Ground-dwelling Spider Community In Post-fire Forest, Cangshan Mountain, Yunnan

We investigated dynamics of ground-dwelling spider community after fire inmixed broadleaf-conifer forest in Cangshan Mountain, Yunnan Province. Sampling ofground-dwelling spider diversity was carried out in six sites (2,10,18,23and33yearsafter fire, and one unburned site) from2009to2010. A total of13308adult spidersrepresenting28families,66genera, and158species were collected and identified. Themajor results were as follows:(1)Fire disturbance changed the community function structure of ground-dwellingspider in mixed broadleaf-conifer forest in Cangshan Mountain; increased the relativeabundance of hunters; reduced the stability of ground-dwelling spider assemblages andmade it sensitive to the seasonal rainfall and temperature changing.(2)Based on a ‘space-for-time substitution’ sampling by pitfall traps. We found that1)species composition and relative abundance changed dramatically across the six differentfire succession sites;2) the abundance of ground-dwelling spider in the site II wassignificantly higher than other sites, and there was no significant difference in speciesrichness among the six sites;3) ground-dwelling spider community succession could bedivided into3stages by PCoA analysis: site III, IV and V;4) Indicator Species Analysisbased on R language package ‘labdsv’ showed: Sibianor sp.1was the indicator of the firststage, Lycosa graham was the indicator of the second stage, Xysticus sp.2was the indicatorof the third stage, Leptoneta sp.1was the indicator of the control.(3)The surface temperature, humidity and the complexity of vegetation structure arethe main factors that affect the spider species composition in burned forest. In pioneerstage and elastic recovery stage, species composition was mainly affected by the surfacetemperature. But in stable development stage, species composition was influenced bymany abiotic environmental factors together with vegetation structure.(4)Spiders of28families were divided into8guilds: ambush hunters, ground hunters,orb-web、other hunters, Sensing web, Sheet-web, space-web and Specialists. Sheet-webguild with the most abundance, accounted for56.41%of all the specimens, then the groundhunter, which accounted for20.21%. The composition and diversity of guild withoutsignificant change among different sites. Sheet-web, ground-hunter and other hunter guildwith the most species. But CCA (the constrained ordination analyses) showed thatsheet-web, ground-hunter and space-web were the main factors that lead to the change ofspecies composition in different restoration. With the increase of recovery time, spider composition correlated positively with sheet-web and space-web, while negatively withground-hunter.Fire disturbance and subsequent succession changed the ground-dwelling spidercommunity. The habitat selection of indicator could indicate the variability of habitat. Theground spider community in the oldest burned site did not yet resemble the community inthe unburned site, which indicating that the establishment of the climax ground spidercommunity in Cangshan Mountain would take more than three decades. Protection ofnatural forest is still indispensable for biodiversity conservation.