1
|
Lombardi JV, Sergeyev M, Tewes ME, Schofield LR, Wilkins RN. Spatial capture-recapture and LiDAR-derived vegetation metrics reveal high densities of ocelots on Texas ranchlands. FRONTIERS IN CONSERVATION SCIENCE 2022. [DOI: 10.3389/fcosc.2022.1003044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Reliable estimates of population density and size are crucial to wildlife conservation, particularly in the context of the Endangered Species Act. In the United States, ocelots (Leopardus pardalis pardalis) were listed as endangered in 1982, and to date, only one population density estimate has been reported in Texas. In this study, we integrated vegetation metrics derived from LiDAR and spatial capture-recapture models to discern factors of ocelot encounter rates and estimated localized population estimates on private ranchlands in coastal southern Texas. From September 2020 to May 2021, we conducted a camera trap study across 42 camera stations on the East Foundation’s El Sauz Ranch, which was positioned within a larger region of highly suitable woody and herbaceous cover for ocelots. We observed a high density of ocelots (17.6 ocelots/100 km2) and a population size of 36.3 ocelots (95% CI: 26.1–58.6) with the 206.25 km2 state space area of habitat. The encounter probability of ocelots increased with greater canopy cover at 1-2 m height and decreasing proximity to woody cover. These results suggest that the incorporation of LiDAR-derived vegetative canopy metrics allowed us to understand where ocelots are likely to be detected, which may aid in current and future population monitoring efforts. These population estimates reflect the first spatially explicit and most recent estimates in a portion of the northernmost population of ocelots in southern Texas. This study further demonstrates the importance of private working lands for the recovery of ocelots in Texas.
Collapse
|
2
|
Chaudhuri S, Rajaraman R, Kalyanasundaram S, Sathyakumar S, Krishnamurthy R. N-mixture model-based estimate of relative abundance of sloth bear ( Melursus ursinus) in response to biotic and abiotic factors in a human-dominated landscape of central India. PeerJ 2022; 10:e13649. [PMID: 36523470 PMCID: PMC9745790 DOI: 10.7717/peerj.13649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 06/07/2022] [Indexed: 12/12/2022] Open
Abstract
Reliable estimation of abundance is a prerequisite for a species' conservation planning in human-dominated landscapes, especially if the species is elusive and involved in conflicts. As a means of population estimation, the importance of camera traps has been recognized globally, although estimating the abundance of unmarked, cryptic species has always been a challenge to conservation biologists. This study explores the use of the N-mixture model with three probability distributions, i.e., Poisson, negative binomial (NB) and zero-inflated Poisson (ZIP), to estimate the relative abundance of sloth bears (Melursus ursinus) based on a camera trapping exercise in Sanjay Tiger Reserve, Madhya Pradesh from December 2016 to April 2017. We used environmental and anthropogenic covariates to model the variation in the abundance of sloth bears. We also compared null model estimates (mean site abundance) obtained from the N-mixture model to those of the Royle-Nichols abundance-induced heterogeneity model (RN model) to assess the application of similar site-structured models. Models with Poisson distributions produced ecologically realistic and more precise estimates of mean site abundance (λ = 2.60 ± 0.64) compared with other distributions, despite the relatively high Akaike Information Criterion value. Area of mixed and sal forest, the photographic capture rate of humans and distance to the nearest village predicted a higher relative abundance of sloth bears. Mean site abundance estimates of sloth bears obtained from the N-mixture model (Poisson distribution) and the RN model were comparable, indicating the overall utility of these models in this field. However, density estimates of sloth bears based on spatially explicit methods are essential for evaluating the efficacy of the relatively more cost-effective N-mixture model. Compared to commonly used index/encounter-based methods, the N-mixture model equipped with knowledge on governing biotic and abiotic factors provides better relative abundance estimates for a species like the sloth bear. In the absence of absolute abundance estimates, the present study could be insightful for the long-term conservation and management of sloth bears.
Collapse
Affiliation(s)
- Sankarshan Chaudhuri
- Department of Landscape Level Planning and Management, Wildlife Institute of India, Dehradun, Uttarakhand, India
| | - Rajasekar Rajaraman
- Department of Landscape Level Planning and Management, Wildlife Institute of India, Dehradun, Uttarakhand, India
| | | | - Sambandam Sathyakumar
- Department of Endangered Species Management, Wildlife Institute of India, Dehradun, Uttarakhand, India
| | - Ramesh Krishnamurthy
- Department of Landscape Level Planning and Management, Wildlife Institute of India, Dehradun, Uttarakhand, India,Faculty of Forestry, University of British Columbia, Vancouver, British Columbia, Canada
| |
Collapse
|
3
|
Chandler RB, Crawford DA, Garrison EP, Miller KV, Cherry MJ. Modeling abundance, distribution, movement and space use with camera and telemetry data. Ecology 2022; 103:e3583. [PMID: 34767254 DOI: 10.1002/ecy.3583] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 08/09/2021] [Accepted: 09/03/2021] [Indexed: 12/13/2022]
Abstract
Studies of animal abundance and distribution are often conducted independently of research on movement, despite the important links between processes. Movement can cause rapid changes in spatial variation in density, and movement influences detection probability and therefore estimates of abundance from inferential methods such as spatial capture-recapture (SCR). Technological developments including camera traps and GPS telemetry have opened new opportunities for studying animal demography and movement, yet statistical models for these two data types have largely developed along parallel tracks. We present a hierarchical model in which both datasets are conditioned on a movement process for a clearly defined population. We fitted the model to data from 60 camera traps and 23,572 GPS telemetry locations collected on 17 male white-tailed deer in the Big Cypress National Preserve, Florida, USA during July 2015. Telemetry data were collected on a 3-4 h acquisition schedule, and we modeled the movement paths of all individuals in the region with a Ornstein-Uhlenbeck process that included individual-specific random effects. Two of the 17 deer with GPS collars were detected on cameras. An additional 20 male deer without collars were detected on cameras and individually identified based on their unique antler characteristics. Abundance was 126 (95% CI: 88-177) in the 228 km2 region, only slightly higher than estimated using a standard SCR model: 119 (84-168). The standard SCR model, however, was unable to describe individual heterogeneity in movement rates and space use as revealed by the joint model. Joint modeling allowed the telemetry data to inform the movement model and the SCR encounter model, while leveraging information in the camera data to inform abundance, distribution and movement. Unlike most existing methods for population-level inference on movement, the joint SCR-movement model can yield unbiased inferences even if non-uniform sampling is used to deploy transmitters. Potential extensions of the model include the addition of resource selection parameters, and relaxation of the closure assumption when interest lies in survival and recruitment. These developments would contribute to the emerging holistic framework for the study of animal ecology, one that uses modern technology and spatio-temporal statistics to learn about interactions between behavior and demography.
Collapse
Affiliation(s)
- Richard B Chandler
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia, 30602, USA
| | - Daniel A Crawford
- Caesar Kleberg Wildlife Research Institute at Texas A&M University-Kingsville, Kingsville, Texas, 78363, USA
| | - Elina P Garrison
- Florida Fish and Wildlife Conservation Commission, Gainesville, Florida, 32601, USA
| | - Karl V Miller
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia, 30602, USA
| | - Michael J Cherry
- Caesar Kleberg Wildlife Research Institute at Texas A&M University-Kingsville, Kingsville, Texas, 78363, USA
| |
Collapse
|
4
|
Twining JP, Lawton C, White A, Sheehy E, Hobson K, Montgomery WI, Lambin X. Restoring vertebrate predator populations can provide landscape-scale biological control of established invasive vertebrates: Insights from pine marten recovery in Europe. GLOBAL CHANGE BIOLOGY 2022; 28:5368-5384. [PMID: 35706099 PMCID: PMC9542606 DOI: 10.1111/gcb.16236] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 05/01/2022] [Accepted: 04/26/2022] [Indexed: 06/15/2023]
Abstract
Invasive species pose one of the greatest global threats to biodiversity. There has been a long history of importing coevolved natural enemies to act as biological control agents to try to suppress densities of invasive species, with historically limited success and frequent adverse impacts on native biodiversity. Our understanding of the processes and drivers of successful biological control has been focussed on invertebrates and is evidently limited and potentially ill-suited with respect to biological control of vertebrate populations. The restoration of native vertebrate predator populations provides a promising nature-based solution for slowing, halting, or even reversing the spread of some invasive vertebrates over spatial scales relevant to the management of wildlife populations. Here, we first review the growing literature and data from the pine marten-red and grey squirrel system in Europe. We synthesise a multi-decadal dataset to show that the recovery of a native predator has resulted in rapid, landscape-scale declines of an established invasive species. We then use the model system, predator-prey interaction theory, and examples from the literature to develop ecological theory relating to natural biological control in vertebrates and evolutionary processes in native-invasive predator-prey interactions. We find support for the hypotheses that evolutionary naivety of invasive species to native predators and lack of local refuges results in higher predation of naive compared to coevolved prey. We apply lessons learnt from the marten-squirrel model system to examine the plausibility of specific native predator solutions to some of the Earth's most devastating invasive vertebrates. Given the evidence, we conclude that depletion of vertebrate predator populations has increased ecosystem vulnerability to invasions and thus facilitated the spread of invasive species. Therefore, restoration of vertebrate predator populations is an underappreciated, fundamental, nature-based solution to the crisis of invasive species and should be a priority for vertebrate invasive species management globally.
