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Fishes. --- Habitat selection. --- Aquatic biology
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Perch. --- Habitat selection. --- Aquatic biology --- Aquatic biology
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Birds --- Habitat selection. --- Riparian forests --- Migration --- Food --- Habitat
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Animal radio tracking --- Error analysis (Mathematics) --- Habitat selection.
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Black-tailed prairie dog --- Habitat (Ecology) --- Habitat selection --- Habitat. --- Mathematical models.
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Bull trout --- Habitat selection. --- Fishes --- Migration. --- Jarbidge River Watershed (Idaho and Nev.) --- Idaho. --- Nevada. --- United States
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Cutthroat trout --- Salmonidae --- Habitat selection --- Fish populations --- Habitat --- Computer simulation. --- Life cycles
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African swine fever (ASF) is a fatal viral disease that emerged in Kenya, affecting both pigs and wild boars regardless of sex and age. This disease appeared in September 2018 within the province of Luxembourg in Belgium, creating an outburst of contamination within suids. Research and disposal of ASF-infected wild boar carcasses is a crucial activity in order to control the spread of the virus and prevent its persistence in the environment. This study reveals the likely habitats used by these individuals to die based on air temperature. Three temperature-dependent habitat selection models (HSF) were calibrated to investigate the factors influencing the deathbed choices of diseased wild boars. These models were used to generate relative probability of occurrence maps over the study area. The results mainly showed a dependence on wetlands within low to medium slope deciduous forests. As temperature increased, mixed forests were preferred with a mild accentuation of these environmental factors, namely wetter and steeper conditions, showing a slight effect of heat on the selection of death sites. Furthermore, we showed that the number of positive carcasses detected varied seasonally, with more cases discovered in winter and autumn. So, these recommendations should allow the development of strategies to search for carcasses while minimizing the time spent in the field.
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Wildlife population assessment has taken more and more importance through recent years. In Finland, the main used method for population estimation is called “Track counting” and leads to a Kilometric Abundance Index (KAI). As moose takes an essential place in Finnish forestry, it is surveyed each winter thanks to this method. Besides, there is a need in understanding winter habitat selection in order to adjust its management. This study is divided into two main parts: the first one aims to study the impacts of meteorological conditions on daily KAI, the second part focuses on localisation and characterization of winter habitat. For KAI study, three 10km-odd transects have been randomly dimensioned and walked every week from 22nd of January to 23nd of April 2019. New moose’s tracks from last week were counted and a daily KAI was estimated (tracks seen per 10km per day). Best subset method was used to select the model that better predicts KAI according to meteorological parameters. For winter habitat determination, fresh moose’s tracks were followed to localise droppings and resting places. Zones with a high density of found items were considered as preferred habitat. For those habitats, vegetation surveys were conducted, thanks to 5x5m quadrats, both inside and outside the preferred habitats. One-way Anova were achieved in order to highlight differences in terms of vegetation parameters. The built model includes snow depth, snow sinking and daily maximal temperature (r²=0.54). KAI increases with an increasing snow sinking and decreases with the increases of the two other parameters. Results of winter habitat determination have pointed out a difference in trees layer, with more trees in adjacent vegetation (p-value=0.033). In shrub layer, number of individuals is generally higher in preferred habitats (p-value=0.045), with birch (Betula sp.) and pine (Pinus sylvestris) as main found species. Results of this study, both in KAI and winter habitat selection, could help forest manager decision-making process while surveying moose. Depuis les récentes décennies, l’évaluation des populations d’animaux sauvages a pris de plus en plus d’importance. En Finlande, la méthode utilisée pour l’estimation de population animale consiste en un relevé d’un Indice Kilométrique d’Abondance (IKA), en comptant chaque hiver, le nombre de traces dans a neige le long d’un transect. L’élan fait partie des espèces suivies par cette méthode, vu son importance dans les écosystèmes forestiers finlandais. En plus de ces estimations, une meilleure compréhension de la sélection d’habitat hivernaux