Influences of extreme weather, climate and pesticide use on invertebrates in cereal fields over 42 years

Abstract

Cereal fields are central to balancing food production and environmental health in the face of climate change. Within them, invertebrates provide key ecosystem services. Using 42 years of monitoring data collected in southern England, we investigated the sensitivity and resilience of invertebrates in cereal fields to extreme weather events and examined the effect of long-term changes in temperature, rainfall and pesticide use on invertebrate abundance. Of the 26 invertebrate groups examined, eleven proved sensitive to extreme weather events. Average abundance increased in hot/dry years and decreased in cold/wet years for Araneae, Cicadellidae, adult Heteroptera, Thysanoptera, Braconidae, Enicmus and Lathridiidae. The average abundance of Delphacidae, Cryptophagidae and Mycetophilidae increased in both hot/dry and cold/wet years relative to other years. The abundance of all 10 groups usually returned to their long-term trend within a year after the extreme event. For five of them, sensitivity to cold/wet events was lowest (translating into higher abundances) at locations with a westerly aspect. Some long-term trends in invertebrate abundance correlated with temperature and rainfall, indicating that climate change may affect them. However, pesticide use was more important in explaining the trends, suggesting that reduced pesticide use would mitigate the effects of climate change.

Critical Decline of Earthworms from Organic Origins under Intensive, Humic SOM-Depleting Agriculture

“…This was corroborated by Ewald et al (2015) [71] who charted only slight decline in abundance in 42 years (1970-2011) in 26 invertebrate groups (including pests, despite pesticide intensification) in agrichemical cereal fields in southern UK suggesting stability, albeit at a new and much lower biodiversity level (β curve as in Figure 5). However, since no uncultivated nor organic controls were compared, biomass was unmeasured, and as they especially omitted earthworms, this latter work is therefore not particularly relevant.…”

Impacts of a millennium drought on butterfly faunal dynamics

“…While many studies of species and ecosystems have looked at climate impacts by using the average change in historical or projected climatic conditions [3,4], we know far less about the ecological impacts of extreme weather events on wild organisms [5][6][7]. In part this is due to the regional geography in which extreme weather events occur, which requires baseline biological data as well as appropriatelyscaled climatological data for a particular region prior to an event [8].…”

Achteruitgang insectenpopulaties in Nederland: trends, oorzaken en kennislacunes

“…• Bij een deel van de insectensoorten is er sprake van sterke aantalsfluctuaties, onder andere onder invloed van weersextremen, fluctuaties in lokale milieucondities en stochastische processen (Mutshinda, O'Hara et al 2009;Paquette, Garant et al 2013;Ewald, Wheatley et al 2015). …”

“…Doordat de meeste insecticiden niet specifiek zijn, kunnen veel niet-doelwitsoorten negatief beïnvloed worden, maar zelfs specifieke middelen hebben vaak negatieve effecten op andere insectensoorten (Moreby, Southway et al 2001). Bij herbiciden en fungiciden zijn de effecten over het algemeen minder sterk en vooral indirect, bijvoorbeeld via een verminderde beschikbaarheid van voedsel (Ewald, Wheatley et al 2016) of via interacties met andere drukfactoren (Ewald, Wheatley et al 2015;Ewald, Wheatley et al 2016;Myers, Antoniou et al 2016;McArt, Urbanowicz et al 2017). De effecten op terrestrische en (deels) aquatische insecten worden hier apart besproken.…”

“…De effecten hiervan zijn nog slecht bekend. Voor negatieve effecten van extreme droogte bestaat groeiende evidentie (Wallis de Vries, Baxter et al 2011;Oliver, Marshall et al 2015;Tack, Mononen et al 2015), maar voor hevige neerslag is deze nog anekdotisch (Ewald, Wheatley et al 2015;Wallis de Vries, 2011).…”