Recreational boating, landscape configuration, and local habitat structure as drivers of odonate community composition in an island setting

Abstract

Abstract Anthropogenic impacts to aquatic and terrestrial ecosystems are ubiquitous. Among these, local impacts to freshwater coastal wetlands from recreational boating are potentially severe. We determine the relative contribution of natural factors (local habitat structure and landscape configuration) and estimated impact from anthropogenic factors (i.e. pressure from recreational boating) to odonate community composition. Odonate adults and exuviae were sampled from 17 islands within the 30 000 islands of the Georgian Bay Region of Lake Huron (Ontario, Canada). These islands experience a gradient of boating pressure from four marinas. The magnitude of impacts due to anthropogenic factors was estimated by marina dock space, proximity to marked boating channels, and proximity to a major highway. Redundancy analyses and variance partitioning were utilised to quantify the relative influence of local habitat structure, landscape configuration, and anthropogenic pressures on the distribution of 18 odonate species. Our results show that local habitat structure, landscape configuration, and boating pressures influence odonate community composition. Overall variance in the species composition explained was 36.5% for adults (25.3% landscape configuration and habitat structure, 6.0% boating pressure, 5.2% shared) and 21.9% for exuviae (13.2% landscape configuration and habitat structure, 6.9% boating pressure, 1.8% shared). We found that communities of adults and larvae (sampled as exuviae) are influenced by different factors. Overall, we find evidence that odonate community composition is affected by boating pressures. This stresses the need to consider not only global‐scale human disturbances in conservation planning but also localised effects which differentially impact major life stages.