instream Flow Incremental Methodology (IFIM), and a discussion of SI curves available for the IFIM analysis of Spotted bass habitat are also included.

  15. A Tamarisk Habitat Suitability Map for the Continental US

    NASA Technical Reports Server (NTRS)

    Morisette, Jeffrey T.; Jernevich, Catherine S.; Ullah, Asad; Cai, Weijie; Pedelty, Jeffrey A.; Gentle, Jim; Stohlgren, Thomas J.; Schnase, John L.

    2005-01-01

    This paper presents a national-scale map of habitat suitability for a high-priority invasive species, Tamarisk (Tamarisk spp., salt cedar). We successfully integrate satellite data and tens of thousands of field sampling points through logistic regression modeling to create a habitat suitability map that is 90% accurate. This interagency effort uses field data collected and coordinated through the US Geological Survey and nation-wide environmental data layers derived from NASA s MODerate Resolution Imaging Spectroradiometer (MODIS). We demonstrate the utilization of the map by ranking the lower 48 US states (and the District of Columbia) based upon their absolute, as well as proportional, areas of highly likely and moderately likely habitat for Tamarisk. The interagency effort and modeling approach presented here could be applied to map other harmful species in the US and globally.

  16. The Importance of Biologically Relevant Microclimates in Habitat Suitability Assessments

    PubMed Central

    Varner, Johanna; Dearing, M. Denise

    2014-01-01

    Predicting habitat suitability under climate change is vital to conserving biodiversity. However, current species distribution models rely on coarse scale climate data, whereas fine scale microclimate data may be necessary to assess habitat suitability and generate predictive models. Here, we evaluate disparities between temperature data at the coarse scale from weather stations versus fine-scale data measured in microhabitats required for a climate-sensitive mammal, the American pika (Ochotona princeps). We collected two years of temperature data in occupied talus habitats predicted to be suitable (high elevation) and unsuitable (low elevation) by the bioclimatic envelope approach. At low elevations, talus surface and interstitial microclimates drastically differed from ambient temperatures measured on-site and at a nearby weather station. Interstitial talus temperatures were frequently decoupled from high ambient temperatures, resulting in instantaneous disparities of over 30°C between these two measurements. Microhabitat temperatures were also highly heterogeneous, such that temperature measurements within the same patch of talus were not more correlated than measurements at distant patches. An experimental manipulation revealed that vegetation cover may cool the talus surface by up to 10°C during the summer, which may contribute to this spatial heterogeneity. Finally, low elevation microclimates were milder and less variable than typical alpine habitat, suggesting that, counter to species distribution model predictions, these seemingly unsuitable habitats may actually be better refugia for this species under climate change. These results highlight the importance of fine-scale microhabitat data in habitat assessments and underscore the notion that some critical refugia may be counterintuitive. PMID:25115894

  17. Habitat suitability index models: greater white-fronted goose (wintering). [Anser albifrons

    SciTech Connect

    Kaminski, R.M.

    1986-07-01

    A review and synthesis of available information were used to develop models for indexing the potential suitability of agricultural and natural wetland habitats for wintering white-fronted geese (Anser albifrons). The model is scaled to produce indices of habitat suitability from 0 (unsuitable habitat) to 1.0 (optimal habitat) primarily for wintering habitat in southwest Louisiana and southwest Texas. Habitat suitability indices are designed for use with Habitat Evaluations Procedures previously developed by the US Fish and Wildlife Service.

  18. Spatially-explicit hydrologic controls on benthic invertebrate habitat suitability

    NASA Astrophysics Data System (ADS)

    Ceola, Serena; Bertuzzo, Enrico; Singer, Gabriel; Battin, Tom; Montanari, Alberto; Rinaldo, Andrea

    2014-05-01

    Streamflow variability is a major determinant of basin-scale distribution of benthic invertebrates. Here we present a probabilistic approach for a spatially explicit quantitative assessment of benthic invertebrate abundance as derived from near-bed flow variability throughout an entire stream network. We consider aquatic invertebrates as these are widely employed as sensitive indicators of fluvial ecosystem health and human-induced perturbations. Moving from the analytical characterization of site-specific probability distribution functions of streamflow and bottom shear stress, we achieve a spatial extension to a stream network ranging up to 5th order. Bottom shear stress distributions, coupled with habitat suitability curves derived from field studies, are then used to produce maps of invertebrate habitat suitability based on shear stress conditions. The proposed framework allows to inspect the possible impacts of human-induced perturbations of streamflow variability on river ecology. We apply our approach to an Austrian river network, for which rainfall and streamflow time series, river network hydraulic properties and local information on invertebrate abundance for a limited number of sites are available. This allows a comparison between observed species density versus modeled habitat suitability based on shear stress. Although the proposed strategy neglects ecological determinants other than hydraulic ones and thus represents an ecological minimal model, it allows derivation of important implications of water resource management and fluvial ecosystem protection for basin-scale distribution patterns of organisms.

  19. Habitat Suitability Index Models: Northern Gulf of Mexico Brown Shrimp and White Shrimp

    USGS Publications Warehouse

    Turner, Robert Eugene; Brody, Michael S.

    1983-01-01

    A review and synthesis of existing information were used to develop estuarine habitat models for brown shrimp (Penaeus aztecus) and white shrimp (Penaeus setiferus). The models are scaled to produce an index of habitat suitability between 0 (unsuitable habitat) to 1 (optimally suitable habitat) for estuarine areas of the northern Gulf of Mexico. Habitat suitability indexes are designed for use with the habitat evaluation procedures developed by the U.S. Fish and Wildlife Service.

  20. Modeling mountain pine beetle habitat suitability within Sequoia National Park

    NASA Astrophysics Data System (ADS)

    Nguyen, Andrew

    Understanding significant changes in climate and their effects on timber resources can help forest managers make better decisions regarding the preservation of natural resources and land management. These changes may to alter natural ecosystems dependent on historical and current climate conditions. Increasing mountain pine beetle (MBP) outbreaks within the southern Sierra Nevada are the result of these alterations. This study better understands MPB behavior within Sequoia National Park (SNP) and model its current and future habitat distribution. Variables contributing to MPB spread are vegetation stress, soil moisture, temperature, precipitation, disturbance, and presence of Ponderosa (Pinus ponderosa) and Lodgepole (Pinus contorta) pine trees. These variables were obtained using various modeled, insitu, and remotely sensed sources. The generalized additive model (GAM) was used to calculate the statistical significance of each variable contributing to MPB spread and also created maps identifying habitat suitability. Results indicate vegetation stress and forest disturbance to be variables most indicative of MPB spread. Additionally, the model was able to detect habitat suitability of MPB with a 45% accuracy concluding that a geospatial driven modeling approach can be used to delineate potential MPB spread within SNP.

  1. Using habitat suitability models to target invasive plant species surveys

    USGS Publications Warehouse

    Crall, Alycia W.; Jarnevich, Catherine S.; Panke, Brendon; Young, Nick; Renz, Mark; Morisette, Jeffrey

    2013-01-01

    Managers need new tools for detecting the movement and spread of nonnative, invasive species. Habitat suitability models are a popular tool for mapping the potential distribution of current invaders, but the ability of these models to prioritize monitoring efforts has not been tested in the field. We tested the utility of an iterative sampling design (i.e., models based on field observations used to guide subsequent field data collection to improve the model), hypothesizing that model performance would increase when new data were gathered from targeted sampling using criteria based on the initial model results. We also tested the ability of habitat suitability models to predict the spread of invasive species, hypothesizing that models would accurately predict occurrences in the field, and that the use of targeted sampling would detect more species with less sampling effort than a nontargeted approach. We tested these hypotheses on two species at the state scale (Centaurea stoebe and Pastinaca sativa) in Wisconsin (USA), and one genus at the regional scale (Tamarix) in the western United States. These initial data were merged with environmental data at 30-m2 resolution for Wisconsin and 1-km2 resolution for the western United States to produce our first iteration models. We stratified these initial models to target field sampling and compared our models and success at detecting our species of interest to other surveys being conducted during the same field season (i.e., nontargeted sampling). Although more data did not always improve our models based on correct classification rate (CCR), sensitivity, specificity, kappa, or area under the curve (AUC), our models generated from targeted sampling data always performed better than models generated from nontargeted data. For Wisconsin species, the model described actual locations in the field fairly well (kappa = 0.51, 0.19, P 2) = 47.42, P < 0.01). From these findings, we conclude that habitat suitability models can be

  2. Faecal corticosterone metabolite concentrations are not a good predictor of habitat suitability for common gartersnakes

    PubMed Central

    Halliday, William D.; Gilmour, Kathleen M.; Blouin-Demers, Gabriel

    2015-01-01

    Measuring habitat suitability is important in conservation and in wildlife management. Measuring the abundance or presence–absence of a species in various habitats is not sufficient to measure habitat suitability because these metrics can be poor predictors of population success. Therefore, having some measure of population success is essential in assessing habitat suitability, but estimating population success is difficult. Identifying suitable proxies for population success could thus be beneficial. We examined whether faecal corticosterone metabolite (fCM) concentrations could be used as a proxy for habitat suitability in common gartersnakes (Thamnophis sirtalis). We conducted a validation study and confirmed that fCM concentrations indeed reflect circulating corticosterone concentrations. We estimated abundance, reproductive output and growth rate of gartersnakes in field and in forest habitat and we also measured fCM concentrations of gartersnakes from these same habitats. Common gartersnakes were more abundant and had higher reproductive outputs and higher growth rates in field habitat than in forest habitat, but fCM concentrations did not differ between the same two habitats. Our results suggest either that fCM concentrations are not a useful metric of habitat suitability in common gartersnakes or that the difference in suitability between the two habitats was too small to induce changes in fCM concentrations. Incorporating fitness metrics in estimates of habitat suitability is important, but these metrics of fitness have to be sensitive enough to vary between habitats. PMID:27293731

  3. Habitat Suitability Index Models: Southern Red-Backed Vole (Western United States)

    USGS Publications Warehouse

    Allen, Arthur W.

    1983-01-01

    Habitat preferences of the southern red-backed vole (Clethrionomys gapperi) are described in this publication, which is one of a series of Habitat Suitability Index (HSI) models. A review and synthesis of the literature is followed by development of a model of the species-habitat requirements of the southern red-backed vole. Habitat suitability indexes are designed for use with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  4. Habitat Suitability Index Models: Black-Bellied Whistling-Duck (Breeding)

    USGS Publications Warehouse

    McKenzie, Paul M.; Zwank, Phillip J.

    1988-01-01

    A review and synthesis of existing information were used to develop a model for evaluating the quality of habitat for breeding black-bellied whistling-ducks. The model is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimal habitat). Habitat suitability index models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service. Guidelines for model application and techniques for measuring model variable are provided.

  5. Habitat Suitability Index Models: Greater Prairie-Chicken (Multiple Levels of Resolution)

    USGS Publications Warehouse

    Prose, Bart L.

    1985-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the greater prairie-chicken (Tympanuchus cupido pinnatus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  6. STREAM FISH HABITAT SUITABILITY AND THE RISK OF POPULATION DECLINE

    EPA Science Inventory

    Over half of the streams in the Mid-Atlantic Highlands have fish communities that are in fair or poor condition, and the EPA concluded that physical habitat alteration represents the greatest potential stressor across this region. A quantitative method for relating habitat quali...

  7. A HABITAT SUITABILITY INDEX FOR THE BAY SCALLOP ARGOPECTEN IRRADIANS

    EPA Science Inventory

    Platform Presentation at a Scientific Meeting. A survey of Lagoon Pond, Martha's Vineyard, MA, USA was conducted in September 2005 to determine the combination of habitat factors most highly correlated with bay scallop (Argopecten irradians) abundance. A stratified random samplin...

  8. Variation in habitat suitability does not always relate to variation in species' plant functional traits

    PubMed Central

    Thuiller, Wilfried; Albert, Cécile H.; Dubuis, Anne; Randin, Christophe; Guisan, Antoine

    2010-01-01

    Habitat suitability models, which relate species occurrences to environmental variables, are assumed to predict suitable conditions for a given species. If these models are reliable, they should relate to change in plant growth and function. In this paper, we ask the question whether habitat suitability models are able to predict variation in plant functional traits, often assumed to be a good surrogate for a species' overall health and vigour. Using a thorough sampling design, we show a tight link between variation in plant functional traits and habitat suitability for some species, but not for others. Our contrasting results pave the way towards a better understanding of how species cope with varying habitat conditions and demonstrate that habitat suitability models can provide meaningful descriptions of the functional niche in some cases, but not in others. PMID:19793738

  9. Temporally dynamic habitat suitability predicts genetic relatedness among caribou

    PubMed Central

    Yannic, Glenn; Pellissier, Loïc; Le Corre, Maël; Dussault, Christian; Bernatchez, Louis; Côté, Steeve D.

    2014-01-01

    Landscape heterogeneity plays a central role in shaping ecological and evolutionary processes. While species utilization of the landscape is usually viewed as constant within a year, the spatial distribution of individuals is likely to vary in time in relation to particular seasonal needs. Understanding temporal variation in landscape use and genetic connectivity has direct conservation implications. Here, we modelled the daily use of the landscape by caribou in Quebec and Labrador, Canada and tested its ability to explain the genetic relatedness among individuals. We assessed habitat selection using locations of collared individuals in migratory herds and static occurrences from sedentary groups. Connectivity models based on habitat use outperformed a baseline isolation-by-distance model in explaining genetic relatedness, suggesting that variations in landscape features such as snow, vegetation productivity and land use modulate connectivity among populations. Connectivity surfaces derived from habitat use were the best predictors of genetic relatedness. The relationship between connectivity surface and genetic relatedness varied in time and peaked during the rutting period. Landscape permeability in the period of mate searching is especially important to allow gene flow among populations. Our study highlights the importance of considering temporal variations in habitat selection for optimizing connectivity across heterogeneous landscape and counter habitat fragmentation. PMID:25122223

  10. Temporally dynamic habitat suitability predicts genetic relatedness among caribou.

    PubMed

    Yannic, Glenn; Pellissier, Loïc; Le Corre, Maël; Dussault, Christian; Bernatchez, Louis; Côté, Steeve D

    2014-10-01

    Landscape heterogeneity plays a central role in shaping ecological and evolutionary processes. While species utilization of the landscape is usually viewed as constant within a year, the spatial distribution of individuals is likely to vary in time in relation to particular seasonal needs. Understanding temporal variation in landscape use and genetic connectivity has direct conservation implications. Here, we modelled the daily use of the landscape by caribou in Quebec and Labrador, Canada and tested its ability to explain the genetic relatedness among individuals. We assessed habitat selection using locations of collared individuals in migratory herds and static occurrences from sedentary groups. Connectivity models based on habitat use outperformed a baseline isolation-by-distance model in explaining genetic relatedness, suggesting that variations in landscape features such as snow, vegetation productivity and land use modulate connectivity among populations. Connectivity surfaces derived from habitat use were the best predictors of genetic relatedness. The relationship between connectivity surface and genetic relatedness varied in time and peaked during the rutting period. Landscape permeability in the period of mate searching is especially important to allow gene flow among populations. Our study highlights the importance of considering temporal variations in habitat selection for optimizing connectivity across heterogeneous landscape and counter habitat fragmentation. PMID:25122223

  11. A HABITAT SUITABILITY INDEX FOR THE BAY SCALLOP ARGOPECTEN IRRADIANS

    EPA Science Inventory

    Poster presentation at a scientific meeting. A survey of Lagoon Pond, Martha's Vineyard, MA, USA was conducted in September 2005 to determine the combination of habitat factors most highly correlated with the bay scallop Argopecten irradians) abundance. A stratified random samp...

  12. Modeling the habitat suitability for the arbovirus vector Aedes albopictus (Diptera: Culicidae) in Germany.

    PubMed

    Koch, Lisa K; Cunze, Sarah; Werblow, Antje; Kochmann, Judith; Dörge, Dorian D; Mehlhorn, Heinz; Klimpel, Sven

    2016-03-01

    Climatic changes raise the risk of re-emergence of arthropod-borne virus outbreaks globally. These viruses are transmitted by arthropod vectors, often mosquitoes. Due to increasing worldwide trade and tourism, these vector species are often accidentally introduced into many countries beyond their former distribution range. Aedes albopictus, a well-known disease vector, was detected for the first time in Germany in 2007, but seems to have failed establishment until today. However, the species is known to occur in other temperate regions and a risk for establishment in Germany remains, especially in the face of predicted climate change. Thus, the goal of the study was to estimate the potential distribution of Ae. albopictus in Germany. We used ecological niche modeling in order to estimate the potential habitat suitability for this species under current and projected future climatic conditions. According to our model, there are already two areas in western and southern Germany that appear suitable for Ae. albopictus under current climatic conditions. One of these areas lies in Baden-Wuerttemberg, the other in North-Rhine Westphalia in the Ruhr region. Furthermore, projections under future climatic conditions show an increase of the modeled habitat suitability throughout Germany. Ae. albopictus is supposed to be better acclimated to colder temperatures than other tropical vectors and thus, might become, triggered by climate change, a serious threat to public health in Germany. Our modeling results can help optimizing the design of monitoring programs currently in place in Germany. PMID:26634351

  13. The areal extent of brown shrimp habitat suitability in Mobile Bay, Alabama, USA: targeting vegetated habitat restoration.

    PubMed

    Smith, Lisa M; Nestlerode, Janet A; Harwell, Linda C; Bourgeois, Pete

    2010-12-01

    The availability of wetlands and shallow water habitats significantly influences Gulf of Mexico (GOM) penaeid shrimp fishery productivity. However, the GOM region has the highest rate of wetland loss in the USA. Protection and management of these vital GOM habitats are critical to sustainable shrimp fisheries. Brown shrimp (Farfantepenaeus aztecus) are a major component of GOM fisheries. We present an approach for estimating the areal extent of suitable habitat for post-larval and juvenile brown shrimp in Mobile Bay, Alabama, using an existing habitat suitability index model for the northern GOM calculated from probabilistic survey of water quality and sediment data, land cover data, and submerged aquatic vegetation coverages. This estuarine scale approach is intended to support targeted protection and restoration of these habitats. These analyses indicate that approximately 60% of the area of Mobile Bay is categorized as suitable to near optimal for post-larval and juvenile shrimp and 38% of the area is marginally to minimally suitable. We identify potential units within Mobile Bay for targeted restoration to improve habitat suitability. PMID:20082136

  14. The areal extent of brown shrimp habitat suitability in Mobile Bay, Alabama, USA: Targeting vegetated habitat restoration

    USGS Publications Warehouse

    Smith, L.M.; Nestlerode, J.A.; Harwell, L.C.; Bourgeois, P.

    2010-01-01

    The availability of wetlands and shallow water habitats significantly influences Gulf of Mexico (GOM) penaeid shrimp fishery productivity. However, the GOM region has the highest rate of wetland loss in the USA. Protection and management of these vital GOM habitats are critical to sustainable shrimp fisheries. Brown shrimp (Farfantepenaeus aztecus) are a major component of GOM fisheries. We present an approach for estimating the areal extent of suitable habitat for post-larval and juvenile brown shrimp in Mobile Bay, Alabama, using an existing habitat suitability index model for the northern GOM calculated from probabilistic survey of water quality and sediment data, land cover data, and submerged aquatic vegetation coverages. This estuarine scale approach is intended to support targeted protection and restoration of these habitats. These analyses indicate that approximately 60% of the area of Mobile Bay is categorized as suitable to near optimal for post-larval and juvenile shrimp and 38% of the area is marginally to minimally suitable. We identify potential units within Mobile Bay for targeted restoration to improve habitat suitability. ?? 2010 Springer Science+Business Media B.V.

  15. Development of a Habitat Suitability Index Model for the Sage Sparrow on the Hanford Site

    SciTech Connect

    Duberstein, Corey A.; Simmons, Mary Ann; Sackschewsky, Michael R.; Becker, James M.

    2008-01-01

    Mitigation threshold guidelines for the Hanford Site are based on habitat requirements of the sage sparrow (Amphispiza belli) and only apply to areas with a mature sagebrush (Artemisia tridentata) overstory and a native understory. The sage sparrow habitat requirements are based on literature values and are not specific to the Hanford Site. To refine these guidelines for the Site, a multi-year study was undertaken to quantify habitat characteristics of sage sparrow territories. These characteristics were then used to develop a habitat suitability index (HSI) model which can be used to estimate the habitat value of specific locations on the Site.

  16. Modeling habitat suitability for Greater Rheas based on satellite image texture.

    PubMed

    Bellis, Laura M; Pidgeon, Anna M; Radeloff, Volker C; St-Louis, Véronique; Navarro, Joaquín L; Martella, Mónica B

    2008-12-01

    Many wild species are affected by human activities occurring at broad spatial scales. For instance, in South America, habitat loss threatens Greater Rhea (Rhea americana) populations, making it important to model and map their habitat to better target conservation efforts. Spatially explicit habitat modeling is a powerful approach to understand and predict species occurrence and abundance. One problem with this approach is that commonly used land cover classifications do not capture the variability within a given land cover class that might constitute important habitat attribute information. Texture measures derived from remote sensing images quantify the variability in habitat features among and within habitat types; hence they are potentially a powerful tool to assess species-habitat relationships. Our goal was to explore the utility of texture measures for habitat modeling and to develop a habitat suitability map for Greater Rheas at the home range level in grasslands of Argentina. Greater Rhea group size obtained from aerial surveys was regressed against distance to roads, houses, and water, and land cover class abundance (dicotyledons, crops, grassland, forest, and bare soil), normalized difference vegetation index (NDVI), and selected first- and second-order texture measures derived from Landsat Thematic Mapper (TM) imagery. Among univariate models, Rhea group size was most strongly positively correlated with texture variables derived from near infrared reflectance measurement (TM band 4). The best multiple regression models explained 78% of the variability in Greater Rhea group size. Our results suggest that texture variables captured habitat heterogeneity that the conventional land cover classification did not detect. We used Greater Rhea group size as an indicator of habitat suitability; we categorized model output into different habitat quality classes. Only 16% of the study area represented high-quality habitat for Greater Rheas (group size > or =15

  17. A Bayesian spawning habitat suitability model for American shad in southeastern United States rivers

    USGS Publications Warehouse

    Hightower, Joseph E.; Harris, Julianne E.; Raabe, Joshua K.; Brownell, Prescott; Drew, C. Ashton

    2012-01-01

    Habitat suitability index models for American shad Alosa sapidissima were developed by Stier and Crance in 1985. These models, which were based on a combination of published information and expert opinion, are often used to make decisions about hydropower dam operations and fish passage. The purpose of this study was to develop updated habitat suitability index models for spawning American shad in the southeastern United States, building on the many field and laboratory studies completed since 1985. We surveyed biologists who had knowledge about American shad spawning grounds, assembled a panel of experts to discuss important habitat variables, and used raw data from published and unpublished studies to develop new habitat suitability curves. The updated curves are based on resource selection functions, which can model habitat selectivity based on use and availability of particular habitats. Using field data collected in eight rivers from Virginia to Florida (Mattaponi, Pamunkey, Roanoke, Tar, Neuse, Cape Fear, Pee Dee, St. Johns), we obtained new curves for temperature, current velocity, and depth that were generally similar to the original models. Our new suitability function for substrate was also similar to the original pattern, except that sand (optimal in the original model) has a very low estimated suitability. The Bayesian approach that we used to develop habitat suitability curves provides an objective framework for updating the model as new studies are completed and for testing the model's applicability in other parts of the species' range.

  18. Habitat Suitability Index Models: Alewife and Blueback Herring

    USGS Publications Warehouse

    Pardue, Garland B.

    1983-01-01

    Alewives and blueback herring are anadromous clupeids found along the Atlantic coast in marine, estuarine, and riverine habitats, depending upon life stage. Both are important commercial species, used fresh or salted for human consumption, and used as crab bait, fish meal (particularly in animal food manufacturing), and fish oil. Alewife and blueback herring are marketed collectively as 'river herring,' a term that will be used for both species in this report. River herring play important ecological roles. In marine, estuarine, and riverine food webs, they occupy a level between zooplankton, their principal food, and piscivores.

  19. Predicted Deep-Sea Coral Habitat Suitability for the U.S. West Coast

    PubMed Central

    Guinotte, John M.; Davies, Andrew J.

    2014-01-01

    Regional scale habitat suitability models provide finer scale resolution and more focused predictions of where organisms may occur. Previous modelling approaches have focused primarily on local and/or global scales, while regional scale models have been relatively few. In this study, regional scale predictive habitat models are presented for deep-sea corals for the U.S. West Coast (California, Oregon and Washington). Model results are intended to aid in future research or mapping efforts and to assess potential coral habitat suitability both within and outside existing bottom trawl closures (i.e. Essential Fish Habitat (EFH)) and identify suitable habitat within U.S. National Marine Sanctuaries (NMS). Deep-sea coral habitat suitability was modelled at 500 m×500 m spatial resolution using a range of physical, chemical and environmental variables known or thought to influence the distribution of deep-sea corals. Using a spatial partitioning cross-validation approach, maximum entropy models identified slope, temperature, salinity and depth as important predictors for most deep-sea coral taxa. Large areas of highly suitable deep-sea coral habitat were predicted both within and outside of existing bottom trawl closures and NMS boundaries. Predicted habitat suitability over regional scales are not currently able to identify coral areas with pin point accuracy and probably overpredict actual coral distribution due to model limitations and unincorporated variables (i.e. data on distribution of hard substrate) that are known to limit their distribution. Predicted habitat results should be used in conjunction with multibeam bathymetry, geological mapping and other tools to guide future research efforts to areas with the highest probability of harboring deep-sea corals. Field validation of predicted habitat is needed to quantify model accuracy, particularly in areas that have not been sampled. PMID:24759613

  20. A habitat suitability model for Chinese sturgeon determined using the generalized additive method

    NASA Astrophysics Data System (ADS)

    Yi, Yujun; Sun, Jie; Zhang, Shanghong

    2016-03-01

    The Chinese sturgeon is a type of large anadromous fish that migrates between the ocean and rivers. Because of the construction of dams, this sturgeon's migration path has been cut off, and this species currently is on the verge of extinction. Simulating suitable environmental conditions for spawning followed by repairing or rebuilding its spawning grounds are effective ways to protect this species. Various habitat suitability models based on expert knowledge have been used to evaluate the suitability of spawning habitat. In this study, a two-dimensional hydraulic simulation is used to inform a habitat suitability model based on the generalized additive method (GAM). The GAM is based on real data. The values of water depth and velocity are calculated first via the hydrodynamic model and later applied in the GAM. The final habitat suitability model is validated using the catch per unit effort (CPUEd) data of 1999 and 2003. The model results show that a velocity of 1.06-1.56 m/s and a depth of 13.33-20.33 m are highly suitable ranges for the Chinese sturgeon to spawn. The hydraulic habitat suitability indexes (HHSI) for seven discharges (4000; 9000; 12,000; 16,000; 20,000; 30,000; and 40,000 m3/s) are calculated to evaluate integrated habitat suitability. The results show that the integrated habitat suitability reaches its highest value at a discharge of 16,000 m3/s. This study is the first to apply a GAM to evaluate the suitability of spawning grounds for the Chinese sturgeon. The study provides a reference for the identification of potential spawning grounds in the entire basin.

  1. Bald eagle habitat suitability on Melton Hill Reservoir and the Clinch River

    SciTech Connect

    Buehler, D.A.

    1994-09-01

    The area around Melton Hill Reservoir and sections of the Clinch River along the Oak Ridge Reservation (ORR) provide suitable habitat for bald eagles for both breeding and wintering activities. Primary limitations on habitat suitability appear to be human activity in aquatic habitats and along shoreline areas, and human development along shoreline areas. ORR provides the majority of the suitable habitat because shoreline development is very limited. Four eagle management strategies discussed for ORR include planning development away from high-quality habitats, allowing forest stands near water to mature, conducting timber stand improvement to foster growth and development in pines and hardwoods, and using introductions to foster the development of a breeding population. The primary objective of this project was to make a qualitative assessment of bald eagle habitat suitability along Melton Hill Reservoir and the Clinch River and in adjacent areas on the ORR, including the proposed Advanced Neutron Source site. This survey`s aim was to provide ORR managers with an indication of whether suitable habitat exists and, if so, where it occurs on ORR. This information should provide the basis for incorporating eagle management into the overall ORR land management plan.

  2. SMALL MAMMALS: CONSEQUENCES OF STOCHASTIC DATA VARIATION FOR MODELING INDICATORS OF HABITAT SUITABILITY FOR A WELL-STUDIED RESOURCE

    EPA Science Inventory

    Increasingly, models of physical habitat variables (i.e. vegetation, soil) are utilized as indicators of small mammal habitat suitability or quality. Presumably, use of physical habitat models indicating habitat suitability or quality would be improved and enhanced by the extens...

  3. Combining Data to Assess of the Habitat Suitability of Patches of Streambed

    NASA Astrophysics Data System (ADS)

    Wicks, C. M.; Aley, T.; Ashley, D.; Noltie, D.

    2011-12-01

    Many of the aquatic animals that live in cave streams are threatened, endangered, or endemic. Management plans needed to conserve the aquatic ecosystems within which these animals live must be based on an understanding of the food webs, life histories, and habitat suitability. However, for many of these ecosystems, there is very little information about the food webs, life histories, or habitat suitability. If information is available, that information is frequently incomplete. One aspect of habitat suitability is the stability of the streambed sediment. Sediment that can be scoured over a wide range of hydrologic conditions is not suitable habitat as scour events disrupt the streambed sediment resulting in dispersal or possibly death of the animals; whereas, sediment that cannot be scoured would be suitable habitat. Assessing sediment stability requires hydrologic and sedimentologic data and assessing habitat suitability requires population consensus data. Rarely are the three disparate sets of data collected. Our objective was to develop a method that can be used to assess streambed stability using disparate data sets. At locations along the cave streams for which we have conducted population consensuses and particle-size distribution data, we used the flow competence method to assess streambed stability. At each location, the depth of water that would result in scour of the sediment was calculated (a constant) and was compared to the measured or calculated depth of the water (a function of time). In absence of measured depth of water data, we used a numerical model of unsteady state flow along the two main stream channels to calculate the depth of water at each consensus location in each ecosystem. Habitat suitability was evaluated by comparing the presence or absence of animals at each consensus location with our understanding of the stability of the streambed at the same location. With a calibrated numerical model and water depth and sedimentologic data, this

  4. From points to forecasts: Predicting invasive species habitat suitability in the near term

    USGS Publications Warehouse

    Holcombe, Tracy R.; Stohlgren, Thomas J.; Jarnevich, Catherine S.

    2010-01-01

    We used near-term climate scenarios for the continental United States, to model 12 invasive plants species. We created three potential habitat suitability models for each species using maximum entropy modeling: (1) current; (2) 2020; and (3) 2035. Area under the curve values for the models ranged from 0.92 to 0.70, with 10 of the 12 being above 0.83 suggesting strong and predictable species-environment matching. Change in area between the current potential habitat and 2035 ranged from a potential habitat loss of about 217,000 km2, to a potential habitat gain of about 133,000 km2.

  5. Assessing range-wide habitat suitability for the Lesser Prairie-Chicken

    USGS Publications Warehouse

    Jarnevich, Catherine S.; Holcombe, Tracy R.; Grisham, Blake A.; Timmer, Jennifer M.; Boal, Clint W.; Butler, Matthew; Pitman, James C.; Kyle, Sean; Klute, David; Beauprez, Grant M.; Janus, Allan; Van Pelt, William E.

    2016-01-01

    Population declines of many wildlife species have been linked to habitat loss incurred through land-use change. Incorporation of conservation planning into development planning may mitigate these impacts. The threatened Lesser Prairie-Chicken (Tympanuchus pallidicinctus) is experiencing loss of native habitat and high levels of energy development across its multijurisdictional range. Our goal was to explore relationships of the species occurrence with landscape characteristics and anthropogenic effects influencing its distribution through evaluation of habitat suitability associated with one particular habitat usage, lekking. Lekking has been relatively well-surveyed, though not consistently, in all jurisdictions. All five states in which Lesser Prairie-Chickens occur cooperated in development of a Maxent habitat suitability model. We created two models, one with state as a factor and one without state. When state was included it was the most important predictor, followed by percent of land cover consisting of known or suspected used vegetation classes within a 5000 m area around a lek. Without state, land cover was the most important predictor of relative habitat suitability for leks. Among the anthropogenic predictors, landscape condition, a measure of human impact integrated across several factors, was most important, ranking third in importance without state. These results quantify the relative suitability of the landscape within the current occupied range of Lesser Prairie-Chickens. These models, combined with other landscape information, form the basis of a habitat assessment tool that can be used to guide siting of development projects and targeting of areas for conservation.

  6. Landscape-level Connectivity in Coastal Southern California, USA, as Assessed through Carnivore Habitat Suitability

    USGS Publications Warehouse

    Hunter, R.D.; Fisher, R.N.; Crooks, K.R.

    2003-01-01

    Although the fragmentation of the natural landscape of coastal southern California, USA, is accelerating, large-scale assessments of regional connectivity are lacking. Because of their large area requirements and long dispersal movements, mammalian carnivores can be effective focal species to use when evaluating landscape-level connectivity. Our goal was to make an initial assessment of the extent of landscape-level connectivity in coastal southern California using mountain lions (Felis concolor [Linnaeusl) and bobcats (Felis rufus [Shreber]) as focal species. We first characterized habitat preferences for mountain lions and bobcats from previously derived habitat relationship models for these species; the resulting maps provided a coarse view of habitat preferences for use at regional scales. We then constructed GIS models to evaluate the disturbance impact of roadways and development, major determinants of carnivore distribution and abundance in the south coast region. Finally, we combined the habitat relationship models with the disturbance impact models to characterize habitat connectivity for mountain lions and bobcats in the ecoregion. Habitat connectivity in the ecoregion appeared higher for bobcats than for mountain lions due in part to higher habitat suitability for bobcats in coastal lowland areas. Our models suggest that much of the key carnivore habitat in the coastal southern California is at risk; over 80% of high suitability habitat and over 90% of medium suitability habitat for carnivores is found in the least protected land management classes. Overall, these models allow for (1) identification of core habitat blocks for carnivores and key landscape connections between core areas, (2) evaluation of the level of protection of these areas, and (3) a regional framework within which to develop and coordinate local management and conservation plans.

  7. Analyzing the habitat suitability for migratory birds at the Chongming Dongtan Nature Reserve in Shanghai, China

    NASA Astrophysics Data System (ADS)

    Tian, Bo; Zhou, Yunxuan; Zhang, Liquan; Yuan, Lin

    2008-11-01

    The Dongtan Nature Reserve, one of the largest nature reserves in East Asia, is located in the mouth of the Yangtze Estuary and is an important habitat for migratory birds. The Dongtan wetlands were listed in the Chinese Protected Wetlands in 1992, and were designated as internationally important under the Ramsar Wetlands Convention in 2001 and as a national nature reserve in 2005. By their very nature and location, the estuarine and coastal habitats are dynamic and their biodiversity conservation and management relies on up-to-date spatial information. By establishing qualitative and quantitative relationships between bird populations and key habitat factors such as elevation, land cover type, tidal creek density and macrophytobenthos biomass, we developed an object-oriented image approach, in conjunction with Geographical Information Systems and the data from current field surveys, to analyze and assess the habitat suitability for the main types of birds, namely Anatidae, Charadriidae, Ardeidae and Laridae, at the reserve. The results from this study showed that about 40% of the total area of the Dongtan Reserve contained suitable habitats for these four bird families. The Scirpus mariqueter zone, mudflat zone, and tidal creeks were the most important habitats for these birds. This study indicated the potential of this approach for objective and effective evaluation of the species habitat suitability in a dynamic estuarine and coastal area. The implications of the results as a tool for biodiversity conservation, wetland conservation, and ecosystem management are discussed.

