Activity pattern of arctic reindeer in a predator-free environment: no need to keep a daily rhythm

Loe, Leif Egil; Bonenfant, Christophe; Mysterud, Atle; Severinsen, Torbjørn; Øritsland, Nils Are; Langvatn, Rolf; Stien, Audun; Irvine, R. Justin; Stenseth, Nils Chr.

doi:10.1007/s00442-007-0681-7

Cited by 62 publications

(53 citation statements)

References 58 publications

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“…digestion time, cf. Loe et al 2007) although other factors such as seasonal resource availability (Cederlund 1989), harassment avoidance (Colman et al 2001), temperature (Belovsky 1981), precipitation (Loe et al 2007), or daylight cycles (Pipia et al 2008) may play an important role. Changes in activity rhythms may also occur in response to predation risk (Owen-Smith 1988) or to minimise behavioural interference (e.g.…”

Section: Introductionmentioning

confidence: 98%

Unimodal activity pattern in forest-dwelling chamois: typical behaviour or interspecific avoidance?

et al. 2015

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Daily activity rhythms in mammals are influenced by a range of biotic and abiotic factors. During warm periods, mountain ungulates living in open areas typically show a bimodal pattern of activity rhythms, with peaks at dawn and dusk. To date, however, little is known about the activity patterns of mountain ungulates living in forested habitats and in areas where large predators are present. Using camera traps over a 6-month period between May and October of 2012, we investigated the activity pattern of a chamois population dwelling in the forests of the northern Mount Velebit region (Croatia) and its overlap with the activity patterns of potential predators (brown bear, grey wolf) and competitors (wild boar). Chamois showed a peak of activity between 5:00 a.m. and 7:00 a.m., when 65 % of individuals were photographed. Contrary to previous literature on chamois, we found evidence for a unimodal pattern of activity with a peak in the early morning hours: At a seasonal level, this pattern remained fairly consistent, though the activity at dusk increased in the warmest months. The main peak of activity occurred during periods of decreased activity of potential predators and competitors, and chamois exhibited the least tolerance for overlap with grey wolf. Further studies are needed to clarify whether this pattern is typical of forest-dwelling populations or if it reflects a temporal niche shift, possibly as a strategy to avoid predators.

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Section: Introductionmentioning

confidence: 98%

Unimodal activity pattern in forest-dwelling chamois: typical behaviour or interspecific avoidance?

et al. 2015

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“…When organisms exist at these limits of their ecological tolerance, it can open up the potential for a diversity of flexible, adaptable strategies to promote survival. These strategies are widely utilised in both aquatic and terrestrial ecosystems and range from the biomolecular adaptations of microbes (Pakchung et al 2006) to the timing of foraging in reindeer (Loe et al 2007). Adaptable strategies can also be employed by phytoplankton, and may help overcome the potential environmental constraints encountered within a DCM.…”

Section: Introductionmentioning

confidence: 99%

Complementary ecophysiological strategies combine to facilitate survival in the hostile conditions of a deep chlorophyll maximum

et al. 2011

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In the deep, cooler layers of clear, nutrient-poor, stratified water bodies, phytoplankton often accumulate to form a thin band or "deep chlorophyll maximum" (DCM) of ecological importance. Under such conditions, these photosynthetic microorganisms may be close to their physiological compensation points and to the boundaries of their ecological tolerance. To grow and survive any resulting energy limitation, DCM species are thought to exhibit highly specialised or flexible acclimation strategies. In this study, we investigated several of the adaptable ecophysiological strategies potentially employed by one such species, Chlamydomonas acidophila: a motile, unicellular, phytoplanktonic flagellate that often dominates the DCM in stratified, acidic lakes. Physiological and behavioural responses were measured in laboratory experiments and were subsequently related to field observations. Results showed moderate light compensation points for photosynthesis and growth at 22°C, relatively low maintenance costs, a behavioural preference for low to moderate light, and a decreased compensation point for photosynthesis at 8°C. Even though this flagellated alga exhibited a physiologically mediated diel vertical migration in the field, migrating upwards slightly during the day, the ambient light reaching the DCM was below compensation points, and so calculations of daily net photosynthetic gain showed that survival by purely autotrophic means was not possible. Results suggested that strategies such as low-light acclimation, small-scale directed movements towards light, a capacity for mixotrophic growth, acclimation to low temperature, in situ exposure to low O(2), high CO(2) and high P concentrations, and an avoidance of predation, could combine to help overcome this energetic dilemma and explain the occurrence of the DCM. Therefore, corroborating the deceptive ecophysiological complexity of this and similar organisms, only a suite of complementary strategies can facilitate the survival of C. acidophila in this DCM.

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“…For example, white-tailed deer Odocoileus virginianus (Beier and McCullough 1990) and roe deer Capreolus Capreolus (Cederlund 1989) show a crepuscular activity pattern that is shaped by predators within the area (Leuthold 1977). However, activity patterns in arctic reindeer Rangifer tarandus inhabiting an archipelago free from predation for at least 5,000 years (van der Knaap 1989) do not show distinct peaks in activity at sunrise and sunset (Loe et al 2007). …”

Section: Introductionmentioning

confidence: 99%

Eld’s Deer Translocated to Human-Inhabited Areas Become Nocturnal

Pan

Teng

Cui

et al. 2010

AMBIO

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As human populations expand and nonhuman animals decline, understanding the interactions between people and wildlife is essential. For endangered species, appreciating the effect of human disturbance can be important for their conservation. However, a human disturbance angle is often absent from ecological research, despite growing evidence of the negative impact of nonfatal human interference. Here, we monitored Hainan Eld's deer living within a reserve and translocated animals living amongst villagers. We show that translocated deer deviated from a crepuscular activity pattern and became increasingly nocturnal, and most active when villagers were not. It appears that translocated deer adapted over time to human disturbance and this pattern is similar to that of other species during periods of hunting. People do not pose an actual threat to Eld's deer, but their presence triggered a response akin to predator avoidance and may be interfering with broader aspects of their biology and conservation.

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Activity pattern of arctic reindeer in a predator-free environment: no need to keep a daily rhythm

Cited by 62 publications

References 58 publications

Unimodal activity pattern in forest-dwelling chamois: typical behaviour or interspecific avoidance?

Unimodal activity pattern in forest-dwelling chamois: typical behaviour or interspecific avoidance?

Complementary ecophysiological strategies combine to facilitate survival in the hostile conditions of a deep chlorophyll maximum

Eld’s Deer Translocated to Human-Inhabited Areas Become Nocturnal

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