Responses of ground beetle (Coleoptera: Carabidae) assemblages to stand characteristics and landscape structure in riparian poplar forests

Abstract

1. Many carabid beetles are among the most important biocontrol agents and are biological indicators of environmental change, although relatively little is known about how local and landscape factors affect forest ground beetle assemblages. Understanding such effects of multi-scale environmental drivers on ground beetles can promote carabid diversity and conservation.2. Ground beetles were sampled by pitfall trapping in 40 poplar forest stands (sampling plots) along the Irtysh River in Northwestern China. We investigated responses of carabid activity density, species diversity and functional diversity (FD) to stand characteristics and surrounding landscape structure (the overall diversity and percentage cover of vegetation productivity classes in the surrounding area of each sampling plot based on normalised difference vegetation index).3. While carabid activity density only responded positively to the overall diversity of vegetation productivity classes, carabid species diversity was positively associated with this landscape factor as well as vegetation cover but negatively associated with the nearest distance from sampling plot to the river. Only carabid FD responded significantly to percentage cover of vegetation productivity classes, showing a positive correlation with the proportion of medium vegetation productivity. Furthermore, overall carabid FD declined with increasing tree canopy cover. 4. Our results can help predicting spatial patterns of ground beetles according to landscape diversity and proportions of surrounding vegetation types and improve the design of conservation strategies (such as altering canopy cover) of carabids, especially forest specialist species. Any forest management strategies for promoting carabid diversity should consider the pervasive effects of landscape composition and configuration besides local stand characteristics.

Restoring tree species mixtures mitigates the adverse effects of pine monoculture and drought on forest carabids

“…These positive changes appear to have been further exacerbated by decreasing tree density, as carabid abundance increased in these mixed forests when the total number of trees per plot was reduced from 100 to 66 and 40. This positive effect of reduced forest density on carabid abundance is consistent with previous studies (Ings & Hartley, 1999;Lange et al, 2014;Wang et al, 2021;Yi & Moldenke, 2005), showing that that greater canopy openness could promote more abundant or diverse understory vegetation, providing more hunting and foraging niches and protection from predators and desiccation. This would also explain why the reduction in tree density had no effect in pure stands of maritime pine (Pp100 vs. Pp50), which shaded the understory vegetation even at the reduced density.…”

“…This effect of canopy cover on the abiotic conditions of the understorey is known to favour forest‐dwelling carabid beetles, while it disadvantages open‐habitats species that prefer drier conditions (Ings & Hartley, 1999; Negro et al, 2014). This generally results in an overall decrease in species richness and functional diversity of carabid beetles as tree density or canopy closure increases (Lange et al, 2014; Niemelä et al, 1996) due to the loss of these open‐habitat species (Spake et al, 2016; Wang et al, 2021). However, daily temperature and amplitudes of vapour pressure deficit also decrease with increasing stand structural complexity (Ehbrecht et al, 2017), which has been shown to be greater in mixed species forests.…”

Bridging the Gaps: Exploring Aquatic–Terrestrial Connectivity through the Trait-Based Ecology of Riparian Predatory Arthropods

“…Landscape land use changes and vegetation management influence the functional dispersion of riparian ground beetle communities. The highest value of this component was found in landscapes with medium vegetation productivity [111]. The only study of riparian spider FD found functional evenness to be the most sensitive metric to environmental changes, slightly increasing with urbanization.…”

“…Functional dispersion is the most used FD component for the research of riparian predatory arthropods. It has been studied in response to the following: flooding [17,24], riparian bank type (i.e., cut-off or slip-off banks) [25], riparian vegetation characteristics (i.e., natural or managed vegetation; % of vegetation cover) [25,111], and land use change (i.e., landscape vegetation productivity index) [111]. Carabid functional dispersion, used to evaluate functional redundancy, was lower in flooded habitats [17,24], demonstrating the increased flood resilience of local communities.…”

“…Riparian vegetation management has been found to reduce the functional dispersion of carabid communities [25,111], as has densely forested habitats [111]. Landscape land use changes and vegetation management influence the functional dispersion of riparian ground beetle communities.…”