Integrating spatial and temporal processes to understand the effects of multiple environmental stressors on ecosystems

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Human-induced environmental stressors, such as global climate change, introduction of non-indigenous species, and alterations in land use, water quality and habitat, are among the leading drivers of ecosystem change and loss of biodiversity. My goal is to understand the response of freshwater systems to environmental stressors. Few studies predict the effects of multiple interacting environmental stressors on species, and fewer studies have been conducted at the community level. We will develop multivariate statistical models to determine the effects of multiple human-induced environmental stressors on warmwater, coolwater, and coldwater fish communities at the extents of their ranges in Ontario and Wisconsin. We will compare extremes in range expansion and contraction, monitoring the northward dispersal of warmwater fish, and the extirpation of coldwater fish in the south. These models will allow for an assessment of how environmental variability will affect freshwater fish communities under different climate change, invasive species, and land-use scenarios. Subsequently, we will determine how multiple environmental stressors exert their influence across multiple spatial scales. We will employ spatial statistical methods to develop models identifying biotic and abiotic determinants influencing species distributions at local, regional, continental, and global spatial scales. We will apply scenarios of environmental change to predict how multiple environmental stressors impact the extirpation of native fish communities at a range of spatial scales. Finally, using ice-cover records for over 75 lakes across the Northern Hemisphere spanning up to 550 years, we will integrate temporal processes at short-, medium-, and long-time scales to differentiate the role of natural oscillatory dynamics and anthropogenically induced climatic change in an effort to determine how patterns of ice phenology have changed across space and time. Therefore, we propose to improve our understanding of the response of aquatic ecosystems to threats on water quality and biodiversity in Canadian lakes within a global context.