Land Use Change

The Direct and Indirect Effects of Land Use Change on Wilderness in America

In the next half century America’s population will grow by 50 percent, and so too will the demand for agricultural output. This will make preserving essential ecosystem processes, such as carbon storage, water filtration, and habitat provision, even more challenging. Long-term agricultural production and human well-being both depend on these processes; however the growing demand for food, feed, fuel, and fiber has already led to conversion of natural grasslands and forests to farmlands and reduced the flows of these important non-market ecosystem services. Urbanization of many areas will have even more impacts: spreading cities and towns will lead to more roads, more pollution, and more noise. These large scale land use changes will impact wilderness in ways we are only beginning to understand. Specifically, the impacts will be most acute on wilderness areas that are small in size or adjacent to non-federal lands. In order to protect wilderness areas it is important that we identify where land use change will have the greatest impacts and define what those impacts are, such as degradation of air and water quality, introduction of nonnative species, rise in visitor use pressures, and impacts to species habitat and migration.

We propose to use maps of existing wilderness areas and project land use change by decade for the next 50 years. We will identify how land use change impacts wilderness character and we will provide an assessment of the magnitude of the changes to each area. We will expand on upon the work conducted by Aycrigg et al. (in review), which evaluated the opportunities in the next 50 years for diversifying the ecological representation of the National Wilderness Preservation System by comparing their results to land use change patterns over the next 50 years (Figures 1 and 2). We will also build off the Landscape Assessment effort currently being conducted by The Wilderness Society, which is compiling and analyzing a series of metrics (including biodiversity hotspots, climate change dissimilarities, political viability, and connectivity data) in an effort to determine future impacts on wilderness areas and to identify suitable lands with the highest potential for wilderness area designation. Effects and patterns of future land-use change, both direct and indirect, on designated wilderness will inform not only the impacts to these areas, but also identify new areas with the most potential for new wilderness designation. Areas with wilderness character outside of the National Wilderness Preservation Systems are becoming rare because of pressures from land-use changes (Martinuzzi et al. 2015) and consequently are becoming an important component of a comprehensive strategy to protect biodiversity.

Figure 1. The frequency of percent change in representation of ecological systems with the addition of each land designation category

Graphs of the frequency percent change in representation of ecological systems
A. Percent change from the National Preservation System (NWPS) to NWPS plus all National Park lands (NP) that have yet to be designated wilderness within the National Park Service (NPS); B. Percent change from NWPS plus NP to NWPS plus NP plus land managed as wilderness (MW); C. Percent change from NWPS plus NP plus MW to NWPS plus NP plus MW plus the remaining USFS Inventoried Roadless Areas (IRA); D. Percent change from NWPS plus NP plus MW plus IRA to all land designation categories (i.e., NWPS plus NP plus MW plus IRA plus the remaining BLM roadless lands). For example, the frequency of ecological system representation within the >1-5 percent group when NP lands are added to NWPS lands is 122 (A). Each category is spatially separate from the others.

Figure 2. Percent area change of each ecological system with the cumulative addition of each land designation category to the National Wilderness Preservation System (NWPS)

Maps showing percent change of each ecological system
A. Addition of all National Park lands that have yet to be designated wilderness within the National Park Service (NPS); B. Cumulative addition of lands managed as wilderness that have been studied by Congress or recommended by federal land management agencies, including US Forest Service (USFS), Bureau of Land Management (BLM), and US Fish and Wildlife Service (USFWS), for wilderness designation; C. Cumulative addition of the remaining USFS Inventoried Roadless Areas; D. Cumulative addition of the remaining BLM roadless lands. Each category is spatially separate from the others.

Aycrigg, J.L., J. Tricker, R.T. Belote, M.S. Dietz, L. Duarte, and G.H. Aplet. The next 50 years: opportunities for diversifying the ecological representative of the National Wilderness Preservation System. In review at the Journal of Forestry.
Martinuzzi, S., V.C. Radeloff, L.N. Joppa, C.M. Hamilton, D.P. Helmers, A.J. Plantinga, and D.J. Lewis. 2015. Scenarios of future land use change around United States’ protected areas. Biological Conservation. 184:446-455.