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Understanding population-level habitat requirements is important for the effective conservation of imperilled species, especially for those with fragmented distributions. This study examined fine-scale distribution of the threatened pugnose shiner (Notropis anogenus) in the upper St. Lawrence River, Ontario, Canada. Occupancy modelling, multivariate analyses, and co-occurrence modelling were used to identify environmental correlates of pugnose shiner distribution and species associations in an embayment area, Thompson's Bay. The pugnose shiner was most abundant in outer bay sites that were cooler, less turbid, had a higher pH, and had more submerged aquatic vegetation than the inner bay sites. The probability of pugnose shiner occupancy increased with distance from the inner bay and with the presence of Chara vulgaris, and decreased with increasing conductivity. The pugnose shiner positively co-occurred with seven species, including the blackchin shiner and blacknose shiner, and negatively co-occurred with bluegill. Centrarchid species were dominant across Thompson's Bay. This has important conservation implications because some native centrarchid predators are increasing in abundance, coincident with climate change, which may threaten the persistence of rare and imperilled cyprinids such as pugnose shiner. [ABSTRACT FROM AUTHOR]

Aim: We assess climate similarity among global freshwater and terrestrial ecoregions under historical and future climate scenarios to determine where climate change will impact the climate filter of invasion process. Location: Global. Methods: We used the Climatch algorithm to conduct a climate‐match analysis to quantify the climate similarity between freshwater and terrestrial ecoregions of the world. Climate match was modelled between all freshwater and terrestrial ecoregions. The analysis was conducted under historical climates and projected climates of 2081–2100 (2090) under three shared socioeconomic pathways SSP2‐4.5, SSP3‐7.0, SSP5‐8.5. Climate matches of each ecoregion were presented as mean climate match to all other ecoregions of the same set. Friedman's non‐parametric rank sum two‐way analysis of variance with repeated measures was used to examine differences in mean climate match between climate scenarios. Results: Mean climate match of ecoregions was projected to increase significantly with small effect sizes for freshwater ecoregions (recipients: 0.132; sources: 0.105), and moderate and small effect sizes for terrestrial ecoregions (recipients: 0.330; sources: 0.259). Climate change was predicted to increase mean climate match in North America and Eurasia, particularly in the Arctic by 2090 under each SSP. Ecoregions in central Africa and South America were predicted to have reduced mean climate match. Ecoregions within larger countries (e.g. Australia, Canada, USA) showed variation in mean climate match. Main Conclusion: Climate change projections of bioclimatic predictors of species invasions were shown to increase in homogeneity under higher emissions scenarios. Furthermore, we demonstrate how climate change will provide opportunities for invasive species transported among ecoregions to survive under new conditions and identify where the climate filter of the invasion process will be most affected. Findings can be used to inform conservation actions for mitigating the impacts of introduced species by identifying potential risky source regions of future freshwater and terrestrial invasions under climate change. [ABSTRACT FROM AUTHOR]

Biodiversity loss is a serious issue for freshwater fishes in temperate climates and there is a need for more information in this area. A study was conducted to assess fish community changes in the littoral zone of 22 lakes over a 45 year period (compared years 1969-1979 and year 2014). To compare fish communities, historical seining records were compiled for 22 inland lakes and compared with contemporary data sampled using the same protocol. Fish abundance data analyzed using a multivariate approach identified a shift from cyprinid-dominated communities to centrarchid-dominated communities between time periods. There was no evidence to support a strong influence of invasive species on these communities, but there have been significant changes in temperature and land use around these lakes since the historical data sets were collected. This is an important contribution to our understanding of biodiversity change in North American freshwater fish communities and may influence fisheries management approaches in the future. [ABSTRACT FROM AUTHOR]

