scholarly journals Deep Learning Resolves Representative Movement Patterns in a Marine Predator Species

2019 ◽  
Vol 9 (14) ◽  
pp. 2935
Author(s):  
Chengbin Peng ◽  
Carlos M. Duarte ◽  
Daniel P. Costa ◽  
Christophe Guinet ◽  
Robert G. Harcourt ◽  
...  
Keyword(s):  
Animal Movement ◽  
Movement Patterns ◽  
Elephant Seal ◽  
Southern Elephant Seal ◽  
Telemetry Data ◽  
Data Set ◽  
Predator Species ◽  
Marine Predator ◽  
Automatic Feature Extraction ◽  
Traditional Approaches

The analysis of animal movement from telemetry data provides insights into how and why animals move. While traditional approaches to such analysis mostly focus on predicting animal states during movement, we describe an approach that allows us to identify representative movement patterns of different animal groups. To do this, we propose a carefully designed recurrent neural network and combine it with telemetry data for automatic feature extraction and identification of non-predefined representative patterns. In the experiment, we consider a particular marine predator species, the southern elephant seal, as an example. With our approach, we identify that the male seals in our data set share similar movement patterns when they are close to land. We identify this pattern recurring in a number of distant locations, consistent with alternative approaches from previous research.

scholarly journals Integrative modelling of animal movement: incorporating in situ habitat and behavioural information for a migratory marine predator

2013 ◽  
Vol 280 (1750) ◽  
pp. 20122262 ◽  
Author(s):  
Sophie Bestley ◽  
Ian D. Jonsen ◽  
Mark A. Hindell ◽  
Christophe Guinet ◽  
Jean-Benoît Charrassin
Keyword(s):  
Process Model ◽  
Animal Movement ◽  
Elephant Seal ◽  
Southern Elephant Seal ◽  
Model Parameters ◽  
Mirounga Leonina ◽  
Marine Predator ◽  
Fundamental Goal ◽  
First Time

A fundamental goal in animal ecology is to quantify how environmental (and other) factors influence individual movement, as this is key to understanding responsiveness of populations to future change. However, quantitative interpretation of individual-based telemetry data is hampered by the complexity of, and error within, these multi-dimensional data. Here, we present an integrative hierarchical Bayesian state-space modelling approach where, for the first time, the mechanistic process model for the movement state of animals directly incorporates both environmental and other behavioural information, and observation and process model parameters are estimated within a single model. When applied to a migratory marine predator, the southern elephant seal ( Mirounga leonina ), we find the switch from directed to resident movement state was associated with colder water temperatures, relatively short dive bottom time and rapid descent rates. The approach presented here can have widespread utility for quantifying movement–behaviour (diving or other)–environment relationships across species and systems.

scholarly journals Movement responses to environment: fast inference of variation among southern elephant seals with a mixed effects model

2018 ◽  
Author(s):  
I. D. Jonsen ◽  
C. R. McMahon ◽  
T. A. Patterson ◽  
M. Auger-Méthé ◽  
R. Harcourt ◽  
...  
Keyword(s):  
Sea Ice ◽  
Movement Patterns ◽  
Elephant Seal ◽  
Mixed Effects ◽  
Foraging Strategies ◽  
Southern Elephant Seal ◽  
Mirounga Leonina ◽  
Movement Model ◽  
Elephant Seals ◽  
Southern Elephant Seals

AbstractLike many species, movement patterns of southern elephant seals (Mirounga leonina) are being influenced by long-term environmental change. These seals migrate up to 4000 km from their breeding colonies, foraging for months in a variety of Southern Ocean habitats. Understanding how movement patterns vary with environmental features and how these relationships differ among individuals employing different foraging strategies can provide insight into foraging performance at a population level. We apply new fast-estimation tools to fit mixed effects within a random walk movement model, rapidly inferring among-individual variability in southern elephant seal environment-movement relationships. We found that seals making foraging trips to the sea-ice on or near the Antarctic continental shelf consistently reduced speed and directionality (move persistence) with increasing sea ice coverage and had variable responses to chlorophyll a concentration, whereas seals that foraged pelagically reduced move persistence in regions where circumpolar deep water shoaled. Given future climate scenarios, pelagic foragers may encounter more productive habitat but sea-ice foragers may see reduced habitat availability. Our approach is scalable to large telemetry data sets and allows flexible combinations of mixed effects to be evaluated via model selection, thereby illuminating the ecological context of animal movements that underlie habitat use.

