Project Overview

Roads pose significant threats to wildlife populations worldwide, leading to habitat fragmentation and high mortality rates among various species. Mitigation strategies such as wildlife underpasses have been implemented to alleviate these impacts, yet few studies have assessed their effectiveness before and after implementation. We conducted a case study to evaluate the efficacy of wildlife underpasses in mitigating amphibian road mortality. The study area encompassed a 1.3 km stretch of road, where two underpasses were constructed to facilitate amphibian passage. Through a comprehensive survey spanning five years pre- and seven years post-construction, we collected data on amphibian mortality and environmental factors. Linear mixed-effects models were used to assess changes in mortality rates before and after construction using a before-after control-impact design. Our findings indicate a substantial reduction in mortality across the entire amphibian community and for non-arboreal amphibians within the treatment areas post-construction. While arboreal amphibian mortality decreased, the difference wasn't statistically significant. The underpasses effectively facilitated amphibian movement. Overall, our study provides empirical evidence of the effectiveness of wildlife underpasses in reducing amphibian road mortality, highlighting them as a potentially important conservation action.

Objectives

The objectives of this study were 1) to determine if there was a significant decrease in mortality in the treatment areas after the construction of the underpasses; 2) to understand whether underpasses are equally effective for all amphibian species; and 3) to determine whether the underpass wing walls in so-called "buffer" areas impacted mortality more like treatment or control areas.

Dataset Availability

Tags

Status - Completed

Start date: 2010-03-01

End date: 2025-05-01

Study Area

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