Occupancy trends of overwintering coastal waterbird communities reveal guild-specific patterns of redistribution and shifting reliance on existing protected areas.

Climate change and anthropogenic stressors are redistributing species and altering community composition globally. Protected areas (PAs) may not sufficiently protect populations of species undergoing distributional shifts, necessitating that we evaluate existing PAs and identify areas for future protection to conserve biodiversity across regional and temporal scales. Coastal waterbirds are important indicators of marine ecosystem health, representing mobile, long-lived, higher trophic-level consumers. Using a 20-year citizen science dataset (1999-2019) with a before-after control-intervention sampling framework for habitat protection, we applied dynamic occupancy models to assess winter occupancy trends along the Pacific coast of Canada. Specifically, we sought to understand potential drivers of regional declines, spatial commonalities among guilds, and changes in habitat use before and after PA designation, as well as between PAs and non-PAs. Occupancy trends varied regionally, with greater declines in the south compared to the north. Regional differences underlined potential range shifts, particularly for species with traits linked to temperature tolerance, movement, and high productivity foraging, as cold-tolerant, migratory benthivores and piscivores wintered farther north relative to 20 years ago or retreated to cold-water fjords. While 21 of 57 (36.8%) species responded positively to PA designation (before-after), greater occupancy declines tended to occur in PAs established pre-1999 relative to non-PAs (control-intervention). Since PAs are currently concentrated in the south, negative associations were most apparent for species retreating northward, but existing PAs may have a stabilizing or transitory effect on southern wintering species shifting into the region from farther south. We emphasize that conservation strategies must balance persistence of current communities with preserving the climate-adapted biodiversity of tomorrow by accounting for community-level effects of species moving into and out of existing PAs. Incorporating range shifts into PA planning by predicting distributional changes will allow conservation practitioners to identify priority habitats, such as cold-water refugia, for persistent wildlife communities.

Le changement climatique et les facteurs de stress anthropiques redistribuent les espèces et modifient la composition des communautés à l'échelle mondiale. Les zones protégées (ZP) ne protègent peut-être pas suffisamment les populations d'espèces qui subissent des changements de répartition, ce qui nous oblige à évaluer les ZP existantes et à identifier les zones à protéger à l'avenir pour conserver la biodiversité à l'échelle régionale et temporelle. Les oiseaux côtiers sont des indicateurs importants de la santé des écosystèmes marins, car ils représentent des consommateurs mobiles, ont une longue durée de vie et représente le niveau trophique supérieur. En utilisant un ensemble de données de science participative sur 20 ans (1999-2019) avec un échantillonnage avant-après contrôle-intervention (AACI) pour la protection de l'habitat, nous avons appliqué des modèles d'occupation dynamiques pour évaluer les tendances de l'occupation hivernale le long de la côte pacifique du Canada. Plus précisément, nous avons cherché à comprendre les moteurs potentiels des déclins régionaux, les points communs spatiaux entre les guildes et les changements dans l'utilisation de l'habitat avant et après la désignation de le ZP, ainsi qu'entre les ZP et les non-ZP. Les tendances en matière d'occupation varient d'une région à l'autre, avec des déclins plus importants dans le sud que dans le nord. Les différences régionales soulignent les déplacements potentiels de l'aire de répartition, en particulier pour les espèces dont les caractéristiques sont liées à la tolérance à la température, aux déplacements et à la recherche de nourriture à rendement élevé, car les benthivores et les piscivores migrateurs tolérants au froid ont hiverné plus au nord qu'il y a 20 ans ou se sont retirés dans les fjords aux eaux froides. Alors que 21 des 57 (36,8 %) espèces ont réagi positivement à la désignation des aires protégées (avant-après), les baisses d'occupation ont eu tendance à être plus importantes dans les aires protégées créées avant 1999 que dans les aires non protégées (contrôle-intervention). Comme les aires protégées sont actuellement concentrées dans le sud, les associations négatives étaient plus évidentes pour les espèces qui se retirent vers le nord, mais les aires protégées existantes peuvent avoir un effet stabilisateur ou transitoire sur les espèces hivernant dans le sud qui se déplacent dans la région à partir d'une région plus au sud. Nous soulignons que les stratégies de conservation doivent trouver un équilibre entre la persistance des communautés actuelles et la préservation de la biodiversité adaptée au climat de demain, en tenant compte des effets au niveau des communautés des espèces qui entrent dans les aires protégées existantes ou qui en sortent. L'intégration des changements d'aire de répartition dans la planification des aires protégées en prédisant les changements de distribution permettra aux praticiens de la conservation d'identifier les habitats prioritaires, tels que les refuges d'eau froide, pour les communautés d'espèces sauvages persistantes.