Stable isotope analyses reveal individual variability in the trophic ecology of a top marine predator, the southern elephant seal

Oecologia ◽  
2011 ◽  
Vol 169 (2) ◽  
pp. 395-406 ◽  
Author(s):  
L. A. Hückstädt ◽  
P. L. Koch ◽  
B. I. McDonald ◽  
M. E. Goebel ◽  
D. E. Crocker ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Trophic Ecology ◽  
Elephant Seal ◽  
Individual Variability ◽  
Southern Elephant Seal ◽  
Stable Isotope Analyses ◽  
Marine Predator ◽  
Isotope Analyses

scholarly journals Revisiting reptile home ranges: moving beyond traditional estimators with dynamic Brownian Bridge Movement Models

2020 ◽  
Author(s):  
Inês Silva ◽  
Matt Crane ◽  
Benjamin Michael Marshall ◽  
Colin Thomas Strine
Keyword(s):  
Home Range ◽  
Animal Movement ◽  
Brownian Bridge ◽  
Movement Patterns ◽  
Estimation Methods ◽  
Home Ranges ◽  
Telemetry Data ◽  
Range Estimation ◽  
Ambush Predator ◽  
Movement Models

AbstractAnimal movement, expressed through home ranges, can offer insights into spatial and habitat requirements. However, home range estimation methods vary, directly impacting conclusions. Recent technological advances in animal tracking (GPS and satellite tags), have enabled new methods for home range estimation, but so far have primarily targeted mammal and avian movement patterns. Most reptile home range studies only make use of two older estimation methods: Minimum Convex Polygons (MCP) and Kernel Density Estimators (KDE), particularly with the Least Squares Cross Validation (LSCV) and reference (href) bandwidth selection algorithms. The unique characteristics of reptile movement patterns (e.g. low movement frequency, long stop-over periods), prompt an investigation into whether newer movement-based methods –such as dynamic Brownian Bridge Movement Models (dBBMMs)– are applicable to Very High Frequency (VHF) radio-telemetry tracking data. To assess home range estimation methods for reptile telemetry data, we simulated animal movement data for three archetypical reptile species: a highly mobile active hunter, an ambush predator with long-distance moves and long-term sheltering periods, and an ambush predator with short-distance moves and short-term sheltering periods. We compared traditionally used home range estimators, MCP and KDE, with dBBMMs, across eight feasible VHF field sampling regimes for reptiles, varying from one data point every four daylight hours, to once per month. Although originally designed for GPS tracking studies, we found that dBBMMs outperformed MCPs and KDE href across all tracking regimes, with only KDE LSCV performing comparably at some higher-frequency sampling regimes. The performance of the LSCV algorithm significantly declined with lower-tracking-frequency regimes, whereas dBBMMs error rates remained more stable. We recommend dBBMMs as a viable alternative to MCP and KDE methods for reptile VHF telemetry data: it works under contemporary tracking protocols and provides more stable estimates, improving comparisons across regimes, individuals and species.

scholarly journals Spatial variation in female southern elephant seal mass change assessed by an accurate non-invasive photogrammetry method

2013 ◽  
Vol 25 (6) ◽  
pp. 731-740 ◽  
Author(s):  
Martin Postma ◽  
Marthán N. Bester ◽  
P.J. Nico De Bruyn
Keyword(s):  
Life Cycle ◽  
Mass Loss ◽  
Marine Mammals ◽  
Three Dimensional ◽  
Elephant Seal ◽  
Southern Elephant Seal ◽  
Marion Island ◽  
Elephant Seals ◽  
Marine Predator ◽  
Three Dimensional Models

AbstractPhysically weighing large marine mammals sequentially over time has presented researchers with a logistical challenge and has severely limited sample sizes. Using a well-established photogrammetry method we developed a simple mathematical method to calculate accurate mass measurements at specific stages in the life cycle of a top marine predator. Female southern elephant seals (n = 23) at Marion Island were sampled sequentially using photogrammetry and three-dimensional models (based on each photogrammetry project) were built for estimation of body mass. Simple equations were applied to obtain mass at critical instances in their life cycle. Marion Island elephant seal mass data was compared to data obtained from physically weighed elephant seals from King George, South Georgia and Macquarie islands. Females from Marion Island are smaller, but their percentage lactation mass loss is similar to females from these other populations. The similarity of percentage mass loss during lactation between different female populations illustrates the accuracy and practicality of the photogrammetric method over a temporal scale. Photogrammetric mass estimation can be used alongside datasets of physically weighed animals and can greatly benefit ecology and life history studies.