  8. Habitat suitability and conservation of the Giant Gartersnake (Thamnophis gigas) in the Sacramento Valley of California

    USGS Publications Warehouse

    Halstead, B.J.; Wylie, G.D.; Casazza, M.L.

    2010-01-01

    Resource managers often have little information regarding the habitat requirements and distribution of rare species. Factor analysis-based habitat suitability models describe the ecological niche of a species and identify locations where these conditions occur on the landscape using existing occurrence data. We used factor analyses to assess the suitability of habitats for Thamnophis gigas (Giant Gartersnake), a rare, threatened species endemic to the Central Valley of California, USA, and to map the locations of habitat suitable for T. gigas in the Sacramento Valley. Factor analyses indicated that the niche of T. gigas is composed of sites near rice agriculture with low stream densities. Sites with high canal densities and near wetlands also appeared suitable, but results for these variables were sensitive to potential sampling bias. In the Sacramento Valley, suitable habitats occur primarily in the central portion of the valley floor. Based upon the results of the factor analyses, recovery planning for T. gigas will require an on-the-ground assessment of the current distribution and abundance of T. gigas, maintaining the few remaining natural wetlands and the practice of rice agriculture in the Sacramento Valley, and studying the effects of agricultural practices and land use changes on populations of T. gigas. ?? 2010 by the American Society of Ichthyologists and Herpetologists.

  9. Habitat suitability and conservation of the giant gartersnake (Thamnophis gigas) in the Sacramento Valley of California

    USGS Publications Warehouse

    Halstead, Brian J.; Wylie, Glenn D.; Casazza, Michael L.

    2010-01-01

    Resource managers often have little information regarding the habitat requirements and distribution of rare species. Factor analysis-based habitat suitability models describe the ecological niche of a species and identify locations where these conditions occur on the landscape using existing occurrence data.We used factor analyses to assess the suitability of habitats for Thamnophis gigas (Giant Gartersnake), a rare, threatened species endemic to the Central Valley of California, USA, and to map the locations of habitat suitable for T. gigas in the Sacramento Valley. Factor analyses indicated that the niche of T. gigas is composed of sites near rice agriculture with low stream densities. Sites with high canal densities and near wetlands also appeared suitable, but results for these variables were sensitive to potential sampling bias. In the Sacramento Valley, suitable habitats occur primarily in the central portion of the valley floor. Based upon the results of the factor analyses, recovery planning for T. gigas will require an on-the-ground assessment of the current distribution and abundance of T. gigas, maintaining the few remaining natural wetlands and the practice of rice agriculture in the Sacramento Valley, and studying the effects of agricultural practices and land use changes on populations of T. gigas.

  10. Modelling the habitat suitability of cetaceans: Example of the sperm whale in the northwestern Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Praca, Emilie; Gannier, Alexandre; Das, Krishna; Laran, Sophie

    2009-04-01

    Cetaceans are mobile and spend long periods underwater. Because of this, modelling their habitat could be subject to a serious problem of false absence. Furthermore, extensive surveys at sea are time and money consuming, and presence-absence data are difficult to apply. This study compares the ability of two presence-absence and two presence-only habitat modelling methods and uses the example of the sperm whale ( Physeter macrocephalus) in the northwestern Mediterranean Sea. The data consist of summer visual and acoustical detections of sperm whales, compiled between 1998 and 2005. Habitat maps were computed using topographical and hydrological eco-geographical variables. Four methods were compared: principal component analysis (PCA), ecological niche factor analysis (ENFA), generalized linear model (GLM) and multivariate adaptive regression splines (MARS). The evaluation of the models was achieved by calculating the receiver operating characteristic (ROC) of the models and their respective area under the curve (AUC). Presence-absence methods (GLM, AUC=0.70, and MARS, AUC=0.79) presented better AUC than presence-only methods (PCA, AUC=0.58, and ENFA, AUC=0.66), but this difference was not statistically significant, except between the MARS and the PCA models. The four models showed an influence of both topographical and hydrological factors, but the resulting habitat suitability maps differed. The core habitat on the continental slope was well highlighted by the four models, while GLM and MARS maps also showed a suitable habitat in the offshore waters. Presence-absence methods are therefore recommended for modelling the habitat suitability of cetaceans, as they seem more accurate to highlight complex habitat. However, the use of presence-only techniques, in particular ENFA, could be very useful for a first model of the habitat range or when important surveys at sea are not possible.

  11. Spatial and temporal shifts in suitable habitat of juvenile southern flounder (Paralichthys lethostigma)

    NASA Astrophysics Data System (ADS)

    Furey, Nathan B.; Rooker, Jay R.

    2013-02-01

    Factors influencing suitable habitats of juvenile southern flounder (Paralichthys lethostigma) within the Galveston Bay Complex (GBC), Texas, were assessed using generalized additive models (GAM). Fishery independent data collected with bag seines throughout the GBC from 1999 to 2009 were used to predict the probability of southern flounder occurrence. Binomial GAMs were used to assess presence/absence of southern flounder and models included temporal variables, benthic variables such as distance to habitats generated within a geographic information system, and physicochemical conditions of the water column. Separate models were generated for newly settled southern flounder, young-of-the-year (YOY) southern flounder observed in the summer, and YOY southern flounder observed in fall based on size and collection month. Factors affecting southern flounder occurrence changed seasonally, as did the corresponding shifts in the spatial distribution of suitable habitat. Temporal effects (year and month) were retained in all models. Physicochemical conditions (temperature, turbidity, and measures of environmental variability), and the presence of seagrass beds were influential for newly settled southern flounder. Distance to marine and/or freshwater sources were found to be important for YOY southern flounder in the summer and fall seasons. The abundance of brown shrimp was found to only influence the distribution of YOY southern flounder in the fall, when intermediate abundances of the potential prey item increased the occurrence of southern flounder. After model completion, the availability and spatial distribution of suitable habitat within the GBC was predicted using available environmental and spatial data for 2005. Spatial distributions of predicted suitable habitat stress the relative importance of West Bay during the newly settled stage and in the fall season, and Upper Bay during the summer and fall of the first year of life. These models demonstrate the potential

  12. Hydrologic and water-quality rehabilitation of environments for suitable fish habitat

    NASA Astrophysics Data System (ADS)

    Zhao, C. S.; Yang, S. T.; Xiang, H.; Liu, C. M.; Zhang, H. T.; Yang, Z. L.; Zhang, Y.; Sun, Y.; Mitrovic, S. M.; Yu, Q.; Lim, R. P.

    2015-11-01

    Aquatic ecological rehabilitation is attracting increasing public and research attention, but without knowledge of the responses of aquatic species to their habitats the success of habitat restoration is uncertain. Thus efficient study of species response to habitat, through which to prioritize the habitat factors influencing aquatic ecosystems, is highly important. However many current models have too high requirement for assemblage information and have great bias in results due to consideration of only the species' attribute of presence/absence, abundance or biomass, thus hindering the wider utility of these models. This paper, using fish as a case, presents a framework for identification of high-priority habitat factors based on the responses of aquatic species to their habitats, using presence/absence, abundance and biomass data. This framework consists of four newly developed sub-models aiming to determine weightings for the evaluation of species' contributions to their communities, to quantitatively calculate an integrated habitat suitability index for multi-species based on habitat factors, to assess the suitable probability of habitat factors and to assess the rehabilitation priority of habitat factors. The framework closely links hydrologic, physical and chemical habitat factors to fish assemblage attributes drawn from monitoring datasets on hydrology, water quality and fish assemblages at a total of 144 sites, where 5084 fish were sampled and tested. Breakpoint identification techniques based on curvature in cumulated dominance along with a newly developed weighting calculation model based on theory of mass systems were used to help identify the dominant fish, based on which the presence and abundance of multiple fish were normalized to estimate the integrated habitat suitability index along gradients of various factors, based on their variation with principal habitat factors. Then, the appropriate probability of every principal habitat factor was

  13. Comparing Habitat Suitability and Connectivity Modeling Methods for Conserving Pronghorn Migrations

    PubMed Central

    Poor, Erin E.; Loucks, Colby; Jakes, Andrew; Urban, Dean L.

    2012-01-01

    Terrestrial long-distance migrations are declining globally: in North America, nearly 75% have been lost. Yet there has been limited research comparing habitat suitability and connectivity models to identify migration corridors across increasingly fragmented landscapes. Here we use pronghorn (Antilocapra americana) migrations in prairie habitat to compare two types of models that identify habitat suitability: maximum entropy (Maxent) and expert-based (Analytic Hierarchy Process). We used distance to wells, distance to water, NDVI, land cover, distance to roads, terrain shape and fence presence to parameterize the models. We then used the output of these models as cost surfaces to compare two common connectivity models, least-cost modeling (LCM) and circuit theory. Using pronghorn movement data from spring and fall migrations, we identified potential migration corridors by combining each habitat suitability model with each connectivity model. The best performing model combination was Maxent with LCM corridors across both seasons. Maxent out-performed expert-based habitat suitability models for both spring and fall migrations. However, expert-based corridors can perform relatively well and are a cost-effective alternative if species location data are unavailable. Corridors created using LCM out-performed circuit theory, as measured by the number of pronghorn GPS locations present within the corridors. We suggest the use of a tiered approach using different corridor widths for prioritizing conservation and mitigation actions, such as fence removal or conservation easements. PMID:23166656

  14. Comparing habitat suitability and connectivity modeling methods for conserving pronghorn migrations.

    PubMed

    Poor, Erin E; Loucks, Colby; Jakes, Andrew; Urban, Dean L

    2012-01-01

    Terrestrial long-distance migrations are declining globally: in North America, nearly 75% have been lost. Yet there has been limited research comparing habitat suitability and connectivity models to identify migration corridors across increasingly fragmented landscapes. Here we use pronghorn (Antilocapra americana) migrations in prairie habitat to compare two types of models that identify habitat suitability: maximum entropy (Maxent) and expert-based (Analytic Hierarchy Process). We used distance to wells, distance to water, NDVI, land cover, distance to roads, terrain shape and fence presence to parameterize the models. We then used the output of these models as cost surfaces to compare two common connectivity models, least-cost modeling (LCM) and circuit theory. Using pronghorn movement data from spring and fall migrations, we identified potential migration corridors by combining each habitat suitability model with each connectivity model. The best performing model combination was Maxent with LCM corridors across both seasons. Maxent out-performed expert-based habitat suitability models for both spring and fall migrations. However, expert-based corridors can perform relatively well and are a cost-effective alternative if species location data are unavailable. Corridors created using LCM out-performed circuit theory, as measured by the number of pronghorn GPS locations present within the corridors. We suggest the use of a tiered approach using different corridor widths for prioritizing conservation and mitigation actions, such as fence removal or conservation easements. PMID:23166656

  15. Habitat suitability analysis of eelgrass Zostera marina L. in the subtidal zone of Xiaoheishan Island

    NASA Astrophysics Data System (ADS)

    Zhou, Jian; Wang, Qixiang; Zhao, Wenxi; Yu, Daode; Guan, Shuguang

    2016-01-01

    We present a GIS-based habitat suitability index (HSI) model to identify suitable areas for Zostera marina L. restoration in the subtidal zone of Xiaoheishan Island. The controlling factors in the model, in order of importance, are Secchi depth, sediment composition, water temperature, salinity, current velocity, water depth and nutrient quality. Specific factor piecewise functions have been used to transform parameter values into normalized quality indexes. The weight of each factor was defined using expert knowledge and the analytic hierarchy process (AHP) method. All of the data thus obtained were interpolated using the inverse distance weighted (IDW) interpolation method to create maps for the entire region. In this study, the analysis of habitat suitability in the subtidal zone of Xiaoheishan Island was conducted for four seasons. According to the GIS-based HSI model, the optimal habitat of Zostera marina L. appears in spring, although habitat remains suitable all year round. On the whole, the optimum site for eelgrass restoration is located in the eastern region, followed by the western and southern regions. We believe that the GIS-based HSI model could be a promising tool to select sites for Zostera marina L. restoration and could also be applicable in other types of habitat evaluation.

  16. Global habitat suitability for framework-forming cold-water corals.

    PubMed

    Davies, Andrew J; Guinotte, John M

    2011-01-01

    Predictive habitat models are increasingly being used by conservationists, researchers and governmental bodies to identify vulnerable ecosystems and species' distributions in areas that have not been sampled. However, in the deep sea, several limitations have restricted the widespread utilisation of this approach. These range from issues with the accuracy of species presences, the lack of reliable absence data and the limited spatial resolution of environmental factors known or thought to control deep-sea species' distributions. To address these problems, global habitat suitability models have been generated for five species of framework-forming scleractinian corals by taking the best available data and using a novel approach to generate high resolution maps of seafloor conditions. High-resolution global bathymetry was used to resample gridded data from sources such as World Ocean Atlas to produce continuous 30-arc second (∼1 km(2)) global grids for environmental, chemical and physical data of the world's oceans. The increased area and resolution of the environmental variables resulted in a greater number of coral presence records being incorporated into habitat models and higher accuracy of model predictions. The most important factors in determining cold-water coral habitat suitability were depth, temperature, aragonite saturation state and salinity. Model outputs indicated the majority of suitable coral habitat is likely to occur on the continental shelves and slopes of the Atlantic, South Pacific and Indian Oceans. The North Pacific has very little suitable scleractinian coral habitat. Numerous small scale features (i.e., seamounts), which have not been sampled or identified as having a high probability of supporting cold-water coral habitat were identified in all ocean basins. Field validation of newly identified areas is needed to determine the accuracy of model results, assess the utility of modelling efforts to identify vulnerable marine ecosystems for

  17. Global Habitat Suitability for Framework-Forming Cold-Water Corals

    PubMed Central

    Davies, Andrew J.; Guinotte, John M.

    2011-01-01

    Predictive habitat models are increasingly being used by conservationists, researchers and governmental bodies to identify vulnerable ecosystems and species' distributions in areas that have not been sampled. However, in the deep sea, several limitations have restricted the widespread utilisation of this approach. These range from issues with the accuracy of species presences, the lack of reliable absence data and the limited spatial resolution of environmental factors known or thought to control deep-sea species' distributions. To address these problems, global habitat suitability models have been generated for five species of framework-forming scleractinian corals by taking the best available data and using a novel approach to generate high resolution maps of seafloor conditions. High-resolution global bathymetry was used to resample gridded data from sources such as World Ocean Atlas to produce continuous 30-arc second (∼1 km2) global grids for environmental, chemical and physical data of the world's oceans. The increased area and resolution of the environmental variables resulted in a greater number of coral presence records being incorporated into habitat models and higher accuracy of model predictions. The most important factors in determining cold-water coral habitat suitability were depth, temperature, aragonite saturation state and salinity. Model outputs indicated the majority of suitable coral habitat is likely to occur on the continental shelves and slopes of the Atlantic, South Pacific and Indian Oceans. The North Pacific has very little suitable scleractinian coral habitat. Numerous small scale features (i.e., seamounts), which have not been sampled or identified as having a high probability of supporting cold-water coral habitat were identified in all ocean basins. Field validation of newly identified areas is needed to determine the accuracy of model results, assess the utility of modelling efforts to identify vulnerable marine ecosystems for

  18. Climate change may threaten habitat suitability of threatened plant species within Chinese nature reserves

    PubMed Central

    Wan, Jizhong

    2016-01-01

    Climate change has the potential to alter the distributions of threatened plant species, and may therefore diminish the capacity of nature reserves to protect threatened plant species. Chinese nature reserves contain a rich diversity of plant species that are at risk of becoming more threatened by climate change. Hence, it is urgent to identify the extent to which future climate change may compromise the suitability of threatened plant species habitats within Chinese nature reserves. Here, we modelled the climate suitability of 82 threatened plant species within 168 nature reserves across climate change scenarios. We used Maxent modelling based on species occurrence localities and evaluated climate change impacts using the magnitude of change in climate suitability and the degree of overlap between current and future climatically suitable habitats. There was a significant relationship between overlap with current and future climate suitability of all threatened plant species habitats and the magnitude of changes in climate suitability. Our projections estimate that the climate suitability of more than 60 threatened plant species will decrease and that climate change threatens the habitat suitability of plant species in more than 130 nature reserves under the low, medium, and high greenhouse gas concentration scenarios by both 2050s and 2080s. Furthermore, future climate change may substantially threaten tree plant species through changes in annual mean temperature. These results indicate that climate change may threaten plant species that occur within Chinese nature reserves. Therefore, we suggest that climate change projections should be integrated into the conservation and management of threatened plant species within nature reserves. PMID:27326373

  19. Ensemble modeling to predict habitat suitability for a large-scale disturbance specialist

    PubMed Central

    Latif, Quresh S; Saab, Victoria A; Dudley, Jonathan G; Hollenbeck, Jeff P

    2013-01-01

    To conserve habitat for disturbance specialist species, ecologists must identify where individuals will likely settle in newly disturbed areas. Habitat suitability models can predict which sites at new disturbances will most likely attract specialists. Without validation data from newly disturbed areas, however, the best approach for maximizing predictive accuracy can be unclear (Northwestern U.S.A.). We predicted habitat suitability for nesting Black-backed Woodpeckers (Picoides arcticus; a burned-forest specialist) at 20 recently (≤6 years postwildfire) burned locations in Montana using models calibrated with data from three locations in Washington, Oregon, and Idaho. We developed 8 models using three techniques (weighted logistic regression, Maxent, and Mahalanobis D2 models) and various combinations of four environmental variables describing burn severity, the north–south orientation of topographic slope, and prefire canopy cover. After translating model predictions into binary classifications (0 = low suitability to unsuitable, 1 = high to moderate suitability), we compiled “ensemble predictions,” consisting of the number of models (0–8) predicting any given site as highly suitable. The suitability status for 40% of the area burned by eastside Montana wildfires was consistent across models and therefore robust to uncertainty in the relative accuracy of particular models and in alternative ecological hypotheses they described. Ensemble predictions exhibited two desirable properties: (1) a positive relationship with apparent rates of nest occurrence at calibration locations and (2) declining model agreement outside surveyed environments consistent with our reduced confidence in novel (i.e., “no-analogue”) environments. Areas of disagreement among models suggested where future surveys could help validate and refine models for an improved understanding of Black-backed Woodpecker nesting habitat relationships. Ensemble predictions presented here can

  20. Predictive habitat suitability models to aid conservation of elasmobranch diversity in the central Mediterranean Sea.

    PubMed

    Lauria, V; Gristina, M; Attrill, M J; Fiorentino, F; Garofalo, G

    2015-01-01

    Commercial fisheries have dramatically impacted elasmobranch populations worldwide. With high capture and bycatch rates, the abundance of many species is rapidly declining and around a quarter of the world's sharks and rays are threatened with extinction. At a regional scale this negative trend has also been evidenced in the central Mediterranean Sea, where bottom-trawl fisheries have affected the biomass of certain rays (e.g. Raja clavata) and sharks (e.g. Mustelus spp.). Detailed knowledge of elasmobranch habitat requirements is essential for biodiversity conservation and fisheries management, but this is often hampered by a poor understanding of their spatial ecology. Habitat suitability models were used to investigate the habitat preference of nine elasmobranch species and their overall diversity (number of species) in relation to five environmental predictors (i.e. depth, sea surface temperature, surface salinity, slope and rugosity) in the central Mediterranean Sea. Results showed that depth, seafloor morphology and sea surface temperature were the main drivers for elasmobranch habitat suitability. Predictive distribution maps revealed different species-specific patterns of suitable habitat while high assemblage diversity was predicted in deeper offshore waters (400-800 m depth). This study helps to identify priority conservation areas and diversity hot-spots for rare and endangered elasmobranchs in the Mediterranean Sea. PMID:26272502

  1. Predictive habitat suitability models to aid conservation of elasmobranch diversity in the central Mediterranean Sea

    PubMed Central

    Lauria, V.; Gristina, M.; Attrill, M. J.; Fiorentino, F.; Garofalo, G.

    2015-01-01

    Commercial fisheries have dramatically impacted elasmobranch populations worldwide. With high capture and bycatch rates, the abundance of many species is rapidly declining and around a quarter of the world’s sharks and rays are threatened with extinction. At a regional scale this negative trend has also been evidenced in the central Mediterranean Sea, where bottom-trawl fisheries have affected the biomass of certain rays (e.g. Raja clavata) and sharks (e.g. Mustelus spp.). Detailed knowledge of elasmobranch habitat requirements is essential for biodiversity conservation and fisheries management, but this is often hampered by a poor understanding of their spatial ecology. Habitat suitability models were used to investigate the habitat preference of nine elasmobranch species and their overall diversity (number of species) in relation to five environmental predictors (i.e. depth, sea surface temperature, surface salinity, slope and rugosity) in the central Mediterranean Sea. Results showed that depth, seafloor morphology and sea surface temperature were the main drivers for elasmobranch habitat suitability. Predictive distribution maps revealed different species-specific patterns of suitable habitat while high assemblage diversity was predicted in deeper offshore waters (400–800 m depth). This study helps to identify priority conservation areas and diversity hot-spots for rare and endangered elasmobranchs in the Mediterranean Sea. PMID:26272502

  2. Predictive habitat suitability models to aid conservation of elasmobranch diversity in the central Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Lauria, V.; Gristina, M.; Attrill, M. J.; Fiorentino, F.; Garofalo, G.

    2015-08-01

    Commercial fisheries have dramatically impacted elasmobranch populations worldwide. With high capture and bycatch rates, the abundance of many species is rapidly declining and around a quarter of the world’s sharks and rays are threatened with extinction. At a regional scale this negative trend has also been evidenced in the central Mediterranean Sea, where bottom-trawl fisheries have affected the biomass of certain rays (e.g. Raja clavata) and sharks (e.g. Mustelus spp.). Detailed knowledge of elasmobranch habitat requirements is essential for biodiversity conservation and fisheries management, but this is often hampered by a poor understanding of their spatial ecology. Habitat suitability models were used to investigate the habitat preference of nine elasmobranch species and their overall diversity (number of species) in relation to five environmental predictors (i.e. depth, sea surface temperature, surface salinity, slope and rugosity) in the central Mediterranean Sea. Results showed that depth, seafloor morphology and sea surface temperature were the main drivers for elasmobranch habitat suitability. Predictive distribution maps revealed different species-specific patterns of suitable habitat while high assemblage diversity was predicted in deeper offshore waters (400-800 m depth). This study helps to identify priority conservation areas and diversity hot-spots for rare and endangered elasmobranchs in the Mediterranean Sea.

  3. Estimating the distribution of harvested estuarine bivalves with natural-history-based habitat suitability models

    EPA Science Inventory

    Habitat suitability models are useful to forecast how environmental change may affect the abundance or distribution of species of concern. In the case of harvested bivalves, those models may be used to estimate the vulnerability of this valued ecosystem good to natural or human-...

  4. ASSESSING HABITAT SUITABILITY AT MULTIPLE SCALES: A LANDSCAPE-LEVEL APPROACH

    EPA Science Inventory

    The distribution and abundance of many plants and animals are influenced by thespatial arrangement of suitable habitats across landscapes. We derived habitatmaps from a digital land cover map of the apprx 178,000 km-2Chesapeake Bay Watershed by using a spatial filtering algori...

  5. Modeling spatial and temporal variation of suitable nursery habitats for Atlantic sturgeon in the Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Niklitschek, Edwin J.; Secor, David H.

    2005-07-01

    For rare and endangered species, bioenergetics modeling can represent a valuable approach for understanding issues of habitat value and connectivity among potential habitats within nurseries in restoration programs. We used multivariable bioenergetics and survival models for Atlantic sturgeon to generate spatially explicit maps of potential production in the Chesapeake Bay. For the period 1993-2002, spatial and temporal patterns in water quality effects (temperature, dissolved oxygen [DO] and salinity) on potential production were evaluated. In addition, two forecasted scenarios were modeled: one implementing newly revised U.S. Environmental Protection Agency (EPA) DO-criteria for the Chesapeake Bay, and the other assuming a bay-wide increase of 1 °C due to an underlying trend in regional climate. Atlantic sturgeon's low (survival/growth) tolerance to temperatures >28 °C was a critical constraint during their first 1-2 summers of life. Hatched in freshwater (spring to mid-summer), young-of-the-year were predicted to occupy cooler (deeper) areas as temperature approached sub-lethal levels. While most thermal refuges were located down-estuary, a large fraction of potential refuges were unsuitable due to persistent hypoxia and/or salinity levels beyond the limited osmoregulatory capabilities of early juvenile Atlantic sturgeon. As a result, suitable summer habitats for juvenile Atlantic sturgeons in the Chesapeake Bay were predicted to be spatially restricted and variable between years, ranging from 0 to 35% of the modeled bay surface area. In critical (drought) years, almost no summer habitat was predicted to be available for juvenile Atlantic sturgeon. Value and size of nursery habitat was highly sensitive to climatic oscillations and anthropogenic interventions affecting freshwater inflow, water temperature and/or DO. Achieving EPA DO-criteria for the Chesapeake Bay was predicted to increase total suitable habitat by 13% for an average year, while increasing

  6. Predicting the effects of proposed Mississippi River diversions on oyster habitat quality; application of an oyster habitat suitability index model

    USGS Publications Warehouse

    Soniat, Thomas M.; Conzelmann, Craig P.; Byrd, Jason D.; Roszell, Dustin P.; Bridevaux, Joshua L.; Suir, Kevin J.; Colley, Susan B.

    2013-01-01

    In an attempt to decelerate the rate of coastal erosion and wetland loss, and protect human communities, the state of Louisiana developed its Comprehensive Master Plan for a Sustainable Coast. The master plan proposes a combination of restoration efforts including shoreline protection, marsh creation, sediment diversions, and ridge, barrier island, and hydrological restoration. Coastal restoration projects, particularly the large-scale diversions of fresh water from the Mississippi River, needed to supply sediment to an eroding coast potentially impact oyster populations and oyster habitat. An oyster habitat suitability index model is presented that evaluates the effects of a proposed sediment and freshwater diversion into Lower Breton Sound. Voluminous freshwater, needed to suspend and broadly distribute river sediment, will push optimal salinities for oysters seaward and beyond many of the existing reefs. Implementation and operation of the Lower Breton Sound diversion structure as proposed would render about 6,173 ha of hard bottom immediately east of the Mississippi River unsuitable for the sustained cultivation of oysters. If historical harvests are to be maintained in this region, a massive and unprecedented effort to relocate private leases and restore oyster bottoms would be required. Habitat suitability index model results indicate that the appropriate location for such efforts are to the east and north of the Mississippi River Gulf Outlet.

  7. Simultaneous modeling of habitat suitability, occupancy, and relative abundance: African elephants in Zimbabwe

    USGS Publications Warehouse

    Martin, Julien; Chamaille-Jammes, Simon; Nichols, James D.; Fritz, Herve; Hines, James E.; Fonnesbeck, Christopher J.; MacKenzie, Darryl I.; Bailey, Larissa L.

    2010-01-01

    The recent development of statistical models such as dynamic site occupancy models provides the opportunity to address fairly complex management and conservation problems with relatively simple models. However, surprisingly few empirical studies have simultaneously modeled habitat suitability and occupancy status of organisms over large landscapes for management purposes. Joint modeling of these components is particularly important in the context of management of wild populations, as it provides a more coherent framework to investigate the population dynamics of organisms in space and time for the application of management decision tools. We applied such an approach to the study of water hole use by African elephants in Hwange National Park, Zimbabwe. Here we show how such methodology may be implemented and derive estimates of annual transition probabilities among three dry-season states for water holes: (1) unsuitable state (dry water holes with no elephants); (2) suitable state (water hole with water) with low abundance of elephants; and (3) suitable state with high abundance of elephants. We found that annual rainfall and the number of neighboring water holes influenced the transition probabilities among these three states. Because of an increase in elephant densities in the park during the study period, we also found that transition probabilities from low abundance to high abundance states increased over time. The application of the joint habitat–occupancy models provides a coherent framework to examine how habitat suitability and factors that affect habitat suitability influence the distribution and abundance of organisms. We discuss how these simple models can further be used to apply structured decision-making tools in order to derive decisions that are optimal relative to specified management objectives. The modeling framework presented in this paper should be applicable to a wide range of existing data sets and should help to address important ecological

  8. Seasonal habitat suitability modeling and factors affecting the distribution of Asian Houbara in East Iran.

    PubMed

    Haghania, Ali; Aliabadian, Mansour; Sarhangzadeh, Jalil; Setoodehc, Ahad

    2016-08-01

    In this study, maximum entropy models were developed in four seasons to evaluate habitat suitability and factors affecting Asian Houbara in Iran. Environmental variables used in modeling consisted of 42 environmental and climate variables for Nayband wildlife refuge and 36 environmental and climate variables for Petregan protected area. Also, seasonal overlap area were obtained using the ENM TOOLS software. The results showed that the most important factors affecting habitat suitability of the Asian Houbara in all seasons included the ratio of distance to hill, the type of Artemisia-Gymnocarpus, distance to the slope (8-12%) in the Nayband wildlife refuge, distance to the type of Artemisia aucheri, distance to the Land Passion, and distance to the dry land farming in the Petregan region. In summer, the most suitable habitat is Nayband but is Petergan during fall-winter. there is maximum overlap in summer, and the least overlap in the spring these areas. The results of this study can be used as a valuable tool in implementing conservation and management strategies, in order to increase desirable habitats in the eastern part of Iran. PMID:27570839

  9. Scale considerations in monitoring greater sage-grouse ( Centrocercus urophasianus) vegetation structure and habitat suitability within nesting habitat in western Wyoming

    NASA Astrophysics Data System (ADS)

    Zabihi Afratakhti, Khodabakhsh

    Disturbance of nesting habitat associated with energy development has contributed to population declines of greater sage-grouse (Centrocercus urophasianus) in western Wyoming. Greater sage-grouse, rely on sagebrush ecosystems during all of their life stages. Specific criteria for suitable nesting habitat for the species includes both amount and distribution of sagebrush and herbaceous cover. Loss of suitable sagebrush habitat makes the identification of remaining suitable habitat critical for long-term management of the species. This research documents spatial patterns of vegetation structure within greater sage-grouse nesting habitat to compare shrub configuration (shrub patchiness) between nest and random non-nest locations at very fine scales. Additionally, we examine the applicability of gap intercept techniques to quantify shrub structural characteristics (shrub height and patchiness). Finally, the suitability of nesting habitats was mapped using biophysical features and anthropogenic disturbances at fine to broad scales. Spatial vegetation patterns vary with scale, and spatial homogeneity of sagebrush stands declines with increasing shrub height. Canopy gap intercept techniques reliably quantify composition, configuration, and height of shrub cover. The proportion of shrub cover and non-shrub gaps can be used as a compositional attribute that characterizes nesting habitat at the broad scale (across kilometers). In addition, variation in gap sizes within shrub cover, or shrub patchiness is a habitat characteristic that differentiates nesting and non-nest habitat at fine scales. Shrub cover-to-gap proportion, shrub spatial configuration, and mean shrub heights are important vegetative traits that characterize sage-grouse nesting habitat. At broad scales, habitat suitability for nesting is related to both anthropogenic disturbances and the suitability of biophysical features (e.g., slope, aspect, vegetation type and composition). Information about habitat

  10. Linking landscapes and habitat suitability scores for diadromous fish restoration in the susquehanna river basin

    USGS Publications Warehouse

    Kocovsky, P.M.; Ross, R.M.; Dropkin, D.S.; Campbell, J.M.

    2008-01-01

    Dams within the Susquehanna River drainage, Pennsylvania, are potential barriers to migration of diadromous fishes, and many are under consideration for removal to facilitate fish passage. To provide useful input for prioritizing dam removal, we examined relations between landscape-scale factors and habitat suitability indices (HSIs) for native diadromous species of the Susquehanna River. We used two different methods (U.S. Fish and Wildlife Service method: Stier and Crance [1985], Ross et al. [1993a, 1993b, 1997], and Pardue [1983]; Pennsylvania State University method: Carline et al. [1994]) to calculate HSIs for several life stages of American shad Alosa sapidissima, alewives Alosa pseudoharengus, and blueback herring Alosa aestivalis and a single HSI for American eels Anguilla rostrata based on habitat variables measured at transects spaced every 5 km on six major Susquehanna River tributaries. Using geographical information systems, we calculated land use and geologic variables upstream from each transect and associated those data with HSIs calculated at each transect. We then performed canonical correlation analysis to determine how HSIs were linked to geologic and land use factors. Canonical correlation analysis identified the proportion of watershed underlain by carbonate rock as a positive correlate of HSIs for all species and life stages except American eels and juvenile blueback herring. We hypothesize that potential mechanisms linking carbonate rock to habitat suitability include increased productivity and buffering capacity. No other consistent patterns of positive or negative correlation between landscape-scale factors and HSIs were evident. This analysis will be useful for prioritizing removal of dams in the Susquehanna River drainage, because it provides a broad perspective on relationships between habitat suitability for diadromous fishes and easily measured landscape factors. This approach can be applied elsewhere to elucidate relationships

  11. Future habitat suitability for coral reef ecosystems under global warming and ocean acidification

    PubMed Central

    Couce, Elena; Ridgwell, Andy; Hendy, Erica J

    2013-01-01

    Rising atmospheric CO2 concentrations are placing spatially divergent stresses on the world's tropical coral reefs through increasing ocean surface temperatures and ocean acidification. We show how these two stressors combine to alter the global habitat suitability for shallow coral reef ecosystems, using statistical Bioclimatic Envelope Models rather than basing projections on any a priori assumptions of physiological tolerances or fixed thresholds. We apply two different modeling approaches (Maximum Entropy and Boosted Regression Trees) with two levels of complexity (one a simplified and reduced environmental variable version of the other). Our models project a marked temperature-driven decline in habitat suitability for many of the most significant and bio-diverse tropical coral regions, particularly in the central Indo-Pacific. This is accompanied by a temperature-driven poleward range expansion of favorable conditions accelerating up to 40–70 km per decade by 2070. We find that ocean acidification is less influential for determining future habitat suitability than warming, and its deleterious effects are centered evenly in both hemispheres between 5° and 20° latitude. Contrary to expectations, the combined impact of ocean surface temperature rise and acidification leads to little, if any, degradation in future habitat suitability across much of the Atlantic and areas currently considered ‘marginal’ for tropical corals, such as the eastern Equatorial Pacific. These results are consistent with fossil evidence of range expansions during past warm periods. In addition, the simplified models are particularly sensitive to short-term temperature variations and their projections correlate well with reported locations of bleaching events. Our approach offers new insights into the relative impact of two global environmental pressures associated with rising atmospheric CO2 on potential future habitats, but greater understanding of past and current controls on

  12. Dynamic habitat suitability modelling reveals rapid poleward distribution shift in a mobile apex predator.

    PubMed

    Hill, Nicholas J; Tobin, Andrew J; Reside, April E; Pepperell, Julian G; Bridge, Tom C L

    2016-03-01

    Many taxa are undergoing distribution shifts in response to anthropogenic climate change. However, detecting a climate signal in mobile species is difficult due to their wide-ranging, patchy distributions, often driven by natural climate variability. For example, difficulties associated with assessing pelagic fish distributions have rendered fisheries management ill-equipped to adapt to the challenges posed by climate change, leaving pelagic species and ecosystems vulnerable. Here, we demonstrate the value of citizen science data for modelling the dynamic habitat suitability of a mobile pelagic predator (black marlin, Istiompax indica) within the south-west Pacific Ocean. The extensive spatial and temporal coverage of our occurrence data set (n = 18 717), collected at high resolution (~1.85 km(2) ), enabled identification of suitable habitat at monthly time steps over a 16-year period (1998-2013). We identified considerable monthly, seasonal and interannual variability in the extent and distribution of suitable habitat, predominately driven by chlorophyll a and sea surface height. Interannual variability correlated with El Nino Southern Oscillation (ENSO) events, with suitable habitat extending up to ~300 km further south during La Nina events. Despite the strong influence of ENSO, our model revealed a rapid poleward shift in the geometric mean of black marlin habitat, occurring at 88.2 km decade(-1) . By incorporating multiple environmental factors at monthly time steps, we were able to demonstrate a rapid distribution shift in a mobile pelagic species. Our findings suggest that the rapid velocity of climate change in the south-west Pacific Ocean is likely affecting mobile pelagic species, indicating that they may be more vulnerable to climate change than previously thought. PMID:26464050

  13. Test of a habitat suitability index for black bears in the southern Appalachians

    USGS Publications Warehouse

    Mitchell, M.S.; Zimmerman, J.W.; Powell, R.A.

