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A globally invasive fish, Eurasian tench (Tinca tinca) is spreading through the St. Lawrence River and poses an imminent invasion threat to the Great Lakes. Following its illegal release into a tributary of the St. Lawrence River in 1991, tench has spread throughout the river's main stem over the past decade, and its abundance in commercial fishing bycatch in the river has grown exponentially. The tench is a generalist benthic consumer with largely undocumented ecological impacts in North America. Reports from other invaded regions indicate that it can compete with other benthic fishes, host a diverse assemblage of parasites and pathogens, degrade water clarity in shallow lakes, limit submerged macrophyte growth, reduce gastropod populations, and promote benthic algal growth through top-down effects. Risk assessments and climate-match models indicate that the Great Lakes are vulnerable to tench invasion, and they signal the need for timely comprehensive actions, including development and implementation of monitoring and rapid-response protocols, including prevention or slowing of natural dispersal through canals. La tanche (Tinca tinca), un poisson envahissant a l'echelle planetaire, se propage dans le fleuve Saint-Laurent et presente une menace imminente d'envahissement pour les Grands Lacs. Dans la foulee de son lacher illegal dans un affluent du Saint-Laurent en 1991, la tanche s'est repandue a la grandeur du bras principal du fleuve au cours de la derniere decennie, et son abondance dans les prises accessoires de peches commerciales a connu une augmentation exponentielle. La tanche est un consommateur benthique generaliste dont les impacts ecologiques en Amerique du Nord demeurent largement non documentes. Des rapports provenant d'autres regions envahies indiquent qu'elle peut faire concurrence a d'autres poissons benthiques, est l'hote d'un assemblage varie de parasites et de pathogenes, cause la deterioration de la clarte de l'eau dans les lacs peu profonds, limite la croissance des macrophytes submerges, reduit les populations de gasteropodes et favorise la croissance d'algues benthiques par le biais d'effets descendants. Les evaluations du risque et les modeles climatiques indiquent que les Grands Lacs sont vulnerables a l'envahissement par la tanche et font ressortir la necessite de mettre rapidement en place des mesures exhaustives, dont l'elaboration et l'application de protocoles de surveillance et d'intervention rapide incluant la prevention ou le ralentissement de la dispersion naturelle a travers les canaux. [Traduit par la Redaction], Introduction The Great Lakes have been invaded by at least 188 non-native species (Ricciardi 2006; A. Ricciardi, unpublished data), including 28 fishes (Mandrak and Cudmore 2010). These introductions have affected [...]

A better understanding of how human activities affect biodiversity can be important for effective resource management. We tested how excavation (maintenance) of agricultural drains (ditches) altered fish assemblages. Uncertainty regarding the effects of drain maintenance on fish assemblages has been a source of tension between landowners, drain superintendents, and fishery managers. Fish assemblages in eight southwestern Ontario drains were sampled repeatedly from before to 2 years after drain maintenance using a replicated before-after, control-impact (BACI) design. Relative to reference sites, we found no evidence for short- or long-term decreases in the number of species and total abundance of fishes following drain maintenance, nor any consistent change in assemblage composition, despite clear changes in physical habitat. The fish assemblages in drains were resilient to drain maintenance and did not show changes expected to concern fishery managers. Our findings provide fishery managers with the information needed to manage drain maintenance more effectively under the Fish Protection Program of the Fisheries Act and to develop drain maintenance practices that balance the needs of agriculture with the protection of fish biodiversity. Une meilleure comprehension de l'incidence de l'activite humaine sur la biodiversite peut etre importante pour une gestion efficace des ressources. Nous avons verifie comment l'excavation (entretien) de drains agricoles (fosses) modifie les assemblages de poissons. L'incertitude quant aux effets de l'entretien des drains sur les assemblages de poissons constitue une source de tension entre les proprietaries fonciers, les gestionnaires des drains et les gestionnaires des peches. Les assemblages de poissons dans huit drains du sud de l'Ontario ont ete echantillonnes a repetition avant leur entretien et jusqu'a deux ans apres ce dernier selon un schema avant-apres, temoin-intervention (<>). Par rapport aux emplacements de reference, nous n'avons observe aucun indice de baisse a court ou long terme du nombre d'especes ou de l'abondance totale de poissons apres l'entretien des drains, ni aucun changement coherent de la composition des assemblages, malgre des modifications tres nettes de l'habitat physique. Les assemblages de poissons dans les drains etaient resilients a l'entretien de ces derniers et ne presentaient pas de changements susceptibles de preoccuper les gestionnaires des peches. Nos constatations fournissent a ces derniers des renseignements necessaries pour gerer l'entretien des drains plus efficacement dans le cadre du programme de protection des poissons de la Loi sur les peches et pour elaborer des pratiques d'entretien des drains qui visent un equilibre entre les besoins des agriculteurs et la protection de la biodiversite de poissons. [Traduit par la Redaction], Introduction Scientists are being pressed to provide information on the ability of ecosystems to resist and recover from change caused by human actions. Truly wild ecosystems are largely nonexistent, and [...]

