conservation.arizona.edu - road impacts

Chen, H. L. and J. L. Koprowski. 2013. Effects of roads on wildlife in Arizona: how far have we Traveled? In Gottfried, Gerald J.; Ffolliott, Peter F.; Gebow, Brooke S.; Eskew, Lane G.; Collins, Loa C., comps. 2013. Merging science and management in a rap

thackerk1 — Thu, 20 Jun 2019 23:23:13 +0000

Authors

Hsiang Ling Chen

John L. Koprowski

Roads are conspicuous and pervasive features of landscapes and represent one of the most significant anthropogenic impacts on natural areas and wildlife. The Madrean Archipelago is defined by natural levels of fragmentation due to geography; however, human population growth and transportation needs threaten to exacerbate levels of isolation in the region. Scientists, as well as transportation and resource management agencies, have increased their concern about road impacts on wildlife. To identify needs of future research and managements, we reviewed 29 road-ecology-related, peer-reviewed publications andgovernmental research in Arizona and compiled geography, focal species, and topic. A taxonomic biastoward large mammals (72%) is evident. Study areas are concentrated along highways and state routes (76%). Despite a prevalence of studies on wildlife road crossing, most research focuses on distribution and movements, whereas impacts at the population and community level are rarely described.

Additional Information

Effects of Roads on Wildlife in Arizona: How Far Have We Traveled?

Date of publication:

2013

Topics

fragmentation

road impacts

large mammals

landscapes

Chen, H. L. and J. L. Koprowski. 2015. Differential effects of roads and traffic on space use and movements of native forest-dependent and introduced edge-tolerant species. PLoS ONE 11:e0148121 doi:10.1371/journal.pone.0148121.

thackerk1 — Thu, 20 Jun 2019 23:06:19 +0000

Authors

Hsiang Ling Chen

John L. Koprowski

Anthropogenic infrastructure such as roads and non-native species are major causes of species endangerment. Understanding animal behavioral responses to roads and traffic provides insight into causes and mechanisms of effects of linear development on wildlife and aids effective mitigation and conservation. We investigated effects of roads and traffic on space use and movements of two forest-dwelling species: endemic, forest-dependent Mount Graham red squirrels (Tamiasciurus hudsonicus grahamensis) and introduced, edge-tolerant Abert’s squirrels (Sciurus aberti). To assess the effects of roads on space use and movement patterns, we compared the probability that a squirrel home range included roads and random lines in forests, and assessed effects of traffic intensity on rate of road crossing and movement patterns. Red squirrels avoided areas adjacent to roads and rarely crossed roads. In contrast, Abert’s squirrels were more likely to include roads in their home ranges compared to random lines in forests. Both red squirrels and Abert’s squirrels increased speed when crossing roads, compared to before and after road crossings. Increased hourly traffic volume reduced the rate of road crossings by both species. Behavioral responses of red squirrels to roads and traffic resemble responses to elevated predation risk, including reduced speed near roads and increased tortuosity of movement paths with increased traffic volume. In contrast, Abert’s squirrels appeared little affected by roads and traffic with tortuosity of movement paths reduced as distance to roads decreased. We found that species with similar body size category (<1 kg) but different habitat preference and foraging strategy responded to roads differently and demonstrated that behavior and ecology are important when considering effects of roads on wildlife. Our results indicate that roads restricted movements and space use of a native forest-dependent species while cre- ating habitat preferred by an introduced, edge-tolerant species.

Additional Information

Differential Effects of Roads and Traffic on Space Use and Movements of Native Forest- Dependent and Introduced Edge-Tolerant Sp

Date of publication:

2015

Topics

non-native species

Mount Graham Red Squirrel

Abert’s squirrels

introduced

road impacts

animal behavior

home range

traffic

Barrier effects of roads on an endangered forest obligate: influences of traffic, road edges, and gaps

thackerk1 — Thu, 20 Jun 2019 22:59:51 +0000

Authors

Hsiang Ling Chen

John L. Koprowski

Habitat fragmentation and destruction caused by development of infrastructure such as roads threaten biodiversity. Roads act as barriers by impeding animal movements and restricting space use. Understanding factors that influence barrier effects is important to discern the impacts of habitat fragmentation and to develop appropriate mitigations. We combined telemetry and demographic data in 2008 to 2012 with remote sensing imagery to investigate barrier effects of forest roads and assess effects of traffic, road edges, and canopy gaps on space use of an endangered, endemic forest obligate, the Mt. Graham red squirrel (Tamiasciurus hudsonicus grahamensis). We mapped low to high traffic roads, road edges, canopy gaps, and random lines in forests to serve as references. We determined if red squirrels included these linear features in their total and core home ranges, and used this metric as an indicator of crossing and preference for habitat adjacent to the linear features. Forest roads acted as barriers regardless of traffic volume and had long-term impacts on animal space use. Animals did not avoid entering roadside areas, and probability of crossing linear features in the forest was not affected by distance to roads. In contrast, greater canopy cover increased probability of crossing, and gaps in canopy impeded animal movements. Higher likelihood of road crossing was associated with more variable tree height and mating activity. We demonstrated that narrow forest roads with low traffic volume were barriers for forest dependent species, and suggest that gap avoidance inhibits road crossings.

Additional Information

Biological Conservation 199:33-40.

Date of publication:

2016

Topics

habitat fragmentation

gap avoidance

forest roads

forest structure

small mammals

road impacts

Research Categories

Behavioral Ecology Disturbance Ecology Sky Islands Threatened and Endangered Species