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Delisle ZJ, McGovern PG, Dillman BG, Reeling CJ, Caudell JN, Swihart RK. Using cost‐effectiveness analysis to compare density‐estimation methods for large‐scale wildlife management. WILDLIFE SOC B 2023. [DOI: 10.1002/wsb.1430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Affiliation(s)
- Zackary J. Delisle
- Department of Forestry and Natural Resources Purdue University 195 Marsteller Street West Lafayette IN 47907 USA
| | - Patrick G. McGovern
- Department of Forestry and Natural Resources Purdue University 195 Marsteller Street West Lafayette IN 47907 USA
| | - Brian G. Dillman
- Department of Aviation Technology Purdue University West Lafayette IN 47907 USA
| | - Carson J. Reeling
- Department of Agricultural Economics Purdue University West Lafayette IN 47907 USA
| | - Joe N. Caudell
- Indiana Department of Natural Resources Bloomington IN 47401 USA
| | - Robert K. Swihart
- Department of Forestry and Natural Resources Purdue University 195 Marsteller Street West Lafayette IN 47907 USA
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2
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Wessling EG, Surbeck M. Failure to account for behavioral variability significantly compromises accuracy in indirect population monitoring. Anim Conserv 2022. [DOI: 10.1111/acv.12844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- E. G. Wessling
- Department of Human Evolutionary Biology Harvard University Cambridge MA USA
- School of Psychology and Neuroscience University of St Andrews St Andrews UK
| | - M. Surbeck
- Department of Human Evolutionary Biology Harvard University Cambridge MA USA
- Max Planck Institute for Evolutionary Anthropology Leipzig Germany
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3
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Meier AC, Shirley MH, Beirne C, Breuer T, Lewis M, Masseloux J, Jasperse‐Sjolander L, Todd A, Poulsen JR. Improving population estimates of difficult‐to‐observe species: A dung decay model for forest elephants with remotely sensed imagery. Anim Conserv 2021. [DOI: 10.1111/acv.12704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- A. C. Meier
- Nicholas School of the Environment Duke University Durham NC USA
| | - M. H. Shirley
- Institute of Environment Florida International University North Miami FL USA
| | - C. Beirne
- Nicholas School of the Environment Duke University Durham NC USA
| | - T. Breuer
- World Wide Fund for Nature Germany Berlin Germany
| | - M. Lewis
- Nicholas School of the Environment Duke University Durham NC USA
| | - J. Masseloux
- Nicholas School of the Environment Duke University Durham NC USA
| | | | - A. Todd
- Fauna and Flora International Cambridge United Kingdom
| | - J. R. Poulsen
- Nicholas School of the Environment Duke University Durham NC USA
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Sinayitutse E, Modry D, Slapeta J, Nyiramana A, Mudakikwa A, Muvunyi R, Eckardt W. Daily defecation outputs of mountain gorillas (Gorilla beringei beringei) in the Volcanoes National Park, Rwanda. Primates 2020; 62:311-320. [PMID: 33221967 DOI: 10.1007/s10329-020-00874-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Accepted: 11/02/2020] [Indexed: 02/04/2023]
Abstract
Increasing population density can increase infectious disease risk and thus reduce population growth and size. Host-parasite interactions of threatened animals that remain in small protected forest fragments therefore need to be monitored carefully. Due to extreme conservation efforts, the mountain gorilla (Gorilla beringei beringei) population in the 450-km2 Virunga Massif has more than doubled since 1973, reaching 604 individuals in 2016. To better understand changes in the transmission risks of soil-borne and other enteric pathogens for mountain gorillas, we determined defecation outputs of different age-sex classes and the diurnal variation in feces deposition. We weighed 399 wet fecal samples deposited at nest sites and on trails between nest sites by gorillas of varying age and sex, determined by lobe diameter, from five social groups (n = 58 gorillas) that range in the Volcanoes National Park, Rwanda. We found increasing daily average defecation outputs with increasing age-sex class (infants, 435 g; juveniles, 1346 g; medium-sized gorillas, 2446 g; silverbacks, 3609 g). Gorillas deposited two- to threefold the amount of feces at nest sites compared to on trails, suggesting that nest sites may function as hotspots for enteric pathogen infections through direct contact or when gorillas ingest foods contaminated with infectious larvae during site revisits in intervals matching the maturation period of environmentally transmitted gastrointestinal parasites. In combination with ranging and demographic data, these findings will enable the modeling of spatiotemporal variation in soil contamination and infectious disease risk for Virunga gorillas as their population density continues to increase.