Detection of invasive species is critical for management but is often limited by challenges associated with capture, processing and identification of early life stages. DNA metabarcoding facilitates large‐scale monitoring projects to detect establishment early. Here, we test the use of DNA metabarcoding to monitor invasive species by sequencing over 5000 fishes in bulk ichthyoplankton samples (larvae and eggs) from four rivers of ecological and cultural importance in southern Canada. We were successful in detecting species known from each river and three invasive species in two of the four rivers. This includes the first detection of early life‐stage rudd in the Credit River. We evaluated whether sampling gear affected the detection of invasive species and estimates of species richness, and found that light traps outperform bongo nets in both cases. We also found that the primers used for the amplification of target sequences and the number of sequencing reads generated per sample affect the consistency of species detections. However, these factors have less impact on detections and species richness estimates than the number of samples collected and analysed. Our analyses also show that incomplete reference databases can result in incorrectly attributing DNA sequences to invasive species. Overall, we conclude that DNA metabarcoding is an efficient tool for monitoring the early establishment of invasive species by detecting evidence of reproduction but requires careful consideration of sampling design and the primers used to amplify, sequence and classify the diversity of native and potentially invasive species. [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]

Predicting how quickly populations expand their range and whether they will retain genetic diversity when they are introduced to new regions or track environmental conditions suited to their survival is an important applied and theoretical challenge. The literature suggests that long‐distance dispersal, landscape heterogeneity and the evolution of dispersal influence populations' expansion rates and genetic diversity. We used individual‐based spatially explicit simulations to examine these relationships for Tench (Tinca tinca), an invasive fish expanding its geographical range in eastern North America since the 1990s. Simulated populations varied greatly in expansion rates (1.1–28.6 patches year−1) and genetic diversity metrics, including changes in observed heterozygosity (−19 to +0.8%) and effective number of alleles (−0.32 to −0.01). Populations with greater dispersal distances expanded faster than those with smaller dispersal distances but exhibited considerable variation in expansion rate among local populations, implying less predictable expansions. However, they tended to retain genetic diversity as they expanded, suggesting more predictable evolutionary trajectories. In contrast, populations with smaller dispersal distances spread predictably more slowly but exhibited more variability among local populations in genetic diversity losses. Consistent with empirical data, populations spreading in a longer, narrower dispersal corridor lost more neutral genetic variation to the stochastic fixation of alleles. Given the unprecedented pace of anthropogenic environmental change and the increasing need to manage range‐expanding populations, our results have conservation ramifications as they imply that the evolutionary trajectories of populations characterised by shorter dispersal distances spreading in narrower landscapes are more variable and, therefore, less predictable. [ABSTRACT FROM AUTHOR]

