Research Objectives

 
The objective of this project is to study the spatial, environmental and climatic factors affecting habitat occupancy by collared pikas. 

Pikas (primarily Ochotona princeps, American pika) have long been treated as a model species for studies of metapopulation dynamics since they live in relatively discrete population units (called “metapopulations”) that are comprised of several local populations, each inhabiting an individual talus patch ( Franken 2002; Franken and Hik 2004; Moilenan et al 1998; Smith 1974).  

Much of the research on pika population dynamics has focussed on the effect of spatial configuration of patches (e.g., area and connectivity) on population size and the probability of extirpation and re-colonization of local populations (Hanski 2002, Moilenan et al. 1998).  More recently, studies have begun to look at other factors influencing these dynamics, such as habitat quality and temperature (Bruggeman 2010; Franken 2002; Franken and Hik 2004), primarily to better understand the implications of changes in these factors for pika conservation.  As collared pikas are thought to be particularly vulnerable to climate change, a consideration of the broader set of factors influencing their populations is considered timely and important. 

The following response and predictor variables were considered in this study:

Response variables include population measures at three spatial scales:

                                      Study area   ~   metapopulatoin

                                      Talus patch  ~   local population

                                     Haypile         ~   individual animals

Predictor variables include multiple measures of spatial configuration, the physical environment associated with habitat, and regional climate.


A schematic of the analysis components is provided in Figure 2.

 Figure 2.  Schematic showing response and predictor variables at three spatial scales

 

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