    2002-01-01

    We present a habitat suitability index (HSI) model for black bears (Ursus americanus) living in the southern Appalachians that was developed a priori from the literature, then tested using location and home range data collected in the Pisgah Bear Sanctuary, North Carolina, over a 12-year period. The HSI was developed and initially tested using habitat and bear data collected over 2 years in the sanctuary. We increased number of habitat sampling sites, included data collected in areas affected by timber harvest, used more recent Geographic Information System (GIS) technology to create a more accurate depiction of the HSI for the sanctuary, evaluated effects of input variability on HSI values, and duplicated the original tests using more data. We found that the HSI predicted habitat selection by bears on population and individual levels and the distribution of collared bears were positively correlated with HSI values. We found a stronger relationship between habitat selection by bears and a second-generation HSI. We evaluated our model with criteria suggested by Roloff and Kernohan (1999) for evaluating HSI model reliability and concluded that our model was reliable and robust. The model's strength is that it was developed as an a priori hypothesis directly modeling the relationship between critical resources and fitness of bears and tested with independent data. We present the HSI spatially as a continuous fitness surface where potential contribution of habitat to the fitness of a bear is depicted at each point in space.

  14. Using forest inventory data to assess fisher resting habitat suitability in California.

    PubMed

    Zielinski, William J; Truex, Richard L; Dunk, Jeffrey R; Gaman, Tom

    2006-06-01

    The fisher (Martes pennanti) is a forest-dwelling carnivore whose current distribution and association with late-seral forest conditions make it vulnerable to stand-altering human activities or natural disturbances. Fishers select a variety of structures for daily resting bouts. These habitat elements, together with foraging and reproductive (denning) habitat, constitute the habitat requirements of fishers. We develop a model capable of predicting the suitability of fisher resting habitat using standard forest vegetation inventory data. The inventory data were derived from Forest Inventory and Analysis (FIA), a nationwide probability-based sample used to estimate forest characteristics. We developed the model by comparing vegetation and topographic data at 75 randomly selected fisher resting structures in the southern Sierra Nevada with 232 forest inventory plots. We collected vegetation data at fisher resting locations using the FIA vegetation sampling protocol and centering the 1-ha FIA plot on the resting structure. To distinguish used and available inventory plots, we used nonparametric logistic regression to evaluate a set of a priori biological models. The top model represented a dominant portion of the Akaike weights (0.87), explained 31.5% of the deviance, and included the following variables: average canopy closure, basal area of trees <51 cm diameter breast height (dbh), average hardwood dbh, maximum tree dbh, percentage slope, and the dbh of the largest conifer snag. Our use of routinely collected forest inventory data allows the assessment and monitoring of change in fisher resting habitat suitability over large regions with no additional sampling effort. Although models were constrained to include only variables available from the list of those measured using the FIA protocol, we did not find this to be a shortcoming. The model makes it possible to compare average resting habitat suitability values before and after forest management treatments, among

  15. Habitat suitability index curves for paddlefish, developed by the delphi technique

    USGS Publications Warehouse

    Crance, John H.

    1987-01-01

    A Delphi exercise conducted with a panel of 11 experts on paddlefish (Polyodon spathula) and an evaluator resulted in 14 riverine habitat suitability index curves associating various life stages or activities of paddlefish with four variables: velocity, depth, substrate type, and temperature. The panel reached a consensus on six of the curves and eight to 10 panelists agreed on the others. Several panelists reported that they found the Delphi exercise to be a good learning experience, and they believed the technique is an appropriate interim method for developing suitability index curves when available data are inadequate for more conventional statistical analyses. Documentation of good paddlefish spawning habitat was the data need most commonly identified by the panelists.

  16. Habitat evaluation using suitability index and habitat type diversity: a case study involving a shallow forest stream in central Taiwan.

    PubMed

    Chou, Wen-Chieh; Chuang, Ming-De

    2011-01-01

    In recent years, the Taiwanese government has strongly promoted the concept of ecological engineering in the hope that doing so will encourage the maintenance of the ecosystem and its integrity. As a result, the riprap spur dike is one of the most commonly used measures for protecting stream banks. Traditionally, a spur dike is used at concave banks to prevent their scouring and/or to increase their stabilization. An additional benefit of deflector structures, like spur dikes, may be to increase the weighted usable area (WUA) for aquatic life survival during periods of increased flow (examples include typhoon, flood, etc.). A two-dimensional river habitat simulation program (River2D) coupled with a developed shallow water habitat type diversity module was used for the case study at a headwater stream in central Taiwan. The habitat suitability index for this study was established using substrate, depth, and velocity from field surveys for the fish family Cyprinidae by prepositioned area electrofisher. The ungauged flood conditions were calculated using digital elevation models within a watershed delineation and hydrological modeling system in accordance with local regulations. Simulated results indicate that the spur dikes currently in use on the stream in this study need be improved from a WUA point of view more effectively handle a flood event. PMID:20376557

  17. Habitat suitability and ecological niches of different plankton functional types in the global ocean

    NASA Astrophysics Data System (ADS)

    Vogt, Meike; Brun, Philipp; Payne, Mark R.; O'Brien, Colleen J.; Bednaršek, Nina; Buitenhuis, Erik T.; Doney, Scott C.; Leblanc, Karine; Le Quéré, Corinne; Luo, Yawei; Moriarty, Róisín; O'Brien, Todd D.; Schiebel, Ralf; Swan, Chantal

    2013-04-01

    Marine plankton play a central role in the biogeochemical cycling of important elements such as carbon, nitrogen, and sulphur. While our knowledge about marine ecosystem structure and functioning is still scarce and episodic, several recent observational studies confirm that marine ecosystems have been changing due to recent climate change, overfishing, and coastal eutrophication. In order to better understand marine ecosystem dynamics, the MAREDAT initiative has recently collected abundance and biomass data for 5 autotrophic (diatoms, Phaeocystis, coccolithophores, nitrogen fixers, picophytoplankton), and 6 heterotrophic plankton functional types (PFTs; bacteria, micro-, meso- and macrozooplankton, foraminifera and pteropods). Species distribution models (SDMs) are statistical tools that can be used to derive information about species habitats in space and time. They have been used extensively for a wide range of ecological applications in terrestrial ecosystems, but here we present the first global application in the marine realm, which was made possible by the MAREDAT data synthesis effort. We use a maximum entropy SDM to simulate global habitat suitability, habitat extent and ecological niches for different PFTs in the modern ocean. Present habitat suitability is derived from presence-only MAREDAT data and the observed annual and monthly mean levels of physiologically relevant variables such as SST, nutrient concentration or photosynthetic active radiation received in the mixed layer. This information can then be used to derive ecological niches for different species or taxa within each PFT, and to compare the ecological niches of different PFTs. While these results still need verification because data was not available for all ocean regions for all PFTs, they can give a first indication what present and future plankton habitats may look like, and what consequences we may have to expect for future marine ecosystem functioning and service provision in a warmer

  18. 3-D habitat suitability of jack mackerel Trachurus murphyi in the Southeastern Pacific, a comprehensive study

    NASA Astrophysics Data System (ADS)

    Bertrand, Arnaud; Habasque, Jérémie; Hattab, Tarek; Hintzen, Niels T.; Oliveros-Ramos, Ricardo; Gutiérrez, Mariano; Demarcq, Hervé; Gerlotto, François

    2016-08-01

    South Pacific jack mackerel, Trachurus murphyi, has an ocean-scale distribution, from the South American coastline to New Zealand and Tasmania. This fish, captured by Humans since the Holocene, is nowadays heavily exploited and its population has decreased substantially since the mid-1990s. The uncertainty associated to jack mackerel population structure currently hampers management. Several hypotheses have been proposed from a single population up to several discrete populations. Still no definitive answer was given. Determining how environmental conditions drive jack mackerel distribution can provide insights on its population structure. To do so, here we performed in three steps. First, we used satellite data to develop a statistical model of jack mackerel horizontal habitat suitability. Model predictions based on interaction between temperature and chlorophyll-a match the observed jack mackerel distribution, even during extreme El Niño event. Second, we studied the impact of oxygen and show that jack mackerel distribution and abundance is correlated to oxygen over a wide variety of scales and avoid low oxygen areas and periods. Third, on the basis of the above we built a conceptual 3D model of jack mackerel habitat in the Southeastern Pacific. We reveal the presence of a low suitable habitat along the Chilean and Peruvian coast, figuratively presenting a closed door caused by a gap in the horizontal habitat at ∼19-22°S and a shallow oxycline off south-centre Peru. This kind of situation likely occurs on a seasonal basis, in austral summer but also at longer temporal scales. A lack of exchanges at some periods/seasons partially isolate jack mackerel distributed off Peru. On the other hand the continuity in the habitat during most of the year explains why exchanges occur. We conclude that the more likely population structure for jack mackerel is a pelagic metapopulation.

  19. Using habitat suitability index and particle dispersion models for early detection of marine invaders.

    PubMed

    Inglis, Graeme J; Hurren, Helen; Oldman, John; Haskew, Rachel

    2006-08-01

    Eradication and control of invasive species are often possible only if populations are detected when they are small and localized. To be efficient, detection surveys should be targeted at locations where there is the greatest risk of incursions. We examine the utility of habitat suitability index (HSI) and particle dispersion models for targeting sampling for marine pests. Habitat suitability index models are a simple way to identify suitable habitat when species distribution data are lacking. We compared the performance of HSI models with statistical models derived from independent data from New Zealand on the distribution of two nonindigenous bivalves: Theora lubrica and Musculista senhousia. Logistic regression models developed using the HSI scores as predictors of the presence/absence of Theora and Musculista explained 26.7% and 6.2% of the deviance in the data, respectively. Odds ratios for the HSI scores were greater than unity, indicating that they were genuine predictors of the presence/ absence of each species. The fit and predictive accuracy of each logistic model were improved when simulated patterns of dispersion from the nearest port were added as a predictor variable. Nevertheless, the combined model explained, at best, 46.5% of the deviance in the distribution of Theora and correctly predicted 56% of true presences and 50% of all cases. Omission errors were between 6% and 16%. Although statistical distribution models built directly from environmental predictors always outperformed the equivalent HSI models, the gain in model fit and accuracy was modest. High residual deviance in both types of model suggests that the distributions realized by Theora and Musculista in the field data were influenced by factors not explicitly modeled as explanatory variables and by error in the environmental data used to project suitable habitat for the species. Our results highlight the difficulty of accurately predicting the distribution of invasive marine species that

  20. Global Habitat Suitability and Ecological Niche Separation in the Phylum Placozoa.

    PubMed

    Paknia, Omid; Schierwater, Bernd

    2015-01-01

    The enigmatic placozoans, which hold a key position in the metazoan Tree of Life, have attracted substantial attention in many areas of biological and biomedical research. While placozoans have become an emerging model system, their ecology and particularly biogeography remain widely unknown. In this study, we use modelling approaches to explore habitat preferences, and distribution pattern of the placozoans phylum. We provide hypotheses for discrete ecological niche separation between genetic placozoan lineages, which may also help to understand biogeography patterns in other small marine invertebrates. We, here, used maximum entropy modelling to predict placozoan distribution using 20 environmental grids of 9.2 km2 resolution. In addition, we used recently developed metrics of niche overlap to compare habitat suitability models of three genetic clades. The predicted distributions range from 55°N to 44°S and are restricted to regions of intermediate to warm sea surface temperatures. High concentrations of salinity and low nutrient concentrations appear as secondary factors. Tests of niche equivalency reveal the largest differences between placozoan clades I and III. Interestingly, the genetically well-separated clades I and V appear to be ecologically very similar. Our habitat suitability models predict a wider latitudinal distribution for placozoans, than currently described, especially in the northern hemisphere. With respect to biogeography modelling, placozoans show patterns somewhere between higher metazoan taxa and marine microorganisms, with the first group usually showing complex biogeographies and the second usually showing "no biogeography." PMID:26580806

  1. Quantifying Florida Bay Habitat Suitability for Fishes and Invertebrates Under Climate Change Scenarios

    NASA Astrophysics Data System (ADS)

    Kearney, Kelly A.; Butler, Mark; Glazer, Robert; Kelble, Christopher R.; Serafy, Joseph E.; Stabenau, Erik

    2015-04-01

    The Florida Bay ecosystem supports a number of economically important ecosystem services, including several recreational fisheries, which may be affected by changing salinity and temperature due to climate change. In this paper, we use a combination of physical models and habitat suitability index models to quantify the effects of potential climate change scenarios on a variety of juvenile fish and lobster species in Florida Bay. The climate scenarios include alterations in sea level, evaporation and precipitation rates, coastal runoff, and water temperature. We find that the changes in habitat suitability vary in both magnitude and direction across the scenarios and species, but are on average small. Only one of the seven species we investigate ( Lagodon rhomboides, i.e., pinfish) sees a sizable decrease in optimal habitat under any of the scenarios. This suggests that the estuarine fauna of Florida Bay may not be as vulnerable to climate change as other components of the ecosystem, such as those in the marine/terrestrial ecotone. However, these models are relatively simplistic, looking only at single species effects of physical drivers without considering the many interspecific interactions that may play a key role in the adjustment of the ecosystem as a whole. More complex models that capture the mechanistic links between physics and biology, as well as the complex dynamics of the estuarine food web, may be necessary to further understand the potential effects of climate change on the Florida Bay ecosystem.

  2. Quantifying Florida Bay habitat suitability for fishes and invertebrates under climate change scenarios.

    PubMed

    Kearney, Kelly A; Butler, Mark; Glazer, Robert; Kelble, Christopher R; Serafy, Joseph E; Stabenau, Erik

    2015-04-01

    The Florida Bay ecosystem supports a number of economically important ecosystem services, including several recreational fisheries, which may be affected by changing salinity and temperature due to climate change. In this paper, we use a combination of physical models and habitat suitability index models to quantify the effects of potential climate change scenarios on a variety of juvenile fish and lobster species in Florida Bay. The climate scenarios include alterations in sea level, evaporation and precipitation rates, coastal runoff, and water temperature. We find that the changes in habitat suitability vary in both magnitude and direction across the scenarios and species, but are on average small. Only one of the seven species we investigate (Lagodon rhomboides, i.e., pinfish) sees a sizable decrease in optimal habitat under any of the scenarios. This suggests that the estuarine fauna of Florida Bay may not be as vulnerable to climate change as other components of the ecosystem, such as those in the marine/terrestrial ecotone. However, these models are relatively simplistic, looking only at single species effects of physical drivers without considering the many interspecific interactions that may play a key role in the adjustment of the ecosystem as a whole. More complex models that capture the mechanistic links between physics and biology, as well as the complex dynamics of the estuarine food web, may be necessary to further understand the potential effects of climate change on the Florida Bay ecosystem. PMID:25216988

  3. Global Habitat Suitability and Ecological Niche Separation in the Phylum Placozoa

    PubMed Central

    Paknia, Omid; Schierwater, Bernd

    2015-01-01

    The enigmatic placozoans, which hold a key position in the metazoan Tree of Life, have attracted substantial attention in many areas of biological and biomedical research. While placozoans have become an emerging model system, their ecology and particularly biogeography remain widely unknown. In this study, we use modelling approaches to explore habitat preferences, and distribution pattern of the placozoans phylum. We provide hypotheses for discrete ecological niche separation between genetic placozoan lineages, which may also help to understand biogeography patterns in other small marine invertebrates. We, here, used maximum entropy modelling to predict placozoan distribution using 20 environmental grids of 9.2 km2 resolution. In addition, we used recently developed metrics of niche overlap to compare habitat suitability models of three genetic clades. The predicted distributions range from 55°N to 44°S and are restricted to regions of intermediate to warm sea surface temperatures. High concentrations of salinity and low nutrient concentrations appear as secondary factors. Tests of niche equivalency reveal the largest differences between placozoan clades I and III. Interestingly, the genetically well-separated clades I and V appear to be ecologically very similar. Our habitat suitability models predict a wider latitudinal distribution for placozoans, than currently described, especially in the northern hemisphere. With respect to biogeography modelling, placozoans show patterns somewhere between higher metazoan taxa and marine microorganisms, with the first group usually showing complex biogeographies and the second usually showing “no biogeography.” PMID:26580806

  4. A Habitat Suitability Model for Selected Crayfish Species in Lancaster County,Pennsylvania, Streams

    NASA Astrophysics Data System (ADS)

    Laverty, S.; Buchanan, R.; Wagner, J.; Wallace, J.; Perry, B.

    2005-05-01

    The introduction of invasive exotic species to previously inaccessible areas provides the opportunity to study the impacts of invasive species on closely related native species. Habitat suitability index [HSI] models offer a coarse estimate of the habitat quality relative to hypothesized physiological tolerances of a species. The distribution and abundance of two native [Orconectes obscurus and Cambarus bartonii] and one invasive [Orconectes rusticus] crayfish along a twenty-three mile length of a Lancaster County, PA, stream and various physical factors at the sample sites were provided by a recent survey (Wagner et.al. unpublished). Of the factors provided, stream width, velocity, pH, and temperature were considered as the factors defining the geographic range of each species. An HSI model was constructed based on these factors to identify regions offering suitable habitat for a species and areas of a stream which are at risk for invasion of O. rusticus. Current work involves the development of subindices describing the availability of food and shelter within the stream, using stream order, link magnitude, and substrate measurements. The HSI model will be coupled to a model describing the interactions between size-structured populations of native and invasive species under the influence of a predator.

  5. Are mountain habitats becoming more suitable for generalist than cold-adapted lizards thermoregulation?

    PubMed Central

    Mencía, Abraham; Pérez-Mellado, Valentín

    2016-01-01

    Mountain lizards are highly vulnerable to climate change, and the continuous warming of their habitats could be seriously threatening their survival. We aim to compare the thermal ecology and microhabitat selection of a mountain lizard, Iberolacerta galani, and a widely distributed lizard, Podarcis bocagei, in a montane area. Both species are currently in close syntopy in the study area, at 1,400 m above the sea level. We determined the precision, accuracy and effectiveness of thermoregulation, and the thermal quality of habitat for both species. We also compared the selection of thermal microhabitats between both species. Results show that I. galani is a cold-adapted thermal specialist with a preferred temperature range of 27.9–29.7 °C, while P. bocagei would be a thermal generalist, with a broader and higher preferred temperature range (30.1–34.5 °C). In addition, I. galani selects rocky substrates while P. bocagei selects warmer soil and leaf litter substrates. The thermal quality of the habitat is higher for P. bocagei than for I. galani. Finally, P. bocagei achieves a significantly higher effectiveness of thermoregulation (0.87) than I. galani (0.80). Therefore, these mountain habitat conditions seem currently more suitable for performance of thermophilic generalist lizards than for cold-specialist lizards. PMID:27280076

  6. Assessing current and projected suitable habitats for tree-of-heaven along the Appalachian Trail

    PubMed Central

    Clark, John; Wang, Yeqiao; August, Peter V.

    2014-01-01

    The invasion of ecosystems by non-native species is a major driver of biodiversity loss worldwide. A critical component of effective land management to control invasion is the identification and active protection of areas at high risk of future invasion. The Appalachian Trail Decision Support System (A.T.-DSS) was developed to inform regional natural resource management by integrating remote sensing data, ground-based measurements and predictive modelling products. By incorporating NASA's remote sensing data and modelling capacities from the Terrestrial Observation and Prediction System (TOPS), this study examined the current habitat suitability and projected suitable habitat for the invasive species tree-of-heaven (Ailanthus altissima) as a prototype application of the A.T.-DSS. Species observations from forest surveys, geospatial data, climatic projections and maximum entropy modelling were used to identify regions potentially susceptible to tree-of-heaven invasion. The modelling result predicted a 48% increase in suitable area over the study area, with significant expansion along the northern extremes of the Appalachian Trail. PMID:24733947

  7. Assessing current and projected suitable habitats for tree-of-heaven along the Appalachian Trail.

    PubMed

    Clark, John; Wang, Yeqiao; August, Peter V

    2014-01-01

    The invasion of ecosystems by non-native species is a major driver of biodiversity loss worldwide. A critical component of effective land management to control invasion is the identification and active protection of areas at high risk of future invasion. The Appalachian Trail Decision Support System (A.T.-DSS) was developed to inform regional natural resource management by integrating remote sensing data, ground-based measurements and predictive modelling products. By incorporating NASA's remote sensing data and modelling capacities from the Terrestrial Observation and Prediction System (TOPS), this study examined the current habitat suitability and projected suitable habitat for the invasive species tree-of-heaven (Ailanthus altissima) as a prototype application of the A.T.-DSS. Species observations from forest surveys, geospatial data, climatic projections and maximum entropy modelling were used to identify regions potentially susceptible to tree-of-heaven invasion. The modelling result predicted a 48% increase in suitable area over the study area, with significant expansion along the northern extremes of the Appalachian Trail. PMID:24733947

  8. Assessment of suitable habitat for Phragmites australis (common reed) in the Great Lakes coastal zone

    USGS Publications Warehouse

    Carlson Mazur, Martha L.; Kowalski, Kurt P.; Galbraith, David

    2014-01-01

    In the Laurentian Great Lakes, the invasive form of Phragmites australis (common reed) poses a threat to highly productive coastal wetlands and shorelines by forming impenetrable stands that outcompete native plants. Large, dominant stands can derail efforts to restore wetland ecosystems degraded by other stressors. To be proactive, landscape-level management of Phragmites requires information on the current spatial distribution of the species and a characterization of areas suitable for future colonization. Using a recent basin-scale map of this invasive plant’s distribution in the U.S. coastal zone of the Great Lakes, environmental data (e.g., soils, nutrients, disturbance, climate, topography), and climate predictions, we performed analyses of current and predicted suitable coastal habitat using boosted regression trees, a type of species distribution modeling. We also investigated differential influences of environmental variables in the upper lakes (Lakes Superior, Michigan, and Huron) and lower lakes (Lakes St. Clair, Erie, and Ontario). Basin-wide results showed that the coastal areas most vulnerable to Phragmites expansion were in close proximity to developed lands and had minimal topographic relief, poorly drained soils, and dense road networks. Elevated nutrients and proximity to agriculture also influenced the distribution of Phragmites. Climate predictions indicated an increase in suitable habitat in coastal Lakes Huron and Michigan in particular. The results of this study, combined with a publicly available online decision support tool, will enable resource managers and restoration practitioners to target and prioritize Phragmites control efforts in the Great Lakes coastal zone.

  9. Hyperspectral Mapping of the Invasive Species Pepperweed and the Development of a Habitat Suitability Model

    NASA Astrophysics Data System (ADS)

    Nguyen, A.; Gole, A.; Randall, J.; Dlott, G. A.; Zhang, S.; Alfaro, B.; Schmidt, C.; Skiles, J. W.

    2011-12-01

    Mapping and predicting the spatial distribution of invasive plant species is central to habitat management, however difficult to implement at landscape and regional scales. Remote sensing techniques can reduce the cost of field campaigns and can provide a regional and multi-temporal view of invasive species spread. Invasive perennial pepperweed (Lepidium latifolium) is now widespread in fragmented estuaries of the South San Francisco Bay, and is shown to degrade native vegetation in estuaries and adjacent habitats, thereby reducing forage and shelter for wildlife. The purpose of this study is to map the current distribution of pepperweed in estuarine areas of the South San Francisco Bay Salt Pond Restoration Project, and create a habitat suitability model to predict future spread. Pepperweed reflectance data were collected in-situ with a GER 1500 spectroradiometer along with 88 corresponding pepperweed presence and absence points used for building the statistical models. The spectral angle mapper (SAM) classification algorithm was used to distinguish the reflectance spectrum of pepperweed and map its distribution using an EO-1 Hyperion satellite image. To map pepperweed, a supervised classification was performed on an ASTER image with a resulting classification accuracy of 71.8%. We generated a weighted overlay analysis model within a geographic information system (GIS) framework to predict areas in the study site most susceptible to pepperweed colonization. Variables for the model included propensity for disturbance, status of pond restoration, proximity to water channels, and terrain curvature. A Generalized Additive Model (GAM) was also used to generate a probability map and investigate the statistical probability that each variable contributed to predict pepperweed spread. Results from the GAM revealed distance to channels, distance to ponds and curvature were statistically significant (p < 0.01) in determining the locations of suitable pepperweed habitats.

  10. Hyperspectral Mapping of the Invasive Species Pepperweed and the Development of a Habitat Suitability Model

    NASA Technical Reports Server (NTRS)

    Nguyen, Andrew; Gole, Alexander; Randall, Jarom; Dlott, Glade; Zhang, Sylvia; Alfaro, Brian; Schmidt, Cindy; Skiles, J. W.

    2011-01-01

    Mapping and predicting the spatial distribution of invasive plant species is central to habitat management, however difficult to implement at landscape and regional scales. Remote sensing techniques can reduce the impact field campaigns have on these ecologically sensitive areas and can provide a regional and multi-temporal view of invasive species spread. Invasive perennial pepperweed (Lepidium latifolium) is now widespread in fragmented estuaries of the South San Francisco Bay, and is shown to degrade native vegetation in estuaries and adjacent habitats, thereby reducing forage and shelter for wildlife. The purpose of this study is to map the present distribution of pepperweed in estuarine areas of the South San Francisco Bay Salt Pond Restoration Project (Alviso, CA), and create a habitat suitability model to predict future spread. Pepperweed reflectance data were collected in-situ with a GER 1500 spectroradiometer along with 88 corresponding pepperweed presence and absence points used for building the statistical models. The spectral angle mapper (SAM) classification algorithm was used to distinguish the reflectance spectrum of pepperweed and map its distribution using an image from EO-1 Hyperion. To map pepperweed, we performed a supervised classification on an ASTER image with a resulting classification accuracy of 71.8%. We generated a weighted overlay analysis model within a geographic information system (GIS) framework to predict areas in the study site most susceptible to pepperweed colonization. Variables for the model included propensity for disturbance, status of pond restoration, proximity to water channels, and terrain curvature. A Generalized Additive Model (GAM) was also used to generate a probability map and investigate the statistical probability that each variable contributed to predict pepperweed spread. Results from the GAM revealed distance to channels, distance to ponds and curvature were statistically significant (p < 0.01) in determining

  11. Changing land use and its impact on the habitat suitability for wintering Anseriformes in China's Poyang Lake region.

    PubMed

    Tang, Xuguang; Li, Hengpeng; Xu, Xibao; Yang, Guishan; Liu, Guihua; Li, Xinyan; Chen, Dongqiang

    2016-07-01

    As an internationally important wetland for migratory waterbirds, China's Poyang Lake region has experienced substantial changes in land use during the past two decades owing to climate change and anthropogenic disturbances. Recent dam constructions on the Yangtze River and its tributaries for agriculture and hydroelectric power exert strong effects on the hydrological regimes of this lake. However, few studies have investigated how the land-use changes through time affect the habitat suitability for wintering Anseriformes-the largest community in this region. Thus, it is necessary to timely monitor changes in the habitat quality and understand the potential factors that alter it. In this study, three periods (1995, 2005 and 2014) of typical environmental indicators that have direct impacts on foraging and resting for the Anserformes, including proximity to water (density of lakes, rivers and ponds), human disturbances (density of residences and various road networks), preferred land cover types and food availability (NDVI), are integrated to develop a habitat suitability index model for habitat mapping. The results indicate that long-term lake shrinkage in low-water periods led to greatly expanded wetlands in these years, which provided more suitable habitat for migratory waterfowl. The amount of highly suitable habitat in 2014 was nearly twice as much as in 1995. Recent survey data from 1997 to 2013 also revealed an increase in the population size, and confirmed the improvement of habitat suitability in the Poyang Lake region. Spatial analysis revealed that land use changes contributed most to the improved habitat coverage between 1995 and 2014. However, the relative significances of these transformations for highly suitable and moderately suitable habitats are strikingly different. Increases in wetland and paddy field area are the main reasons for explaining these improvements, respectively. The framework model proposed in this study will help governments to

  12. [Identification and conservation assessment of suitable habitats for Tibetan antelope in the alpine desert, Qinghai-Tibet Plateau].

    PubMed

    Zhuge, Hai-jin; Li, Xiao-wen; Zhang, Xiang; Gao, Feng; Xu, Dong-hua

    2014-12-01

    As a flagship and one of most endangered ungulates in the alpine desert of Qinghai-Tibet Plateau, the habitat conservation of Tibetan antelope (Pantholops hodgsonii) is vital to sustain its long-term population existence. In consideration of key habitat factors of the Tibetan antelope (i.e., food, topography and water source) as well as human interference factors like roads and settlements, the habitat suitability was modeled, and potential and valid suitable habitats were identified for Tibetan antelope in the alpine desert, Qinghai-Tibet Plateau. Furthermore, the conservation proportion index and conservation efficacy index were developed to facilitate the conservation assessment of three national reserves (i.e., Altun Mountain, Kekexili and Qiangtang) and their associated functional zones in the study area. The results showed that potential and valid area of suitable habitat across overall study area were 2.84 x 10(5) and 2.08 x 10(5) km2 respectively, with 16.1% of suitable habitat loss by human disturbance. At reserve level, the potential suitable habitats of Altun Mountain, Kekexili and Qiangtang were 2.01 x 10(4), 3.13 x 104 and 1.26 x 10(5) km2, which however decreased by 12.9%, 10.2% and 21.1% human disturbance respectively, indicating a prominent habitat fragmentation especially in Qiangtang National Nature Reserve (NNR). Although three NNRs had captured nearly 2/3 of the potential/valid suitable habitats with favorable conservation efficacy, there were still obvious conservation gaps outside the existing reserve network. At the functional zone level, buffer and experimental zones also showed significant conservation proportion and efficacy besides the core zone. Our research highlighted the necessity to optimize the existing re serve system by filling the conservation gaps, restructuring the functional zones and safeguarding the potential refuge habitats for those endangered ungulates in face of climate change. PMID:25876398

  13. Global Decline in Suitable Habitat for Angiostrongylus ( = Parastrongylus) cantonensis: The Role of Climate Change

    PubMed Central

    York, Emily M.; Butler, Christopher J.; Lord, Wayne D.

    2014-01-01

    Climate change is implicated in the alteration of the ranges of species worldwide. Such shifts in species distributions may introduce parasites/pathogens, hosts, and vectors associated with disease to new areas. The parasite Angiostrongylus ( = Parastrongylus) cantonensis is an invasive species that causes eosinophilic meningitis in humans and neurological abnormalities in domestic/wild animals. Although native to southeastern Asia, A. cantonensis has now been reported from more than 30 countries worldwide. Given the health risks, it is important to describe areas with potentially favorable climate for the establishment of A. cantonensis, as well as areas where this pathogen might become established in the future. We used the program Maxent to develop an ecological niche model for A. cantonensis based on 86 localities obtained from published literature. We then modeled areas of potential A. cantonensis distribution as well as areas projected to have suitable climatic conditions under four Representative Concentration Pathways (RCP) scenarios by the 2050s and the 2070s. The best model contained three bioclimatic variables: mean diurnal temperature range, minimum temperature of coldest month and precipitation of warmest quarter. Potentially suitable habitat for A. cantonensis was located worldwide in tropical and subtropical regions. Under all climate change RCP scenarios, the center of the projected distribution shifted away from the equator at a rate of 68–152 km per decade. However, the extent of areas with highly suitable habitat (>50%) declined by 10.66–15.66% by the 2050s and 13.11–16.11% by the 2070s. These results conflict with previous studies, which have generally found that the prevalence of tropical pathogens will increase during the 21st century. Moreover, it is likely that A. cantonensis will continue to expand its current range in the near future due to introductions and host expansion, whereas climate change will reduce the total geographic

  14. Modeling habitat suitability for complex species distributions by environmental-distance geometric mean.

    PubMed

    Hirzel, Alexandre H; Arlettaz, Raphaël

    2003-11-01

    This paper presents a new habitat suitability modeling method whose main properties are as follows: (1) It is based on the density of observation points in the environmental space, which enables it to fit complex distributions (e.g. nongaussian, bimodal, asymmetrical, etc.). (2) This density is modeled by computing the geometric mean to all observation points, which we show to be a good trade-off between goodness of fit and prediction power. (3) It does not need any absence information, which is generally difficult to collect and of dubious reliability. (4) The environmental space is represented either by an expert-selection of standardized variables or the axes of a factor analysis [in this paper we used the Ecological Niche Factor Analysis (ENFA)]. We first explain the details of the geometric mean algorithm and then we apply it to the bearded vulture (Gypaetus barbatus) habitat in the Swiss Alps. The results are compared to those obtained by the "median algorithm" and tested by jack-knife cross-validation. We also discuss other related algorithms (BIOCLIM, HABITAT, and DOMAIN). All these analyses were implemented into and performed with the ecology-oriented GIS software BIOMAPPER 2.0.The results show the geometric mean to perform better than the median algorithm, as it produces a tighter fit to the bimodal distribution of the bearded vulture in the environmental space. However, the "median algorithm" being quicker, it could be preferred when modeling more usual distribution. PMID:15015699

  15. Habitat suitability of the Wadden Sea for restoration of Zostera marina beds

    NASA Astrophysics Data System (ADS)

    van Katwijk, M. M.; Hermus, D. C. R.; de Jong, D. J.; Asmus, R. M.; de Jonge, V. N.