Collapse
Affiliation(s)
- Joshua P. Twining
- Department of Natural ResourcesCornell UniversityIthacaNew YorkUSA
- School of Biological SciencesQueen's UniversityBelfastUK
| | - Colin Lawton
- School of Natural Sciences, Ryan InstituteNational University of Ireland GalwayGalwayIreland
| | - Andy White
- Maxwell Institute for Mathematical Sciences, Department of MathematicsHeriot‐Watt UniversityEdinburghUK
| | - Emma Sheehy
- School of Natural Sciences, Ryan InstituteNational University of Ireland GalwayGalwayIreland
| | - Keziah Hobson
- School of Biological SciencesUniversity of AberdeenAberdeenUK
| | | | - Xavier Lambin
- School of Biological SciencesUniversity of AberdeenAberdeenUK
| |
Collapse
|
5
|
Schmidt GM, Graves TA, Pederson JC, Carroll SL. Precision and bias of spatial capture-recapture estimates: A multi-site, multi-year Utah black bear case study. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2022; 32:e2618. [PMID: 35368131 PMCID: PMC9287071 DOI: 10.1002/eap.2618] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 01/13/2022] [Accepted: 01/24/2022] [Indexed: 06/14/2023]
Abstract
Spatial capture-recapture (SCR) models are powerful analytical tools that have become the standard for estimating abundance and density of wild animal populations. When sampling populations to implement SCR, the number of unique individuals detected, total recaptures, and unique spatial relocations can be highly variable. These sample sizes influence the precision and accuracy of model parameter estimates. Testing the performance of SCR models with sparse empirical data sets typical of low-density, wide-ranging species can inform the threshold at which a more integrated modeling approach with additional data sources or additional years of monitoring may be required to achieve reliable, precise parameter estimates. Using a multi-site, multi-year Utah black bear (Ursus americanus) capture-recapture data set, we evaluated factors influencing the uncertainty of SCR structural parameter estimates, specifically density, detection, and the spatial scale parameter, sigma. We also provided some of the first SCR density estimates for Utah black bear populations, which ranged from 3.85 to 74.33 bears/100 km2 . Increasing total detections decreased the uncertainty of density estimates, whereas an increasing number of total recaptures and individuals with recaptures decreased the uncertainty of detection and sigma estimates, respectively. In most cases, multiple years of data were required for precise density estimates (<0.2 coefficient of variation [CV]). Across study areas there was an average decline in CV of 0.07 with the addition of another year of data. One sampled population with very high estimated bear density had an atypically low number of spatial recaptures relative to total recaptures, apparently inflating density estimates. A complementary simulation study used to assess estimate bias suggested that when <30% of recaptured individuals were spatially recaptured, density estimates were unreliable and ranged widely, in some cases to >3 times the simulated density. Additional research could evaluate these requirements for other density scenarios. Large numbers of individuals detected, numbers of spatial recaptures, and precision alone may not be sufficient indicators of parameter estimate reliability. We provide an evaluation of simple summary statistics of capture-recapture data sets that can provide an early signal of the need to alter sampling design or collect auxiliary data before model implementation to improve estimate precision and accuracy.
Collapse
Affiliation(s)
- Greta M. Schmidt
- Department of BiologySan Diego State UniversitySan DiegoCaliforniaUSA
| | - Tabitha A. Graves
- U.S. Geological Survey, Northern Rocky Mountain Science CenterWest GlacierMontanaUSA
| | | | - Sarah L. Carroll
- Graduate Degree Program in EcologyColorado State UniversityFort CollinsColoradoUSA
| |
Collapse
|
6
|
Margenau LLS, Cherry MJ, Miller KV, Garrison EP, Chandler RB. Monitoring partially marked populations using camera and telemetry data. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2022; 32:e2553. [PMID: 35112750 DOI: 10.1002/eap.2553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 10/26/2021] [Indexed: 06/14/2023]
Abstract
Long-term monitoring is an important component of effective wildlife conservation. However, many methods for estimating density are too costly or difficult to implement over large spatial and temporal extents. Recently developed spatial mark-resight (SMR) models are increasingly being applied as a cost-effective method to estimate density when data include detections of both marked and unmarked individuals. We developed a generalized SMR model that can accommodate long-term camera data and auxiliary telemetry data for improved spatiotemporal inference in monitoring efforts. The model can be applied in two stages, with detection parameters estimated in the first stage using telemetry data and camera detections of instrumented individuals. Density is estimated in the second stage using camera data, with all individuals treated as unmarked. Serial correlation in detection and density parameters is accounted for using time-series models. The two-stage approach reduces computational demands and facilitates the application to large data sets from long-term monitoring initiatives. We applied the model to 3 years (2015-2017) of white-tailed deer (Odocoileus virginianus) data collected in three study areas of the Big Cypress Basin, Florida, USA. In total, 59 females marked with ear tags and fitted with GPS-telemetry collars were detected along with unmarked females on 180 remote cameras. Most of the temporal variation in density was driven by seasonal fluctuations, but one study area exhibited a slight population decline during the monitoring period. Modern technologies such as camera traps provide novel possibilities for long-term monitoring, but the resulting massive data sets, which are subject to unique sources of observation error, have posed analytical challenges. The two-stage spatial mark-resight framework provides a solution with lower computational demands than joint SMR models, allowing for easier implementation in practice. In addition, after detection parameters have been estimated, the model may be used to estimate density even if no synchronous auxiliary information on marked individuals is available, which is often the case in long-term monitoring.
Collapse
Affiliation(s)
- Lydia L S Margenau
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia, USA
| | - Michael J Cherry
- Caesar Kleberg Wildlife Research Institute, Texas A&M University-Kingsville, Kingsville, Texas, USA
| | - Karl V Miller
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia, USA
| | - Elina P Garrison
- Florida Fish and Wildlife Conservation Commission, Gainesville, Florida, USA
| | - Richard B Chandler
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia, USA
| |
Collapse
|
7
|
Review of puma density estimates reveals sources of bias and variation, and the need for standardization. Glob Ecol Conserv 2022. [DOI: 10.1016/j.gecco.2022.e02109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
|
8
|
Reynolds‐Hogland M, Ramsey AB, Muench C, Pilgrim KL, Engkjer C, Erba G, Ramsey PW. Integrating video and genetic data to estimate annual age‐structured apparent survival of American black bears. POPUL ECOL 2022. [DOI: 10.1002/1438-390x.12122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
| | | | | | - Kristine L. Pilgrim
- USDA National Genomics Center Rocky Mountain Research Station Missoula Montana USA
| | - Cory Engkjer
- USDA National Genomics Center Rocky Mountain Research Station Missoula Montana USA
| | | | | |
Collapse
|
9
|
Alexander PD, Craighead DJ. A novel camera trapping method for individually identifying pumas by facial features. Ecol Evol 2022; 12:e8536. [PMID: 35136565 PMCID: PMC8809426 DOI: 10.1002/ece3.8536] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 11/26/2021] [Accepted: 12/22/2021] [Indexed: 11/08/2022] Open
Abstract
Camera traps (CTs), used in conjunction with capture-mark-recapture analyses (CMR; photo-CMR), are a valuable tool for estimating abundances of rare and elusive wildlife. However, a critical requirement of photo-CMR is that individuals are identifiable in CT images (photo-ID). Thus, photo-CMR is generally limited to species with conspicuous pelage patterns (e.g., stripes or spots) using lateral-view images from CTs stationed along travel paths. Pumas (Puma concolor) are an elusive species for which CTs are highly effective at collecting image data, but their suitability to photo-ID is controversial due to their lack of pelage markings. For a wide range of taxa, facial features are useful for photo-ID, but this method has generally been limited to images collected with traditional handheld cameras. Here, we evaluate the feasibility of using puma facial features for photo-ID in a CT framework. We consider two issues: (1) the ability to capture puma facial images using CTs, and (2) whether facial images improve human ability to photo-ID pumas. We tested a novel CT accessory that used light and sound to attract the attention of pumas, thereby collecting face images for use in photo-ID. Face captures rates increased at CTs that included the accessory (n = 208, χ 2 = 43.23, p ≤ .001). To evaluate if puma faces improve photo-ID, we measured the inter-rater agreement of 5 independent assessments of photo-ID for 16 of our puma face capture events. Agreement was moderate to good (Fleiss' kappa = 0.54, 95% CI = 0.48-0.60), and was 92.90% greater than a previously published kappa using conventional CT methods. This study is the first time that such a technique has been used for photo-ID, and we believe a promising demonstration of how photo-ID may be feasible for an elusive but unmarked species.
