Ground Beetle (Coleoptera: Carabidae) Assemblages and Slug Abundance in Agricultural Fields Under Organic and Low-Input Conventional Management Within a Long-Term Agronomic Trial in Central Italy

Abstract

Inside a long-term agronomic trial aimed at evaluating the effects of organic and low-input conventional management systems on soil fertility and arable crop production, we selected six fields bordered by hedgerows, three under each management system. Here, we analyzed the carabid assemblages and the slug abundance. Samplings took place in five different periods, across 1 yr of observations. The carabid abundances were similar in organic and conventional fields. The Shannon–Wiener diversity index (H’) showed a higher value in the conventional fields, although in the organic fields, a higher number of species were observed. The multivariate analysis described similar carabid communities, but excluding the period factor, it showed a significant influence of the management system. There was no difference between the captures of traps placed along the hedgerow and in the middle, whereas in the conventional fields, the hedgerow traps captured a higher number of specimens, showing a role of the hedgerow as carabid reservoir. The slugs were present mainly while green manure was grown on the organic fields where also Poecilus cupreus Linné, 1758 (Coleoptera: Carabidae) was captured abundantly.

Impact of arable farming management on the biodiversity of Carabidae (Coleoptera)

“…Harpalus rufipes and Poecilus cupreus were the most captured species. These results coincide with the data collected across Europe by other authors ( Rossi et al, 2019 ).…”

“…Carabids are efficient bioindicators in terrestrial ecosystems because of their adaptability and ability to colonize almost all terrestrial habitats and geographical locations, their quick response to environmental changes, the ease in collecting them, and their relatively stable taxonomy. They are also useful organisms in agroecosystems due to their role as predators of crop insect pests and slugs, thus reducing their populations ( Rossi et al, 2019 ). Preserving high biodiversity in agroecosystems makes agricultural production more sustainable and economically viable.…”

“…Much evidence shows how agroecological practices can mean that ecological systems have less of an impact on carabid habitats than integrated ones. Some soil management practices such as reduced tillage or cover cropping can considerably influence the effects of organic management on carabid biodiversity ( Rossi et al, 2019 , Legrand et al, 2011 ). The Shannon-Weaver index, which we consider sufficient, was used to evaluate species diversity.…”

Slug Monitoring and Impacts on the Ground Beetle Community in the Frame of Sustainable Pest Control in Conventional and Conservation Agroecosystems

“…Although P. cupreus seems to be less efficient in slug control than Pterostichus spp. [48,49], it is a polyphagous species able to reduce insect pest populations [51] and associated with slugs in organic farms with green manure [83]. Other Carabidae, both generalist feeders and granivorous (Bembidion, Brachinus, and Harpalus), were more common in conservation plots with vetch as cover crop and, to a lesser extent, with the mixture cover, than in conventionally managed plots.…”

Revisiting the study of the life cycles of predatory ground beetles (Coleoptera, Carabidae) in the agrolandscape of the foothill zone of Krasnodar Krai

“…Despite the significant success achieved in recent years in studying the life cycles of ground beetles in Russia, it should be noted that the latter were reconstructed mainly in natural biocenoses, the life cycles of ground beetles in agrocenoses, including Krasnodar Krai, are still very poorly studied [1 , 2, 3, 4]. At the same time, with the growing pace of organic farming development in general and in this region in particular [5,6], the search for ways to activate effective non-specific local entomophages is of great importance [7, etc.]. Knowledge of life cycles makes it possible to understand when the maximum activity of ground beetles should be expected, and whether such peaks will be synchronized with the appearance and periods of harmfulness of specific phytophages.…”