Navigation Links
Road losses add up, taxing amphibians and other animals

WEST LAFAYETTE, Ind. - When frogs hit the road, many croak.

Researchers found more than 65 animal species killed along a short stretch of roads in a Midwestern county. Nearly 95 percent of the total dead were frogs and other amphibians, suggesting that road-related death, or road-kill, possibly contributes to their worldwide decline, a trend that has concerned and puzzled scientists for decades.

The Purdue University study found that habitat along roadsides heavily influences road-kill. More than 75 percent of the carcasses originated alongside a one-mile stretch of road that traverses a wildlife-friendly wetland known as Celery Bog in West Lafayette, Ind.

"On hot summer nights when it rains, there are literally thousands of frogs out there," said Andrew DeWoody, a Purdue researcher who led the study in Tippecanoe County, home to the university.

During the 17-month study, researchers found 10,500 dead animals along 11 miles of roads. Of those, 7,600 were frogs of unidentifiable species and another 1,700 were bullfrogs, said DeWoody, an associate professor of forestry and natural resources.

"In addition to indirect costs of habitat fragmentation, roads have direct costs in terms of animals' lives," he said.

Several steps can be taken to help reduce road-kill, said Dave Glista, study co-author and a Purdue master's graduate who began the study as part of his since-completed thesis measuring roads' environmental impact. For one, development planning should take into account an area's wildlife value. Second, structures to mitigate, limit and prevent road-kill should be explored whenever possible, he said. Options include underpasses, viaducts and overpasses to allow wildlife safe passage, and special fences to keep animals off roads.

"We need to avoid, minimize and mitigate," said Glista, now a scientist with the Indiana Department of Transportation. "As a biologist, I do think we should avoid building roads in wetlands and other wildlife-rich areas. Mitigation structures are worth the cost, as is any measure we can take to minimize our impact on the overall environment."

Scientists estimate that one-third of amphibian species are threatened, and hundreds of species have gone extinct in the past two decades alone. Road-kill adds to numerous factors already implicated in amphibian declines, DeWoody said. These include habitat loss and degradation, disease, pollution, competition from introduced exotic species, and threats posed by climate change.

Frogs, toads and salamanders are all amphibians, a class of four-legged animals known for their moist, scale-free skin. Most species begin life as gilled, water-dwelling creatures before undergoing a dramatic metamorphosis to become four-legged, air-breathing adults, walking or hopping about on land. They serve vital roles in many ecosystems, as consumers of various animals like insects and as a food source for carnivores. To maintain healthy ecosystems, it is vital to limit amphibian losses, DeWoody said.

The study, published online in the latest issue of the journal Herpetological Conservation and Biology, significantly underestimated the number of animals killed because many specimens were scavenged, degraded beyond recognition or moved, DeWoody said. About five times more animals died than could be recorded, he estimated.

The dead included 142 road-killed eastern tiger salamanders, a finding DeWoody said was troubling.

"The absolute number might not look that large, but most of these individuals were mature, up to 10 years old," DeWoody said. "Many of them were gravid, or females bearing eggs on an annual trip to breeding grounds where they often lay 500 to 1,000 eggs. This could make a potentially big difference for the population."

Researchers also found 74 dead northern leopard frogs, a species of special conservation concern in Indiana.

To survive, most amphibians require habitats with running or standing fresh water, in which they lay eggs and begin life. This makes them vulnerable to water pollution and land-use changes like drainage or waterway disruption. Habitats like wetlands and rainforests are in decline worldwide, DeWoody said.

In addition to the toll on frogs and other amphibians, roadways put a wide variety of other animals at risk, he said. Road-killed animals identified in the study included:

  • 79 opossums, the most common mammal;

  • 36 chimney swifts, most common bird;

  • 35 common garter snakes, most common reptile;

  • 43 raccoons; and

  • 4 white-tailed deer.

Glista said he was surprised to find relatively few deer, but he speculated that more may have been hit and were either able to run away or were removed from the roadway.

"We think of deer as being one of the animals more commonly killed on the road, but they actually make up a tiny percentage of the total," he said. "I think that helps put the impact in perspective."

Most road-kill was found along Lindberg Road, which passes through Celery Bog Nature Area in West Lafayette, Ind. Along a one-kilometer (0.6-mile) section, an average of eight amphibians were killed each day, DeWoody said.

Funded by the Joint Transportation Research Program, a partnership of the Indiana Department of Transportation and Purdue, the study focused on road-killed vertebrates, or animals with backbones.

Glista said it took some "backbone" to slowly drive a specially marked vehicle and stop for data samples along four sections of roads in Tippecanoe County twice weekly. During the 496 trips, he said he had close calls with motorists, but always remained careful.

"I didn't want to become one of my own data points," he said.


Contact: Douglas M. Main
Purdue University

Related biology news :

1. Impoverished areas of Africa and Asia face severe crop losses from climate change in 20 years
2. Amphibians respond behaviorally to impact of clear cutting
3. Ancient amphibians left full-body imprints
4. Negligent, attentive mouse mothers show biological differences
5. NYU dental professor discovers biological clock linking tooth growth to other metabolic processes
6. For the paper trail of life on Mars or other planets, find cellulose
7. Lessons from evolution applied to national security and other threats
8. Hungry mothers risk addiction in their adult children
9. Telepathic genes recognize similarities in each other
10. Disrupting common parasites ability to talk to each other reduces infection
11. New drug targets may fight tuberculosis and other bacterial infections in novel way
Post Your Comments:
Related Image:
Road losses add up, taxing amphibians and other animals
(Date:6/22/2016)... ANGELES , June 22, 2016 /PRNewswire/ ... identity management and verification solutions, has partnered ... edge software solutions for Visitor Management, Self-Service ... provides products that add functional enhancements ... partnership provides corporations and venues with an ...
(Date:6/20/2016)... 2016 Securus Technologies, a leading provider ... public safety, investigation, corrections and monitoring announced that ... has secured the final acceptance by all three ... Access Systems (MAS) installed. Furthermore, Securus will have ... installed by October, 2016. MAS distinguishes between legitimate ...
(Date:6/9/2016)... innovation leader in attendance control systems is proud to announce the introduction of fingerprint ... sure the right employees are actually signing in, and to even control the opening ... ... ... Photo ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... ... June 27, 2016 , ... Parallel 6 , ... announced today the Clinical Reach Virtual Patient Encounter CONSULT module which enables ... the physician and clinical trial team. , Using the CONSULT module, patients and physicians ...
(Date:6/27/2016)... June 27, 2016   Ginkgo Bioworks , a ... engineering, was today awarded as one of the ... the world,s most innovative companies. Ginkgo Bioworks is ... the real world in the nutrition, health and ... directly with customers including Fortune 500 companies to ...
(Date:6/24/2016)... ... 2016 , ... Researchers at the Universita Politecnica delle Marche in Ancona combed ... pleural mesothelioma. Their findings are the subject of a new article on the Surviving ... signposts in the blood, lung fluid or tissue of mesothelioma patients that can help ...
(Date:6/23/2016)... /PRNewswire/ - FACIT has announced the creation of ... company, Propellon Therapeutics Inc. ("Propellon" or "the Company"), ... portfolio of first-in-class WDR5 inhibitors for the treatment ... represent an exciting class of therapies, possessing the ... cancer patients. Substantial advances have been achieved with ...
Breaking Biology Technology: