Jeremy T. Kerr

As biodiversity protection and restoration goals grow, so must impact assessments that can guide conservation efforts on the ground. This is especially true in agricultural areas, where competing pressures on use of the land leave little room for manoeuvre for conservation actions. As much as they are needed, biodiversity impact assessments are limited by the difficulty of tracking wildlife and associated ecosystem services at scale. This special collection features a series of original articles that contribute broadly to the topic of monitoring biodiversity dynamics in agroecosystems. They are rooted in Southern Ontario, a densely populated and intensively farmed region with a rich ecological history, and programs like the Alternative Land Use Services, which support on-farm conservation practices, including habitat restoration on agriculturally marginal field areas. Contributions fall under two broad themes: (1) impact of habitat management and agricultural practices on biodiversity, with a particular focus on regionally important taxa and ecosystems (arthropods in grasslands, aquatic food webs in riparian ecosystems); and (2) challenges and opportunities for monitoring arthropods across agricultural landscapes. The collection illustrates the value of partnerships between regional organizations and researchers for producing locally applicable insights with relevance to the broader literature.

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 contributes to widespread shifts in body size across taxa which can impact population and community dynamics. However, the reasons for variability in the direction and intensity of responses remain uncertain. Smaller body size improves thermoregulatory efficiency but can increase dehydration risk. Changes in species' body size is likely to balance the tradeoffs of thermoregulation and osmotic balance when responding to shifts in thermal and aridity regimes associated with climate change. Using 119,183 bird and 183,087 mammal body mass, and 15,562 bird and 239,600 mammal body length records, along with species' thermal and aridity limits based on their range geographies, we tested for associations between body size and climatic conditions. We also assessed the impacts of human land use extent and interactions with species thermal environments. We found that smaller body mass measurements across taxa are associated with conditions closer to species' upper thermal (hot) and lower aridity (dry) tolerance limits. Agricultural land use extent was found to be positively associated with body mass measurements for both bird and mammal species. Shorter body lengths were observed for both birds and mammals the closer species were to their upper thermal limits. Further we found that thermal and aridity conditions interacted resulting in stronger negative associations between body mass and hotter temperatures the closer species were to their dry tolerance limits. Our results are consistent with predictions that differences in body size within bird and mammal species are driven by thermoregulatory pressures associated with thermal and aridity regimes. While species' range geographies and phenology are widely known to respond to anthropogenic climate change, the shifts in species' body sizes detected here are a third biotic response that exerts similarly profound ecological, evolutionary, and conservation effects.

Climate changes pose risks for bumblebee populations, which have declined relative to the growing frequency and severity of warmer temperature extremes. Bumblebees might mitigate the effects of such extreme weather through colonial behaviours. In particular, fanning behaviour to dissipate heat is an important mechanism that could reduce exposure of thermally sensitive offspring to detrimental nest temperatures (T_n). The allocation of workers towards fanning over prolonged periods could impact foraging activity that is essential for colony-sustaining resource gathering. Colony maintenance and growth could suffer as a result of nutritional and high ambient temperature (T_a) thermal stress. It remains uncertain whether a compromise occurs between thermoregulation and foraging under chronic, sublethal heat events and how colony success is impacted as a result. This study held colonies of Bombus impatiens at constant high T_a (25°C, 30°C or 35°C) for 2 weeks while quantifying the percentage of foragers, fanning incidence, nest temperature (T_n) and other metrics of colony success such as the percentage of adult emergence and offspring production. We found that foraging and adult emergence were not significantly affected by T_a, but that thermoregulation was unsuccessful at maintaining T_n despite increased fanning at 35°C. Furthermore, 35°C resulted in workers abandoning the colony and fewer offspring being produced. Our findings imply that heatwave events that exceed 30°C can negatively impact colony success through failed thermoregulation and reduced workforce production.

Background: Starting in the early 20th century, ticks and their pathogens have been detected during surveillance efforts in Canada. Since then, the geographic spread of tick vectors and tick‐borne pathogens has steadily increased in Canada with the establishment of tick and host populations. Sentinel surveillance in Canada primarily focuses on Ixodes scapularis, which is the main vector of Borrelia burgdorferi, the bacterium causing Lyme disease. Other tick‐borne pathogens, such as Anaplasma, Babesia, and Rickettsia species, have lower prevalence in Canada, but they are emerging or re‐emerging in tick and host populations.Aims/Materials & Methods: Here, we assessed the historical associations between tick vectors, hosts and pathogens and identified spatiotemporal clusters of pathogen presence in ticks in Canada using data extracted from the literature.Results: Approximately one‐third of ticks were infected with a pathogen, and these ticks were feeding primarily on bird and mammal hosts. B. burgdorferi was the most detected pathogen and I. scapularis harboured the greatest number of pathogens. We identified several spatial outliers of high pathogen presence in ticks in addition to five spatiotemporal clusters in southern Canada, all of which have long‐established tick populations. Six spatiotemporal clusters of high pathogen presence in ticks were also identified based on surveillance method, with four clusters associated with passive surveillance and two clusters associated with active surveillance.Discussion: Our review represents the first systematic assessment of the literature that identifies historical associations and spatiotemporal changes in tick‐host‐pathogen disease systems in Canada over broad spatial and temporal scales.Conclusion: As distinct spatiotemporal clusters were identified based on surveillance method, it is imperative that surveillance efforts employ standardized methods and data reporting to comprehensively assess the presence, spread and risk of tick‐borne pathogens in tick and host populations.

Insect biodiversity is changing rapidly, driven by a complex suite of pressures, foremost among which are human land use, land-use intensification, and increasingly climate change. Bumblebees deliver important pollination services to wild plants and human crops, but we lack large-scale empirical evidence on how land use and climate change interact to drive bumblebee biodiversity changes. We assess bumblebee occupancy responses to interactive effects of land use and climate pressures across North America and Western Europe. Occupancy increases with landscape natural habitat and decreases with the duration of human use of landscapes. Responses to historical climate warming are negative in natural habitats but positive in human land uses, while human land use reduces occupancy most in the centre of species’ temperature niches. We estimate that the combined pressures have reduced bumblebee occupancy by 61% across sampled natural habitats, and 65% across human land uses, suggesting that treating present-day natural habitats as an undisturbed reference is misleading. Our results can inform efforts to conserve bumblebee biodiversity in the face of ongoing land-use changes and accelerating climatic changes. One-sentence summary: Land use and climate change interact to drive large declines in bumblebee occupancy in both natural and human-modified habitats

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.

The rate of human‐induced environmental change continues to accelerate, stimulating the need for rapid and science‐based decision making. The recent availability of cyberinfrastructure, open‐source data and novel techniques has increased opportunities to use ecological forecasts to predict environmental change. But to effectively inform environmental decision making, forecasts should not only be reliable, but should also be designed to address the needs of decision makers with their assumptions, uncertainties, and results clearly communicated. To help researchers better integrate forecasting into decision making, we outline ten practical guidelines to help navigate the interdisciplinary and collaborative nature of forecasting in social–ecological systems. Some guidelines focus on improving forecasting skills, including how to build better models, account for uncertainties and use technologies to improve their utility, while others are developed to facilitate the integration of forecasts with decision making, including how to form effective partnerships and how to design forecasts relevant to the specific decision being addressed. We hope these guidelines help researchers make forecasts more accurate, precise, transparent, and most pressingly, useful for informing environmental decisions.