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James L, Reynolds AM, Mellor IR, Davies TGE. A Sublethal Concentration of Sulfoxaflor Has Minimal Impact on Buff-Tailed Bumblebee ( Bombus terrestris) Locomotor Behaviour under Aversive Conditioning. TOXICS 2023; 11:279. [PMID: 36977044 PMCID: PMC10057571 DOI: 10.3390/toxics11030279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 03/10/2023] [Accepted: 03/16/2023] [Indexed: 06/18/2023]
Abstract
Pesticide exposure has been cited as a key threat to insect pollinators. Notably, a diverse range of potential sublethal effects have been reported in bee species, with a particular focus on effects due to exposure to neonicotinoid insecticides. Here, a purpose-built thermal-visual arena was used in a series of pilot experiments to assess the potential impact of approximate sublethal concentrations of the next generation sulfoximine insecticide sulfoxaflor (5 and 50 ppb) and the neonicotinoid insecticides thiacloprid (500 ppb) and thiamethoxam (10 ppb), on the walking trajectory, navigation and learning abilities of the buff-tailed bumblebee (Bombus terrestris audax) when subjected to an aversive conditioning task. The results suggest that only thiamethoxam prevents forager bees from improving in key training parameters (speed and distanced travelled) within the thermal visual arena. Power law analyses further revealed that a speed-curvature power law, previously reported as being present in the walking trajectories of bumblebees, is potentially disrupted under thiamethoxam (10 ppb) exposure, but not under sulfoxaflor or thiacloprid exposure. The pilot assay described provides a novel tool with which to identify subtle sublethal pesticide impacts, and their potential causes, on forager bees, that current ecotoxicological tests are not designed to assess.
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Affiliation(s)
- Laura James
- Protecting Crops and the Environment, Rothamsted Research, West Common, Harpenden AL5 2JQ, UK (A.M.R.)
- Faculty of Medicine & Health Sciences, School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK;
| | - Andrew M. Reynolds
- Protecting Crops and the Environment, Rothamsted Research, West Common, Harpenden AL5 2JQ, UK (A.M.R.)
| | - Ian R. Mellor
- Faculty of Medicine & Health Sciences, School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK;
| | - T. G. Emyr Davies
- Protecting Crops and the Environment, Rothamsted Research, West Common, Harpenden AL5 2JQ, UK (A.M.R.)
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2
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Potts JR, Börger L. How to scale up from animal movement decisions to spatiotemporal patterns: An approach via step selection. J Anim Ecol 2023; 92:16-29. [PMID: 36321473 PMCID: PMC10099581 DOI: 10.1111/1365-2656.13832] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 10/16/2022] [Indexed: 11/17/2022]
Abstract
Uncovering the mechanisms behind animal space use patterns is of vital importance for predictive ecology, thus conservation and management of ecosystems. Movement is a core driver of those patterns so understanding how movement mechanisms give rise to space use patterns has become an increasingly active area of research. This study focuses on a particular strand of research in this area, based around step selection analysis (SSA). SSA is a popular way of inferring drivers of movement decisions, but, perhaps less well appreciated, it also parametrises a model of animal movement. Of key interest is that this model can be propagated forwards in time to predict the space use patterns over broader spatial and temporal scales than those that pertain to the proximate movement decisions of animals. Here, we provide a guide for understanding and using the various existing techniques for scaling up step selection models to predict broad-scale space use patterns. We give practical guidance on when to use which technique, as well as specific examples together with code in R and Python. By pulling together various disparate techniques into one place, and providing code and instructions in simple examples, we hope to highlight the importance of these techniques and make them accessible to a wider range of ecologists, ultimately helping expand the usefulness of SSA.
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Affiliation(s)
- Jonathan R Potts
- School of Mathematics and Statistics, University of Sheffield, Sheffield, UK
| | - Luca Börger
- Department of Biosciences, College of Science, Swansea University, Swansea, UK.,Centre for Biomathematics, College of Science, Swansea University, Swansea, UK
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3
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Theng M, Milleret C, Bracis C, Cassey P, Delean S. Confronting spatial capture-recapture models with realistic animal movement simulations. Ecology 2022; 103:e3676. [PMID: 35253209 DOI: 10.1002/ecy.3676] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 08/26/2021] [Accepted: 09/14/2021] [Indexed: 12/13/2022]
Abstract
Spatial capture-recapture (SCR) models have emerged as a robust method to estimate the population density of mobile animals. However, model evaluation has generally been based on data simulated from simplified representations of animal space use. Here, we generated data from animal movement simulated from a mechanistic individual-based model, in which movement emerges from the individual's response to a changing environment (i.e., from the bottom-up), driven by key ecological processes (e.g., resource memory and territoriality). We drew individual detection data from simulated movement trajectories and fitted detection data sets to a basic, resource selection and transience SCR model, as well as their variants accounting for resource-driven heterogeneity in density and detectability. Across all SCR models, abundance estimates were robust to multiple, but low-degree violations of the specified movement processes (e.g., resource selection). SCR models also successfully captured the positive effect of resource quality on density. However, covariate models failed to capture the finer scale effect of resource quality on detectability and space use, which may be a consequence of the low temporal resolution of SCR data sets and/or model misspecification. We show that home-range size is challenging to infer from the scale parameter alone, compounded by reliance on conventional measures of "true" home-range size that are highly sensitive to sampling regime. Additionally, we found the transience model challenging to fit, probably due to data sparsity and violation of the assumption of normally distributed inter-occasion movement of activity centers, suggesting that further development of the model is required for general applicability. Our results showed that further integration of complex movement into SCR models may not be necessary for population estimates of abundance when the level of individual heterogeneity induced by the underlying movement process is low, but appears warranted in terms of accurately revealing finer scale patterns of ecological and movement processes. Further investigation into whether this holds true in populations with other types of realistic movement characteristics is merited. Our study provides a framework to generate realistic SCR data sets to develop and evaluate more complex movement processes in SCR models.
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Affiliation(s)
- Meryl Theng
- School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Cyril Milleret
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Norway
| | - Chloe Bracis
- TIMC / MAGE, Université Grenoble Alpes, Grenoble, France
| | - Phillip Cassey
- School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Steven Delean
- School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
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4
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Kilgo JC, Garabedian JE, Vukovich M, Schlichting PE, Byrne ME, Beasley JC. Food resources affect territoriality of invasive wild pig sounders with implications for control. Sci Rep 2021; 11:18821. [PMID: 34552124 PMCID: PMC8458451 DOI: 10.1038/s41598-021-97798-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 08/30/2021] [Indexed: 11/13/2022] Open
Abstract
Interest in control methods for invasive wild pigs (Sus scrofa) has increased due to their range expansion, population growth, and an improved understanding of their destructive ecological and economic effects. Recent technological advances in traps for control of pig populations facilitate capture of entire social groups (sounders), but the efficacy of “whole-sounder” trapping strategies is heavily dependent on the degree of territoriality among sounders, a topic little research has explored. We assessed territoriality in wild pig sounders on the Savannah River Site, South Carolina, USA, and examined whether availability of food resources provided by a municipal-waste landfill affected among-sounder territoriality. We estimated utilization distribution overlap and dynamic interactions among 18 neighboring sounders around a landfill. We found that although neighboring sounders overlapped in space, intensity of use in shared areas was uniformly low, indicating territorial behavior. Neighbors tended to share slightly more space when closer to the landfill waste cells, indicating availability of a super-abundant resource somewhat weakens the degree of territoriality among sounders. Nevertheless, we conclude that sounders behaved in a generally territorial manner, and we discuss implications for whole-sounder trapping programs, particularly near concentrated resources such as landfills and crop fields.