    2000-07-01

    A conceptual model is proposed, describing potential Zostera marina habitats in the Wadden Sea, based on reported data from laboratory, mesocosm and field studies. Controlling factors in the model are dynamics, degree of desiccation, turbidity, nutrients and salinity. A distinction has been made between a higher and a lower zone of potential habitats, each suitable for different morphotypes of Z. marina. The model relates the decline of Z. marina in the Wadden Sea to increased sediment and water dynamics, turbidity, drainage of sediments (resulting in increased degree of desiccation) and total nutrient loads during the twentieth century. The upper and lower delineation of both the higher and the lower zone of potential Z. marina habitats appear to be determined by one or a combination of several of these factors. Environmental changes in one of these factors will therefore influence the borderlines of the zones. The lower zone of Z. marina will be mainly affected by increased turbidity, sediment dynamics, degree of desiccation during low tide and nutrient load. The higher zone will be affected by increases in water and sediment dynamics, desiccation rates and nutrient loads. Potential Z. marina habitats are located above approx. -0.80 m mean sea level (when turbidity remains at the same level as in the early 1990s) in sheltered, undisturbed locations, and preferably where some freshwater influence is present. At locations with a high, near-marine, salinity, the nutrient load has to be low to allow the growth of Z. marina. The sediment should retain enough water during low tide to keep the plants moist. Our results suggest that the return of Z. marina beds within a reasonable time-scale will require not only suitable habitat conditions, but also revegetation measures, as the changes in the environment resulting from the disappearance of Z. marina may impede its recovery, and the natural import of propagules will be unlikely. Furthermore, the lower zone of Z. marina

  16. Upward Altitudinal Shifts in Habitat Suitability of Mountain Vipers since the Last Glacial Maximum

    PubMed Central

    Yousefi, Masoud; Ahmadi, Mohsen; Nourani, Elham; Behrooz, Roozbeh; Rajabizadeh, Mehdi; Geniez, Philippe; Kaboli, Mohammad

    2015-01-01

    We determined the effects of past and future climate changes on the distribution of the Montivipera raddei species complex (MRC) that contains rare and endangered viper species limited to Iran, Turkey and Armenia. We also investigated the current distribution of MRC to locate unidentified isolated populations as well as to evaluate the effectiveness of the current network of protected areas for their conservation. Present distribution of MRC was modeled based on ecological variables and model performance was evaluated by field visits. Some individuals at the newly identified populations showed uncommon morphological characteristics. The distribution map of MRC derived through modeling was then compared with the distribution of protected areas in the region. We estimated the effectiveness of the current protected area network to be 10%, which would be sufficient for conserving this group of species, provided adequate management policies and practices are employed. We further modeled the distribution of MRC in the past (21,000 years ago) and under two scenarios in the future (to 2070). These models indicated that climatic changes probably have been responsible for an upward shift in suitable habitats of MRC since the Last Glacial Maximum, leading to isolation of allopatric populations. Distribution will probably become much more restricted in the future as a result of the current rate of global warming. We conclude that climate change most likely played a major role in determining the distribution pattern of MRC, restricting allopatric populations to mountaintops due to habitat alterations. This long-term isolation has facilitated unique local adaptations among MRC populations, which requires further investigation. The suitable habitat patches identified through modeling constitute optimized solutions for inclusion in the network of protected areas in the region. PMID:26367126

  17. Upward Altitudinal Shifts in Habitat Suitability of Mountain Vipers since the Last Glacial Maximum.

    PubMed

    Yousefi, Masoud; Ahmadi, Mohsen; Nourani, Elham; Behrooz, Roozbeh; Rajabizadeh, Mehdi; Geniez, Philippe; Kaboli, Mohammad

    2015-01-01

    We determined the effects of past and future climate changes on the distribution of the Montivipera raddei species complex (MRC) that contains rare and endangered viper species limited to Iran, Turkey and Armenia. We also investigated the current distribution of MRC to locate unidentified isolated populations as well as to evaluate the effectiveness of the current network of protected areas for their conservation. Present distribution of MRC was modeled based on ecological variables and model performance was evaluated by field visits. Some individuals at the newly identified populations showed uncommon morphological characteristics. The distribution map of MRC derived through modeling was then compared with the distribution of protected areas in the region. We estimated the effectiveness of the current protected area network to be 10%, which would be sufficient for conserving this group of species, provided adequate management policies and practices are employed. We further modeled the distribution of MRC in the past (21,000 years ago) and under two scenarios in the future (to 2070). These models indicated that climatic changes probably have been responsible for an upward shift in suitable habitats of MRC since the Last Glacial Maximum, leading to isolation of allopatric populations. Distribution will probably become much more restricted in the future as a result of the current rate of global warming. We conclude that climate change most likely played a major role in determining the distribution pattern of MRC, restricting allopatric populations to mountaintops due to habitat alterations. This long-term isolation has facilitated unique local adaptations among MRC populations, which requires further investigation. The suitable habitat patches identified through modeling constitute optimized solutions for inclusion in the network of protected areas in the region. PMID:26367126

  18. Assessment of Effectiveness and Limitations of Habitat Suitability Models for Wetland Restoration

    USGS Publications Warehouse

    Draugelis-Dale, Rassa O.

    2008-01-01

    Habitat suitability index (HSI) models developed for wildlife in the Louisiana Coastal Area Comprehensive Ecosystem Restoration Plan (LCA study) have been assessed for parameter and overall model quality. The success of the suitability models from the South Florida Water Management District for The Everglades restoration project and from the Spatially Explicit Species Index Models (SESI) of the Across Trophic Level System Simulation (ATLSS) Program of Florida warranted investigation with possible application of modeling theory to the current LCA study. General HSI models developed by the U.S. Fish and Wildlife Service were also investigated. This report presents examinations of theoretical formulae and comparisons of the models, performed by using diverse hypothetical settings of hydrological/biological ecosystems to highlight weaknesses as well as strengths among the models, limited to the American alligator and selected wading bird species (great blue heron, great egret, and white ibis). Recommendations were made for the LCA study based on these assessments. An enhanced HSI model for the LCA study is proposed for the American alligator, and a new HSI model for wading birds is introduced for the LCA study. Performance comparisons of the proposed models with the other suitability models are made by using the aforementioned hypothetical settings.

  19. Evaluating Habitat Suitability for the Establishment of Monochamus spp. through Climate-Based Niche Modeling

    PubMed Central

    Estay, Sergio A.; Labra, Fabio A.; Sepulveda, Roger D.; Bacigalupe, Leonardo D.

    2014-01-01

    Pine sawyer beetle species of the genus Monochamus are vectors of the nematode pest Bursaphelenchus xylophilus. The introduction of these species into new habitats is a constant threat for those regions where the forestry industry depends on conifers, and especially on species of Pinus. To obtain information about the potential risk of establishment of these insects in Chile, we performed climate-based niche modeling using data for five North American and four Eurasian Monochamus species using a Maxent approach. The most important variables that account for current distribution of these species are total annual precipitation and annual and seasonal average temperatures, with some differences between North American and Eurasian species. Projections of potential geographic distribution in Chile show that all species could occupy at least 37% of the area between 30° and 53°S, where industrial plantations of P. radiata are concentrated. Our results indicated that Chile seems more suitable for Eurasian than for North American species. PMID:25019408

  20. Evaluating habitat suitability for the establishment of Monochamus spp. through climate-based niche modeling.

    PubMed

    Estay, Sergio A; Labra, Fabio A; Sepulveda, Roger D; Bacigalupe, Leonardo D

    2014-01-01

    Pine sawyer beetle species of the genus Monochamus are vectors of the nematode pest Bursaphelenchus xylophilus. The introduction of these species into new habitats is a constant threat for those regions where the forestry industry depends on conifers, and especially on species of Pinus. To obtain information about the potential risk of establishment of these insects in Chile, we performed climate-based niche modeling using data for five North American and four Eurasian Monochamus species using a Maxent approach. The most important variables that account for current distribution of these species are total annual precipitation and annual and seasonal average temperatures, with some differences between North American and Eurasian species. Projections of potential geographic distribution in Chile show that all species could occupy at least 37% of the area between 30° and 53°S, where industrial plantations of P. radiata are concentrated. Our results indicated that Chile seems more suitable for Eurasian than for North American species. PMID:25019408

  1. Habitat suitability criteria via parametric distributions: estimation, model selection and uncertainty

    USGS Publications Warehouse

    Som, Nicholas A.; Goodman, Damon H.; Perry, Russell W.; Hardy, Thomas B.

    2015-01-01

    Previous methods for constructing univariate habitat suitability criteria (HSC) curves have ranged from professional judgement to kernel-smoothed density functions or combinations thereof. We present a new method of generating HSC curves that applies probability density functions as the mathematical representation of the curves. Compared with previous approaches, benefits of our method include (1) estimation of probability density function parameters directly from raw data, (2) quantitative methods for selecting among several candidate probability density functions, and (3) concise methods for expressing estimation uncertainty in the HSC curves. We demonstrate our method with a thorough example using data collected on the depth of water used by juvenile Chinook salmon (Oncorhynchus tschawytscha) in the Klamath River of northern California and southern Oregon. All R code needed to implement our example is provided in the appendix. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

  2. Predicting suitable habitat for the cold-water coral Lophelia pertusa (Scleractinia)

    NASA Astrophysics Data System (ADS)

    Davies, Andrew J.; Wisshak, Max; Orr, James C.; Murray Roberts, J.

    2008-08-01

    Ecological-niche factor analysis (ENFA) was applied to the reef framework-forming cold-water coral Lophelia pertusa. The environmental tolerances of this species were assessed using readily available oceanographic data, including physical, chemical, and biological variables. L. pertusa was found at mean depths of 468 and 480 m on the regional and global scales and occupied a niche that included higher than average current speed and productivity, supporting the theory that their limited food supply is locally enhanced by currents. Most records occurred in areas with a salinity of 35, mean temperatures of 6.2-6.7 °C and dissolved oxygen levels of 6.0-6.2 ml l -1. The majority of records were found in areas that were saturated with aragonite but had low concentration of nutrients (silicate, phosphate, and nitrate). Suitable habitat for L. pertusa was predicted using ENFA on a global and a regional scale that incorporated the north-east Atlantic Ocean. Regional prediction was reliable due to numerous presence points throughout the area, whereas global prediction was less reliable due to the paucity of presence data outside of the north-east Atlantic. However, the species niche was supported at each spatial scale. Predicted maps at the global scale reinforced the general consensus that the North Atlantic Ocean is a key region in the worldwide distribution of L. pertusa. Predictive modelling is an approach that can be applied to cold-water coral species to locate areas of suitable habitat for further study. It may also prove a useful tool to assist spatial planning of offshore marine protected areas. However, issues with eco-geographical datasets, including their coarse resolution and limited geographical coverage, currently restrict the scope of this approach.

  3. Evaluation of Limiting Climatic Factors and Simulation of a Climatically Suitable Habitat for Chinese Sea Buckthorn.

    PubMed

    Li, Guoqing; Du, Sheng; Guo, Ke

    2015-01-01

    Chinese sea buckthorn (Hippophae rhamnoides subsp. sinensis) has considerable economic potential and plays an important role in reclamation and soil and water conservation. For scientific cultivation of this species across China, we identified the key climatic factors and explored climatically suitable habitat in order to maximize survival of Chinese sea buckthorn using MaxEnt and GIS tools, based on 98 occurrence records from herbarium and publications and 13 climatic factors from Bioclim, Holdridge life zone and Kria' index variables. Our simulation showed that the MaxEnt model performance was significantly better than random, with an average test AUC value of 0.93 with 10-fold cross validation. A jackknife test and the regularized gain change, which were applied to the training algorithm, showed that precipitation of the driest month (PDM), annual precipitation (AP), coldness index (CI) and annual range of temperature (ART) were the most influential climatic factors in limiting the distribution of Chinese sea buckthorn, which explained 70.1% of the variation. The predicted map showed that the core of climatically suitable habitat was distributed from the southwest to northwest of Gansu, Ningxia, Shaanxi and Shanxi provinces, where the most influential climate variables were PDM of 1.0-7.0 mm, AP of 344.0-1089.0 mm, CI of -47.7-0.0°C, and ART of 26.1-45.0°C. We conclude that the distribution patterns of Chinese sea buckthorn are related to the northwest winter monsoon, the southwest summer monsoon and the southeast summer monsoon systems in China. PMID:26177033

  4. Evaluation of Limiting Climatic Factors and Simulation of a Climatically Suitable Habitat for Chinese Sea Buckthorn

    PubMed Central

    Li, Guoqing; Du, Sheng; Guo, Ke

    2015-01-01

    Chinese sea buckthorn (Hippophae rhamnoides subsp. sinensis) has considerable economic potential and plays an important role in reclamation and soil and water conservation. For scientific cultivation of this species across China, we identified the key climatic factors and explored climatically suitable habitat in order to maximize survival of Chinese sea buckthorn using MaxEnt and GIS tools, based on 98 occurrence records from herbarium and publications and 13 climatic factors from Bioclim, Holdridge life zone and Kria' index variables. Our simulation showed that the MaxEnt model performance was significantly better than random, with an average test AUC value of 0.93 with 10-fold cross validation. A jackknife test and the regularized gain change, which were applied to the training algorithm, showed that precipitation of the driest month (PDM), annual precipitation (AP), coldness index (CI) and annual range of temperature (ART) were the most influential climatic factors in limiting the distribution of Chinese sea buckthorn, which explained 70.1% of the variation. The predicted map showed that the core of climatically suitable habitat was distributed from the southwest to northwest of Gansu, Ningxia, Shaanxi and Shanxi provinces, where the most influential climate variables were PDM of 1.0–7.0 mm, AP of 344.0–1089.0 mm, CI of -47.7–0.0°C, and ART of 26.1–45.0°C. We conclude that the distribution patterns of Chinese sea buckthorn are related to the northwest winter monsoon, the southwest summer monsoon and the southeast summer monsoon systems in China. PMID:26177033

  5. Tree colonization by the Asian longhorn beetle, Anoplophora glabripennis (Coleoptera: Cerambycidae): effect of habitat and tree suitability.

    PubMed

    Faccoli, Massimo; Favaro, Riccardo; Concheri, Giuseppe; Squartini, Andrea; Battisti, Andrea

    2016-04-01

    Tree colonization and feeding activity of the invasive wood-borer Asian longhorn beetle (Anoplophora glabripennis), an Asian pest introduced into North America and Europe, was studied in a newly invaded area in Italy. The hypothesis being tested was that the reproductive success of the insect depend on habitat type and tree suitability. Adult beetles were caged on branches of host and nonhost species, in both urban and forest habitats. Two months later, number and size of feeding patches on plant tissues, eggs laid, and surviving larvae were assessed. Bark concentration of C and N was also measured from the same trees. Results indicated that the mean area of plant tissues consumed by adult feeding was significantly larger on trees growing in forest than in urban habitat, although within the same habitat there were no differences between susceptible and nonsusceptible trees. ALB tree colonization, in terms of number of eggs laid and young larvae survival, was not affected by habitat while it was higher on susceptible trees. Although trees growing in forests had a lower nitrogen concentration, they allowed colonization rates similar to those of trees growing in the urban habitat. Hence, the amount of carbon and nitrogen did not fully explain tree suitability or habitat selection. We suggest compensatory feeding as a potential mechanism that might explain this peculiar situation, as supported by a more intensive feeding activity recorded on trees in the forest. Suitability of different trees may be due to other factors, such as secondary chemical compounds. PMID:25424840

  6. Predicting spatial and temporal distribution of Indo-Pacific lionfish (Pterois volitans) in Biscayne Bay through habitat suitability modeling

    USGS Publications Warehouse

    Bernal, Nicholas A.; DeAngelis, Donald L.; Schofield, Pamela J.; Sullivan Sealey, Kathleen

    2014-01-01

    Invasive species may exhibit higher levels of growth and reproduction when environmental conditions are most suitable, and thus their effects on native fauna may be intensified. Understanding potential impacts of these species, especially in the nascent stages of a biological invasion, requires critical information concerning spatial and temporal distributions of habitat suitability. Using empirically supported environmental variables (e.g., temperature, salinity, dissolved oxygen, rugosity, and benthic substrate), our models predicted habitat suitability for the invasive lionfish (Pterois volitans) in Biscayne Bay, Florida. The use of Geographic Information Systems (GIS) as a platform for the modeling process allowed us to quantify correlations between temporal (seasonal) fluctuations in the above variables and the spatial distribution of five discrete habitat quality classes, whose ranges are supported by statistical deviations from the apparent best conditions described in prior studies. Analysis of the resulting models revealed little fluctuation in spatial extent of the five habitat classes on a monthly basis. Class 5, which represented the area with environmental variables closest to the best conditions for lionfish, occupied approximately one-third of Biscayne Bay, with subsequent habitats declining in area. A key finding from this study was that habitat suitability increased eastward from the coastline, where higher quality habitats were adjacent to the Atlantic Ocean and displayed marine levels of ambient water quality. Corroboration of the models with sightings from the USGS-NAS database appeared to support our findings by nesting 79 % of values within habitat class 5; however, field testing (i.e., lionfish surveys) is necessary to confirm the relationship between habitat classes and lionfish distribution.

  7. Habitat suitability of the Atlantic bluefin tuna by size class: An ecological niche approach

    NASA Astrophysics Data System (ADS)

    Druon, Jean-Noël; Fromentin, Jean-Marc; Hanke, Alex R.; Arrizabalaga, Haritz; Damalas, Dimitrios; Tičina, Vjekoslav; Quílez-Badia, Gemma; Ramirez, Karina; Arregui, Igor; Tserpes, George; Reglero, Patricia; Deflorio, Michele; Oray, Isik; Saadet Karakulak, F.; Megalofonou, Persefoni; Ceyhan, Tevfik; Grubišić, Leon; MacKenzie, Brian R.; Lamkin, John; Afonso, Pedro; Addis, Piero

    2016-03-01

    An ecological niche modelling (ENM) approach was used to predict the potential feeding and spawning habitats of small (5-25 kg, only feeding) and large (>25 kg) Atlantic bluefin tuna (ABFT), Thunnus thynnus, in the Mediterranean Sea, the North Atlantic and the Gulf of Mexico. The ENM was built bridging knowledge on ecological traits of ABFT (e.g. temperature tolerance, mobility, feeding and spawning strategy) with patterns of selected environmental variables (chlorophyll-a fronts and concentration, sea surface current and temperature, sea surface height anomaly) that were identified using an extensive set of precisely geo-located presence data. The results highlight a wider temperature tolerance for larger fish allowing them to feed in the northern - high chlorophyll levels - latitudes up to the Norwegian Sea in the eastern Atlantic and to the Gulf of Saint Lawrence in the western basin. Permanent suitable feeding habitat for small ABFT was predicted to be mostly located in temperate latitudes in the North Atlantic and in the Mediterranean Sea, as well as in subtropical waters off north-west Africa, while summer potential habitat in the Gulf of Mexico was found to be unsuitable for both small and large ABFTs. Potential spawning grounds were found to occur in the Gulf of Mexico from March-April in the south-east to April-May in the north, while favourable conditions evolve in the Mediterranean Sea from mid-May in the eastern to mid-July in the western basin. Other secondary potential spawning grounds not supported by observations were predicted in the Azores area and off Morocco to Senegal during July and August when extrapolating the model settings from the Gulf of Mexico into the North Atlantic. The presence of large ABFT off Florida and the Bahamas in spring was not explained by the model as is, however the environmental variables other than the sea surface height anomaly appeared to be favourable for spawning in part of this area. Defining key spatial and

  8. An Iterative and Targeted Sampling Design Informed by Habitat Suitability Models for Detecting Focal Plant Species over Extensive Areas

    PubMed Central

    Wang, Ophelia; Zachmann, Luke J.; Sesnie, Steven E.; Olsson, Aaryn D.; Dickson, Brett G.

    2014-01-01

    Prioritizing areas for management of non-native invasive plants is critical, as invasive plants can negatively impact plant community structure. Extensive and multi-jurisdictional inventories are essential to prioritize actions aimed at mitigating the impact of invasions and changes in disturbance regimes. However, previous work devoted little effort to devising sampling methods sufficient to assess the scope of multi-jurisdictional invasion over extensive areas. Here we describe a large-scale sampling design that used species occurrence data, habitat suitability models, and iterative and targeted sampling efforts to sample five species and satisfy two key management objectives: 1) detecting non-native invasive plants across previously unsampled gradients, and 2) characterizing the distribution of non-native invasive plants at landscape to regional scales. Habitat suitability models of five species were based on occurrence records and predictor variables derived from topography, precipitation, and remotely sensed data. We stratified and established field sampling locations according to predicted habitat suitability and phenological, substrate, and logistical constraints. Across previously unvisited areas, we detected at least one of our focal species on 77% of plots. In turn, we used detections from 2011 to improve habitat suitability models and sampling efforts in 2012, as well as additional spatial constraints to increase detections. These modifications resulted in a 96% detection rate at plots. The range of habitat suitability values that identified highly and less suitable habitats and their environmental conditions corresponded to field detections with mixed levels of agreement. Our study demonstrated that an iterative and targeted sampling framework can address sampling bias, reduce time costs, and increase detections. Other studies can extend the sampling framework to develop methods in other ecosystems to provide detection data. The sampling methods

  9. The Areal Extent of Brown Shrimp Habitat Suitability in Mobile Bay, Alabama USA: Targeting Vegetated Habitat Restoration

    EPA Science Inventory

    The availability of wetlands and shallow water habitats significantly influences Gulf of Mexico (GOM) penaeid shrimp fishery productivity. However, the GOM region has the highest rate of wetland loss in the U.S. Protection and management of these vital GOM habitats are critical t...

  10. A Resource-Based Modelling Framework to Assess Habitat Suitability for Steppe Birds in Semiarid Mediterranean Agricultural Systems

    PubMed Central

    Cardador, Laura; De Cáceres, Miquel; Bota, Gerard; Giralt, David; Casas, Fabián; Arroyo, Beatriz; Mougeot, François; Cantero-Martínez, Carlos; Moncunill, Judit; Butler, Simon J.; Brotons, Lluís

    2014-01-01

    European agriculture is undergoing widespread changes that are likely to have profound impacts on farmland biodiversity. The development of tools that allow an assessment of the potential biodiversity effects of different land-use alternatives before changes occur is fundamental to guiding management decisions. In this study, we develop a resource-based model framework to estimate habitat suitability for target species, according to simple information on species’ key resource requirements (diet, foraging habitat and nesting site), and examine whether it can be used to link land-use and local species’ distribution. We take as a study case four steppe bird species in a lowland area of the north-eastern Iberian Peninsula. We also compare the performance of our resource-based approach to that obtained through habitat-based models relating species’ occurrence and land-cover variables. Further, we use our resource-based approach to predict the effects that change in farming systems can have on farmland bird habitat suitability and compare these predictions with those obtained using the habitat-based models. Habitat suitability estimates generated by our resource-based models performed similarly (and better for one study species) than habitat based-models when predicting current species distribution. Moderate prediction success was achieved for three out of four species considered by resource-based models and for two of four by habitat-based models. Although, there is potential for improving the performance of resource-based models, they provide a structure for using available knowledge of the functional links between agricultural practices, provision of key resources and the response of organisms to predict potential effects of changing land-uses in a variety of context or the impacts of changes such as altered management practices that are not easily incorporated into habitat-based models. PMID:24667825

  11. Spatially explicit feedbacks between seagrass meadow structure, sediment and light: Habitat suitability for seagrass growth

    USGS Publications Warehouse

    Carr, Joel; D'Odorico, Paul; McGlathery, Karen; Wiberg, Patricia L.

    2016-01-01

    In shallow coastal bays where nutrient loading and riverine inputs are low, turbidity, and the consequent light environment are controlled by resuspension of bed sediments due to wind-waves and tidal currents. High sediment resuspension and low light environments can limit benthic primary productivity; however, both currents and waves are affected by the presence of benthic plants such as seagrass. This feedback between the presence of benthic primary producers such as seagrass and the consequent light environment has been predicted to induce bistable dynamics locally. However, these vegetated areas influence a larger area than they footprint, including a barren adjacent downstream area which exhibits reduced shear stresses. Here we explore through modeling how the patchy structure of seagrass meadows on a landscape may affect sediment resuspension and the consequent light environment due to the presence of this sheltered region. Heterogeneous vegetation covers comprising a mosaic of randomly distributed patches were generated to investigate the effect of patch modified hydrodynamics. Actual cover of vegetation on the landscape was used to facilitate comparisons across landscape realizations. Hourly wave and current shear stresses on the landscape along with suspended sediment concentration and light attenuation characteristics were then calculated and spatially averaged to examine how actual cover and mean water depth affect the bulk sediment and light environment. The results indicate that an effective cover, which incorporates the sheltering area, has important controls on the distributions of shear stress, suspended sediment, light environment, and consequent seagrass habitat suitability. Interestingly, an optimal habitat occurs within a depth range where, if actual cover is reduced past some threshold, the bulk light environment would no longer favor seagrass growth.

  12. Impact of Alternative Environmental Flow Prescriptions on Hydropower Production and Fish Habitat Suitability

    NASA Astrophysics Data System (ADS)

    Castellarin, A.; Ceola, S.; Pugliese, A.; Galeati, G. A.

    2015-12-01

    Anthropogenic activities along streams and rivers are increasingly recognized to be a major concern for fluvial ecosystems. The management of water resources, by means of e.g. flow diversions and dams, for industrial, agricultural, water-supply, hydropower production and flood protection purposes induces significant changes to the natural streamflow regime of a river. Indeed, the river flow regime is known to be a major abiotic factor influencing fluvial ecosystems. An established approach aimed at preserving the behaviour and distribution of fluvial species relies on the definition of minimum streamflow requirements (i.e., environmental flows) downstream of dams and diversion structures. Such environmental flows are normally identified through methodologies that have an empirical nature and may not be representative of local ecological and hydraulic conditions. While the effect of imposing a minimum discharge release is easily predictable in terms of e.g. loss of hydropower production, the advantages in terms of species preferences are often poorly understood and seldom assessed. To analyze the interactions between flow releases and the behaviour and distribution of fluvial species (i.e., from periphyton, to benthic invertebrate and fish), one may use a habitat suitability curve, which is a fundamental tool capable of describing species preferences influenced by any generic environmental variable. The outcomes of a real case study applied to several Italian rivers, located in the Marche administrative district in Central Italy (∽10000km2), in which we quantitatively assess the effects of alternative environmental flow scenarios on the existing hydropower network and on two fish species that are quite abundant in the study area (i.e., Leuciscus cephalus cabeda and Barbus barbus plebejus), will be presented and discussed. The proposed analysis, which can be easily adapted to different riparian habitats and hydrological contexts, is a useful tool to guide the

  13. Application of NASA Observational Data and Habitat Suitability Modeling to Wavyleaf Basketgrass (Oplismenus hirtellus)

    NASA Astrophysics Data System (ADS)

    Hawkins, C.; Suss, C.

    2011-12-01

    In 1997, a rapidly spreading invasive grass known as Wavyleaf Basketgrass (Oplismenus hirtellus, WLBG), was found in Maryland's Patapsco Valley State Park. It is a low-lying, trailing perennial grass, branching and rooting at the lower stem nodes. The leaves are short and hairy, and produce a sticky substance that can adhere to passing animals and further its dispersion. WLBG is similar to Japanese stiltgrass, which has taken over Eastern forests in the last 25 years. WLBG, a stoloniferous grass, covers the forest floor, crowds out native herbaceous plants, and negatively alters the habitats of plants and animals in that ecosystem. It has spread beyond the park into the surrounding areas and other parts of Maryland and Virginia. How it arrived to Maryland is still unknown but mitigation efforts are clearly required and are being undertaken by the Maryland Department of Natural Resources (MD DNR) Wildlife and Heritage Service (WHS). The maximum entropy (MaxEnt) method was used to model the potential distribution of WLBG in the Maryland region. MaxEnt models species distributions from presence-only records, making it particularly well-suited for the types of data collected by resource managers such as the WHS. Input into the MaxEnt model were a combination of in situ presence points and covariates (environmental predictors) comprised of environmental data and NASA Earth observation data that are ecologically relevant to WLBG. These environmental predictors include temperature and precipitation data, soil classifications, landcover measures and classifications, and topology data including elevation, aspect, and slope. The remotely sensed data layers include products derived from Landsat 5 and 7, Moderate Resolution Imaging Spectroradiometer (MODIS), and the Shuttle Radar Topography Mission (SRTM). MaxEnt produced a list of top covariate contributors and created habitat suitability maps to predict potential areas where WLBG may spread.

  14. Spatially explicit feedbacks between seagrass meadow structure, sediment and light: Habitat suitability for seagrass growth

    NASA Astrophysics Data System (ADS)

    Carr, Joel A.; D'Odorico, Paolo; McGlathery, Karen J.; Wiberg, Patricia L.

    2016-07-01

    In shallow coastal bays where nutrient loading and riverine inputs are low, turbidity, and the consequent light environment are controlled by resuspension of bed sediments due to wind-waves and tidal currents. High sediment resuspension and low light environments can limit benthic primary productivity; however, both currents and waves are affected by the presence of benthic plants such as seagrass. This feedback between the presence of benthic primary producers such as seagrass and the consequent light environment has been predicted to induce bistable dynamics locally. However, these vegetated areas influence a larger area than they footprint, including a barren adjacent downstream area which exhibits reduced shear stresses. Here we explore through modeling how the patchy structure of seagrass meadows on a landscape may affect sediment resuspension and the consequent light environment due to the presence of this sheltered region. Heterogeneous vegetation covers comprising a mosaic of randomly distributed patches were generated to investigate the effect of patch modified hydrodynamics. Actual cover of vegetation on the landscape was used to facilitate comparisons across landscape realizations. Hourly wave and current shear stresses on the landscape along with suspended sediment concentration and light attenuation characteristics were then calculated and spatially averaged to examine how actual cover and mean water depth affect the bulk sediment and light environment. The results indicate that an effective cover, which incorporates the sheltering area, has important controls on the distributions of shear stress, suspended sediment, light environment, and consequent seagrass habitat suitability. Interestingly, an optimal habitat occurs within a depth range where, if actual cover is reduced past some threshold, the bulk light environment would no longer favor seagrass growth.

  15. Impact of alternative environmental flow prescriptions on hydropower production and fish habitat suitability

    NASA Astrophysics Data System (ADS)

    Ceola, Serena; Pugliese, Alessio; Castellarin, Attilio; Galeati, Giorgio

    2015-04-01

    Anthropogenic activities along streams and rivers are increasingly recognised to be a major concern for fluvial ecosystems. The management of water resources, by means of e.g. flow diversions and dams, for industrial, agricultural, water-supply, hydropower production and flood protection purposes induces significant changes to the natural streamflow regime of a river. Indeed, the river flow regime is known to be a major abiotic factor influencing fluvial ecosystems. An established approach aimed at preserving the behaviour and distribution of fluvial species relies on the definition of minimum streamflow requirements (i.e., environmental flows) downstream of dams and diversion structures. Such environmental flows are normally identified through methodologies that have an empirical nature and may not be representative of local ecological and hydraulic conditions. While the effect of imposing a minimum discharge release is easily predictable in terms of e.g. loss of hydropower production, the advantages in terms of species preferences are often poorly understood and seldom assessed. To analyse the interactions between flow releases and the behaviour and distribution of fluvial species (i.e., from periphyton, to benthic invertebrate and fish), one may use a habitat suitability curve, which is a fundamental tool capable of describing species preferences influenced by any generic environmental variable. The outcomes of a real case study applied to several Italian rivers, located in the Marche administrative district in Central Italy (∽10000km2), in which we quantitatively assess the effects of alternative environmental flow scenarios on the existing hydropower network and on two fish species that are quite abundant in the study area (i.e., Leuciscus cephalus cabeda and Barbus barbus plebejus), will be presented and discussed. The proposed analysis, which can be easily adapted to different riparian habitats and hydrological contexts, is a useful tool to guide the

  16. Climate Change, Northern Birds of Conservation Concern and Matching the Hotspots of Habitat Suitability with the Reserve Network

    PubMed Central

    Virkkala, Raimo; Heikkinen, Risto K.; Fronzek, Stefan; Leikola, Niko

    2013-01-01

    National reserve networks are one of the most important means of species conservation, but their efficiency may be diminished due to the projected climatic changes. Using bioclimatic envelope models and spatial data on habitats and conservation areas, we studied how efficient the reserve network will be in preserving 100 forest, mire, marshland, and alpine bird species of conservation concern in Finland in 2051–2080 under three different climate scenarios. The occurrences of the studied bird species were related to the amount of habitat preferred by each species in the different boreal zones. We employed a novel integrated habitat suitability index that takes into account both the species’ probability of occurrence from the bioclimatic models and the availability of suitable habitat. Using this suitability index, the distribution of the topmost 5% suitability squares (“hotspots”) in the four bird species groups in the period 1971–2000 and under the three scenarios were compared with the location of reserves with the highest amounts of the four habitats to study the efficiency of the network. In species of mires, marshlands, and Arctic mountains, a high proportion of protected habitat was included in the 5% hotspots in the scenarios in 2051–2080, showing that protected areas cover a high proportion of occurrences of bird species. In contrast, in forests in the southern and middle boreal zones, only a small proportion of the protected habitat was included in the 5% hotspots, indicating that the efficiency of the protected area network will be insufficient for forest birds in the future. In the northern boreal zone, the efficiency of the reserve network in forests was highly dependent on the strength of climate change varying between the scenarios. Overall, there is no single solution to preserving biodiversity in a changing climate, but several future pathways should be considered. PMID:23700420

  17. Predicting suitable habitat for the gold coral Savalia savaglia (Bertoloni, 1819) (Cnidaria, Zoantharia) in the South Tyrrhenian Sea

    NASA Astrophysics Data System (ADS)

    Giusti, Michela; Innocenti, Carlo; Canese, Simonepietro

    2014-06-01

    The gold coral Savalia savaglia (Cnidaria, Zoantharia) is a rare component of the mesophotic zone of the Mediterranean Sea and northeastern Atlantic Ocean. During two field campaigns along the Italian coast in the South Tyrrhenian Sea, two populations of this species were discovered. The specimens were filmed and photographed by means of a Remotely Operated Vehicle (ROV). To identify the role of local bathymetry and other derived variables on presence and distribution of S. savaglia we used a Habitat Suitability (HS) modeling technique based on Ecological Niche Factor Analysis (ENFA), utilizing high-resolution multibeam bathymetry and ROV data. Among the set of environmental variables derived from multibeam data, slope, rugosity, eastness and distance to rocks, appear to be the main variables involved in S. savaglia distribution, pointing out that the habitat differs considerably from the mean environmental conditions over the study area, and that S. savaglia ecological niche is significantly narrower than the available habitat. The HS map was developed to differentiate the sea floor into suitability classes. The comparison between suitability classes and presence data showed that the HS map is coherent with the observed spatial distribution of the species. The most suitable habitat for S. savaglia is characterized by a rough sea floor with rocks that is steeply sloped, oriented northeast, and within a water depth range of 34-77 m. Our study suggests that predictive modeling is an approach that can be applied to other deep coral species to locate areas with a suitable habitat. Considering the difficulties to reach the habitats in which these species live, this approach could be essential to planning further studies that help define areas where the species may be present.

