Direct and indirect effects of linear non-cultivated habitats on epigaeic macroarthropod assemblages

Abstract

Non-cultivated habitats are indispensable ecological spaces within agricultural landscapes that support biodiversity and associated ecosystem services on farmland, thereby contributing to sustainable agriculture. The abundance of taxonomic groups within these habitats serves as a reliable indicator of the diversity levels in epigaeic macroarthropod communities, while the functional groups offer insights into the trophic dynamics of macroarthropods. In recent decades, the impact of non-cultivated habitats on biodiversity within agricultural contexts has received increasing attention. However, few studies have focused on the pathways and factors that influence epigaeic macroarthropod assemblages in different non-cultivated habitats. In this study, Changtu County, a typical agricultural county in the Northeastern Black Soil Region of China, was selected as the study area. The functional and taxonomic groups of epigaeic macroarthropod abundance in different non-cultivated habitats were compared. The structural equation model (SEM) was used to evaluate the direct and indirect effects of non-cultivated habitat type, soil nutrients and vegetation structure reflecting major differences in non-cultivated habitat types on epigaeic macroarthropod assemblages. Our results showed that: (1) linear semi-natural non-cultivated habitats around fields can effectively enhance landscape connectivity. Among these habitats, woodlands (WL), grasslands (GL), and ditches (CD) with high herbaceous vegetation density are usually more favorable for biodiversity conservation in agricultural ecosystems. (2) While dirt roads (DR) and paved roads (PR) may affect the mobility and foraging ability of epigaeic macroarthropods, improving herbaceous vegetation structures along road margins (e.g., planting flowering plants, establishing vegetation buffer zones) can effectively enhance field biodiversity. (3) The characteristics of herbaceous vegetation community are the most important factors affecting the functional and taxonomic groups of epigaeic macroarthropods in different non-cultivated habitats, especially the herbaceous vegetation height (PAH) and species abundance (PAB). In addition, for epigaeic macroarthropods taxonomic groups, non-cultivated habitats affect them not only directly through herbaceous vegetation, but also indirectly through soil organic carbon (SOC). Our results emphasize that in the planning of agricultural landscapes, it is feasible to achieve a harmonious synergy between ecosystem stability and agricultural production through strategic allocation and alteration of herbaceous vegetation structure and soil conditions in different types of non-cultivated habitats.