Susan Cc Gordon

Climate change may introduce conditions beyond species’ tolerances; to survive, species must avoid these extremes. Phenological shifts are one strategy, as species move their activity or life-history events in time to avoid extreme conditions. Species may also shift in space, moving their ranges poleward to escape extremes. However, whether species are more likely to exhibit one or both strategies, and whether this can be predicted based on a species’ functional traits, is unknown. Using a powerful macroecological dataset of European and North American odonate observations, we assessed range and phenology shifts between two time periods (1980–2002 and 2008–2018) to measure the strength and direction of the association between responses. Species with the greatest poleward range shifts also showed the largest phenological shifts toward earlier annual activity periods, with half of all species shifting in both space and time. This response was consistent across continents, despite highly divergent land use and biogeographical histories in these regions. Surprisingly, species’ range and phenology shifts were not related to functional traits; rather, southern species shifted their range limits more strongly, while increasing temperature variability hindered range shifts. By reducing risk through phenological shifts, the resulting larger populations may be more likely to disperse and expand species’ ranges. Species shifting in both space and time may be more resilient to extreme conditions, although further work integrating abundance data is needed. We also identified a small number of species (approximately 10%) that failed to shift at all; these species are likely to be particularly vulnerable to climate change and should be prioritized for conservation intervention.

Climate change may introduce conditions beyond species’ tolerances; to survive, species must avoid these extremes. Phenological shifts are one strategy, as species move their activity or life history events in time to avoid extreme conditions. Species may also shift in space, moving their ranges poleward to escape extremes. However, whether species are more likely to exhibit one or both strategies, and whether this can be predicted based on a species’ functional traits, is unknown. Using a powerful macroecological dataset of European and North American odonate observations, we assessed range and phenology shifts between two time periods (1980-2002 and 2008-2018) to measure the strength and direction of the association between responses. Species with the greatest poleward range shifts also showed the largest phenological shifts toward earlier annual activity periods, with half of all species shifting in both space and time. This response was consistent across continents, despite highly divergent land use and biogeographical histories in these regions. Surprisingly, species’ range and phenology shifts were not related to functional traits; rather, southern species shifted their range limits more strongly, while increasing temperature variability hindered range shifts. By reducing risk through phenological shifts, the resulting larger populations may be more likely to disperse and expand species’ ranges. Species shifting in both space and time may be more resilient to extreme conditions, although further work integrating abundance data is needed. We also identified a small number of species (approximately 10%) that failed to shift at all; these species are likely to be particularly vulnerable to climate change, and should be prioritized for conservation intervention.

Urbanization reduces biodiversity and accelerates biotic homogenization, including among pollinators. However, questions remain concerning urban pollinator ecology and conservation, particularly: to what extent does pollinator alpha and beta diversity decline across urban landscapes, and what drives these patterns? We investigated the impacts of local and landscape characteristics on community diversity in four increasingly urban butterfly metacommunities, collecting data on butterfly diversity, butterfly host plant richness, flowering plant richness, and impervious surface area in the landscape. Suburban and urban metacommunities supported similarly low levels of butterfly diversity compared to a natural peri-urban metacommunity. Host plant richness increased butterfly diversity, but floral richness was correlated with reduced diversity, suggesting that many species-rich gardens are low in diversity of plants that support butterflies. In contrast, dissimilarity was driven by both local and landscape scale factors. Dissimilarities in site area and landscape impervious surface area drove overall dissimilarity, while these factors in addition to host and floral communities drove butterfly turnover (loss with replacement) and nestedness (loss without replacement). Our findings demonstrate that alpha and beta diversity are driven by different factors, and both must be considered to understand urban butterfly ecology and conservation. While butterfly species are filtered out of landscapes with high amounts of impervious surface area, even small sites can support diverse butterfly communities if they contain rich assemblages of butterfly host plants. Our comparative analysis of metacommunities provides a framework for future studies in human-altered environments.

Climate change may introduce conditions beyond species’ tolerances; to survive, species must avoid these extremes. Phenological shifts are one strategy, as species move their activity or life history events in time to avoid extreme conditions. Species may also shift in space, moving their ranges poleward to escape extremes. However, whether species are more likely to exhibit one or both strategies, and whether this can be predicted based on a species’ functional traits, is unknown. Using a powerful macroecological dataset of European and North American odonate observations, we assessed range and phenology shifts between two time periods (1980-2002 and 2008-2018) to measure the strength and direction of the association between responses. Species with the greatest poleward range shifts also showed the largest phenological shifts toward earlier annual activity periods, with half of all species shifting in both space and time. This response was consistent across continents, despite highly divergent land use and biogeographical histories in these regions. Surprisingly, species’ range and phenology shifts were not related to functional traits; rather, southern species shifted their range limits more strongly, while increasing temperature variability hindered range shifts. By reducing risk through phenological shifts, the resulting larger populations may be more likely to disperse and expand species’ ranges. Species shifting in both space and time may be more resilient to extreme conditions, although further work integrating abundance data is needed. We also identified a small number of species (approximately 10%) that failed to shift at all; these species are likely to be particularly vulnerable to climate change, and should be prioritized for conservation intervention.

