A new large-scale index (AcED) for assessing traffic noise disturbance on wildlife: stress response in a roe deer (Capreolus capreolus) population

Abstract

Anthropogenic noise is a growing ubiquitous and pervasive pollutant as well as a recognised stressor that spreads throughout natural ecosystems. However, there is still an urgent need for the assessment of noise impact on natural ecosystems. This article presents a multidisciplinary study which made it possible to isolate noise due to road traffic to evaluate it as a major driver of detrimental effects on wildlife populations. A new indicator has been defined: AcED (the acoustic escape distance) and faecal cortisol metabolites (FCM) were extracted from roe deer faecal samples as a validated indicator of physiological stress in animals moving around in two low-traffic roads that cross a National Park in Spain. Two key findings turned out to be relevant in this study: (i) road identity (i.e. road type defined by traffic volume and average speed) and AcED were the variables that best explained the FCM values observed in roe deer, and (ii) FCM concentration was positively related to increasing traffic volume (road type) and AcED values. Our results suggest that FCM analysis and noise mapping have shown themselves to be useful tools in multidisciplinary approaches and environmental monitoring. Furthermore, our findings aroused the suspicion that low-traffic roads (< 1000 vehicles per day) could be capable of causing higher habitat degradation than has been deemed until now.

Social environment modulates investment in sex trait versus lifespan: red deer produce bigger antlers when facing more rivalry

“…Faecal grab sampling was conducted on individual deer from the rectus at the beginning and end of the experiment (March and July). Faecal samples were processed to quantify the metabolite levels of testosterone and cortisol (Iberian red deer 88 ; roe deer Capreolus capreolus [89][90][91] . Frozen faecal samples were dried and milled.…”

Incorporating acoustic objectives into Forest Management Planning when sensitive bird species are relevant

“…Noise modeling was based on the European Directive on environmental noise, END (European Council (EC), 2002). Despite the END being intended for human receivers, it has been successfully adapted to assess the potential impact of anthropogenic noise sources in a variety of wildlife species (Iglesias-Merchan, Diaz-Balteiro & De la Puente, 2016; Iglesias-Merchan et al, 2018; Martínez-Marivela et al, 2018). END (European Council (EC), 2002) establishes that noise maps for a local or national application must be made for an assessment height of four m and the five dB(A) ranges of L den and L night indicators as defined in ISO 9613-2 (1996).…”

“…However, a case study can be found that is based on the response of the Spotted owl to the sound spectrum of a helicopter, which shows that A-weighting matches the owl-weighted function better than the unweighted curve (Pater, Grubb & Delaney, 2009). In the absence of any evidence on this matter, we decided to conduct our research in A-weighted decibels, also because it is possible to find noise metrics in dB(A) with respect to anthropogenic disturbance and wildlife behavioral and physiological responses (Iglesias-Merchan et al, 2018). On the other hand, the use of common tools and frequency weighting may make research gain more options in terms of their future applicability by stakeholders in a variety of fields.…”

“…), which we cannot obviate (Murphy & King, 2010). Thus, the Euclidean distance to the noise source may not be an appropriate index for assessing wildlife disturbance due to human-made noise (Shannon et al, 2016; Iglesias-Merchan et al, 2018).…”

Influence of Anthropogenic Noise for Predicting Cinereous Vulture Nest Distribution

“…Depending on the landscape, there may be sections protected by obstacles (e.g., cutting slopes, constructions), or by the land itself (e.g., embankments, natural hollows) that, even being a few meters from the road edges, are not affected by any traffic disturbance [16]. Modern environmental noise modeling tools studies have allowed researchers to isolate noise from potentially confounding variables, and they have evidenced that noise alone can negatively affect wildlife [17,18]. In this sense, there are a variety of GIS-based modeling resources that provide a huge potential as prediction tools for providing quantitative and spatially explicit assessment of impacts on valued biodiversity components [19].…”