Effects of roads on Castanopsis carlesii seedlings and their leaf herbivory in a subtropical forest in China.

Xiao-Hua Dai,Jia-Sheng Xu,Lu-Rong Cai,Nadir Erbilgin

doi:10.1093/jis/14.1.17

Abstract

The effects of a forest road on Castanopsis carlesii (Hemsley) Hayata (Fagales: Fagaceae) seedlings and their leaf herbivory were investigated in a subtropical forest at Jiulianshan National Nature Reserve, Jiangxi, China. A total of 1124 seedlings, 33949 leaves, 468 leaf mines, and 205 leaf galls were found. Generally, individual numbers, tree heights, and leaf numbers of C. carlesii seedlings became lower with increasing distances from the road. These results might indicate that old seedlings were fewer and survival rate of seedlings was lower in forest interiors. Leaf miners preferred the seedlings close to the forest road, while leaf gallers preferred the seedlings about 2 m from the road. Species diversity of leaf miners was higher in the forest interior area, while species diversity of leaf gallers was higher near the road. However, both leaf miners and leaf gallers decreased in general from the road to the interior forest. There were interspecific differences in the effects of roads on leaf miner species and leaf galler species. The effects of the road on seedlings and insects could be explained by varying microhabitat conditions and different ecological strategies. 摘要

Highlights

Roads have large ecological effects on plants and insects
Litter depth, canopy cover, canopy height, basal area, population density, total biomass, species diversity of native plants, shade-requiring plants, and geophytes are smaller at road edges (Watkins et al 2003; Godefroid and Koedam 2004; Flory and Clay 2009; Avon et al 2010), while understory cover, species diversity of exotic plants, gramnoids, heliphilous plants, disturbance species, and therophytes are higher when adjacent to the roads (Watkins et al 2003; Godefroid and Koedam 2004; Avon et al 2010)
Numbers of C. carlesii seedlings in each 1-m2 area were highest 0.5 m and 6.5 m from the road but lowest 3.5 m from the road; if a subset of squares with large seedling numbers only were considered, seedling numbers seemed to drop with the increasing distances (Figure 2a)

Summary

Introduction

A road can change atmospheric and soil conditions Microhabitat conditions such as pollutants, light, temperature, moisture, and nutrients vary between locations near roads vs far from roads (Spencer and Port 1988; Spencer et al 1988; Angold 1997; Avon et al 2010). Plant individuals have higher body size, biomass, dry weight, nitrogen, water potential, lead, sodium, manganese, leaf number, flower number, shoot length, and shoot diameter on road edges (Spencer and Port 1988; Spencer et al 1988; Lightfoot and Whitford 1991; Martinez and Wool 2006), but individuals have lower resin and sulfate near the roadside (Lightfoot and Whitford 1991). Plants of different species or different ages may show different responses to road-distance effects (Angold 1997; Flory and Clay 2006; Avon et al 2010)

Methods

Results

Conclusion