Fine- and coarse-scale movements and habitat use by Wood Turtles (Glyptemys insculpta) based on probabilistic modeling of radiotelemetry and GPS-telemetry data

2018 ◽  
Vol 96 (10) ◽  
pp. 1153-1164 ◽  
Author(s):  
D.G. Thompson ◽  
T. Swystun ◽  
J. Cross ◽  
R. Cross ◽  
D. Chartrand ◽  
...  
Keyword(s):  
Habitat Use ◽  
Explicit Knowledge ◽  
Animal Movement ◽  
Low Frequency ◽  
Telemetry Data ◽  
Gps Telemetry ◽  
Data Set ◽  
Glyptemys Insculpta ◽  
Study Results ◽  
Wood Turtles

Understanding animal movement and habitat use is critical for the delineation of habitat requiring protection for species at risk. Defining critical habitat requires studies with observations at a fine enough scale to reflect how animals use and move among habitats and include enough individuals to generalize findings to the population. We present results of a multiyear study on 48 adult Wood Turtles (Glyptemys insculpta (Le Conte, 1830)) from two different populations monitored with low-frequency radiotelemetry and high-frequency GPS telemetry. Results demonstrated the propensity for conventional radiotelemetry to underestimate cumulative distances moved and overestimate the amount of habitat used by Wood Turtles. Together the two data sets demonstrate the propensity for Wood Turtles to remain in close proximity to the river and that some differences in habitat use occur between the sexes; males tended to move parallel to the river, whereas females moved perpendicular to the river. The GPS-telemetry data provided a robust spatiotemporal data set that provided a better understanding of frequently used habitat types and features. Overall, study results suggest that currently delineated areas of protected habitat are likely to be effective in conserving these two populations and provides significantly improved, spatially explicit knowledge that can be used to inform further mitigation efforts if necessary.

scholarly journals Fencing affects African wild dog movement patterns and population dynamics

Oryx ◽  
2021 ◽  
pp. 1-9
Author(s):  
Helen M. K. O'Neill ◽  
Sarah M. Durant ◽  
Stefanie Strebel ◽  
Rosie Woodroffe
Keyword(s):  
Population Dynamics ◽  
Large Scale ◽  
Animal Movement ◽  
Landscape Connectivity ◽  
Ecological Impact ◽  
Movement Patterns ◽  
Wrong Side ◽  
African Wild Dog ◽  
Wild Dog ◽  
Wild Dogs

Abstract Wildlife fences are often considered an important tool in conservation. Fences are used in attempts to prevent human–wildlife conflict and reduce poaching, despite known negative impacts on landscape connectivity and animal movement patterns. Such impacts are likely to be particularly important for wide-ranging species, such as the African wild dog Lycaon pictus, which requires large areas of continuous habitat to fulfil its resource requirements. Laikipia County in northern Kenya is an important area for wild dogs but new wildlife fences are increasingly being built in this ecosystem. Using a long-term dataset from the area's free-ranging wild dog population, we evaluated the effect of wildlife fence structure on the ability of wild dogs to cross them. The extent to which fences impeded wild dog movement differed between fence designs, although individuals crossed fences of all types. Purpose-built fence gaps increased passage through relatively impermeable fences. Nevertheless, low fence permeability can lead to packs, or parts of packs, becoming trapped on the wrong side of a fence, with consequences for population dynamics. Careful evaluation should be given to the necessity of erecting fences; ecological impact assessments should incorporate evaluation of impacts on animal movement patterns and should be undertaken for all large-scale fencing interventions. Where fencing is unavoidable, projects should use the most permeable fencing structures possible, both in the design of the fence and including as many purpose-built gaps as possible, to minimize impacts on wide-ranging wildlife.

Interdependence of social structure and demography in the southern elephant seal colony of Península Valdés, Argentina

2009 ◽  
Vol 25 (3) ◽  
pp. 681-692 ◽  
Author(s):  
Mariano A. Ferrari ◽  
Mirtha N. Lewis ◽  
Miguel A. Pascual ◽  
Claudio Campagna
Keyword(s):  
Social Structure ◽  
Elephant Seal ◽  
Southern Elephant Seal
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