Beyond Optimal Searching: Recent Developments in the Modelling of Animal Movement Patterns as Lévy Walks

Author(s):  
Andy Reynolds
2010 ◽  
Vol 7 (53) ◽  
pp. 1753-1758 ◽  
Author(s):  
Andy M. Reynolds

For many years, the dominant conceptual framework for describing non-oriented animal movement patterns has been the correlated random walk (CRW) model in which an individual's trajectory through space is represented by a sequence of distinct, independent randomly oriented ‘moves’. It has long been recognized that the transformation of an animal's continuous movement path into a broken line is necessarily arbitrary and that probability distributions of move lengths and turning angles are model artefacts. Continuous-time analogues of CRWs that overcome this inherent shortcoming have appeared in the literature and are gaining prominence. In these models, velocities evolve as a Markovian process and have exponential autocorrelation. Integration of the velocity process gives the position process. Here, through a simple scaling argument and through an exact analytical analysis, it is shown that autocorrelation inevitably leads to Lévy walk (LW) movement patterns on timescales less than the autocorrelation timescale. This is significant because over recent years there has been an accumulation of evidence from a variety of experimental and theoretical studies that many organisms have movement patterns that can be approximated by LWs, and there is now intense debate about the relative merits of CRWs and LWs as representations of non-orientated animal movement patterns.


Oryx ◽  
2021 ◽  
pp. 1-9
Author(s):  
Helen M. K. O'Neill ◽  
Sarah M. Durant ◽  
Stefanie Strebel ◽  
Rosie Woodroffe

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.


2008 ◽  
Vol 10 ◽  
pp. 47-60 ◽  
Author(s):  
ELC Shepard ◽  
RP Wilson ◽  
F Quintana ◽  
A Gómez Laich ◽  
N Liebsch ◽  
...  

2012 ◽  
Vol 82 (1) ◽  
pp. 96-106 ◽  
Author(s):  
Tal Avgar ◽  
Anna Mosser ◽  
Glen S. Brown ◽  
John M. Fryxell

Sensors ◽  
2019 ◽  
Vol 19 (20) ◽  
pp. 4411 ◽  
Author(s):  
Jehyeok Rew ◽  
Sungwoo Park ◽  
Yongjang Cho ◽  
Seungwon Jung ◽  
Eenjun Hwang

Observing animal movements enables us to understand animal behavior changes, such as migration, interaction, foraging, and nesting. Based on spatiotemporal changes in weather and season, animals instinctively change their position for foraging, nesting, or breeding. It is known that moving patterns are closely related to their traits. Analyzing and predicting animals’ movement patterns according to spatiotemporal change offers an opportunity to understand their unique traits and acquire ecological insights into animals. Hence, in this paper, we propose an animal movement prediction scheme using a predictive recurrent neural network architecture. To do that, we first collect and investigate geo records of animals and conduct pattern refinement by using random forest interpolation. Then, we generate animal movement patterns using the kernel density estimation and build a predictive recurrent neural network model to consider the spatiotemporal changes. In the experiment, we perform various predictions using 14 K long-billed curlew locations that contain their five-year movements of the breeding, non-breeding, pre-breeding, and post-breeding seasons. The experimental results confirm that our predictive model based on recurrent neural networks can be effectively used to predict animal movement.


2017 ◽  
Vol 98 (5) ◽  
pp. 1463-1478 ◽  
Author(s):  
Dana L Karelus ◽  
J Walter McCown ◽  
Brian K Scheick ◽  
Madelon van de Kerk ◽  
Benjamin M Bolker ◽  
...  

Abstract A greater understanding of how environmental factors and anthropogenic landscape features influence animal movements can inform management and potentially aid in mitigating human–wildlife conflicts. We investigated the movement patterns of 16 Florida black bears (Ursus americanus floridanus; 6 females, 10 males) in north-central Florida at multiple temporal scales using GPS data collected from 2011 to 2014. We calculated bi-hourly step-lengths and directional persistence, as well as daily and weekly observed displacements and expected displacements. We used those movement metrics as response variables in linear mixed models and tested for effects of sex, season, and landscape features. We found that step-lengths of males were generally longer than step-lengths of females, and both sexes had the shortest step-lengths during the daytime. Bears moved more slowly (shorter step-lengths) and exhibited less directed movement when near creeks, in forested wetlands, and in marsh habitats, possibly indicating foraging behavior. In urban areas, bears moved more quickly (longer step-lengths) and along more directed paths. The results were similar across all temporal scales. Major roads tended to act as a semipermeable barrier to bear movement. Males crossed major roads more frequently than females but both sexes crossed major roads much less frequently than minor roads. Our findings regarding the influence of landscape and habitat features on movement patterns of Florida black bears could be useful for planning effective wildlife corridors and understanding how future residential or commercial development and road expansions may affect animal movement.


