Insect responses to global change offer signposts for biodiversity and conservation

Abstract

1. Insects have emerged as causes célèbres for widespread concern about human effects on global biodiversity. Here, we consider how insects provide opportunities both to understand the ecological effects of global change and to enhance environmental conservation.2. Despite a limited time frame and geographic extent of quantitative evidence, recent studies of changes to the abundance, distribution, and diversity of insects indicate temporally heterogeneous trends which vary among taxa, regions, and biotopes. These results suggest a) that insect numbers are responding to multiple stressors in the wider context of the changes to fitness, abundance, distributions, and biotic interactions that result from habitat and climate change; and b) that habitat specialists with narrow geographic ranges may be particularly at risk.3. Predictions of the effects of global change on insects based on macroecology and ecophysiology can be tested by combining approaches, including experiments and observations over gradients of latitude, elevation, and urbanization; as well as innovative quantitative analyses of data from standardised monitoring schemes and opportunistic data from historical collections and citizen science. Linking these complementary approaches helps to detect the mechanisms influencing insect responses to the interacting drivers of global change and to inform conservation.4. The impetus and debate provoked by recent high profile reports of insect declines provide opportunities to promote insect conservation, but also to obtain comprehensive evidence for the effects of global change on biodiversity and thus develop and communicate measures to mitigate the threats to ecosystems from global change.

Species traits affect phenological responses to climate change in a butterfly community

“…Finally, butterflies may face divergent pressures while responding both to altered abiotic conditions and host plants that separately shift phenology with climate change 37 . Such separate pressures could trigger trophic mismatches in phenology 1 , 16 , which could reduce survival 38 most acutely among specialized butterflies. Similarly, limitations on individual longevity, increased mortality, or an inability to add additional generations in a season could constrain univoltine species’ response to longer growing seasons.…”

Friend and foe? The effects of grassland management on global patterns of spider diversity

“…The effects of livestock on grasslands have been studied since the beginning of the 20th century (Middleton, 1905) and authors generally agree that moderate removal of above-ground biomass may positively contribute to plant and animal diversity in grasslands (Tälle et al, 2016;Fedrigo et al, 2018;Valliere et al, 2019). However, under high intensities, such management technique may degrade ecosystems through changes in soil chemistry, soil compaction, and habitat homogenization, leading to loss of biodiversity (Oñatibia et al, 2018;He et al, 2019;Torma et al, 2019;Kehoe et al, 2020;Wilson & Fox, 2020).…”

Temperature drives variation in flying insect biomass across a German malaise trap network

“…Climate change is geographically pervasive (Wilson & Fox, 2020) and may explain insect decline in natural areas (e.g. Janzen & Hallwachs, 2019;Welti, Roeder, et al, 2020).…”

“…The effects of climate change are geographically pervasive (Wilson & Fox, 2020) and may explain recent reports of insect decline in natural areas (Janzen & Hallwachs, 2019;Rada et al, 2019;Baranov et al, 2020;Welti et al, 2020b). Some insect taxa are currently benefiting from rising temperatures, which can increase local populations (Kaspari et al, 2019;Baker et al, 2021), diversity (Hofmann et al, 2018), and species' range sizes (Termaat et al, 2019).…”