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Affiliation(s)
- John C Kilgo
- USDA Forest Service, Southern Research Station, P.O. Box 700, New Ellenton, SC, 29809, USA.
| | - James E Garabedian
- USDA Forest Service, Southern Research Station, P.O. Box 700, New Ellenton, SC, 29809, USA
| | - Mark Vukovich
- USDA Forest Service, Southern Research Station, P.O. Box 700, New Ellenton, SC, 29809, USA.,USDA Forest Service, Shawnee National Forest, 602 North First St., Vienna, IL, 62995, USA
| | - Peter E Schlichting
- Savannah River Ecology Laboratory, Warnell School of Forestry and Natural Resources, University of Georgia, P.O. Drawer E, Aiken, SC, 29802, USA.,Illinois Department of Natural Resources, 1 Natural Resources Way, Springfield, IL, 62702, USA
| | - Michael E Byrne
- Savannah River Ecology Laboratory, Warnell School of Forestry and Natural Resources, University of Georgia, P.O. Drawer E, Aiken, SC, 29802, USA.,School of Natural Resources, University of Missouri, Columbia, MO, 65211, USA
| | - James C Beasley
- Savannah River Ecology Laboratory, Warnell School of Forestry and Natural Resources, University of Georgia, P.O. Drawer E, Aiken, SC, 29802, USA
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5
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Cardells J, Lizana V, Martí-Marco A, Lavín S, Velarde R, Rossi L, Moroni B. First description of sarcoptic mange in an Iberian hare (Lepus granatensis). CURRENT RESEARCH IN PARASITOLOGY & VECTOR-BORNE DISEASES 2021; 1:100021. [PMID: 35284901 PMCID: PMC8906140 DOI: 10.1016/j.crpvbd.2021.100021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/10/2021] [Accepted: 03/11/2021] [Indexed: 11/24/2022]
Abstract
The Iberian hare (Lepus granatensis) is a popular small game species in the Iberian Peninsula, and it has never been reported to be affected by sarcoptic mange. An adult female Iberian hare with overt skin lesions on forelimbs and ventral thorax, suggestive of sarcoptic mange, was culled in Quart de les Valls municipality in the Valencian Community, Spain, in 2019. Skin scrapings were digested in 10% KOH solutions to confirm the presence of mites. Ten Sarcoptes microsatellite markers were used to characterize the genetic structure of mites obtained from the hare, and from sympatric and allopatric wild rabbits (Oryctolagus cuniculus) and red foxes (Vulpes vulpes). A total of 56 alleles were counted across the 10 microsatellite loci. Six private alleles were found at four loci (Sarms 33, 38, 41, 45). The multivariate analysis characterized three main clusters, corresponding to mites collected on foxes originating from Catalonia, foxes from Valencia and the hare plus wild rabbits. To our knowledge, this is the first reported case of sarcoptic mange in the Iberian hare. The origin was molecularly traced back to contacts with endemically infected wild rabbits. We encourage further investigations on cross-transmissibility of S. scabiei between wild rabbits and the diverse representatives of Lepus spp. Crusted scabies in an Iberian hare was detected for the first time in Valencia, Spain in 2019. Wild rabbits might be a natural source of infection of S. scabiei for the Iberian hare, rather than sympatric predators. Microsatellite markers are efficient epidemiological tools for tracing the source of Sarcoptes scabiei infection.
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Affiliation(s)
- Jesús Cardells
- Servicio de Análisis, Investigación, Gestión de Animales Silvestres (SAIGAS), Facultad de Veterinaria, Universidad Cardenal Herrera-CEU, CEU Universities Alfara del Patriarca, Valencia, Spain
- Wildlife Ecology & Health Group (WE&H), Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona, Spain
| | - Victor Lizana
- Servicio de Análisis, Investigación, Gestión de Animales Silvestres (SAIGAS), Facultad de Veterinaria, Universidad Cardenal Herrera-CEU, CEU Universities Alfara del Patriarca, Valencia, Spain
- Wildlife Ecology & Health Group (WE&H), Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona, Spain
| | - Alba Martí-Marco
- Servicio de Análisis, Investigación, Gestión de Animales Silvestres (SAIGAS), Facultad de Veterinaria, Universidad Cardenal Herrera-CEU, CEU Universities Alfara del Patriarca, Valencia, Spain
| | - Santiago Lavín
- Wildlife Ecology & Health Group (WE&H), Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona, Spain
| | - Roser Velarde
- Wildlife Ecology & Health Group (WE&H), Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona, Spain
| | - Luca Rossi
- Dipartimento di Scienze Veterinarie, Università degli Studi di Torino, Largo Paolo Braccini 2, 10095, Grugliasco, Italy
| | - Barbara Moroni
- Dipartimento di Scienze Veterinarie, Università degli Studi di Torino, Largo Paolo Braccini 2, 10095, Grugliasco, Italy
- Corresponding author.
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6
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Ellison N, Hatchwell BJ, Biddiscombe SJ, Napper CJ, Potts JR. Mechanistic home range analysis reveals drivers of space use patterns for a non-territorial passerine. J Anim Ecol 2020; 89:2763-2776. [PMID: 32779181 DOI: 10.1111/1365-2656.13292] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 06/04/2020] [Indexed: 01/26/2023]
Abstract
Home ranging is a near-ubiquitous phenomenon in the animal kingdom. Understanding the behavioural mechanisms that give rise to observed home range patterns is thus an important general question, and mechanistic home range analysis (MHRA) provides the tools to address it. However, such analysis has hitherto been principally restricted to scent-marking territorial animals, so its potential breadth of application has not been tested. Here, we apply MHRA to a population of long-tailed tits Aegithalos caudatus, a non-territorial passerine, in the non-breeding season where there is no clear 'central place' near which birds need to remain. The aim is to uncover the principal movement mechanisms underlying observed home range formation. Our foundational models consist of memory-mediated conspecific avoidance between flocks, combined with attraction to woodland. These are then modified to incorporate the effects of flock size and relatedness (i.e. kinship), to uncover the effect of these on the mechanisms of home range formation. We found that a simple model of spatial avoidance, together with attraction to the central parts of woodland areas, accurately captures long-tailed tit home range patterns. Refining these models further, we show that the magnitude of spatial avoidance by a flock is negatively correlated to both the relative size of the flock (compared to its neighbour) and the relatedness of the flock with its neighbour. Our study applies MHRA beyond the confines of scent-marking, territorial animals, so paves the way for much broader taxonomic application. These could potentially help uncover general properties underlying the emergence of animal space use patterns. This is also the first study to apply MHRA to questions of relatedness and flock size, thus broadening the potential possible applications of this suite of analytic techniques.
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Affiliation(s)
- Natasha Ellison
- School of Mathematics and Statistics, University of Sheffield, Sheffield, UK
| | - Ben J Hatchwell
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Sarah J Biddiscombe
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Clare J Napper
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Jonathan R Potts
- School of Mathematics and Statistics, University of Sheffield, Sheffield, UK
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7
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Tolhurst BA, Baker RJ, Cagnacci F, Scott DM. Spatial Aspects of Gardens Drive Ranging in Urban Foxes ( Vulpes vulpes): The Resource Dispersion Hypothesis Revisited. Animals (Basel) 2020; 10:ani10071167. [PMID: 32660022 PMCID: PMC7401560 DOI: 10.3390/ani10071167] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 07/06/2020] [Accepted: 07/07/2020] [Indexed: 11/16/2022] Open
Abstract
Red foxes are a well-established species of urban ecosystems in the UK and worldwide. Understanding the spatial ecology of foxes in urban landscapes is important for enhancement of urban biodiversity and effective disease management. The Resource Dispersion Hypothesis (RDH) holds that territory (home range) size is linked to distribution and richness of habitat patches such that aggregation of rich resources should be negatively associated with range size. Here, we tested the RDH on a sample of 20 red foxes (Vulpes vulpes) in the city of Brighton and Hove. We focused on residential garden areas, as foxes were associated with these in previous studies. We equipped 12 male and 8 female foxes with GPS collars recording at 15 min intervals during discrete seasons over four years. We regressed fox core area size against garden size, number of garden patches, and edge density within and between patches as extracted from GIS in a series of bivariate linear mixed models. We found that foxes used smaller core areas where gardens were large and well-connected and larger core areas where numerous, smaller gardens were fragmented by internal barriers (e.g., fences, walls) or bisected by other habitats such as managed grassland or built-up areas. Our findings confirm the RDH and help to inform future urban planning for wildlife.
