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Evans TS, Ellison N, Boudreau MR, Strickland BK, Street GM, Iglay RB. What drives wild pig (Sus scrofa) movement in bottomland and upland forests? MOVEMENT ECOLOGY 2024; 12:32. [PMID: 38664784 PMCID: PMC11044336 DOI: 10.1186/s40462-024-00472-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 04/08/2024] [Indexed: 04/28/2024]
Abstract
BACKGROUND The wild pig (Sus scrofa) is an exotic species that has been present in the southeastern United States for centuries yet continues to expand into new areas dominated by bottomland and upland forests, the latter of which are less commonly associated with wild pigs. Here, we aimed to investigate wild pig movement and space use attributes typically used to guide wild pig management among multiple spatiotemporal scales. Our investigation focused on a newly invaded landscape dominated by bottomland and upland forests. METHODS We examined (1) core and total space use using an autocorrelated kernel density estimator; (2) resource selection patterns and hot spots of space use in relation to various landscape features using step-selection analysis; and (3) daily and hourly differences in movement patterns between non-hunting and hunting seasons using generalized additive mixed models. RESULTS Estimates of total space use among wild pigs (n = 9) were smaller at calculated core (1.2 ± 0.3 km2) and 90% (5.2 ± 1.5 km2) isopleths than estimates reported in other landscapes in the southeastern United States, suggesting that wild pigs were able to meet foraging, cover, and thermoregulatory needs within smaller areas. Generally, wild pigs selected areas closer to herbaceous, woody wetlands, fields, and perennial streams, creating corridors of use along these features. However, selection strength varied among individuals, reinforcing the generalist, adaptive nature of wild pigs. Wild pigs also showed a tendency to increase movement from fall to winter, possibly paralleling increases in hard mast availability. During this time, there were also increases in anthropogenic pressures (e.g. hunting), causing movements to become less diurnal as pressure increased. CONCLUSIONS Our work demonstrates that movement patterns by exotic generalists must be understood across individuals, the breadth of landscapes they can invade, and multiple spatiotemporal scales. This improved understanding will better inform management strategies focused on curbing emerging invasions in novel landscapes, while also protecting native natural resources.
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Affiliation(s)
- Tyler S Evans
- Department of Wildlife, Fisheries and Aquaculture, Mississippi State University, 775 Stone Boulevard, Mississippi State, Mississippi, 39762, USA.
| | - Natasha Ellison
- Department of Wildlife, Fisheries and Aquaculture, Mississippi State University, 775 Stone Boulevard, Mississippi State, Mississippi, 39762, USA
| | - Melanie R Boudreau
- Department of Wildlife, Fisheries and Aquaculture, Mississippi State University, 775 Stone Boulevard, Mississippi State, Mississippi, 39762, USA
| | - Bronson K Strickland
- Department of Wildlife, Fisheries and Aquaculture, Mississippi State University, 775 Stone Boulevard, Mississippi State, Mississippi, 39762, USA
| | - Garrett M Street
- Department of Wildlife, Fisheries and Aquaculture, Mississippi State University, 775 Stone Boulevard, Mississippi State, Mississippi, 39762, USA
| | - Raymond B Iglay
- Department of Wildlife, Fisheries and Aquaculture, Mississippi State University, 775 Stone Boulevard, Mississippi State, Mississippi, 39762, USA
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Stalter L, Terry M, Riley A, Leeds A. Home is where the home range is: Identifying territoriality and exhibit preferences in an ex-situ group of all-male Nile crocodiles (Crocodylus niloticus). PLoS One 2024; 19:e0297687. [PMID: 38271386 PMCID: PMC10810454 DOI: 10.1371/journal.pone.0297687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Accepted: 01/10/2024] [Indexed: 01/27/2024] Open
Abstract
Here, the presence or absence of territoriality was evaluated in an all-male Nile crocodile (Crocodylus niloticus) group living in an ex-situ environment. Location data for each crocodile within the exhibit were collected three times per day over a two-year period, including two warm seasons and two cold seasons. A geographic information system (GIS) was used to create seasonal home ranges and core areas for each crocodile, to quantify the overlap of these home ranges and core areas to assess potential territoriality, and to calculate exhibit preferences of the group. Core area overlap was significantly lower than home range overlap, suggesting the crocodiles established territories within their exhibit. This pattern of behavior was similar across seasons, though it moderately intensified during the cold season. The crocodiles appeared to be more territorial in water, as overlap was most concentrated on the central beach, the only feature utilized more than expected based in its availability in the exhibit. These findings highlight the behavioral complexity of Nile crocodiles in human care, specifically the ability of Nile crocodiles to adapt to ex-situ environments similar to their wild counterparts by forming territories despite spatial constraints. Identifying the presence of territorial behavior is important for the care and welfare of ex-situ animals, as territorial animals have specific requirements that may result in increased agonism when unmet. It can also provide valuable context to aid in mitigation strategies, for example, when undesirable levels of agonism do occur. The findings here provide an example of how methodology from the wildlife ecology field can be adapted to ex-situ settings using a GIS and contributes to the current understanding of crocodilian behavior in human care.
