Conservation areas threatened nationally by housing development

December 22, 2009

MADISON -- Conservationists have long known that lines on a map are not sufficient to protect nature because what happens outside those boundaries can affect what happens within. Now, a study by two University of Wisconsin-Madison scientists in the department of forest and wildlife ecology measures the threat of housing development around protected areas in the United States.

In a study published this week in the Proceedings of the National Academy of Sciences (PNAS), Volker Radeloff, an associate professor, and Anna Pidgeon, an assistant professor, looked at housing around every national park, national forest and federal wilderness area in the 48 contiguous states. Using data from the U.S. Census and local sources, they counted housing units built within 1 to 50 kilometers of these reserves, and produced maps and statistics that document the change since 1940 and project forward to 2030.

In 2000, 38 million housing units were within 50 kilometers of these conserved lands, compared to 9.8 million in 1940, and housing was growing faster inside that 50-kilometer range than outside it.

A house's sphere of influence extends beyond its own lot, because housing can encourage the spread of invasive species, alter drainage patterns and foster increased recreational use of the conserved land, which can, ironically, harm wildlife.

Ground-nesting birds are particularly vulnerable to houses and the dogs and cats they contain, as well as to the raccoons, opossum and skunks that are attracted to residential areas, says Pidgeon. The affected species in Wisconsin's northern forest include the ovenbird and black and white warbler.

Many of the effects of housing are unintended, Pidgeon observes. "People are not building houses intending to kill cougars, but that may be the effect if a cougar starts to threaten children and has to be removed."

Migratory animals such as elk need to summer in the mountains and winter in the valleys, Pidgeon notes. "But in the Cascades, the valleys are now filled with orchards and houses."

Another area of concern is light pollution, Radeloff adds. "People don't always think about this, but a lot of wildlife species base their way-finding on the stars or the moon, and a lot of outside light can be confusing and harmful."

The ranges under study, from 1 kilometer to 50 kilometers, were not magic numbers, says Radeloff. "We wanted to capture the range of threats." In general, the closer the house, the higher the impact, he notes. Houses within a kilometer of a preserve can be destroyed by wildfires that start inside the conserved area, "so the manager of a wilderness area might decide to fight a fire instead of letting this natural process run its course. If the house burns, the manager might be in trouble."

One category of development that jumped out of the data was the 940,000 housing units built between 1940 and 2000 in private land inside the boundaries of national forests. These so-called "in-holdings" are surrounded by conserved land and therefore pose a special challenge for wildlife.

The Wisconsin scientists project that housing within 50 kilometers of wilderness areas will have grown 45 percent (10 million units) by 2030 compared to 2000. During the same period, they project housing to grow 52 percent within 1 kilometer of national forests.

The study was supported by the Northern Research Office of the U.S. Forest Service, Radeloff says. "They perceive housing as a big challenge for the management of national forests, because what happens right outside their boundaries is important for their future."

As the Wisconsin scientists envision it, their new maps could be used to help local zoning groups make better decisions about land use, especially when high-value conservation land is a factor. "If you have an important wildlife corridor, it's important to question further density," says Radeloff. "It's no secret that people like living near nature, that's a good thing, but by building there, they may be affecting the very thing they sought out."

Adds Pidgeon, "I was shocked to think that these protected areas aren't doing the job we believe they were doing. There are now rings of housing around national parks like Yellowstone and Yosemite. I don't think it's occurred to people to think about how that may affect biodiversity. These parks, wilderness areas and forests are intended to protect biodiversity, so we need look at what is going on. We are in danger of loving these protected areas to death."
-end-
-- David Tenenbaum, 608-265-8549, djtenenb@wisc.edu

University of Wisconsin-Madison

Related Protected Areas Articles from Brightsurf:

Protected areas help waterbirds adapt to climate change
Climate change pushes species distribution areas northward. However, the expansion of species ranges is not self-evident due to e.g. habitat degradation and unsustainable harvesting caused by human activities.

Scientists reveal urgent solutions for boosting Protected Areas effectiveness
New research published today in Nature identifies the actions needed from governments, private entities, and conservation organisations to boost the effectiveness of Protected Areas and other area-based conservation efforts in protecting biodiversity and providing benefits to people.

More than 90% of protected areas are disconnected
Ongoing land clearing for agriculture, mining and urbanisation is isolating and disconnecting Earth's protected natural areas from each other, a new study shows.

Protected areas can 'double' imperilled species populations
A University of Queensland-led research team has revealed that many endangered mammal species are dependent on protected areas, and would likely vanish without them.

Are protected areas effective at maintaining large carnivore populations?
A recent study, led by the University of Helsinki, used a novel combination of statistical methods and an exceptional data set collected by hunters to assess the role of protected areas for carnivore conservation in Finland.

Protected areas worldwide at risk of invasive species
Protected areas across the globe are effectively keeping invasive animals at bay, but the large majority of them are at risk of invasions, finds a involving UCL and led by the Chinese Academy of Science, in a study published in Nature Communications.

Underprotected marine protected areas in a global biodiversity hotspot
Through the assessment of the 1,062 MPAs in the Mediterranean Sea, covering 6% of the Mediterranean Basin, a research team has shown that 95% of the total area protected lacks regulations to reduce human impacts on biodiversity.

Warming climate undoes decades of knowledge of marine protected areas
A new study highlights that tropical coral reef marine reserves can offer little defence in the face of climate change impacts.

Caribbean sharks in need of large marine protected areas
Governments must provide larger spatial protections in the Greater Caribbean for threatened, highly migratory species such as sharks, is the call from a diverse group of marine scientists including Stony Brook University School of Marine and Atmospheric Sciences (SoMAS) PhD Candidate, Oliver Shipley.

Red coral effectively recovers in Mediterranean protected areas
Protection measures of the Marine Protected Areas have enable red coral colonies (Corallium rubrum) to recover partially in the Mediterranean Sea, reaching health levels similar to those of the 1980s in Catalonia and of the 1960s in the Ligurian Sea (Northwestern Italy).

Read More: Protected Areas News and Protected Areas Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.