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Affiliation(s)
- Bryony A. Tolhurst
- Ecology, Conservation and Zoonosis (ECZ) Research and Enterprise Group, Huxley Building, University of Brighton, Brighton BN2 4GJ, UK;
- Correspondence:
| | - Rowenna J. Baker
- Ecology, Conservation and Zoonosis (ECZ) Research and Enterprise Group, Huxley Building, University of Brighton, Brighton BN2 4GJ, UK;
| | - Francesca Cagnacci
- Research and Innovation Centre, Fondazione Edmund Mach, Via Mach 1, San Michele all’Adige, 38010 Trentino, Italy;
| | - Dawn M. Scott
- School of Life Sciences, Huxley Building, Keele University, Keele ST5 5BG, UK;
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8
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Extra Territorial Excursions by European badgers are not limited by age, sex or season. Sci Rep 2020; 10:9665. [PMID: 32541685 PMCID: PMC7296015 DOI: 10.1038/s41598-020-66809-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 05/27/2020] [Indexed: 11/09/2022] Open
Abstract
European badgers (Meles meles) in medium and high density populations show strong territorial behaviour. Territories in these populations are contiguous, well-marked and often unchanging over many years. However, badgers do not always stay within their territorial boundaries. In our medium-density population, most individual badgers made extra-territorial excursions (ETEs) throughout the year. ETEs were most frequent between April and September and least frequent in December and January (the period of winter lethargy). Male badgers made longer and more frequent ETEs than females (especially between January and March, and in autumn). Breeding females made longer and more frequent ETEs than non-breeding females in November. While these peaks correspond with the main mating seasons, mating activity does not explain ETEs throughout the year. The shorter, but more frequent, ETEs in summer months may serve a monitoring purpose, rather than simply providing additional mating opportunities with badgers from outside the 'home' social group. We found that young badgers did not make regular ETEs until the summer of their second year. If badgers could be vaccinated as cubs, this would reduce any potential risk of TB spread during ETEs.
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9
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McClure KM, Gilbert AT, Chipman RB, Rees EE, Pepin KM. Variation in host home range size decreases rabies vaccination effectiveness by increasing the spatial spread of rabies virus. J Anim Ecol 2020; 89:1375-1386. [PMID: 31957005 PMCID: PMC7317853 DOI: 10.1111/1365-2656.13176] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 11/21/2019] [Indexed: 12/13/2022]
Abstract
Animal movement influences the spatial spread of directly transmitted wildlife disease through host-host contact structure. Wildlife disease hosts vary in home range-associated foraging and social behaviours, which may increase the spread and intensity of disease outbreaks. The consequences of variation in host home range movement and space use on wildlife disease dynamics are poorly understood, but could help to predict disease spread and determine more effective disease management strategies. We developed a spatially explicit individual-based model to examine the effect of spatiotemporal variation in host home range size on the spatial spread rate, persistence and incidence of rabies virus (RABV) in raccoons (Procyon lotor). We tested the hypothesis that variation in home range size increases RABV spread and decreases vaccination effectiveness in host populations following pathogen invasion into a vaccination zone. We simulated raccoon demography and RABV dynamics across a range of magnitudes and variances in weekly home range size for raccoons. We examined how variable home range size influenced the relative effectiveness of three components of oral rabies vaccination (ORV) programmes targeting raccoons-timing and frequency of bait delivery, width of the ORV zone and proportion of hosts immunized. Variability in weekly home range size increased RABV spread rates by 1.2-fold to 5.2-fold compared to simulations that assumed a fixed home range size. More variable host home range sizes decreased relative vaccination effectiveness by 71% compared to less variable host home range sizes under conventional vaccination conditions. We found that vaccination timing was more influential for vaccination effectiveness than vaccination frequency or vaccination zone width. Our results suggest that variation in wildlife home range movement behaviour increases the spatial spread and incidence of RABV. Our vaccination results underscore the importance of prioritizing individual-level space use and movement data collection to understand wildlife disease dynamics and plan their effective control and elimination.
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Affiliation(s)
- Katherine M. McClure
- United States Department of Agriculture, Animal and Plant Health Inspection ServiceNational Wildlife Research CenterFort CollinsCOUSA
- Department of Microbiology, Immunology, and PathologyColorado State UniversityFort CollinsCOUSA
- Present address:
Cornell Atkinson Center for Sustainability and the Cornell Wildlife Health CenterCornell UniversityIthacaNYUSA
| | - Amy T. Gilbert
- United States Department of Agriculture, Animal and Plant Health Inspection ServiceNational Wildlife Research CenterFort CollinsCOUSA
| | - Richard B. Chipman
- United States Department of Agriculture, Animal and Plant Health Inspection ServiceNational Rabies Management ProgramConcordNHUSA
| | - Erin E. Rees
- Land and Sea Systems Analysis Inc.GranbyQCCanada
- National Microbiology LaboratoryPublic Health Risk Sciences DivisionPublic Health Agency of CanadaSaint‐HyacintheQCCanada
| | - Kim M. Pepin
- United States Department of Agriculture, Animal and Plant Health Inspection ServiceNational Wildlife Research CenterFort CollinsCOUSA
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10
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Kranstauber B, Gall GEC, Vink T, Clutton-Brock T, Manser MB. Long-term movements and home-range changes: Rapid territory shifts in meerkats. J Anim Ecol 2019; 89:772-783. [PMID: 31691963 DOI: 10.1111/1365-2656.13129] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 08/23/2019] [Indexed: 11/29/2022]
Abstract
Territoriality and stable home ranges are a common space-use pattern among animals. These ranges provide its inhabitants with important resources and thus favourable territories are associated with an increased fitness. While the role of territory quality and changes of territory ownership have often been investigated, the changes of territorial boundaries have been less studied. Here, we investigated space-use changes in a social mammal species, applying a novel analytical approach, calculating long-term dissimilarity in space use using distancematrices based on periodic utilization distributions. This approach makes it possible to identify different space-use patterns, which cannot be distinguished by only considering changes between consecutive time periods. We analysed meerkat (Suricata suricatta) movements of a total of 24 different groups over a 16-year period, resulting in 134 group years. We then correlated the identified home-range changes to life-history events and possible environmental drivers. Groups had stable territories for several years before they abandoned their home range mostly to move quickly to new areas where they again remained for several years. Of 26 identified sudden shifts, 22 occurred in the summer months and often involved distances larger than the original home-range size. Home-range movements that were close together in time were often also spatially clustered and moved in a similar direction. These shifts were often preceded by more frequent interactions between groups, but did not seem to be a product of direct displacements by other groups. The normalized difference vegetation index as a measure of food production and social factors such as dominance changes did not correlate to changes. Against our expectation space-use changes were not accumulations of small changes, but more often involved long-distance moves into unknown ranges. This means that the groups enter areas where they cannot profit from local knowledge. The methods used identify episodes of long stability alternated by sudden changes in meerkats and in general provides insight into long-term space use. Our methods can be used to analyse long-term space use, either within or across species.
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Affiliation(s)
- Bart Kranstauber
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.,Kalahari Meerkat Project, Kuruman River Reserve, Northern Cape, South Africa
| | - Gabriella E C Gall
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.,Kalahari Meerkat Project, Kuruman River Reserve, Northern Cape, South Africa
| | - Tim Vink
- Kalahari Meerkat Project, Kuruman River Reserve, Northern Cape, South Africa
| | - Tim Clutton-Brock
- Kalahari Meerkat Project, Kuruman River Reserve, Northern Cape, South Africa.,Department of Zoology, University of Cambridge, Cambridge, UK.,Mammal Research Institute, University of Pretoria, Pretoria, South Africa
| | - Marta B Manser
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.,Kalahari Meerkat Project, Kuruman River Reserve, Northern Cape, South Africa.,Mammal Research Institute, University of Pretoria, Pretoria, South Africa
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11
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Dorning J, Harris S. Understanding the intricacy of canid social systems: Structure and temporal stability of red fox (Vulpes vulpes) groups. PLoS One 2019; 14:e0220792. [PMID: 31509536 PMCID: PMC6738593 DOI: 10.1371/journal.pone.0220792] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 07/23/2019] [Indexed: 11/18/2022] Open
Abstract
Red foxes have a highly flexible social system. Despite numerous studies worldwide, our understanding of the pattern and stability of fox social relationships remains limited. We applied social network analysis to camera trap data collected at high-quality foraging patches to examine the social structure of a population of urban red foxes. Foxes encountered a conspecific on 13% of patch visits, and had significant preferred and avoided companionships in all seasons. They also associated in communities that matched territorial space use, confirming that territories can be analysed separately to increase power without excluding too many social partners. Foxes maintained stable, long-term relationships with other territory residents, but the average longevity of relationships varied seasonally, suggesting that social connectivity, particularly between foxes from different social groups, is influenced by their annual life cycle. The probability of re-association after a given time lag was highest in spring and summer, during cub birth and rearing, and lowest in the winter mating season, when mean relationship duration was shorter. 33% of fox relationships lasted for four consecutive seasons and were probably between territory residents. 14% lasted for around 20 days and were probably between residents and visitors from adjacent territories. The majority (53%) lasted less than one day, particularly during dispersal and mating, and were probably between foxes from non-adjacent social groups. Social structure varied between groups; in one group the death of the dominant male caused significant social disruption for two seasons. This is the first application of social network analysis to multiple red fox social groups. However, our analyses were based on interactions at high quality food patches; social connections may differ when foxes are resting, travelling and foraging elsewhere in their territory. Our results will inform management practices, particularly for disease spread and population control.
