Multiscale drivers of carabid beetle (Coleoptera: Carabidae) assemblages in small European woodlands

Abstract

Aim The spatio‐temporal connectivity of forest patches in lowland agricultural landscapes and their age matter to explain current biodiversity patterns across regional as well as biogeographical extents, to the point that their effect exceeds the one of macroclimate for plant diversity in the understorey of temperate forests. Whether this remains true for other taxonomic groups is still largely unknown. Yet, this relative influence has important consequences for ecosystem functioning and the delivery of ecosystem services. Focusing on carabid beetle assemblages, we assessed the relative importance of macroclimatic, landscape and patch attributes in driving local species richness (α‐diversity) and species dissimilarity between patches (β‐diversity). Location Deciduous forest patches in seven regions along a 2,100‐km‐long latitudinal gradient across the European temperate forest biome, from southern France to central Sweden. Methods We sampled 221 forest patches in two 5‐km × 5‐km landscape windows with contrasting management intensities. Carabid beetles were classified into four habitat‐preference guilds: forest‐specialist, forest‐generalist, eurytopic and open‐habitat species. We quantified the multi‐level environmental influence using mixed‐effects models and variation partitioning analysis. Results We found that both α‐ and β‐diversity were primarily determined by macroclimate, acting as a large‐scale ecological filter on carabid assemblages among regions. Forest‐patch conditions, including biotic and abiotic heterogeneity as well as patch age (but not patch size), increased α‐diversity of forest species. Landscape management intensity weakly influenced α‐diversity of forest species, but increased the number of non‐forest species in forest patches. Beta diversity of non‐forest species increased with patch heterogeneity and decreased with landscape management intensity. Main conclusions Our results highlight the leading role of broad macroclimatic gradients over local and landscape factors in determining the composition of local carabid communities, thereby shedding light on macroecological patterns of arthropod assemblages. This study emphasizes the urgent need for preserving ancient forest patches embedded in agricultural landscapes, even the small and weakly connected ones.

Effects of varying retention tree patterns on ground beetle (Coleoptera: Carabidae) taxonomic and functional diversity

“…In addition to retention pattern, other processes likely affect levels of carabid community dissimilarity between retention patches and clear-cuts. Factors such as landscape composition (Barbaro et al 2007), land use history (Neumann et al 2017), and climate (Marrec 2021) influence forest carabid beetle communities and likely contribute to the large within treatment variability we observed in this study. We sampled a wide range of environmental conditions present on managed forests in the PNW and landscape composition, climate, and topography strongly varied across blocks and stands.…”

What shapes ground beetle assemblages in a tree species-rich subtropical forest?

“…For example, studies using the same sampling approach in Central European forests have reported 60 times more ground beetle specimens and 90 times more ground beetle biomass ( Homburg et al 2019 ; Hülsmann et al 2019 ). Similarly, the number of species from temperate forests is higher ( Nolte et al 2017 ; Marrec et al 2021 ). Further south, towards the European subtropical zone, Brandmayr et al (1983) found similar low catches of both individuals and species, but in a less plant diverse forest (Mediterranean forest dominated by Quercus ilex (Linnaeus, 1753)).…”

“…During plot establishment, a comprehensive set of environmental variables of biotic and abiotic habitat characteristics was collected (Bruelheide et al 2011). We asked if seven variables, known to influence ground beetles assemblages (e.g., Assmann 1999;Antvogel and Bonn 2001;Marrec et al 2021) could predict the abundance, species richness and biomass of ground beetles. The age of the forest included in each plot was estimated using stem core measurements of the tree with the fifth largest diameter at breast height within each plot.…”

“…A substantial part of this biodiversity consists of arthropods, which are involved in many ecosystem processes ( Basset et al 2012 ; Schuldt et al 2015b ; Stork 2018 ). Numerous biotic and abiotic variables can influence their diversity, but also the abundance and biomass of these arthropods ( Rainio and Niemela 2003 ; Mottl et al 2020 ; Marrec et al 2021 ). Trees structure forest ecosystems and, as they are the most important primary producers of biomass, they provide the basis for much of the food web consisting of decomposers, herbivores, and predators.…”

“…Moreover, ground beetles in temperate and boreal regions are known to be sensitive to numerous edaphic variables (e.g., pH-value: Paje and Mossakowski 1984 ; moisture: Antvogel and Bonn 2001 ). Even effects of land-use legacy, tree age, vegetation structure and succession are known ( Terrell-Nield 1990 ; Assmann 1999 ; Jelaska et al 2011 ; Marrec et al 2021 ). In general, ground beetles are considered as a well-known taxon for bio-indication since numerous species react sensitively to small changes in environmental variables ( Koivula 2011 ).…”