  18. Predictive mechanistic bioenergetics to model habitat suitability of shellfish culture in coastal lakes

    NASA Astrophysics Data System (ADS)

    Rinaldi, A.; Montalto, V.; Manganaro, A.; Mazzola, A.; Mirto, S.; Sanfilippo, M.; Sarà, G.

    2014-05-01

    Quantitative tools based on mechanistic modelling of functional traits able to enhance the sustainability of aquaculture and most other human activities (i.e. reducing the likelihood of detrimental impacts optimising productions), are especially important factors in the decision to site aquaculture facilities in coastal lakes, ponds and lagoons and, in the case of detrimental impact, to adopt mitigation measures. We tested the ability of mechanistic functional trait based models to predict life history traits of cultivable shellfish in shallow coastal lakes. Dynamic Energy Budget (DEB) models were run to generate spatially explicit predictions of Mytilus galloprovincialis life history (LH) traits (e.g. body size and fecundity). Using fortnightly data of food supply and hourly data of body temperatures, and exploiting the power of mechanistic rules, we estimated the amount of faeces ejected by a fixed quantity of organisms cultivated in two shallow Southern Mediterranean (Sicily) lakes. These differed in terms of temperature and food density, implying large differences in life history traits of mussels in the two study areas. This information could help facilitate the selection of sites where environmental conditions are more suitable for aquaculture and contextually compatible with sustainability. The validation exercise obtained by comparing the predicted and observed data was nearly consistent. Therefore, a mechanistic functional traits-based model seems able to capture the link between habitat characteristics and functional traits of organisms, delineating the fundamental portion of an ecological niche, the possibility of predicting LH traits and potential ecological applications in the management of natural coastal resources.

  19. Characterizing the thermal suitability of instream habitat for salmonids: A cautionary example from the Rocky Mountains

    USGS Publications Warehouse

    Al-Chokhachy, Robert K.; Wegner, Seth J.; Isaak, Daniel J.; Kershner, Jeffrey L.

    2013-01-01

    Understanding a species’ thermal niche is becoming increasingly important for management and conservation within the context of global climate change, yet there have been surprisingly few efforts to compare assessments of a species’ thermal niche across methods. To address this uncertainty, we evaluated the differences in model performance and interpretations of a species’ thermal niche when using different measures of stream temperature and surrogates for stream temperature. Specifically, we used a logistic regression modeling framework with three different indicators of stream thermal conditions (elevation, air temperature, and stream temperature) referenced to a common set of Brook Trout Salvelinus fontinalis distribution data from the Boise River basin, Idaho. We hypothesized that stream temperature predictions that were contemporaneous with fish distribution data would have stronger predictive performance than composite measures of stream temperature or any surrogates for stream temperature. Across the different indicators of thermal conditions, the highest measure of accuracy was found for the model based on stream temperature predictions that were contemporaneous with fish distribution data (percent correctly classified = 71%). We found considerable differences in inferences across models, with up to 43% disagreement in the amount of stream habitat that was predicted to be suitable. The differences in performance between models support the growing efforts in many areas to develop accurate stream temperature models for investigations of species’ thermal niches.

  20. Modeling habitat suitability of the invasive clam Corbicula fluminea in a Neotropical shallow lagoon, southern Brazil.

    PubMed

    Silveira, T C L; Gama, A M S; Alves, T P; Fontoura, N F

    2016-04-19

    This study aimed to model the habitat suitability for an invasive clam Corbicula fluminea in a coastal shallow lagoon in the southern Neotropical region (-30.22, -50.55). The lagoon (19km2, maximum deep 2.5m) was sampled with an Ekman dredge in an orthogonal matrix comprising 84 points. At each sampling point, were obtained environmental descriptors as depth, organic matter content (OMC), average granulometry (Avgran), and the percentage of sand (Pcsand). Prediction performance of Generalized Linear Models (GLM), Generalized Additive Models (GAM) and Boosted Regression Tree (BRT) were compared. Also, niche overlapping with other native clam species (Castalia martensi, Neocorbicula limosa and Anodontites trapesialis) was examined. A BRT model with 1400 trees was selected as the best model, with cross-validated correlation of 0.82. The relative contributions of predictors were Pcsand-42.6%, OMC-35.8%, Avgran-10.9% and Depth-10.8%. Were identified that C. fluminea occur mainly in sandy sediments with few organic matter, in shallow areas nor by the shore. The PCA showed a wide niche overlap with the native clam species C. martensi, N. limosa and A. trapesialis. PMID:27097092

  1. Anticipating Knowledge to Inform Species Management: Predicting Spatially Explicit Habitat Suitability of a Colonial Vulture Spreading Its Range

    PubMed Central

    Mateo-Tomás, Patricia; Olea, Pedro P.

    2010-01-01

    Background The knowledge of both potential distribution and habitat suitability is fundamental in spreading species to inform in advance management and conservation planning. After a severe decline in the past decades, the griffon vulture (Gyps fulvus) is now spreading its breeding range towards the northwest in Spain and Europe. Because of its key ecological function, anticipated spatial knowledge is required to inform appropriately both vulture and ecosystem management. Methodology/Findings Here we used maximum entropy (Maxent) models to determine the habitat suitability of potential and current breeding distribution of the griffon vulture using presence-only data (N = 124 colonies) in north-western Spain. The most relevant ecological factors shaping this habitat suitability were also identified. The resulting model had a high predictive performance and was able to predict species' historical distribution. 7.5% (∼1,850 km2) of the study area resulted to be suitable breeding habitat, most of which (∼70%) is already occupied by the species. Cliff availability and livestock density, especially of sheep and goats, around 10 km of the colonies were the fundamental factors determining breeding habitat suitability for this species. Conclusions/Significance Griffon vultures could still spread 50–60 km towards the west, increasing their breeding range in 1,782 km2. According to our results, 7.22% of the area suitable for griffon vulture will be affected by wind farms, so our results could help to better plan wind farm locations. The approach here developed could be useful to inform management of reintroductions and recovery programmes currently being implemented for both the griffon vulture and other threatened vulture species. PMID:20811501

  2. Present and Future Projections of Habitat Suitability of the Asian Tiger Mosquito, a Vector of Viral Pathogens, from Global Climate Simulations.

    NASA Astrophysics Data System (ADS)

    Proestos, Y.; Christophides, G.; Erguler, K.; Tanarhte, M.; Waldock, J.; Lelieveld, J.

    2014-12-01

    Climate change can influence the transmission of vector borne diseases (VBDs) through altering the habitat suitability of insect vectors. Here we present global climate model simulations and evaluate the associated uncertainties in view of the main meteorological factors that may affect the distribution of the Asian Tiger mosquito (Aedes albopictus), which can transmit pathogens that cause Chikungunya, Dengue fever, yellow fever and various encephalitides. Using a general circulation model (GCM) at 50 km horizontal resolution to simulate mosquito survival variables including temperature, precipitation and relative humidity, we present both global and regional projections of the habitat suitability up to the middle of the 21st century. The model resolution of 50 km allows evaluation against previous projections for Europe and provides a basis for comparative analyses with other regions. Model uncertainties and performance are addressed in light of the recent CMIP5 ensemble climate model simulations for the RCP8.5 concentration pathway and using meteorological re-analysis data (ERA-Interim/ECMWF) for the recent past. Uncertainty ranges associated with the thresholds of meteorological variables that may affect the distribution of Ae. albopictus are diagnosed using fuzzy-logic methodology, notably to assess the influence of selected meteorological criteria and combinations of criteria that influence mosquito habitat suitability. From the climate projections for 2050, and adopting a habitat suitability index larger than 70%, we estimate that about 2.4 billion individuals in a land area of nearly 20 million square kilometres will potentially be exposed to Ae. albopictus. The synthesis of fuzzy-logic based on mosquito biology and climate change analysis provides new insights into the regional and global spreading of VBDs to support disease control and policy making.

  3. Present and future projections of habitat suitability of the Asian tiger mosquito, a vector of viral pathogens, from global climate simulation.

    PubMed

    Proestos, Y; Christophides, G K; Ergüler, K; Tanarhte, M; Waldock, J; Lelieveld, J

    2015-04-01

    Climate change can influence the transmission of vector-borne diseases (VBDs) through altering the habitat suitability of insect vectors. Here we present global climate model simulations and evaluate the associated uncertainties in view of the main meteorological factors that may affect the distribution of the Asian tiger mosquito (Aedes albopictus), which can transmit pathogens that cause chikungunya, dengue fever, yellow fever and various encephalitides. Using a general circulation model at 50 km horizontal resolution to simulate mosquito survival variables including temperature, precipitation and relative humidity, we present both global and regional projections of the habitat suitability up to the middle of the twenty-first century. The model resolution of 50 km allows evaluation against previous projections for Europe and provides a basis for comparative analyses with other regions. Model uncertainties and performance are addressed in light of the recent CMIP5 ensemble climate model simulations for the RCP8.5 concentration pathway and using meteorological re-analysis data (ERA-Interim/ECMWF) for the recent past. Uncertainty ranges associated with the thresholds of meteorological variables that may affect the distribution of Ae. albopictus are diagnosed using fuzzy-logic methodology, notably to assess the influence of selected meteorological criteria and combinations of criteria that influence mosquito habitat suitability. From the climate projections for 2050, and adopting a habitat suitability index larger than 70%, we estimate that approximately 2.4 billion individuals in a land area of nearly 20 million km(2) will potentially be exposed to Ae. albopictus. The synthesis of fuzzy-logic based on mosquito biology and climate change analysis provides new insights into the regional and global spreading of VBDs to support disease control and policy making. PMID:25688015

  4. Present and future projections of habitat suitability of the Asian tiger mosquito, a vector of viral pathogens, from global climate simulation

    PubMed Central

    Proestos, Y.; Christophides, G. K.; Ergüler, K.; Tanarhte, M.; Waldock, J.; Lelieveld, J.

    2015-01-01

    Climate change can influence the transmission of vector-borne diseases (VBDs) through altering the habitat suitability of insect vectors. Here we present global climate model simulations and evaluate the associated uncertainties in view of the main meteorological factors that may affect the distribution of the Asian tiger mosquito (Aedes albopictus), which can transmit pathogens that cause chikungunya, dengue fever, yellow fever and various encephalitides. Using a general circulation model at 50 km horizontal resolution to simulate mosquito survival variables including temperature, precipitation and relative humidity, we present both global and regional projections of the habitat suitability up to the middle of the twenty-first century. The model resolution of 50 km allows evaluation against previous projections for Europe and provides a basis for comparative analyses with other regions. Model uncertainties and performance are addressed in light of the recent CMIP5 ensemble climate model simulations for the RCP8.5 concentration pathway and using meteorological re-analysis data (ERA-Interim/ECMWF) for the recent past. Uncertainty ranges associated with the thresholds of meteorological variables that may affect the distribution of Ae. albopictus are diagnosed using fuzzy-logic methodology, notably to assess the influence of selected meteorological criteria and combinations of criteria that influence mosquito habitat suitability. From the climate projections for 2050, and adopting a habitat suitability index larger than 70%, we estimate that approximately 2.4 billion individuals in a land area of nearly 20 million km2 will potentially be exposed to Ae. albopictus. The synthesis of fuzzy-logic based on mosquito biology and climate change analysis provides new insights into the regional and global spreading of VBDs to support disease control and policy making. PMID:25688015

  5. Modelling suitable estuarine habitats for Zostera noltii , using Ecological Niche Factor Analysis and Bathymetric LiDAR

    NASA Astrophysics Data System (ADS)

    Valle, Mireia; Borja, Ángel; Chust, Guillem; Galparsoro, Ibon; Garmendia, Joxe Mikel

    2011-08-01

    Predicting species distribution and habitat suitability is of considerable use in supporting the implementation of environmental legislation, protection and conservation of marine waters and ecosystem-based management. As other seagrasses, Zostera noltii has declined worldwide, mainly due to human pressures, such as eutrophication and habitat loss. In the case of the Basque Country (northern Spain), the species is present only in 3 out of 12 estuaries. From the literature, it is known that at least 6 of these estuaries were formerly vegetated by this seagrass. Consequently, efforts to monitor and restore (potential) habitats have been enhanced. Therefore, we aim: (i) to determine the main environmental variables explaining Zostera noltii distribution, within the Basque estuaries based upon the Oka estuary; (ii) to model habitat suitability for this species, as a wider applicable management-decision tool for seagrass restoration; and (iii) to assess the applicability and predicted accuracy of the model by using internal and external validation methods. For this purpose, Ecological Niche Factor Analysis (ENFA) has been used to model habitat suitability, based upon topographical variables, obtained from bathymetric Light Detection And Ranging (LiDAR); sediment characteristics variables; and hydrodynamic variables. The results obtained from the ecological factors of the ENFA (Marginality: 1.00; Specialization: 2.59) indicate that the species habitat differs considerably from the mean environmental conditions over the study area; likewise, that the species is restrictive in the selection of the range of conditions within which it dwells. The main environmental variables relating to the species distribution, in order of importance, are: mean grain size; redox potential; intertidal height; sediment sorting; slope of intertidal flat; percentage of gravels; and percentage of organic matter content. The model has a high predicted accuracy (Boyce index: 0.92). Model

  6. Environmental variables and definitive host distribution: a habitat suitability modelling for endohelminth parasites in the marine realm

    PubMed Central

    Kuhn, Thomas; Cunze, Sarah; Kochmann, Judith; Klimpel, Sven

    2016-01-01

    Marine nematodes of the genus Anisakis are common parasites of a wide range of aquatic organisms. Public interest is primarily based on their importance as zoonotic agents of the human Anisakiasis, a severe infection of the gastro-intestinal tract as result of consuming live larvae in insufficiently cooked fish dishes. The diverse nature of external impacts unequally influencing larval and adult stages of marine endohelminth parasites requires the consideration of both abiotic and biotic factors. Whereas abiotic factors are generally more relevant for early life stages and might also be linked to intermediate hosts, definitive hosts are indispensable for a parasite’s reproduction. In order to better understand the uneven occurrence of parasites in fish species, we here use the maximum entropy approach (Maxent) to model the habitat suitability for nine Anisakis species accounting for abiotic parameters as well as biotic data (definitive hosts). The modelled habitat suitability reflects the observed distribution quite well for all Anisakis species, however, in some cases, habitat suitability exceeded the known geographical distribution, suggesting a wider distribution than presently recorded. We suggest that integrative modelling combining abiotic and biotic parameters is a valid approach for habitat suitability assessments of Anisakis, and potentially other marine parasite species. PMID:27507328

  7. Environmental variables and definitive host distribution: a habitat suitability modelling for endohelminth parasites in the marine realm.

    PubMed

    Kuhn, Thomas; Cunze, Sarah; Kochmann, Judith; Klimpel, Sven

    2016-01-01

    Marine nematodes of the genus Anisakis are common parasites of a wide range of aquatic organisms. Public interest is primarily based on their importance as zoonotic agents of the human Anisakiasis, a severe infection of the gastro-intestinal tract as result of consuming live larvae in insufficiently cooked fish dishes. The diverse nature of external impacts unequally influencing larval and adult stages of marine endohelminth parasites requires the consideration of both abiotic and biotic factors. Whereas abiotic factors are generally more relevant for early life stages and might also be linked to intermediate hosts, definitive hosts are indispensable for a parasite's reproduction. In order to better understand the uneven occurrence of parasites in fish species, we here use the maximum entropy approach (Maxent) to model the habitat suitability for nine Anisakis species accounting for abiotic parameters as well as biotic data (definitive hosts). The modelled habitat suitability reflects the observed distribution quite well for all Anisakis species, however, in some cases, habitat suitability exceeded the known geographical distribution, suggesting a wider distribution than presently recorded. We suggest that integrative modelling combining abiotic and biotic parameters is a valid approach for habitat suitability assessments of Anisakis, and potentially other marine parasite species. PMID:27507328

  8. Development and validation of a habitat suitability model for the non-indigenous seagrass Zostera japonica in North America

    EPA Science Inventory

    We developed a spatially-explicit, flexible 3-parameter habitat suitability model that can be used to identify and predict areas at higher risk for non-native dwarf eelgrass (Zostera japonica) invasion. The model uses simple environmental parameters (depth, nearshore slope, and s...

  9. Numerical analysis of effects of large wood structures on channel morphology and fish habitat suitability in Little Topashaw Creek

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A depth-averaged two dimensional (2D) model has been applied to simulate the effect of large wood structures (LWS) on flow, sediment transport, bed change, and fish habitat suitability in a deeply-incised sharp bend in the Little Topashaw Creek, North Central Mississippi. The hydrodynamic simulation...

  10. Modeling "habitat suitability" for a herbicide resistant weed using a species distribution model and presence-only data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Herbicide resistant weeds are like invasive weeds: prompt management is needed to prevent their spread. For invasive weeds, first reports of a weed's occurrence are often analyzed with species distribution models (SDM) to prioritize detection and treatment. Suitability of other areas as habitat for ...

  11. Environmental variables and definitive host distribution: a habitat suitability modelling for endohelminth parasites in the marine realm

    NASA Astrophysics Data System (ADS)

    Kuhn, Thomas; Cunze, Sarah; Kochmann, Judith; Klimpel, Sven

    2016-08-01

    Marine nematodes of the genus Anisakis are common parasites of a wide range of aquatic organisms. Public interest is primarily based on their importance as zoonotic agents of the human Anisakiasis, a severe infection of the gastro-intestinal tract as result of consuming live larvae in insufficiently cooked fish dishes. The diverse nature of external impacts unequally influencing larval and adult stages of marine endohelminth parasites requires the consideration of both abiotic and biotic factors. Whereas abiotic factors are generally more relevant for early life stages and might also be linked to intermediate hosts, definitive hosts are indispensable for a parasite’s reproduction. In order to better understand the uneven occurrence of parasites in fish species, we here use the maximum entropy approach (Maxent) to model the habitat suitability for nine Anisakis species accounting for abiotic parameters as well as biotic data (definitive hosts). The modelled habitat suitability reflects the observed distribution quite well for all Anisakis species, however, in some cases, habitat suitability exceeded the known geographical distribution, suggesting a wider distribution than presently recorded. We suggest that integrative modelling combining abiotic and biotic parameters is a valid approach for habitat suitability assessments of Anisakis, and potentially other marine parasite species.

  12. A Presence-Only Model of Suitable Roosting Habitat for the Endangered Indiana Bat in the Southern Appalachians.

    PubMed

    Hammond, Kristina R; O'Keefe, Joy M; Aldrich, Stephen P; Loeb, Susan C

    2016-01-01

    We know little about how forest bats, which are cryptic and mobile, use roosts on a landscape scale. For widely distributed species like the endangered Indiana bat Myotis sodalis, identifying landscape-scale roost habitat associations will be important for managing the species in different regions where it occurs. For example, in the southern Appalachian Mountains, USA, M. sodalis roosts are scattered across a heavily forested landscape, which makes protecting individual roosts impractical during large-scale management activities. We created a predictive spatial model of summer roosting habitat to identify important predictors using the presence-only modeling program MaxEnt and an information theoretic approach for model comparison. Two of 26 candidate models together accounted for >0.93 of AICc weights. Elevation and forest type were top predictors of presence; aspect north/south and distance-to-ridge were also important. The final average best model indicated that 5% of the study area was suitable habitat and 0.5% was optimal. This model matched our field observations that, in the southern Appalachian Mountains, optimal roosting habitat for M. sodalis is near the ridge top in south-facing mixed pine-hardwood forests at elevations from 260-575 m. Our findings, coupled with data from other studies, suggest M. sodalis is flexible in roost habitat selection across different ecoregions with varying topography and land use patterns. We caution that, while mature pine-hardwood forests are important now, specific areas of suitable and optimal habitat will change over time. Combining the information theoretic approach with presence-only models makes it possible to develop landscape-scale habitat suitability maps for forest bats. PMID:27115605

  13. A Presence-Only Model of Suitable Roosting Habitat for the Endangered Indiana Bat in the Southern Appalachians

    PubMed Central

    Aldrich, Stephen P.; Loeb, Susan C.

    2016-01-01

    We know little about how forest bats, which are cryptic and mobile, use roosts on a landscape scale. For widely distributed species like the endangered Indiana bat Myotis sodalis, identifying landscape-scale roost habitat associations will be important for managing the species in different regions where it occurs. For example, in the southern Appalachian Mountains, USA, M. sodalis roosts are scattered across a heavily forested landscape, which makes protecting individual roosts impractical during large-scale management activities. We created a predictive spatial model of summer roosting habitat to identify important predictors using the presence-only modeling program MaxEnt and an information theoretic approach for model comparison. Two of 26 candidate models together accounted for >0.93 of AICc weights. Elevation and forest type were top predictors of presence; aspect north/south and distance-to-ridge were also important. The final average best model indicated that 5% of the study area was suitable habitat and 0.5% was optimal. This model matched our field observations that, in the southern Appalachian Mountains, optimal roosting habitat for M. sodalis is near the ridge top in south-facing mixed pine-hardwood forests at elevations from 260–575 m. Our findings, coupled with data from other studies, suggest M. sodalis is flexible in roost habitat selection across different ecoregions with varying topography and land use patterns. We caution that, while mature pine-hardwood forests are important now, specific areas of suitable and optimal habitat will change over time. Combining the information theoretic approach with presence-only models makes it possible to develop landscape-scale habitat suitability maps for forest bats. PMID:27115605

  14. Predicting Species Distributions Using Record Centre Data: Multi-Scale Modelling of Habitat Suitability for Bat Roosts

    PubMed Central

    Bellamy, Chloe; Altringham, John

    2015-01-01

    Conservation increasingly operates at the landscape scale. For this to be effective, we need landscape scale information on species distributions and the environmental factors that underpin them. Species records are becoming increasingly available via data centres and online portals, but they are often patchy and biased. We demonstrate how such data can yield useful habitat suitability models, using bat roost records as an example. We analysed the effects of environmental variables at eight spatial scales (500 m – 6 km) on roost selection by eight bat species (Pipistrellus pipistrellus, P. pygmaeus, Nyctalus noctula, Myotis mystacinus, M. brandtii, M. nattereri, M. daubentonii, and Plecotus auritus) using the presence-only modelling software MaxEnt. Modelling was carried out on a selection of 418 data centre roost records from the Lake District National Park, UK. Target group pseudoabsences were selected to reduce the impact of sampling bias. Multi-scale models, combining variables measured at their best performing spatial scales, were used to predict roosting habitat suitability, yielding models with useful predictive abilities. Small areas of deciduous woodland consistently increased roosting habitat suitability, but other habitat associations varied between species and scales. Pipistrellus were positively related to built environments at small scales, and depended on large-scale woodland availability. The other, more specialist, species were highly sensitive to human-altered landscapes, avoiding even small rural towns. The strength of many relationships at large scales suggests that bats are sensitive to habitat modifications far from the roost itself. The fine resolution, large extent maps will aid targeted decision-making by conservationists and planners. We have made available an ArcGIS toolbox that automates the production of multi-scale variables, to facilitate the application of our methods to other taxa and locations. Habitat suitability modelling has

  15. Black-backed woodpecker habitat suitability mapping using conifer snag basal area estimated from airborne laser scanning

    NASA Astrophysics Data System (ADS)

    Casas Planes, Á.; Garcia, M.; Siegel, R.; Koltunov, A.; Ramirez, C.; Ustin, S.

    2015-12-01

    Occupancy and habitat suitability models for snag-dependent wildlife species are commonly defined as a function of snag basal area. Although critical for predicting or assessing habitat suitability, spatially distributed estimates of snag basal area are not generally available across landscapes at spatial scales relevant for conservation planning. This study evaluates the use of airborne laser scanning (ALS) to 1) identify individual conifer snags and map their basal area across a recently burned forest, and 2) map habitat suitability for a wildlife species known to be dependent on snag basal area, specifically the black-backed woodpecker (Picoides arcticus). This study focuses on the Rim Fire, a megafire that took place in 2013 in the Sierra Nevada Mountains of California, creating large patches of medium- and high-severity burned forest. We use forest inventory plots, single-tree ALS-derived metrics and Gaussian processes classification and regression to identify conifer snags and estimate their stem diameter and basal area. Then, we use the results to map habitat suitability for the black-backed woodpecker using thresholds for conifer basal area from a previously published habitat suitability model. Local maxima detection and watershed segmentation algorithms resulted in 75% detection of trees with stem diameter larger than 30 cm. Snags are identified with an overall accuracy of 91.8 % and conifer snags are identified with an overall accuracy of 84.8 %. Finally, Gaussian process regression reliably estimated stem diameter (R2 = 0.8) using height and crown area. This work provides a fast and efficient methodology to characterize the extent of a burned forest at the tree level and a critical tool for early wildlife assessment in post-fire forest management and biodiversity conservation.

  16. Mapping the climatic suitable habitat of oriental arborvitae (Platycladus orientalis) for introduction and cultivation at a global scale

    PubMed Central

    Li, Guoqing; Du, Sheng; Wen, Zhongming

    2016-01-01

    Oriental arborvitae (Platycladus orientalis) is an important afforestation and ornamental tree species, which is native in eastern Asian. Therefore, a global suitable habitat map for oriental arborvitae is urgently needed for global promotion and cultivation. Here, the potential habitat and climatic requirements of oriental arborvitae at global scale were simulated using herbariums data and 13 thermal-moisture variables as input data for maximum entropy model (MaxEnt). The simulation performance of MaxEnt is evaluated by ten-fold cross-validation and a jackknife procedure. Results show that the potential habitat and climate envelop of oriental arborvitae can be successfully simulated by MaxEnt at global scale, with a mean test AUC value of 0.93 and mean training AUC value of 0.95. Thermal factors play more important roles than moisture factors in controlling the distribution boundary of oriental arborvitae’s potential ranges. There are about 50 countries suitable for introduction and cultivation of oriental arborvitae with an area of 2.0 × 107 km2, which occupied 13.8% of land area on the earth. This unique study will provide valuable information and insights needed to identify new regions with climatically suitable habitats for cultivation and introduction of oriental arborvitae around the world. PMID:27443221

  17. Mapping the climatic suitable habitat of oriental arborvitae (Platycladus orientalis) for introduction and cultivation at a global scale.

    PubMed

    Li, Guoqing; Du, Sheng; Wen, Zhongming

    2016-01-01

    Oriental arborvitae (Platycladus orientalis) is an important afforestation and ornamental tree species, which is native in eastern Asian. Therefore, a global suitable habitat map for oriental arborvitae is urgently needed for global promotion and cultivation. Here, the potential habitat and climatic requirements of oriental arborvitae at global scale were simulated using herbariums data and 13 thermal-moisture variables as input data for maximum entropy model (MaxEnt). The simulation performance of MaxEnt is evaluated by ten-fold cross-validation and a jackknife procedure. Results show that the potential habitat and climate envelop of oriental arborvitae can be successfully simulated by MaxEnt at global scale, with a mean test AUC value of 0.93 and mean training AUC value of 0.95. Thermal factors play more important roles than moisture factors in controlling the distribution boundary of oriental arborvitae's potential ranges. There are about 50 countries suitable for introduction and cultivation of oriental arborvitae with an area of 2.0 × 10(7) km(2), which occupied 13.8% of land area on the earth. This unique study will provide valuable information and insights needed to identify new regions with climatically suitable habitats for cultivation and introduction of oriental arborvitae around the world. PMID:27443221

  18. Mapping the climatic suitable habitat of oriental arborvitae (Platycladus orientalis) for introduction and cultivation at a global scale

    NASA Astrophysics Data System (ADS)

    Li, Guoqing; Du, Sheng; Wen, Zhongming

    2016-07-01

    Oriental arborvitae (Platycladus orientalis) is an important afforestation and ornamental tree species, which is native in eastern Asian. Therefore, a global suitable habitat map for oriental arborvitae is urgently needed for global promotion and cultivation. Here, the potential habitat and climatic requirements of oriental arborvitae at global scale were simulated using herbariums data and 13 thermal-moisture variables as input data for maximum entropy model (MaxEnt). The simulation performance of MaxEnt is evaluated by ten-fold cross-validation and a jackknife procedure. Results show that the potential habitat and climate envelop of oriental arborvitae can be successfully simulated by MaxEnt at global scale, with a mean test AUC value of 0.93 and mean training AUC value of 0.95. Thermal factors play more important roles than moisture factors in controlling the distribution boundary of oriental arborvitae’s potential ranges. There are about 50 countries suitable for introduction and cultivation of oriental arborvitae with an area of 2.0 × 107 km2, which occupied 13.8% of land area on the earth. This unique study will provide valuable information and insights needed to identify new regions with climatically suitable habitats for cultivation and introduction of oriental arborvitae around the world.

  19. Range Measurement and a Habitat Suitability Map for the Norway Rat in a Highly Developed Urban Environment

    PubMed Central

    Oyedele, Dauda Taofik; Sah, Shahrul Anuar Mohd; Kairuddinand, Liyana; Wan Ibrahim, Wan Mohd Muhiyuddin

    2015-01-01

    Studies of habitat suitability (HS) are essential when animals’ habitats have been altered or when animals migrate to a habitat different from their natural habitat. This study assessed HS and used an integrated geographic information system in the assessment of Rattus norvegicus in a highly developed urban environment. Using data from the Campbell market and the police quarters of George Town, Malaysia, home range (through the use of 100% Minimum Convex Polygon [MCP], 95% MCP and 95% Harmonic Mean [HM]) was estimated. Home range for male rats at Campbell market reached an asymptote, with a slight increase, at 96 radio fixes (home range = 133.52 m2; core area = 29.39 m2). Female rats reached an asymptote at 62 radio fixes (home range = 13.38 m2; core area = 9.17 m2). At Campbell market, male rats emerged at 1900 hours every day, whereas females emerged at 2000 hours; at police quarters, the most common time of emergence for males was 2000 hours and for females was 2200. Raster charts of R. norvegicus showed that rat hot spots can be grouped into 4 zones (market, shop houses, settlement and general places). The standardised raster chart isolated the market as the major rallying points of the rats (hot spots) by producing the highest rats frequencies of 255. All of the habitat suitability thresholds, including the built-up points, skip bins, water source and nature of the site explored in this study, produced a structural pattern (monotonic increase or decrease) of habitat suitability. PMID:26868708

  20. Habitat Suitability analysis of Koklass (Pucrasia macrolopha) Pheasant in Churdhar Wildlife Sanctuary of Himachal Pradesh, India using Geospatial Technology

    NASA Astrophysics Data System (ADS)

    Eliza, K.; Sarma, K.

    2014-12-01

    Pheasants are at the brink of destruction due to degradation of forests, environmental pollution, climatic changes and extensive hunting of wild floras and faunas.The problem is more acute in the developing countries where wildlife and biodiversity conservation are often less prioritized due to more pressing demands of food security and poverty alleviation. Koklass Pheasant (Pucrasia macrolopha) species is distributed from Afghanistan and Pakistan in the east along the Himalayas to southeastern Tibet, western China and southeastern Mongolia.This species is grouped under endangered species in Red Data Book of Zoological Survey of India and also classified as least concern species according to IUCN Red List of Threatened Species.Conservation biologists and managers need a range of both classical analyses and specific modern tools to face the increasing threats to biodiversity. Among these tools, habitat-suitability modeling has recently emerged as a relevant technique to assess global impacts to define wide conservation priorities.The present study is carried out using remote sensing satellite imagery and GIS modeling technique for assessing habitat suitability of Koklass Pheasants and finding out the habitat factors influencing the Koklass distribution in Churdhar Wildlife Sanctuary, India. Effective management and conservation of wildlife populations and their habitats largely depend on our ability to understand and predict species-habitat interactions. Different thematic maps viz., land use/cover, forest types, drainage buffer, multiple ring buffers of sighting locations and multiple ring buffers of roads have been prepared to support the objective of the study. The Weighted Overlay Analysis model is used for identifying different potential areas of habitat for this endangered species. The most suitable area for Koklass Pheasant within the Wildlife Sanctuary is found to be about 23.8 percent of the total area which is due to favourable habitat conditions for the

  1. Shifts in the suitable habitat available for brown trout (Salmo trutta L.) under short-term climate change scenarios.

    PubMed

    Muñoz-Mas, R; Lopez-Nicolas, A; Martínez-Capel, F; Pulido-Velazquez, M

    2016-02-15

    The impact of climate change on the habitat suitability for large brown trout (Salmo trutta L.) was studied in a segment of the Cabriel River (Iberian Peninsula). The future flow and water temperature patterns were simulated at a daily time step with M5 models' trees (NSE of 0.78 and 0.97 respectively) for two short-term scenarios (2011-2040) under the representative concentration pathways (RCP 4.5 and 8.5). An ensemble of five strongly regularized machine learning techniques (generalized additive models, multilayer perceptron ensembles, random forests, support vector machines and fuzzy rule base systems) was used to model the microhabitat suitability (depth, velocity and substrate) during summertime and to evaluate several flows simulated with River2D©. The simulated flow rate and water temperature were combined with the microhabitat assessment to infer bivariate habitat duration curves (BHDCs) under historical conditions and climate change scenarios using either the weighted usable area (WUA) or the Boolean-based suitable area (SA). The forecasts for both scenarios jointly predicted a significant reduction in the flow rate and an increase in water temperature (mean rate of change of ca. -25% and +4% respectively). The five techniques converged on the modelled suitability and habitat preferences; large brown trout selected relatively high flow velocity, large depth and coarse substrate. However, the model developed with support vector machines presented a significantly trimmed output range (max.: 0.38), and thus its predictions were banned from the WUA-based analyses. The BHDCs based on the WUA and the SA broadly matched, indicating an increase in the number of days with less suitable habitat available (WUA and SA) and/or with higher water temperature (trout will endure impoverished environmental conditions ca. 82% of the days). Finally, our results suggested the potential extirpation of the species from the study site during short time spans. PMID:26674698

  2. Production of fiberglass/metal composite material suitable for building habitat and manufacturing facilities

    NASA Technical Reports Server (NTRS)

    1987-01-01

    The production of a fiberglass/metal composite material suitable for building habitats and manufacturing facilities was the project for Clemson. The concept and development of the knowledge necessary to produce glass fibers originated in the spring semester. During the summer, while at Johnson Space Center, fiberglass from a rock composition similar to ones found at the Apollo 16 site on the moon was successfully produced. The project this year was a continuation of last year's studies. We addressed the following problems which emerged as the work progressed: (1) Methods for coating the fibers with a metal were explored. We manufactured composites in two stages: Glass fibers without any coating on them; and fibers coated with metals as they were made. This proved to be a difficult process. Future activities include using a chemical vapor deposition process on fibers which have been made. (2) A glass furnace was developed which relies primarily on solar energy for melting the glass. The temperature of the melted glass is maintained by electrical means. The design is for 250 kg of glass per day. An electrical engineering student developed a scheme for controlling the melting and manufacturing process from the earth. This was done to minimize the human risk. Graphite refractories are relied on to contain the melt. (3) The glass composition chosen for the project is a relatively pure anorthite which is available in the highland regions of the lunar surface. A major problems with this material is that it melts at a comparatively high temperature. This problem will be solved by using graphite refractory materials for the furnace. The advantage of this glass composition is that it is very stable and does not tend to crystallize. (4) We have also refined the experimental furnace and fiber making machinery which we will be using at Johnson Space Center this summer. We believe that we will be able to draw and coat glass fibers in a vacuum for use in composites. We intend to

  3. Managing Environmental Flows for Impounded Rivers in Semi-Arid Regions- A Habitat Suitability Index (HSI) Approach for the Assessment of River Habitat for Salmonid Populations

    NASA Astrophysics Data System (ADS)

    Pai, H.; Sivakumaran, K.; Villamizar, S. R.; Flanagan, J.; Guo, Q.; Harmon, T. C.

