Environmental Factors Covey With Plant Diversity-productivity Relationships In The Basin Of Qinghai Lake

The relationship between plant species diversity and primary productivity haslong been a hot topic in biodiversity research. Patterns of biodiversity alongenvironmental gradients are one of the basic issues in biodiversity research.Furthermore, the relationship between species richness and productivity is the mostcontroversial subjects in ecology. Using the actual measurement data of Qinghai Lakebasin from2009to2010, this article is to document the general relationship betweenplant species richness (SR) and above-ground net primary productivity (ANPP) ondifferent spatial scales and the environmental influence on this relationship.We investigated SR–ANPP at100field sites across the widely distributedGrasslands and wetlands of Qinghai Lake basin. Regression Analysis was used to testSR–ANPP relationship among site means. Plot-level data of SR and ANPP wereanalyzed with general linear models (GLMs) and the correlation between SR andANPP was decomposed into covariance components to test the influence of soil salt,soil organic, water content, vegetation, region, elevation and remaining variationamong sites on SR, ANPP and their relationship.The results show that a significant correlation of SR–ANPP relationship wasobserved in the Basin of Qinghai Lake. The SR–ANPP relationship can be positive,negative, unimodal, U-shaped on different scale in Qinghai Lake basin. As shown inour analysis, Environmental factors accounted for a large proportion of variation onthe relationship between SR and ANPP, with soil salt and water content having astrong influence and soil organic matter having a weak effect. The significantcorrelation between plant species richness and productivity decreased when theeffects of soil salt, water content and soil organic matter were removed, and theresidual correlation between SR and ANPP disappeared completely when theremaining variation among sites was also removed. Environmental heterogeneitycaused a significant influence on the relationship between SR and ANPP within sites,environmental heterogeneity factors will gradually reduce with the expansion ofspatial scale and no SR–ANPP relationship would be expected. The potential effectsof environmental conditions on the SR–ANPP relationship on a large spatial scalemay mask direct effects of ANPP on SR potentially operating on a smaller scale.