Effect of Landscape Elements and Structures on the Acoustic Environment on Wildlife Overpasses Located in Rural Areas

Alicja Sołowczuk

doi:10.3390/su12197866

Abstract

The constantly growing number of motor vehicles increases the biodiversity conservation awareness of the public. To this end, numerous compensation measures are implemented, primarily provision of wildlife crossing infrastructure to guide animals over and under transport routes. There are different design aspects that must be considered in the case of wildlife crossings located in rural areas and in forests. An interdisciplinary approach should be employed for the wildlife crossing design, involving specialists from different fields of science. This article deals with the effect of local landscape elements and structures on the acoustic environment on the wildlife overpasses located in rural areas. Several tests were carried out, covering the levels of traffic, improvements around the existing overpasses and the noise distribution on them. For the final analysis, seven overpasses were chosen, differing in terms of the landscape elements and structures present. Five of them included noise barriers of different shapes and lengths and had a flat approach area. Two crossings did not have noise barriers and the approach areas were located in varied terrain. The analysis of the derived sound maps allowed for the determination of the effect of the different landscape elements and structures on the noise distribution on the overpasses under analysis. Earthen berms aligned with the noise barriers and extending to the length defined by the approach area topography were found to be the most effective noise-reducing measure.

Highlights

The need to make the transport of people and goods faster, more comfortable and safer triggers expansion of the expressway and railroad networks
In Western Europe, the problem of decreasing wildlife populations was recognised by environmentalists already in the 1970s [1,2,3] and geneticists undertook thorough studies on different animal species [3,4,5], which led to establishing a relation between the decreasing numbers of wild animals and landscape fragmentation [6,7]
In the 1990s, effectiveness surveys were carried out for the existing crossing infrastructure, which led to developing the principles of design of crossing structures reconnecting fragmented habitats, recognition of the need to consider the needs of specific species and identification of poor merging of the structures with the surrounding landscape [3]

Summary

Introduction

The need to make the transport of people and goods faster, more comfortable and safer triggers expansion of the expressway and railroad networks. Along a road running for a few hundred kilometres, either existing or under construction, we can expect to find up to a few thousand wild animals, depending on environmental conditions [1,2] This biological variability can be affected by a road having a barrier effect on their existence and leading to fragmentation of habitats. In the 1990s, effectiveness surveys were carried out for the existing crossing infrastructure, which led to developing the principles of design of crossing structures reconnecting fragmented habitats (further called wildlife crossings), recognition of the need to consider the needs of specific species and identification of poor merging of the structures with the surrounding landscape [3].

Adopted Subdivision into Zones of the Overpass Area and Its Surroundings

Sustainable Principles of Design

Assumptions for Acoustic Map Development

Methods of Analysing Noise Maps and the Basic Assumptions of the Study

Findings

Conclusions