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Affiliation(s)
- Jo Dorning
- School of Biological Sciences, University of Bristol, Bristol, England, United Kingdom
- * E-mail:
| | - Stephen Harris
- School of Biological Sciences, University of Bristol, Bristol, England, United Kingdom
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12
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Dorning J, Harris S. The challenges of recognising individuals with few distinguishing features: Identifying red foxes Vulpes vulpes from camera-trap photos. PLoS One 2019; 14:e0216531. [PMID: 31071143 PMCID: PMC6508734 DOI: 10.1371/journal.pone.0216531] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 04/18/2019] [Indexed: 12/23/2022] Open
Abstract
Over the last two decades, camera traps have revolutionised the ability of biologists to undertake faunal surveys and estimate population densities, although identifying individuals of species with subtle markings remains challenging. We conducted a two-year camera-trapping study as part of a long-term study of urban foxes: our objectives were to determine whether red foxes could be identified individually from camera-trap photos, and highlight camera-trapping protocols and techniques to facilitate photo identification of species with few or subtle natural markings. We collected circa 800,000 camera-trap photos over 4945 camera days in suburban gardens in the city of Bristol, UK: 152,134 (19%) included foxes, of which 13,888 (9%) contained more than one fox. These provided 174,063 timestamped capture records of individual foxes; 170,923 were of foxes ≥ 3 months old. Younger foxes were excluded because they have few distinguishing features. We identified the individual (192 different foxes: 110 males, 49 females, 33 of unknown sex) in 168,417 (99%) of these capture records; the remainder could not be identified due to poor image quality or because key identifying feature(s) were not visible. We show that carefully designed survey techniques facilitate individual identification of subtly-marked species. Accuracy is enhanced by camera-trapping techniques that yield large numbers of high resolution, colour images from multiple angles taken under varying environmental conditions. While identifying foxes manually was labour-intensive, currently available automated identification systems are unlikely to achieve the same levels of accuracy, especially since different features were used to identify each fox, the features were often inconspicuous, and their appearance varied with environmental conditions. We discuss how studies based on low numbers of photos, or which fail to identify the individual in a significant proportion of photos, risk losing important biological information, and may come to erroneous conclusions.
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Affiliation(s)
- Jo Dorning
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
- * E-mail:
| | - Stephen Harris
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
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13
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Dorning J, Harris S. Quantifying group size in the red fox: impacts of definition, season and intrusion by non‐residents. J Zool (1987) 2019. [DOI: 10.1111/jzo.12650] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- J. Dorning
- School of Biological Sciences University of Bristol Bristol UK
| | - S. Harris
- School of Biological Sciences University of Bristol Bristol UK
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14
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Getz WM, Marshall CR, Carlson CJ, Giuggioli L, Ryan SJ, Romañach SS, Boettiger C, Chamberlain SD, Larsen L, D'Odorico P, O'Sullivan D. Making ecological models adequate. Ecol Lett 2017; 21:153-166. [PMID: 29280332 DOI: 10.1111/ele.12893] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 11/07/2017] [Accepted: 11/12/2017] [Indexed: 12/22/2022]
Abstract
Critical evaluation of the adequacy of ecological models is urgently needed to enhance their utility in developing theory and enabling environmental managers and policymakers to make informed decisions. Poorly supported management can have detrimental, costly or irreversible impacts on the environment and society. Here, we examine common issues in ecological modelling and suggest criteria for improving modelling frameworks. An appropriate level of process description is crucial to constructing the best possible model, given the available data and understanding of ecological structures. Model details unsupported by data typically lead to over parameterisation and poor model performance. Conversely, a lack of mechanistic details may limit a model's ability to predict ecological systems' responses to management. Ecological studies that employ models should follow a set of model adequacy assessment protocols that include: asking a series of critical questions regarding state and control variable selection, the determinacy of data, and the sensitivity and validity of analyses. We also need to improve model elaboration, refinement and coarse graining procedures to better understand the relevancy and adequacy of our models and the role they play in advancing theory, improving hind and forecasting, and enabling problem solving and management.
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Affiliation(s)
- Wayne M Getz
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, 94720, USA.,Schools of Mathematical Sciences and Life Sciences, University of KwaZulu, Natal, South Africa
| | - Charles R Marshall
- Museum of Paleontology and Department Integrative Biology, University of California, Berkeley, CA, 94720, USA
| | - Colin J Carlson
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, 94720, USA
| | - Luca Giuggioli
- Bristol Centre for Complexity Sciences, Department of Engineering Mathematics, and School of Biological Sciences, University of Bristol, Bristol, UK
| | - Sadie J Ryan
- Department of Geography, and Emerging Pathogens Institute, University of Florida, Gainesville, FL, 32601, USA.,Schools of Mathematical Sciences and Life Sciences, University of KwaZulu, Natal, South Africa
| | - Stephanie S Romañach
- Wetland and Aquatic Research Center, U.S. Geological Survey, Fort Lauderdale, FL, 33314, USA
| | - Carl Boettiger
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, 94720, USA
| | - Samuel D Chamberlain
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, 94720, USA
| | - Laurel Larsen
- Department of Geography, University of California, Berkeley, CA, 94720, USA
| | - Paolo D'Odorico
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, 94720, USA
| | - David O'Sullivan
- Department of Geography, University of California, Berkeley, CA, 94720, USA
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15
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Potts JR, Lewis MA. How memory of direct animal interactions can lead to territorial pattern formation. J R Soc Interface 2017; 13:rsif.2016.0059. [PMID: 27146687 DOI: 10.1098/rsif.2016.0059] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 04/07/2016] [Indexed: 11/12/2022] Open
Abstract
Mechanistic home range analysis (MHRA) is a highly effective tool for understanding spacing patterns of animal populations. It has hitherto focused on populations where animals defend their territories by communicating indirectly, e.g. via scent marks. However, many animal populations defend their territories using direct interactions, such as ritualized aggression. To enable application of MHRA to such populations, we construct a model of direct territorial interactions, using linear stability analysis and energy methods to understand when territorial patterns may form. We show that spatial memory of past interactions is vital for pattern formation, as is memory of 'safe' places, where the animal has visited but not suffered recent territorial encounters. Additionally, the spatial range over which animals make decisions to move is key to understanding the size and shape of their resulting territories. Analysis using energy methods, on a simplified version of our system, shows that stability in the nonlinear system corresponds well to predictions of linear analysis. We also uncover a hysteresis in the process of territory formation, so that formation may depend crucially on initial space-use. Our analysis, in one dimension and two dimensions, provides mathematical groundwork required for extending MHRA to situations where territories are defended by direct encounters.
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Affiliation(s)
- Jonathan R Potts
- School of Mathematics and Statistics, University of Sheffield, Sheffield, UK
| | - Mark A Lewis
- Centre for Mathematical Biology, Department of Mathematical and Statistical Sciences, University of Alberta, 632 CAB, Edmonton, Alberta, Canada T6G 2G1 Department of Biological Sciences, University of Alberta, Edmonton, Canada
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16
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Süld K, Tammeleht E, Valdmann H, Saarma U. Severe impact of sarcoptic mange on the movements and space use for one of its most important vector species, the raccoon dog. Vet Parasitol 2017; 243:67-70. [PMID: 28807313 DOI: 10.1016/j.vetpar.2017.05.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 05/29/2017] [Accepted: 05/30/2017] [Indexed: 11/19/2022]
Abstract
Sarcoptic mange is a highly contagious zoonotic skin disease that can have severe effect on population dynamics of many wild mammals. However, very little is known about its effect on the activity and space use of infected animals. In this study we equipped two raccoon dogs (Nyctereutes procyonoides) in a mange outbreak area with radio-collars and observed the spatial and temporal effects of sarcoptic mange to these individuals. Initially, the raccoon dogs had no external symptoms of mange infection, but developed these during the study period. One of the raccoon dogs died just 32 and the other 52days after collaring. During a relatively short period before their death, there was an abrupt and drastic decline in their home range size. For one of the animals it started about 1 month before its death and the home range size reduced >1000×, whereas for the other raccoon dog it took place within the last week, decreasing >200×. The daily covered distances also declined considerably. These results indicate that at the later stage sarcoptic mange affected the physiological state of the diseased animals so forcefully that made them almost immobile. Our results show for the first time how rapid and severe could the impact of sarcoptic mange be for one of its most important reservoir and vector species.