    2013-12-01

    Balancing ecosystem health in water-scarce, agriculturally dominated river basins remains a challenge. In dry water years, maintaining conditions for restored and sustained indigenous fish populations (a frequently used indicator for ecosystem health) is particularly challenging. Competing human demands include urban and agricultural water supplies, hydropower, and flood control. In many semi-arid regions, increasing drought intensity and frequency under future climate scenarios will combine with population increases to water scarcity. The goal of this work is to better understand how reservoir releases affect fish habitat and overall river aquatic ecosystem quality. Models integrating a diverse array of physical and biological processes and system state are used to forecast the river ecosystem response to changing drivers. We propose a distributed parameter-based Habitat Suitability Index (HSI) approach for assessing fish habitat quality. Our river ecosystem HSI maps are based on a combination of the following: (1) In situ data describing stream flow and water quality conditions; (2) Spatial observations, including surveyed cross-sections, aerial imagery and digital elevation maps (DEM) of the river and its riparian corridor; and (3) Simulated spatially distributed water depths, flow velocities, and temperatures estimated from 1D and 2D river flow and temperature models (HEC-RAS and CE-QUAL-W2, respectively). With respect to (2), image processing schemes are used to classify and map key habitat features, namely riparian edge and shallow underwater vegetation. HSI maps can be modified temporally to address specific life cycle requirements of indicator fish species. Results are presented for several reaches associated with the San Joaquin River Restoration Project, focusing on several components of the Chinook salmon life cycle. HSI maps and interpretations are presented in the context of a range of prescribed reservoir release hydrographs linked to California water

  4. Relative Effects of Road Risk, Habitat Suitability, and Connectivity on Wildlife Roadkills: The Case of Tawny Owls (Strix aluco)

    PubMed Central

    Santos, Sara M.; Lourenço, Rui; Mira, António; Beja, Pedro

    2013-01-01

    Background Despite its importance for reducing wildlife-vehicle collisions, there is still incomplete understanding of factors responsible for high road mortality. In particular, few empirical studies examined the idea that spatial variation in roadkills is influenced by a complex interplay between road-related factors, and species-specific habitat quality and landscape connectivity. Methodology/Principal Findings In this study we addressed this issue, using a 7-year dataset of tawny owl (Strix aluco) roadkills recorded along 37 km of road in southern Portugal. We used a multi-species roadkill index as a surrogate of intrinsic road risk, and we used a Maxent distribution model to estimate habitat suitability. Landscape connectivity was estimated from least-cost paths between tawny owl territories, using habitat suitability as a resistance surface. We defined 10 alternative scenarios to compute connectivity, based on variation in potential movement patterns according to territory quality and dispersal distance thresholds. Hierarchical partitioning of a regression model indicated that independent variation in tawny owl roadkills was explained primarily by the roadkill index (70.5%) and, to a much lesser extent, by landscape connectivity (26.2%), while habitat suitability had minor effects (3.3%). Analysis of connectivity scenarios suggested that owl roadkills were primarily related to short range movements (<5 km) between high quality territories. Tawny owl roadkills were spatially autocorrelated, but the introduction of spatial filters in the regression model did not change the type and relative contribution of environmental variables. Conclusions Overall, results suggest that road-related factors may have a dominant influence on roadkill patterns, particularly in areas like ours where habitat quality and landscape connectivity are globally high for the study species. Nevertheless, the study supported the view that functional connectivity should be incorporated

  5. Predicting habitat suitability and geographic distribution of anchovy (Engraulis ringens) due to climate change in the coastal areas off Chile

    NASA Astrophysics Data System (ADS)

    Silva, Claudio; Andrade, Isabel; Yáñez, Eleuterio; Hormazabal, Samuel; Barbieri, María Ángela; Aranis, Antonio; Böhm, Gabriela

    2016-08-01

    The effects of climate change on ocean conditions will have impacts on fish stocks, primarily through physiological and behavioural effects, such as changes in growth, reproduction, mortality and distribution. Habitat and distribution predictions for marine fishery species under climate change scenarios are important for understanding the overall impacts of such global changes on the human society and on the ecosystem. In this study, we examine the impacts of climate change on anchovy fisheries off Chile using predicted changes in global models according to the National Centre for Atmospheric Research (NCAR) Community Climate System Model 3.0 (CCSM3) and IPCC high future CO2 emission scenario A2, habitat suitability index (HSI) models and satellite-based sea surface temperature (SST) and chlorophyll-a (Chl-a) estimates from high-resolution regional models for the simulation period 2015-2065. Predictions of SST from global climate models were regionalised using the Delta statistical downscaling technique. Predictions of chlorophyll-a were developed using historical Chl-a and SST (2003-2013) satellite data and applying a harmonic model. The results show an increase in SST of up to 2.5 °C by 2055 in the north and central-south area for an A2 scenario. The habitat suitability index model was developed using historical (2001-2011) monthly fisheries and environmental data. The catch per unit effort (CPUE) was used as an abundance index in developing the HSI models and was calculated as the total catch (ton) by hold capacity (m3) in a 10‧ × 10‧ fishing grid square of anchovy, integrated over one month of fishing activity. The environmental data included the distance to coast (DC), thermal (SST) and food availability (Chl-a) conditions. The HSI modelling consists of estimating SI curves based on available evidence regarding the optimum range of environmental conditions for anchovy and estimating an integrated HSI using the Arithmetic Mean Model (AMM) method. The

  6. Higher mobility of butterflies than moths connected to habitat suitability and body size in a release experiment.

    PubMed

    Kuussaari, Mikko; Saarinen, Matias; Korpela, Eeva-Liisa; Pöyry, Juha; Hyvönen, Terho

    2014-10-01

    Mobility is a key factor determining lepidopteran species responses to environmental change. However, direct multispecies comparisons of mobility are rare and empirical comparisons between butterflies and moths have not been previously conducted. Here, we compared mobility between butterflies and diurnal moths and studied species traits affecting butterfly mobility. We experimentally marked and released 2011 butterfly and 2367 moth individuals belonging to 32 and 28 species, respectively, in a 25 m × 25 m release area within an 11-ha, 8-year-old set-aside field. Distance moved and emigration rate from the release habitat were recorded by species. The release experiment produced directly comparable mobility data in 18 butterfly and 9 moth species with almost 500 individuals recaptured. Butterflies were found more mobile than geometroid moths in terms of both distance moved (mean 315 m vs. 63 m, respectively) and emigration rate (mean 54% vs. 17%, respectively). Release habitat suitability had a strong effect on emigration rate and distance moved, because butterflies tended to leave the set-aside, if it was not suitable for breeding. In addition, emigration rate and distance moved increased significantly with increasing body size. When phylogenetic relatedness among species was included in the analyses, the significant effect of body size disappeared, but habitat suitability remained significant for distance moved. The higher mobility of butterflies than geometroid moths can largely be explained by morphological differences, as butterflies are more robust fliers. The important role of release habitat suitability in butterfly mobility was expected, but seems not to have been empirically documented before. The observed positive correlation between butterfly size and mobility is in agreement with our previous findings on butterfly colonization speed in a long-term set-aside experiment and recent meta-analyses on butterfly mobility. PMID:25614794

  7. Assessing shoreline exposure and oyster habitat suitability maximizes potential success for sustainable shoreline protection using restored oyster reefs.

    PubMed

    La Peyre, Megan K; Serra, Kayla; Joyner, T Andrew; Humphries, Austin

    2015-01-01

    Oyster reefs provide valuable ecosystem services that contribute to coastal resilience. Unfortunately, many reefs have been degraded or removed completely, and there are increased efforts to restore oysters in many coastal areas. In particular, much attention has recently been given to the restoration of shellfish reefs along eroding shorelines to reduce erosion. Such fringing reef approaches, however, often lack empirical data to identify locations where reefs are most effective in reducing marsh erosion, or fully take into account habitat suitability. Using monitoring data from 5 separate fringing reef projects across coastal Louisiana, we quantify shoreline exposure (fetch + wind direction + wind speed) and reef impacts on shoreline retreat. Our results indicate that fringing oyster reefs have a higher impact on shoreline retreat at higher exposure shorelines. At higher exposures, fringing reefs reduced marsh edge erosion an average of 1.0 m y(-1). Using these data, we identify ranges of shoreline exposure values where oyster reefs are most effective at reducing marsh edge erosion and apply this knowledge to a case study within one Louisiana estuary. In Breton Sound estuary, we calculate shoreline exposure at 500 random points and then overlay a habitat suitability index for oysters. This method and the resulting visualization show areas most likely to support sustainable oyster populations as well as significantly reduce shoreline erosion. Our results demonstrate how site selection criteria, which include shoreline exposure and habitat suitability, are critical to ensuring greater positive impacts and longevity of oyster reef restoration projects. PMID:26500825

  8. Assessing shoreline exposure and oyster habitat suitability maximizes potential success for sustainable shoreline protection using restored oyster reefs

    PubMed Central

    Serra, Kayla; Joyner, T. Andrew; Humphries, Austin

    2015-01-01

    Oyster reefs provide valuable ecosystem services that contribute to coastal resilience. Unfortunately, many reefs have been degraded or removed completely, and there are increased efforts to restore oysters in many coastal areas. In particular, much attention has recently been given to the restoration of shellfish reefs along eroding shorelines to reduce erosion. Such fringing reef approaches, however, often lack empirical data to identify locations where reefs are most effective in reducing marsh erosion, or fully take into account habitat suitability. Using monitoring data from 5 separate fringing reef projects across coastal Louisiana, we quantify shoreline exposure (fetch + wind direction + wind speed) and reef impacts on shoreline retreat. Our results indicate that fringing oyster reefs have a higher impact on shoreline retreat at higher exposure shorelines. At higher exposures, fringing reefs reduced marsh edge erosion an average of 1.0 m y−1. Using these data, we identify ranges of shoreline exposure values where oyster reefs are most effective at reducing marsh edge erosion and apply this knowledge to a case study within one Louisiana estuary. In Breton Sound estuary, we calculate shoreline exposure at 500 random points and then overlay a habitat suitability index for oysters. This method and the resulting visualization show areas most likely to support sustainable oyster populations as well as significantly reduce shoreline erosion. Our results demonstrate how site selection criteria, which include shoreline exposure and habitat suitability, are critical to ensuring greater positive impacts and longevity of oyster reef restoration projects. PMID:26500825

  9. Modeling suitable habitat of invasive red lionfish Pterois volitans (Linnaeus, 1758) in North and South America’s coastal waters

    USGS Publications Warehouse

    Evangelista, Paul H.; Young, Nicholas E.; Schofield, Pamela J.; Jarnevich, Catherine S.

    2016-01-01

    We used two common correlative species-distribution models to predict suitable habitat of invasive red lionfish Pterois volitans (Linnaeus, 1758) in the western Atlantic and eastern Pacific Oceans. The Generalized Linear Model (GLM) and the Maximum Entropy (Maxent) model were applied using the Software for Assisted Habitat Modeling. We compared models developed using native occurrences, using non-native occurrences, and using both native and non-native occurrences. Models were trained using occurrence data collected before 2010 and evaluated with occurrence data collected from the invaded range during or after 2010. We considered a total of 22 marine environmental variables. Models built with non-native only or both native and non-native occurrence data outperformed those that used only native occurrences. Evaluation metrics based on the independent test data were highest for models that used both native and non-native occurrences. Bathymetry was the strongest environmental predictor for all models and showed increasing suitability as ocean floor depth decreased, with salinity ranking the second strongest predictor for models that used native and both native and non-native occurrences, indicating low habitat suitability for salinities <30. Our model results also suggest that red lionfish could continue to invade southern latitudes in the western Atlantic Ocean and may establish localized populations in the eastern Pacific Ocean. We reiterate the importance in the choice of the training data source (native, non-native, or native/non-native) used to develop correlative species distribution models for invasive species.

  10. Development and Application of a Habitat Suitability Ranking Model for the New Mexico Meadow Jumping Mouse (Zapus hudsonius luteus)

    SciTech Connect

    James Biggs; Mary Mullen; Kathryn Bennett

    1999-11-01

    The New Mexico meadow jumping mouse (Zapus hudsonius luteus) is currently listed as a state threatened species in New Mexico and has been identified as potentially occurring within the Los Alamos National Laboratory (LANL) boundary. We describe the development of a model to identify and rank habitat at LANL that may be suitable for occupation by this species. The model calculates a habitat suitability ranking (HSR) based on total plant cover, plant species composition, total number of plant species, and plant height. Input data for the model is based on the measurement of these variables at known locations where this species has been found within the Jemez Mountains. Model development included the selection of habitat variables, developing a probability distribution for each variable, and applying weights to each variable based on their overall importance in defining the suitability of the habitat. The habitat variables (HV) include plant cover (HV1), grass/forb cover (HV2), plant height (HV3), number of forbs (HV4), number of grasses (HV5), and sedge/rush cover (HV6). Once the HVs were selected, probability values were calculated for each. Each variable was then assigned a ''weighting factor'' to reflect the variables' importance relative to one another with respect to contribution to quality of habitat. The least important variable, sedge/rush cover, was assigned a weight factor of ''1'' with increasing values assigned to each remaining variable as follows: number of forbs = 3, number of grasses = 3, plant height = 5, grass/forb cover = 6, and total plant cover = 7. Based on the probability values and weighting factors, a HSR is calculated as follows: HSR = (P{sub HV1}(7) + P{sub HV2}(6) + P{sub HV3}(5) + P{sub HV4}(3) + P{sub HV5}(3) + P{sub HV6}(1)). Once calculated, the HSR values are placed into one of four habitat categorical groupings by which management strategies are applied.

  11. High Variance within Salmonid Spawning Gravels at Restoration Sites Creates More Suitable Habitat within the Hyporheic Zone

    NASA Astrophysics Data System (ADS)

    Janes, M. K.; Heffernan, J. E.; Rosenberry, J. W.; Horner, T.

    2012-12-01

    The Lower American River has historically provided natural spawning habitat for approximately one third of Northern California's salmon population. However, since the construction of Folsom and Nimbus Dams, downstream reaches have become sediment starved and periodic high outflow from the dam has caused channel armoring and incision, thereby degrading the natural spawning habitat. Restoration work on spawning sites in the Lower American River has consisted primarily of importing gravel to create riffles during periods of moderate flow. This is an effort to mitigate armoring of the riverbed and to rehabilitate salmonid spawning habitat by providing suitable grain size for all stages of spawning (redd construction, incubation, and emergence). Since restoration activities began, all rehabilitated sites have not been equally used for spawning. This study attempts to examine and compare the physical properties of each site in order to ascertain which characteristics create more suitable rehabilitated habitat. To do this, we compared restored areas to pre-restoration conditions through the assessment of three main aspects of the restored spawning habitat; grain size and its natural mobility, water flow in the surface and subsurface, and intragravel water quality. We found that some augmentation sites are more heterogeneous than others, and this correlates with higher spawning use. Most spawning was at fin height, and salmonids tend to use sites with higher depth variance (surface features) and higher variance in flow directions and velocities. With time, salmonids alter the spawning sites, creating small ridges and valleys perpendicular to flow. This creates more variable subsurface flow and generates hyporheic flow through the new gravel. This may have an effect on spawning as the more seasoned additions have a higher frequency of spawning than the newer augmentations. In order to efficiently rehabilitate a site and expedite the "seasoning process", creating variance

  12. PREDICTING HABITAT SUITABILITY FOR TWO BREEDS OF CATTLE (ENGLISH AND SPANISH) IN NORTHEASTERN OREGON PRAIRIE ECOSYSTEMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eastern Oregon cattle distribution was studied with global positioning (GPS) collars for 2 years on the Zumwalt prairie in the spring and fall and Hells Canyon during the winter to determine distribution and habitat selection differences between Spanish bred (Corriente X Longhorn) and English bred c...

  13. A GIS-BASED WETLAND ASESSMENT MODEL FOR PREDICTING AVIAN HABITAT SUITABILITY UNDER UNCERTAINTY

    EPA Science Inventory

    The Farmington Bay region of the Great Salt Lake is fringed with an array of wetland complexes providing critical avian habitat. Land use and hydrological changes resulting from projected urban population increases and combined with the low topographical relief of the lake basin...

  14. Minimum tailwater flows in relation to habitat suitability and sport-fish harvest

    USGS Publications Warehouse

    Jacobs, K.E.; Swink, W.D.; Novotny, J.F.

    1987-01-01

    The instream flow needs of four sport fishes (rainbow trout Salmo gairdneri, channel catfish Ictalurus punctatus, smallmouth bass Micropterus dolomieui, and white crappie Pomoxis annularis) were evaluated in the tailwater below Green River Lake, Kentucky. The Newcombe method, a simple procedure developed in British Columbia that is based on the distribution of water depths and velocities at various flows, was used to predict usable habitat at seven flows. Predicted usable habitat was two to six times greater for rainbow trout than for any of the other species at all flows. Angler harvest corresponded to the predicted abundance for rainbow trout and smallmouth bass, but the catch of channel catfish and white crappies was seasonally greater than expected. The presence of the dam and reservoir apparently disrupted the normal movement and feeding patterns of these species and periodically overrode the relation between usable habitat and abundance assumed in the Newcombe method. The year-round minimum flow of 4.6 m 3/s recommended for the tailwater would generally increase the amount of habitat available in the tailwater from April through October, and the minimum flow of 2.4 m3/s recommended for periods of drought would allow the maintenance of a trout fishery.

  15. Prostate cancer: a serious disease suitable for prevention.

    PubMed

    Fitzpatrick, John M; Schulman, Claude; Zlotta, Alexandre R; Schröder, Fritz H

    2009-04-01

    Prostate cancer is among the most common causes of death from cancer in men, and accounts for 10% of all new male cancers worldwide. The diagnosis and treatment of prostate cancer place a substantial physical and emotional burden on patients and their families, and have considerable financial implications for healthcare providers and society. Given that the risk of prostate cancer continues to increase with age, the burden of the disease is likely to increase in line with population life-expectancy. Reducing the risk of prostate cancer has gained increasing coverage in recent years, with proof of principle shown in the Prostate Cancer Prevention Trial with the type 2 5alpha-reductase (5AR) inhibitor, finasteride. The long latency period, high disease prevalence, and significant associated morbidity and mortality make prostate cancer a suitable target for a risk-reduction approach. Several agents are under investigation for reducing the risk of prostate cancer, including selenium/vitamin E and selective oestrogen receptors modulators (e.g. toremifene). In addition, the Reduction by Dutasteride of Prostate Cancer Events trial, involving >8000 men, is evaluating the effect of the dual 5AR inhibitor, dutasteride, on the risk of developing prostate cancer. A successful risk-reduction strategy might decrease the incidence of the disease, as well as the anxiety, cost and morbidity associated with its diagnosis and treatment. PMID:19302133

  16. Impact of the Gezhouba and Three Gorges Dams on habitat suitability of carps in the Yangtze River

    NASA Astrophysics Data System (ADS)

    Yi, Yujun; Wang, Zhaoyin; Yang, Zhifeng

    2010-06-01

    SummaryThe Gezhouba Dam and Three Gorges Project are the two largest hydraulic projects in the middle reach of the Yangtze River. Although these projects have yielded benefits to local communities by providing flood control, water supply, and safe navigation, they also have changed the physical habitat of the Yangtze River. As a consequence, aquatic organisms, including rare species and fishes with economic value, have been affected. The Yangtze River's four major carp species (YFMCS)—black carp ( Mylopharyngodon piceus), grass carp ( Ctenop haryngodon idellus), silver carp ( Hypoph thal michthys molitrix), and big-head carp ( Aristichyths nobilis)—have significant importance to the fresh water fishery in China. According to field surveys, the percentage of the YFMCS in the total catch of fish from Tongting Lake has gradually reduced. The percentages were 22%, 14.1%, 11.84%, and 8.5% in 1963, 1980-1982, 1997, and 2002, respectively. These reductions in species population are mainly attributed to the loss of spawning ground caused by dam construction. Considering the spawning characteristics of the YFMCS, a habitat suitability index model (HSI) has been established. A one-dimensional (1-D) mathematical model was also developed to simulate and predict aspects of the physical habitat situation for the YFMCS. By coupling the habitat suitability curves and the 1-D mathematical model, a HSI model for the YFMCS was established. The HSI model was validated by comparing measured data with predictions from the model. These comparisons show that the computed results agree well with the measured results. The HSI model for the YFMCS is used to suggest a minimum instream flow and suitable daily discharge increase during the reproduction season for the carp species. The minimum discharge needed for the YFMCS in the middle reach of the Yangtze River is 3000 m 3/s. Different daily discharge increases are required for different initial discharges, too small or too large of an

  17. Asian elephants in China: estimating population size and evaluating habitat suitability.

    PubMed

    Zhang, Li; Dong, Lu; Lin, Liu; Feng, Limin; Yan, Fan; Wang, Lanxin; Guo, Xianming; Luo, Aidong

    2015-01-01

    We monitored the last remaining Asian elephant populations in China over the past decade. Using DNA tools and repeat genotyping, we estimated the population sizes from 654 dung samples collected from various areas. Combined with morphological individual identifications from over 6,300 elephant photographs taken in the wild, we estimated that the total Asian elephant population size in China is between 221 and 245. Population genetic structure and diversity were examined using a 556-bp fragment of mitochondrial DNA, and 24 unique haplotypes were detected from DNA analysis of 178 individuals. A phylogenetic analysis revealed two highly divergent clades of Asian elephants, α and β, present in Chinese populations. Four populations (Mengla, Shangyong, Mengyang, and Pu'Er) carried mtDNA from the α clade, and only one population (Nangunhe) carried mtDNA belonging to the β clade. Moreover, high genetic divergence was observed between the Nangunhe population and the other four populations; however, genetic diversity among the five populations was low, possibly due to limited gene flow because of habitat fragmentation. The expansion of rubber plantations, crop cultivation, and villages along rivers and roads had caused extensive degradation of natural forest in these areas. This had resulted in the loss and fragmentation of elephant habitats and had formed artificial barriers that inhibited elephant migration. Using Geographic Information System, Global Positioning System, and Remote Sensing technology, we found that the area occupied by rubber plantations, tea farms, and urban settlements had dramatically increased over the past 40 years, resulting in the loss and fragmentation of elephant habitats and forming artificial barriers that inhibit elephant migration. The restoration of ecological corridors to facilitate gene exchange among isolated elephant populations and the establishment of cross-boundary protected areas between China and Laos to secure their natural

  18. Asian Elephants in China: Estimating Population Size and Evaluating Habitat Suitability

    PubMed Central

    Zhang, Li; Dong, Lu; Lin, Liu; Feng, Limin; Yan, Fan; Wang, Lanxin; Guo, Xianming; Luo, Aidong

    2015-01-01

    We monitored the last remaining Asian elephant populations in China over the past decade. Using DNA tools and repeat genotyping, we estimated the population sizes from 654 dung samples collected from various areas. Combined with morphological individual identifications from over 6,300 elephant photographs taken in the wild, we estimated that the total Asian elephant population size in China is between 221 and 245. Population genetic structure and diversity were examined using a 556-bp fragment of mitochondrial DNA, and 24 unique haplotypes were detected from DNA analysis of 178 individuals. A phylogenetic analysis revealed two highly divergent clades of Asian elephants, α and β, present in Chinese populations. Four populations (Mengla, Shangyong, Mengyang, and Pu’Er) carried mtDNA from the α clade, and only one population (Nangunhe) carried mtDNA belonging to the β clade. Moreover, high genetic divergence was observed between the Nangunhe population and the other four populations; however, genetic diversity among the five populations was low, possibly due to limited gene flow because of habitat fragmentation. The expansion of rubber plantations, crop cultivation, and villages along rivers and roads had caused extensive degradation of natural forest in these areas. This had resulted in the loss and fragmentation of elephant habitats and had formed artificial barriers that inhibited elephant migration. Using Geographic Information System, Global Positioning System, and Remote Sensing technology, we found that the area occupied by rubber plantations, tea farms, and urban settlements had dramatically increased over the past 40 years, resulting in the loss and fragmentation of elephant habitats and forming artificial barriers that inhibit elephant migration. The restoration of ecological corridors to facilitate gene exchange among isolated elephant populations and the establishment of cross-boundary protected areas between China and Laos to secure their natural

  19. Habitat suitability mapping of Anopheles darlingi in the surroundings of the Manso hydropower plant reservoir, Mato Grosso, Central Brazil

    PubMed Central

    Zeilhofer, Peter; Santos, Emerson Soares dos; Ribeiro, Ana LM; Miyazaki, Rosina D; Santos, Marina Atanaka dos

    2007-01-01

    Background Hydropower plants provide more than 78 % of Brazil's electricity generation, but the country's reservoirs are potential new habitats for main vectors of malaria. In a case study in the surroundings of the Manso hydropower plant in Mato Grosso state, Central Brazil, habitat suitability of Anopheles darlingi was studied. Habitat profile was characterized by collecting environmental data. Remote sensing and GIS techniques were applied to extract additional spatial layers of land use, distance maps, and relief characteristics for spatial model building. Results Logistic regression analysis and ROC curves indicate significant relationships between the environment and presence of An. darlingi. Probabilities of presence strongly vary as a function of land cover and distance from the lake shoreline. Vector presence was associated with spatial proximity to reservoir and semi-deciduous forests followed by Cerrado woodland. Vector absence was associated with open vegetation formations such as grasslands and agricultural areas. We suppose that non-significant differences of vector incidences between rainy and dry seasons are associated with the availability of anthropogenic breeding habitat of the reservoir throughout the year. Conclusion Satellite image classification and multitemporal shoreline simulations through DEM-based GIS-analyses consist in a valuable tool for spatial modeling of A. darlingi habitats in the studied hydropower reservoir area. Vector presence is significantly increased in forested areas near reservoirs in bays protected from wind and wave action. Construction of new reservoirs under the tropical, sub-humid climatic conditions should therefore be accompanied by entomologic studies to predict the risk of malaria epidemics. PMID:17343728

  20. Suitable Environmental Ranges for Potential Coral Reef Habitats in the Tropical Ocean

    PubMed Central

    Guan, Yi; Hohn, Sönke; Merico, Agostino

    2015-01-01

    Coral reefs are found within a limited range of environmental conditions or tolerance limits. Estimating these limits is a critical prerequisite for understanding the impacts of climate change on the biogeography of coral reefs. Here we used the diagnostic model ReefHab to determine the current environmental tolerance limits for coral reefs and the global distribution of potential coral reef habitats as a function of six factors: temperature, salinity, nitrate, phosphate, aragonite saturation state, and light. To determine these tolerance limits, we extracted maximum and minimum values of all environmental variables in corresponding locations where coral reefs are present. We found that the global, annually averaged tolerance limits for coral reefs are 21.7—29.6 °C for temperature, 28.7—40.4 psu for salinity, 4.51 μmol L-1 for nitrate, 0.63 μmol L-1 for phosphate, and 2.82 for aragonite saturation state. The averaged minimum light intensity in coral reefs is 450 μmol photons m-2 s-1. The global area of potential reef habitats calculated by the model is 330.5 × 103 km2. Compared with previous studies, the tolerance limits for temperature, salinity, and nutrients have not changed much, whereas the minimum value of aragonite saturation in coral reef waters has decreased from 3.28 to 2.82. The potential reef habitat area calculated with ReefHab is about 121×103 km2 larger than the area estimated from the charted reefs, suggesting that the growth potential of coral reefs is higher than currently observed. PMID:26030287

  1. Habitat suitability for brook trout (Salvelinus fontinalis) reproduction in Adirondack Lakes

    NASA Astrophysics Data System (ADS)

    Schofield, Carl L.

    1993-04-01

    The relationships between habitat characteristics and reproductive status of Adirondack brook trout populations were examined utilizing the Adirondack Lake Survey Corporation data base, which includes physical, chemical, and biological data for 1469 lakes. The only variables strongly related to brook trout natural reproduction were indices of groundwater influence on surface water chemistry, specifically silica and sodium concentrations. This finding supports the hypothesis that lake spawning populations of brook trout are strongly dependent on groundwater seepage for successful reproduction. Spawning habitat in small headwater lakes impounded by beaver activity may be degraded as a result of siltation of nearshore zones and diminished groundwater seepage. Adirondack lakes situated in thick-till basins receive proportionally greater groundwater input than thin-till lake types and thick-till lakes also had the highest proportion of self-sustaining brook trout populations. Acidification is most pronounced in thin-till basins, which also exhibited a low frequency of self-sustaining brook trout populations. Although brook trout fisheries may be maintained in acidic lakes by liming and stocking, the establishment of self-sustaining brook trout populations is not a likely outcome of these management practices. Additionally, there appears to be limited potential for restoration of lake spawning brook trout populations in currently acidic, fishless lakes should acidic inputs decline as a result of reductions in acid-forming emissions.

  2. The Chemical and Genetic Characteristics of Szechuan Pepper (Zanthoxylum bungeanum and Z. armatum) Cultivars and Their Suitable Habitat

    PubMed Central

    Xiang, Li; Liu, Yue; Xie, Caixiang; Li, Xiwen; Yu, Yadong; Ye, Meng; Chen, Shilin

    2016-01-01

    Szechuan peppers, famous for their unique sensation and flavor, are widely used as a food additive and traditional herbal medicine. Zanthoxylum bungeanum and Z. armatum are both commonly recognized as Szechuan peppers, but they have different tastes and effects. The chemical components, genetic characteristics, and suitable habitat of six cultivars were analyzed in this study. The results indicated that Z. armatum contained a larger proportion of volatile oil, whereas Z. bungeanum produced a more non-volatile ether extraction. The average content of volatile oil and non-volatile ether extract of Z. armatum were 11.84 and 11.63%, respectively, and the average content of volatile oil and non-volatile ether extract of Z. bungeanum were 6.46 and 14.23%, respectively. Combined with an internal transcribed spacer 2 (ITS2) sequence characters and chemical PCA results, six cultivars were classified into their own groups, for the two species in particular. The temperature in January and July were the most significant ecological factors influencing the contents of the Z. armatum volatile oil. However, annual precipitation, temperature in January and relevant humidity had a significant positive correlation with the content of non-volatile ether extract in Z. bungeanum. Thus, the most suitable areas for producing Z. bungeanum cultivars ranged from the Hengduan Mountains to the Ta-pa Mountains, and the regions suitable for Z. armatum cultivars were found to be in the Sichuan Basin and Dalou-Wu mountains. The predicted suitable habitat could be used as a preliminary test area for Szechuan pepper cultivar production. PMID:27148298

  3. A novel theory to explain species diversity in landscapes: positive frequency dependence and habitat suitability.

    PubMed Central

    Molofsky, Jane; Bever, James D

    2002-01-01

    Theories to explain the diversity of species have required that individual species occupy unique niches and/or vary in their response to environmental factors. Positive interactions within a species, although common in communities, have not been thought to maintain species diversity because in non-spatial models the more abundant species always outcompetes the rarer species. Here, we show, using a stochastic spatial model, that positive intraspecific interactions such as those caused by positive frequency dependence and/or priority effects, can maintain species diversity if interactions between individuals are primarily local and the habitat contains areas that cannot be colonized by any species, such as boulders or other physical obstructions. When intraspecific interactions are primarily neutral, species diversity will eventually erode to a single species. When the landscape is homogeneous (i.e. does not contain areas that cannot be colonized by any species), the presence of strong intraspecific interactions will not maintain diversity. PMID:12495479

  4. Deep-sea benthic megafaunal habitat suitability modelling: A global-scale maximum entropy model for xenophyophores

    NASA Astrophysics Data System (ADS)

    Ashford, Oliver S.; Davies, Andrew J.; Jones, Daniel O. B.

    2014-12-01

    Xenophyophores are a group of exclusively deep-sea agglutinating rhizarian protozoans, at least some of which are foraminifera. They are an important constituent of the deep-sea megafauna that are sometimes found in sufficient abundance to act as a significant source of habitat structure for meiofaunal and macrofaunal organisms. This study utilised maximum entropy modelling (Maxent) and a high-resolution environmental database to explore the environmental factors controlling the presence of Xenophyophorea and two frequently sampled xenophyophore species that are taxonomically stable: Syringammina fragilissima and Stannophyllum zonarium. These factors were also used to predict the global distribution of each taxon. Areas of high habitat suitability for xenophyophores were highlighted throughout the world's oceans, including in a large number of areas yet to be suitably sampled, but the Northeast and Southeast Atlantic Ocean, Gulf of Mexico and Caribbean Sea, the Red Sea and deep-water regions of the Malay Archipelago represented particular hotspots. The two species investigated showed more specific habitat requirements when compared to the model encompassing all xenophyophore records, perhaps in part due to the smaller number and relatively more clustered nature of the presence records available for modelling at present. The environmental variables depth, oxygen parameters, nitrate concentration, carbon-chemistry parameters and temperature were of greatest importance in determining xenophyophore distributions, but, somewhat surprisingly, hydrodynamic parameters were consistently shown to have low importance, possibly due to the paucity of well-resolved global hydrodynamic datasets. The results of this study (and others of a similar type) have the potential to guide further sample collection, environmental policy, and spatial planning of marine protected areas and industrial activities that impact the seafloor, particularly those that overlap with aggregations of

  5. Evaluation of habitat suitability index models by global sensitivity and uncertainty analyses: a case study for submerged aquatic vegetation

    USGS Publications Warehouse

    Zajac, Zuzanna; Stith, Bradley M.; Bowling, Andrea C.; Langtimm, Catherine A.; Swain, Eric D.