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Affiliation(s)
- Laura Stalter
- Animals, Science and Environment, Disney’s Animal Kingdom, Lake Buena Vista, FL, United States of America
| | - Megan Terry
- Animals, Science and Environment, Disney’s Animal Kingdom, Lake Buena Vista, FL, United States of America
| | - Alex Riley
- Animals, Science and Environment, Disney’s Animal Kingdom, Lake Buena Vista, FL, United States of America
| | - Austin Leeds
- Animals, Science and Environment, Disney’s Animal Kingdom, Lake Buena Vista, FL, United States of America
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Yang A, Boughton R, Miller RS, Snow NP, Vercauteren KC, Pepin KM, Wittemyer G. Individual-level patterns of resource selection do not predict hotspots of contact. MOVEMENT ECOLOGY 2023; 11:74. [PMID: 38037089 PMCID: PMC10687890 DOI: 10.1186/s40462-023-00435-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 11/08/2023] [Indexed: 12/02/2023]
Abstract
Contact among animals is crucial for various ecological processes, including social behaviors, disease transmission, and predator-prey interactions. However, the distribution of contact events across time and space is heterogeneous, influenced by environmental factors and biological purposes. Previous studies have assumed that areas with abundant resources and preferred habitats attract more individuals and, therefore, lead to more contact. To examine the accuracy of this assumption, we used a use-available framework to compare landscape factors influencing the location of contacts between wild pigs (Sus scrofa) in two study areas in Florida and Texas (USA) from those influencing non-contact space use. We employed a contact-resource selection function (RSF) model, where contact locations were defined as used points and locations without contact as available points. By comparing outputs from this contact RSF with a general, population-level RSF, we assessed the factors driving both habitat selection and contact. We found that the landscape predictors (e.g., wetland, linear features, and food resources) played different roles in habitat selection from contact processes for wild pigs in both study areas. This indicated that pigs interacted with their landscapes differently when choosing habitats compared to when they encountered other individuals. Consequently, relying solely on the spatial overlap of individual or population-level RSF models may lead to a misleading understanding of contact-related ecology. Our findings challenge prevailing assumptions about contact and introduce innovative approaches to better understand the ecological drivers of spatially explicit contact. By accurately predicting the spatial distribution of contact events, we can enhance our understanding of contact based ecological processes and their spatial dynamics.
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Affiliation(s)
- Anni Yang
- Department of Geography and Environmental Sustainability, University of Oklahoma, Norman, OK, 73019, USA.
