Although many local and regional variables structure fish assemblage composition, few studies have assessed the effects of aquatic connectivity on fish assemblages in wetlands. Fish and habitat surveys were conducted in 12 wetlands across the lower Great Lakes basin in the spring and fall of 2003 and 2004. Spatial and temporal connectivity were classified into four connectivity classes to evaluate the interaction between aquatic connectivity and fish assemblage structure. Sequential, nested analysis of covariance was used to model the effect of habitat area and connectivity at long- and short-term time scales on aggregate descriptors of assemblage structure (i.e., species richness, piscivore richness, abundance, and diversity). Although no species–area relationship was detected, increases in connectivity were shown to positively affect species richness and piscivore richness. A variation decomposition method indicated that a combination of aquatic connectivity, followed by environmental and area variables, was most influential in structuring fish assemblages at short-term time scales. Connectivity thus influences both the local species pool present, as well as the abundance of these species within a wetland. Future fundamental and applied studies (e.g., climate change predictions, impact of humans on water budget, wetland management) on wetland fish assemblages should include connectivity as an important structuring process.

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Abstract:The River Darter (Percina shumardi) is a native, rarely sampled fish that has been detected in relatively small numbers since the 1930s. It has a wide North American distribution, but little is known about the species biology and distribution across the Canadian portion of its range. We revisited many historic sampling locations and sampled additional areas to (i) confirm and update the distribution of River Darters in Canadian waters; (ii) assess relative abundance; (iii) update life history characteristics; (iv) collect diet information; and (v) identify characteristics of River Darter habitat. Since 1990, a total of 1032 River Darters were recorded from 29 waterbodies across three ecoregions. River Darters were observed in relatively high abundances in both the Saskatchewan-Nelson River and Southern Hudson Bay-James Bay ecoregions. While still extant in the Great Lakes-Upper St. Lawrence ecoregion, River Darters persist at low abundance. Life history analyses indicate similar maximum age (age 4) and growth (10 mm/year) to conspecific populations in the United States, while sex ratios are generally skewed towards female dominance. River Darter populations had high flexibility in habitat use and diet, using a range of flows and depths and a variety of seasonally available prey types.

David Lloyd George Noakes (1942–2020) is best known for his insatiable curiosity, his quick wit and dry sense of humor, his scientific contributions to the field of animal behaviour, and his ability to form and maintain long-lasting connections. His research interests were vast but remained grounded in early life history, behaviour, social behaviour, the evolution of behaviour, behavioural genetics, and evolutionary ecology. David had a remarkable ability to establish and maintain strong connections within the international academic community. David was also internationally recognized for his numerous contributions as a scientific editor, promoting accessibility to the international community that he served. We memorialize David’s legacy in this tribute article, ensuring that his accomplishments and the momentous impact he had on the scientific community are not soon forgotten.