est primordiale. Les objectifs de cette étude sont divisés en deux sections : la première vise à évaluer l’influence des conditions météorologiques sur l’IKA et la seconde partie s’intéresse à la localisation et caractérisation des habitats hivernaux préférentiels. Pour estimer un IKA journalier, trois transect d’environ 10km ont été aléatoirement reparti sur la zone d’étude et parcouru chaque semaine du 22 janvier au 23 avril 2019. Toutes nouvelles traces d’élans repérés ont été comptées et un IKA journalier a été estimé (nombre de traces vues par 10km par jour). La méthode des best-subset a été utilisé pour déterminer le meilleur modèle permettant de prédire l’IKA selon les différents paramètres météorologiques. Pour l’étude des habitats hivernaux, plusieurs traces fraiches ont été suivis afin de géolocaliser les crottes et couches. Les zones avec une plus grande densité ont été considérés comme habitats préférentiels. Pour ceux-ci, une comparaison de végétation avec la végétation adjacentes a été réalisé par la mise en place de quadrats de relevés. Des Anova à un facteur ont permis d’identifier les différences entre les principales variables mesurées. Le modèle construit permet une estimation correcte de l’IKA (r² =0.54) sur base de la profondeur de neige, de l’enfoncement et de la température maximale journalière. Ainsi, l’IKA augmente avec l’augmentation de l’enfoncement et diminue avec l’augmentation des deux dernières variables. Les résultats de l’étude des habitats hivernaux ont montré une différence significative du nombre d’arbres comptés, en moyenne plus élevés dans la végétation adjacente (p-valeur=0.033). Dans la strate herbacée, il y a en moyenne plus d’arbustes dans les habitats préférentiels (p-valeur=0.045), avec une grande présence de bouleau (Betula sp.) et de pin (Pinus sylvestris). Les resultats de cette étude, que ce soit sur l’IKA ou sur la sélection d’habitats, fournissent des informations concrètes utiles à tout gestionnaire forestier pour la gestion de populations d’élans.
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1) Of particular importance to wildlife conservation and mitigation of the current biodiversity crisis are questions of habitat loss and degradation. In this context, disturbance studies have sought to implement new methods for studying wildlife populations in relation to their environment when subjected to the human footprint. Habitat selection models have proven to be powerful tools for quantifying the impact of human disturbances on wildlife habitat and estimating disturbance parameters influencing spatial and temporal distribution of a species from occurrence data. 2) During the last century, Norway has experienced fast-paced infrastructure development that has resulted in the massive loss of mountain wilderness. In those same mountains live the last remaining populations of wild mountain reindeer (Rangifer tarandus tarandus) in Europe. With pervasive human influence and multiple claims placed on Norwegian mountains, seasonal habitat loss is currently suggested as the main threat for wild reindeer in southern Norway. Accordingly, the Norwegian Government is investing considerable resources into habitat loss assessment, as a critical step to determine if these areas will be able to support viable population units in the future. 3) With the purpose to unravel and quantify the drivers of anthropogenic habitat loss in wild reindeer summer habitat, the present research investigated reindeer habitat use on summer ranges in relation to the human footprint in southern Norway, using existing resource selection functions (RSFs), developed for wild reindeer, and GPS data. Overall, human disturbances were found to induce substantial habitat loss (> 50%) in wild reindeer summer ranges. However, differences could be noted between herds, both in relation to the uneven spatial distribution of the human footprint and the main drivers of anthropogenic habitat loss, which were found to vary between reindeer areas. For the study area as a whole, highest avoidance levels during summertime were induced by the grazing animals from domestic livestock, primarily, as well as by houses of the domestic sector, low traffic summer roads and hiking trails. 4) The present human footprint analysis points out the need for prioritized management and targeted mitigation of herd-specific disturbance sources in wild reindeer ranges. Moreover, it provides key insights for the future prevention of human-reindeer conflicts and will hopefully help to balance wild reindeer conservation with anthropogenic development. This study and the approach it proposes may provide a valuable framework for quantifying the impacts of the human footprint in further biodiversity components, and thus help tackle the loss of natural habitats.
Habitat selection --- Human disturbance --- Zone of influence --- Habitat loss --- Resource selection function --- Cumulative effect --- Human footprint --- Wild reindeer --- Rangifer tarandus --- Sciences du vivant > Sciences de l'environnement & écologie
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