Effects of local characteristics and landscape patterns on plant richness: A multi-scale investigation of multiple dispersal traits

Abstract

Abstract Plant species distributions are determined by various factors (including the dispersal modes and the complex physical environment) across multiple spatial scales, in which the dispersal distance of different dispersal modes and the external environment (including local characteristics and landscape patterns) are closely related. Therefore, understanding the response mechanism of plant species with different dispersal abilities to environmental factors is critical for developing effective landscape management strategies and prioritizing biodiversity conservation efforts at the appropriate scale. In this study, we aimed to explore: (1) the spatial distribution of plant species richness; (2) the spatial scale at which plant species have the strongest response to environment variables (scale of effect); and (3) to identify the key factors that affect the plant species at local and six landscape scales (a 0.5 km, 1 km, 1.5 km, 2 km, 3 km and 4 km-radius circle) considering multiple dispersal traits. We conducted vegetation surveys at 53 sites and classified plant species into three dispersal modes, including biotic dispersal (BD), abiotic dispersal (AD) and autochorous (AT), based on the respective dispersal vector of the seed. We classified land use types into 15 categories and clipped 6 specified radii around each sampling site using ENVI 5.1 and ArcGIS 10.3 software. We applied linear mixed effects models (LMM) to analyze the local and the surrounding landscape variables in predicting plant species richness in Qingshui town of Beijing, China. Our results revealed that the response traits of species to environment factors varied across different scales, proving the existence of scale effect in our study area. The biotically-dispersed (BD) and abiotically-dispersed (AD) species favored structurally complex habitats with greater tree height and cover of herb at the local scale. The area-weighted mean of shape metric (SHAPE_MN) of shrubbery and the euclidean nearest neighbor distance distribution (ENN_AM) of bare land play a major role in determining BD and AD species at large spatial extents, which suggest that the patterns and ecological attributes of patches of these two land use types hinder the migration and colonization ability of species and thus affect the species richness. These results suggest that a multi-scale approach should be encouraged to help guide effective landscape managements in conserving biodiversity for different response traits.