Fear of the dark? Contrasting impacts of humans versus lynx on diel activity of roe deer across Europe

Abstract

Humans, as super predators, can have strong effects on wildlife behaviour, including profound modifications of diel activity patterns. Subsequent to the return of large carnivores to human‐modified ecosystems, many prey species have adjusted their spatial behaviour to the contrasting landscapes of fear generated by both their natural predators and anthropogenic pressures. The effects of predation risk on temporal shifts in diel activity of prey, however, remain largely unexplored in human‐dominated landscapes. We investigated the influence of the density of lynx Lynx lynx, a nocturnal predator, on the diel activity patterns of their main prey, the roe deer Capreolus capreolus, across a gradient of human disturbance and hunting at the European scale. Based on 11 million activity records from 431 individually GPS‐monitored roe deer in 12 populations within the EURODEER network (http://eurodeer.org), we investigated how lynx predation risk in combination with both lethal and non‐lethal human activities affected the diurnality of deer. We demonstrated marked plasticity in roe deer diel activity patterns in response to spatio‐temporal variations in risk, mostly due to human activities. In particular, roe deer decreased their level of diurnality by a factor of 1.37 when the background level of general human disturbance was high. Hunting exacerbated this effect, as during the hunting season deer switched most of their activity to night‐time and, to a lesser extent, to dawn, although this pattern varied noticeably in relation to lynx density. Indeed, in the presence of lynx, their main natural predator, roe deer were relatively more diurnal. Overall, our results revealed a strong influence of human activities and the presence of lynx on diel shifts in roe deer activity. In the context of the recovery of large carnivores across Europe, we provide important insights about the effects of predators on the behavioural responses of their prey in human‐dominated ecosystems. Modifications in the temporal partitioning of ungulate activity as a response to human activities may facilitate human–wildlife coexistence, but likely also have knock‐on effects for predator–prey interactions, with cascading effects on ecosystem functioning.

Threading the needle: How humans influence predator–prey spatiotemporal interactions in a multiple‐predator system

“…We show that in a human-dominated landscapes, spatial, temporal and spatiotemporal co-occurrence of bears, coyotes, bobcats, adult male deer and fawns across multiple scales changed in nature, with anthropogenically disturbed habitat often related to increased spatiotemporal overlap among species. Our results add to the growing body of work that suggest that as human presence increases, we reduce available niche space for wildlife, causing what can be seen as 'neutral' or 'positive' spatiotemporal associations among species (Bonnot et al, 2020;Haswell et al, 2020;Parsons et al, 2019;Smith et al, 2018;Wang et al, 2015). This reduction in available niche space and increase in spatiotemporal overlap among predators, and predators and prey, has important implications for interspecific interactions like predation and competition.…”

Severity Scoring of Behavioral Responses of Sperm Whales (Physeter macrocephalus) to Novel Continuous versus Conventional Pulsed Active Sonar

“…Effect of anthropogenic disturbances on prey behavior by increasing their level of vigilance to predation is reviewed in [45]. However, the corollary, i.e., that increased predation risk can influence the degree of alert/reaction to other stressors such as anthropogenic disturbances or other potential predators, has been much less considered (e.g., in ungulate species: [46,47]). In the marine environment, herring (Clupea harengus) exhibit stronger antipredator responses to visual predator cues when previously exposed to predator sounds [48].…”

The Role of Animal Cognition in Human-Wildlife Interactions

“…Perhaps the more common (though not mutually exclusive) scenario is that animals living in urban environments adjust their behavior over time via learning, or other forms of behavioral plasticity ( Sol et al, 2013 ). These behavioral adjustments may take many forms, including altering habitat use to minimize contact with people ( Duarte et al, 2011 ; Bonnot et al, 2020 ), or becoming more tolerant of human presence through habituation and/or risk allocation ( Lima and Bednekoff, 1999 ; Rodriguez-Prieto et al, 2009 ). Whether animals tolerate or avoid human disturbance is likely to depend on the nature of their interactions with people.…”

“…For example, the extent to which animals tolerate or avoid humans is likely to influence habitat use ( Rodríguez-Prieto and Fernández-Juricic, 2005 ; Mallord et al, 2007 ), leading to local changes in species abundance and richness ( Mallord et al, 2007 ; Bötsch et al, 2017 , 2018 ). As a result, these changes may modify interactions between predators and prey (e.g., Berger, 2007 ; Gaynor et al, 2018 ; Bonnot et al, 2020 ). Changes in predator-prey interactions may have wider population-level impacts: for instance, puma ( Puma concolor ) respond to human disturbance by reducing feeding time at individual kills, but appear to compensate for this reduced energy intake by killing more deer in areas of higher human population density ( Smith et al, 2015 ).…”