SOIL RESOURCES REGULATE PRODUCTIVITY AND DIVERSITY IN NEWLY ESTABLISHED TALLGRASS PRAIRIE

摘要: In native tallgrass prairie, soil depth and nitrogen (N) availability strongly influence aboveground net primary productivity (ANPP) plant species composition. We manipulated these factors in a newly restored grassland to determine if resources similarly constrain diversity during the initial three years of establishment. Four types experimental plots with six treatment combinations deep shallow at reduced-, ambient-, enriched-N formed basis this study. The responses treatments were examined over years, patterns year 3. did not significantly affect carbon (C) N pools or ANPP diversity. A pulse amendment C added prior planting increased microbial biomass decreased potential mineralization rates effectively reduce throughout Nitrogen declined time nonamended soils as result establishment, but adding fertilizer alleviated increasing immobilization soil. level was lowest highest reduced-N treatment, whereas resulted high productivity, low As result, inversely correlated established com- munities. same mechanism invoked explain under nutrient en- richment old-field ecosystems grasslands (e.g., reduced light production) supported prairie by positive relationship between intercepted light, strong correlation effects on community composition (diversity richness) due primarily species, early successional, nonprairie less than 1% total after These results show that resource are similar young mature grasslands, manipulation limiting establishment can floristic composition, conse- quences for long-term ecosystems.