David N. Wear

LAND OWNERSHIP AND LAND-COVER CHANGE IN THE SOUTHERN APPALACHIAN HIGHLANDS AND THE OLYMPIC PENINSULA'

Social and economic considerations are among the most important drivers of landscape change, yet few studies have addressed economic and environmental influences on landscape structure, and how land ownership may affect landscape dynamics. Watersheds in the Olympic Peninsula, Washington, and the southern Appalachian highlands of western North Carolina were studied to address two questions: (1) Does landscape pattern vary among federal, state, and private lands? (2) Do land-cover changes differ among owners, and if so, what variables explain the propensity of land to undergo change on federal, state, and private lands? Landscape changes were studied between 1975 and 1991 by using spatial databases and a time series of remotely sensed imagery. Differences in landscape pattern were observed between the two study regions and between different categories of land ownership. The proportion of the landscape in forest cover was greatest in the southern Appalachians for both U.S. National Forest and private lands, compared to any land- ownership category on the Olympic Peninsula. Greater variability in landscape structure through time and between ownership categories was observed on the Olympic Peninsula. On the Olympic Peninsula, landscape patterns did not differ substantially between com- mercial forest and state Department of Natural Resources lands, both of which are managed for timber, but differed between U.S. National Forest and noncommercial private land ownerships. In both regions, private lands contained less forest cover but a greater number of small forest patches than did public lands. Analyses of land-cover change based on multinomial logit models revealed differences in land-cover transitions through time, between ownerships, and between the two study regions. Differences in land-cover transitions between time intervals suggested that addi- tional factors (e.g., changes in wood products or agricultural prices, or changes in laws or policies) cause individuals or institutions to change land management. The importance of independent variables (slope, elevation, distance to roads and markets, and population density) in explaining land-cover change varied between ownerships. This methodology for analyzing land-cover dynamics across land units that encompass multiple owner types should be widely applicable to other landscapes.

Land-Use Changes in Southern Appalachian Landscapes: Spatial Analysis and Forecast Evaluation

ABSTRACT Understanding human disturbance regimes is crucial for developing effective conservation and ecosystem management plans and for targeting ecological research to areas that define scarce ecosystem services. We evaluate and develop a forecasting model for land-use change in the Southern Appalachians. We extend previous efforts by (a) addressing the spatial diffusion of human populations, approximated by building density, (b) examining a long time period (40 years, which is epochal in economic terms), and (c) explicitly testing the forecasting power of the models. The resulting model, defined by linking a negative binomial regression model of building density with a logit model of land cover, was fit using spatially referenced data from four study sites in the Southern Appalachians. All fitted equations were significant, and coefficient estimates indicated that topographic features as well as location significantly shape population diffusion and land use across these landscapes. This is especially evident in the study sites that have experienced development pressure over the last 40 years. Model estimates also indicate significant spatial autocorrelation in land-use observations. Forecast performance of the models was evaluated by using a separate validation data set for each study area. Depending on the land-use classification scheme, the models correctly predicted between 68% and 89% of observed land uses. Tests based on information theory reject the hypothesis that the models have no explanatory power, and measures of entropy and information gain indicate that the estimated models explain between 47% and 66% of uncertainty regarding land-use classification. Overall, these results indicate that modeling land-cover change alone may not be useful over the long run, because changing land cover reflects the outcomes of more than one human process (for example, agricultural decline and population growth). Here, additional information was gained by addressing the spatial spread of human populations. Furthermore, coarse-scale measures of the human drivers of landscape change (for example, population growth measured at the county level) appear to be poor predictors of changes realized at finer scales. Simulations demonstrate how this type of approach might be used to target scarce resources for conservation and research efforts into ecosystem effects.