Canada’s provinces and territories govern species at risk across most of Canada, with the federal Species at Risk Act generally covering only aquatic species, migratory birds, and species living on federal land. More than a decade after a 2012 report by the environmental law charity Ecojustice on species at risk protection in Canada, we use the same criteria to evaluate the current state of provincial and territorial species at risk legislation, and we provide updates on changes in each jurisdiction since 2012. These criteria are as follows: whether at-risk species are being identified, whether these species are being protected, whether their habitat is being protected, and whether species recovery plans are being created and implemented. We find that there is considerable variation across jurisdictions, with shortcomings that result in inadequate protections for at-risk species, as well as strong components that should be adopted by all jurisdictions. We recommend seven key areas for improvement: dedicated and harmonized legislation, limited discretionary power, increased embrace of scientific and Indigenous knowledge, appropriate timelines for actions, reasonable exemptions to protections, habitat protection across land ownership types, and transparency throughout the process. We urge policymakers to address current shortcomings as they work toward meeting Canada’s biodiversity conservation commitments.

Dispersal contributes vitally to metacommunity structure. However, interactions between dispersal and other key processes have rarely been explored, particularly in the context of multitrophic metacommunities. We investigated such a metacommunity in naturally fragmented habitats populated by butterfly species (whose dispersal capacities were previously assessed), flowering plants, and butterfly predators. Using data on butterfly species abundance, floral abundance, and predation (on experimentally placed clay butterfly models), we asked how dispersal ability mediates interactions with predators, mutualists, and the landscape matrix. In contrast to expectations, high densities of strong dispersers were found in more isolated sites and sites with low floral resource density, while intermediate dispersers maintained similar densities across isolation and floral gradients, and higher densities of poor dispersers were found in more connected sites and sites with higher floral density. These findings raise questions about how strong dispersers experience the landscape matrix and the quality of isolated and low‐resource sites. Strong dispersers were able to escape habitat patches with high predation, while intermediate dispersers maintained similar densities along a predation gradient, and poor dispersers occurred at high densities in these patches, exposing them to interactions with predators. This work demonstrates that species that vary in dispersal capacities interact differently with predators and mutualist partners in a landscape context, shaping metacommunity composition.

The impact of multitrophic interactions on metacommunity structure, despite extensive theory and modeling/manipulative studies, has remained largely unexplored within naturally occurring metacommunities. We investigated the impacts of mutualistic partners and predators on a butterfly metacommunity, as well as the impacts that local and landscape characteristics have across three trophic levels: flowering plants, butterflies, and butterfly predators. Using data for butterfly diversity/richness, flowering plant diversity/richness, and butterfly predation (on clay butterfly models) across 15 grassland sites, we posed 3 questions. (1) How do mutualist metacommunity structure, predation pressure, and local and regional habitat characteristics affect butterfly metacommunity structure? (2) How do local and regional habitat characteristics affect flowering plant metacommunity structure? (3) How do local and regional habitat characteristics affect predation pressure? Floral diversity and richness had a positive effect on butterfly diversity and richness (Question 1). Site size positively affected floral diversity and richness (Question 2), and through this relationship site size had an indirect positive effect on butterfly diversity and richness (Question 1). In contrast to previous work, no other variables impacted butterfly diversity/richness. This result was particularly surprising for predation pressure: Our results suggest that within our study system, butterfly community diversity and richness are not strongly impacted by predation. Predator attacks occurred more in larger and more isolated sites (Question 3), suggesting that predators respond more strongly to landscape characteristics than abundance or diversity of butterfly prey species. This decoupling of predation pressure and butterfly communities suggests that conserving and restoring healthy predator populations may not negatively impact butterfly communities. If diverse plant communities are maintained, even small and isolated habitat patches can be valuable for butterfly conservation, which may influence reserve design and habitat restoration strategies.

Premise of the Study: Phenological mismatch has received attention in plant–pollinator interactions, but less so in seed dispersal mutualisms. We investigated whether the seasonal availability of myrmecochorous seeds is well matched to the seasonal activity patterns of seed‐dispersing ants.Methods: We compared seasonal timing of seed removal by a keystone seed‐dispersing ant, Aphaenogaster rudis, and fruit dehiscence of several species of plants whose seeds it disperses in a deciduous forest in southern Ontario, Canada. We examined the timing of elaiosome “robbing” by the nonnative slug Arion subfuscus and tested whether seed removal by ants declines in response to supplementation with additional elaiosome‐bearing seeds (ant “satiation”).Key Results: Seed removal from experimental depots peaked early in the season for all plant species and correlated with temperature. In contrast, elaiosome robbing by slugs increased late in the season and thus may disproportionately affect plants with late‐dehiscing fruits. Ant colonies removed seeds at similar rates regardless of seed supplementation, indicating that satiation likely does not impact seasonal patterns of seed dispersal in this system. Fruits of the five myrmecochorous plant species in our study dehisced at discrete intervals throughout the season, with minimal overlap among species. Peak dehiscence did not overlap with peak seed removal for any plant species.Conclusions: Fruit dehiscence of myrmecochorous plants and peak ant seed dispersal activity occur asynchronously. Whether future climate warming will shift ant and plant phenologies in ways that have consequences for seed dispersal remains an open question.