Collapse
|
10
|
Doran‐Myers D, Kenney AJ, Krebs CJ, Lamb CT, Menzies AK, Murray D, Studd EK, Whittington J, Boutin S. Density estimates for Canada lynx vary among estimation methods. Ecosphere 2021. [DOI: 10.1002/ecs2.3774] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- D. Doran‐Myers
- Biological Sciences Centre University of Alberta Edmonton Alberta T6G 2E9 Canada
| | - A. J. Kenney
- Department of Zoology University of British Columbia Vancouver British Columbia V6T 1Z4 Canada
| | - C. J. Krebs
- Department of Zoology University of British Columbia Vancouver British Columbia V6T 1Z4 Canada
| | - C. T. Lamb
- Biological Sciences Centre University of Alberta Edmonton Alberta T6G 2E9 Canada
| | - A. K. Menzies
- Department of Natural Resource Sciences McGill University Montréal Québec H9X 3V9 Canada
| | - D. Murray
- Department of Biology Trent University Peterborough Ontario K0L 2H0 Canada
| | - E. K. Studd
- Department of Natural Resource Sciences McGill University Montréal Québec H9X 3V9 Canada
| | - J. Whittington
- Parks Canada Banff National Park Resource Conservation Banff Alberta T1L 1K2 Canada
| | - S. Boutin
- Biological Sciences Centre University of Alberta Edmonton Alberta T6G 2E9 Canada
| |
Collapse
|
11
|
Brommer JE, Poutanen J, Pusenius J, Wikström M. Estimating preharvest density, adult sex ratio, and fecundity of white-tailed deer using noninvasive sampling techniques. Ecol Evol 2021; 11:14312-14326. [PMID: 34707857 PMCID: PMC8525134 DOI: 10.1002/ece3.8149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 09/03/2021] [Accepted: 09/06/2021] [Indexed: 11/08/2022] Open
Abstract
Adult sex ratio and fecundity (juveniles per female) are key population parameters in sustainable wildlife management, but inferring these requires abundance estimates of at least three age/sex classes of the population (male and female adults and juveniles). Prior to harvest, we used an array of 36 wildlife camera traps during 2 and 3 weeks in the early autumn of 2016 and 2017, respectively. We recorded white-tailed deer adult males, adult females, and fawns from the pictures. Simultaneously, we collected fecal DNA (fDNA) from 92 20 m × 20 m plots placed in 23 clusters of four plots between the camera traps. We identified individuals from fDNA samples with microsatellite markers and estimated the total sex ratio and population density using spatial capture-recapture (SCR). The fDNA-SCR analysis concluded equal sex ratio in the first year and female bias in the second year, and no difference in space use between sexes (fawns and adults combined). Camera information was analyzed in a spatial capture (SC) framework assuming an informative prior for animals' space use, either (a) as estimated by fDNA-SCR (same for all age/sex classes), (b) as assumed from the literature (space use of adult males larger than adult females and fawns), or (c) by inferring adult male space use from individually identified males from the camera pictures. These various SC approaches produced plausible inferences on fecundity, but also inferred total density to be lower than the estimate provided by fDNA-SCR in one of the study years. SC approaches where adult male and female were allowed to differ in their space use suggested the population had a female-biased adult sex ratio. In conclusion, SC approaches allowed estimating the preharvest population parameters of interest and provided conservative density estimates.
Collapse
|
12
|
Abstract
Abstract
Spatial capture–recapture models have been widely used to estimate densities of species where individuals can be uniquely identified, but alternatives have been developed for estimation of densities for unmarked populations. In this study we used camera-trap records from 2018 to estimate densities of a species that does not always have individually identifiable marks, Baird's tapir Tapirus bairdii, in the Sierra Madre de Chiapas, southern Mexico. We compared the performance of the spatial capture–recapture model with spatial mark–resight and random encounter models. The density of Baird's tapir did not differ significantly between the three models. The estimate of density was highest using the random encounter model (26/100 km2, 95% CI 12–41) and lowest using the capture–recapture model (8/100 km2, 95% CI 4–16). The estimate from the spatial mark–resight model was 10/100 km2 (95% CI 8–14), which had the lowest coefficient of variation, indicating a higher precision than with the other models. Using a second set of camera-trap data, collected in 2015–2016, we created occupancy models and extrapolated density to areas with potential occupancy of Baird's tapir, to generate a population estimate for the whole Sierra Madre de Chiapas. Our findings indicate the need to strengthen, and possibly expand, the protected areas of southern Mexico and to develop an action plan to ensure the conservation of Baird's tapir.
Collapse
|
13
|
Loonam KE, Lukacs PM, Ausband DE, Mitchell MS, Robinson HS. Assessing the robustness of time-to-event models for estimating unmarked wildlife abundance using remote cameras. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2021; 31:e02388. [PMID: 34156123 DOI: 10.1002/eap.2388] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 01/04/2021] [Accepted: 02/04/2021] [Indexed: 06/13/2023]
Abstract
Recently developed methods, including time-to-event and space-to-event models, estimate the abundance of unmarked populations from encounter rates with camera trap arrays, addressing a gap in noninvasive wildlife monitoring. However, estimating abundance from encounter rates relies on assumptions that can be difficult to meet in the field, including random movement, population closure, and an accurate estimate of movement speed. Understanding how these models respond to violation of these assumptions will assist in making them more applicable in real-world settings. We used simulated walk models to test the effects of violating the assumptions of the time-to-event model under four scenarios: (1) incorrectly estimating movement speed, (2) violating closure, (3) individuals moving within simplified territories (i.e., movement restricted to partially overlapping circles), (4) and individuals clustering in preferred habitat. The time-to-event model was robust to closure violations, territoriality, and clustering when cameras were placed randomly. However, the model failed to estimate abundance accurately when movement speed was incorrectly estimated or cameras were placed nonrandomly with respect to habitat. We show that the time-to-event model can provide unbiased estimates of abundance when some assumptions that are commonly violated in wildlife studies are not met. Having a robust method for estimating the abundance of unmarked populations with remote cameras will allow practitioners to monitor a more diverse array of populations noninvasively. With the time-to-event model, placing cameras randomly with respect to animal movement and accurately estimating movement speed allows unbiased estimation of abundance. The model is robust to violating the other assumptions we tested.
Collapse
Affiliation(s)
- Kenneth E Loonam
- Montana Cooperative Wildlife Research Unit, Wildlife Biology Program, W.A. Franke College of Forestry and Conservation, University of Montana, Natural Sciences Room 205, Missoula, Montana, 59812, USA
| | - Paul M Lukacs
- Wildlife Biology Program, W.A. Franke College of Forestry and Conservation, University of Montana, 32 Campus Drive, Missoula, Montana, 59812, USA
| | - David E Ausband
- Idaho Department of Fish and Game, 2885 West Kathleen Avenue, Coeur d'Alene, Idaho, 83815, USA
| | - Michael S Mitchell
- U.S. Geological Survey, Montana Cooperative Wildlife Research Unit, Natural Sciences Room 205, University of Montana, Missoula, Montana, 59812, USA
| | - Hugh S Robinson
- Panthera and Wildlife Biology Program, W.A. Franke College of Forestry and Conservation, University of Montana, Natural Sciences Room 205, Missoula, Montana, 59812, USA
| |
Collapse
|
14
|
Mitchell CI, Shoemaker KT, Esque TC, Vandergast AG, Hromada SJ, Dutcher KE, Heaton JS, Nussear KE. Integrating telemetry data at several scales with spatial capture–recapture to improve density estimates. Ecosphere 2021. [DOI: 10.1002/ecs2.3689] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Corey I. Mitchell
- Department of Geography University of Nevada, Reno 1664 North Virginia Street Reno Nevada 89557 USA
| | - Kevin T. Shoemaker
- Department of Natural Resources and Environmental Science University of Nevada, Reno 1664 North Virginia Street Reno Nevada 89557 USA
| | - Todd C. Esque
- U.S. Geological Survey, Western Ecological Research Center 160 North Stephanie Street Henderson Nevada 89074 USA
| | - Amy G. Vandergast
- U.S. Geological Survey, Western Ecological Research Center 4165 Spruance Road Suite 200 San Diego California 92101 USA
| | - Steven J. Hromada
- Department of Geography University of Nevada, Reno 1664 North Virginia Street Reno Nevada 89557 USA
| | - Kirsten E. Dutcher
- Department of Geography University of Nevada, Reno 1664 North Virginia Street Reno Nevada 89557 USA
| | - Jill S. Heaton
- Department of Geography University of Nevada, Reno 1664 North Virginia Street Reno Nevada 89557 USA
| | - Kenneth E. Nussear
- Department of Geography University of Nevada, Reno 1664 North Virginia Street Reno Nevada 89557 USA
| |
Collapse
|
15
|
Kukielka EA, MartÍnez‐lÓpez B, Ballweber LR, Buttke D, Patrick K, Wold EB, Mazur R. Spatial‐Mark‐Resight Model to Estimate Raccoon Abundance in Yosemite Valley, California. WILDLIFE SOC B 2021. [DOI: 10.1002/wsb.1182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Esther A. Kukielka
- Center for Animal Disease Modeling and Surveillance, Dept. Medicine & Epidemiology, School of Veterinary Medicine University of California Davis, One Shields Avenue, 2108 Tupper Hall Davis CA 95616 USA
| | - Beatriz MartÍnez‐lÓpez
- Center for Animal Disease Modeling and Surveillance, Dept. Medicine & Epidemiology, School of Veterinary Medicine University of California Davis, One Shields Avenue, 2108 Tupper Hall Davis CA 95616 USA
| | - Lora R. Ballweber
- College of Veterinary Medicine and Biomedical Sciences Colorado State University Fort Collins 80523‐1682
| | - Danielle Buttke
- Biological Resources Division/Wildlife Health Branch and Office of Public Health National Park Service 1201 Oakridge Drive, Suite 200 Fort Collins CO 80525
| | - Katie Patrick
- Division of Resources Management and Science Yosemite National Park 9039 Village Drive Yosemite CA 95389 USA
| | - E. Binta Wold
- Division of Resources Management and Science Yosemite National Park 9039 Village Drive Yosemite CA 95389 USA
| | - Rachel Mazur
- Division of Resources Management and Science Yosemite National Park 5083 Foresta Road El Portal CA 95318 USA
| |
Collapse
|
16
|
Blount JD, Chynoweth MW, Green AM, Şekercioğlu ÇH. Review: COVID-19 highlights the importance of camera traps for wildlife conservation research and management. BIOLOGICAL CONSERVATION 2021; 256:108984. [PMID: 36531528 PMCID: PMC9746925 DOI: 10.1016/j.biocon.2021.108984] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 01/11/2021] [Accepted: 01/16/2021] [Indexed: 05/26/2023]
Abstract
COVID-19 has altered many aspects of everyday life. For the scientific community, the pandemic has called upon investigators to continue work in novel ways, curtailing field and lab research. However, this unprecedented situation also offers an opportunity for researchers to optimize and further develop available field methods. Camera traps are one example of a tool used in science to answer questions about wildlife ecology, conservation, and management. Camera traps have long battery lives, lasting more than a year in certain cases, and photo storage capacity, with some models capable of wirelessly transmitting images from the field. This allows researchers to deploy cameras without having to check them for up to a year or more, making them an ideal field research tool during restrictions on in-person research activities such as COVID-19 lockdowns. As technological advances allow cameras to collect increasingly greater numbers of photos and videos, the analysis techniques for large amounts of data are evolving. Here, we describe the most common research questions suitable for camera trap studies and their importance for biodiversity conservation. As COVID-19 continues to affect how people interact with the natural environment, we discuss novel questions for which camera traps can provide insights on. We conclude by summarizing the results of a systematic review of camera trap studies, providing data on target taxa, geographic distribution, publication rate, and publication venues to help researchers planning to use camera traps in response to the current changes in human activity.
