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Abundance and other aspects of population ecology have long been known to contribute to shaping the geography of species' distributions. In particular, abundance patterns have recently been shown to negatively correlate with environmental distance from conditions in the center of a species' abiotic niche, rather than vary with distance from the geographic center of a species' distribution. We tested for such associations across 8 species of endangered or threatened bird species in North America using population trend data derived from > 4 decades of North American Breeding Bird Surveys. Although we found no consistent overall pattern, we did observe negative population trends at conditions that were the most extreme within species' niches. This suggests that niche peripherality is a relevant factor to consider in conservation planning. Specifically, environmentally peripheral sites may be poor places in which to protect populations of endangered and threatened species, irrespective of how centrally they may occur within species' geographic distributions.

Species invasions represent a significant dimension of global change yet the dynamics of invasions remain poorly understood and are considered rather unpredictable. We explored interannual dynamics of the invasion process in the Eurasian collared dove () and tested whether the advance of the invasion front of the species in North America relates to centrality (versus peripherality) within its estimated fundamental ecological niche. We used ecological niche modelling approaches to estimate the dimensions of the fundamental ecological niche on the Old World distribution of the species, and then transferred that model to the New World as measures of centrality versus peripherality within the niche for the species. Although our hypothesis was that the invasion front would advance faster over more favourable (i.e. more central) conditions, the reverse was the case: the invasion expanded faster in areas presenting less favourable (i.e. more peripheral) conditions for the species as it advanced across North America. This result offers a first view of a predictive approach to the dynamics of species' invasions, and thereby has relevant implications for the management of invasive species, as such a predictive understanding would allow better anticipation of coming steps and advances in the progress of invasions, important to designing and guiding effective remediation and mitigation efforts.

Identification and characterization of seasonal migration routes and stopover sites has been recognized as important to the conservation of migratory species. This project utilizes multiple regression models including circular-linear regression to identify associations between route choice, travel speed, and environmental preferences using trajectory data of migratory Arctic Terns (Sterna paradisaea) and environmental data obtained through remote-sensing techniques. Results of this study suggest that route choice on the southward post-breeding migration route may be more dependent on underlying environment than the northward postwintering migration route. In contrast, travel speed was variably associated with underlying environment between southward and northward migrations, including several differences regarding the impact of interactions between environmental variables. These results reveal the importance of using multiple metrics in the estimation of spatial resistance and highlight conflicts between the theoretical resistance framework of GIS and movement analysis methods.