Non‐cropped fragments as important spider reservoirs in a Pampean agro‐ecosystem

Abstract

Agricultural landscapes include patches of cropped and non‐cropped habitats. Non‐cropped fragments are often source habitats for natural pest predators which colonise less suitable agricultural fields. The goals of the present study were: (a) to evaluate the contribution of non‐cropped fragments to agro‐ecosystems as biodiversity reservoirs and ecosystem service providers, by assessing the abundance of spider species and their diversity and (b) to quantify the spatial variation in spider communities across different non‐cropped fragments and crops. We hypothesised that non‐cropped fragments function as spider diversity reservoirs with better conditions for reproduction than crops. We collected spiders from 10 restored fragments having had no disturbance for 20 years and four field edges, along a gradient inside the crop adjacent to each fragment. Overall, we collected 3,591 spiders belonging to 49 species/morphospecies in 14 families. Non‐cropped fragments had a central role in the spider community, as estimated through species–habitat networks. We found differences in the diversity and abundance of spiders between non‐cropped and cropped fragments. However, these differences were only for immature spiders, whose abundance decreased from non‐cropped fragments towards the inside of crops. Our results highlight the importance of non‐cropped fragments in agro‐ecosystems as important source habitat patches, reservoirs of biodiversity and sites where spider reproductive success is possibly higher.

Crop diversity benefits carabid and pollinator communities in landscapes with semi‐natural habitats

“…We found spider abundances not to be affected by the proportion of semi-natural habitats and we detected a non-significant positive trend with increasing crop diversity. Such effects contradict some recent results (Garratt et al, 2017;Opatovsky et al, 2017;Pompozzi et al, 2019), but these seem to indicate that the abundances of ground-dwelling spiders are affected not only by the noncrop habitats in the landscape (Muneret et al, 2019).…”

“…The diversity of carabids from landscapes with high proportions of semi‐natural habitats and high crop diversity being consistent with previous findings (Sirami et al., 2019). Spiders can benefit from non‐crop habitat in the landscape (Garratt, Senapathi, Coston, Mortimer, & Potts, 2017; Opatovsky, Weintraub, Musli, & Lubin, 2017; Pompozzi, Marrero, Haedo, Fritz, & Torretta, 2019) and even more than carabids in some cases (Li, Liu, Duan, Yu, & Axmacher, 2018). However, our data do not show any trend that would indicate an effect of crop diversity or semi‐natural habitats on spider diversity.…”

Peer Review #1 of "Improving insect conservation across heterogeneous landscapes using species–habitat networks (v0.1)"

“…Managing multiple habitats for the conservation of multiple species can be challenging. Recently, it has been proposed to adapt network tools to describe such complex spatial interactions (Hackett et al, 2019;Marini et al, 2019) and to use the resulting species-habitat networks and their metrics to improve conservation of species at the landscape scale (Nardi et al, 2019;Pompozzi et al, 2019;Saunders & Rader, 2019;Lami et al, 2020). First, topology metrics can inform on the architecture and the emerging properties of the whole species-habitat network.…”

Agro‐ecology and biodiversity in the Annals of Applied Biology

“…Two recent papers have considered agro‐ecology and predators in the context of pest control. Pompozzi, Marrero, Haedo, Fritz, and Torretta (2019) assessed the contribution of non‐cropped habitats for supporting spider populations in Argentina. Non‐cropped habitats were found to play an important role in increasing the diversity and abundance of juvenile spiders, and may therefore act as reservoirs of predator populations.…”