Effects of climate on fall migration phenology of monarch butterflies departing the northeastern breeding grounds in Canada.

Monarch butterflies (Danaus plexippus) undergo an iconic multi-generational migration, traveling thousands of kilometers from the summer breeding grounds in southern Canada to overwintering sites in central Mexico. This migration phenomena can be affected by climate change, which may have important implications on fitness and ultimately populations status. We investigated the long-term trends in fall migration phenology of monarchs using a 25-year dataset collected along the coast of Lake Erie in Ontario, Canada. We also investigated local long-term trends in weather covariates that have the potential to influence migration phenology at this site. Patterns in standardized daily counts of monarchs were compared with local weather covariates using two methods (i.e., monthly averages and moving windows) to assess difference in outputs between analytical approaches. Our results suggest that monarch migration timing (migration midpoint, average peak, first peak, and late passage) and weather covariates have been consistent over time, in direct contrast to a similar study in Cape May, New Jersey, which showed a significant increase in both fall temperature and a 16- to 19-day shift in monarch migration timing. Furthermore, our results differed between analytical approaches. With respect to annual variability in air temperature, our monthly average analysis suggested that for each degree increase in September air temperature, late season passage would advance 4.71 days (±1.59 SE, p = .01). However, the moving window analysis suggested that this result is likely spurious and found no significant correlations between migration timing and any weather covariates. Importantly, our results caution against extrapolating the effects of climate change on the migration phenology of the monarch across study regions and the need for more long-term monitoring efforts to better understand regional drivers of variability in migration timing.

Spatiotemporal variation in mechanisms driving regional-scale population dynamics of a Threatened grassland bird.

To achieve national population targets for migratory birds, landscape-level conservation approaches are increasingly encouraged. However, knowledge of the mechanisms that drive spatiotemporal patterns in population dynamics are needed to inform scale-variant policy development. Using hierarchical Bayesian models and variable selection, we determined by which mechanism(s), and to what extent, changes in quantity and quality of surrogate grassland habitats contributed to regional variation in population trends of an obligatory grassland bird, Bobolink (Dolichonyx oryzivorous). We used North American Breeding Bird Survey data to develop spatially explicit models of regional population trends over 25 years across 35 agricultural census divisions in Ontario, Canada. We measured the strength of evidence for effects of land-use change on population trends over the entire study period and over five subperiods. Over the entire study period, one region (Perth) displayed strong evidence of population decline (95% CI is entirely below 0); four regions displayed strong evidence of population increase (Bruce, Simcoe, Peterborough, and Northumberland). Population trends shifted spatially among subperiods, with more extreme declines later in time (1986-1990: 28% of 35 census divisions, 1991-1995: 46%, 1996-2000: 40%, 2001-2005: 66%, 2006-2010: 82%). Important predictors of spatial patterns in Bobolink population trends over the entire study period were human development and fragmentation. However, factors inferred to drive patterns in population trends were not consistent over space and time. This result underscores that effective threat identification (both spatially and temporally) and implementation of flexible, regionally tailored policies will be critical to realize efficient conservation of Bobolink and similar at-risk species.