Wetlands are increasingly in peril as a result of human activities. In the Laurentian Great Lakes, coastal wetlands provide essential habitats for many fishes. Consequently, efficient sampling approaches for wetland fishes are needed for effective management. We employed a repeat-sampling strategy using a seine to collect fishes from seven wetlands. The data set was used to develop guidance for optimizing wetland fish sampling. To meet richness targets, the required number of sampling sites decreases as sampling intensity increases. Half the number of sites was required when three seine hauls per site were done compared with one haul. On average, 97 one-haul sites were required to detect 90% of species, whereas only 47 three-haul sites were required. Sampling effort is predicted to be greater in areas with more species and larger wetlands. The number of individuals and sites needed to detect 90% of species increased exponentially as species richness increased, and the number of individuals needed was positively related to wetland area. The use of block nets did not improve species detection or affect the composition. Les milieux humides sont de plus en plus menaces en raison de l'activite humaine. Dans les Grands Lacs laurentiens, les milieux humides littoraux fournissent des habitats essentiels pour de nombreux poissons. Par consequent, des approches d'echantillonnage efficientes des poissons de milieux humides sont necessaires pour en assurer une gestion efficace. Nous avons employe une strategie d'echantillonnage repete a l'aide d'une seine pour prelever des poissons de sept milieux humides. L'ensemble de donnees a ete utilise pour formuler des conseils pour optimiser l'echantillonnage des poissons de milieux humides. Pour atteindre la richesse visee, plus l'intensite de l'echantillonnage est forte, plus le nombre requis de sites d'echantillonnage est faible; moitie moins de sites etaient requis quand trois traits de seine etaient realises par site plutot qu'un seul. En moyenne, 97 sites a un trait etaient necessaires pour detecter 90 % des especes, comparativement a seulement 47 sites a trois traits. Il est predit que l'effort d'echantillonnage doit etre plus grand dans les zones comptant plus d'especes et des milieux humides plus grands. Le nombre d'individus et de sites necessaires pour detecter 90 % des especes augmentait de maniere exponentielle quand la richesse specifique augmentait, et le nombre d'individus necessaires etait positivement relie a la superficie des milieux humides. L'utilisation de filets d'isolement n'ameliorait pas la detection d'especes ni n'avait d'incidence sur leur composition. [Traduit par la Redaction], Introduction Wetlands are valuable ecosystems because of provisions and services that they provide for humans, such as flood control, purifying and storing water, groundwater discharge, carbon sequestration, and recreational opportunities [...]

Abstract: Although electrosedation is becoming a frequently used technique to anaesthetize fish for a variety of commercial, management, and research applications, limited information is available on the effectiveness of different [...]

Changes in resource development and expansions of urban centres suggest that the intensity and types of anthropogenic stressors affecting Canada's watersheds are changing. Chu et al. (2003) integrated indices of freshwater fish biodiversity, environmental conditions, and anthropogenic stress to identify priority watersheds for conservation and management. Here, we update those indices using recent climate and census data to assess changes through time. We also applied different conservation and management scenarios to evaluate the robustness of our prioritization approach. Between time periods, the environmental and stress indices expanded northward because of warmer temperatures at higher latitudes and more intense anthropogenic stress in the northern regions of the provinces. Conservation priorities increased in northern British Columbia, Alberta, and Ontario but decreased in southern British Columbia, Saskatchewan, and south-central Quebec. Under multiple scenarios, conservation priorities were consistently highest in British Columbia, the Maritimes, southern Ontario, and southern Quebec. Future research to refine this assessment should focus on developing a nationwide georeferenced assessment of freshwater fisheries stress, quantifying spatial changes in the stressors, and evaluating the sensitivity of each index to the weighting of the individual variables. This work highlights the necessity for conservation and management strategies in Canada to keep pace with changing patterns in climate and human activities. Les changements a l'exploitation des ressources et l'expansion des centres urbains devraient modifier l'intensite et les types de facteurs de stress d'origine humaine agissant sur les bassins versants canadiens. Chu et al. (2003) ont integre des indices de biodiversite des poissons d'eau douce, de conditions ambiantes et de stress d'origine humaine afin de cerner les bassins versants prioritaires sur le plan de la conservation et de la gestion. Nous actualisons ces indices a la lumiere de donnees climatiques et de recensement recentes afin d'evaluer les changements au fil du temps. Nous appliquons egalement differents scenarios de conservation et de gestion dans le but d'evaluer la robustesse de notre approche de priorisation. D'une periode a l'autre, les indices de conditions ambiantes et de stress se sont propages vers le nord en raison du rechauffement a hautes latitudes et de l'intensification des stress d'origine humaine dans les regions nordiques des provinces. Les priorites de conservation ont augmente dans le nord de la Colombie-Britannique, en Alberta et en Ontario, mais diminue dans le sud de la Colombie-Britannique, en Saskatchewan et dans le centre-sud du Quebec. Pour plusieurs scenarios, les priorites de conservation etaient uniformement les plus elevees en Colombie-Britannique, dans les Maritimes et dans le sud de l'Ontario et du Quebec. La recherche future visant a raffiner cette evaluation devrait mettre l'accent sur l'etablissement d'une evaluation pancanadienne georeferencee des stress sur les ressources halieutiques d'eau douce, la quantification de l'evolution spatiale des facteurs de stress et l'evaluation de la sensibilite de chaque indice a la ponderation des differentes variables. Ces travaux soulignent le fait que les strategies de conservation et de gestion au Canada devront s'adapter aux motifs changeants du climat et de l'activite humaine. [Traduit par la Redaction], Introduction Fish communities within freshwater ecosystems are shaped by continental-scale patterns, such as glaciation and recolonization, and local patterns, such as lake morphometry, water quality, and biotic interactions (Tonn 1990; [...]