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Affiliation(s)
- Karmen Süld
- Department of Zoology, Institute of Ecology and Earth Sciences, University of Tartu, Vanemuise 46, 51014 Tartu, Estonia, Estonia
| | - Egle Tammeleht
- Department of Zoology, Institute of Ecology and Earth Sciences, University of Tartu, Vanemuise 46, 51014 Tartu, Estonia, Estonia
| | - Harri Valdmann
- Department of Zoology, Institute of Ecology and Earth Sciences, University of Tartu, Vanemuise 46, 51014 Tartu, Estonia, Estonia
| | - Urmas Saarma
- Department of Zoology, Institute of Ecology and Earth Sciences, University of Tartu, Vanemuise 46, 51014 Tartu, Estonia, Estonia.
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17
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Potts JR, Petrovskii SV. Fortune favours the brave: Movement responses shape demographic dynamics in strongly competing populations. J Theor Biol 2017; 420:190-199. [DOI: 10.1016/j.jtbi.2017.03.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 02/20/2017] [Accepted: 03/10/2017] [Indexed: 11/25/2022]
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18
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Carricondo-Sanchez D, Odden M, Linnell JDC, Odden J. The range of the mange: Spatiotemporal patterns of sarcoptic mange in red foxes (Vulpes vulpes) as revealed by camera trapping. PLoS One 2017; 12:e0176200. [PMID: 28423011 PMCID: PMC5397041 DOI: 10.1371/journal.pone.0176200] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 04/06/2017] [Indexed: 11/30/2022] Open
Abstract
Sarcoptic mange is a widely distributed disease that affects numerous mammalian species. We used camera traps to investigate the apparent prevalence and spatiotemporal dynamics of sarcoptic mange in a red fox population in southeastern Norway. We monitored red foxes for five years using 305 camera traps distributed across an 18000 km2 area. A total of 6581 fox events were examined to visually identify mange compatible lesions. We investigated factors associated with the occurrence of mange by using logistic models within a Bayesian framework, whereas the spatiotemporal dynamics of the disease were analysed with space-time scan statistics. The apparent prevalence of the disease fluctuated over the study period with a mean of 3.15% and credible interval [1.25, 6.37], and our best logistic model explaining the presence of red foxes with mange-compatible lesions included time since the beginning of the study and the interaction between distance to settlement and season as explanatory variables. The scan analyses detected several potential clusters of the disease that varied in persistence and size, and the locations in the cluster with the highest probability were closer to human settlements than the other survey locations. Our results indicate that red foxes in an advanced stage of the disease are most likely found closer to human settlements during periods of low wild prey availability (winter). We discuss different potential causes. Furthermore, the disease appears to follow a pattern of small localized outbreaks rather than sporadic isolated events.
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Affiliation(s)
- David Carricondo-Sanchez
- Faculty of Applied Ecology and Agricultural Sciences, Hedmark University of Applied Sciences, Koppang, Norway
- * E-mail:
| | - Morten Odden
- Faculty of Applied Ecology and Agricultural Sciences, Hedmark University of Applied Sciences, Koppang, Norway
| | | | - John Odden
- Norwegian Institute for Nature Research, Trondheim, Norway
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19
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Moriarty KM, Linnell MA, Chasco BE, Epps CW, Zielinski WJ. Using high-resolution short-term location data to describe territoriality in Pacific martens. J Mammal 2017. [DOI: 10.1093/jmammal/gyx014] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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20
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Cholaquidis A, Fraiman R, Lugosi G, Pateiro-López B. Set estimation from reflected Brownian motion. J R Stat Soc Series B Stat Methodol 2016. [DOI: 10.1111/rssb.12149] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | - Gábor Lugosi
- Institució Catalana de Recerca i Estudis Avançats and Universitat Pompeu Fabra; Barcelona Spain
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21
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Tao Y, Börger L, Hastings A. Dynamic Range Size Analysis of Territorial Animals: An Optimality Approach. Am Nat 2016; 188:460-74. [PMID: 27622879 DOI: 10.1086/688257] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Home range sizes of territorial animals are often observed to vary periodically in response to seasonal changes in foraging opportunities. Here we develop the first mechanistic model focused on the temporal dynamics of home range expansion and contraction in territorial animals. We demonstrate how simple movement principles can lead to a rich suite of range size dynamics, by balancing foraging activity with defensive requirements and incorporating optimal behavioral rules into mechanistic home range analysis. Our heuristic model predicts three general temporal patterns that have been observed in empirical studies across multiple taxa. First, a positive correlation between age and territory quality promotes shrinking home ranges over an individual's lifetime, with maximal range size variability shortly before the adult stage. Second, poor sensory information, low population density, and large resource heterogeneity may all independently facilitate range size instability. Finally, aggregation behavior toward forage-rich areas helps produce divergent home range responses between individuals from different age classes. This model has broad applications for addressing important unknowns in animal space use, with potential applications also in conservation and health management strategies.
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22
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Perrucci S, Verin R, Mancianti F, Poli A. Sarcoptic mange and other ectoparasitic infections in a red fox ( Vulpes vulpes) population from central Italy. Parasite Epidemiol Control 2016; 1:66-71. [PMID: 29988193 PMCID: PMC5991845 DOI: 10.1016/j.parepi.2016.03.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Revised: 03/21/2016] [Accepted: 03/21/2016] [Indexed: 11/06/2022] Open
Abstract
Fifty red foxes (Vulpes vulpes) from the district of Pisa (central Italy) were examined for ectoparasites. Sarcoptic mange was diagnosed on the presence of clearly visible skin lesions with confirmatory demonstration of Sarcoptes scabiei at parasitological and histopathological analysis. Ticks and fleas were collected directly from the carcases during post mortem examination, fixed and identified by morphological examination. For the detection of ear Malassezia and mite infections, cytological and parasitological examinations of ear wax samples were performed. All data were statistically analysed using a χ2 test with the Yates correction. An overall prevalence of 84% for ectoparasitic infections was found in examined subjects. In regard to isolated ectoparasites, 38%, 8%, 82%, 6% and 8% of foxes resulted positive for S. scabiei, Otodectes cynotis, Malassezia spp., fleas (Archaeopsylla erinacei, Pulex irritans, Ctenocephalides canis) and ticks (Ixodes ricinus and Rhipicephalus sanguineus), respectively. Malassezia ear infection was significantly more prevalent in animals older than 1 year (P < 0.01). Prevalence (38%), severity of lesions and poor body conditions observed in most Sarcoptes-infected animals indicate that sarcoptic mange should be considered the most important ectoparasitic infection of red foxes in the examined area. An overall prevalence of 84% for ectoparasitic infections was found in 50 Italian red foxes. Red foxes were infected by ticks, mites, fleas and Malassezia yeasts. Auricular infection with Malassezia was significantly more prevalent in animals older than 1 year. Malassezia was almost constantly associated with the presence of Sarcoptes mites and skin lesions. Based on prevalence, lesions and body condition, sarcoptic mange was the most relevant disease.