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Affiliation(s)
- Elie Sinayitutse
- The Dian Fossey Gorilla Fund International, 800 Cherokee Ave SE, Atlanta, GA, 30315, USA.
- The University of Rwanda, Butare, Huye, Rwanda.
| | - David Modry
- Department of Pathology and Parasitology, University of Veterinary and Pharmaceutical Sciences, Palackéhotřida 1946/1, 612 42, Brno, Czech Republic
- University of Veterinary and Pharmaceutical Sciences Brno, Palackéhotřida 1946/1, 612 42, Brno, Czech Republic
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, Branišovská 1160/31, 370, České Budějovice, Czech Republic
| | - Jan Slapeta
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Sydney, NSW, 2006, Australia
| | | | - Antoine Mudakikwa
- Department of Tourism and Conservation, Rwanda Development Board, Kigali, Rwanda
| | - Richard Muvunyi
- Department of Tourism and Conservation, Rwanda Development Board, Kigali, Rwanda
| | - Winnie Eckardt
- The Dian Fossey Gorilla Fund International, 800 Cherokee Ave SE, Atlanta, GA, 30315, USA
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Elenga G, Bonenfant C, Péron G. Distance sampling of duikers in the rainforest: Dealing with transect avoidance. PLoS One 2020; 15:e0240049. [PMID: 33031377 PMCID: PMC7544111 DOI: 10.1371/journal.pone.0240049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 09/17/2020] [Indexed: 11/27/2022] Open
Abstract
Bushmeat is a major source of protein and income in tropical regions but is often over-harvested. A better monitoring of bushmeat stocks could help achieve sustainability. We used a combination of simulations and transect survey data collected from blue duikers (Philantomba monticola) in the Lomako wildlife reserve, Democratic Republic of the Congo, to investigate the use of transect-based distance sampling to monitor bushmeat stocks. The comparison of dung piles and direct observations of duikers evidenced that animals avoided both the transects in the absence of observers, and the observers themselves. This type of behavioural response appeared common in a literature survey. It causes a negative bias in the estimates of population densities from the standard distance sampling methodology. This negative bias would lead to over-pessimistic predictions of population viability, especially if the behavioural response is more intense in the locations where the animals are hunted. In turn, this would lead to excessively conservative management recommendations. To correct for the effect of the behavioural response of the animals to either the transects or the observers, we recommend recording both the forward and perpendicular distances to the observers (2D distance sampling), not just the perpendicular distance. We also recommend multiple-observer protocols. As a cautionary note, we also demonstrate a scenario where the intensity of the behavioural response is too high to reliably estimate the abundance of the population. As a perspective, we outline the general principles of a local stakeholder-based program combining distance sampling with less intensive types of ecological indicators to monitor wildlife populations.
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Affiliation(s)
- Gaïus Elenga
- Laboratoire de Biométrie et Biologie Évolutive UMR5558, Univ Lyon, Université Lyon 1, CNRS, Villeurbanne, France
- Department of the Environment, Faculty of Sciences, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Christophe Bonenfant
- Laboratoire de Biométrie et Biologie Évolutive UMR5558, Univ Lyon, Université Lyon 1, CNRS, Villeurbanne, France
| | - Guillaume Péron
- Laboratoire de Biométrie et Biologie Évolutive UMR5558, Univ Lyon, Université Lyon 1, CNRS, Villeurbanne, France
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Adams PJ, Fontaine JB, Huston RM, Fleming PA. Quantifying efficacy of feral pig (Sus scrofa) population management. WILDLIFE RESEARCH 2019. [DOI: 10.1071/wr18100] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Abstract
ContextFeral pigs (Sus scrofa) are an increasing threat to agriculture and ecological communities globally. Although ground rooting is their most readily observable sign, feral pigs typically remain highly cryptic and their abundance and impacts are difficult to quantify.
AimsThe aim of the present study was to evaluate the effect of current feral pig population management practices (trapping, baiting, no feral pig management) on feral pig abundance and digging impacts, using a BACI (before–after control–impact) experimental design at a landscape scale.
MethodsA monitoring program was established to quantify both the abundance and digging impacts of feral pig populations within a temperate sclerophyll forest landscape using distance sampling. Transects were established across eight drinking water catchments where the whole catchment was the unit of replication for feral pig population management. Monitoring was carried out at 6-monthly intervals for 3 years, with no feral pig population management undertaken in the first year. In total, 367 feral pigs were trapped out of three catchments subject to trapping, and 26 were baited across two catchments subject to baiting with a commercial product (PIGOUT, Animal Control Technologies Australia, Melbourne, Vic., Australia). Three catchments were exempt from feral pig population management for the duration of this study.
