Movement Ecology最新文献

Background: GPS telemetry has become the norm for the tracking of large-bodied bird species, whereas management and conservation of populations often rely on low-tech methods such as capture-mark-resighting (CMR). Direct evaluations of the comparability of the respective outcome from these methods remain rare despite being crucial for comparative studies and management decisions. Here, we investigated whether GPS tracking and CMR lead to same conclusions about seasonal migration and year-round space use. We chose greylag geese (Anser anser) as a study species, for which a long record of both coded neckband reports and GPS tracking are available, and whose management relies on CMR data.

Methods: Our data set was comprised of neckband reports and GPS tracks collected for birds from five capture sites in Sweden (n = 665 neckband birds; n = 156 GPS collar birds). We evaluated the similarity of movement metrics and year-round space use derived from continuous-time movement models and auto-correlated kernel density estimators. We further quantified overlap of spatial range estimates between tracking methods for the breeding period and the wintering season. We approximated spatial observation bias by contrasting range estimates estimated with and without the use of a debiasing algorithm.

Results: We found that estimates of space use derived from CMR and GPS tracking were in general agreement: average year-round space use for most individuals was similar even if means among tracking methods differed among all individuals per method (CMR: [Formula: see text]; GPS: [Formula: see text]), and mean overlap of range estimates for summer and winter did not differ depending on whether the comparison was with the same, or differing tracking methods. Movement metrics differed considerably between methods whenever the CMR data captured behaviour at a different temporal scale than GPS (position & velocity autocorrelation), and else in agreement with GPS tracking (periodicity).

Conclusion: Our study suggests that the historical and current use of coded neckband data for greylag goose management decisions is appropriate regarding space use of migratory greylag geese in Europe. Understanding whether the existing reporter network can capture changes to the migratory behaviour of greylag geese including short-stopping of migration will however require additional in-depth analyses.

Termite nests widely vary in size and complexity across species. While nest structure reflects the social organisation of termite colonies, its impact on individual-level behaviour is unknown. Here, we show that termite worker movements are strongly correlated with their nesting strategies. We compared one-piece nesters, whose colony life cycle is completed within a single piece of wood serving as nest and food, to foragers, which make colonies exploiting resources spanning several wood items. Our observations of worker movements revealed that one-piece nesters moved significantly less than foragers. The distributions of movement duration were also different, with foragers showing a tendency to sustain locomotion once initiated, while the locomotion of one-piece nesters stopped within a short period. On the contrary, the distributions of pausing duration were broadly consistent across species, with a notable exception in C. formosanus. Spatial analyses further showed that foragers exhibited stronger wall-following behavior and traversed the arena center more straightly than one-piece nesters. Thus, nesting strategies are reflected not only in movement activities but also in the spatial exploration of novel environments. These findings provide a new framework for understanding how nesting strategies drive the evolution of movement patterns across social species.

Understanding species responses to anthropogenic disturbance is fundamental to ecology and conservation. However, behaviour and inter-individual variation in habitat selection can complicate our understanding of population-level responses to human disturbance, and the initiatives we design to address them. We use a dataset of 601,000 locations from 42 GPS tracked individuals of three sympatric species - king (n = 32), turkey (n = 5) and black vultures (n = 5) - in Costa Rica to explore behaviour-specific habitat selection in a mixed forest-agriculture landscape. We separate the movement data into three key behaviours (flight, feeding and roosting), and then compare their habitat selection preferences using a species-specific generalised mixed modelling framework. We find that the disturbance sensitive king vultures typically prefer mature forest to anthropogenically modified habitats when flying or roosting, however, the difference in relative strength of selection disappears in relation to feeding. These patterns likely reflect king vultures selecting to feed in agricultural landscapes where dead livestock such as cattle are abundant. We find strong evidence for individual heterogeneity in the degree to which they select for livestock pasture as feeding sites, suggesting repeatable individual-variation in foraging tactics. We also found a strong reduction in habitat selection for all behaviours as the distance to contiguous high-quality habitat increases, showing the reliance on tracts of contiguous mature forest for this species. In comparison, the disturbance tolerant species showed idiosyncratic responses to modified habitats, whereby black vultures selected mature forests for flight, but disturbed forest and grassland margins for feeding and roosting, and turkey vultures selected disturbed forest over mature forest and grassland margins for all movement behaviours. These findings represent the first GPS derived habitat selection study of king vultures, the apex obligate scavengers in lowland neotropical habitats and the first multispecies, guild-level, habitat selection analysis of vultures in the lowland neotropics. As expected, we find that king vultures have a stronger affinity to mature forests than their disturbance tolerant counterparts, however cattle farming is likely strongly subsidising some individuals' diets. Despite this, the marked reduction in king vulture habitat use with increasing distances from contiguous mature forests suggests the existence of a disturbance threshold, whereby the carrying capacity of king vulture populations may be reduced in highly anthropogenically modified landscapes.