2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 297-297
Author(s):  
Andres Cibils ◽  
Rick Estell ◽  
Alfredo Gonzalez ◽  
Sheri Spiegal ◽  
Martha Anderson ◽  
...  

Abstract Body temperature and movement patterns of Angus Hereford crossbred (AH) vs. Raramuri Criollo (RC) nursing cows were monitored in summer 2016 and 2017. AH and RC cows grazed separately in two adjacent Chihuahuan Desert pastures (1190ha, 1165ha) in a crossover design for 4 weeks each year. Body temperature (BodyT) was monitored at 10 min intervals by placing blank CIDRs containing a temperature logger in 10 cows per breed. Seven to 9 AH and RC cows were also fitted with GPS collars that recorded position and ambient temperature (CollarT) at 10 min intervals. A landscape thermal map (LandT) was developed for habitat analysis. Data were analyzed within four daytime segments: dawn (sunrise to 9AM); pre-noon (9AM to noon); post-noon (noon to 3PM); and dusk (3PM to sunset). ANOVA was used to determine whether BodyT, animal movement, CollarT, and mean LandT position within each day segment were different for AH vs. RC cows. Breed nested within Year*Pasture was treated as the experimental unit. BodyT increased as a day progressed and was higher (P < 0.05) in AH vs. RC during post-noon (38.83 vs. 38.42oC) and dusk (39.22 vs. 38.70oC). Compared to AH counterparts, RC cows traveled farther (4.7 vs. 2.7 km*daytime h-1, P < 0.05), at higher velocities (5.9 vs. 3.5 m*min-1, P < 0.05) and spent more time grazing (5.6 vs. 4.3 daytime h; P < 0.05) and traveling (0.7 vs. 0.3 daytime h; P < 0.05) during all four daytime segments. Largest breed differences were observed during the hottest segments of the day (post-noon and dusk). Increasing CollarT throughout a day was associated with selection of cooler landscape locations (LandT) in both breeds. Apparent lower body heat load in RC cows may reduce constraints on their movement patterns compared to AH cows grazing Chihuahuan Desert rangeland in summer.


ARCTIC ◽  
2018 ◽  
Vol 71 (2) ◽  
Author(s):  
Crystal L. Glassburn ◽  
Ben A. Potter ◽  
Jamie L. Clark ◽  
Joshua D. Reuther ◽  
Darren L. Bruning ◽  
...  

Studies addressing prehistoric mobility in animals typically use isotopic analyses of sequentially formed tissues, such as the growth layers in teeth, to infer physical movement on the landscape. Strontium isotope ratios (87Sr/86Sr values), which vary geographically, are particularly useful for this purpose, especially when paired with stable oxygen isotope ratios (δ18O), which vary seasonally. Together, these two isotope systems can provide information about past animal movement patterns on a seasonal scale. However, while many studies have used 87Sr/86Sr and δ18O values from analyses of sequentially formed tissues for this purpose, there have been limited analyses on modern animals of known movement patterns across high-latitude regions. In this pilot study, we sequentially sampled and analyzed one second molar (M2) and two third molars (M3) from two bison (Bison bison bison) from the Delta bison herd, which resides in interior Alaska and has known and documented seasonal mobility patterns. The resulting 87Sr/86Sr values from the teeth were compared to a high-resolution 87Sr/86Sr isoscape for the region and were paired with δ18O analyses to determine whether the seasonal 87Sr/86Sr values matched the predicted values for each of the seasonal bison habitat areas. The results indicate that the 87Sr/86Sr and δ18O values reliably reflected the known seasonal mobility patterns of bison and suggest that this approach could be used to investigate the mobility patterns of prehistoric bison in Alaska and surrounding high-latitude regions.


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