| | - Raoul Boughton
- Archbold Biological Station, Buck Island Ranch, Lake Placid, FL, 33852, USA
| | - Ryan S Miller
- United States Department of Agriculture, Animal and Plant Health Inspection Service, Veterinary Service, Center for Epidemiology and Animal Health, 2150 Centre Avenue, Fort Collins, CO, 80526, USA
| | - Nathan P Snow
- United States Department of Agriculture, Animal and Plant Health Inspection Service, National Wildlife Research Center, Wildlife Services, Fort Collins, CO, 80521, USA
| | - Kurt C Vercauteren
- United States Department of Agriculture, Animal and Plant Health Inspection Service, National Wildlife Research Center, Wildlife Services, Fort Collins, CO, 80521, USA
| | - Kim M Pepin
- United States Department of Agriculture, Animal and Plant Health Inspection Service, National Wildlife Research Center, Wildlife Services, Fort Collins, CO, 80521, USA
| | - George Wittemyer
- Department of Fish, Wildlife and Conservation Biology, Colorado State University, Fort Collins, CO, 80523, USA
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Clontz LM, Yang A, Chinn SM, Pepin KM, VerCauteren KC, Wittemyer G, Miller RS, Beasley JC. Role of social structure in establishment of an invasive large mammal after translocation. PEST MANAGEMENT SCIENCE 2023; 79:3819-3829. [PMID: 37218996 DOI: 10.1002/ps.7567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 05/18/2023] [Accepted: 05/23/2023] [Indexed: 05/24/2023]
Abstract
BACKGROUND Data on the movement behavior of translocated wild pigs is needed to develop appropriate response strategies for containing and eliminating new source populations following translocation events. We conducted experimental trials to compare the home range establishment and space-use metrics, including the number of days and distance traveled before becoming range residents, for wild pigs translocated with their social group and individually. RESULTS We found wild pigs translocated with their social group made less extensive movements away from the release location and established a stable home range ~5 days faster than those translocated individually. We also examined how habitat quality impacted the home range sizes of translocated wild pigs and found wild pigs maintained larger ranges in areas with higher proportion of low-quality habitat. CONCLUSION Collectively, our findings suggest translocations of invasive wild pigs have a greater probability of establishing a viable population near the release site when habitat quality is high and when released with members of their social unit compared to individuals moved independent of their social group or to low-quality habitat. However, all wild pigs translocated in our study made extensive movements from their release location, highlighting the potential for single translocation events of either individuals or groups to have far-reaching consequences within a much broader landscape beyond the location where they are released. These results highlight the challenges associated with containing populations in areas where illegal introduction of wild pigs occurs, and the need for rapid response once releases are identified. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Affiliation(s)
- Lindsay M Clontz
- Savannah River Ecology Laboratory, Warnell School of Forestry and Natural Resources, University of Georgia, Aiken, South Carolina, USA
| | - Anni Yang
- United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, Fort Collins, Colorado, USA
- Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, Colorado, USA
- Department of Geography and Environmental Sustainability, University of Oklahoma, Norman, Oklahoma, USA
| | - Sarah M Chinn
- Savannah River Ecology Laboratory, Warnell School of Forestry and Natural Resources, University of Georgia, Aiken, South Carolina, USA
| | - Kim M Pepin
- United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, Fort Collins, Colorado, USA
| | - Kurt C VerCauteren
- United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, Fort Collins, Colorado, USA
| | - George Wittemyer
- Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Ryan S Miller
- United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, Fort Collins, Colorado, USA
| | - James C Beasley
- Savannah River Ecology Laboratory, Warnell School of Forestry and Natural Resources, University of Georgia, Aiken, South Carolina, USA
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Kilgo JC, Vukovich M, Cox KJ, Larsen M, Mims TT, Garabedian JE. Assessing whole-sounder removal versus traditional control for reducing invasive wild pig (Sus scrofa) populations. PEST MANAGEMENT SCIENCE 2023; 79:3033-3042. [PMID: 36966457 DOI: 10.1002/ps.7478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 03/20/2023] [Accepted: 03/26/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND Trapping is commonly used as the primary management tool in attempts to reduce invasive wild pigs (Sus scrofa), but traditional trapping techniques are often ineffective. However, recently developed traps permit the capture of entire social groups (sounders) of wild pigs, and the strategy of whole-sounder removal may achieve more effective control. Our