Collapse
Affiliation(s)
- J David Blount
- School of Biological Sciences, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112-0840, USA
| | - Mark W Chynoweth
- Department of Wildland Resources, Utah State University, Uintah Basin, 320 North Aggie Blvd., Vernal, UT 84078, USA
| | - Austin M Green
- School of Biological Sciences, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112-0840, USA
| | - Çağan H Şekercioğlu
- School of Biological Sciences, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112-0840, USA
- College of Sciences, Koç University, Rumelifeneri, İstanbul, Sarıyer, Turkey
| |
Collapse
|
17
|
Proffitt KM, Garrott R, Gude JA, Hebblewhite M, Jimenez B, Paterson JT, Rotella J. Integrated Carnivore‐Ungulate Management: A Case Study in West‐Central Montana. WILDLIFE MONOGRAPHS 2020. [DOI: 10.1002/wmon.1056] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Kelly M. Proffitt
- Montana Department of Fish Wildlife and Parks 1400 South 19th Street Bozeman MT 59718 USA
| | - Robert Garrott
- Department of Ecology, Fish and Wildlife Ecology and Management Program Montana State University 310 Lewis Hall Bozeman MT 59718 USA
| | - Justin A. Gude
- Montana Department of Fish Wildlife and Parks 1420 E 6th Ave Helena MT 59620 USA
| | - Mark Hebblewhite
- Wildlife Biology Program, Department of Ecosystem and Conservation Sciences, W.A. Franke College of Forestry and Conservation University of Montana Missoula MT 59812 USA
| | - Benjamin Jimenez
- Montana Department of Fish Wildlife and Parks 3201 Spurgin Road Missoula MT 59804 USA
| | - J. Terrill Paterson
- Department of Ecology Montana State University 310 Lewis Hall Bozeman MT 59718 USA
| | - Jay Rotella
- Department of Ecology Montana State University 310 Lewis Hall Bozeman MT 59718 USA
| |
Collapse
|
18
|
Corcoran E, Denman S, Hamilton G. New technologies in the mix: Assessing N-mixture models for abundance estimation using automated detection data from drone surveys. Ecol Evol 2020; 10:8176-8185. [PMID: 32788970 PMCID: PMC7417234 DOI: 10.1002/ece3.6522] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 05/16/2020] [Accepted: 06/02/2020] [Indexed: 11/16/2022] Open
Abstract
Reliable estimates of abundance are critical in effectively managing threatened species, but the feasibility of integrating data from wildlife surveys completed using advanced technologies such as remotely piloted aircraft systems (RPAS) and machine learning into abundance estimation methods such as N-mixture modeling is largely unknown due to the unique sources of detection errors associated with these technologies.We evaluated two modeling approaches for estimating the abundance of koalas detected automatically in RPAS imagery: (a) a generalized N-mixture model and (b) a modified Horvitz-Thompson (H-T) estimator method combining generalized linear models and generalized additive models for overall probability of detection, false detection, and duplicate detection. The final estimates from each model were compared to the true number of koalas present as determined by telemetry-assisted ground surveys.The modified H-T estimator approach performed best, with the true count of koalas captured within the 95% confidence intervals around the abundance estimates in all 4 surveys in the testing dataset (n = 138 detected objects), a particularly strong result given the difficulty in attaining accuracy found with previous methods.The results suggested that N-mixture models in their current form may not be the most appropriate approach to estimating the abundance of wildlife detected in RPAS surveys with automated detection, and accurate estimates could be made with approaches that account for spurious detections.
Collapse
Affiliation(s)
- Evangeline Corcoran
- School of Earth, Environmental and Biological SciencesQueensland University of Technology (QUT)BrisbaneQLDAustralia
| | - Simon Denman
- School of Electrical Engineering and Computer ScienceQueensland University of Technology (QUT)BrisbaneQLDAustralia
| | - Grant Hamilton
- School of Earth, Environmental and Biological SciencesQueensland University of Technology (QUT)BrisbaneQLDAustralia
| |
Collapse
|
19
|
Smith JA, Suraci JP, Hunter JS, Gaynor KM, Keller CB, Palmer MS, Atkins JL, Castañeda I, Cherry MJ, Garvey PM, Huebner SE, Morin DJ, Teckentrup L, Weterings MJA, Beaudrot L. Zooming in on mechanistic predator-prey ecology: Integrating camera traps with experimental methods to reveal the drivers of ecological interactions. J Anim Ecol 2020; 89:1997-2012. [PMID: 32441766 DOI: 10.1111/1365-2656.13264] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 03/10/2020] [Indexed: 11/27/2022]
Abstract
Camera trap technology has galvanized the study of predator-prey ecology in wild animal communities by expanding the scale and diversity of predator-prey interactions that can be analysed. While observational data from systematic camera arrays have informed inferences on the spatiotemporal outcomes of predator-prey interactions, the capacity for observational studies to identify mechanistic drivers of species interactions is limited. Experimental study designs that utilize camera traps uniquely allow for testing hypothesized mechanisms that drive predator and prey behaviour, incorporating environmental realism not possible in the laboratory while benefiting from the distinct capacity of camera traps to generate large datasets from multiple species with minimal observer interference. However, such pairings of camera traps with experimental methods remain underutilized. We review recent advances in the experimental application of camera traps to investigate fundamental mechanisms underlying predator-prey ecology and present a conceptual guide for designing experimental camera trap studies. Only 9% of camera trap studies on predator-prey ecology in our review use experimental methods, but the application of experimental approaches is increasing. To illustrate the utility of camera trap-based experiments using a case study, we propose a study design that integrates observational and experimental techniques to test a perennial question in predator-prey ecology: how prey balance foraging and safety, as formalized by the risk allocation hypothesis. We discuss applications of camera trap-based experiments to evaluate the diversity of anthropogenic influences on wildlife communities globally. Finally, we review challenges to conducting experimental camera trap studies. Experimental camera trap studies have already begun to play an important role in understanding the predator-prey ecology of free-living animals, and such methods will become increasingly critical to quantifying drivers of community interactions in a rapidly changing world. We recommend increased application of experimental methods in the study of predator and prey responses to humans, synanthropic and invasive species, and other anthropogenic disturbances.
