A study published in the Proceedings of the National Academy of Sciences finds that housing growth in and near federally restricted areas far outstrips nationwide housing growth. The study by Radeloff and 7 others looked at housing in and around wilderness areas, national parks, and national forests.

In several previous posts I reported that developed areas in the United States are sprawling. In Land Use Change in Missouri I discussed data that showed the increase in developed land, often at the expense of vacant or forested land. In Converting Land From Its Natural State I reported that wetlands and forests are particularly good at providing certain ecological services that are necessary for life on earth. Federally protected areas are supposed to function something like modern “Noah’s Arks,” protecting especially important natural resources and ecosystems.

Housing doesn’t have to occur within the boundaries of a protected area to impact it. Even though it is outside the protected area, it increases pollution, fragmentation, severing of wildlife corridors, runoff, recreational use, etc.

It seems reasonable to assume that the impacts of nearby development would be less significant for large tracts that have significant internal space far from their boundaries (like Yellowstone National Park, for instance), and more significant for smaller protected areas, such as the fragmented tracts of the Mark Twain National Forest in Missouri, where no part of the tract is far from a boundary. Thus, this issue may be of particular relevance for Missouri.

The first graphic at right shows two maps. The upper one shows the percentage growth between 1940 and 2000 in the number of housing units in or within 50 km. of protected lands. The lower one shows the growth in the raw number of housing units within 50 km. Housing has increased more than 400% near some protected areas in the West. In Missouri, housing in protected areas has increased 100-200%. But in terms of raw numbers, it has grown by more than 400,000 units.

Fifty km. is a pretty wide buffer. For instance, Springfield and Columbia are within 25 km. of Mark Twain National Forest, so their growth would be included in the count. On Google Earth I was able to use the Polygon Tool to create a map that gives a rough idea of how much of Missouri would be covered by a 50 km. boundary around all of the forest’s units. The map is at right. Just eyeballing it, it appears that about 1/3 of the state would be covered, plus portions of Arkansas and Illinois.

Tracts of Mark Twain National Forest With A 50-Mile Buffer

The increase in housing near protected lands that were far away from metropolitan areas in 1940 may represent housing near land that is attractive because it is protected. Examples might include the Sierra Nevada mountains, Northern California, and Northern Idaho-Northern Montana. But in Missouri, the trend may not be only about the attractiveness of protected land per se. It may also be about the growth of urban areas, the expansion of developed land everywhere, the incessant pressure that comes from a growing population and from sprawl.

More on this in my next post.

Sources:

Radeloff, V.C., Stewart, S.I., Hawbaker, T.J., Gimmi, U., Pidgeon, A.M., Flather, C.H., Hammer, R.B., and Helmers, D.P. (2010). Housing Growth in and Near United States Protected Areas Limits Their Conservation Value. Proceedings of the National Academy of Sciences, 107, (2), 940-945, http://www.pnas.org/content/107/2/940.full.pdf+html.