A Low-Cost GPS GSM/GPRS Telemetry System: Performance in Stationary Field Tests and Preliminary Data on Wild Otters (Lutra lutra)

Background: Despite the increasing worldwide use of global positioning system (GPS) telemetry in wildlife research, it has never been tested on any freshwater diving animal or in the peculiar conditions of the riparian habitat, despite this latter being one of the most important habitat types for many animal taxa. Moreover, in most cases, the GPS devices used have been commercial and expensive, limiting their use in low-budget projects. Methodology/Principal Findings: We have developed a low-cost, easily constructed GPS GSM/GPRS (Global System for Mobile Communications/General Packet Radio Service) and examined its performance in stationary tests, by assessing the influence of different habitat types, including the riparian, as well as water submersion and certain climatic and environmental variables on GPS fix-success rate and accuracy. We then tested the GPS on wild diving animals, applying it, for the first time, to an otter species (Lutra lutra). The rate of locations acquired during the stationary tests reached 63.2%, with an average location error of 8.94 m (SD = 8.55). GPS performance in riparian habitats was principally affected by water submersion and secondarily by GPS inclination and position within the riverbed. Temporal and spatial correlations of location estimates accounted for some variation in the data sets. GPS-tagged otters also provided accurate locations and an even higher GPS fix-success rate (68.2%). Conclusions/Significance: Our results suggest that GPS telemetry is reliably applicable to riparian and even divin

Ranging behaviour and socio-biology of Eurasian otters (Lutra lutra) on lowland mesotrophic river systems

We examined the spatial structure and sociobiology of a native wild population of Eurasian otters (Lutra lutra) on mesotrophic rivers in a mild temperate climate. Radio-tracking of 20 individuals revealed exclusive intra-sexual adult home-ranges. Adult female homeranges (7.5 km, SD = 1.5 km, n = 7) were inversely related to river width (R-adj(2) = 0.68, F-6 = 13.5, P = 0.014) and so appeared to be based on food resources. The aquatic area within adult male home-ranges (30.2 ha, SD = 9.5 ha, n = 5) was greater than that within adult female's (16.8 ha, SD = 7.0 ha) (t(10) = 2.437, P = 0.035), though this result is inconclusive because some males were tracked on oligotrophic rivers. One adult male expanded its range from 10.2 km to 19.3 km within 5 days of the death of the neighbouring male, suggesting that male home-ranges were heavily influenced by conspecifics

Flexible habitat selection paves the way for a recovery of otter populations in the European Alps

Carnivores are threatened worldwide through habitat loss and persecution. Habitat destruction is a major threat for the Eurasian otter. Its populations declined drastically in Europe but are now expanding again, including into the Alps. Here, flood prevention and hydropower have massively altered the riverine landscapes. We evaluated the recovery potential of otters by testing the impact of major factors of habitat transformation and human disturbance on multiple spatial scales. In a hierarchical approach, we investigated spatial use and foraging habitat selection of nine otters in a long-term radiotracking study in the eastern Central Alps. We combined fine scale habitat selection analysis with individual movements by applying a step-selection function approach to the linear river system in a novel way. At home range scale, otters preferred the main riverbeds to abstracted water and tributaries, whereas at fine scale, there was no significant preference for pristine sections within the watercourses. Otters selected for reservoirs in streams with a width smaller than 12 m and otherwise preferred foraging in residual waters and stretches with main discharge. At this stage of recovery, otters show a surprising flexibility in their habitat selection. This is promising for the species' future expansion into former abandoned areas. However, given that the traditional fish stocking regime might contribute to this recovery by providing profitable hunting grounds after stocking events, there is an increased risk of human-wildlife conflicts. Our results demonstrate a high adaptability of a threatened carnivore to altered landscapes and show how this flexible behaviour opens opportunities for recovery

Results of the GLMM model to predict GPS fix-success rate.

<p>Results of the GLMM model to predict GPS fix-success rate.</p

Results of the Riparian GLMM model to predict GPS Location Error.

<p>Results of the Riparian GLMM model to predict GPS Location Error.</p

Performance of GPS devices fitted on wild otters in Southern Portugal, in 2009.

<p>Performance of GPS devices fitted on wild otters in Southern Portugal, in 2009.</p

Results of the Riparian GLMM model to predict GPS fix-success rate.

<p>Results of the Riparian GLMM model to predict GPS fix-success rate.</p

Wild free-ranging female otter (<i>Lutra lutra</i>) fitted with a GPS harness after the release.

<p>Wild free-ranging female otter (<i>Lutra lutra</i>) fitted with a GPS harness after the release.</p

Results of the GLMM model to predict GPS Location Error.

<p>Results of the GLMM model to predict GPS Location Error.</p

Variables used in the evaluation of GPS performance in the stationary tests in Southern Portugal.

<p>Variables used in the evaluation of GPS performance in the stationary tests in Southern Portugal.</p