Collapse
Affiliation(s)
- Justine A Smith
- Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, CA, USA
| | - Justin P Suraci
- Environmental Studies Department, Center for Integrated Spatial Research, University of California, Santa Cruz, CA, USA
| | - Jennifer S Hunter
- Hastings Natural History Reservation, University of California, Berkeley, CA, USA
| | - Kaitlyn M Gaynor
- National Center for Ecological Analysis and Synthesis, Santa Barbara, CA, USA
| | - Carson B Keller
- Department of Biology, California State University, Northridge, CA, USA
| | - Meredith S Palmer
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Justine L Atkins
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Irene Castañeda
- Centre d'Ecologie et des Sciences de la Conservation (CESCO UMR 7204), Sorbonne Universités, MNHN, CNRS, UPMC, Paris, France.,Ecologie, Systématique et Evolution, UMR CNRS 8079, Université Paris-Sud, Orsay Cedex, France
| | - Michael J Cherry
- Caesar Kleberg Wildlife Research Institute, Texas A&M University - Kingsville, Kingsville, TX, USA
| | | | - Sarah E Huebner
- College of Biological Sciences, University of Minnesota, St. Paul, MN, USA
| | - Dana J Morin
- Department of Wildlife, Fisheries, & Aquaculture, Mississippi State University, Starkville, MS, USA
| | - Lisa Teckentrup
- BioMove Research Training Group, University of Potsdam, Potsdam, Germany
| | - Martijn J A Weterings
- Wildlife Ecology and Conservation Group, Wageningen University, Wageningen, The Netherlands.,Department of Wildlife Management, Van Hall Larenstein University of Applied Sciences, Leeuwarden, The Netherlands
| | - Lydia Beaudrot
- Department of BioSciences, Program in Ecology and Evolutionary Biology, Rice University, Houston, TX, USA
| |
Collapse
|
20
|
Linden DW, Green DS, Chelysheva EV, Mandere SM, Dloniak SM. Challenges and opportunities in population monitoring of cheetahs. POPUL ECOL 2020. [DOI: 10.1002/1438-390x.12052] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Daniel W. Linden
- NOAA National Marine Fisheries Service, Greater Atlantic Regional Fisheries Office Gloucester Massachusetts USA
| | - David S. Green
- Institute for Natural Resources Oregon State University Corvallis Oregon USA
| | | | | | - Stephanie M. Dloniak
- Department of Integrative Biology Michigan State University East Lansing Michigan USA
| |
Collapse
|
21
|
Sato Y, Nakamura H, Kyoko K, Sekiguchi M, Ishibashi Y, Itoh T. Evaluation of the Effectiveness of Scented Wooden Posts for DNA Hair Snagging of Brown Bears. MAMMAL STUDY 2020. [DOI: 10.3106/ms2018-0045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Yoshikazu Sato
- Graduate School of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa 252-8510, Japan
| | - Hidetsugu Nakamura
- Graduate School of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa 252-8510, Japan
| | - Kobayashi Kyoko
- Urahoro Brown Bear Research Group, Urahoro, Hokkaido 089-5692, Japan
| | - Masanao Sekiguchi
- Urahoro Brown Bear Research Group, Urahoro, Hokkaido 089-5692, Japan
| | - Yuki Ishibashi
- Urahoro Brown Bear Research Group, Urahoro, Hokkaido 089-5692, Japan
| | - Tetsuji Itoh
- Graduate School of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa 252-8510, Japan
| |
Collapse
|
22
|
Barrueto M, Sawaya M, Clevenger A. Low wolverine (Gulo gulo) density in a national park complex of the Canadian Rocky Mountains. CAN J ZOOL 2020. [DOI: 10.1139/cjz-2019-0165] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Large carnivores are sensitive to human-caused extirpation due to large home ranges, low population densities, and low reproductive rates. Protected areas help maintain populations by acting as sources, but human-caused mortality, habitat displacement, and edge effects occurring at protected area boundaries may reduce that function. The national parks Banff, Yoho, and Kootenay in the Canadian Rocky Mountains are refugia for large carnivores, including wolverines (Gulo gulo (Linnaeus, 1758)). Despite growing conservation concern, empirical baseline population data for wolverines remain scarce throughout their range, including most of Canada. We hypothesized (i) that in these national parks, wolverine density matched values expected for high-quality habitat, and (ii) that edge effects decreased density towards park boundaries. We conducted systematic non-invasive genetic sampling surveys covering >7000 km2 (2011 and 2013). Using spatial capture–recapture models, we estimated mean (±SE) female (1.5 ± 0.3 and 1.4 ± 0.3 wolverine/1000 km2), male (1.8 ± 0.4 and 1.5 ± 0.3 wolverine/1000 km2), and combined (3.3 ± 0.5 and 3.0 ± 0.4 wolverine/1000 km2) densities for 2011 and 2013, respectively. These estimates were lower than predictions based on density extrapolation from nearby high-quality habitat, and density decreased towards park boundaries. To benefit the population, we recommend creating buffer zones around parks that protect female habitat and prohibit harvest.
Collapse
Affiliation(s)
- M. Barrueto
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada
| | - M.A. Sawaya
- Sinopah Wildlife Research Associates, 127 North Higgins, Suite 310, Missoula, MT 59802, USA
| | - A.P. Clevenger
- Western Transportation Institute, Montana State University, P.O. Box 174250, Bozeman, MT 59717-4250, USA
| |
Collapse
|
23
|
Lincoln AE, Wirsing AJ, Quinn TP. Long-term use of non-invasive sampling methods: does successful sampling of brown bears by hair snares and camera traps change over time? WILDLIFE RESEARCH 2020. [DOI: 10.1071/wr19156] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Abstract
Context Non-invasive sampling methods are widely used by ecologists to collect animal hair, images, tissue or signs. Sampling devices are imperfect, and collection success may vary over time owing to behavioural changes in study organisms or other factors. If collection success decreases, the utility of non-invasive sampling devices for longitudinal studies that rely on consistency may be compromised.
Aims Our primary objectives were to evaluate whether collection success of brown bear (Ursus arctos) hair by using hair snares and camera traps changed over time, and whether hair- and image-collection success was influenced by bear activity around the sampling site.
Methods We paired non-invasive sampling by hair snares with motion-activated cameras at six streams in Alaska over 4–6 years, so as to evaluate how often brown bears left samples on wires or were photographed by cameras, and whether this sampling success changed over time. Changes in sampling success were evaluated in the context of bear activity per sampling period as determined by camera data (number of bear–wire encounters) or hair snare (number of barbs with hair); genetic analyses allowed us to evaluate whether the same bears were sampled repeatedly.
Key results Overall, hair was collected in 78% and images in 73% of 2-day sampling periods when bears visited sites, and we observed no substantial change in the probability of successful sampling over time at 11 sites. The number of bear–wire encounters was positively correlated with the number of hair samples collected, as would be expected if sampling rates remained constant over time, and individual bears with previous wire experience were sampled in multiple years.
Conclusions Overall, the results indicated that sampling success by using hair snare and camera trap showed substantial interannual variability, but changes over time were not consistently identified across sites. Among-site variation in sampling success highlighted the importance of accounting for site-specific differences in sampling success, and neither method sampled unfailingly.
Implications Sampling by wires and cameras remained effective over time, suggesting that these non-invasive sampling methods may be successfully employed in long-term studies.
Collapse
|
24
|
Kelt DA, Heske EJ, Lambin X, Oli MK, Orrock JL, Ozgul A, Pauli JN, Prugh LR, Sollmann R, Sommer S. Advances in population ecology and species interactions in mammals. J Mammal 2019. [DOI: 10.1093/jmammal/gyz017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
AbstractThe study of mammals has promoted the development and testing of many ideas in contemporary ecology. Here we address recent developments in foraging and habitat selection, source–sink dynamics, competition (both within and between species), population cycles, predation (including apparent competition), mutualism, and biological invasions. Because mammals are appealing to the public, ecological insight gleaned from the study of mammals has disproportionate potential in educating the public about ecological principles and their application to wise management. Mammals have been central to many computational and statistical developments in recent years, including refinements to traditional approaches and metrics (e.g., capture-recapture) as well as advancements of novel and developing fields (e.g., spatial capture-recapture, occupancy modeling, integrated population models). The study of mammals also poses challenges in terms of fully characterizing dynamics in natural conditions. Ongoing climate change threatens to affect global ecosystems, and mammals provide visible and charismatic subjects for research on local and regional effects of such change as well as predictive modeling of the long-term effects on ecosystem function and stability. Although much remains to be done, the population ecology of mammals continues to be a vibrant and rapidly developing field. We anticipate that the next quarter century will prove as exciting and productive for the study of mammals as has the recent one.
Collapse
Affiliation(s)
- Douglas A Kelt
- Department of Wildlife, Fish, & Conservation Biology, University of California, Davis, CA, USA
| | - Edward J Heske
- Museum of Southwestern Biology, University of New Mexico, Albuquerque, NM, USA
| | - Xavier Lambin
- School of Biological Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Madan K Oli
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL, USA
| | - John L Orrock
- Department of Integrative Biology, University of Wisconsin, Madison, WI, USA
| | - Arpat Ozgul
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Jonathan N Pauli
- Department of Forest and Wildlife Ecology, University of Wisconsin, Madison, WI, USA
| | - Laura R Prugh
- School of Environmental and Forest Sciences, University of Washington, Seattle, WA, USA
| | - Rahel Sollmann
- Department of Wildlife, Fish, & Conservation Biology, University of California, Davis, CA, USA
| | - Stefan Sommer
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| |
Collapse
|
25
|
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.
Collapse
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
| |
Collapse
|
26
|
Paterson JT, Proffitt K, Jimenez B, Rotella J, Garrott R. Simulation-based validation of spatial capture-recapture models: A case study using mountain lions. PLoS One 2019; 14:e0215458. [PMID: 31002709 PMCID: PMC6474654 DOI: 10.1371/journal.pone.0215458] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 04/02/2019] [Indexed: 11/19/2022] Open
Abstract
Spatial capture-recapture (SCR) models have improved the ability to estimate densities of rare and elusive animals. However, SCR models have seldom been validated even as model formulations diversify and expand to incorporate new sampling methods and/or additional sources of information on model parameters. Information on the relationship between encounter probabilities, sources of additional information, and the reliability of density estimates, is rare but crucial to assessing reliability of SCR-based estimates. We used a simulation-based approach that incorporated prior empirical work to assess the accuracy and precision of density estimates from SCR models using spatially unstructured sampling. To assess the consequences of sparse data and potential sources of bias, we simulated data under six scenarios corresponding to three different levels of search effort and two levels of correlation between search effort and animal density. We then estimated density for each scenario using four models that included increasing amounts of information from harvested individuals and telemetry to evaluate the impact of additional sources of information. Model results were sensitive to the quantity of available information: density estimates based on low search effort were biased high and imprecise, whereas estimates based on high search effort were unbiased and precise. A correlation between search effort and animal density resulted in a positive bias in density estimates, though the bias decreased with increasingly informative datasets. Adding information from harvested individuals and telemetered individuals improved density estimates based on low and moderate effort but had negligible impact for datasets resulting from high effort. We demonstrated that density estimates from SCR models using spatially unstructured sampling are reliable when sufficient information is provided. Accurate density estimates can result if empirical-based simulations such as those presented here are used to develop study designs with appropriate amounts of effort and information sources.