Freshwater turtle populations are declining globally as a result of anthropogenic activities. Threats to turtles in urban areas are exacerbated by road mortality and subsidized predators, which can lead to catastrophic shifts in population size and structure. Headstarting is used as a conservation tool to supplement turtle populations that may otherwise face extirpation. A headstarting program began in 2012 to recover a functionally extinct population of Blanding's Turtles (Emydoidea blandingii) 26in Rouge National Urban Park (RNUP), Ontario, Canada. The original population included five adults and one juvenile turtle. From 2014 to 2020, 270 headstarted turtles were released. The population has been monitored annually since 2014 using visual-encounter surveys, radio-telemetry, and live trapping (from 2018 onwards). We used mark-recapture and radio-telemetry data to quantify abundance, survival, and sex ratio of the headstarted turtle population. Using a Jolly-Seber model, we estimated abundance to be 183 turtles (20 turtles/ha) in 2020. Estimated survival of headstarted turtles approached 89%, except for turtles released in 2019 when survival was 43% as a result of a known mass mortality event at the study site. Pre- and post-release sex ratios were not significantly different (χ2 = 1.92; p = 0.16), but shifted from 1:1.5 to 1:1 male:female post-release. Given that the headstarted turtles have not yet reached sexual maturity, it is unclear whether headstarted turtles will reach adulthood and successfully reproduce to maintain a self-sustaining population. Thus, to evaluate the success of the headstarting program, long-term monitoring is required. [ABSTRACT FROM AUTHOR]

Aim: Biological communities are the result of a stepwise spatiotemporal filtering process, driven by large‐scale historical and local contemporary determinants. The biogeographical pattern and species richness of North American fishes are predominantly determined by historical processes of past glaciations and postglacial dispersal and by contemporary environmental and ecological processes. We evaluated the effects of postglacial dispersal through glacial Lake Agassiz and habitat heterogeneity, represented by lake surface area, on contemporary freshwater fish species richness patterns of northwestern Ontario lakes. Location: Northwestern Ontario, Canada. Taxon: Freshwater fishes. Methods: Applying the theory of island biogeography and species–area curves, we examined the effects of isolation from the past dispersal corridor of glacial Lake Agassiz and habitat heterogeneity on species richness across 264 contemporary lakes. While controlling for correlations among the predictor variables, generalized linear models were constructed between species richness, as the response variable and the explanatory variables of lake elevation and surface area, and connection to the dispersal corridor. Results: Differential cover by glacial Lake Agassiz led to variation in fish species richness across contemporary lakes and it is higher in lakes that were covered by Lake Agassiz relative to basins remaining outside of the boundaries of the glacial lake. Lake surface area is the strongest predictor of species richness, while lake elevation is the strongest factor predicting isolation. Main Conclusions: Habitat heterogeneity and postglacial colonization have led to differences in fish richness within the same geographical region, which increases with lake surface area and decreases with elevation. These are likely driven by greater niche diversity facilitating the assembly of more diverse communities and isostatic rebound and fluctuating levels of Lake Agassiz isolating lakes at high elevations from the dispersal route earlier during the colonization process, respectively. These patterns underscore the importance of incorporating historical and environmental community determinants in biodiversity studies. [ABSTRACT FROM AUTHOR]