THE OCCURRENCE OF PATHOGENS IN AN ENDANGERED POPULATION OF AMERICAN BADGERS (TAXIDEA TAXUS JACKSONI) IN ONTARIO, CANADA.

American badgers ( Taxidea taxus jacksoni) at the periphery of the species' range in Ontario, Canada, are listed as endangered because of an estimated population size of <200 mature individuals. The main threats faced by this population include habitat loss and road mortality. However, on 18 November 2013, a radio-implanted badger was found nonresponsive in an agricultural field with signs consistent with canine distemper virus infection, which was subsequently confirmed. This prompted our investigation into the occurrence of pathogens in this endangered carnivore to better quantify the level of risk infectious disease poses to population persistence. We examined serum samples from nine live-trapped individuals and 27 whole badger specimens submitted for postmortem examination. We found evidence of exposure to canine distemper virus, canine parvovirus, and leptospires. However, infection associated with disease was not the leading cause of mortality. Future research into the effects of disease on kit survival and a comprehensive understanding of disease severity and spread from reservoir populations (e.g., raccoons [ Procyon lotor ] and striped skunks [ Mephitis mephitis ]) to badgers will be of particular importance to the conservation of this endangered population.

Spatial patterns of immunogenetic and neutral variation underscore the conservation value of small, isolated American badger populations.

Small and isolated populations often exhibit low genetic diversity due to drift and inbreeding, but may simultaneously harbour adaptive variation. We investigate spatial distributions of immunogenetic variation in American badger subspecies (Taxidea taxus), as a proxy for evaluating their evolutionary potential across the northern extent of the species' range. We compared genetic structure of 20 microsatellites and the major histocompatibility complex (MHC DRB exon 2) to evaluate whether small, isolated populations show low adaptive polymorphism relative to large and well-connected populations. Our results suggest that gene flow plays a prominent role in shaping MHC polymorphism across large spatial scales, while the interplay between gene flow and selection was stronger towards the northern peripheries. The similarity of MHC alleles within subspecies relative to their neutral genetic differentiation suggests that adaptive divergence among subspecies can be maintained despite ongoing gene flow along subspecies boundaries. Neutral genetic diversity was low in small relative to large populations, but MHC diversity within individuals was high in small populations. Despite reduced neutral genetic variation, small and isolated populations harbour functional variation that likely contribute to the species evolutionary potential at the northern range. Our findings suggest that conservation approaches should focus on managing adaptive variation across the species range rather than protecting subspecies per se.

Tracking animal movement by comparing trace element signatures in claws to spatial variability of elements in soils.

Biogeochemical markers in ecology have provided a useful means for indicating geographic origin and movement patterns of species on various temporal and spatial scales. We used trace element analysis to resolve spatial and habitat-specific environmental gradients in elemental distributions that could be used to infer geographic origin and habitat association in a model terrestrial carnivore: American badger (Taxidea taxus jacksoni). To accomplish this, we generated element base-maps using spatial principal component analysis, and assessed habitat-specific signatures using multivariate statistics from soil element concentrations in southwestern Ontario, Canada. Using canonical correlation analysis (CCA) we also test whether element variability in the claw keratin of a terrestrial carnivore could be explained by the chemical variability in the soils of the local environment. Results demonstrated that trace element signatures in soils vary locally with land use practices and soil texture type and broadly with the underlying geology. CCA results suggest that chemical profiles in claws can be linked to the surrounding chemical environment, providing evidence that geographic patterns in mammalian movement can be discerned on the basis of claw chemistry. From this, we conclude that geographic assignment of individuals based on element profiles in their tissues and referenced against soil elemental distributions would be coarse (at a spatial scale of 100-1000 km, depending on the chemical heterogeneity of the landscape), but could be used to assess origin of highly mobile animals or habitat association of individuals. Compared to stable isotope analysis, the assessment of trace elements can provide a much greater level of detail in backcasting animal movement pathways.