    2015-01-01

    Habitat suitability index (HSI) models are commonly used to predict habitat quality and species distributions and are used to develop biological surveys, assess reserve and management priorities, and anticipate possible change under different management or climate change scenarios. Important management decisions may be based on model results, often without a clear understanding of the level of uncertainty associated with model outputs. We present an integrated methodology to assess the propagation of uncertainty from both inputs and structure of the HSI models on model outputs (uncertainty analysis: UA) and relative importance of uncertain model inputs and their interactions on the model output uncertainty (global sensitivity analysis: GSA). We illustrate the GSA/UA framework using simulated hydrology input data from a hydrodynamic model representing sea level changes and HSI models for two species of submerged aquatic vegetation (SAV) in southwest Everglades National Park: Vallisneria americana (tape grass) and Halodule wrightii (shoal grass). We found considerable spatial variation in uncertainty for both species, but distributions of HSI scores still allowed discrimination of sites with good versus poor conditions. Ranking of input parameter sensitivities also varied spatially for both species, with high habitat quality sites showing higher sensitivity to different parameters than low-quality sites. HSI models may be especially useful when species distribution data are unavailable, providing means of exploiting widely available environmental datasets to model past, current, and future habitat conditions. The GSA/UA approach provides a general method for better understanding HSI model dynamics, the spatial and temporal variation in uncertainties, and the parameters that contribute most to model uncertainty. Including an uncertainty and sensitivity analysis in modeling efforts as part of the decision-making framework will result in better-informed, more robust

  6. Evaluation of habitat suitability index models by global sensitivity and uncertainty analyses: a case study for submerged aquatic vegetation

    PubMed Central

    Zajac, Zuzanna; Stith, Bradley; Bowling, Andrea C; Langtimm, Catherine A; Swain, Eric D

    2015-01-01

    Habitat suitability index (HSI) models are commonly used to predict habitat quality and species distributions and are used to develop biological surveys, assess reserve and management priorities, and anticipate possible change under different management or climate change scenarios. Important management decisions may be based on model results, often without a clear understanding of the level of uncertainty associated with model outputs. We present an integrated methodology to assess the propagation of uncertainty from both inputs and structure of the HSI models on model outputs (uncertainty analysis: UA) and relative importance of uncertain model inputs and their interactions on the model output uncertainty (global sensitivity analysis: GSA). We illustrate the GSA/UA framework using simulated hydrology input data from a hydrodynamic model representing sea level changes and HSI models for two species of submerged aquatic vegetation (SAV) in southwest Everglades National Park: Vallisneria americana (tape grass) and Halodule wrightii (shoal grass). We found considerable spatial variation in uncertainty for both species, but distributions of HSI scores still allowed discrimination of sites with good versus poor conditions. Ranking of input parameter sensitivities also varied spatially for both species, with high habitat quality sites showing higher sensitivity to different parameters than low-quality sites. HSI models may be especially useful when species distribution data are unavailable, providing means of exploiting widely available environmental datasets to model past, current, and future habitat conditions. The GSA/UA approach provides a general method for better understanding HSI model dynamics, the spatial and temporal variation in uncertainties, and the parameters that contribute most to model uncertainty. Including an uncertainty and sensitivity analysis in modeling efforts as part of the decision-making framework will result in better-informed, more robust

  7. Evaluation of habitat suitability index models by global sensitivity and uncertainty analyses: a case study for submerged aquatic vegetation.

    PubMed

    Zajac, Zuzanna; Stith, Bradley; Bowling, Andrea C; Langtimm, Catherine A; Swain, Eric D

    2015-07-01

    Habitat suitability index (HSI) models are commonly used to predict habitat quality and species distributions and are used to develop biological surveys, assess reserve and management priorities, and anticipate possible change under different management or climate change scenarios. Important management decisions may be based on model results, often without a clear understanding of the level of uncertainty associated with model outputs. We present an integrated methodology to assess the propagation of uncertainty from both inputs and structure of the HSI models on model outputs (uncertainty analysis: UA) and relative importance of uncertain model inputs and their interactions on the model output uncertainty (global sensitivity analysis: GSA). We illustrate the GSA/UA framework using simulated hydrology input data from a hydrodynamic model representing sea level changes and HSI models for two species of submerged aquatic vegetation (SAV) in southwest Everglades National Park: Vallisneria americana (tape grass) and Halodule wrightii (shoal grass). We found considerable spatial variation in uncertainty for both species, but distributions of HSI scores still allowed discrimination of sites with good versus poor conditions. Ranking of input parameter sensitivities also varied spatially for both species, with high habitat quality sites showing higher sensitivity to different parameters than low-quality sites. HSI models may be especially useful when species distribution data are unavailable, providing means of exploiting widely available environmental datasets to model past, current, and future habitat conditions. The GSA/UA approach provides a general method for better understanding HSI model dynamics, the spatial and temporal variation in uncertainties, and the parameters that contribute most to model uncertainty. Including an uncertainty and sensitivity analysis in modeling efforts as part of the decision-making framework will result in better-informed, more robust

  8. Challenges of predicting the potential distribution of a slow-spreading invader: a habitat suitability map for an invasive riparian tree

    USGS Publications Warehouse

    Jarnevich, Catherine S.; Reynolds, Lindsay V.

    2011-01-01

    Understanding the potential spread of invasive species is essential for land managers to prevent their establishment and restore impacted habitat. Habitat suitability modeling provides a tool for researchers and managers to understand the potential extent of invasive species spread. Our goal was to use habitat suitability modeling to map potential habitat of the riparian plant invader, Russian olive (Elaeagnus angustifolia). Russian olive has invaded riparian habitat across North America and is continuing to expand its range. We compiled 11 disparate datasets for Russian olive presence locations (n = 1,051 points and 139 polygons) in the western US and used Maximum entropy (Maxent) modeling to develop two habitat suitability maps for Russian olive in the western United States: one with coarse-scale water data and one with fine-scale water data. Our models were able to accurately predict current suitable Russian olive habitat (Coarse model: training AUC = 0.938, test AUC = 0.907; Fine model: training AUC = 0.923, test AUC = 0.885). Distance to water was the most important predictor for Russian olive presence in our coarse-scale water model, but it was only the fifth most important variable in the fine-scale model, suggesting that when water bodies are considered on a fine scale, Russian olive does not necessarily rely on water. Our model predicted that Russian olive has suitable habitat further west from its current distribution, expanding into the west coast and central North America. Our methodology proves useful for identifying potential future areas of invasion. Model results may be influenced by locations of cultivated individuals and sampling bias. Further study is needed to examine the potential for Russian olive to invade beyond its current range. Habitat suitability modeling provides an essential tool for enhancing our understanding of invasive species spread.

  9. Modelization of the Current and Future Habitat Suitability of Rhododendron ferrugineum Using Potential Snow Accumulation.

    PubMed

    Komac, Benjamin; Esteban, Pere; Trapero, Laura; Caritg, Roger

    2016-01-01

    Mountain areas are particularly sensitive to climate change. Species distribution models predict important extinctions in these areas whose magnitude will depend on a number of different factors. Here we examine the possible impact of climate change on the Rhododendron ferrugineum (alpenrose) niche in Andorra (Pyrenees). This species currently occupies 14.6 km2 of this country and relies on the protection afforded by snow cover in winter. We used high-resolution climatic data, potential snow accumulation and a combined forecasting method to obtain the realized niche model of this species. Subsequently, we used data from the high-resolution Scampei project climate change projection for the A2, A1B and B1 scenarios to model its future realized niche model. The modelization performed well when predicting the species's distribution, which improved when we considered the potential snow accumulation, the most important variable influencing its distribution. We thus obtained a potential extent of about 70.7 km(2) or 15.1% of the country. We observed an elevation lag distribution between the current and potential distribution of the species, probably due to its slow colonization rate and the small-scale survey of seedlings. Under the three climatic scenarios, the realized niche model of the species will be reduced by 37.9-70.1 km(2) by the end of the century and it will become confined to what are today screes and rocky hillside habitats. The particular effects of climate change on seedling establishment, as well as on the species' plasticity and sensitivity in the event of a reduction of the snow cover, could worsen these predictions. PMID:26824847

  10. Modelization of the Current and Future Habitat Suitability of Rhododendron ferrugineum Using Potential Snow Accumulation

    PubMed Central

    Komac, Benjamin; Esteban, Pere; Trapero, Laura; Caritg, Roger

    2016-01-01

    Mountain areas are particularly sensitive to climate change. Species distribution models predict important extinctions in these areas whose magnitude will depend on a number of different factors. Here we examine the possible impact of climate change on the Rhododendron ferrugineum (alpenrose) niche in Andorra (Pyrenees). This species currently occupies 14.6 km2 of this country and relies on the protection afforded by snow cover in winter. We used high-resolution climatic data, potential snow accumulation and a combined forecasting method to obtain the realized niche model of this species. Subsequently, we used data from the high-resolution Scampei project climate change projection for the A2, A1B and B1 scenarios to model its future realized niche model. The modelization performed well when predicting the species’s distribution, which improved when we considered the potential snow accumulation, the most important variable influencing its distribution. We thus obtained a potential extent of about 70.7 km2 or 15.1% of the country. We observed an elevation lag distribution between the current and potential distribution of the species, probably due to its slow colonization rate and the small-scale survey of seedlings. Under the three climatic scenarios, the realized niche model of the species will be reduced by 37.9–70.1 km2 by the end of the century and it will become confined to what are today screes and rocky hillside habitats. The particular effects of climate change on seedling establishment, as well as on the species’ plasticity and sensitivity in the event of a reduction of the snow cover, could worsen these predictions. PMID:26824847

  11. Estimating relative risk of within-lake aquatic plant invasion using combined measures of recreational boater movement and habitat suitability

    PubMed Central

    Kendall, Bruce E.; Jerde, Christopher L.; Anderson, Lars W.J.

    2015-01-01

    Effective monitoring, prevention and impact mitigation of nonindigenous aquatic species relies upon the ability to predict dispersal pathways and receiving habitats with the greatest risk of establishment. To examine mechanisms affecting species establishment within a large lake, we combined observations of recreational boater movements with empirical measurements of habitat suitability represented by nearshore wave energy to assess the relative risk of Eurasian watermilfoil (Myriophyllum spicatum) establishment. The model was evaluated using information from a 17 year (1995–2012) sequence of M. spicatum presence and absence monitoring. M. spicatum presence was not specifically correlated with recreational boater movements; however its establishment appears to be limited by wave action in Lake Tahoe. Of the sites in the “High” establishment risk category (n = 37), 54% had current or historical infestations, which included 8 of the 10 sites with the highest relative risk. Of the 11 sites in the “Medium” establishment risk category, 5 had current or historical M. spicatum populations. Most (76%) of the sites in the “Low” establishment risk category were observed in locations with higher wave action. Four sites that received zero boater visits from infested locations were occupied by M. spicatum. This suggests that the boater survey either represents incomplete coverage of boater movement, or other processes, such as the movement of propagules by surface currents or introductions from external sources are important to the establishment of this species. This study showed the combination of habitat specific and dispersal data in a relative risk framework can potentially reduce uncertainty in estimates of invasion risk. PMID:25802813

  12. Limacina helicina shell dissolution as an indicator of declining habitat suitability owing to ocean acidification in the California Current Ecosystem

    PubMed Central

    Bednaršek, N.; Feely, R. A.; Reum, J. C. P.; Peterson, B.; Menkel, J.; Alin, S. R.; Hales, B.

    2014-01-01

    Few studies to date have demonstrated widespread biological impacts of ocean acidification (OA) under conditions currently found in the natural environment. From a combined survey of physical and chemical water properties and biological sampling along the Washington–Oregon–California coast in August 2011, we show that large portions of the shelf waters are corrosive to pteropods in the natural environment. We show a strong positive correlation between the proportion of pteropod individuals with severe shell dissolution damage and the percentage of undersaturated water in the top 100 m with respect to aragonite. We found 53% of onshore individuals and 24% of offshore individuals on average to have severe dissolution damage. Relative to pre-industrial CO2 concentrations, the extent of undersaturated waters in the top 100 m of the water column has increased over sixfold along the California Current Ecosystem (CCE). We estimate that the incidence of severe pteropod shell dissolution owing to anthropogenic OA has doubled in near shore habitats since pre-industrial conditions across this region and is on track to triple by 2050. These results demonstrate that habitat suitability for pteropods in the coastal CCE is declining. The observed impacts represent a baseline for future observations towards understanding broader scale OA effects. PMID:24789895

  13. Fragmentation analysis for prediction of suitable habitat for vectors: example of riverine tsetse flies in Burkina Faso.

    PubMed

    Guerrini, L; Bord, J P; Ducheyne, E; Bouyer, J

    2008-11-01

    Tsetse flies are the cyclic vectors of sleeping sickness and African animal trypanosomosis. The possibility to classify the natural habitat of riverine tsetse species is explored in the Mouhoun River basin, Burkina Faso: the objectives were to discriminate the riverine forests community types and their fragmentation levels by using Landsat 7 enhanced thematic mapper images, to map tsetse densities. Glossina palpalis gambiensis Vanderplank 1949 (Diptera: Glossinidae) and G. tachinoides Westwood, 1850 are the vectors of trypanosomoses in this area. After a supervised classification, the community types were discriminated using the water area in 400-m-wide polygons around the river. A fragmentation analysis of the swamp forest unit, cross-tabulated with the community types, lead to identification of the final landscapes where tsetse apparent densities (ADT) were implemented using a training data set of 608 trap locations. The predicted ADT were then compared with an independent validation data set of 78 trap locations. The correlation between the model predictions and the validation data set was high, validating this approach (P < 0.001). The riverine forest community type and fragmentation level are critical factors for riverine tsetse species, which should be taken into consideration to map their suitable habitat. PMID:19058646

  14. Back to the future: using historical climate variation to project near-term shifts in habitat suitable for coast redwood.

    PubMed

    Fernández, Miguel; Hamilton, Healy H; Kueppers, Lara M

    2015-11-01

    Studies that model the effect of climate change on terrestrial ecosystems often use climate projections from downscaled global climate models (GCMs). These simulations are generally too coarse to capture patterns of fine-scale climate variation, such as the sharp coastal energy and moisture gradients associated with wind-driven upwelling of cold water. Coastal upwelling may limit future increases in coastal temperatures, compromising GCMs' ability to provide realistic scenarios of future climate in these coastal ecosystems. Taking advantage of naturally occurring variability in the high-resolution historic climatic record, we developed multiple fine-scale scenarios of California climate that maintain coherent relationships between regional climate and coastal upwelling. We compared these scenarios against coarse resolution GCM projections at a regional scale to evaluate their temporal equivalency. We used these historically based scenarios to estimate potential suitable habitat for coast redwood (Sequoia sempervirens D. Don) under 'normal' combinations of temperature and precipitation, and under anomalous combinations representative of potential future climates. We found that a scenario of warmer temperature with historically normal precipitation is equivalent to climate projected by GCMs for California by 2020-2030 and that under these conditions, climatically suitable habitat for coast redwood significantly contracts at the southern end of its current range. Our results suggest that historical climate data provide a high-resolution alternative to downscaled GCM outputs for near-term ecological forecasts. This method may be particularly useful in other regions where local climate is strongly influenced by ocean-atmosphere dynamics that are not represented by coarse-scale GCMs. PMID:26149607

  15. Modeling a habitat suitability index for the eastern fall cohort of Ommastrephes bartramii in the central North Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Chen, Xinjun; Tian, Siquan; Liu, Bilin; Chen, Yong

    2011-05-01

    The eastern fall cohort of the neon flying squid, Ommastrephes bartramii, has been commercially exploited by the Chinese squid jigging fleet in the central North Pacific Ocean since the late 1990s. To understand and identify their optimal habitat, we have developed a habitat suitability index (HSI) model using two potential important environmental variables — sea surface temperature (SST) and sea surface height anomaly (SSHA) — and fishery data from the main fishing ground (165°-180°E) during June and July of 1999-2003. A geometric mean model (GMM), minimum model (MM) and arithmetic weighted model (AWM) with different weights were compared and the best HSI model was selected using Akaike's information criterion (AIC). The performance of the developed HSI model was evaluated using fishery data for 2004. This study suggests that the highest catch per unit effort (CPUE) and fishing effort are closely related to SST and SSHA. The best SST- and SSHA-based suitability index (SI) regression models were SISST-based = 0.7SIeffort-SST + 0.3 SICPUE-SST, and SISSHA-based = 0.5SIeffort-SSHA + 0.5SICPUE-SSHA, respectively, showing that fishing effort is more important than CPUE in the estimation of SI. The best HSI model was the AWM, defined as HSI=0.3SISST-based+ 0.7SISSHA-based, indicating that SSHA is more important than SST in estimating the HSI of squid. In 2004, monthly HSI values greater than 0.6 coincided with the distribution of productive fishing ground and high CPUE in June and July, suggesting that the models perform well. The proposed model provides an important tool in our efforts to develop forecasting capacity of squid spatial dynamics.

  16. Habitat suitability for juvenile common sole ( Solea solea, L.) in the Bay of Biscay (France): A quantitative description using indicators based on epibenthic fauna

    NASA Astrophysics Data System (ADS)

    Le Pape, Olivier; Baulier, Loîc; Cloarec, Aurélie; Martin, Jocelyne; Le Loc'h, François; Désaunay, Yves

    2007-02-01

    This study describes the spatial distribution of young-of-the-year common sole based on beam trawl surveys conducted in late summer in the coastal and estuarine parts of the Bay of Biscay (France). Previous studies showed that habitat suitability for juvenile common sole varies according to physical factors and notably bathymetry and sediment structure. Nevertheless, the use of these descriptors alone to model habitat suitability led to considerable unexplained variability in juvenile common sole distribution. Hence, the epibenthic macro- and megafauna collected during beam trawl surveys was taken into account to improve models of habitat suitability for these juvenile flatfish. Ecotrophic guilds based on life traits (behaviour, mobility and feeding) were used to develop generic indicators of trawled benthic fauna. These synthetic descriptors were used in generalized linear models of habitat suitability in order to characterize the distribution of juvenile common sole. This approach significantly improved the description based on physical descriptors and allowed demonstrating that young common sole distribution is related to the density of trawled deposit and suspension feeders and also of carnivorous organisms. These models provide a reliable method to develop indicators of nursery habitat suitability from trawl survey data with the aim of assessing and surveying their quality.

  17. Assesment of future river habitat suitability under climate change scenarios in a mesoscale Alpine watershed of Italy (Serio River, Italian Alps)

    NASA Astrophysics Data System (ADS)

    Groppelli, B.; Confortola, G.; Soncini, A.; Bocchiola, D.; Rosso, R.

    2011-12-01

    We merge hydraulic river modelling, use of suitability functions for fish guild colonization and hydrological modelling of catchment response to investigate future (until 2100) hydrological cycle and fish habitat suitability for an Alpine catchment in Italy, Serio river (drainage area 450 Km2, average altitude 1300 m a.s.l., main channel length ca. 36 km). Based upon detailed river channel morphology data for 73 river sections and direct local investigation we then set up and tune a quasi 2-D (i.e. with floodplains) hydraulic model for in channel flows hydraulics, depending upon daily in stream discharge. We then evaluate distributed values of hydraulic variables and therein composite habitat suitability indexes CS for a representative target species (brown trout, Salmo Trutta Fario L.), resulting into usable wetted area WUA for fish colonization. We consider both juvenile JUV and adults AD, and we evaluate the frequency (days in a year/season) of yearly/seasonal, spatially distributed and bulk (whole stream) habitat quality. We then provide synthetic indicators of (yearly/seasonal) suitability level and duration within the river. We then set up a minimal (T, P), properly tuned hydrological model able to mimick Serio river's hydrological cycle. We then use downscaled future precipitation and temperature from three general circulation models, GCMs (PCM, CCSM3, and HadCM3) available within the IPCC's data base chosen for the purpose based upon previous studies, to feed our hydrological model and provide projected hydrological regime of the catchment, together with modified habitat suitability. We then comment upon modified flow regime, habitat suitability as obtained and related uncertainty. The proposed results may be of use for river managers and may provide a template for investigation about future river habitat quality pending climate change.

  18. Spatial transferability of habitat suitability models of Nephrops norvegicus among fished areas in the Northeast Atlantic: sufficiently stable for marine resource conservation?

    PubMed

    Lauria, Valentina; Power, Anne Marie; Lordan, Colm; Weetman, Adrian; Johnson, Mark P

    2015-01-01

    Knowledge of the spatial distribution and habitat associations of species in relation to the environment is essential for their management and conservation. Habitat suitability models are useful in quantifying species-environment relationships and predicting species distribution patterns. Little is known, however, about the stability and performance of habitat suitability models when projected into new areas (spatial transferability) and how this can inform resource management. The aims of this study were to model habitat suitability of Norway lobster (Nephrops norvegicus) in five fished areas of the Northeast Atlantic (Aran ground, Irish Sea, Celtic Sea, Scotland Inshore and Fladen ground), and to test for spatial transferability of habitat models among multiple regions. Nephrops burrow density was modelled using generalised additive models (GAMs) with predictors selected from four environmental variables (depth, slope, sediment and rugosity). Models were evaluated and tested for spatial transferability among areas. The optimum models (lowest AICc) for different areas always included depth and sediment as predictors. Burrow densities were generally greater at depth and in finer sediments, but relationships for individual areas were sometimes more complex. Aside from an inclusion of depth and sediment, the optimum models differed between fished areas. When it came to tests of spatial transferability, however, most of the models were able to predict Nephrops density in other areas. Furthermore, transferability was not dependent on use of the optimum models since competing models were also able to achieve a similar level of transferability to new areas. A degree of decoupling between model 'fitting' performance and spatial transferability supports the use of simpler models when extrapolating habitat suitability maps to different areas. Differences in the form and performance of models from different areas may supply further information on the processes shaping

  19. Spatial Transferability of Habitat Suitability Models of Nephrops norvegicus among Fished Areas in the Northeast Atlantic: Sufficiently Stable for Marine Resource Conservation?

    PubMed Central

    Lauria, Valentina; Power, Anne Marie; Lordan, Colm; Weetman, Adrian; Johnson, Mark P.

    2015-01-01

    Knowledge of the spatial distribution and habitat associations of species in relation to the environment is essential for their management and conservation. Habitat suitability models are useful in quantifying species-environment relationships and predicting species distribution patterns. Little is known, however, about the stability and performance of habitat suitability models when projected into new areas (spatial transferability) and how this can inform resource management. The aims of this study were to model habitat suitability of Norway lobster (Nephrops norvegicus) in five fished areas of the Northeast Atlantic (Aran ground, Irish Sea, Celtic Sea, Scotland Inshore and Fladen ground), and to test for spatial transferability of habitat models among multiple regions. Nephrops burrow density was modelled using generalised additive models (GAMs) with predictors selected from four environmental variables (depth, slope, sediment and rugosity). Models were evaluated and tested for spatial transferability among areas. The optimum models (lowest AICc) for different areas always included depth and sediment as predictors. Burrow densities were generally greater at depth and in finer sediments, but relationships for individual areas were sometimes more complex. Aside from an inclusion of depth and sediment, the optimum models differed between fished areas. When it came to tests of spatial transferability, however, most of the models were able to predict Nephrops density in other areas. Furthermore, transferability was not dependent on use of the optimum models since competing models were also able to achieve a similar level of transferability to new areas. A degree of decoupling between model ‘fitting’ performance and spatial transferability supports the use of simpler models when extrapolating habitat suitability maps to different areas. Differences in the form and performance of models from different areas may supply further information on the processes shaping

  20. Geographical distribution patterns and habitat suitability models for presence of host-seeking ixodid ticks in dense woodlands of Mendocino County, California.

    PubMed

    Eisen, L; Eisen, R J; Lane, R S

    2006-03-01

    We used drag sampling to examine the geographical distribution patterns of ixodid ticks engaging in open (non-nidicolous) host-seeking behavior in dense woodland habitats of the climatically and ecologically diverse Mendocino County in north coastal California. The findings based on this sampling methodology reflect risk of human exposure to host-seeking ticks rather than the true distribution of the ticks. Drag sampling in 78 sites yielded 7,860 nymphal or adult Ixodes pacificus Cooley & Kohls, 220 Dermacentor occidentalis Marx, 150 Ixodes spinipalpis Hadwen & Nuttall, 15 Hemaphysalis leporispalustris (Packard), 12 Ixodes angustus Neumann, 12 Ixodes auritulus Neumann, and a single Dermacentor variabilis (Say). I. pacificus, which is the primary vector of the Lyme disease spirochete Borrelia burgdorferi to humans in California, occurred in all 78 sites examined. D. occidentalis, another tick species commonly biting humans in California, and H. leporispalustris typically were encountered in oak-associated woodlands in the central or eastern parts of the county. In contrast, three species of Ixodes ticks (I. angustus, I. auritulus, and I. spinipalpis) most commonly were found questing openly in woodlands with redwood present in the western part of the county. I. angustus and I. spinipalpis are occasional human biters and known experimental vectors of B. burgdorferi. Our study represents the first collection of large numbers of openly host-seeking I. spinipalpis ticks. Univariate tests of associations between presence of ticks (D. occidentalis, H. leporispalustris, I. angustus, I. auritulus, or I. spinipalpis) and environmental geographical information systems-remote sensing (GIS/ RS)-based data indicated that elevation, number of growing degree-days, and tasseled cap brightness, greenness, and wetness are especially useful predictors of presence of openly hostseeking ticks. Combinations of the above-mentioned GIS/RS-based data yielded significant logistic regression

  1. High-resolution assessment of land use impacts on biodiversity in life cycle assessment using species habitat suitability models.

    PubMed

    de Baan, Laura; Curran, Michael; Rondinini, Carlo; Visconti, Piero; Hellweg, Stefanie; Koellner, Thomas

    2015-02-17

    Agricultural land use is a main driver of global biodiversity loss. The assessment of land use impacts in decision-support tools such as life cycle assessment (LCA) requires spatially explicit models, but existing approaches are either not spatially differentiated or modeled at very coarse scales (e.g., biomes or ecoregions). In this paper, we develop a high-resolution (900 m) assessment method for land use impacts on biodiversity based on habitat suitability models (HSM) of mammal species. This method considers potential land use effects on individual species, and impacts are weighted by the species' conservation status and global rarity. We illustrate the method using a case study of crop production in East Africa, but the underlying HSMs developed by the Global Mammals Assessment are available globally. We calculate impacts of three major export crops and compare the results to two previously developed methods (focusing on local and regional impacts, respectively) to assess the relevance of the methodological innovations proposed in this paper. The results highlight hotspots of product-related biodiversity impacts that help characterize the links among agricultural production, consumption, and biodiversity loss. PMID:25584628

  2. Habitat suitability modelling reveals a strong niche overlap between two poorly known species, the broom hare and the Pyrenean grey partridge, in the north of Spain

    NASA Astrophysics Data System (ADS)

    Acevedo, Pelayo; Alzaga, Vanesa; Cassinello, Jorge; Gortázar, Christian

    2007-03-01

    In the present work, we derive a habitat suitability model of the broom hare and the Pyrenean grey partridge in the Cantabrian Mountains by using the Ecological Niche Factor Analysis. Both species are endemic to the northern of Iberian mountains, and because of the vulnerability of the hare to endangerment or extinction and because of the great interest in the partridge, this habitat requires specific conservation measures. Literature on these animals' biology and ecology is practically nonexistent. Habitat suitability analyses show that the hare and partridge occupy very similar ecological niches, characterized by a high percentage of broom and heather scrublands, high altitude and slope, and limited human accessibility. We have identified differences in habitat selection between the Pyrenean grey partridge and other subspecies of partridge present in central-northern Europe. Our results indicate a probable metapopulation structure for both the hare and partridge; however, according to our predictive maps, there is a high connectivity between suitable habitats. Current decline of traditional rural activities, such as mountain livestock, are affecting the mosaic landscape. This, in turn, enhances biodiversity in the area and, particularly, the viability of these valuable animal populations.

  3. Variability of Suitable Habitat of Western Winter-Spring Cohort for Neon Flying Squid in the Northwest Pacific under Anomalous Environments

    PubMed Central

    Yu, Wei; Chen, Xinjun; Yi, Qian; Chen, Yong; Zhang, Yang

    2015-01-01

    We developed a habitat suitability index (HSI) model to evaluate the variability of suitable habitat for neon flying squid (Ommastrephes bartramii) under anomalous environments in the Northwest Pacific Ocean. Commercial fisheries data from the Chinese squid-jigging vessels on the traditional fishing ground bounded by 35°-45°N and 150°-175°E from July to November during 1998-2009 were used for analyses, as well as the environmental variables including sea surface temperature (SST), chlorophyll-a (Chl-a) concentration, sea surface height anomaly (SSHA) and sea surface salinity (SSS). Two empirical HSI models (arithmetic mean model, AMM; geometric mean model, GMM) were established according to the frequency distribution of fishing efforts. The AMM model was found to perform better than the GMM model. The AMM-based HSI model was further validated by the fishery and environmental data in 2010. The predicted HSI values in 1998 (high catch), 2008 (average catch) and 2009 (low catch) indicated that the squid habitat quality was strongly associated with the ENSO-induced variability in the oceanic conditions on the fishing ground. The La Niña events in 1998 tended to yield warm SST and favorable range of Chl-a concentration and SSHA, resulting in high-quality habitats for O. bartramii. While the fishing ground in the El Niño year of 2009 experienced anomalous cool waters and unfavorable range of Chl-a concentration and SSHA, leading to relatively low-quality squid habitats. Our findings suggest that the La Niña event in 1998 tended to result in more favorable habitats for O. bartramii in the Northwest Pacific with the gravity centers of fishing efforts falling within the defined suitable habitat and yielding high squid catch; whereas the El Niño event in 2009 yielded less favorable habitat areas with the fishing effort distribution mismatching the suitable habitat and a dramatic decline of the catch of O. bartramii. This study might provide some potentially valuable

  4. Variability of Suitable Habitat of Western Winter-Spring Cohort for Neon Flying Squid in the Northwest Pacific under Anomalous Environments.

    PubMed

    Yu, Wei; Chen, Xinjun; Yi, Qian; Chen, Yong; Zhang, Yang

    2015-01-01

    We developed a habitat suitability index (HSI) model to evaluate the variability of suitable habitat for neon flying squid (Ommastrephes bartramii) under anomalous environments in the Northwest Pacific Ocean. Commercial fisheries data from the Chinese squid-jigging vessels on the traditional fishing ground bounded by 35°-45°N and 150°-175°E from July to November during 1998-2009 were used for analyses, as well as the environmental variables including sea surface temperature (SST), chlorophyll-a (Chl-a) concentration, sea surface height anomaly (SSHA) and sea surface salinity (SSS). Two empirical HSI models (arithmetic mean model, AMM; geometric mean model, GMM) were established according to the frequency distribution of fishing efforts. The AMM model was found to perform better than the GMM model. The AMM-based HSI model was further validated by the fishery and environmental data in 2010. The predicted HSI values in 1998 (high catch), 2008 (average catch) and 2009 (low catch) indicated that the squid habitat quality was strongly associated with the ENSO-induced variability in the oceanic conditions on the fishing ground. The La Niña events in 1998 tended to yield warm SST and favorable range of Chl-a concentration and SSHA, resulting in high-quality habitats for O. bartramii. While the fishing ground in the El Niño year of 2009 experienced anomalous cool waters and unfavorable range of Chl-a concentration and SSHA, leading to relatively low-quality squid habitats. Our findings suggest that the La Niña event in 1998 tended to result in more favorable habitats for O. bartramii in the Northwest Pacific with the gravity centers of fishing efforts falling within the defined suitable habitat and yielding high squid catch; whereas the El Niño event in 2009 yielded less favorable habitat areas with the fishing effort distribution mismatching the suitable habitat and a dramatic decline of the catch of O. bartramii. This study might provide some potentially valuable

  5. Development and validation of a habitat suitability model for the non-indigenous seagrass Zostera japonica in North AmericaOF THE INTRODUCED SEAGRASS ZOSTERA JAPONICA

    EPA Science Inventory

    We developed a spatially-explicit, flexible 3-parameter habitat suitability model that can be used to identify and predict areas at higher risk for non-native dwarf eelgrass (Zostera japonica) invasion. The model uses simple environmental parameters (depth, nearshore slope, and s...

  6. Assessment of Chinese sturgeon habitat suitability in the Yangtze River (China): Comparison of generalized additive model, data-driven fuzzy logic model, and preference curve model

    NASA Astrophysics Data System (ADS)

    Yi, Yujun; Sun, Jie; Zhang, Shanghong; Yang, Zhifeng

    2016-05-01

    To date, a wide range of models have been applied to evaluate aquatic habitat suitability. In this study, three models, including the expert knowledge-based preference curve model (PCM), data-driven fuzzy logic model (DDFL), and generalized additive model (GAM), are used on a common data set to compare their effectiveness and accuracy. The true skill statistic (TSS) and the area under the receiver operating characteristics curve (AUC) are used to evaluate the accuracy of the three models. The results indicate that the two data-based methods (DDFL and GAM) yield better accuracy than the expert knowledge-based PCM, and the GAM yields the best accuracy. There are minor differences in the suitable ranges of the physical habitat variables obtained from the three models. The hydraulic habitat suitability index (HHSI) calculated by the PCM is the largest, followed by the DDFL and then the GAM. The results illustrate that data-based models can describe habitat suitability more objectively and accurately when there are sufficient data. When field data are lacking, combining expertise with data-based models is recommended. When field data are difficult to obtain, an expert knowledge-based model can be used as a replacement for the data-based methods.

  7. Silvicolous on a small scale: possibilities and limitations of habitat suitability models for small, elusive mammals in conservation management and landscape planning.

    PubMed

    Becker, Nina I; Encarnação, Jorge A

    2015-01-01

    Species distribution and endangerment can be assessed by habitat-suitability modelling. This study addresses methodical aspects of habitat suitability modelling and includes an application example in actual species conservation and landscape planning. Models using species presence-absence data are preferable to presence-only models. In contrast to species presence data, absences are rarely recorded. Therefore, many studies generate pseudo-absence data for modelling. However, in this study model quality was higher with null samples collected in the field. Next to species data the choice of landscape data is crucial for suitability modelling. Landscape data with high resolution and ecological relevance for the study species improve model reliability and quality for small elusive mammals like Muscardinus avellanarius. For large scale assessment of species distribution, models with low-detailed data are sufficient. For regional site-specific conservation issues like a conflict-free site for new wind turbines, high-detailed regional models are needed. Even though the overlap with optimally suitable habitat for M. avellanarius was low, the installation of wind plants can pose a threat due to habitat loss and fragmentation. To conclude, modellers should clearly state the purpose of their models and choose the according level of detail for species and environmental data. PMID:25781894

  8. ESTIMATING THE AREAL EXTENT OF SUITABLE HABITAT FOR POST-LARVAL AND JUVENILE BROWN SHRIMP (FARFANTEPENAEUS AZTECUS) IN MOBILE BAY NATIONAL ESTUARY II

    EPA Science Inventory

    Extensive research has demonstrated a strong correlation between wetlands and productivity of shrimp fisheries in the Gulf of Mexico. Unfortunately, the Gulf coast has the highest rate of wetland loss in the U.S. Quantifying suitable habitat for post-larval and juvenile shrimp ...

  9. Silvicolous on a Small Scale: Possibilities and Limitations of Habitat Suitability Models for Small, Elusive Mammals in Conservation Management and Landscape Planning

    PubMed Central

    2015-01-01

    Species distribution and endangerment can be assessed by habitat-suitability modelling. This study addresses methodical aspects of habitat suitability modelling and includes an application example in actual species conservation and landscape planning. Models using species presence-absence data are preferable to presence-only models. In contrast to species presence data, absences are rarely recorded. Therefore, many studies generate pseudo-absence data for modelling. However, in this study model quality was higher with null samples collected in the field. Next to species data the choice of landscape data is crucial for suitability modelling. Landscape data with high resolution and ecological relevance for the study species improve model reliability and quality for small elusive mammals like Muscardinus avellanarius. For large scale assessment of species distribution, models with low-detailed data are sufficient. For regional site-specific conservation issues like a conflict-free site for new wind turbines, high-detailed regional models are needed. Even though the overlap with optimally suitable habitat for M. avellanarius was low, the installation of wind plants can pose a threat due to habitat loss and fragmentation. To conclude, modellers should clearly state the purpose of their models and choose the according level of detail for species and environmental data. PMID:25781894

  10. Downscaling Pest Risk Analyses: Identifying Current and Future Potentially Suitable Habitats for Parthenium hysterophorus with Particular Reference to Europe and North Africa.

