Abstract
Declines in pollinating insects and wildflowers have been well documented in recent years. Climate change is an emerging threat to insect pollinators and their food plants, but little is known about how whole communities of interacting species will be affected or what impacts there may be on ecosystem services such as pollination. Using a novel open-air field experiment, we simulated an increase in temperature of 1.5°C and rainwater of 40% for two growing seasons to investigate how climate change may impact several within-field features of temperate arable agro-ecosystems: (1) wildflower floral resources; (2) insect visitation; (3) flower-visitor network structure; and (4) wildflower seed set. Experimental warming reduced total floral abundance by nearly 40%, and nectar volumes by over 60% for two species. The species richness of the visiting insects and flowering plants (dominated by annuals) were unaffected by warming, and while a negative impact on visitor abundance was observed, this effect appears to have been mediated by different community compositions between years. Warming increased the frequency of visits to flowers and the complexity of the flower-visitor interaction networks. Wildflower seed set was reduced in terms of seed number and/or weight in four of the five species examined. Increased rainwater did not ameliorate any of these effects. These findings demonstrate the adverse impacts that climate warming might have on annual wildflowers in arable systems and the pollinating insects that feed on them, highlighting several mechanisms that could drive changes in community composition over time. The results also reveal how cascading impacts within communities can accumulate to affect ecosystem functioning.
Highlights
Recent declines in pollinator species diversity and abundance are a major global concern given their importance to human nutrition, economics, ecosystems, and agriculture (IPBES, 2016)
Research employing a latitudinal climate-gradient found that temperature and precipitation were important drivers of structural network properties that are shaped by species richness and phenology (Petanidou et al, 2018)
The network, floral abundance, flowering-plant richness, and all of the flower-visiting insect datasets were collected at the plot level (1 value per plot, per year). These datasets were analysed with generalised linear models (GLMs) including “treatment:year” interaction terms, where “treatment” was a factor with four levels (Control, Water, Heat, Heat + Water) and “year” a factor with two levels (2014 and 2015)
Summary
Recent declines in pollinator species diversity and abundance are a major global concern given their importance to human nutrition, economics, ecosystems, and agriculture (IPBES, 2016). These declines have been attributed to a number of factors such as agricultural intensification, land use change, and disease (Settele et al, 2016; Dicks et al, 2021). Experimental Warming Affects Plant-Pollinator Interactions (IPCC, 2021), climate-warming is expected to compound these pollinator declines by causing range shifts and phenological changes, with some recent evidence for bumblebee convergence across continents (Kerr et al, 2015). The approaches used in these studies have yielded valuable insights into how climatic changes may affect plant-pollinator networks, but so far there have been no experiments, to our knowledge, simulating climate-warming in natural field conditions to investigate this topic
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
