Plant species composition and local habitat conditions as primary determinants of terrestrial arthropod assemblages

Abstract

Arthropods respond to vegetation in multiple ways since plants provide habitat and food resources and indicate local abiotic conditions. However, the relative importance of these factors for arthropod assemblages is less well understood. We aimed to disentangle the effects of plant species composition and environmental drivers on arthropod taxonomic composition and to assess which aspects of vegetation contribute to the relationships between plant and arthropod assemblages. In a multi-scale field study in Southern Germany, we sampled vascular plants and terrestrial arthropods in typical habitats of temperate landscapes. We compared independent and shared effects of vegetation and abiotic predictors on arthropod composition distinguishing between four large orders (Lepidoptera, Coleoptera, Hymenoptera, Diptera), and five functional groups (herbivores, pollinators, predators, parasitoids, detritivores). Across all investigated groups, plant species composition explained the major fraction of variation in arthropod composition, while land-cover composition was another important predictor. Moreover, the local habitat conditions depicted by the indicator values of the plant communities were more important for arthropod composition than trophic relationships between certain plant and arthropod species. Among trophic groups, predators showed the strongest response to plant species composition, while responses of herbivores and pollinators were stronger than those of parasitoids and detritivores. Our results highlight the relevance of plant community composition for terrestrial arthropod assemblages across multiple taxa and trophic levels and emphasize the value of plants as a proxy for characterizing habitat conditions that are hardly accessible to direct environmental measurements.

Soundscapes and deep learning enable tracking biodiversity recovery in tropical forests

“…Hence, the combination of innovative methods may allow encompassing biodiversity assessments across multiple sites, leveraging community, functional, and phylogenetic diversity measures. As community composition has been shown to predict environmental gradients 43 , 44 , we hypothesize that community composition derived from CNN models will be correlated with recovery gradients in tropical forests.…”

Micro‐ and macroclimate interactively shape diversity, niches and traits of Orthoptera communities along elevational gradients

“…Within‐site microclimatic variation at even smaller scales than measured in our study (0.01–1 m) could also be crucial for the persistence of certain species, as shown for plants in alpine habitats (Ohler et al., 2020; Scherrer et al., 2011), possibly dampening the microclimate response we measured with this study. Likewise, species responses derived may be interfered by factors interacting with climate, such as moisture (Dvořák et al., 2022; Powell et al., 2007), management (Humbert et al., 2021; Marini et al., 2009), vegetation structure (Gardiner, 2022; Löffler & Fartmann, 2017; Schirmel et al., 2019), composition (Tobisch et al., 2023) and diversity (Fournier et al., 2017; Ramos et al., 2021).…”

Earlier and more uniform spring green-up linked to lower insect richness and biomass in temperate forests

“…We assumed plant species richness to correlate with spatial variability in SOS, and therefore we wanted to distinguish the species richness effect from the spring green-up effect per se in our models. To do so, we made use of the vascular plant species richness dataset 65 from Tobisch et al 66 , which was obtained by vegetation surveys in a 200-m radius around the Malaise trap plots. Between mid-May and the end of July 2019, vegetation was sampled in seven 10 m² subplots directly surrounding the Malaise traps.…”

“…Additionally, species pools within a 200-m radius were assessed between mid-May and early August 2020 using standardized transect walks in which walking time was proportional to the area percentages of dominant habitat types within the 200-m radius, and walking time was 60 minutes for each plot. Total plant species richness was obtained from all unique species encountered in at least one of the two sampling rounds 66 . This variable was additionally used as predictor in our insect models.…”