To predict the consequences of environmental change on the biodiversity of alpine wetlands, it is necessary to understand the relationship between soil properties and vegetation biodiversity. In this study, we investigated spatial patterns of aboveground vegetation biomass, cover, species diversity, and their relationships with soil properties in the alpine wetlands of the Gannan Tibetan Autonomous Prefecture of on the Qinghai-Tibetan Plateau, China. Furthermore, the relative contribution of soil properties to vegetation biomass, cover, and species diversity were compared using principal component analysis and multiple regression analysis. Generally, the relationship between plant biomass, coverage, diversity, and soil nutrients was linear or unimodal. Soil pH, bulk density and organic carbon were also significantly correlated to plant diversity. The soil attributes differed in their relative contribution to changes in plant productivity and diversity. pH had the highest contribution to vegetation biomass and species richness, while total nitrogen was the highest contributor to vegetation cover and nitrogen–phosphorus ratio (N:P) was the highest contributor to diversity. Both vegetation productivity and diversity were closely related to soil properties, and soil pH and the N:P ratio play particularly important roles in wetland vegetation biomass, cover, and diversity.

A periphyton-based index for biological integrity was developed to assess the ecological status of lakes and reservoirs in Baiyangdian Watershed, China. Periphyton and environmental surveys were conducted at 20 sites during 2009-2010. A total of 22 surveyed metrics of periphyton, which were classified into 6 categories: biomass groups, community structure, pigment ratios, bacteria diversity, enzyme activities, and metabolism were evaluated in order to understand their responsiveness to environmental degradation. Out of these 22 metrics, six metrics were selected to constitute the periphyton-based index for biological integrity: chlorophyll b, chlorophyll c: chlorophyll a ratio, alkaline phosphatase activity, bacteria dominance, net daily metabolism, and autotrophic index by sensitivity and redundancy analysis. Then the periphyton-based index for biological integrity was verified by an independent validation-site data set. The test results indicated the index could not only discriminate disturbed sites from reference sites, but also be triggered by land use types. The scores of periphyton-based index for biological integrity were significantly correlated with the environmental parameters, especially ammonia nitrogen and total phosphorus. These results suggest that this index may be a potential tool for assessing the ecological status of lakes and reservoirs, polluted mainly by organic contaminants in Baiyangdian Watershed.