Distribution of flying insects across landscapes with intensive agriculture in temperate areas

C.J.M Musters,Tracy R Evans,J.M.R Wiggers,Maarten Van 'T-Zelfde,Geert R De Snoo

doi:10.1016/j.ecolind.2021.107889

Abstract

The abundance of insects has been strongly decreasing over the last decades, at least in the temperate zones of North America and Europe. This decrease has generally been attributed to increased human activity, especially increased agricultural production. Therefore, one would expect that insect abundance is spatially distributed according to human land use, more specifically that the abundance of insects in agricultural fields should be affected by the distance to (semi)natural areas. We tested this expectation on an extensive dataset of flying insects from Illinois, USA, and the Netherlands, Europe. Flying insects were collected with yellow sticky boards in agricultural fields at distances up to 566 m from (semi)natural areas. We did not find any effect of distance to (semi)natural area on the abundance of flying insects, after correcting for the confounding variables ‘landscape complexity’, ‘vegetation height’ and ‘plot locations’ (interior vs edge of the field). One might prematurely infer from this that (semi)natural areas do not affect flying insect abundance. We argue that knowing that flying insects are highly mobile, both active and passive, although sticky boards sample local insect abundance, abundance may be homogenized over a relatively large area in open landscapes. Therefore, the study of the effect of nature conservation management on flying insects should be done on spatially large scales, e.g., the landscape level.

Highlights

Based on a recent meta-analysis, Van Klink et al (2020a); (2020b;) have shown a temporal decline of terrestrial insect abundance by about 10.6% per decade and an increase of freshwater insect abundance by about 12.2% per decade at the landscape level
The hypothesis of Hallmann et al about the impact of the surroundings on local obser vations together with the findings of Van Klink et al suggest that the abundance distribution of flying insects over space may differ between nature conservation acreage and agricultural fields
Our results could not show that in temperate agricultural areas of the USA and Europe, the abundance of flying insects is affected by the dis tance tonatural areas up to at least 500 m

Summary

Introduction

Based on a recent meta-analysis, Van Klink et al (2020a); (2020b;) have shown a temporal decline of terrestrial insect abundance by about 10.6% per decade and an increase of freshwater insect abundance by about 12.2% per decade at the landscape level. Both patterns were largely driven by trends in the temperate zones of North America and Europe, from which most observations came. The hypothesis of Hallmann et al about the impact of the surroundings on local obser vations together with the findings of Van Klink et al suggest that the abundance distribution of flying insects over space may differ between nature conservation acreage and agricultural fields. This again could show us the level of spatial scale we should take into consideration when interpreting results like those of Hallmann et al, as well as the size of sampling plot we best would choose in future research

Methods

Results

Conclusion