Agri‐environmental schemes affect the trophic niche size and diet of common carabid species in agricultural landscapes

Abstract

1. Carabids are abundant in agroecosystems and provide biocontrol services by feeding on weed seeds and pests. We compare the effects of two fundamentally different agri-environmental schemes (AES) on the numeric and trophic responses of four common carabid species: Anchomenus dorsalis, Poecilus cupreus, Pseudoophonus rufipes and Pterostichus melanarius.2. In six cereal fields under organic farming and six sown flowering fields, 10 290 individuals of the four species were sampled to quantify their numeric response. The activity density of all species was higher in organically managed cereal fields compared to flowering fields.3. We analysed naturally occurring stable isotope ratios of carbon and nitrogen in 138 carabid individuals to quantify isotopic niches and the diet contribution of soilversus plant-based resources. Resources from the soil ('brown') energy channel were more important than resources from the plant ('green') energy channel in the diet of all species, particularly in P. melanarius.4. Isotopic niches were larger for P. rufipes and P. melanarius in flowering fields than in organically managed cereal fields. Moreover, differences between AES types were observed in the diet contribution derived from both energy channels: A. dorsalis and P. cupreus incorporated higher proportions of plant-based resources in organically managed cereal fields compared to flowering fields. 5. Similar numeric, but different trophic responses suggest that AES type may alter arthropod food webs beyond simple changes in carabid densities. Such 'hidden' modifications in the resource utilisation of generalist predators deserve more attention to adequately evaluate the ecological consequences of AES.

Landscape and agri-environmental scheme effects on ant communities in cereal croplands of central Spain

“…All ants are eusocial insects that depend on stable, usually large and long-lived, permanent nests (Höldobler and Wilson, 2009). Hence, its sensitivity to management in periodically disturbed systems such as croplands would be stronger than sensitivity of the short-lived or solitary arthropod groups best studied to date, bees, butterflies or carabids, mainly (Albrecht et al, 2020;Batáry et al, 2011;Mader et al, 2018Mader et al, , 2017Martin et al, 2019;Scheper et al, 2013), which could be more sensitive to year-to-year weather fluctuations (Pollard, 1991;Roy et al, 2001) and less indicative of background trends.…”

The Estimation of the Initial Stage of Succession of Green-pine Trees Windfall in the Eastern Moscow Suburbs

“…Ground beetles are the few families of Coleoptera widespread in biotopes, which experience various types of anthropogenic influence [11][12][13][14][15][16][17][18][19]. This paper presents the analysis of the species composition and ecological structure of ground beetle complexes in windfalls and in the areas not affected by this type of impact.…”

Effect of global climate change on the distribution of Anchomenus dorsalis (Coleoptera, Carabidae) in Europe

“…As for diet contribution, beetles A. dorsalis were observed incorporating more plant-based resources in organically managed cereal fields than in the flowering fields (Mader et al 2018). The study (Pajač Živković et al 2018) showed the positive effect of exclusion nets on A. dorsalis in an apple orchard of Croatia, thus confirming their value in assessing the introduction of new agricultural measures into practice.…”