Key resultsFeral pig density within the overall study site was estimated as 1.127pigskm–2, resulting in 4580diggingskm–2year–1. There was no significant difference in feral pig density estimates observed among population management treatments or the treatment×year interaction term. An overall decrease in feral pig density across all catchments was attributed to extreme temperature and drought conditions experienced during the study.
ConclusionsFeral pig populations demonstrate high resilience to current feral pig population management practices in the present study. The annual volume of soil disturbed by the numbers of feral pigs estimated across this study area is comparable to a commercial-scale resource extraction industry. We did not find significant differences in feral pig digging density among dominant vegetation types, but larger digs were associated with swamp vegetation.
ImplicationsCurrent levels of feral pig population management did not reduce pig densities across eight catchments in the northern jarrah forest; therefore, more intensive population management is needed.
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Ahrestani FS, Kumar NS, Vaidyanathan S, Hiby L, Jathanna D, Karanth KU. Estimating densities of large herbivores in tropical forests: Rigorous evaluation of a dung-based method. Ecol Evol 2018; 8:7312-7322. [PMID: 30151151 PMCID: PMC6106164 DOI: 10.1002/ece3.4227] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 04/09/2018] [Accepted: 04/22/2018] [Indexed: 11/08/2022] Open
Abstract
When sighting-based surveys to estimate population densities of large herbivores in tropical dense forests are not practical or affordable, surveys that rely on animal dung are sometimes used. This study tested one such dung-based method by deriving population densities from observed dung densities of six large herbivores (chital, elephant, gaur, muntjac, sambar, and wild pig) in two habitats, dry deciduous forests (DDF) and moist deciduous forests (MDF), within Nagarahole National Park, southern India. Using the program DUNGSURV, dung pile counts, decay rates estimated from field experiments, and defecation rates derived from literature were analyzed together by a model that allows for random events affecting dung decay. Densities of chital were the highest, followed by sambar. Wild pig densities were similar in the two habitats, sambar densities were higher in DDF, and densities of the other species were higher in MDF than in DDF. We compared DUNGSURV estimates with densities estimated using distance sampling in the same season. DUNGSURV estimates were substantially higher for all species in both habitats. These differences highlight the challenges that researchers face in computing unbiased estimates of dung decay rates and in relying on defecation rates from literature. Besides the elephant, this study is the first to rigorously test the efficacy of using a dung-based approach to estimate densities of large herbivore species in Asia, and based on this evaluation, we provide specific recommendations to address issues that require careful consideration before observed dung densities are used to derive animal densities. Our results underline the need for an experimental study of a known population in a fenced reserve to validate the true potential of using dung-based approaches to estimate population densities.
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Affiliation(s)
| | - N. Samba Kumar
- India ProgramWildlife Conservation SocietyBengaluruIndia
| | | | - Lex Hiby
- Conservation Research Ltd.CambridgeUK
| | | | - K. Ullas Karanth
- India ProgramWildlife Conservation SocietyBengaluruIndia
- Centre for Wildlife StudiesBengaluruIndia
- Wildlife Conservation SocietyGlobal Conservation ProgramBronxNew York
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Arandjelovic M, Vigilant L. Non-invasive genetic censusing and monitoring of primate populations. Am J Primatol 2018; 80:e22743. [PMID: 29457631 DOI: 10.1002/ajp.22743] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 12/16/2017] [Accepted: 01/14/2018] [Indexed: 02/06/2023]
Abstract
Knowing the density or abundance of primate populations is essential for their conservation management and contextualizing socio-demographic and behavioral observations. When direct counts of animals are not possible, genetic analysis of non-invasive samples collected from wildlife populations allows estimates of population size with higher accuracy and precision than is possible using indirect signs. Furthermore, in contrast to traditional indirect survey methods, prolonged or periodic genetic sampling across months or years enables inference of group membership, movement, dynamics, and some kin relationships. Data may also be used to estimate sex ratios, sex differences in dispersal distances, and detect gene flow among locations. Recent advances in capture-recapture models have further improved the precision of population estimates derived from non-invasive samples. Simulations using these methods have shown that the confidence interval of point estimates includes the true population size when assumptions of the models are met, and therefore this range of population size minima and maxima should be emphasized in population monitoring studies. Innovations such as the use of sniffer dogs or anti-poaching patrols for sample collection are important to ensure adequate sampling, and the expected development of efficient and cost-effective genotyping by sequencing methods for DNAs derived from non-invasive samples will automate and speed analyses.