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Affiliation(s)
- S Perrucci
- Dipartimento di Scienze Veterinarie, University of Pisa, Viale delle Piagge 2, 56124 Pisa, Italy
| | - R Verin
- Dipartimento di Scienze Veterinarie, University of Pisa, Viale delle Piagge 2, 56124 Pisa, Italy.,Section of Veterinary Pathology, School of Veterinary Science, University of Liverpool, Leahurst Campus, Chester High Road, Neston CH64 7TE, UK
| | - F Mancianti
- Dipartimento di Scienze Veterinarie, University of Pisa, Viale delle Piagge 2, 56124 Pisa, Italy
| | - A Poli
- Dipartimento di Scienze Veterinarie, University of Pisa, Viale delle Piagge 2, 56124 Pisa, Italy
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23
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A framework for analyzing the robustness of movement models to variable step discretization. J Math Biol 2016; 73:815-45. [PMID: 26852021 DOI: 10.1007/s00285-016-0969-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 09/22/2015] [Indexed: 10/22/2022]
Abstract
When sampling animal movement paths, the frequency at which location measurements are attempted is a critical feature for data analysis. Important quantities derived from raw data, e.g. travel distance or sinuosity, can differ largely based on the temporal resolution of the data. Likewise, when movement models are fitted to data, parameter estimates have been demonstrated to vary with sampling rate. Thus, biological statements derived from such analyses can only be made with respect to the resolution of the underlying data, limiting extrapolation of results and comparison between studies. To address this problem, we investigate whether there are models that are robust against changes in temporal resolution. First, we propose a mathematically rigorous framework, in which we formally define robustness as a model property. We then use the framework for a thorough assessment of a range of basic random walk models, in which we also show how robustness relates to other probabilistic concepts. While we found robustness to be a strong condition met by few models only, we suggest a new method to extend models so as to make them robust. Our framework provides a new systematic, mathematically founded approach to the question if, and how, sampling rate of movement paths affects statistical inference.
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24
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Sit-and-wait versus active-search hunting: A behavioral ecological model of optimal search mode. J Theor Biol 2015; 387:76-87. [DOI: 10.1016/j.jtbi.2015.09.022] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 07/29/2015] [Accepted: 09/18/2015] [Indexed: 11/20/2022]
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25
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Lai S, Bêty J, Berteaux D. Spatio-temporal hotspots of satellite-tracked arctic foxes reveal a large detection range in a mammalian predator. MOVEMENT ECOLOGY 2015; 3:37. [PMID: 26568827 PMCID: PMC4644628 DOI: 10.1186/s40462-015-0065-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 10/13/2015] [Indexed: 05/04/2023]
Abstract
BACKGROUND The scale at which animals perceive their environment is a strong fitness determinant, yet few empirical estimates of animal detection ranges exist, especially in mammalian predators. Using daily Argos satellite tracking of 26 adult arctic foxes (Vulpes lagopus) during a single winter in the High Canadian Arctic, we investigated the detection range of arctic foxes by detecting hotspots of fox activity on the sea ice. RESULTS While maintaining territories in the tundra, these solitary foragers occasionally used the sea ice where they sometimes formed spatio-temporal hotspots, likely scavenging on marine mammal carcasses. We detected 35 movements by 13 individuals forming five hotspots. Foxes often traveled more than 10 km, and up to 40 km, to reach hotspots, which lasted one-two weeks and could gather up to 12 individuals. The likelihood of a fox joining a hotspot was neither influenced by its distance from the hotspot nor by the distance of its home range to the coast. CONCLUSIONS Observed traveling distances may indicate a high detection range in arctic foxes, and our results suggest their ability to detect food sources on the sea ice from their terrestrial home range. While revealing a wide knowledge gap regarding resource detection abilities in mammalian predators, our study provides estimates of detection range useful for interpreting and modeling animal movements. It also allows a better understanding of foraging behavior and navigation capacity in terrestrial predators.
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Affiliation(s)
- Sandra Lai
- Canada Research Chair on Northern Biodiversity, Centre for Northern Studies and Quebec Center for Biodiversity Science, Université du Québec à Rimouski, 300 Allée des Ursulines, Rimouski, QC G5L 3A1 Canada
| | - Joël Bêty
- Canada Research Chair on Northern Biodiversity, Centre for Northern Studies and Quebec Center for Biodiversity Science, Université du Québec à Rimouski, 300 Allée des Ursulines, Rimouski, QC G5L 3A1 Canada
| | - Dominique Berteaux
- Canada Research Chair on Northern Biodiversity, Centre for Northern Studies and Quebec Center for Biodiversity Science, Université du Québec à Rimouski, 300 Allée des Ursulines, Rimouski, QC G5L 3A1 Canada
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26
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Anthropogenically-Mediated Density Dependence in a Declining Farmland Bird. PLoS One 2015; 10:e0139492. [PMID: 26431173 PMCID: PMC4592266 DOI: 10.1371/journal.pone.0139492] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Accepted: 09/13/2015] [Indexed: 12/02/2022] Open
Abstract
Land management intrinsically influences the distribution of animals and can consequently alter the potential for density-dependent processes to act within populations. For declining species, high densities of breeding territories are typically considered to represent productive populations. However, as density-dependent effects of food limitation or predator pressure may occur (especially when species are dependent upon separate nesting and foraging habitats), high territory density may limit per-capita productivity. Here, we use a declining but widespread European farmland bird, the yellowhammer Emberiza citrinella L., as a model system to test whether higher territory densities result in lower fledging success, parental provisioning rates or nestling growth rates compared to lower densities. Organic landscapes held higher territory densities, but nests on organic farms fledged fewer nestlings, translating to a 5 times higher rate of population shrinkage on organic farms compared to conventional. In addition, when parental provisioning behaviour was not restricted by predation risk (i.e., at times of low corvid activity), nestling provisioning rates were higher at lower territory densities, resulting in a much greater increase in nestling mass in low density areas, suggesting that food limitation occurred at high densities. These findings in turn suggest an ecological trap, whereby preferred nesting habitat does not provide sufficient food for rearing nestlings at high population density, creating a population sink. Habitat management for farmland birds should focus not simply on creating a high nesting density, but also on ensuring heterogeneous habitats to provide food resources in close proximity to nesting birds, even if this occurs through potentially restricting overall nest density but increasing population-level breeding success.
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27
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Lutnesky MM, Brown TR. Simulation of movement that potentially maximizes assessment, presence, and defense in territorial animals with varying movement strategies. Ecol Modell 2015. [DOI: 10.1016/j.ecolmodel.2015.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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28
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Penteriani V, del Mar Delgado M, Campioni L. Quantifying space use of breeders and floaters of a long-lived species using individual movement data. Naturwissenschaften 2015; 102:21. [DOI: 10.1007/s00114-015-1271-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 01/29/2015] [Accepted: 03/18/2015] [Indexed: 11/28/2022]
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29
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Kittle AM, Anderson M, Avgar T, Baker JA, Brown GS, Hagens J, Iwachewski E, Moffatt S, Mosser A, Patterson BR, Reid DEB, Rodgers AR, Shuter J, Street GM, Thompson ID, Vander Vennen LM, Fryxell JM. Wolves adapt territory size, not pack size to local habitat quality. J Anim Ecol 2015; 84:1177-86. [PMID: 25757794 DOI: 10.1111/1365-2656.12366] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 02/25/2015] [Indexed: 11/26/2022]
Abstract
1. Although local variation in territorial predator density is often correlated with habitat quality, the causal mechanism underlying this frequently observed association is poorly understood and could stem from facultative adjustment in either group size or territory size. 2. To test between these alternative hypotheses, we used a novel statistical framework to construct a winter population-level utilization distribution for wolves (Canis lupus) in northern Ontario, which we then linked to a suite of environmental variables to determine factors influencing wolf space use. Next, we compared habitat quality metrics emerging from this analysis as well as an independent measure of prey abundance, with pack size and territory size to investigate which hypothesis was most supported by the data. 3. We show that wolf space use patterns were concentrated near deciduous, mixed deciduous/coniferous and disturbed forest stands favoured by moose (Alces alces), the predominant prey species in the diet of wolves in northern Ontario, and in proximity to linear corridors, including shorelines and road networks remaining from commercial forestry activities. 4. We then demonstrate that landscape metrics of wolf habitat quality - projected wolf use, probability of moose occupancy and proportion of preferred land cover classes - were inversely related to territory size but unrelated to pack size. 5. These results suggest that wolves in boreal ecosystems alter territory size, but not pack size, in response to local variation in habitat quality. This could be an adaptive strategy to balance trade-offs between territorial defence costs and energetic gains due to resource acquisition. That pack size was not responsive to habitat quality suggests that variation in group size is influenced by other factors such as intraspecific competition between wolf packs.
