The contrasting response of cavity-nesting bees, wasps and their natural enemies to biodiversity conservation measures

Oct 17, 2026

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Implementation of agri-environmental schemes (AES) is evaluated as a key strategy for sustaining biodiversity and ecosystem services in European agricultural landscapes, emphasizing how different novel biodiversity measures vary in effectiveness. Trap nests were deployed across 3×3 km landscapes in Germany where farmers used distinct measures. Effects were tested for distance, area and quality of the nearest three measures, plus proximity to forest and oilseed rape, and landscape connectivity on insects and natural enemies. Results show quality-driven increases, distance-related declines and contrasting responses between bees and wasps.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages15

Reading Time38 min

AccessFree to download

Abstract

Introduction

Forest promotes cavity-nesting insects

DOI: 10.1111/icad.12638 ORIGINA L ARTICLE The contrasting response of cavity-nesting bees, wasps and their natural enemies to biodiversity conservation measures Nicole Beyer 1 | Josephine Kulow 1,2 | Jens Dauber 1,3 1Thünen Institute of Biodiversity, Braunschweig, Germany 2Functional Agrobiodiversity, Department of Crop Sciences, University of Göttingen, Göttingen, Germany 3Biodiversity of Agricultural Landscapes, Institute of Geoecology, Technische Universität Braunschweig, Braunschweig, Germany Correspondence Nicole Beyer, Thünen Institute of Biodiversity, Bundesallee 65, 38116 Braunschweig, Germany. Email: [nicole.beyer@thuenen.de](nicole.beyer@thuenen.de) Funding information Bundesministerium für Ernährung und Landwirtschaft; Landwirtschaftliche Rentenbank, Grant/Award Number: 817759 Editor: Raphael K. Didham and Associate Editor: Nick Littlewood Abstract 1. The implementation of agri-environmental schemes (AES) is a major tool to sustain biodiversity and ecosystem services in European agricultural landscapes. The benefit of different types and features of novel biodiversity measures needs to be assessed in order to successfully conserve insect communities in agroecosystems. 2. We set up trap nests in 3 􀀁 3 km landscapes in Germany, in which farmers implemented different novel biodiversity measures. We tested the effect of different features of the closest three biodiversity measures (i.e. distance to measures, measures’ area, measures’ quality) and of the proximity to forest and oilseed rape and of landscape connectivity on the abundance and species richness of cavitynesting bees, wasps and their natural enemies. 3. We found total cavity-nesting insect abundances to increase with measures’ quality and to decline with increasing distance to oilseed rape and forest. Parasitism and mortality rates declined with edge density. 4. Cavity-nesting bees were not affected by biodiversity measures. Total wasp and herbivore-predating wasp abundances increased in proximity to biodiversity measures. The abundance and species richness of all wasps, natural enemies and spiderpredating wasps declined with increasing distance to forest. 5. Cavity-nesting wasps benefit from biodiversity measures, while effects on solitary bees might only be detectable after several years after measure establishment. The proximity to forest is a major factor promoting insects as forest edges provide food, nesting sites and shelter. We emphasise the need for long-term insect monitoring and an increasing focus of future AES on the creation of nesting habitats for effective insect conservation. KEYW ORD S conservation measures, flower strips, habitat enhancement, habitat quality, insect decline, landscape structure, parasitoids, pest control, pollination, pollinators INTRODUCTION Insects provide important ecosystem services of high economic value Nicole Beyer and Josephine Kulow contributed equally to this study. (Losey & Vaughan, 2006) and the provisioning of floral resources is a This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2023 The Authors. Insect Conservation and Diversity published by John Wiley & Sons Ltd on behalf of Royal Entomological Society. FOREST PROMOTES CAVITY-NESTING INSECTS 469 key component for successful insect conservation (Potts et al., 2003; Roulston & Goodell, 2011) . Wild bees are essential pollinators for many global food crops (Klein et al., 2007) as they forage on floral nectar and pollen, on which their larvae depend on (Westrich, 2019) . Adult solitary wasps feed on floral nectar, while their larvae are fed with specific arthropod prey (Witt, 2009) . Solitary aculeate wasps thus provide pest control services, regulate arthropod populations and support pollination of flowering plants (Brock et al., 2021) . As insect num

FAQs

What biodiversity conservation approach is analyzed in the study?

The study assesses how agri-environmental schemes (AES) with novel biodiversity measures affect biodiversity and ecosystem services in European agricultural landscapes.

How were the insects and natural enemies measured?

Trap nests were installed across multiple 3×3 km landscapes in Germany where farmers implemented different biodiversity measures.

Do cavity-nesting bees and wasps respond similarly to the measures?

No. Cavity-nesting bees were not affected by the measures, while total wasp and herbivore-predating wasp abundances increased near biodiversity measures; distance to forest also reduced wasp natural enemies and spider-predating wasps.

Oct 17, 2026

Uploaded by Mia