Concerns that climate warming may drive the spread of ectoparasites into previously uninhabited areas have increased the need for baseline knowledge of their distributional history. For species of wildlife health concern, presence data are often lacking or outdated, thus limiting our ability to assess range changes and subsequent host impacts. We reconstructed the past and present distribution of the winter tick, Dermacentor albipictus, through the compilation of a spatiotemporal database to create the first full baseline map of its occurrence throughout its North American range. The ongoing impacts of winter tick epizootics in moose (Alces alces) and recent mortality events in elk (Cervus canadensis) and white‐tailed deer (Odocoileus virginianus) have led to a resurgence in interest in the future of this parasite in a warming climate. Over 3400 unique records of winter tick occurrence were compiled from multiple data sources, dating from 1869 to 2020 and spanning from 16.5 to 66.2° N latitude. Both conventional published sources and natural history records were included along with new records from previously unpublished datasets and citizen science observations, to make this a comprehensive occurrence dataset for this species. Along with standardized location information and year of observation, the dataset includes associated host species and descriptive categorization of the type and source of each record, providing new opportunities to examine host–parasite interactions in the winter tick system over time and space. In presenting these data, we discuss the potential sampling biases and lacunas in our integrated database records, particularly at the winter tick's northernmost range. We also document changes in the types and sources of winter tick information from past to present, highlighting potential issues that should be considered before using these data in further analyses and when collecting ongoing records. Our database demonstrates that the collation and synthesis of records beyond conventional sources can shed light on the distributional history of tick species and serve as a useful baseline for prioritizing future research and management decisions. [ABSTRACT FROM AUTHOR]

Introduced and geographically expanding populations experience similar eco‐evolutionary challenges, including founder events, genetic bottlenecks, and novel environments. Theory predicts that reduced genetic diversity resulting from such phenomena limits the success of introduced populations. Using 1900 SNPs obtained from restriction‐site‐associated DNA sequencing, we evaluated hypotheses related to the invasion history and connectivity of an invasive population of Tench (Tinca tinca), a Eurasian freshwater fish that has been expanding geographically in eastern North America for three decades. Consistent with the reported history of a single introduction event, our findings suggest that multiple introductions from distinct genetic sources are unlikely as Tench had a small effective population size (~114 [95% CI = 106–123] individuals), no strong population subdivision across time and space, and evidence of a recent genetic bottleneck. The large genetic neighbourhood size (220 km) and weak within‐population genetic substructure suggested high connectivity across the invaded range, despite the relatively large area occupied. There was some evidence for a small decay in genetic diversity as the species expanded northward, but not southward, into new habitats. As eradicating the species within a ~112 km radius would be necessary to prevent recolonization, eradicating Tench is likely not feasible at watershed—and possibly local—scales. Management should instead focus on reducing abundance in priority conservation areas to mitigate adverse impacts. Our study indicates that introduced populations can thrive and exhibit relatively high levels of genetic diversity despite severe bottlenecks (<1.5% of the ancestral effective population size) and suggests that landscape heterogeneity and population demographics can generate variability in spatial patterns of genetic diversity within a single range expansion. [ABSTRACT FROM AUTHOR]

Invasive species denialism (ISD) is a controversial and hitherto underexplored topic, particularly with regard to its potential impacts on stakeholder engagement in support of invasive species management and policy. We examined how ISD is framed within the Great Lakes invasive species community, as well as the impacts of excluding and including those perceived as denialists in engagement efforts. We interviewed key informants in the region to gain an understanding of their framings of ISD, as well as focus groups allowing participants to discuss the impacts of exclusion and inclusion of stakeholders during the engagement process. ISD discussions were organised into three framings: 1) invasive species denialism; 2) invasive species cynicism; 3) invasive species nihilism. Participants raised concerns about outright exclusion of stakeholders and offered recommendations for mitigation of the impacts of inclusion of proponents of ISD in during stakeholder engagement. Our results have shown that a better understanding of the different framings of ISD is crucial to improve communication with stakeholders and to better inform responses and mitigation efforts. The newly defined framings of invasive species cynicism and invasive species nihilism demonstrate that more targeted responses to specific forms of ISD are needed to improve stakeholder engagement outcomes. [ABSTRACT FROM AUTHOR]

