Forest roads negatively affect wildlife

Results suggest forest roads might harm animals well beyond road boundaries

Roads used for natural resource extraction, such as logging or oil and mineral removal, often run through otherwise undisturbed forested areas. A new study led by a University of Missouri-Columbia researcher has found that these forest roads, whether in current use or abandoned years earlier, negatively impact wildlife populations.

"Our results may exemplify a problem created by current and past land use activities in all forested regions, especially those related to road building for natural-resource extraction," said Ray Semlitsch, Curators' professor of Biological Sciences and lead investigator in the study. "The problem we revealed points to a potential failure of forest managers and policy makers to realize that the effect of roads reaches well beyond their boundaries and that abandonment or the decommissioning of roads does not mean detrimental ecological effects disappear. Current management decisions have significant repercussions for generations to come."

The study monitored salamander populations in the southern Appalachian Mountain region in the Nantahala National Forest in North Carolina. Semlitsch and his co-investigators found that salamander abundance was negatively impacted for approximately 35 meters on both sides of relatively narrow, low-use roads currently in use. They also found that salamander abundance was reduced in areas near roads that had been abandoned.

"Woodland salamanders are small, lungless, sedentary and strongly dependent on cool, moist forest habitat, which makes them excellent indicators of environmental stress or change," Semlitsch said. "Our study found that forest roads negatively impact salamanders and probably other forms of wildlife as well. Extraction of timber 80 years ago has created a significant ecological 'footprint' in a forest that supersedes regeneration of the forest itself. Assuming current timber management practices harvest trees at intervals of 80 to 100 years, footprints of logging roads from past harvests will not be gone before a new footprint is laid down, and effects will accumulate over time, eventually fragmenting forests into ever-smaller patches of suitable habitat."

The study used a model to predict how much of the national forest was potentially unsuitable for salamanders due to roads and road-effect zones around roads. Using a relatively conservative road-effect size of 35 meters on each side of a road, the study found that 28.6 percent of the entire district was unsuitable habitat for the salamanders; using a higher estimate of 60 to 80 meters based on their work and others, the percentage of unsuitable forest habitat rose to between 36.9 and 42.8 percent.

Prior to this study, there was little data about the ecological impact of low-use and abandoned roads in heavily forested areas. Collaborators in the study included former MU graduate student Travis J. Ryan of Butler University; Kevin Hamed of Virginia Highlands Community College; Matt Chatfield of the University of Michigan; Bethany Drehman; Nicole Pekarek of Asheville-Buncombe Technical Community College; Mike Spath of Highlands Biological Station; and Angie Watland of the Clinch Valley Program, which is part of The Nature Conservancy. The study will be published in the journal Conservation Biology.

Links:

Raymond Semlitsch lab
Division of Biological Sciences

article (available if you have a password for the journal or if your institution is a subscriber)

Matt Chatfield, University of Michigan Museum of Zoology
Kevin Hamed, Virginia Highlands Community College
Nicole Pekarek, Asheville-Buncombe Technical Community College
Travis J. Ryan, Butler University
Mike Spath, Highlands Biological Station
Angie Watland, Clinch Valley Program, The Nature Conservancy