| 英文摘要: | The forests of the southern Appalachian Mountains are home to the most diverse assemblage of trees, amphibians, mollusks, fish, crayfish, millipedes, fungi and other organisms in North America. The steep rugged landscape interacts with a wet climate to create many kinds of habitats, each with its own responses to environmental change. These forests have been continually changing following the last ice age, and humans have played a role in those changes through the activities of Native Americans, colonization by Europeans and frontier farming activities, air pollution associated with acid precipitation, modern land use practices, the introduction of forest diseases and invasive species, fire management policies, and a changing climate. The forests of the Appalachian Mountains contribute ecosystem services such as carbon storage, nutrient cycling, water and air purification, and wildlife habitat. This research seeks to describe and understand how this ecosystem and the services it provides respond to past and ongoing change by using long-term data on forest composition and structure, soil characteristics, climate, and streamflow. The scientists will continue to add to the long-term data and will complete an experiment to assess the impacts of altering the plant community within the streamside corridor. Findings from this research will guide ecosystem restoration and management by land management agencies and Non-government organizations, and also guide the development of water quality policies at multiple levels of governance. Science findings will be communicated to the local community through the Coweeta Listening Project. The proposed research will create education, training and engagement opportunities for diverse scholars, students (middle school, undergraduate, and graduate), and diverse segments of southern Appalachian society including the Eastern Band of the Cherokee.
The southern Appalachian forest biome is responding to a series of past and ongoing disturbances including increasing hydroclimate extremes, higher temperatures, lengthening growing seasons, and continuing exurbanization. Experimental manipulation, observational studies, and regional modeling will be conducted to understand how this ecosystem is responding to past disturbances, land use change, and ongoing climate change. The manipulative rhododendron removal experiment conducted at plot and stream-reach scales will examine, by subtraction, how forest and riparian ecosystems are altered by the observed spread of the native invasive rhododendron. Continued monitoring of forest demography in long-term plots will build upon >20 years of tree demographic data representing >350,000 tree-year. Coupled with diverse spatially extensive climate and soil data and with data collected collaboratively elsewhere, these records will help examine interactions among competition, site characteristics, management, and past disturbance. While empirical work has documented changes in species distributions through time as functions of diverse and interacting physical, biotic, and anthropic factors, this research will rely on distributed ecosystem modeling to examine temporal and spatial ecosystem dynamics across scales. Ecohydrologic modeling using the Regional Hydro-Ecologic Simulation System framework will be used to integrate understanding of fine-scale ecological processes to examine the ecohydrologic and biogeochemical effects of forest change at basin and regional scales. |