Behavioral rhythms of an opportunistic predator living in anthropogenic landscapes

Yaiza Parra-Torres,Willem Bouten,Jacopo Aguzzi,Isabel Afán,Francisco Ramírez,Manuela G Forero,Joan Navarro

doi:10.1186/s40462-020-00205-x

Abstract

BackgroundHuman activities have profoundly altered the spatio-temporal availability of food resources. Yet, there is a clear lack of knowledge on how opportunistic species adapt to these new circumstances by scheduling their daily rhythms and adjust their foraging decisions to predicable patterns of anthropic food subsidies. Here, we used nearly continuous GPS tracking data to investigate the adaptability of daily foraging activity in an opportunistic predator, the yellow-legged gull (Larus michahellis), in response to human schedules.MethodsBy using waveform analysis, we compared timing and magnitude of peaks in daily activity of different GPS-tracked individuals in eleven different habitat types, in relation to type of day (i.e., weekday vs. weekend).ResultsDaily activity rhythms varied greatly depending on whether it was a weekday or weekend, thus suggesting that gulls’ activity peaks matched the routines of human activity in each habitat type. We observed for the first time two types of activity as modelled by waveforms analysis: marine habitats showed unimodal patterns with prolonged activity and terrestrial habitats showed bimodal patterns with two shorter and variable activity peaks.ConclusionsOur results suggest that gulls are able to fine-tune their daily activity rhythms to habitat-specific human schedules, since these likely provide feeding opportunities. Behavioral plasticity may thus be an important driver of expansive population dynamics. Information on predictable relationships between daily activity patterns of gulls and human activities is therefore relevant to their population management.

Highlights

Human impacts on the natural environment cause changes in the functioning of natural ecosystems worldwide, which has led a loss of biodiversity [1, 2]
A better understanding of the ecological adaptations of opportunistic species in terms of shaping foraging activity rhythms on human activities is essential to managing the impacts of these activities [9, 17]
While previous research has largely focused on the study of spatial ecology of wildlife species [18, 19] and activity rhythms have been investigated extensively in marine environments [20], studies evaluating how those rhythms match the scheduling of human activities have been less common [17, 21, 22]

Summary

Introduction

Human impacts on the natural environment cause changes in the functioning of natural ecosystems worldwide, which has led a loss of biodiversity [1, 2]. Some species are able to adapt to the predictable dynamics in human-driven food availability, and are capable of taking advantage of highly anthropic scenarios [11, 12]. For many of these opportunistic species, behavioral adjustments represent the first response to altered environmental conditions [13, 14], serving as a foundation of their populations’ expansions in highly impacted areas [15, 16]. We used nearly continuous GPS tracking data to investigate the adaptability of daily foraging activity in an opportunistic predator, the yellow-legged gull (Larus michahellis), in response to human schedules

Methods

Results

Discussion

Conclusion