Back and forth: day–night alternation between cover types reveals complementary use of habitats in a large herbivore

Abstract

Context The Complementary Habitat Hypothesis posits that animals access resources for different needs by moving between complementary habitats that can be seen as ‘resource composites’. These movements can occur over a range of temporal scales, from diurnal to seasonal, in response to multiple drivers such as access to food, weather constraints, risk avoidance and human disturbance. Within this framework, we hypothesised that large herbivores cope with human-altered landscapes through the alternate use of complementary habitats at both daily and seasonal scales. Objectives We tested the Complementary Habitat Hypothesis in European roe deer (Capreolus capreolus) by classifying 3900 habitat-annotated movement trajectories of 154 GPS-monitored individuals across contrasting landscapes. Methods We considered day-night alternation between open food-rich and closed refuge habitats as a measure of complementary habitat use. We first identified day–night alternation using the Individual Movement - Sequence Analysis Method, then we modelled the proportion of day–night alternation over the year in relation to population and individual characteristics. Results We found that day-night alternation is a widespread behaviour in roe deer, even across markedly different landscapes. Day–night alternation followed seasonal trends in all populations, partly linked to vegetation phenology. Within populations, seasonal patterns of open/closed habitat alternation differed between male and female adults, but not in juveniles. Conclusion Our results support the Complementary Habitat Hypothesis by showing that roe deer adjust their access to the varied resources available in complex landscapes by including different habitats within their home range, and sequentially alternating between them in response to seasonal changes and individual life history.

Body mass mediates spatio-temporal responses of mammals to human frequentation across Italian protected areas

“…A notable deviation from this pattern was represented by the red squirrel, the smallest species of our sample, whose detections were concentrated during daylight, and which strongly responded to human disturbance by decreasing its site use. That diurnal site use decreased with greater extents of open habitat at meta-community level is in line with previous research highlighting a daily shift of space use by mammals between closed and open habitats in relation to exposure to human disturbance and hunting risk, with animals seeking cover under dense forest stands during the peak of human activity at daylight and selecting clearings and open areas during darkness [38,53]. This suggests that the effects of human presence on mammals could be influenced by habitat structure, with habitat suitability therefore changing between daylight, night and twilight hours (e.g.…”

Life history trade-offs in glucocorticoid-mediated habitat selection

“…The delay between consumption and provisioning means milk consumption is not necessarily proportional to the risks the parent has taken, sometimes over long periods of time, to build their energy stores for lactation. One of the ways both lactating mammals and birds avoid risk while acquiring energy is by regularly alternating between foraging habitat and refuge habitats with less forage (De Groeve et al, 2023; Dunning et al, 1992), the latter of which takes time away from foraging and thus eventual energy investment in offspring. As a result, a more universal representation of trade-offs between offspring and parent might be the overall proportion of time parents spend in safer refuge habitats with less forage, versus riskier foraging habitats where they acquire energy to invest some time later in offspring.…”