Temporal changes in species composition affect a ubiquitous species’ use of habitat patches

Across landscapes, shifts in species composition often co‐occur with shifts in structural or abiotic habitat features, making it difficult to disentangle the role of competitors and environment on assessments of patch quality. Using over two decades of rodent community data from a long‐term experiment, we show that a small, ubiquitous granivore (Chaetodipus penicillatus) shifted its use of different experimental treatments with the establishment of a novel competitor, C. baileyi. Shifts in residency, probability of movement between patches, and the arrival of new individuals in patches altered which treatment supported the highest abundances of C. penicillatus. Our results suggest that the establishment of a new species worsened the quality of the originally preferred treatment, likely by impacting resource availability. Paradoxically, the presence of the new species also increased C. penicillatus’ use of the less preferred treatment, potentially through shifts in the competitive network on those plots. Species often exist in landscapes consisting of a patchwork of habitats, some of which are conducive to a species’ survival and reproduction and others that are less suitable. Building upon intraspecific habitat selection (Fretwell and Lucas 1969) and optimal patch use theory (Charnov 1976, Brown 1988), numerous studies have shown that interspecific habitat selection can act as a potential mechanism of species coexistence (e.g., Grant 1971, Schoener 1974, Morris 1989, 2003). Landscape heterogeneity creates niche opportunities (Comins and Noble 1985) while variability in patch connectivity supports scenarios where populations can be rescued from extinction by dispersal (Brown and Kodric‐Brown 1977) or where species can find isolated refuges when they would otherwise be driven extinct (Sedell et al. 1990). However, changes in patch conditions also take place through time (Ernest et al. 2008), resulting in patches that vary in their suitability for a species as conditions change. Despite the fact that population dynamics and regional processes (i.e., dispersal, colonization, extinction) are inherently both spatial and temporal, temporal variation in patches is rarely incorporated into studies on patch preference. While many studies on habitat selection focus on differences between patches in structural habitat (e.g., vegetation structure) or abiotic conditions (e.g., temperature, soil conditions), species density and composition can also affect patch preference (Grant 1971, Danielson and Gaines 1987, Morris 1989, Abramsky et al. 1992). Understanding a