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Resource selection by the California condor (Gymnogyps californianus) relative to terrestrial-based habitats and meteorological conditions.

Rivers JW, Johnson JM, Haig SM, Schwarz CJ, Glendening JW, Burnett LJ, George D, Grantham J - PLoS ONE (2014)

Bottom Line: We found little evidence of systematic effects between individual characteristics (i.e., sex, age, breeding status) or components of the species management program (i.e., release site, rearing method) relative to meteorological conditions.Our findings indicate that habitat type and meteorological conditions can interact in complex ways to influence condor resource selection across landscapes, which is noteworthy given the extent of anthropogenic stressors that may impact condor populations (e.g., lead poisoning, wind energy development).Additional studies will be valuable to assess small-scale condor movements in light of these stressors to help minimize their risk to this critically endangered species.

View Article: PubMed Central - PubMed

Affiliation: Department of Forest Ecosystems and Society, Oregon State University, Corvallis, Oregon, United States of America.

ABSTRACT
Condors and vultures are distinct from most other terrestrial birds because they use extensive soaring flight for their daily movements. Therefore, assessing resource selection by these avian scavengers requires quantifying the availability of terrestrial-based habitats, as well as meteorological variables that influence atmospheric conditions necessary for soaring. In this study, we undertook the first quantitative assessment of habitat- and meteorological-based resource selection in the endangered California condor (Gymnogyps californianus) within its California range and across the annual cycle. We found that condor use of terrestrial areas did not change markedly within the annual cycle, and that condor use was greatest for habitats where food resources and potential predators could be detected and where terrain was amenable for taking off from the ground in flight (e.g., sparse habitats, coastal areas). Condors originating from different release sites differed in their use of habitat, but this was likely due in part to variation in habitats surrounding release sites. Meteorological conditions were linked to condor use of ecological subregions, with thermal height, thermal velocity, and wind speed having both positive (selection) and negative (avoidance) effects on condor use in different areas. We found little evidence of systematic effects between individual characteristics (i.e., sex, age, breeding status) or components of the species management program (i.e., release site, rearing method) relative to meteorological conditions. Our findings indicate that habitat type and meteorological conditions can interact in complex ways to influence condor resource selection across landscapes, which is noteworthy given the extent of anthropogenic stressors that may impact condor populations (e.g., lead poisoning, wind energy development). Additional studies will be valuable to assess small-scale condor movements in light of these stressors to help minimize their risk to this critically endangered species.

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Habitat classifications of landcover in California.The range of primary concern according to the 1984 California Condor Recovery Plan [60] is shown by a solid black outline with condor release sites considered in this study (crosses). Note that Bitter Creek NWR and Hopper Mountain NWR are combined for analysis because they are both part of the Hopper Mountain National Wildlife Refuge Complex.
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pone-0088430-g001: Habitat classifications of landcover in California.The range of primary concern according to the 1984 California Condor Recovery Plan [60] is shown by a solid black outline with condor release sites considered in this study (crosses). Note that Bitter Creek NWR and Hopper Mountain NWR are combined for analysis because they are both part of the Hopper Mountain National Wildlife Refuge Complex.

Mentions: We used data from Global Positioning System (GPS) transmitters collected from July 2003–December 2010 to assess resource selection of condors that originated from three release sites in California (Fig. 1). Hopper Mountain National Wildlife Refuge and Bittercreek National Wildlife Refuge are part of the Hopper Mountain National Wildlife Refuge Complex and managed by the U.S. Fish and Wildlife Service (hereafter Hopper Mountain); Pinnacles National Park (hereafter Pinnacles) is managed by the National Park Service; and the Big Sur release site (hereafter Big Sur) is managed by Ventana Wildlife Society. Hopper Mountain is located inland in southern California, Pinnacles is located inland in central California's Coast Range, and Big Sur is located along the central California coast.


Resource selection by the California condor (Gymnogyps californianus) relative to terrestrial-based habitats and meteorological conditions.

Rivers JW, Johnson JM, Haig SM, Schwarz CJ, Glendening JW, Burnett LJ, George D, Grantham J - PLoS ONE (2014)

Habitat classifications of landcover in California.The range of primary concern according to the 1984 California Condor Recovery Plan [60] is shown by a solid black outline with condor release sites considered in this study (crosses). Note that Bitter Creek NWR and Hopper Mountain NWR are combined for analysis because they are both part of the Hopper Mountain National Wildlife Refuge Complex.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3921182&req=5

pone-0088430-g001: Habitat classifications of landcover in California.The range of primary concern according to the 1984 California Condor Recovery Plan [60] is shown by a solid black outline with condor release sites considered in this study (crosses). Note that Bitter Creek NWR and Hopper Mountain NWR are combined for analysis because they are both part of the Hopper Mountain National Wildlife Refuge Complex.
Mentions: We used data from Global Positioning System (GPS) transmitters collected from July 2003–December 2010 to assess resource selection of condors that originated from three release sites in California (Fig. 1). Hopper Mountain National Wildlife Refuge and Bittercreek National Wildlife Refuge are part of the Hopper Mountain National Wildlife Refuge Complex and managed by the U.S. Fish and Wildlife Service (hereafter Hopper Mountain); Pinnacles National Park (hereafter Pinnacles) is managed by the National Park Service; and the Big Sur release site (hereafter Big Sur) is managed by Ventana Wildlife Society. Hopper Mountain is located inland in southern California, Pinnacles is located inland in central California's Coast Range, and Big Sur is located along the central California coast.

Bottom Line: We found little evidence of systematic effects between individual characteristics (i.e., sex, age, breeding status) or components of the species management program (i.e., release site, rearing method) relative to meteorological conditions.Our findings indicate that habitat type and meteorological conditions can interact in complex ways to influence condor resource selection across landscapes, which is noteworthy given the extent of anthropogenic stressors that may impact condor populations (e.g., lead poisoning, wind energy development).Additional studies will be valuable to assess small-scale condor movements in light of these stressors to help minimize their risk to this critically endangered species.

View Article: PubMed Central - PubMed

Affiliation: Department of Forest Ecosystems and Society, Oregon State University, Corvallis, Oregon, United States of America.

ABSTRACT
Condors and vultures are distinct from most other terrestrial birds because they use extensive soaring flight for their daily movements. Therefore, assessing resource selection by these avian scavengers requires quantifying the availability of terrestrial-based habitats, as well as meteorological variables that influence atmospheric conditions necessary for soaring. In this study, we undertook the first quantitative assessment of habitat- and meteorological-based resource selection in the endangered California condor (Gymnogyps californianus) within its California range and across the annual cycle. We found that condor use of terrestrial areas did not change markedly within the annual cycle, and that condor use was greatest for habitats where food resources and potential predators could be detected and where terrain was amenable for taking off from the ground in flight (e.g., sparse habitats, coastal areas). Condors originating from different release sites differed in their use of habitat, but this was likely due in part to variation in habitats surrounding release sites. Meteorological conditions were linked to condor use of ecological subregions, with thermal height, thermal velocity, and wind speed having both positive (selection) and negative (avoidance) effects on condor use in different areas. We found little evidence of systematic effects between individual characteristics (i.e., sex, age, breeding status) or components of the species management program (i.e., release site, rearing method) relative to meteorological conditions. Our findings indicate that habitat type and meteorological conditions can interact in complex ways to influence condor resource selection across landscapes, which is noteworthy given the extent of anthropogenic stressors that may impact condor populations (e.g., lead poisoning, wind energy development). Additional studies will be valuable to assess small-scale condor movements in light of these stressors to help minimize their risk to this critically endangered species.

Show MeSH
Related in: MedlinePlus