Assessing the Extent to Which Roadless Areas Complement the Conservation of Biological Diversity

Abstract

We assessed the extent to which inventoried roadless areas (IRAs) on USDA Forest Service lands contain biophysical features that complement the conservation reserve network (e.g., national parks, designated wilderness areas, and wildlife refuges) in the United States. We compared the percentage of land area in IRAs and conservation reserves across three geographic divisions (Alaska, East, and West), 83 ecoregions, 10 elevation zones, and 11 land-cover classes. We also summarized variation in the size class distribution of IRAs.Of the 83 ecoregions evaluated in the United States, 28 have Ͼ12% of their total area in conservation reserves. If IRAs are considered with conservation reserves, the number of ecoregions exceeding the 12% threshold increases from 28 to 32. When only national forest land in the ecoregions is considered, the area of designated wilderness exceeds 12% in 18 of the 45 ecoregions summarized. If IRAs are considered along with designated wilderness, the number of ecoregions exceeding the 12% threshold increases from 18 to 32.On national forest land below 1500 m, 10% is designated wilderness and 18.5% is IRA. Above 1500 m, 20% is designated wilderness and 31.5% is IRA. If IRAs are considered along with designated wilderness, all land-cover classes (except water in the West) would exceed the 12% threshold in Alaska and the West. In the East, only the evergreen forest class would exceed the 12% threshold when IRAs are considered with designated wilderness.Of 462 polygons of designated wilderness in the national forests, 353 are Ͻ20 250 ha, and 25 areas exceed 101 175 ha. If adjacent IRA land is considered along with national forest wilderness, the number of areas Ͻ20 250 ha decreases to 295, and the number of areas Ͼ101 175 ha increases to 45.These results highlight the contribution that IRAs could make toward building a representative network of conservation reserves in the United States. Including these areas as reserves would expand ecoregional representation, increase the area of reserves at lower elevations, and increase the number of areas large enough to provide refugia for species needing large tracts relatively undisturbed by people. Even with the addition of IRAs, many ecoregions in the United States would remain underrepresented in the reserve network, especially in the East.

Connectivity Conservation

“…Wildlife habitat on private lands increases the effective size of the nation's reserve network and thereby enhances both ecosystem integrity and the conservation of biodiversity (DeVelice & Martin, 2001;Loucks et al, 2003;Noss et al, 1999;). The public versus private ownership of core habitat areas that we have identified varies considerably, but over a third of the areas are in management regimes that offer no specified legal protection.…”

USDA Forest Service Roadless Areas: Potential Biodiversity Conservation Reserves

“…These lands represent 31% of the National Forest System or 2.5% of the total U.S. land base (DeVelice and Martin 2001). They would increase the amount of strictly protected land area in the United States in IUCN categories I-III from 4.8 to 8.5%.…”

“…They would increase the amount of strictly protected land area in the United States in IUCN categories I-III from 4.8 to 8.5%. Beyond these most basic statistics, few studies have analyzed the potential contribution of IRAs to biodiversity conservation (Martin et al 2000, DeVelice andMartin 2001). DeVelice and Martin (2001) assessed the extent to which IRAs could contribute to building a representative network of conservation reserves in the United States.…”

Greener transport infrastructure – IENE 2014 International Conference

“…It is therefore only logical to conclude that in certain areas, where these residual effects are not acceptable, construction of transport facilities should be entirely avoided. Such areas need to remain (or become again) roadless to provide sufficient undisturbed space for nature conservation (DeVelice andMartin 2001, Crist et al 2005). Even within Europe, where only small and few roadless areas reside (Selva et al 2011), this need is increasingly recognised.…”