Collapse
Affiliation(s)
- J. Terrill Paterson
- Department of Ecology, Montana State University, Bozeman, Montana, United States of America
- Montana Department of Fish, Wildlife and Parks, Bozeman, Montana, United States of America
- * E-mail:
| | - Kelly Proffitt
- Montana Department of Fish, Wildlife and Parks, Bozeman, Montana, United States of America
| | - Ben Jimenez
- Montana Department of Fish, Wildlife and Parks, Bozeman, Montana, United States of America
| | - Jay Rotella
- Department of Ecology, Montana State University, Bozeman, Montana, United States of America
| | - Robert Garrott
- Department of Ecology, Montana State University, Bozeman, Montana, United States of America
| |
Collapse
|
27
|
Murphy SM, Wilckens DT, Augustine BC, Peyton MA, Harper GC. Improving estimation of puma (Puma concolor) population density: clustered camera-trapping, telemetry data, and generalized spatial mark-resight models. Sci Rep 2019; 9:4590. [PMID: 30872785 PMCID: PMC6418282 DOI: 10.1038/s41598-019-40926-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 02/26/2019] [Indexed: 11/23/2022] Open
Abstract
Obtaining reliable population density estimates for pumas (Puma concolor) and other cryptic, wide-ranging large carnivores is challenging. Recent advancements in spatially explicit capture-recapture models have facilitated development of novel survey approaches, such as clustered sampling designs, which can provide reliable density estimation for expansive areas with reduced effort. We applied clustered sampling to camera-traps to detect marked (collared) and unmarked pumas, and used generalized spatial mark-resight (SMR) models to estimate puma population density across 15,314 km2 in the southwestern USA. Generalized SMR models outperformed conventional SMR models. Integrating telemetry data from collars on marked pumas with detection data from camera-traps substantially improved density estimates by informing cryptic activity (home range) center transiency and improving estimation of the SMR home range parameter. Modeling sex of unmarked pumas as a partially identifying categorical covariate further improved estimates. Our density estimates (0.84–1.65 puma/100 km2) were generally more precise (CV = 0.24–0.31) than spatially explicit estimates produced from other puma sampling methods, including biopsy darting, scat detection dogs, and regular camera-trapping. This study provides an illustrative example of the effectiveness and flexibility of our combined sampling and analytical approach for reliably estimating density of pumas and other wildlife across geographically expansive areas.
Collapse
Affiliation(s)
- Sean M Murphy
- Wildlife Management Division, New Mexico Department of Game & Fish, Santa Fe, 87507, USA. .,Department of Forestry and Natural Resources, University of Kentucky, Lexington, 40546, USA.
| | - David T Wilckens
- Wildlife Management Division, New Mexico Department of Game & Fish, Santa Fe, 87507, USA
| | - Ben C Augustine
- Atkinson Center for a Sustainable Future, Department of Natural Resources, Cornell University, Ithaca, 14853, USA
| | - Mark A Peyton
- Valles Caldera National Preserve, U.S. National Park Service, Jemez Springs, 87025, USA
| | - Glenn C Harper
- Department of Natural Resources, Pueblo of Santa Ana, Santa Ana Pueblo, 87004, USA
| |
Collapse
|
28
|
Carter A, Potts JM, Roshier DA. Toward reliable population density estimates of partially marked populations using spatially explicit mark-resight methods. Ecol Evol 2019; 9:2131-2141. [PMID: 30847098 PMCID: PMC6392348 DOI: 10.1002/ece3.4907] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 11/24/2018] [Accepted: 12/21/2018] [Indexed: 11/26/2022] Open
Abstract
Camera traps are used increasingly to estimate population density for elusive and difficult to observe species. A standard practice for mammalian surveys is to place cameras on roads, trails, and paths to maximize detections and/or increase efficiency in the field. However, for many species it is unclear whether track-based camera surveys provide reliable estimates of population density.Understanding how the spatial arrangement of camera traps affects population density estimates is of key interest to contemporary conservationists and managers given the rapid increase in camera-based wildlife surveys.We evaluated the effect of camera-trap placement, using several survey designs, on density estimates of a widespread mesopredator, the red fox Vulpes vulpes, over a two-year period in a semi-arid conservation reserve in south-eastern Australia. Further, we used the certainty in the identity and whereabouts of individuals (via GPS collars) to assess how resighting rates of marked foxes affect density estimates using maximum likelihood spatially explicit mark-resight methods.Fox detection rates were much higher at cameras placed on tracks compared with off-track cameras, yet in the majority of sessions, camera placement had relatively little effect on point estimates of density. However, for each survey design, the precision of density estimates varied considerably across sessions, influenced heavily by the absolute number of marked foxes detected, the number of times marked foxes was resighted, and the number of detection events of unmarked foxes.Our research demonstrates that the precision of population density estimates using spatially explicit mark-resight models is sensitive to resighting rates of identifiable individuals. Nonetheless, camera surveys based either on- or off-track can provide reliable estimates of population density using spatially explicit mark-resight models. This underscores the importance of incorporating information on the spatial behavior of the subject species when planning camera-trap surveys.
Collapse
Affiliation(s)
- Andrew Carter
- Australian Wildlife ConservancySubiaco EastWestern AustraliaAustralia
- Institute for Land, Water and SocietyCharles Sturt UniversityAlburyNew South WalesAustralia
| | | | - David A. Roshier
- Australian Wildlife ConservancySubiaco EastWestern AustraliaAustralia
- Centre for Ecosystem ScienceUniversity of New South WalesSydneyNew South WalesAustralia
| |
Collapse
|
29
|
Ramsey AB, Sawaya MA, Bullington LS, Ramsey PW. Individual identification via remote video verified by DNA analysis: a case study of the American black bear. WILDLIFE RESEARCH 2019. [DOI: 10.1071/wr18049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Context
Researchers and managers often use DNA analysis and remote photography to identify cryptic animals and estimate abundance. Remote video cameras are used less often but offer an increased ability to distinguish similar-looking individuals as well as to observe behavioural patterns that cannot be adequately captured with still photography. However, the use of this approach in species with minimally distinguishing marks has not been tested.
Aims
To determine the utility and accuracy of distinguishing characteristics of American black bears, Ursus americanus, observed on remote video for identifying individuals in an open population.
Methods
We compared individuals identified on video with individuals and their sex identified by DNA analysis of hairs collected from hair traps visited by the bears.
Key results
We found that remote video could be used to determine the number of male and female black bears sampled by the video cameras. Specifically, we matched 13 individual bear genotypes with 13 video identifications, one genotype for each individual. We correctly matched ~82% of video identifications with all 38 genotypes collected from hair traps.
Conclusions
We demonstrated that distinguishing characteristics of a cryptic animal in remote video can be used to accurately identify individuals. Remote video complements genetic analysis by providing information about habitat use and behaviour.
Implications
When remote video cameras can be used to identify individuals, a wealth of other information will subsequently be obtained. Multi-year video-based studies can show sex ratios, and relative physical condition; shed light on fine-scale habitat use, such as when and where animals feed and what they eat; and display social interactions and rare behaviours.
Collapse
|
30
|
Castañeda I, Pisanu B, Díaz M, Rézouki C, Baudry E, Chapuis JL, Bonnaud E. Minimising trapping effort without affecting population density estimations for small mammals. Mamm Biol 2018. [DOI: 10.1016/j.mambio.2018.10.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
31
|
Murphy SM, Augustine BC, Adams JR, Waits LP, Cox JJ. Integrating multiple genetic detection methods to estimate population density of social and territorial carnivores. Ecosphere 2018. [DOI: 10.1002/ecs2.2479] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Sean M. Murphy
- Louisiana Department of Wildlife and Fisheries; Large Carnivore Program; Lafayette Louisiana 70506 USA
| | - Ben C. Augustine
- Department of Fish and Wildlife Conservation; Virginia Polytechnic Institute and State University; Blacksburg Virginia 24061 USA
| | - Jennifer R. Adams
- Laboratory for Ecological, Evolutionary and Conservation Genetics; Department of Fish and Wildlife Sciences; University of Idaho; Moscow Idaho 83844 USA
| | - Lisette P. Waits
- Laboratory for Ecological, Evolutionary and Conservation Genetics; Department of Fish and Wildlife Sciences; University of Idaho; Moscow Idaho 83844 USA
| | - John J. Cox
- Department of Forestry and Natural Resources; University of Kentucky; Lexington Kentucky 40546 USA
| |
Collapse
|
32
|
Gardner B, Sollmann R, Kumar NS, Jathanna D, Karanth KU. State space and movement specification in open population spatial capture-recapture models. Ecol Evol 2018; 8:10336-10344. [PMID: 30397470 PMCID: PMC6206188 DOI: 10.1002/ece3.4509] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 07/19/2018] [Accepted: 07/27/2018] [Indexed: 11/22/2022] Open
Abstract
With continued global changes, such as climate change, biodiversity loss, and habitat fragmentation, the need for assessment of long-term population dynamics and population monitoring of threatened species is growing. One powerful way to estimate population size and dynamics is through capture-recapture methods. Spatial capture (SCR) models for open populations make efficient use of capture-recapture data, while being robust to design changes. Relatively few studies have implemented open SCR models, and to date, very few have explored potential issues in defining these models. We develop a series of simulation studies to examine the effects of the state-space definition and between-primary-period movement models on demographic parameter estimation. We demonstrate the implications on a 10-year camera-trap study of tigers in India. The results of our simulation study show that movement biases survival estimates in open SCR models when little is known about between-primary-period movements of animals. The size of the state-space delineation can also bias the estimates of survival in certain cases.We found that both the state-space definition and the between-primary-period movement specification affected survival estimates in the analysis of the tiger dataset (posterior mean estimates of survival ranged from 0.71 to 0.89). In general, we suggest that open SCR models can provide an efficient and flexible framework for long-term monitoring of populations; however, in many cases, realistic modeling of between-primary-period movements is crucial for unbiased estimates of survival and density.