Aim: We employed a climate‐matching method to evaluate potential source regions of freshwater invasive species to an introduced region and their potential secondary spread under historical and future climates. Location: Global source regions, with primary introductions to the Laurentian Great Lakes and secondary introductions throughout North America. Methods: We conducted a climate‐match analysis using the CLIMATE algorithm to estimate global source freshwater ecoregions under historical and future climates with an ensemble of global climate models for climate‐change scenario SSP5‐8.5. Given existing research, we use a climate match of ≥71.7% between ecoregions to indicate climatic conditions that will not inhibit the survival of introduced freshwater organisms. Further, we estimate the secondary spread of freshwater invaders to the ecoregions of North America under historical and future climates. Results: We identified 54 global freshwater ecoregions with a climate match ≥71.7% to the recipient Laurentian Great Lakes under historical climatic conditions, and 11 additional ecoregions were predicted to exceed the threshold under climate change. Three of the 11 ecoregions were located in South America, a continent where no matches existed under historical climates and eight were located in the southern United States, southern Europe, Japan and New Zealand. Further, we identify 34 North American ecoregions of potential secondary spread of freshwater invasions from the Great Lakes under historical climatic conditions, and five ecoregions were predicted to exceed the threshold under climate change. Main Conclusion: We provide a climate‐match method that can be employed to assess the sources and spread of freshwater invasions under historical and future climate scenarios. Our climate‐match method predicted increases in climate match between the recipient region and several potential source regions, and changes in areas of potential spread under climate change. The identified ecoregions are candidates for detailed biosecurity risk assessments and related management actions. [ABSTRACT FROM AUTHOR]

Climate change will ultimately affect the supply and quality of freshwater lakes and rivers throughout the world. This study examines the potential impacts of climate change on freshwater fish distributions in Canada. Climate normals data (means from 1961 to 1990) from Environment Canada were used to map current climate found throughout the tertiary watersheds of Canada. Logistic regressions based on these climate data were used to develop predictive presence-absence equations for (a) common commercially and recreationally important species and (b) an Arctic freshwater species and a freshwater fish species of conservation significance listed by the Committee on the Status of Endangered Wildlife (COSEWIC). The Canadian Centre for Climate Modelling and Analysis Global Coupled Model 2(IS92a) provided forecasts of Canada's climate in 2020 and 2050. The data from this scenario and the logistic regressions provided a ready framework for predicting the potential distributions of the fishes. Physical and ecological barriers would have to be overcome for the distribution of these species to actually change in response to climate change. Generally, coldwater species may be extirpated from much of their present range while cool and warm-water species may expand northward. Species that are limited to the most southern regions of the country may expand northwards. A conceptual framework for assessing potential climate change impacts on fishes and the variety of management strategies required to deal with these impacts are discussed. Our forecasts demonstrate the need for climate change assessments in species at risk as well as for common species. [ABSTRACT FROM AUTHOR]

Aim: Here, we use an integrative, comprehensive risk assessment framework as a screening tool to evaluate how the invasion risk of previously failed introduced freshwater fish species, commonly found in the live‐trade pathway, will change under future climate‐change scenarios. Location: Laurentian Great Lakes, North America. Methods: The 34 species screened for invasion risk previously failed to establish populations, likely due to poor environmental suitability, low propagule pressure, and/or biotic resistance from the recipient community, and are most commonly found in the increasingly important live‐trade pathway. Using established trait‐based models, we quantified the probability of establishment success and probability of having high ecological impact in the decade of first introduction and present‐day communities (2020) based on known species extirpations, introductions and establishments between 1870 and 2020. We completed a climate match analysis under future climate‐change scenarios based on 16 bioclimatic variables. This approach identified a list of species that should be prioritized in surveillance management. Results: We identified seven species that have an increased climate match with the region and an increased probability of establishment success. Five of these species have an increased probability of high ecological impacts. Twenty‐four species have a current probability of establishment success greater than 50% and 33 species have a current probability of high ecological impacts greater than 50%. Climate match was dynamic under future climate‐change scenarios with 14 species experiencing a better match between their native geographical range and the Laurentian Great Lakes region. Main conclusions: Our models identify and predict the invasion risk of non‐native freshwater fish species present in pathways relevant to the Great Lakes region and provide a comprehensive framework for future management that prioritize efforts to species of highest risk. This framework could be applied to different taxa, pathways, and/or ecosystems to estimate current and predicted invasion risk under multiple scenarios. [ABSTRACT FROM AUTHOR]

