Limits...
Climate Tolerances and Habitat Requirements Jointly Shape the Elevational Distribution of the American Pika (Ochotona princeps), with Implications for Climate Change Effects.

Yandow LH, Chalfoun AD, Doak DF - PLoS ONE (2015)

Bottom Line: Scat density also increased with temperatures conducive to forage plant growth, and showed a unimodal relationship with the number of days below -5°C, which is modulated by insulating snowpack.Our results provide support for both the forage availability and winter snowpack hypotheses.Especially in montane systems, considering the context-dependent nature of climate effects across regions and elevations as well as interactions between climatic and other critical habitat characteristics, will be essential for predicting future species distributions.

View Article: PubMed Central - PubMed

Affiliation: Department of Zoology and Physiology, University of Wyoming, 1000 East University Avenue, Laramie, Wyoming, 82071, United States of America; Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology (3166), University of Wyoming, 1000 East University Avenue, Laramie, Wyoming, 82071, United States of America.

ABSTRACT
Some of the most compelling examples of ecological responses to climate change are elevational range shifts of individual species, which have been observed throughout the world. A growing body of evidence, however, suggests substantial mediation of simple range shifts due to climate change by other limiting factors. Understanding limiting factors for a species within different contexts, therefore, is critical for predicting responses to climate change. The American pika (Ochotona princeps) is an ideal species for investigating distributions in relation to climate because of their unusual and well-understood natural history as well as observed shifts to higher elevation in parts of their range. We tested three hypotheses for the climatic or habitat characteristics that may limit pika presence and abundance: summer heat, winter snowpack, and forage availability. We performed these tests using an index of pika abundance gathered in a region where environmental influences on pika distribution have not been well-characterized. We estimated relative pika abundance via scat surveys and quantified climatic and habitat characteristics across two North-Central Rocky Mountain Ranges, the Wind River and Bighorn ranges in Wyoming, USA. Pika scat density was highest at mid-elevations and increased linearly with forage availability in both ranges. Scat density also increased with temperatures conducive to forage plant growth, and showed a unimodal relationship with the number of days below -5°C, which is modulated by insulating snowpack. Our results provide support for both the forage availability and winter snowpack hypotheses. Especially in montane systems, considering the context-dependent nature of climate effects across regions and elevations as well as interactions between climatic and other critical habitat characteristics, will be essential for predicting future species distributions.

No MeSH data available.


Related in: MedlinePlus

Summed Akaike weights for local microclimate and forage predictor variables.Summed Akaike weights indicating overall support for predictor variables (f = forage; -5 = number of days below -5°C; 10 = number of days above 10°C; -10 = number of days below -10°C; s = mean summer temperature; td = total degree days; leng = length of the growing season; 0 = days below 0°C; w = mean winter temperature; 15 = number of days above 15°C) in relation to American pika scat density in Wyoming, USA across all models tested.
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pone.0131082.g003: Summed Akaike weights for local microclimate and forage predictor variables.Summed Akaike weights indicating overall support for predictor variables (f = forage; -5 = number of days below -5°C; 10 = number of days above 10°C; -10 = number of days below -10°C; s = mean summer temperature; td = total degree days; leng = length of the growing season; 0 = days below 0°C; w = mean winter temperature; 15 = number of days above 15°C) in relation to American pika scat density in Wyoming, USA across all models tested.

Mentions: AICc results from the suite of models that substituted different local climate variables for elevation largely agreed with the analyses of a larger suite of models (Tables 3 and 4). In particular, patch forage was present in most well-supported models in each suite, and two climate variables—days below -5°C and days above 10°C—were also present in virtually all well-supported models (Tables 3 and 4). Other climate variables that were present in well-supported models included mean summer temperature, mean winter temperature, total degree days, days below -10°C, and growing season length. However, the summed AICc weights, which indicate across-model support for a variable, where by far the highest for the top three variables: forage, days below -5°C, and days above 10°C (Fig 3).


