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

American pika scat density as a function of top habitat predictor variables.Scat/m2 as a function of elevation (a) and patch forage availability (b) in the Wind River Range, Wyoming, USA, 2010 (adj. r2 = 0.32), and elevation (c) and perimeter forage availability (d) in the Bighorn Range in 2011 (adj. r2 = 0.40). Lines in each panel represent the predicted relationship of the top model for each range, holding patch forage (a), perimeter forage (c), and elevation (b, d) at their mean values.
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pone.0131082.g001: American pika scat density as a function of top habitat predictor variables.Scat/m2 as a function of elevation (a) and patch forage availability (b) in the Wind River Range, Wyoming, USA, 2010 (adj. r2 = 0.32), and elevation (c) and perimeter forage availability (d) in the Bighorn Range in 2011 (adj. r2 = 0.40). Lines in each panel represent the predicted relationship of the top model for each range, holding patch forage (a), perimeter forage (c), and elevation (b, d) at their mean values.

Mentions: American pika scat/m2 ranged from 0.04 to 0.63 at sites (n = 43) in the Winds in 2010 with a mean of 0.27 ± 0.027 SE. The AICc model with the strongest support included linear and quadratic terms of elevation and a linear term of patch forage, with other well-supported models including similar variables (Table 2). A model had very little support (AICc = -22.8; ΔAICc = 12.6; Akaike Weight = 0.00). Summed Akaike weights of all models that included elevation and patch forage showed strong support for those variables (summed Akaike weights = 0.73 and 0.98, respectively). Scat density increased with elevation to an approximate apex at about 3600 m, beyond which density decreased (Fig 1A). The best-supported relationship between patch forage and scat/m2 was linear and positive (Fig 1B). Other variables had little to no support as predictors of scat density, including aspect, talus depth, and elevation difference to summit.


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)

American pika scat density as a function of top habitat predictor variables.Scat/m2 as a function of elevation (a) and patch forage availability (b) in the Wind River Range, Wyoming, USA, 2010 (adj. r2 = 0.32), and elevation (c) and perimeter forage availability (d) in the Bighorn Range in 2011 (adj. r2 = 0.40). Lines in each panel represent the predicted relationship of the top model for each range, holding patch forage (a), perimeter forage (c), and elevation (b, d) at their mean values.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0131082.g001: American pika scat density as a function of top habitat predictor variables.Scat/m2 as a function of elevation (a) and patch forage availability (b) in the Wind River Range, Wyoming, USA, 2010 (adj. r2 = 0.32), and elevation (c) and perimeter forage availability (d) in the Bighorn Range in 2011 (adj. r2 = 0.40). Lines in each panel represent the predicted relationship of the top model for each range, holding patch forage (a), perimeter forage (c), and elevation (b, d) at their mean values.
Mentions: American pika scat/m2 ranged from 0.04 to 0.63 at sites (n = 43) in the Winds in 2010 with a mean of 0.27 ± 0.027 SE. The AICc model with the strongest support included linear and quadratic terms of elevation and a linear term of patch forage, with other well-supported models including similar variables (Table 2). A model had very little support (AICc = -22.8; ΔAICc = 12.6; Akaike Weight = 0.00). Summed Akaike weights of all models that included elevation and patch forage showed strong support for those variables (summed Akaike weights = 0.73 and 0.98, respectively). Scat density increased with elevation to an approximate apex at about 3600 m, beyond which density decreased (Fig 1A). The best-supported relationship between patch forage and scat/m2 was linear and positive (Fig 1B). Other variables had little to no support as predictors of scat density, including aspect, talus depth, and elevation difference to summit.

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