Among the many concerns for biodiversity in the
Anthropocene, recent reports of flying insect loss are particularly
alarming, given their importance as pollinators, pest control agents,
and as a food source. Few insect monitoring programmes cover the large
spatial scales required to provide more generalizable estimates of
insect responses to global change drivers.
We ask how climate and surrounding habitat affect
flying insect biomass using data from the first year of a new monitoring
network at 84 locations across Germany comprising a spatial gradient of
land cover types from protected to urban and crop areas.
Flying insect biomass increased linearly with
temperature across Germany. However, the effect of temperature on flying
insect biomass flipped to negative in the hot months of June and July
when local temperatures most exceeded long-term averages.
Land cover explained little variation in insect
biomass, but biomass was lowest in forests. Grasslands, pastures, and
orchards harboured the highest insect biomass. The date of peak biomass
was primarily driven by surrounding land cover, with grasslands
especially having earlier insect biomass phenologies.
Standardised, large-scale monitoring provides key
insights into the underlying processes of insect decline and is pivotal
for the development of climate-adapted strategies to promote insect
diversity. In a temperate climate region, we find that the positive
effects of temperature on flying insect biomass diminish in a German
summer at locations where temperatures most exceeded long-term averages.
Our results highlight the importance of local adaptation in climate
change-driven impacts on insect communities.