200 research outputs found
Social organization of a solitary carnivore: spatial behaviour, interactions and relatedness in the slender mongoose
The majority of carnivore species are described as solitary, but little is known about their social organization and interactions with conspecifics. We investigated the spatial organization and social interactions as well as relatedness of slender mongooses (Galerella sanguinea) living in the southern Kalahari. This is a little studied small carnivore previously described as solitary with anecdotal evidence for male associations. In our study population, mongooses arranged in spatial groups consisting of one to three males and up to four females. Male ranges, based on sleeping sites, were large and overlapping, encompassing the smaller and more exclusive female ranges. Spatial groups could be distinguished by their behaviour, communal denning and home range. Within spatial groups animals communally denned in up to 33% of nights, mainly during winter months, presumably to gain thermoregulatory benefits. Associations of related males gained reproductive benefits likely through increased territorial and female defence. Our study supports slender mongooses to be better described as solitary foragers living in a complex system of spatial groups with amicable social interactions between specific individuals. We suggest that the recognition of underlying ‘hidden' complexities in these apparently ‘solitary' organizations needs to be accounted for when investigating group living and social behaviour
Monitoring wild animal communities with arrays of motion sensitive camera traps
Studying animal movement and distribution is of critical importance to
addressing environmental challenges including invasive species, infectious
diseases, climate and land-use change. Motion sensitive camera traps offer a
visual sensor to record the presence of a broad range of species providing
location -specific information on movement and behavior. Modern digital camera
traps that record video present new analytical opportunities, but also new data
management challenges. This paper describes our experience with a terrestrial
animal monitoring system at Barro Colorado Island, Panama. Our camera network
captured the spatio-temporal dynamics of terrestrial bird and mammal activity
at the site - data relevant to immediate science questions, and long-term
conservation issues. We believe that the experience gained and lessons learned
during our year long deployment and testing of the camera traps as well as the
developed solutions are applicable to broader sensor network applications and
are valuable for the advancement of the sensor network research. We suggest
that the continued development of these hardware, software, and analytical
tools, in concert, offer an exciting sensor-network solution to monitoring of
animal populations which could realistically scale over larger areas and time
spans
Physics-informed inference of aerial animal movements from weather radar data
Studying animal movements is essential for effective wildlife conservation
and conflict mitigation. For aerial movements, operational weather radars have
become an indispensable data source in this respect. However, partial
measurements, incomplete spatial coverage, and poor understanding of animal
behaviours make it difficult to reconstruct complete spatio-temporal movement
patterns from available radar data. We tackle this inverse problem by learning
a mapping from high-dimensional radar measurements to low-dimensional latent
representations using a convolutional encoder. Under the assumption that the
latent system dynamics are well approximated by a locally linear Gaussian
transition model, we perform efficient posterior estimation using the classical
Kalman smoother. A convolutional decoder maps the inferred latent system states
back to the physical space in which the known radar observation model can be
applied, enabling fully unsupervised training. To encourage physical
consistency, we additionally introduce a physics-informed loss term that
leverages known mass conservation constraints. Our experiments on synthetic
radar data show promising results in terms of reconstruction quality and
data-efficiency.Comment: NeurIPS 2022, AI4Science worksho
Deep Gaussian Markov Random Fields for Graph-Structured Dynamical Systems
Probabilistic inference in high-dimensional state-space models is
computationally challenging. For many spatiotemporal systems, however, prior
knowledge about the dependency structure of state variables is available. We
leverage this structure to develop a computationally efficient approach to
state estimation and learning in graph-structured state-space models with
(partially) unknown dynamics and limited historical data. Building on recent
methods that combine ideas from deep learning with principled inference in
Gaussian Markov random fields (GMRF), we reformulate graph-structured
state-space models as Deep GMRFs defined by simple spatial and temporal graph
layers. This results in a flexible spatiotemporal prior that can be learned
efficiently from a single time sequence via variational inference. Under linear
Gaussian assumptions, we retain a closed-form posterior, which can be sampled
efficiently using the conjugate gradient method, scaling favourably compared to
classical Kalman filter based approachesComment: NeurIPS 2023; camera-ready versio
Exploratory Visual Analysis for Animal Movement Ecology
Movement ecologists study animals' movement to help understand their behaviours and interactions with each other and the environment. Data from GPS loggers are increasingly important for this. These data need to be processed, segmented and summarised for further visual and statistical analysis, often using predefined parameters. Usually, this process is separate from the subsequent visual and statistical analysis, making it difficult for these results to inform the data processing and to help set appropriate scale and thresholds parameters. This paper explores the use of highly interactive visual analytics techniques to close the gap between processing raw data and exploratory visual analysis. Working closely with animal movement ecologists, we produced requirements to enable data characteristics to be determined, initial research questions to be investigated, and the suitability of data for further analysis to be assessed. We design visual encodings and interactions to meet these requirements and provide software that implements them. We demonstrate these techniques with indicative research questions for a number of bird species, provide software, and discuss wider implications for animal movement ecology
Quantifying levels of animal activity using camera-trap data
1. Activity level (the proportion of time that animals spend active) is a behavioural and ecological metric that can provide an indicator of energetics, foraging effort and exposure to risk. However, activity level is poorly known for free-living animals because it is difficult to quantify activity in the field in a consistent, cost-effective and non-invasive way. 2. This paper presents a new method to estimate activity level with time-of-detection data from camera-traps (or more generally any remote sensors), fitting a flexible circular distribution to these data in order to describe the underlying activity schedule, and calculating overall proportion of time active from this. 3. Using simulations and a case study for a range of small to medium-sized mammal species, we find that activity level can reliably be estimated using the new method. 4. The method depends on the key assumption that all individuals in the sampled population are active at the peak of the daily activity cycle. We provide theoretical and empirical evidence suggesting that this assumption is likely to be met for many species, but may be less likely in large predators, or in high latitude winters. Further research is needed to establish stronger evidence on the validity of this assumption in specific cases, however, the approach has the potential to provide an effective, non invasive alternative to existing methods for quantifying population activity levels
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