Improving insect conservation management through insect monitoring and stakeholder involvement

Abstract

In recent years, the decline of insect biodiversity and the imminent loss of provided ecosystem functions and services has received public attention and raised the demand for political action. The complex, multi-causal contributors to insect decline require a broad interdisciplinary and cross-sectoral approach that addresses ecological and social aspects to find sustainable solutions. The project Diversity of Insects in Nature protected Areas (DINA) assesses insect communities in 21 nature reserves in Germany, and considers interactions with plant diversity, pesticide exposure, spatial and climatic factors. The nature reserves border on agricultural land, to investigate impacts on insect diversity. Part of the project is to obtain scientific data from Malaise traps and their surroundings, while another part involves relevant stakeholders to identify opportunities and obstacles to insect diversity conservation. Our results indicate a positive association between insect richness and biomass. Insect richness was negatively related to the number of stationary pesticides (soil and vegetation), pesticides measured in ethanol, the amount of area in agricultural production, and precipitation. Our qualitative survey along with stakeholder interviews show that there is general support for insect conservation, while at the same time the stakeholders expressed the need for more information and data on insect biodiversity, as well as flexible policy options. We conclude that conservation management for insects in protected areas should consider a wider landscape. Local targets of conservation management will have to integrate different stakeholder perspectives. Scientifically informed stakeholder dialogues can mediate conflicts of interests, knowledge, and values to develop mutual conservation scenarios.

Insect biomass of protected habitats under the impact of arable farming in Germany

“…On average, we observed an increase in maximum insect biomass per day along the transect from the edge towards the centre of the nature protected area in 2020 and from MT3 to MT4 in 2021. These findings emphasise our previous results on spillover effects into the NPA (Köthe et al, 2023b), which documented strong chemical edge effects and negative impacts from adjacent arable land on plant communities in nature protected areas. In addition, the number of endangered plant species rose with increasing proximity to the edge of the field.…”

“…Therefore, the bias due to the relocation of the trap from the arable land in the second year seems to be small. Overall, the insect biomass was higher only on arable land at a site with environmentally friendly farming and a species rich vegetation including many endangered plants (Köthe et al, 2023b; Table 1: Oderhänge Mallnow). In two cases (Riedensee, Insel Koos), the highest mean biomass was found in the second year 2021 on previous arable land, and not anymore in the NPA, which can be attributed to a shift from arable land to newly established wildflower strips.…”

“…Few sampling sites had the maximum insect biomass on arable land. At the Oderhänge Mallnow site, the environmentally friendly farming practises over years led to a high diversity of plants including endangered species typical for arable land (Köthe et al, 2023b).…”

“…Moreover, due to the comparability in methodology, the data can be collated with those of Hallmann et al (2017). In addition to insect data, landscape elements and their spatial distribution pattern (Eichler et al, 2022), vegetation (Köthe et al, 2023b; Swenson et al, 2022), and pesticide residues were measured (Brühl et al, 2021) accompanied by exchange with local stakeholders for developing solutions for improved insect protection (Fickel et al, 2020; Köthe et al, 2023a; Lehmann et al, 2021).…”

No recovery in the biomass of flying insects over the last decade in German nature protected areas

“…Since then, several studies provided evidence that insect biomass decline involves a loss in diversity (Hallmann, Ssymank, Sorg, de Kroon, & Jongejans, 2021 ; Hallmann, Ssymank, Sorg, Kroon, & Jongejans, 2021 ; Hausmann et al., 2022 ). In addition, habitat fragmentation is a major driver of insect decline and its negative impact on insect populations is a major problem in many regions (Köthe, Bakanov, Brühl, Eichler, et al., 2023 ; Köthe, Bakanov, Brühl, Gemeinholzer, et al., 2023 ; Köthe, Schneider, Bakanov, Brühl, et al., 2023 ; Tscharntke et al., 2002 ; Tscharntke & Brandl, 2004 ). Due to their species richness, their biomass and their diverse specialisations, insects play a key role in almost all ecosystems.…”