Ecosystem Management With Multiple Owners: Landscape Dynamics in a Southern Appalachian Watershed

Ecosystem management is emerging as an organizing theme for land use and resource management in the United States. However, while this subject is dominating professional and policy discourse, little research has examined how such system-level goals might be formulated and implemented. Effective ecosystem management will require in- sights into the functioning of ecosystems at appropriate scales and their responses to human interventions, as well as factors such as resource markets and social preferences that hold important influence over land and resource use. In effect, such management requires an understanding of ecosystem processes that include human actors and social choices. We examine ecosystem management issues using spatial models that simulate landscape change for a study site in the southern Appalachian -highlands of the United States. We attempt to frame a set of ecosystem management issues by examining how this landscape could develop under a number of different scenarios designed to reflect historical land-cover dynamics as well as hypothetical regulatory approaches to ecosystem management. Scenarios based on historical change show that recent shifts in social forces that drive land cover change on both public and private lands imply a more stable and a more forested landscape. Scenarios based on two hypothetical regulatory instruments indicate that public land man- agement may have only limited influence on overall landscape pattern and that spatially targeted approaches on public and private lands may be more efficient than blanket regu- lation for achieving landscape-level goals.

Effects of land-cover change on spatial pattern of forest communities in the Southern Appalachian Mountains (USA)

Understanding the implications of past, present and future patterns of human land use for biodiversity and ecosystem function is increasingly important in landscape ecology. We examined effects of land-use change on four major forest communities of the Southern Appalachian Mountains (USA), and addressed two questions: (1) Are forest communities differentially susceptible to loss and fragmentation due to human land use? (2) Which forest communities are most likely to be affected by projected future land cover changes? In four study landscapes, maps of forest cover for four time periods (1950, 1970, 1990, and projections for 2030) were combined with maps of potential forest types to measure changes in the extent and spatial pattern of northern hardwoods, cove hardwoods, mixed hardwoods, and oak-pine. Overall, forest cover increased and forest fragmentation declined in all four study areas between 1950 and 1990. Among forest community types, cove hardwoods and oak-pine communities were most affected by land-cover change. Relative to its potential, cove hardwoods occupied only 30–40% of its potential area in two study landscapes in the 1950s, and oak-pine occupied ∼50% of its potential area; cove hardwoods remained reduced in extent and number of patches in the 1990s. Changes in northern hardwoods, which are restricted to high elevations and occur in small patches, were minimal. Mixed hardwoods were the dominant and most highly connected forest community type, occupying between 47 and 70% of each study area. Projected land-cover changes suggest ongoing reforestation in less populated regions but declining forest cover in rapidly developing areas. Building density in forest habitats also increased during the study period and is projected to increase in the future; cove hardwoods and northern hardwoods may be particularly vulnerable. Although increases in forest cover will provide additional habitat for native species, increases in building density within forests may offset some of these gains. Species-rich cove hardwood communities are likely to be most vulnerable to future land-use change.

The effects of population growth on timber management and inventories in Virginia

Expanding human populations may have important effects on the availability of timber from private lands in the South. To examine the effects of development on timber supply, we compared the density of populations and various site variables with expert opinions on the future location of commercial timberland for a study site in Virginia. Population density is a significant predictor of commercial timberland and resulting probability equations provide a method for adjusting timber inventories. Findings indicate that the transition between rural and urban land use occurs where population density is between 20 and 70 people per square mile. Population effects reduce commercial inventories between 30 and 49% in the study area.

Policy-relevant nonconvexities in the production of multiple forest benefits

Abstract This paper challenges common assumptions about convexity in forest rotation models which optimize timber plus nontimber benefits. If a local optimum occurs earlier than the globally optimal age, policy based on marginal incentives may achieve suboptimal results. Policy-relevant nonconvexities are more likely if (i) nontimber benefits dominate for young stands while the optimal age depends primarily on timber benefits, or (ii) nontimber benefits dominate for mature stands and also determine the optimal age. Nonconvexities may create either temporary or persistent difficulties. Policymakers may improve efficiency by exploiting the relationship between the timber-only optimum and the global optimum.

