Table 1.
Habitat variables (top) and derived climate variables (bottom) used in general linear models and model selection analyses of relative pika (Ochotona princeps) scat density in the Wind River (2010) and Bighorn (2011) mountain ranges, Wyoming, USA.
Table 2.
Results of general linear models of American pika scat density in the Wind River and Bighorn Ranges, Wyoming, USA (2010–2011) in relation to habitat variables with models displayed based on Akaike’s information criterion corrected for small sample size (AICc).
Fig 1.
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.
Fig 2.
American pika scat density as a function of forage availability across elevation.
Scat/m2 in the Wind River (a; n = 43 sites) and Bighorn (b; n = 40) ranges in Wyoming, USA, 2010 and 2011, respectively. Elevation ranges are: < 3100m (white), > 3100 and < 3600m (gray), > 3600m (black); n = 43 sites.
Table 3.
Results of models fit to relative American pika scat density at a subset (n = 27) of Wind River Range (Wyoming, USA) sites (2010) using temperature sensor data showing the five best-supported models that replaced elevation with climate effects, as well as the best habitat variable model and the null model.
Table 4.
Results of models fit to relative American pika scat density at a subset (n = 27) of Wind River Range (Wyoming, USA) sites (2010) using iButton temperature sensor data showing the best models of the full suite.
Fig 3.
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.
Fig 4.
Relationship between American pika scat density and number of days below -5°C.
Data were recorded with temperature loggers at 27 sites in the Wind River Range, Wyoming, USA from one year starting in August 2010. Colors represent different elevation ranges (white: < 3300m, (n = 9), gray: 3300-3600m, (n = 14); black: > 3600 m, (n = 4). The curve represents the predicted relationship from the top model of the temperature sensor analysis (adj. r2 = 0.29).
Fig 5.
Correlations between four local climate measures and elevation.
Climate variables included from top to bottom: number of days above 10°C, adj. r2 = 0.34; mean summer temperature, adj. r2 = 0.28; total degree days (°C*days), adj. r2 = 0.33; and mean winter temperature, adj. r2 = 0.09. All data were obtained via ibutton sensors deployed at 27 sites in the Wind River Range, Wyoming, USA for one year starting in August 2010.
Fig 6.
Correlations between American pika scat density and four local climate measures.
Climate variables from top to bottom: number of days above 10°C, adj. r2 = 0.06; mean summer temperature, adj. r2 = 0.02; total degree days, adj. r2 = 0.04; and mean winter temperature, adj. r2 = 0.01; were obtained via ibutton sensors in the Wind River Range, Wyoming, USA deployed during August, 2010 –August 2011.