| Abstract |
We address the question of how human activities and infrastructure influence reindeer/caribou's (Rangifer tarandus)
behaviour and habitat use and review studies based on current methodologies. Anthropogenic activities have a direct affect
on Rangifer behaviour through the senses hearing, sight and smell, and all of these are important tools for behavioural risk
assessment. Short term indirect responses, such as habituation, sensitisation, avoidance, and displacement, develop through
neutral, positive or negative associations towards stimulus in terms of Rangifer's ability to experience, learn, and remember.
Long term behavioural responses develop through interaction with predators and, for reindeer, also domestication. A survey
of the literature dealing with behavioural studies reveals that although Rangifer in most cases retreat from anthropogenic
activities, comfort distances (i.e. distances beyond which animal behaviour or activity are not influenced) are relatively short.
In most cases, energetic implications appear moderate and small compared to other natural, biotic influences such as
disturbance (and death) caused by insect and/or predator harassment. Unless obstructing access, physical constructions of
various kinds apparently have limited effects on Rangifer behaviour or habitat use. On the other hand, constructions that
do obstruct or limit access and recreational or other motorized and non-motorized activities appear to have stronger
impacts on avoidance and redistribution of Rangifer. Behavioural effects that might decrease survival and reproduction
include retreat from favourable habitat near disturbance sources and reduction of time spent feeding with resulting
energy depletion over time. Rangifer habitat use, habitat avoidance, and feeding preferences are governed by a complexity
of natural interacting factors. Domestication, habituation and sensitisation are essential in shaping Rangifer's adaptability,
and should be included in future studies on reindeer and caribou responses towards various anthropogenic activities.
Although cumulative effects from human activities are likely, it remains difficult to separate these from natural variations in
Rangifer habitat use and demography. Habitat avoidance towards various human infrastructures and activities is reported,
but most studies reporting relatively far (4-25 km) avoidance distances relied on measurements of range properties and
animal distribution recorded on 1-2 days annually in winter to induce a potential response from the animals and lack
important environmental variables and/or alternative hypothesises. This methodology should be improved in order to enable
identification of correlation versus causation. Studies relying on animal behaviour measurements can more correctly identify
and test responses to various stimuli while also controlling for degree of domestication and other various environmental
variables, but only in a limited time and spatial scale. Furthermore, such studies may not necessarily capture potential
population consequences from disturbances. Thus, there are important weaknesses in the two leading methodologies
(measuring animal behaviour and indirectly mapping regional/population movements and habitat use through measurements
of range properties). To best study Rangifer's responses towards anthropogenic infrastructure and activities, we propose that
the two methodologies be combined and supplied with modern GPS/telemetry. |