Collapse
Affiliation(s)
- Beth Gardner
- School of Environmental and Forest SciencesUniversity of WashingtonSeattleWashington
| | - Rahel Sollmann
- Department of Wildlife, Fish, and Conservation BiologyUniversity of California, DavisDavisCalifornia
| | | | | | - K. Ullas Karanth
- Centre for Wildlife StudiesBangaloreKarnatakaIndia
- Wildlife Conservation Society – Global Conservation ProgramBronxNew York
- National Centre for Biological Sciences‐TIFRBangaloreIndia
| |
Collapse
|
33
|
Moeller AK, Lukacs PM, Horne JS. Three novel methods to estimate abundance of unmarked animals using remote cameras. Ecosphere 2018. [DOI: 10.1002/ecs2.2331] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Anna K. Moeller
- Wildlife Biology Program; Department of Ecosystem and Conservation Sciences; W.A. Franke College of Forestry and Conservation; University of Montana; Missoula Montana 59812 USA
| | - Paul M. Lukacs
- Wildlife Biology Program; Department of Ecosystem and Conservation Sciences; W.A. Franke College of Forestry and Conservation; University of Montana; Missoula Montana 59812 USA
| | - Jon S. Horne
- Idaho Department of Fish and Game; Lewiston Idaho 83501 USA
| |
Collapse
|
34
|
Evans MJ, Rittenhouse TAG. Evaluating spatially explicit density estimates of unmarked wildlife detected by remote cameras. J Appl Ecol 2018. [DOI: 10.1111/1365-2664.13194] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Michael J. Evans
- Department of Natural Resources and the EnvironmentWildlife and Fisheries Conservation CenterUniversity of Connecticut Storrs Connecticut
| | - Tracy A. G. Rittenhouse
- Department of Natural Resources and the EnvironmentWildlife and Fisheries Conservation CenterUniversity of Connecticut Storrs Connecticut
| |
Collapse
|
35
|
Kristensen TV, Kovach AI. Spatially explicit abundance estimation of a rare habitat specialist: implications for
SECR
study design. Ecosphere 2018. [DOI: 10.1002/ecs2.2217] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
- Thea V. Kristensen
- Department of Natural Resources and the Environment University of New Hampshire Durham New Hampshire 03824 USA
| | - Adrienne I. Kovach
- Department of Natural Resources and the Environment University of New Hampshire Durham New Hampshire 03824 USA
| |
Collapse
|
36
|
Linden DW, Sirén APK, Pekins PJ. Integrating telemetry data into spatial capture–recapture modifies inferences on multi‐scale resource selection. Ecosphere 2018. [DOI: 10.1002/ecs2.2203] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Daniel W. Linden
- New York Cooperative Fish and Wildlife Research Unit Department of Natural Resources Cornell University Ithaca New York 14853 USA
| | - Alexej P. K. Sirén
- Department of Natural Resources and the Environment University of New Hampshire Durham New Hampshire 03824 USA
| | - Peter J. Pekins
- Department of Natural Resources and the Environment University of New Hampshire Durham New Hampshire 03824 USA
| |
Collapse
|
37
|
Murphy A, Gerber BD, Farris ZJ, Karpanty S, Ratelolahy F, Kelly MJ. Making the most of sparse data to estimate density of a rare and threatened species: a case study with the fosa, a little‐studied Malagasy carnivore. Anim Conserv 2018. [DOI: 10.1111/acv.12420] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- A. Murphy
- Department of Fish and Wildlife Conservation Virginia Tech Blacksburg VA USA
| | - B. D. Gerber
- Department of Natural Resources Science University of Rhode Island Kingston RI USA
| | - Z. J. Farris
- Department of Fish and Wildlife Conservation Virginia Tech Blacksburg VA USA
- Department of Health and Exercise Science Appalachian State University Boone NC USA
| | - S. Karpanty
- Department of Fish and Wildlife Conservation Virginia Tech Blacksburg VA USA
| | - F. Ratelolahy
- Madagascar Program Wildlife Conservation Society Antananarivo Madagascar
| | - M. J. Kelly
- Department of Fish and Wildlife Conservation Virginia Tech Blacksburg VA USA
| |
Collapse
|
38
|
Morin DJ, Waits LP, McNitt DC, Kelly MJ. Efficient single-survey estimation of carnivore density using fecal DNA and spatial capture-recapture: a bobcat case study. POPUL ECOL 2018. [DOI: 10.1007/s10144-018-0606-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
39
|
Gelin ML, Branch LC, Thornton DH, Novaro AJ, Gould MJ, Caragiulo A. Response of pumas (Puma concolor) to migration of their primary prey in Patagonia. PLoS One 2017; 12:e0188877. [PMID: 29211753 PMCID: PMC5718558 DOI: 10.1371/journal.pone.0188877] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 11/14/2017] [Indexed: 11/18/2022] Open
Abstract
Large-scale ungulate migrations result in changes in prey availability for top predators and, as a consequence, can alter predator behavior. Migration may include entire populations of prey species, but often prey populations exhibit partial migration with some individuals remaining resident and others migrating. Interactions of migratory prey and predators have been documented in North America and some other parts of the world, but are poorly studied in South America. We examined the response of pumas (Puma concolor) to seasonal migration of guanacos (Lama guanicoe) in La Payunia Reserve in northern Patagonia Argentina, which is the site of the longest known ungulate migration in South America. More than 15,000 guanacos migrate seasonally in this landscape, and some guanacos also are resident year-round. We hypothesized that pumas would respond to the guanaco migration by consuming more alternative prey rather than migrating with guanacos because of the territoriality of pumas and availability of alternative prey throughout the year at this site. To determine whether pumas moved seasonally with the guanacos, we conducted camera trapping in the summer and winter range of guanacos across both seasons and estimated density of pumas with spatial mark-resight (SMR) models. Also, we analyzed puma scats to assess changes in prey consumption in response to guanaco migration. Density estimates of pumas did not change significantly in the winter and summer range of guanacos when guanacos migrated to and from these areas, indicating that pumas do not follow the migration of guanacos. Pumas also did not consume more alternative native prey or livestock when guanaco availability was lower, but rather fed primarily on guanacos and some alternative prey during all seasons. Alternative prey were most common in the diet during summer when guanacos also were abundant on the summer range. The response of pumas to the migration of guanacos differs from sites in the western North America where entire prey populations migrate and pumas migrate with their prey or switch to more abundant prey when their primary prey migrates.
Collapse
Affiliation(s)
- Maria L. Gelin
- Department of Wildlife Ecology and Conservation, and School of Natural Resources and Environment, University of Florida, Gainesville, Florida, United States of America
| | - Lyn C. Branch
- Department of Wildlife Ecology and Conservation, and School of Natural Resources and Environment, University of Florida, Gainesville, Florida, United States of America
- * E-mail:
| | - Daniel H. Thornton
- School of the Environment, Washington State University, Pullman, Washington, United States of America
| | - Andrés J. Novaro
- Programa Estepa Patagónica y Andina, INIBIOMA-Universidad Nacional del Comahue-CONICET, Wildlife Conservation Society, Junín de los Andes, Neuquén, Argentina
| | - Matthew J. Gould
- Department of Biology, New Mexico State University, Las Cruces, New Mexico, United States of America
| | - Anthony Caragiulo
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, New York, United States of America
| |
Collapse
|
40
|
Tenan S, Pedrini P, Bragalanti N, Groff C, Sutherland C. Data integration for inference about spatial processes: A model-based approach to test and account for data inconsistency. PLoS One 2017; 12:e0185588. [PMID: 28973034 PMCID: PMC5626469 DOI: 10.1371/journal.pone.0185588] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 09/17/2017] [Indexed: 11/18/2022] Open
Abstract
Recently-developed methods that integrate multiple data sources arising from the same ecological processes have typically utilized structured data from well-defined sampling protocols (e.g., capture-recapture and telemetry). Despite this new methodological focus, the value of opportunistic data for improving inference about spatial ecological processes is unclear and, perhaps more importantly, no procedures are available to formally test whether parameter estimates are consistent across data sources and whether they are suitable for integration. Using data collected on the reintroduced brown bear population in the Italian Alps, a population of conservation importance, we combined data from three sources: traditional spatial capture-recapture data, telemetry data, and opportunistic data. We developed a fully integrated spatial capture-recapture (SCR) model that included a model-based test for data consistency to first compare model estimates using different combinations of data, and then, by acknowledging data-type differences, evaluate parameter consistency. We demonstrate that opportunistic data lend itself naturally to integration within the SCR framework and highlight the value of opportunistic data for improving inference about space use and population size. This is particularly relevant in studies of rare or elusive species, where the number of spatial encounters is usually small and where additional observations are of high value. In addition, our results highlight the importance of testing and accounting for inconsistencies in spatial information from structured and unstructured data so as to avoid the risk of spurious or averaged estimates of space use and consequently, of population size. Our work supports the use of a single modeling framework to combine spatially-referenced data while also accounting for parameter consistency.
