Understanding a species' feeding ecology is essential for successful management and conservation, because food abundance can influence body mass, survival, reproductive success, movements, and habitat use. We describe annual and seasonal variations in the diet of brown bears Ursus arctos in southcentral Sweden, based on analysis of 527 fecal samples from 1994–1996 and 2000–2001. There was distinct seasonal variation in most of the 26 food items we documented. Ungulates, predominantly moose Alces alces, and insects comprised most of the estimated dietary energy content in spring and summer. Insects were represented almost entirely by ants, of which Formica spp. and Camponotus herculeanus were the most common. During autumn, berries dominated the diet. The most important berry species were bilberry Vaccinium myrtillus, crowberry Empetrum hermaphoditum and lingonberry V. vitis‐idaea. We determined berry availability by inventorying 308 random plots three times for two consecutive years. These three berries occurred with great spatial, seasonal and annual variation in abundance. The bears showed the strongest positive preference for bilberries, a lesser positive preference for crowberries, but no preference for lingonberries. The proportion of berries in the autmn diet was stable between years, but the relative importance of the species changed, indicating that bears switched to crowberries when bilberries were less abundant. The effects of predicted future climatic change might have severe effects on the availability of the berries, which is the only important food available for fat acquisition prior to hibernation.
Animal movement patterns in space and time are a central aspect of animal ecology. Remotely-sensed environmental indices can play a key role in understanding movement patterns by providing contiguous, relatively fine-scale data that link animal movements to their environment. Still, implementation of newly available remotely-sensed data is often delayed in studies of animal movement, calling for a better flow of information to researchers less familiar with remotely-sensed data applications. Here, we reviewed the application of remotely-sensed environmental indices to infer movement patterns of animals in terrestrial systems in studies published between 2002 and 2013. Next, we introduced newly available remotely-sensed products, and discussed their opportunities for animal movement studies. Studies of coarse-scale movement mostly relied on satellite data representing plant phenology or climate and weather. Studies of small-scale movement frequently used land cover data based on Landsat imagery or aerial photographs. Greater documentation of the type and resolution of remotely-sensed products in ecological movement studies would enhance their usefulness. Recent advancements in remote sensing technology improve assessments of temporal dynamics of landscapes and the three-dimensional structures of habitats, enabling near real-time environmental assessment. Online movement databases that now integrate remotely-sensed data facilitate access to remotely-sensed products for movement ecologists. We recommend that animal movement studies incorporate remotely-sensed products that provide time series of environmental response variables. This would facilitate wildlife management and conservation efforts, as well as the predictive ability of movement analyses. Closer collaboration between ecologists and remote sensing experts could considerably alleviate the implementation gap. Ecologists should not expect that indices derived from remotely-sensed data will be directly analogous to field-collected data and need to critically consider which remotely-sensed product is best suited for a given analysis.
Studies of free-ranging wildlife often involve animal capture and fitting of tracking devices. Capturing wildlife may result in behavioral alterations. Thus, there is a need to evaluate the effects of capture on study animals to identify potential biases influencing the research. We assessed the short-term response of 15 GPS/GSM-collared adult female moose (Alces alces (L., 1758)) and immobilization and handling by comparing moose rates of movement and net square displacement before and after recapture. Moose were more active up to 7 h and increased their spatial displacement for 4.5 days after recapture compared with movement patterns before recapture. Opposite to our predictions, moose did not reduced their movement rates after their initial displacement following capture and recovery, i.e., moose did not show any indication for a residual effect. We recommend using individuals as their own controls in analyses of capture impacts to account adequately for individual behavioral differences. We recommend omitting data of at least the first 5 days following capture for analyses of moose movement and distribution.Résumé : Les études sur la faune sauvage en liberté impliquent souvent la capture des animaux et la pose de dispositifs de surveillance. Cette capture de la faune sauvage peut causer des modifications des comportements. Il est donc important d'é-valuer les effets de la capture sur les animaux à l'étude afin d'identifier les erreurs potentielles qui pourraient influencer la recherche. Nous évaluons les réactions à court terme de 15 élans (Alces alces (L., 1758)) femelles adultes munis de colliers GPS/GSM à l'immobilisation et la manipulation en comparant les taux de déplacement des élans et leurs déplacements nets au carré avant et après la recapture. Après la recapture, les élans sont plus actifs pendant une période pouvant atteindre sept heures et augmentent leurs déplacements spatiaux pendant 4,5 jours par comparaison avec leurs patrons de déplacement avant la recapture. Contrairement à nos prédictions, les élans ne diminuent pas leur taux de locomotion après leur déplace-ment initial après la capture et la récupération, c.-à-d. les élans ne montrent aucune indication d'effet résiduel. Nous recommandons d'utiliser les individus comme leurs propres témoins dans l'analyse des impacts de la capture afin de tenir compte adéquatement des différences comportementales individuelles. Nous suggérons d'omettre les données d'au moins les cinq premiers jours après la capture des analyses de déplacement et de répartition des élans.[Traduit par la Rédaction]
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