Traffic Noise Pollution Does Not Influence Habitat Selection in the Endangered Little Bustard

Abstract

Traffic noise is an associated effect of roads, potentially impacting wildlife. In the case of birds, it may alter spatial distribution, behavioural responses and physiological status, frequently masking the acoustic signals of conspecifics and predators. We analyse how road traffic noise affects habitat selection of Little bustard males during the breeding season, when they produce brief territorial snort calls. The study site is in a typical agrarian area in central Spain, markedly affected by traffic noise. A noise map was built using specific environmental noise modelling software. The habitat in the territories of 26 individually-recognisable males (62% of the male population in the study year) was characterised in relation to noise levels, agrarian substrate composition and distance to nearest males. habitat selection models were performed using MaxEnt, and an averaged model of the first 20 significant ones was generated. The noise map revealed high noise pollution levels for the whole study area (range: 50.13-62.35 db). Distance to the nearest male was the most important variable in habitat selection models, so that as distance increased suitability decreased, while the effect of traffic noise was nearly negligible. This lack of traffic noise effect on the habitat selection of Little bustard males might be explained by the low overlap between their snort call frequency and that of traffic noise, but it also suggests a poor capacity by this bird to cope with recent, anthropogenic disturbance. In this respect, noisy but otherwise suitable habitats could be functioning as ecological traps for this rapidly declining species.

Influence of Anthropogenic Noise for Predicting Cinereous Vulture Nest Distribution

“…This could be considered by modeling the type of real disturbance that it is meant to be assessed. For instance, a variety of factors affecting noise exposure predictions need to be contemplated in the case of assessing effects or effect zones on the wider ecosystem for which the modeling of sound propagation has been established as a useful discipline during recent years [66][67][68]. While sound pressure level at a receiver decreases with the distance from the noise source, it is not the only factor influencing the propagation of sound (e.g., type of pavement, trace of road sections, vehicle density, average speed, percentage of heavy vehicles, terrain slope, vegetation coverage, ground absorption, meteorological conditions).…”

Inter-individual consistency in habitat selection patterns and spatial range constraints of female little bustards during the non-breeding season

“…Meanwhile, other studies define the species as tolerant [ 38 , 70 ]. Our results suggest that the little bustard is a flexible species, with some individuals that can exhibit habituation to human disturbances in highly humanized landscapes [ 75 ]. Indeed, some females in the study area positively selected road vicinity areas.…”

Advancing avian road ecology research through systematic review

“…Several grassland species also did not appear to be physically displaced when exposed to traffic noise at roadside environments (Martinez-Marivela et al, 2018;Daniel & Koper, 2019;Spiess et al, 2020), and traffic noise playbacks in quiet areas (Hawkins et al, 2020;Senzaki et al, 2020). At least one recent study reported that several passerine and non-passerine species were attracted to experimental traffic noise (Hennigar et al, 2019), a finding that contradicted those of previous studies.…”