Simple Summary: Surveying ticks on wildlife hosts consistently over time and across space presents many challenges. In Yukon, Canada, the winter tick, Dermacentor albipictus, is a blood-feeding parasite that can cause significant losses of hair and blood in moose and other wildlife. The impacts of winter tick infestation in wildlife hosts in this northern region are not well documented. To enhance existing surveillance of winter ticks in Yukon, we implemented a three-year citizen science program, the Yukon Winter Tick Monitoring Project (YWTMP) to engage hunters in the collection of underrepresented moose and caribou samples. Social media, participation incentives, and hide-sampling kits distributed to hunters increased the combined number of annual moose and caribou hide submissions almost 100-fold, and the geographical range of samples by almost 500 km, compared with submission numbers in the previous seven years. Citizen science samples were also used to detect previously unknown infection localities on moose in southeastern Yukon that are spatially separate to known infestations found on elk and deer, helping to build a better picture of infection dynamics on different host animals. Engaging with key demographic groups using structured citizen science programs like the YWTMP can significantly expand sampling efforts in remote areas while maintaining systematic sampling methods to monitor parasites of wildlife health concern. Sampling hides from harvested animals is commonly used for passive monitoring of ectoparasites on wildlife hosts, but often relies heavily on community engagement to obtain spatially and temporally consistent samples. Surveillance of winter ticks (Dermacentor albipictus) on moose (Alces alces) and caribou (Rangifer tarandus caribou) hosts in Yukon, Canada, has relied in part on voluntary submission of hides by hunters since 2011, but few samples were submitted. To enhance sampling efforts on underrepresented moose and caribou hosts, we implemented a three-year citizen science program, the Yukon Winter Tick Monitoring Project (YWTMP), to better engage with hunters in hide sample collection. A combination of in-person and social media outreach, incentivized engagement, and standardized hide sampling kits increased voluntary submissions of moose and caribou hides almost 100-fold since surveillance began. Citizen science samples expanded the northernmost geographic extent of existing sampling efforts for moose by 480 km and for caribou by 650 km to reach 67.5° N latitude. Samples also resulted in new detections of winter ticks on moose hides that are spatially separate to those submitted for other cervids in Yukon. Findings from the YWTMP have provided an essential baseline to monitor future winter tick host–parasite dynamics in the region and highlighted priority areas for ongoing tick surveillance. [ABSTRACT FROM AUTHOR]

Science-based approaches for selecting among single-species, community-, and ecosystem-based recovery plans are needed to conserve imperilled species. Selection of recovery plans has often been based on past success rates with other taxa and systems or on economic cost, but less on the ecology of the system in question. We developed a framework for selecting a recovery plan based on the distributions and ecology of imperilled and nonimperilled species across available habitat types and applied it to fishes in the Sydenham River, Ontario, Canada. We first tested whether distributions of fishes were adequately predicted by habitat features hypothesized to limit the distributions of imperilled fishes versus a broader set of habitat features known to predict fish distributions. We then tested whether imperilled species occurred in similar or disparate habitat types. For the Sydenham River, an ecosystem-based recovery plan was deemed most appropriate because imperilled species occur in disparate habitat types. We lastly provide decision criteria to facilitate applications of our framework to the selection of recovery plans for other species and systems. Afin d'assurer la conservation des especes en peril, il est necessaire de posseder des methodes basees sur la science pour choisir entre les plans de recuperation centres sur une seule espece, sur une communaute ou sur un ecosysteme. Le choix d'un plan de recuperation se base souvent plus sur les taux de succes obtenus avec d'autres taxons et dans d'autres systemes ou sur le cout economique, mais moins sur l'ecologie du systeme en question. Nous avons mis au point un cadre de selection d'un plan de recuperation base sur la repartition et l'ecologie des especes menacees et non menacees dans les differents types d'habitats disponibles et nous l'avons utilise dans le cas des poissons de la riviere Sydenham, Ontario, Canada. En premier lieu, nous avons verifie si les repartitions des poissons pouvaient etre adequatement predites d'apres les caracteristiques de l'habitat que nous soupconnions limiter les repartitions des poissons menaces, par comparaison a celles obtenues a partir d'un eventail connu et plus etendu de caracteristiques de l'habitat capable de predire les repartitions de poissons. Nous avons ensuite verifie si les especes menacees se retrouvaient dans des types d'habitat similaires ou disparates. Dans la Sydenham, un plan de recuperation a l'echelle de l'ecosysteme nous semble plus approprie car les especes menacees vivent dans des types d'habitat disparates. Nous fournissons enfin des criteres de choix pour faciliter l'utilisation de notre cadre dans la selection des plans de recuperation pour d'autres especes et systemes. [Traduit par la Redaction], Introduction Science-based approaches for selecting between recovery plans are needed to protect the growing number of imperilled species listed by conservation agencies. Federal agencies in Canada, the United States, Europe, [...]