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Affiliation(s)
- Andrew M Kittle
- Department of Integrative Biology, University of Guelph, 50 Stone Road E., Guelph, Ontario, N1G 2W1, Canada
| | - Morgan Anderson
- Department of Integrative Biology, University of Guelph, 50 Stone Road E., Guelph, Ontario, N1G 2W1, Canada
| | - Tal Avgar
- Department of Integrative Biology, University of Guelph, 50 Stone Road E., Guelph, Ontario, N1G 2W1, Canada
| | - James A Baker
- Department of Integrative Biology, University of Guelph, 50 Stone Road E., Guelph, Ontario, N1G 2W1, Canada
| | - Glen S Brown
- Ontario Ministry of Natural Resources, 1235 Queen Street East, Sault Ste. Marie, Ontario, P6A 2E5, Canada
| | - Jevon Hagens
- Centre for Northern Forest Ecosystem Research, Ontario Ministry of Natural Resources, Thunder Bay, Ontario, P7B 5E1, Canada
| | - Ed Iwachewski
- Centre for Northern Forest Ecosystem Research, Ontario Ministry of Natural Resources, Thunder Bay, Ontario, P7B 5E1, Canada
| | - Scott Moffatt
- Department of Integrative Biology, University of Guelph, 50 Stone Road E., Guelph, Ontario, N1G 2W1, Canada
| | - Anna Mosser
- Department of Integrative Biology, University of Guelph, 50 Stone Road E., Guelph, Ontario, N1G 2W1, Canada
| | - Brent R Patterson
- Wildlife Research and Development Section, Ontario Ministry of Natural Resources, Trent University, DNA Building, 2140 East Bank Drive, Peterborough, Ontario, K9J 7B8, Canada
| | - Douglas E B Reid
- Centre for Northern Forest Ecosystem Research, Ontario Ministry of Natural Resources, Thunder Bay, Ontario, P7B 5E1, Canada
| | - Arthur R Rodgers
- Centre for Northern Forest Ecosystem Research, Ontario Ministry of Natural Resources, Thunder Bay, Ontario, P7B 5E1, Canada
| | - Jen Shuter
- Centre for Northern Forest Ecosystem Research, Ontario Ministry of Natural Resources, Thunder Bay, Ontario, P7B 5E1, Canada
| | - Garrett M Street
- Department of Integrative Biology, University of Guelph, 50 Stone Road E., Guelph, Ontario, N1G 2W1, Canada
| | - Ian D Thompson
- Canadian Forest Service, 1219 Queen Street East, Sault Ste. Marie, Ontario, P6A 2E5, Canada
| | - Lucas M Vander Vennen
- Department of Integrative Biology, University of Guelph, 50 Stone Road E., Guelph, Ontario, N1G 2W1, Canada
| | - John M Fryxell
- Department of Integrative Biology, University of Guelph, 50 Stone Road E., Guelph, Ontario, N1G 2W1, Canada
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Riotte-Lambert L, Benhamou S, Chamaillé-Jammes S. How Memory-Based Movement Leads to Nonterritorial Spatial Segregation. Am Nat 2015; 185:E103-16. [DOI: 10.1086/680009] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Breed GA, Severns PM, Edwards AM. Apparent power-law distributions in animal movements can arise from intraspecific interactions. J R Soc Interface 2015; 12:rsif.2014.0927. [PMID: 25519992 DOI: 10.1098/rsif.2014.0927] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Lévy flights have gained prominence for analysis of animal movement. In a Lévy flight, step-lengths are drawn from a heavy-tailed distribution such as a power law (PL), and a large number of empirical demonstrations have been published. Others, however, have suggested that animal movement is ill fit by PL distributions or contend a state-switching process better explains apparent Lévy flight movement patterns. We used a mix of direct behavioural observations and GPS tracking to understand step-length patterns in females of two related butterflies. We initially found movement in one species (Euphydryas editha taylori) was best fit by a bounded PL, evidence of a Lévy flight, while the other (Euphydryas phaeton) was best fit by an exponential distribution. Subsequent analyses introduced additional candidate models and used behavioural observations to sort steps based on intraspecific interactions (interactions were rare in E. phaeton but common in E. e. taylori). These analyses showed a mixed-exponential is favoured over the bounded PL for E. e. taylori and that when step-lengths were sorted into states based on the influence of harassing conspecific males, both states were best fit by simple exponential distributions. The direct behavioural observations allowed us to infer the underlying behavioural mechanism is a state-switching process driven by intraspecific interactions rather than a Lévy flight.
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Affiliation(s)
- Greg A Breed
- Department of Biological Sciences, University of Alberta, Edmonton, Canada AB T6G 2E9
| | - Paul M Severns
- Department of Botany and Plant Pathology, Oregon State University, 2082 Cordley Hall, Corvallis, OR, USA
| | - Andrew M Edwards
- Marine Ecosystems and Aquaculture Division, Pacific Biological Station, Fisheries and Oceans Canada, 3190 Hammond Bay Road, Nanaimo, British Columbia, Canada V9T 6N7
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Potts JR, Mokross K, Lewis MA. A unifying framework for quantifying the nature of animal interactions. J R Soc Interface 2014; 11:rsif.2014.0333. [PMID: 24829284 DOI: 10.1098/rsif.2014.0333] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Collective phenomena, whereby agent-agent interactions determine spatial patterns, are ubiquitous in the animal kingdom. On the other hand, movement and space use are also greatly influenced by the interactions between animals and their environment. Despite both types of interaction fundamentally influencing animal behaviour, there has hitherto been no unifying framework for the models proposed in both areas. Here, we construct a general method for inferring population-level spatial patterns from underlying individual movement and interaction processes, a key ingredient in building a statistical mechanics for ecological systems. We show that resource selection functions, as well as several examples of collective motion models, arise as special cases of our framework, thus bringing together resource selection analysis and collective animal behaviour into a single theory. In particular, we focus on combining the various mechanistic models of territorial interactions in the literature with step selection functions, by incorporating interactions into the step selection framework and demonstrating how to derive territorial patterns from the resulting models. We demonstrate the efficacy of our model by application to a population of insectivore birds in the Amazon rainforest.
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Affiliation(s)
- Jonathan R Potts
- Centre for Mathematical Biology, Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2G1
| | - Karl Mokross
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA INPA, Projeto Dinâmica Biológica de Fragmentos Florestais, Avenue André Araújo 2936, Petrópolis, Manaus 69083-000, Brazil
| | - Mark A Lewis
- Centre for Mathematical Biology, Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2G1 Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2G1
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Potts JR, Mokross K, Stouffer PC, Lewis MA. Step selection techniques uncover the environmental predictors of space use patterns in flocks of Amazonian birds. Ecol Evol 2014; 4:4578-88. [PMID: 25558353 PMCID: PMC4278811 DOI: 10.1002/ece3.1306] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 09/30/2014] [Indexed: 11/24/2022] Open
Abstract
Understanding the behavioral decisions behind animal movement and space use patterns is a key challenge for behavioral ecology. Tools to quantify these patterns from movement and animal-habitat interactions are vital for transforming ecology into a predictive science. This is particularly important in environments undergoing rapid anthropogenic changes, such as the Amazon rainforest, where animals face novel landscapes. Insectivorous bird flocks are key elements of avian biodiversity in the Amazonian ecosystem. Therefore, disentangling and quantifying the drivers behind their movement and space use patterns is of great importance for Amazonian conservation. We use a step selection function (SSF) approach to uncover environmental drivers behind movement choices. This is used to construct a mechanistic model, from which we derive predicted utilization distributions (home ranges) of flocks. We show that movement decisions are significantly influenced by canopy height and topography, but depletion and renewal of resources do not appear to affect movement significantly. We quantify the magnitude of these effects and demonstrate that they are helpful for understanding various heterogeneous aspects of space use. We compare our results to recent analytic derivations of space use, demonstrating that the analytic approximation is only accurate when assuming that there is no persistence in the animals' movement. Our model can be translated into other environments or hypothetical scenarios, such as those given by proposed future anthropogenic actions, to make predictions of spatial patterns in bird flocks. Furthermore, our approach is quite general, so could potentially be used to understand the drivers of movement and spatial patterns for a wide variety of animal communities.