Climate Tolerances and Habitat Requirements Jointly Shape the Elevational Distribution of the American Pika (Ochotona princeps), with Implications for Climate Change Effects.

Yandow LH, Chalfoun AD, Doak DF - PLoS ONE (2015)

Summed Akaike weights for local microclimate and forage predictor variables.Summed Akaike weights indicating overall support for predictor variables (f = forage; -5 = number of days below -5°C; 10 = number of days above 10°C; -10 = number of days below -10°C; s = mean summer temperature; td = total degree days; leng = length of the growing season; 0 = days below 0°C; w = mean winter temperature; 15 = number of days above 15°C) in relation to American pika scat density in Wyoming, USA across all models tested.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4526653&req=5

pone.0131082.g003: Summed Akaike weights for local microclimate and forage predictor variables.Summed Akaike weights indicating overall support for predictor variables (f = forage; -5 = number of days below -5°C; 10 = number of days above 10°C; -10 = number of days below -10°C; s = mean summer temperature; td = total degree days; leng = length of the growing season; 0 = days below 0°C; w = mean winter temperature; 15 = number of days above 15°C) in relation to American pika scat density in Wyoming, USA across all models tested.
Mentions: AICc results from the suite of models that substituted different local climate variables for elevation largely agreed with the analyses of a larger suite of models (Tables 3 and 4). In particular, patch forage was present in most well-supported models in each suite, and two climate variables—days below -5°C and days above 10°C—were also present in virtually all well-supported models (Tables 3 and 4). Other climate variables that were present in well-supported models included mean summer temperature, mean winter temperature, total degree days, days below -10°C, and growing season length. However, the summed AICc weights, which indicate across-model support for a variable, where by far the highest for the top three variables: forage, days below -5°C, and days above 10°C (Fig 3).

Bottom Line: Scat density also increased with temperatures conducive to forage plant growth, and showed a unimodal relationship with the number of days below -5°C, which is modulated by insulating snowpack.Our results provide support for both the forage availability and winter snowpack hypotheses.Especially in montane systems, considering the context-dependent nature of climate effects across regions and elevations as well as interactions between climatic and other critical habitat characteristics, will be essential for predicting future species distributions.

View Article: PubMed Central - PubMed

Affiliation: Department of Zoology and Physiology, University of Wyoming, 1000 East University Avenue, Laramie, Wyoming, 82071, United States of America; Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology (3166), University of Wyoming, 1000 East University Avenue, Laramie, Wyoming, 82071, United States of America.

ABSTRACT
Some of the most compelling examples of ecological responses to climate change are elevational range shifts of individual species, which have been observed throughout the world. A growing body of evidence, however, suggests substantial mediation of simple range shifts due to climate change by other limiting factors. Understanding limiting factors for a species within different contexts, therefore, is critical for predicting responses to climate change. The American pika (Ochotona princeps) is an ideal species for investigating distributions in relation to climate because of their unusual and well-understood natural history as well as observed shifts to higher elevation in parts of their range. We tested three hypotheses for the climatic or habitat characteristics that may limit pika presence and abundance: summer heat, winter snowpack, and forage availability. We performed these tests using an index of pika abundance gathered in a region where environmental influences on pika distribution have not been well-characterized. We estimated relative pika abundance via scat surveys and quantified climatic and habitat characteristics across two North-Central Rocky Mountain Ranges, the Wind River and Bighorn ranges in Wyoming, USA. Pika scat density was highest at mid-elevations and increased linearly with forage availability in both ranges. Scat density also increased with temperatures conducive to forage plant growth, and showed a unimodal relationship with the number of days below -5°C, which is modulated by insulating snowpack. Our results provide support for both the forage availability and winter snowpack hypotheses. Especially in montane systems, considering the context-dependent nature of climate effects across regions and elevations as well as interactions between climatic and other critical habitat characteristics, will be essential for predicting future species distributions.

No MeSH data available.


Related in: MedlinePlus