Collapse
Affiliation(s)
- Simone Tenan
- Vertebrate Zoology Section, MUSE - Museo delle Scienze, Corso del Lavoro e della Scienza 3, 38122 Trento, Italy
- * E-mail:
| | - Paolo Pedrini
- Vertebrate Zoology Section, MUSE - Museo delle Scienze, Corso del Lavoro e della Scienza 3, 38122 Trento, Italy
| | - Natalia Bragalanti
- Vertebrate Zoology Section, MUSE - Museo delle Scienze, Corso del Lavoro e della Scienza 3, 38122 Trento, Italy
- Provincia Autonoma di Trento, Servizio Foreste e Fauna, Via Trener 3, 38100 Trento, Italy
| | - Claudio Groff
- Provincia Autonoma di Trento, Servizio Foreste e Fauna, Via Trener 3, 38100 Trento, Italy
| | - Chris Sutherland
- Department of Environmental Conservation, University of Massachusetts, Amherst, MA, 01003, United States of America
| |
Collapse
|
41
|
Popescu VD, Iosif R, Pop MI, Chiriac S, Bouroș G, Furnas BJ. Integrating sign surveys and telemetry data for estimating brown bear ( Ursus arctos) density in the Romanian Carpathians. Ecol Evol 2017; 7:7134-7144. [PMID: 28944005 PMCID: PMC5606905 DOI: 10.1002/ece3.3177] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 05/07/2017] [Accepted: 05/25/2017] [Indexed: 11/06/2022] Open
Abstract
Accurate population size estimates are important information for sustainable wildlife management. The Romanian Carpathians harbor the largest brown bear (Ursus arctos) population in Europe, yet current management relies on estimates of density that lack statistical oversight and ignore uncertainty deriving from track surveys. In this study, we investigate an alternative approach to estimate brown bear density using sign surveys along transects within a novel integration of occupancy models and home range methods. We performed repeated surveys along 2-km segments of forest roads during three distinct seasons: spring 2011, fall-winter 2011, and spring 2012, within three game management units and a Natura 2000 site. We estimated bears abundances along transects using the number of unique tracks observed per survey occasion via N-mixture hierarchical models, which account for imperfect detection. To obtain brown bear densities, we combined these abundances with the effective sampling area of the transects, that is, estimated as a function of the median (± bootstrapped SE) of the core home range (5.58 ± 1.08 km2) based on telemetry data from 17 bears tracked for 1-month periods overlapping our surveys windows. Our analyses yielded average brown bear densities (and 95% confidence intervals) for the three seasons of: 11.5 (7.8-15.3), 11.3 (7.4-15.2), and 12.4 (8.6-16.3) individuals/100 km2. Across game management units, mean densities ranged between 7.5 and 14.8 individuals/100 km2. Our method incorporates multiple sources of uncertainty (e.g., effective sampling area, imperfect detection) to estimate brown bear density, but the inference fundamentally relies on unmarked individuals only. While useful as a temporary approach to monitor brown bears, we urge implementing DNA capture-recapture methods regionally to inform brown bear management and recommend increasing resources for GPS collars to improve estimates of effective sampling area.
Collapse
Affiliation(s)
- Viorel D Popescu
- Department of Biological Sciences Ohio University Athens OH USA.,Centre for Environmental Research (CCMESI) University of Bucharest Bucharest Romania
| | - Ruben Iosif
- Centre for Environmental Research (CCMESI) University of Bucharest Bucharest Romania
| | - Mihai I Pop
- Centre for Environmental Research (CCMESI) University of Bucharest Bucharest Romania.,Asociatia pentru Conservarea Diversitatii Biologice (ACDB) Focsani Romania
| | | | - George Bouroș
- Asociatia pentru Conservarea Diversitatii Biologice (ACDB) Focsani Romania
| | - Brett J Furnas
- California Department of Fish and Wildlife Wildlife Investigations Laboratory Rancho Cordova CA USA.,Department of Environmental Science, Policy and Management University of California Berkeley CA USA
| |
Collapse
|
42
|
Efford MG, Hunter CM. Spatial capture-mark-resight estimation of animal population density. Biometrics 2017; 74:411-420. [DOI: 10.1111/biom.12766] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Revised: 07/01/2017] [Accepted: 07/01/2017] [Indexed: 11/28/2022]
Affiliation(s)
- Murray G. Efford
- Department of Mathematics and Statistics; University of Otago; P.O. Box 56, Dunedin New Zealand
| | | |
Collapse
|
43
|
Whittington J, Hebblewhite M, Chandler RB. Generalized spatial mark-resight models with an application to grizzly bears. J Appl Ecol 2017. [DOI: 10.1111/1365-2664.12954] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jesse Whittington
- Parks Canada; Banff National Park Resource Conservation; Banff AB Canada
| | - Mark Hebblewhite
- Wildlife Biology Program; Department of Ecosystem and Conservation Sciences; College of Forestry and Conservation; University of Montana; Missoula MT USA
| | - Richard B. Chandler
- Warnell School of Forestry and Natural Resources; University of Georgia; Athens GA USA
| |
Collapse
|
44
|
Canu A, Mattioli L, Santini A, Apollonio M, Scandura M. ‘Video-scats’: combining camera trapping and non-invasive genotyping to assess individual identity and hybrid status in gray wolf. WILDLIFE BIOLOGY 2017. [DOI: 10.2981/wlb.00355] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Antonio Canu
- A. Canu, M. Apollonio and M. Scandura , Dept. of Science for Nature and Environmental Resources, Univ. of Sassari, Via Muroni 25, IT-07100 Sassari, Italy. AC also at: C.I.R.Se.M.A.F. Firenze, Italy
| | - Luca Mattioli
- L. Mattioli, Regione Toscana, Settore Attività Faunistico Venatoria, Pesca Dilettantistica, Pesca in Mare, Arezzo, Italy
| | | | - Marco Apollonio
- A. Canu, M. Apollonio and M. Scandura , Dept. of Science for Nature and Environmental Resources, Univ. of Sassari, Via Muroni 25, IT-07100 Sassari, Italy. AC also at: C.I.R.Se.M.A.F. Firenze, Italy
| | - Massimo Scandura
- A. Canu, M. Apollonio and M. Scandura , Dept. of Science for Nature and Environmental Resources, Univ. of Sassari, Via Muroni 25, IT-07100 Sassari, Italy. AC also at: C.I.R.Se.M.A.F. Firenze, Italy
| |
Collapse
|
45
|
Estimating abundance of striped hyenas (Hyaena hyaena) in the Negev Desert of Israel using camera traps and closed capture–recapture models. EUR J WILDLIFE RES 2016. [DOI: 10.1007/s10344-016-1069-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
46
|
Beausoleil RA, Clark JD, Maletzke BT. A long-term evaluation of biopsy darts and DNA to estimate cougar density: An agency-citizen science collaboration. WILDLIFE SOC B 2016. [DOI: 10.1002/wsb.675] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Richard A. Beausoleil
- Washington Department of Fish and Wildlife; 3515 State Highway 97A Wenatchee WA 98801 USA
| | - Joseph D. Clark
- United States Geological Survey, Southern Appalachian Field Branch; University of Tennessee; Knoxville TN 37902 USA
| | - Benjamin T. Maletzke
- Washington Department of Fish and Wildlife; P.O. Box 238 South Cle Elum WA 98943 USA
| |
Collapse
|
47
|
|
48
|
Morin DJ, Kelly MJ, Waits LP. Monitoring coyote population dynamics with fecal DNA and spatial capture-recapture. J Wildl Manage 2016. [DOI: 10.1002/jwmg.21080] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Dana J. Morin
- Department of Fish and Wildlife Conservation; Virginia Tech; 106 Cheatham Hall Blacksburg VA 24061 USA
| | - Marcella J. Kelly
- Department of Fish and Wildlife Conservation; Virginia Tech; 106 Cheatham Hall Blacksburg VA 24061 USA
| | - Lisette P. Waits
- Department of Fish and Wildlife Sciences; University of Idaho; 875 Perimeter Drive Moscow ID 83844-1136 USA
| |
Collapse
|
49
|
Identification and Density Estimation of American Martens (Martes americana) Using a Novel Camera-Trap Method. DIVERSITY-BASEL 2016. [DOI: 10.3390/d8010003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
50
|
Schmidt JH, Johnson DS, Lindberg MS, Adams LG. Estimating demographic parameters using a combination of known-fate and open N-mixture models. Ecology 2016; 96:2583-9. [PMID: 26649379 DOI: 10.1890/15-0385.1] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Accurate estimates of demographic parameters are required to infer appropriate ecological relationships and inform management actions. Known-fate data from marked individuals are commonly used to estimate survival rates, whereas N-mixture models use count data from unmarked individuals to estimate multiple demographic parameters. However, a joint approach combining the strengths of both analytical tools has not been developed. Here we develop an integrated model combining known-fate and open N-mixture models, allowing the estimation of detection probability, recruitment, and the joint estimation of survival. We demonstrate our approach through both simulations and an applied example using four years of known-fate and pack count data for wolves (Canis lupus). Simulation results indicated that the integrated model reliably recovered parameters with no evidence of bias, and survival estimates were more precise under the joint model. Results from the applied example indicated that the marked sample of wolves was biased toward individuals with higher apparent survival rates than the unmarked pack mates, suggesting that joint estimates may be more representative of the overall population. Our integrated model is a practical approach for reducing bias while increasing precision and the amount of information gained from mark-resight data sets. We provide implementations in both the BUGS language and an R package.
Collapse
|