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Affiliation(s)
- Jonathan R Potts
- Department of Mathematical and Statistical Sciences, Centre for Mathematical Biology, University of Alberta Edmonton, Alberta, Canada ; Department of Mathematics and Statistics, University of Sheffield Sheffield, UK
| | - Karl Mokross
- School of Renewable Natural Resources, Louisiana State University Agricultural Center Baton Rouge, Louisiana, 70803 ; Projeto Dinâmica Biólogica de Fragmentos Florestais, INPA Av. André Araújo 2936, Petropólis, Manaus, 69083-000, Brazil
| | - Philip C Stouffer
- School of Renewable Natural Resources, Louisiana State University Agricultural Center Baton Rouge, Louisiana, 70803 ; Projeto Dinâmica Biólogica de Fragmentos Florestais, INPA Av. André Araújo 2936, Petropólis, Manaus, 69083-000, Brazil
| | - Mark A Lewis
- Department of Mathematical and Statistical Sciences, Centre for Mathematical Biology, University of Alberta Edmonton, Alberta, Canada ; Department of Biological Sciences, University of Alberta Edmonton, Alberta, Canada
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Giuggioli L, Kenkre VM. Consequences of animal interactions on their dynamics: emergence of home ranges and territoriality. MOVEMENT ECOLOGY 2014; 2:20. [PMID: 25709829 PMCID: PMC4337768 DOI: 10.1186/s40462-014-0020-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 08/08/2014] [Indexed: 05/31/2023]
Abstract
Animal spacing has important implications for population abundance, species demography and the environment. Mechanisms underlying spatial segregation have their roots in the characteristics of the animals, their mutual interaction and their response, collective as well as individual, to environmental variables. This review describes how the combination of these factors shapes the patterns we observe and presents a practical, usable framework for the analysis of movement data in confined spaces. The basis of the framework is the theory of interacting random walks and the mathematical description of out-of-equilibrium systems. Although our focus is on modelling and interpreting animal home ranges and territories in vertebrates, we believe further studies on invertebrates may also help to answer questions and resolve unanswered puzzles that are still inaccessible to experimental investigation in vertebrate species.
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Affiliation(s)
- Luca Giuggioli
- />Bristol Centre for Complexity Sciences, Department of Engineering Mathematics and School of Biological Sciences, University of Bristol, Bristol, BS8 1UB UK
| | - V M Kenkre
- />Consortium of the Americas for Interdisciplinary Science and Department of Physics and Astronomy, University of New Mexico, Albuquerque, 87131 New Mexico USA
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Bateman AW, Lewis MA, Gall G, Manser MB, Clutton-Brock TH. Territoriality and home-range dynamics in meerkats,Suricata suricatta: a mechanistic modelling approach. J Anim Ecol 2014; 84:260-71. [DOI: 10.1111/1365-2656.12267] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 07/01/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Andrew W. Bateman
- Department of Zoology; University of Cambridge; Downing Street Cambridge CB2 3EJ UK
- Department of Mathematical and Statistical Sciences; Department of Biological Sciences; University of Alberta; Edmonton AB T6G 2G1 Canada
- Kalahari Meerkat Project; Kuruman River Reserve; Northern Cape South Africa
| | - Mark A. Lewis
- Department of Mathematical and Statistical Sciences; Department of Biological Sciences; University of Alberta; Edmonton AB T6G 2G1 Canada
| | - Gabriella Gall
- Kalahari Meerkat Project; Kuruman River Reserve; Northern Cape South Africa
- Institute of Evolutionary Biology and Environmental Studies; University of Zurich; Winterthurerstrasse 190 CH-8057 Zurich Switzerland
| | - Marta B. Manser
- Kalahari Meerkat Project; Kuruman River Reserve; Northern Cape South Africa
- Institute of Evolutionary Biology and Environmental Studies; University of Zurich; Winterthurerstrasse 190 CH-8057 Zurich Switzerland
| | - Tim H. Clutton-Brock
- Department of Zoology; University of Cambridge; Downing Street Cambridge CB2 3EJ UK
- Kalahari Meerkat Project; Kuruman River Reserve; Northern Cape South Africa
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36
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Potts JR, Lewis MA. How do animal territories form and change? Lessons from 20 years of mechanistic modelling. Proc Biol Sci 2014; 281:20140231. [PMID: 24741017 PMCID: PMC4043092 DOI: 10.1098/rspb.2014.0231] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Territory formation is ubiquitous throughout the animal kingdom. At the individual
level, various behaviours attempt to exclude conspecifics from regions of space. At
the population level, animals often segregate into distinct territorial areas.
Consequently, it should be possible to derive territorial patterns from the
underlying behavioural processes of animal movements and interactions. Such
derivations are an important element in the development of an ecological theory that
can predict the effects of changing conditions on territorial populations. Here, we
review the approaches developed over the past 20 years or so, which go under the
umbrella of ‘mechanistic territorial models’. We detail the two main
strands to this research: partial differential equations and individual-based
approaches, showing what each has offered to our understanding of territoriality and
how they can be unified. We explain how they are related to other approaches to
studying territories and home ranges, and point towards possible future
directions.
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Affiliation(s)
- Jonathan R Potts
- Department of Mathematical and Statistical Sciences, Centre for Mathematical Biology, University of Alberta, , Edmonton, , Alberta, Canada , T6G 2G1, Department of Biological Sciences, University of Alberta, , Edmonton, , Alberta, Canada , T6G 2G1
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Potts JR, Bastille-Rousseau G, Murray DL, Schaefer JA, Lewis MA. Predicting local and non-local effects of resources on animal space use using a mechanistic step selection model. Methods Ecol Evol 2014; 5:253-262. [PMID: 25834721 PMCID: PMC4375923 DOI: 10.1111/2041-210x.12150] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Accepted: 12/02/2013] [Indexed: 11/29/2022]
Abstract
Predicting space use patterns of animals from their interactions with the environment is fundamental for understanding the effect of habitat changes on ecosystem functioning. Recent attempts to address this problem have sought to unify resource selection analysis, where animal space use is derived from available habitat quality, and mechanistic movement models, where detailed movement processes of an animal are used to predict its emergent utilization distribution. Such models bias the animal's movement towards patches that are easily available and resource-rich, and the result is a predicted probability density at a given position being a function of the habitat quality at that position. However, in reality, the probability that an animal will use a patch of the terrain tends to be a function of the resource quality in both that patch and the surrounding habitat.We propose a mechanistic model where this non-local effect of resources naturally emerges from the local movement processes, by taking into account the relative utility of both the habitat where the animal currently resides and that of where it is moving. We give statistical techniques to parametrize the model from location data and demonstrate application of these techniques to GPS location data of caribou (Rangifer tarandus) in Newfoundland.Steady-state animal probability distributions arising from the model have complex patterns that cannot be expressed simply as a function of the local quality of the habitat. In particular, large areas of good habitat are used more intensively than smaller patches of equal quality habitat, whereas isolated patches are used less frequently. Both of these are real aspects of animal space use missing from previous mechanistic resource selection models.Whilst we focus on habitats in this study, our modelling framework can be readily used with any environmental covariates and therefore represents a unification of mechanistic modelling and step selection approaches to understanding animal space use.
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Affiliation(s)
- Jonathan R Potts
- Centre for Mathematical Biology, Department of Mathematical and Statistical Sciences, University of Alberta Edmonton, AB, T6G 1G1, Canada
| | | | - Dennis L Murray
- Environmental and Life Sciences Graduate Program, Trent University Peterborough, ON K9J 7B8, Canada
| | - James A Schaefer
- Environmental and Life Sciences Graduate Program, Trent University Peterborough, ON K9J 7B8, Canada
| | - Mark A Lewis
- Centre for Mathematical Biology, Department of Mathematical and Statistical Sciences, University of Alberta Edmonton, AB, T6G 1G1, Canada ; Department of Biological Sciences, University of Alberta Edmonton, AB T6G 2E9, Canada
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Abstract
Collective animal behavior studies have led the way in developing models that account for a large number of individuals, but mostly have considered situations in which alignment and attraction play a key role, such as in schooling and flocking. By quantifying how animals react to one another's presence, when interaction is via conspecific avoidance rather than alignment or attraction, we present a mechanistic insight that enables us to link individual behavior and space use patterns. As animals respond to both current and past positions of their neighbors, the assumption that the relative location of individuals is statistically and history independent is not tenable, underscoring the limitations of traditional space use studies. We move beyond that assumption by constructing a framework to analyze spatial segregation of mobile animals when neighbor proximity may elicit a retreat, and by linking conspecific encounter rate to history-dependent avoidance behavior. Our approach rests on the knowledge that animals communicate by modifying the environment in which they live, providing a method to analyze social cohesion as stigmergy, a form of mediated animal-animal interaction. By considering a population of animals that mark the terrain as they move, we predict how the spatiotemporal patterns that emerge depend on the degree of stigmergy of the interaction processes. We find in particular that nonlocal decision rules may generate a nonmonotonic dependence of the animal encounter rate as a function of the tendency to retreat from locations recently visited by other conspecifics, which has fundamental implications for epidemic disease spread and animal sociality.
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