    PubMed

    Kriticos, Darren J; Brunel, Sarah; Ota, Noboru; Fried, Guillaume; Oude Lansink, Alfons G J M; Panetta, F Dane; Prasad, T V Ramachandra; Shabbir, Asad; Yaacoby, Tuvia

    2015-01-01

    Pest Risk Assessments (PRAs) routinely employ climatic niche models to identify endangered areas. Typically, these models consider only climatic factors, ignoring the 'Swiss Cheese' nature of species ranges due to the interplay of climatic and habitat factors. As part of a PRA conducted for the European and Mediterranean Plant Protection Organization, we developed a climatic niche model for Parthenium hysterophorus, explicitly including the effects of irrigation where it was known to be practiced. We then downscaled the climatic risk model using two different methods to identify the suitable habitat types: expert opinion (following the EPPO PRA guidelines) and inferred from the global spatial distribution. The PRA revealed a substantial risk to the EPPO region and Central and Western Africa, highlighting the desirability of avoiding an invasion by P. hysterophorus. We also consider the effects of climate change on the modelled risks. The climate change scenario indicated the risk of substantial further spread of P. hysterophorus in temperate northern hemisphere regions (North America, Europe and the northern Middle East), and also high elevation equatorial regions (Western Brazil, Central Africa, and South East Asia) if minimum temperatures increase substantially. Downscaling the climate model using habitat factors resulted in substantial (approximately 22-53%) reductions in the areas estimated to be endangered. Applying expert assessments as to suitable habitat classes resulted in the greatest reduction in the estimated endangered area, whereas inferring suitable habitats factors from distribution data identified more land use classes and a larger endangered area. Despite some scaling issues with using a globally conformal Land Use Systems dataset, the inferential downscaling method shows promise as a routine addition to the PRA toolkit, as either a direct model component, or simply as a means of better informing an expert assessment of the suitable habitat types

  11. Downscaling Pest Risk Analyses: Identifying Current and Future Potentially Suitable Habitats for Parthenium hysterophorus with Particular Reference to Europe and North Africa

    PubMed Central

    Kriticos, Darren J.; Brunel, Sarah; Ota, Noboru; Fried, Guillaume; Oude Lansink, Alfons G. J. M.; Panetta, F. Dane; Prasad, T. V. Ramachandra; Shabbir, Asad; Yaacoby, Tuvia

    2015-01-01

    Pest Risk Assessments (PRAs) routinely employ climatic niche models to identify endangered areas. Typically, these models consider only climatic factors, ignoring the ‘Swiss Cheese’ nature of species ranges due to the interplay of climatic and habitat factors. As part of a PRA conducted for the European and Mediterranean Plant Protection Organization, we developed a climatic niche model for Parthenium hysterophorus, explicitly including the effects of irrigation where it was known to be practiced. We then downscaled the climatic risk model using two different methods to identify the suitable habitat types: expert opinion (following the EPPO PRA guidelines) and inferred from the global spatial distribution. The PRA revealed a substantial risk to the EPPO region and Central and Western Africa, highlighting the desirability of avoiding an invasion by P. hysterophorus. We also consider the effects of climate change on the modelled risks. The climate change scenario indicated the risk of substantial further spread of P. hysterophorus in temperate northern hemisphere regions (North America, Europe and the northern Middle East), and also high elevation equatorial regions (Western Brazil, Central Africa, and South East Asia) if minimum temperatures increase substantially. Downscaling the climate model using habitat factors resulted in substantial (approximately 22–53%) reductions in the areas estimated to be endangered. Applying expert assessments as to suitable habitat classes resulted in the greatest reduction in the estimated endangered area, whereas inferring suitable habitats factors from distribution data identified more land use classes and a larger endangered area. Despite some scaling issues with using a globally conformal Land Use Systems dataset, the inferential downscaling method shows promise as a routine addition to the PRA toolkit, as either a direct model component, or simply as a means of better informing an expert assessment of the suitable habitat

  12. Predicting future thermal habitat suitability of competing native and invasive fish species: from metabolic scope to oceanographic modelling

    PubMed Central

    Marras, Stefano; Cucco, Andrea; Antognarelli, Fabio; Azzurro, Ernesto; Milazzo, Marco; Bariche, Michel; Butenschön, Momme; Kay, Susan; Di Bitetto, Massimiliano; Quattrocchi, Giovanni; Sinerchia, Matteo; Domenici, Paolo

    2015-01-01

    Global increase in sea temperatures has been suggested to facilitate the incoming and spread of tropical invaders. The increasing success of these species may be related to their higher physiological performance compared with indigenous ones. Here, we determined the effect of temperature on the aerobic metabolic scope (MS) of two herbivorous fish species that occupy a similar ecological niche in the Mediterranean Sea: the native salema (Sarpa salpa) and the invasive marbled spinefoot (Siganus rivulatus). Our results demonstrate a large difference in the optimal temperature for aerobic scope between the salema (21.8°C) and the marbled spinefoot (29.1°C), highlighting the importance of temperature in determining the energy availability and, potentially, the distribution patterns of the two species. A modelling approach based on a present-day projection and a future scenario for oceanographic conditions was used to make predictions about the thermal habitat suitability (THS, an index based on the relationship between MS and temperature) of the two species, both at the basin level (the whole Mediterranean Sea) and at the regional level (the Sicilian Channel, a key area for the inflow of invasive species from the Eastern to the Western Mediterranean Sea). For the present-day projection, our basin-scale model shows higher THS of the marbled spinefoot than the salema in the Eastern compared with the Western Mediterranean Sea. However, by 2050, the THS of the marbled spinefoot is predicted to increase throughout the whole Mediterranean Sea, causing its westward expansion. Nevertheless, the regional-scale model suggests that the future thermal conditions of Western Sicily will remain relatively unsuitable for the invasive species and could act as a barrier for its spread westward. We suggest that metabolic scope can be used as a tool to evaluate the potential invasiveness of alien species and the resilience to global warming of native species. PMID:27293680

  13. Predicting future thermal habitat suitability of competing native and invasive fish species: from metabolic scope to oceanographic modelling.

    PubMed

    Marras, Stefano; Cucco, Andrea; Antognarelli, Fabio; Azzurro, Ernesto; Milazzo, Marco; Bariche, Michel; Butenschön, Momme; Kay, Susan; Di Bitetto, Massimiliano; Quattrocchi, Giovanni; Sinerchia, Matteo; Domenici, Paolo

    2015-01-01

    Global increase in sea temperatures has been suggested to facilitate the incoming and spread of tropical invaders. The increasing success of these species may be related to their higher physiological performance compared with indigenous ones. Here, we determined the effect of temperature on the aerobic metabolic scope (MS) of two herbivorous fish species that occupy a similar ecological niche in the Mediterranean Sea: the native salema (Sarpa salpa) and the invasive marbled spinefoot (Siganus rivulatus). Our results demonstrate a large difference in the optimal temperature for aerobic scope between the salema (21.8°C) and the marbled spinefoot (29.1°C), highlighting the importance of temperature in determining the energy availability and, potentially, the distribution patterns of the two species. A modelling approach based on a present-day projection and a future scenario for oceanographic conditions was used to make predictions about the thermal habitat suitability (THS, an index based on the relationship between MS and temperature) of the two species, both at the basin level (the whole Mediterranean Sea) and at the regional level (the Sicilian Channel, a key area for the inflow of invasive species from the Eastern to the Western Mediterranean Sea). For the present-day projection, our basin-scale model shows higher THS of the marbled spinefoot than the salema in the Eastern compared with the Western Mediterranean Sea. However, by 2050, the THS of the marbled spinefoot is predicted to increase throughout the whole Mediterranean Sea, causing its westward expansion. Nevertheless, the regional-scale model suggests that the future thermal conditions of Western Sicily will remain relatively unsuitable for the invasive species and could act as a barrier for its spread westward. We suggest that metabolic scope can be used as a tool to evaluate the potential invasiveness of alien species and the resilience to global warming of native species. PMID:27293680

  14. Spatio-Temporal Identification of Areas Suitable for West Nile Disease in the Mediterranean Basin and Central Europe.

    PubMed

    Conte, Annamaria; Candeloro, Luca; Ippoliti, Carla; Monaco, Federica; De Massis, Fabrizio; Bruno, Rossana; Di Sabatino, Daria; Danzetta, Maria Luisa; Benjelloun, Abdennasser; Belkadi, Bouchra; El Harrak, Mehdi; Declich, Silvia; Rizzo, Caterina; Hammami, Salah; Ben Hassine, Thameur; Calistri, Paolo; Savini, Giovanni

    2015-01-01

    West Nile virus (WNV) is a mosquito-transmitted Flavivirus belonging to the Japanese encephalitis antigenic complex of the Flaviviridae family. Its spread in the Mediterranean basin and the Balkans poses a significant risk to human health and forces public health officials to constantly monitor the virus transmission to ensure prompt application of preventive measures. In this context, predictive tools indicating the areas and periods at major risk of WNV transmission are of paramount importance. Spatial analysis approaches, which use environmental and climatic variables to find suitable habitats for WNV spread, can enhance predictive techniques. Using the Mahalanobis Distance statistic, areas ecologically most suitable for sustaining WNV transmission were identified in the Mediterranean basin and Central Europe. About 270 human and equine clinical cases notified in Italy, Greece, Portugal, Morocco, and Tunisia, between 2008 and 2012, have been considered. The environmental variables included in the model were altitude, slope, night time Land Surface Temperature, Normalized Difference Vegetation Index, Enhanced Vegetation Index, and daily temperature range. Seasonality of mosquito population has been modelled and included in the analyses to produce monthly maps of suitable areas for West Nile Disease. Between May and July, the most suitable areas are located in Tunisia, Libya, Egypt, and North Cyprus. Summer/Autumn months, particularly between August and October, characterize the suitability in Italy, France, Spain, the Balkan countries, Morocco, North Tunisia, the Mediterranean coast of Africa, and the Middle East. The persistence of suitable conditions in December is confined to the coastal areas of Morocco, Tunisia, Libya, Egypt, and Israel. PMID:26717483

  15. Spatio-Temporal Identification of Areas Suitable for West Nile Disease in the Mediterranean Basin and Central Europe

    PubMed Central

    Conte, Annamaria; Candeloro, Luca; Ippoliti, Carla; Monaco, Federica; De Massis, Fabrizio; Bruno, Rossana; Di Sabatino, Daria; Danzetta, Maria Luisa; Benjelloun, Abdennasser; Belkadi, Bouchra; El Harrak, Mehdi; Declich, Silvia; Rizzo, Caterina; Hammami, Salah; Ben Hassine, Thameur; Calistri, Paolo; Savini, Giovanni

    2015-01-01

    West Nile virus (WNV) is a mosquito-transmitted Flavivirus belonging to the Japanese encephalitis antigenic complex of the Flaviviridae family. Its spread in the Mediterranean basin and the Balkans poses a significant risk to human health and forces public health officials to constantly monitor the virus transmission to ensure prompt application of preventive measures. In this context, predictive tools indicating the areas and periods at major risk of WNV transmission are of paramount importance. Spatial analysis approaches, which use environmental and climatic variables to find suitable habitats for WNV spread, can enhance predictive techniques. Using the Mahalanobis Distance statistic, areas ecologically most suitable for sustaining WNV transmission were identified in the Mediterranean basin and Central Europe. About 270 human and equine clinical cases notified in Italy, Greece, Portugal, Morocco, and Tunisia, between 2008 and 2012, have been considered. The environmental variables included in the model were altitude, slope, night time Land Surface Temperature, Normalized Difference Vegetation Index, Enhanced Vegetation Index, and daily temperature range. Seasonality of mosquito population has been modelled and included in the analyses to produce monthly maps of suitable areas for West Nile Disease. Between May and July, the most suitable areas are located in Tunisia, Libya, Egypt, and North Cyprus. Summer/Autumn months, particularly between August and October, characterize the suitability in Italy, France, Spain, the Balkan countries, Morocco, North Tunisia, the Mediterranean coast of Africa, and the Middle East. The persistence of suitable conditions in December is confined to the coastal areas of Morocco, Tunisia, Libya, Egypt, and Israel. PMID:26717483

  16. Importance of weighting for multi-variable habitat suitability index model: A case study of winter-spring cohort of Ommastrephes bartramii in the Northwestern Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Gong, Caixia; Chen, Xinjun; Gao, Feng; Chen, Yong

    2012-06-01

    Weighting values for different habitat variables used in multi-factor habitat suitability index (HSI) modeling reflect the relative influences of different variables on distribution of fish species. Using the winter-spring cohort of neon flying squid ( Ommastrephes bartramii) in the Northwestern Pacific Ocean as an example, we evaluated the impact of different weighting schemes on the HSI models based on sea surface temperature, gradient of sea surface temperature and sea surface height. We compared differences in predicted fishing effort and HSI values resulting from different weighting. The weighting for different habitat variables could greatly influence HSI modeling and should be carefully done based on their relative importance in influencing the resource spatial distribution. Weighting in a multi-factor HSI model should be further studied and optimization methods should be developed to improve forecasting squid spatial distributions.

  17. Phylogeography, historical demography and habitat suitability modelling of freshwater fishes inhabiting seasonally fluctuating Mediterranean river systems: a case study using the Iberian cyprinid Squalius valentinus.

    PubMed

    Perea, S; Doadrio, I

    2015-07-01

    The Mediterranean freshwater fish fauna has evolved under constraints imposed by the seasonal weather/hydrological patterns that define the Mediterranean climate. These conditions have influenced the genetic and demographic structure of aquatic communities since their origins in the Mid-Pliocene. Freshwater species in Mediterranean-type climates will likely constitute genetically well-differentiated populations, to varying extents depending on basin size, as a consequence of fragmentation resulting from drought/flood cycles. We developed an integrative framework to study the spatial patterns in genetic diversity, demographic trends, habitat suitability modelling and landscape genetics, to evaluate the evolutionary response of Mediterranean-type freshwater fish to seasonal fluctuations in weather. To test this evolutionary response, the model species used was Squalius valentinus, an endemic cyprinid of the Spanish Levantine area, where seasonal weather fluctuations are extreme, although our findings may be extrapolated to other Mediterranean-type species. Our results underscore the significant role of the Mediterranean climate, along with Pleistocene glaciations, in diversification of S. valentinus. We found higher nuclear diversity in larger drainage basins, but higher mitochondrial diversity correlated to habitat suitability rather than basin size. We also found strong correlation between genetic structure and climatic factors associated with Mediterranean seasonality. Demographic and migration analyses suggested population expansion during glacial periods that also contributed to the current genetic structure of S. valentinus populations. The inferred models support the significant contribution of precipitation and temperature to S. valentinus habitat suitability and allow recognizing areas of habitat stability. We highlight the importance of stable habitat conditions, fostered by typical karstic springs found on the Mediterranean littoral coasts, for the

  18. The Cross River gorillas (Gorilla gorilla diehli) at Mawambi Hills, South-West Cameroon: habitat suitability and vulnerability to anthropogenic disturbance.

    PubMed

    Etiendem, Denis N; Funwi-Gabga, Neba; Tagg, Nikki; Hens, Luc; Indah, Eni K

    2013-01-01

    Only about 300 individuals of the Cross River gorilla (CRG; Gorilla gorilla diehli) survive today. The subspecies is endemic to approximately 12-14 sites at the Cameroon-Nigeria border, and is critically endangered. To understand survival prospects of the CRG at Mawambi Hills, Cameroon, a maximum entropy (MaxEnt) distribution model was used to predict the distribution of gorillas. Overall, 24% of the study area was predicted to be suitable for gorillas. The most important predictors of gorilla distribution were elevation as a surrogate for accessibility (52.4%), distance to nearby villages which represents proximity to anthropogenic disturbance (22.7%), and slope steepness as a proxy for security (19.4%). Gorillas mainly occupied slopes of steep hills and avoided areas of human disturbance. To evaluate the spatial relationship between gorilla distribution and human activities, the predicted habitat suitability map was overlaid with a kernel density map of human activities. A positive correlation was found between locations of human activity and suitable habitat for gorillas (r = 0.5). This suggests that anthropogenic pressures in previously unused forest areas are increasing as a result of resource depletion at lower altitudes, consequently putting the gorillas at greater risk. Conservation management plans that seek to reduce human encroachment into habitats preferred by gorillas such as steep hills will probably contribute to gorilla survival. PMID:23307035

  19. Suitability of the ALien Biotic IndEX (ALEX) for assessing invasion of macroalgae across different Mediterranean habitats.

    PubMed

    Piazzi, Luigi; Gennaro, Paola; Ceccherelli, Giulia

    2015-08-15

    The ALien Biotic IndEX (ALEX) has been recently proposed to evaluate biological invasions in soft-bottom macro-invertebrate assemblages. The present paper proposes the use of ALEX in sessile assemblages of Mediterranean hard bottom habitats and tests it along gradients of invasion. For five invasive macroalgae a variable number of case studies per each of four habitats were examined from the available data sets. For each case study samples were attributed to four levels of invasion depending on the abundance of the invading macroalgae. Results showed that the application of ALEX to sessile assemblages of hard bottoms allows to qualify the level of invasion along the considered gradients. Moreover, the decline of index values matched the impact of invasion on species number of the assemblages. Results also suggest that the concurrent use of ALEX and indices of benthic quality status can be a valuable tool to assess biopollution in hard bottom habitats. PMID:26073799

  20. Effect of spatial and temporal scales on habitat suitability modeling: A case study of Ommastrephes bartramii in the northwest pacific ocean

    NASA Astrophysics Data System (ADS)

    Gong, Caixia; Chen, Xinjun; Gao, Feng; Tian, Siquan

    2014-12-01

    Temporal and spatial scales play important roles in fishery ecology, and an inappropriate spatio-temporal scale may result in large errors in modeling fish distribution. The objective of this study is to evaluate the roles of spatio-temporal scales in habitat suitability modeling, with the western stock of winter-spring cohort of neon flying squid ( Ommastrephes bartramii) in the northwest Pacific Ocean as an example. In this study, the fishery-dependent data from the Chinese Mainland Squid Jigging Technical Group and sea surface temperature (SST) from remote sensing during August to October of 2003-2008 were used. We evaluated the differences in a habitat suitability index model resulting from aggregating data with 36 different spatial scales with a combination of three latitude scales (0.5°, 1° and 2°), four longitude scales (0.5°, 1°, 2° and 4°), and three temporal scales (week, fortnight, and month). The coefficients of variation (CV) of the weekly, biweekly and monthly suitability index (SI) were compared to determine which temporal and spatial scales of SI model are more precise. This study shows that the optimal temporal and spatial scales with the lowest CV are month, and 0.5° latitude and 0.5° longitude for O. bartramii in the northwest Pacific Ocean. This suitability index model developed with an optimal scale can be cost-effective in improving forecasting fishing ground and requires no excessive sampling efforts. We suggest that the uncertainty associated with spatial and temporal scales used in data aggregations needs to be considered in habitat suitability modeling.

  1. Modeling amphibian energetics, habitat suitability, and movements of western toads, Anaxyrus (=Bufo) boreas, across present and future landscapes

    USGS Publications Warehouse

    Bartelt, Paul E.; Klaver, Robert W.; Porter, Warren P.

    2010-01-01

    Effective conservation of amphibian populations requires the prediction of how amphibians use and move through a landscape. Amphibians are closely coupled to their physical environment. Thus an approach that uses the physiological attributes of amphibians, together with knowledge of their natural history, should be helpful. We used Niche Mapper™ to model the known movements and habitat use patterns of a population of Western toads (Anaxyrus (=Bufo) boreas) occupying forested habitats in southeastern Idaho. Niche Mapper uses first principles of environmental biophysics to combine features of topography, climate, land cover, and animal features to model microclimates and animal physiology and behavior across landscapes. Niche Mapper reproduced core body temperatures (Tc) and evaporation rates of live toads with average errors of 1.6 ± 0.4 °C and 0.8 ± 0.2 g/h, respectively. For four different habitat types, it reproduced similar mid-summer daily temperature patterns as those measured in the field and calculated evaporation rates (g/h) with an average error rate of 7.2 ± 5.5%. Sensitivity analyses indicate these errors do not significantly affect estimates of food consumption or activity. Using Niche Mapper we predicted the daily habitats used by free-ranging toads; our accuracy for female toads was greater than for male toads (74.2 ± 6.8% and 53.6 ± 15.8%, respectively), reflecting the stronger patterns of habitat selection among females. Using these changing to construct a cost surface, we also reconstructed movement paths that were consistent with field observations. The effect of climate warming on toads depends on the interaction of temperature and atmospheric moisture. If climate change occurs as predicted, results from Niche Mapper suggests that climate warming will increase the physiological cost of landscapes thereby limiting the activity for toads in different habitats.

  2. Testing Cort-Fitness and Cort-Adaptation hypotheses in a habitat suitability gradient for roe deer

    NASA Astrophysics Data System (ADS)

    Escribano-Avila, Gema; Pettorelli, Nathalie; Virgós, Emilio; Lara-Romero, Carlos; Lozano, Jorge; Barja, Isabel; Cuadra, Felipe S.; Puerta, Marisa

    2013-11-01

    According to the Cort-Fitness Hypothesis, higher stress levels (glucocorticoids) in vertebrates are correlated to lower fitness. However, recent studies have failed to validate this hypothesis. A proposed wider framework suggests that reproduction can be perceived as an overload adds up to other environmental challenges that individuals must adjust to. In this case, elevated glucocorticoids could help individuals to allocate resources to reproduction without comprising other functions, leading to the expectation of a positive cort-fitness relationship. This has been proposed as the Cort-Adaptation Hypothesis. Stress levels result from a complex interaction between the environment and the neuroendocrine system of animals. Accounting for physiological functions involved in how animals cope with their environment would help to clarify the relationship between glucocorticoids and animal performance. We used roe deer (Capreolus capreolus) inhabiting diverse habitats in the Iberian Peninsula to: i) test the Cort-Fitness and Cort-Adaptation hypotheses by indexing fitness using a comprehensive physiological approach which takes into account fundamental physiological functions and their trade-offs; and ii) evaluate the link between primary productivity and individuals' condition in a seasonal environment. We evaluated spatial and temporal variation in stress levels, reproductive hormone levels, nutritional status and immune function from fecal samples collected in 2010. Lower stress levels were related to better condition in non-reproductive seasons but not to higher primary productivity. In contrast, stress levels were always positively related to reproductive condition, which was better in most productive habitats. Summer and winter were the less productive seasons and the more challenging for the species in the habitat gradient studied. In winter, reproductive condition traded off against immune function being biased toward immune function in less productive habitats. In

  3. Site fidelity in the Canary Islands stonechat Saxicola dacotiae in relation to spatial and temporal patterns of habitat suitability

    NASA Astrophysics Data System (ADS)

    Illera, Juan Carlos; Díaz, Mario

    2008-07-01

    We investigate the degree of territory faithfulness of the Canary Islands stonechat Saxicola dacotiae, an endemic bird species of the semi-arid island of Fuerteventura (Canary Islands, Spain), and the spatial and temporal variability of habitat traits related to its breeding success over its whole distribution range. Between 1998 and 2003 we monitored the spatial location of individually marked birds to determine whether they were site faithful. We also analysed the spatial and temporal variability of the abiotic (rainfall) and biotic (food availability, abundance of avian predators and competitors, and nest predation) factors that may influence breeding success in this species. Canary Islands stonechats were strongly site faithful. Out of 106 individuals, 86 (81.0%) were re-sighted during the whole study period, and most re-sightings (76; 88.4%) were in the territory where they were initially caught. Dispersal events were rare both within (1%) and between (≤6%) consecutive years, and detectability of colour-ringed birds was as high as 87%. No significant spatial variation of abiotic and biotic factors affecting success was found at a range of spatial scales. Low spatial variance in the habitat characteristics determining reproductive success could have favoured site fidelity in this species, as costs associated with changing site would not be compensated for by significant increases in survival or breeding prospects in new territories. Strict protection of the areas already occupied by this "Endangered" narrow range endemic bird would be the most effective way of preserving it, due to its strict habitat and microhabitat requirements and its strong site fidelity.

  4. Forecasting Large-Scale Habitat Suitability of European Bustards under Climate Change: The Role of Environmental and Geographic Variables.

    PubMed

    Estrada, Alba; Delgado, M Paula; Arroyo, Beatriz; Traba, Juan; Morales, Manuel B

    2016-01-01

    We modelled the distribution of two vulnerable steppe birds, Otis tarda and Tetrax tetrax, in the Western Palearctic and projected their suitability up to the year 2080. We performed two types of models for each species: one that included environmental and geographic variables (space-included model) and a second one that only included environmental variables (space-excluded model). Our assumption was that ignoring geographic variables in the modelling procedure may result in inaccurate forecasting of species distributions. On the other hand, the inclusion of geographic variables may generate an artificial constraint on future projections. Our results show that space-included models performed better than space-excluded models. While distribution of suitable areas for T. tetrax in the future was approximately the same as at present in the space-included model, the space-excluded model predicted a pronounced geographic change of suitable areas for this species. In the case of O. tarda, the space-included model showed that many areas of current presence shifted to low or medium suitability in the future, whereas a northward expansion of intermediate suitable areas was predicted by the space-excluded one. According to the best models, current distribution of these species can restrict future distribution, probably due to dispersal constraints and site fidelity. Species ranges would be expected to shift gradually over the studied time period and, therefore, we consider it unlikely that most of the current distribution of these species in southern Europe will disappear in less than one hundred years. Therefore, populations currently occupying suitable areas should be a priority for conservation policies. Our results also show that climate-only models may have low explanatory power, and could benefit from adjustments using information on other environmental variables and biological traits; if the latter are not available, including the geographic predictor may improve the

  5. Forecasting Large-Scale Habitat Suitability of European Bustards under Climate Change: The Role of Environmental and Geographic Variables

    PubMed Central

    Estrada, Alba; Delgado, M. Paula; Arroyo, Beatriz; Traba, Juan; Morales, Manuel B.

    2016-01-01

    We modelled the distribution of two vulnerable steppe birds, Otis tarda and Tetrax tetrax, in the Western Palearctic and projected their suitability up to the year 2080. We performed two types of models for each species: one that included environmental and geographic variables (space-included model) and a second one that only included environmental variables (space-excluded model). Our assumption was that ignoring geographic variables in the modelling procedure may result in inaccurate forecasting of species distributions. On the other hand, the inclusion of geographic variables may generate an artificial constraint on future projections. Our results show that space-included models performed better than space-excluded models. While distribution of suitable areas for T. tetrax in the future was approximately the same as at present in the space-included model, the space-excluded model predicted a pronounced geographic change of suitable areas for this species. In the case of O. tarda, the space-included model showed that many areas of current presence shifted to low or medium suitability in the future, whereas a northward expansion of intermediate suitable areas was predicted by the space-excluded one. According to the best models, current distribution of these species can restrict future distribution, probably due to dispersal constraints and site fidelity. Species ranges would be expected to shift gradually over the studied time period and, therefore, we consider it unlikely that most of the current distribution of these species in southern Europe will disappear in less than one hundred years. Therefore, populations currently occupying suitable areas should be a priority for conservation policies. Our results also show that climate-only models may have low explanatory power, and could benefit from adjustments using information on other environmental variables and biological traits; if the latter are not available, including the geographic predictor may improve the

  6. Land-use change reduces habitat suitability for supporting managed honey bee colonies in the Northern Great Plains.

    PubMed

    Otto, Clint R V; Roth, Cali L; Carlson, Benjamin L; Smart, Matthew D

    2016-09-13

    Human reliance on insect pollination services continues to increase even as pollinator populations exhibit global declines. Increased commodity crop prices and federal subsidies for biofuel crops, such as corn and soybeans, have contributed to rapid land-use change in the US Northern Great Plains (NGP), changes that may jeopardize habitat for honey bees in a part of the country that supports >40% of the US colony stock. We investigated changes in biofuel crop production and grassland land covers surrounding ∼18,000 registered commercial apiaries in North and South Dakota from 2006 to 2014. We then developed habitat selection models to identify remotely sensed land-cover and land-use features that influence apiary site selection by Dakota beekeepers. Our study demonstrates a continual increase in biofuel crops, totaling 1.2 Mha, around registered apiary locations in North and South Dakota. Such crops were avoided by commercial beekeepers when selecting apiary sites in this region. Furthermore, our analysis reveals how grasslands that beekeepers target when selecting commercial apiary locations are becoming less common in eastern North and South Dakota, changes that may have lasting impact on pollinator conservation efforts. Our study highlights how land-use change in the NGP is altering the landscape in ways that are seemingly less conducive to beekeeping. Our models can be used to guide future conservation efforts highlighted in the US national pollinator health strategy by identifying areas that support high densities of commercial apiaries and that have exhibited significant land-use changes. PMID:27573824

  7. Land-use change reduces habitat suitability for supporting managed honey bee colonies in the Northern Great Plains

    USGS Publications Warehouse

    Otto, Clint R.; Roth, Cali; Carlson, Benjamin; Smart, Matthew

    2016-01-01

    Human reliance on insect pollination services continues to increase even as pollinator populations exhibit global declines. Increased commodity crop prices and federal subsidies for biofuel crops, such as corn and soybeans, have contributed to rapid land-use change in the US Northern Great Plains (NGP), changes that may jeopardize habitat for honey bees in a part of the country that supports >40% of the US colony stock. We investigated changes in biofuel crop production and grassland land covers surrounding ∼18,000 registered commercial apiaries in North and South Dakota from 2006 to 2014. We then developed habitat selection models to identify remotely sensed land-cover and land-use features that influence apiary site selection by Dakota beekeepers. Our study demonstrates a continual increase in biofuel crops, totaling 1.2 Mha, around registered apiary locations in North and South Dakota. Such crops were avoided by commercial beekeepers when selecting apiary sites in this region. Furthermore, our analysis reveals how grasslands that beekeepers target when selecting commercial apiary locations are becoming less common in eastern North and South Dakota, changes that may have lasting impact on pollinator conservation efforts. Our study highlights how land-use change in the NGP is altering the landscape in ways that are seemingly less conducive to beekeeping. Our models can be used to guide future conservation efforts highlighted in the US national pollinator health strategy by identifying areas that support high densities of commercial apiaries and that have exhibited significant land-use changes.

  8. Defining Landscape Resistance Values in Least-Cost Connectivity Models for the Invasive Grey Squirrel: A Comparison of Approaches Using Expert-Opinion and Habitat Suitability Modelling

    PubMed Central

    Stevenson-Holt, Claire D.; Watts, Kevin; Bellamy, Chloe C.; Nevin, Owen T.; Ramsey, Andrew D.

    2014-01-01

    Least-cost models are widely used to study the functional connectivity of habitat within a varied landscape matrix. A critical step in the process is identifying resistance values for each land cover based upon the facilitating or impeding impact on species movement. Ideally resistance values would be parameterised with empirical data, but due to a shortage of such information, expert-opinion is often used. However, the use of expert-opinion is seen as subjective, human-centric and unreliable. This study derived resistance values from grey squirrel habitat suitability models (HSM) in order to compare the utility and validity of this approach with more traditional, expert-led methods. Models were built and tested with MaxEnt, using squirrel presence records and a categorical land cover map for Cumbria, UK. Predictions on the likelihood of squirrel occurrence within each land cover type were inverted, providing resistance values which were used to parameterise a least-cost model. The resulting habitat networks were measured and compared to those derived from a least-cost model built with previously collated information from experts. The expert-derived and HSM-inferred least-cost networks differ in precision. The HSM-informed networks were smaller and more fragmented because of the higher resistance values attributed to most habitats. These results are discussed in relation to the applicability of both approaches for conservation and management objectives, providing guidance to researchers and practitioners attempting to apply and interpret a least-cost approach to mapping ecological networks. PMID:25380289

  9. Assessment of Habitat Suitability Is Affected by Plant-Soil Feedback: Comparison of Field and Garden Experiment

    PubMed Central

    Hemrová, Lucie; Knappová, Jana; Münzbergová, Zuzana

    2016-01-01

    Background Field translocation experiments (i.e., the introduction of seeds or seedlings of different species into different localities) are commonly used to study habitat associations of species, as well as factors limiting species distributions and local abundances. Species planted or sown in sites where they naturally occur are expected to perform better or equally well compared to sites at which they do not occur or are rare. This, however, contrasts with the predictions of the Janzen-Connell hypothesis and commonly reported intraspecific negative plant-soil feedback. The few previous studies indicating poorer performance of plants at sites where they naturally occur did not explore the mechanisms behind this pattern. Aims and Methods In this study, we used field translocation experiments established using both seeds and seedlings to study the determinants of local abundance of four dominant species in grasslands. To explore the possible effects of intraspecific negative plant-soil feedback on our results, we tested the effect of local species abundance on the performance of the plants in the field experiment. In addition, we set up a garden experiment to explore the intensity of intraspecific as well as interspecific feedback between the dominants used in the experiment. Key Results In some cases, the distribution and local abundances of the species were partly driven by habitat conditions at the sites, and species performed better at their own sites. However, the prevailing pattern was that the local dominants performed worse at sites where they naturally occur than at any other sites. Moreover, the success of plants in the field experiment was lower in the case of higher intraspecific abundance prior to experimental setup. In the garden feedback experiment, two of the species performed significantly worse in soils conditioned by their species than in soils conditioned by the other species. In addition, the performance of the plants was significantly

  10. Spawning areas of eastern Baltic cod revisited: Using hydrodynamic modelling to reveal spawning habitat suitability, egg survival probability, and connectivity patterns

    NASA Astrophysics Data System (ADS)

    Hinrichsen, H.-H.; Lehmann, A.; Petereit, C.; Nissling, A.; Ustups, D.; Bergström, U.; Hüssy, K.

    2016-04-01

    In the highly variable environment of the Baltic Sea two genetically distinct cod stocks exist, one west of the island of Bornholm, which is referred to as the western stock, and one to the east of Bornholm, the eastern stock. A hydrodynamic model combined with a Lagrangian particle tracking technique was utilised to provide spatially and temporally resolved long-term information on environmentally-related (i) spawning habitat size, (ii) egg/yolk-sac larval survival, (iii) separation of causes of mortality, and (iv) connectivity between spawning areas of eastern Baltic cod. Simulations were performed to quantify processes generating heterogeneity in spatial distribution of cod eggs and yolk sac larvae up to the first-feeding stage. The spatial extent of cod eggs represented as virtual drifters is primarily determined by oxygen and salinity conditions at spawning, which define the habitat requirement to which cod's physiology is suited for egg development. The highest habitat suitability occurred in the Bornholm Basin, followed by the Gdansk Deep, while relatively low habitat suitability was obtained for the Arkona and the Gotland Basin. During drift egg and yolk sac larval survival is to a large extent affected by sedimentation. Eggs initially released in the western spawning grounds (Arkona and Bornholm Basin) were more affected by sedimentation than those released in the eastern spawning grounds (Gdansk Deep and Gotland Basin). Highest relative survival of eastern Baltic cod eggs occurred in the Bornholm Basin, with a pronounced decrease towards the Gdansk Deep and the Gotland Basin. Relatively low survival rates in the Gdansk Deep and in the Gotland Basin were attributable to oxygen-dependent mortality. Low oxygen content had almost no impact on survival in the Arkona Basin. For all spawning areas temperature dependent mortality was only evident after severe winters. Egg buoyancy in relation to topographic features like bottom sills and strong bottom slopes