Despite the promising applications of genome-wide information to conservation, the field of conservation genomics remains hindered by a research-practice gap. Identifying the benefits from genomics in relation to fish conservation planning and decision-making could contribute to bridging this gap. The goals of our study were twofold. First, we reviewed the fish conservation genomic literature to determine how genomic information has been used to inform conservation decision making; and second, we examined how genomic information can be linked to an existing conservation decision framework. Our review showed that, as fish conservation genomics studies accumulate over time, collaborations between researchers and conservation practitioners are becoming increasingly frequent. While the field is dominated by studies of economically important families (e.g. salmonids, acipenserids) in first-world countries (North America, Europe), it has a broad taxonomic coverage where species of both local and global conservation concern are well represented. We also show that genomic information can readily be harnessed to guide decisions within existing conservation decision frameworks, from the conceptualization (identification of conservation targets and threats) to the implementation and the monitoring of conservation actions. In addition, our review identifies some limitations related to genomic inferences for conservation and proposes solutions to address these uncertainties and improve communication between conservation genomic scientists and practitioners. For genomic researchers, we outline how conservation decisions are made; for practitioners, we illustrate how genomic information can inform decision-making. [ABSTRACT FROM AUTHOR]

The availability of suitable thermal habitat for fishes in streams is influenced by several factors, including flow, channel morphology, riparian vegetation, and land use. This study examined the influence of air temperature and groundwater discharge, predictors of stream temperature, on the thermal diversity (cold-, cool-, and warm-water preferences) of stream fish communities in southern Ontario watersheds. Site-level fish sampling data were used to assess the thermal diversity of 43 quaternary watersheds using three metrics, the proportion of sites within a watershed having (i) cold-, (ii) cool-, and (iii) warm-water fishes. Our results indicated that 53.9% of the variances in cold-water and 54.1% of the variances in warm-water fish distributions within the watersheds could be attributed to groundwater discharge and air temperature variables. Climate change scenarios suggested that watersheds with high groundwater discharge and the associated thermal diversity of fishes within those watersheds are less sensitive to climate change than watersheds with low groundwater discharge. Conservation of groundwater resources will be required to lessen climate change impacts on the thermal habitat and thermal diversity of stream fishes in southern Ontario watersheds. [ABSTRACT FROM AUTHOR]

Background: The winter tick (Dermacentor albipictus) has garnered significant attention throughout North America for its impact on wildlife health, and especially for moose (Alces alces), where high tick burdens may result in host hair loss, anemia, and can prove fatal. The environmental transmission of D. albipictus larvae to a host is a critical event that has direct impact on infestation success, yet in-field observations of this life stage are lacking. In Yukon, Canada, D. albipictus had previously been found on hosts, but its larval life stage had not been detected in the field, despite previous sampling attempts. Methods: We sampled for D. albipictus larvae using traditional flagging methods in Ibex Valley and Braeburn, Yukon. Sites were sampled repeatedly for D. albipictus larvae by flagging from late August to end of October in 2018 and late August to end of November 2019. Results: Larvae of D. albipictus were collected throughout Ibex Valley, at approximate densities ranging from 0.04 to 4236 larvae/100 m2. Larvae were present primarily on grassy vegetation on south-facing slopes in the Ibex Valley region and in Braeburn. Highest average larval numbers suggest peak questing activity was towards the end of September and beginning of October, as elsewhere in North America. Conclusions: To the best of our knowledge, we report the first successful collection of the off-host, larval life stage of D. albipictus by flagging, north of 60° latitude in Yukon, Canada. These new observations provide critical information on the spatial distribution of the host-seeking life stage of D. albipictus and confirm that this species is completing its whole life cycle in southern Yukon. Understanding the environmental conditions where larvae spend their vulnerable period off-host in this northern location can inform both management strategies and projections of future range expansion which may occur with a changing climate. [ABSTRACT FROM AUTHOR]