objective was to experimentally compare traditional control (TC; primarily traditional trapping, but including hunting with dogs, and opportunistic shooting) and whole-sounder removal (WSR) strategies by assessing density reduction and removal rate after 1 and 2 years of treatment. RESULTS After 1 year of trapping, average wild pig density on WSR units declined 53% and remained stable after the second year, whereas on TC units, pig density did not differ after trapping, although it declined 33% and remained stable after the second year of trapping. The median removal rate (percentage of uniquely marked pigs present at the beginning of each year that were removed) was 42.5% for WSR units and 0.0% for TC units during 2018 and were 29.6% from WSR units and 5.3% from TC units during 2019. CONCLUSIONS WSR removal was more effective at reducing wild pig density than TC, but factors such as previous exposure of this population to traditional traps and the lack of barriers to recolonization from surrounding areas may have reduced WSR efficacy. WSR can effectively reduce wild pig density to a greater extent than TC, but managers should recognize the additional time and expense necessary for implementation. Published 2023. This article is a U.S. Government work and is in the public domain in the USA. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Affiliation(s)
- John C Kilgo
- USDA Forest Service, Southern Research Station, New Ellenton, SC, USA
| | - Mark Vukovich
- USDA Forest Service, Southern Research Station, New Ellenton, SC, USA
| | - Kyle J Cox
- USDA Forest Service, Southern Research Station, New Ellenton, SC, USA
| | - Michael Larsen
- USDA Forest Service, Savannah River, New Ellenton, SC, USA
| | - Thomas T Mims
- USDA Forest Service, Savannah River, New Ellenton, SC, USA
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Garabedian JE, Cox KJ, Vukovich M, Kilgo JC. Co‐occurrence of native white‐tailed deer and invasive wild pigs: Evidence for competition? Ecosphere 2023. [DOI: 10.1002/ecs2.4435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023] Open
Affiliation(s)
- James E. Garabedian
- USDA Forest Service, Southern Research Station New Ellenton South Carolina USA
| | - Kyle J. Cox
- USDA Forest Service, Southern Research Station New Ellenton South Carolina USA
| | - Mark Vukovich
- USDA Forest Service, Southern Research Station New Ellenton South Carolina USA
| | - John C. Kilgo
- USDA Forest Service, Southern Research Station New Ellenton South Carolina USA
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Snow NP, Glow MP, Lavelle MJ, Fischer JW, Cook SM, Lutman M, Foster JA, VerCauteren KC. Dry and Unwary are Best Conditions for Baiting Wild Pigs (Sus scrofa). Appl Anim Behav Sci 2022. [DOI: 10.1016/j.applanim.2022.105777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Schlichting PE, Boughton RK, Anderson W, Wight B, VerCauteren KC, Miller RS, Lewis JS. Seasonal variation in space use and territoriality in a large mammal (Sus scrofa). Sci Rep 2022; 12:4023. [PMID: 35256629 PMCID: PMC8901613 DOI: 10.1038/s41598-022-07297-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 01/25/2022] [Indexed: 11/12/2022] Open
Abstract
An individual’s spatial behavior is shaped by social and environmental factors and provides critical information about population processes to inform conservation and management actions. Heterogeneity in spatial overlap among conspecifics can be evaluated using estimates of home ranges and core areas and used to understand factors influencing space use and territoriality. To understand and test predictions about spatial behavior in an invasive large mammal, the wild pig (Sus scrofa), we examined variation in space use between sexes and seasons. We predicted that if animals were territorial that there would be a reduction in space-use overlap when comparing overlap of home ranges (HR–HR), to home ranges and core areas (HR–CA), and in-turn between core areas (CA–CA). Home ranges and core areas were estimated for 54 wild pigs at Buck Island Ranch, FL from GPS telemetry data. Overlap indices were calculated to estimate the strength (space-use overlap) and number of potential interactions within three wet seasons (June–October) and two dry seasons (December–April). Among sexes, home range size did not vary seasonally, and males exhibited larger home ranges compared to females (M = 10.36 ± 0.79 km2 (± SE), F = 3.21 ± 0.16 km2). Strength of overlap varied by season with wild pig home ranges overlapping more during the dry season. Males interacted with a greater number of individuals of both sexes, compared to females, and exhibited greater strength of overlap during the dry season. Consistent with our predictions, wild pigs appeared to exhibit territorial behavior, where strength of overlap decreased when comparing HR–HR to HR–CA and HR–CA to CA–CA. Our framework can be used to understand patterns of space use and territoriality in populations, which has important implications in understanding intraspecific interactions and population processes, such as how pathogens and parasites might spread within and among populations.
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