Microhabitat use by plateau pikas: living on the edge

Abstract

Mammals rely on habitat resources for survival and reproduction. We studied microhabitats used by plateau pikas (Ochotona curzoniae) of the Qinghai-Tibetan Plateau. Microhabitat features used by pikas include sedge meadows that provide forage, burrows that provide safety from predators and cover for nests, degraded open-dirt patches, and edges between sedge meadow and open dirt patches that often have a “lip” between those microhabitats. We investigated the extent to which these edges might serve as a preferred pika microhabitat. GIS techniques were used to overlay individual pika home ranges, determined by focal and scan sampling, on a digitized map containing microhabitat features. Regions that contained multiple coinciding individual home ranges, referred to as overlap polygons, were categorized numerically based on the number of individual home ranges that overlapped each polygon. These overlap polygons were used as relative measures of pika activity. We tested the spatial relationship between pika activity and the microhabitat features of edges, burrows, and proportional area of sedge. There was a significant relationship between the number of pikas in an overlap polygon and the number of pikas in an adjacent polygon. This pattern was controlled statistically to test whether activity was influenced by the presence of potentially favorable microhabitat features. Most of the variation in number of pikas that overlapped a habitat polygon was associated with the relative amount of “edge microhabitat” between sedge meadow and degraded open dirt patches (Cohen’s effect size, f2 = 0.91). Neither burrow openings nor sedge had a strong influence on the number of pika home ranges that overlapped. The importance of microhabitat edges appeared high for plateau pikas.

Integrating microclimatic variation in phenological responses to climate change: A 28‐year study in a hibernating mammal

“…Local contrasts in slope angles, sun exposure, soil composition, and vegetation cover can cause climate to vary, through variations in solar radiation, wind exposure, or humidity, from scales of 1–10 km (i.e., mesoclimates) to scales of 0–100 m (i.e., microclimates) (Barry, 1992). Due to a lack of climate data at a fine resolution (<1 km), few studies have examined phenological responses to microclimatic conditions (James et al, 1984; Paruchuri et al, 2019; Potter et al, 2013; Suggitt et al, 2011; Varner & Dearing, 2014).…”

Divergent adaptations in resource‐use traits explain how pikas thrive on the roof of the world

“…This species is known to inhabit shrub landscapes with abundant rocky substrates, where it occupies the cracks of rocks (Liu & Smith, 2018). It has the flattest skull in the genus, which is highly differentiated from those of its closer taxa (Figure 3) and presents biomechanical advantages for exploring narrow crevices, as is well documented in rock-dwelling lizards (Collar et al, 2010;Goodman et al, 2008;Revell et al, 2007) shows a generalist skull form-located in the centre of phylomorphospace and with a low disparity from the overall mean shape-likely reflecting its ability to exploit diverse microhabitats (Paruchuri, Smith, Fan, & Dobson, 2019). Similar reasoning explains why species with a wide elevation range or that inhabit distinct habitats (e.g.…”

Preference for ground cover when selecting burrow entrances in plateau pikas

“…For the “duck” holes, plateau pikas have to burrow from the ground surface. The meadow surface contains “edges” which are preferentially used by pikas—often for initiating burrows (Paruchuri et al., 2019 ), which is an active selection on ground covers. It is worth noting that, there may also exist abandonment of “duck” holes.…”