Past Research 2002-2008 The 2002 - 2008 research program was an interdisciplinary effort integrating ecological and socioeconomic components across 54,000 km2 of the southern Appalachian Mountains, a bio-geophysical and socioeconomic region in which evolutionary and historical processes converge (Whittaker 1956, Markusen 1987, Barnes 1991, Kretzschmar et al. 1993, Bailey 1996). The research objectives was to advance scientific understanding of the spatial, temporal, and decision-making components of land use and land-use change in the southern Appalachian Mountains over the last 200 years, and forecast patterns emerging in the next 30 years. Our guiding hypothesis was that the frequency, intensity, and extent of land use represents human decision-making in response to socioeconomic and bio-geophysical conditions with consequences that cascade through ecosystems. Our prior research demonstrated that current ecological conditions, including aquatic and terrestrial community structure, nutrient pools, and water quality are not explained without considering past and present land-use. Understanding the causes and consequences of land-use change is a critical research challenge at both national and global scales (Turner et al. 1996, Vitousek et al. 1997, Dale et al. 2000, NRC 2000). From 2002-2008 Coweeta LTER research was organized into three initiatives: C-INITIATIVE I. Characterization of the Socio-Natural Template C-IA. Mapping Long-Term Land-Use Trajectories C-IB. Environmental Gradients C-IC. Disturbance Regimes C-IC1. Dendro-ecological Analyses of Historic Disturbance Regimes C-IC2. Human-disturbance: Analyses of Land-use Choices C-IC3. Impacts of Historic Land-use on River Channels and Floodplains C-INITIATIVE II. Ecosystem Responses to the Socio-Natural Template C-IIA. Baseline Conditions of Stream Fish C-IIB. Understanding the Role of Sedimentation C-IIB1 Sediment Erosion and Yield Through Time C-IIB2. Homogenization of Stream Fish Assemblages C-IIB3. Effects of Suspended Sediments on Fish Foraging Success and Habitat Use C-IIC. Understanding the Role of Organic Matter C-IIC1. Links Among Land-Use Change, Litter Inputs and Litter Processing C-IID. Climatic and Site Controls of Forest Form and Function C-IID1. Controls on Productivity C-IID2. Controls on Overstory Demography C-IID3. Controls on Understory Diversity C-IID4. Controls on Microarthropod Diversity C-INITIATIVE III. Forecasting Ecosystem Responses to Changes in the Socio-Natural Template C-IIIA1. Conceptual and Technical Development of the Forecasting Framework C-IIIA2. Partial Validation of Land-Use Forecasts C-IIIA3. Stream Hazard Site Project C-IIIA4. Effects of Development on Stream Ecology C-IIIA5. Ecosystem Valuation and Social Dynamics Our current research attempts to address ecological and socioeconomic aspects of land-use change while continuing studies of environmental gradients and natural disturbance regimes. This will produce a more complete understanding of ecological dynamics in the southern Appalachian Mountains and make possible the development of reasonable forecasts of its future ecological state. Land use represents a series of decisions and actions carried out by humans to obtain products and/or benefits by using land resources (Veldkamp and Fresco 1996, Foster et al. 1997, Vitousek et al. 1997, Redman 1999b, McConnell and Moran 2001). Despite its pervasiveness, the causes of land use and the consequences of land-use change are poorly predicted by physical laws (Ulanowicz 1986, Pickett et al. 1994, Grove and Burch 1997, Vitousek et al. 1997). For example, recovery of invertebrate and fish assemblages in forested Appalachian streams lags behind the recovery of riparian forests by at least 50 years as a consequence of the complex interaction between human and natural forces (Harding et al. 1998). To achieve a comprehensive understanding of land use and land-use change requires focusing on spatial, temporal, and decision-making components of the process. It also requires resolving among contrasting process parameters: onset vs. duration, distinct land uses vs. site-specific changes, short-term vs. directional change, and past disturbances vs. continuing disturbances (Turner et al. 1990, Bahre 1991, Holling 1992, Russell 1997). By reconstructing when and where particular natural and human events occurred, we can quantify our understanding of spatial heterogeneity in disturbance legacies and the temporal heterogeneity of disturbance trajectories. From these we can calculate the duration and magnitude of consequences at different organizational levels to develop forecast scenarios of future ecological responses. Our integrated scientific research can provide both a description as well as an explanation of the underlying causes of land use and the consequences of land-use change for southern Appalachian ecosystems and society. We continue to build on 21 years of Coweeta LTER research to advance scientific understanding of the spatial, temporal and decision-making components of land use and land-use change in the southern Appalachian Mountains. Our spatial coverage extends from experimental plots to the southern Appalachian social, economic and bio-geophysical conditions with region, while our temporal coverage ranges from hours to centuries. These studies will increase our understanding of the controls on the spatial and temporal variation in ecosystem structure and function.