Postdoctoral Fellow University of Victoria, Canada
Background/Question/Methods
Landscape change alters species’ distributions, and understanding these changes is a key ecological and conservation goal. Species-habitat relationships are often modelled in the absence of syntopic species, but niche theory and emerging empirical research suggests heterospecifics should entrain (and statistically explain) variability in distribution, perhaps synergistically with landscape features. Using three years of camera-trap data we tested for synergistic syntopy-habitat relationships in mammal communities in the western Nearctic boreal forest – a North American epicentre of energy extraction. Using an information-theoretic framework we examined the additive contribution of heterospecifics’ relative abundance, and species/feature interaction terms, to species distribution models built on natural and anthropogenic landscape features. We competed multiple hypotheses about the roles of natural features, anthropogenic features, predators, competitors, and species-habitat interaction terms in explaining relative abundance of carnivores, herbivores, and omnivores / scavengers.
Results/Conclusions
Almost all large boreal mammal species’ distributions – especially carnivores – were markedly affected by co-occurring species. Models including heterospecifics explained distribution better than natural or anthropogenic landscape features alone. Dominant predator (wolf) occurrence was best explained by prey, while prey species were explained by apparent competitors and subdominant predators. Evidence for synergies – as interactions between anthropogenic landscape features and heterospecifics – was strong for coyotes and wolves but variable for other species. Boreal mammals’ spatial distribution is a function of heterospecific co-occurrence as well as landscape features, with synergistic effects observed for some species. Understanding species’ responses to ongoing global anthropogenic landscape change thus requires a multi-taxa approach that incorporates interspecific relationships, requiring a community approach to monitoring. Camera traps can provide this information, and a global network is needed to advance conservation ecology.