Abstract: Knowledge of Canada's lakes is needed to manage environmental stresses. Lake inventory and lake feature databases were used to build a national impact assessment template and assess regional typology. [...]

Abstract: Open agricultural drains (ditches) provide necessary drainage for cropland and may also provide habitat supporting native fish assemblages. We tested whether warm-water drains in southwestern Ontario provide fish habitat [...]

Abstract: 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 [...]

As nonindigenous species are a major threat to global biodiversity, cost-effective management requires identification of areas at high risk of establishment. Here we predict suitable environments of 14 high-profile species of nonindigenous snakehead (Channidae) and Asian carp (Cyprinidae) species in North America based upon ecological niche modelling and compare the driving environmental variables for the two fish groups. Snakeheads distributions were correlated with thermal factors, whereas those of Asian carps were related mainly to precipitation. Predicted suitable ranges for these nonindigenous species can be divided into three main areas: Mexico and the southern United Stales (five species); Mexico and the United Slates up lo ~35[degrees]N (three species); and most of Mexico, continuous United Slates, and southern Canada (six species). For the province of Ontario, we combined the number and location of aquarium stores and live fish markets with predicted areas of suitable environments to identify areas at risk of introduction and establishment. We identified several watersheds draining into northwestern Lake Ontario as having the highest risk, highlighting the increased predictive value of this approach. Comine les poissons non indigenes representent une menace importante a la biodiversite globale, une gestion efficace du point de vue des couts requiert l'identification des zones ou le risque d'etablissement est eleve. Nous predisons ici les milieux adequais pour l'etablissement de 14 especes non indigenes bien connues de pois sons-serpen is (Channidae) et de carpes asiatiques (Cyprinidae) en Amerique du Nord d'apres la modelisation ecologique des niches et nous comparons les variables du milieu qui regissent l'etablissement des deux groupes de poissons. Les repartitions des pois sons-serpents sont en correlation avec les facteurs thermiques, alors que celles des carpes asiatiques sont reliees surtout aux precipitations. Les aires adequates de repartition predites pour ces les poissons non indigenes se retrouvent dans trois regions principales: le Mexique et le sud des Etats-Unis (cinq especes), le Mexique et les Etats-Unis jusqu'a ~35[degrees]N (trois especes) et le Mexique presque dans son entier. les Etats-Unis continentaux et le sud du Canada (six especes). Pour l'Ontario, la combinaison du nombre et de Pemplacement des boutiques d'aquario phi lie et des marches de poissons vivants, d'une part, et des regions predites a habitats convenables, d'autre part, permet d'identifier les zones a risque pour les introductions et les etablissements. Nous identitions plusieurs bassins versants qui se jettent dans le nord-ouest du lac Ontario comme etant a risque tres eleve; ces resultats soulignent la valeur predictive de notre methodologie. [Traduit par la Redaction], Introduction Identifying high-risk areas for the establishment of nonindigenous species (NIS) using quantitative techniques is an important tool for the design and implementation of preventative management strategies (Leung et al. [...]

Human activity can put non‐game fishes at higher risk of extinction because of inappropriate management action. Eastern sand darter (Ammocrypta pellucida), a small benthic fish classified as threatened across much of its northern range, inhabits increasingly fragmented sandy habitats and, as a non‐game fish, may be easily overlooked in conservation efforts. In this study, the authors use genotype data from nine microsatellite loci and cytochrome oxidase I (COI) sequencing data across its northern native range to re‐assess genetic structure and to characterize a newly discovered, geographically disjunct population. Previous microsatellite marker analyses had identified seven distinct population genetic clusters across the region sampled; the analysis of this study showed that the newly discovered population (West Lake, Ontario) exhibits a divergent structure. COI haplotype analysis suggests that a single haplotype recolonized the Great Lakes and surrounding water bodies after the Wisconsinan glacial period, and subsequent fluctuation in water levels and habitat fragmentation resulted in divergence of genetic clusters. Although the novel West Lake population has a common ancestral source with other populations in the broader region, its divergent genetic signature merits its consideration as a separate conservation unit. The analyses of this study highlight the potential conservation implications of the discovery of new populations, particularly those of at‐risk species, even within a region that has been genetically well characterized. [ABSTRACT FROM AUTHOR]