Challenges to Interdisciplinary Discourse

Many of the worlds critical problems involve human interactions with nature and their long-term implications for environmental quality and the sustainability of resource/ecological systems. These problems are complex-defined by the collective behaviors of people as well as by the structure and function of ecosystems-suggesting that both the social and the natural sciences should focus efforts on dimensions of these problems. The separate efforts of social and natural sciences are unlikely to fully illuminate the fabric of or fashion solutions to environmental problems. Rather, much might be gained by truly interdisciplinary research-endeavors where each constituent discipline informs the investigation of the others and where hypotheses might even be jointly formed. Interdisciplinary research seems the best hope for unraveling the complex interactions between the collective behavior of Homo sapiens and their environment and yielding workable solutions to these problems. If interdisciplinary research is needed to solve critical problems, it seems logical that interdisciplinary research journals would be forthcoming. Indeed it is only with credible platforms for communication that any scientific endeavor can persist. One could go as far as to define a science as simply an ongoing dialog among a group of scientists. Scientists are successful only to the extent that they enter the dialog in a credible fashion, where credibility is certified by the refereed journals of their discipline. For interdisciplinary research (and researchers) to be successful as a science (and scientists), it follows that refereed outlets are needed to certify its discus

Institutional solutions to market failure on the landscape scale

Abstract This paper offers an ecologically-based view of land and land value, building upon the multiproduct nature of ecosystems and upon landscape ecology. The paper questions the ability of markets to create optimal landscapes, even when traditional methods of internalizing externalities are applied, and concludes that attempting a complete valuation of ecosystems is quixotic. Achieving sustainable landscapes requires both sufficient ecological knowledge and institutions capable of overcoming landscape-scale market failure. Accordingly, the paper examines forms of public and private ownership in the United States to assess how well particular institutional conditions might facilitate ecological adaptation there.

Integrating Sustainable Development and Environmental Vitality: A Landscape Ecology Approach

Opportunities for sustaining humans and their environmental systems can be enhanced by examining how socioeconomic and ecological processes are integrated at the landscape level. Landscape properties—such as fragmentation, connectivity, spatial dynamics, and the degree of dominance by habitat types—are influenced by market processes, human institutions, and landowner knowledge as well as by ecological processes. These same landscape properties affect ecological processes that influence species abundance and distribution, as well as the production of goods and services valued by human society. An approach for understanding these complex interactions includes models that simulate (1) land use changes that alter landscape pattern, (2) effects of landscape pattern on species persistence, invasion of exotics, and resource supplies, and (3) dynamic interactions involving possible feedback processes that can alter land uses or landscape patterns. Adaptive management is recommended for using this approach to attain sustainable development where ecological processes operating at micro, meso, and macro scales are integrated.

Modeling the effects of emerald ash borer on forest composition in the Midwest and Northeast United States

The nonnative invasive emerald ash borer (Agrilus planipennis Fairmaire; EAB) has caused considerable damage to the ash (Fraxinus spp.) resource in North America. While there are methods to mitigate, contain, control, or even eradicate some nonnative invasive insects, EAB continues to spread across North America. Considering strong evidence suggesting >99 percent probability of host tree mortality, the loss of the North American ash resource is possible. To examine anticipated effects of EAB on tree species composition, we modeled future spatial and temporal changes in forest composition over the next 50 years with and without ash mortality anticipated from EAB spread. We used U.S. Forest Service Forest Inventory and Analysis (FIA) data, the current extent of EAB in the United States and Canada, estimated spread rate and host mortality data, and a suite of human population, energy, consumption, land use, and economic models to project the future condition of forests in the Midwest and Northeast United States. Our results suggest that in most cases EAB will not have a substantial effect on ecosystem function of future forests measured by FIA because of the replacement of ash by other species. The transition from ash to other species may take many decades, but forests can eventually recover when a variety of associated species replace ash.