Dispersal potential mediates effects of local and landscape factors on plant species richness in maeulsoop forests of Korea

Abstract

Questions: At what spatial scales do plant species with different dispersal potentials respond to landscape characteristics? Do seed rain data support these scale-dependent responses? Does the relative importance of local factors and surrounding landscape characteristics vary according to species dispersal potential? Location: Agricultural landscape, Jinan County, Korea. Methods: Forest plant species from 15 traditional Korean village forests, maeulsoops, were recorded and categorized into short-distance dispersal (SDD) and long-distance dispersal (LDD) species based on dispersal mode. Seed rain samples were collected every 2 wk for 4 mo and identified at the genus level. Local factors (anthropogenic influence and maeulsoop area) were assessed through field surveys and satellite imagery. Landscape characteristics surrounding maeulsoops (forest cover diversity, composition and fragmentation) were assessed at multiple spatial scales using Shannon-Wiener index and PCA. The best regression model at each scale was identified by model selection based on AICc, and the effect of each explanatory variable on species richness was quantified with hierarchical partitioning. Results: A total of 107 forest plant species (39 SDD and 68 LDD) were recorded, and a total of 25 bird-dispersed genera were identified in seed rain samples. Species richness in plant records and genus richness in seed samples were strongly affected by anthropogenic influence and maeulsoop area, respectively. SDD species richness was significantly and positively influenced by total forest cover at small scales of around 150 m. In contrast, LDD species richness was significantly influenced by deciduous forest cover at large scales (1500-3500 m). At these larger scales, the relative importance of landscape characteristics for species richness was higher for LDD than for SDD. These results for LDD species were most notably supported by genus richness in seed rain data. Conclusions: The most important findings of the study highlight that (1) plant species responses to forest cover are scale-dependent; and (2) dispersal potential mediates the effects of local and landscape factors on plant species richness. The results suggest that conservation strategies for native forest species in maeulsoops should not only focus on habitat-specific characteristics but also consider species-specific interactions with surrounding landscapes.