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Affiliation(s)
- Mimi Arandjelovic
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Linda Vigilant
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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Phillips CA, Woolley C, Mann D, McGrew WC. Disappearance rate of chimpanzee scats: Implications for census work onPan troglodytes. Afr J Ecol 2018. [DOI: 10.1111/aje.12501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Caroline A. Phillips
- Department of Archaeology and Anthropology; University of Cambridge; Cambridge England
- Evolutionary Studies Institute; University of the Witwatersrand; Johannesburg South Africa
| | - Christopher Woolley
- Evolutionary Studies Institute; University of the Witwatersrand; Johannesburg South Africa
| | - Darren Mann
- Oxford University Museum of Natural History; Oxford England
| | - William C. McGrew
- School of Psychology & Neuroscience; University of St. Andrews; St. Andrews Scotland
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Haurez B, Tagg N, Petre CA, Brostaux Y, Boubady A, Doucet JL. Seed dispersal effectiveness of the western lowland gorilla (Gorilla gorilla gorilla
) in Gabon. Afr J Ecol 2017. [DOI: 10.1111/aje.12449] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Barbara Haurez
- TERRA Teaching and Research Center; Central African Forests; Gembloux Agro-Bio Tech; University of Liège; Gembloux Belgium
- Nature Plus NPO; Wavre Belgium
- École Régionale Post-Universitaire d'Aménagement et de Gestion Intégrés des Forêts et Territoires Tropicaux (ERAIFT); Kinshasa Democratic Republic of Congo
| | - Nikki Tagg
- Projet Grands Singes (PGS); Antwerp Zoo Centre for Research and Conservation; Royal Zoological Society of Antwerp (RZSA); Antwerpen Belgium
| | - Charles-Albert Petre
- TERRA Teaching and Research Center; Central African Forests; Gembloux Agro-Bio Tech; University of Liège; Gembloux Belgium
- Projet Grands Singes (PGS); Antwerp Zoo Centre for Research and Conservation; Royal Zoological Society of Antwerp (RZSA); Antwerpen Belgium
- Conservation Biology Unit; Directorate Natural Environment; Royal Belgian Institute of Natural Sciences; Brussels Belgium
| | - Yves Brostaux
- TERRA Teaching and Research Center; Central African Forests; Gembloux Agro-Bio Tech; University of Liège; Gembloux Belgium
| | - Armand Boubady
- Institut de recherche en écologie tropicale; Cenarest; Libreville Gabon
| | - Jean-Louis Doucet
- TERRA Teaching and Research Center; Central African Forests; Gembloux Agro-Bio Tech; University of Liège; Gembloux Belgium
- École Régionale Post-Universitaire d'Aménagement et de Gestion Intégrés des Forêts et Territoires Tropicaux (ERAIFT); Kinshasa Democratic Republic of Congo
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11
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Howe EJ, Buckland ST, Després‐Einspenner M, Kühl HS. Distance sampling with camera traps. Methods Ecol Evol 2017. [DOI: 10.1111/2041-210x.12790] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Eric J. Howe
- Centre for Research into Ecological and Environmental Modelling University of St Andrews The Observatory, Buchanan Gardens St Andrews Fife KY16 9LZ UK
| | - Stephen T. Buckland
- Centre for Research into Ecological and Environmental Modelling University of St Andrews The Observatory, Buchanan Gardens St Andrews Fife KY16 9LZ UK
| | | | - Hjalmar S. Kühl
- Max Planck Institute for Evolutionary Anthropology Deutscher Platz 6 04103 Leipzig Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle‐Jena‐Leipzig Deutscher Platz 5e 04103 Leipzig Germany
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12
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Phillips CA, Wrangham RW, McGrew WC. Non-dietary analytical features of chimpanzee scats. Primates 2017; 58:393-402. [PMID: 28378197 DOI: 10.1007/s10329-017-0606-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Accepted: 03/28/2017] [Indexed: 12/01/2022]
Abstract
Non-dietary aspects of ape scats such as scat weight and diameter are correlated with age and sex of defaecator for gorillas and orangutans. Defaecation rates of primates, including apes, illuminate their role as primary seed dispersers. We assess if non-dietary features of scats for East African chimpanzees (Pan troglodytes schweinfurthii) reveal such insights for members of the Kanyawara community in Kibale National Park, Uganda. Our objective is to see if such data yield useful perspectives for future census work on unhabituated chimpanzees, that is, what can scats tell us about a wild study population, beyond diet? We followed ten adults from this community, as well as travelling parties, comparing observed vs. unobserved defaecations, and collected data on scat weight and dimensions, defaecation rate, scat encounter rate, and interval between defaecations. Few non-dietary features of chimpanzee scats significantly differentiated sex or age of the defaecator, but total scat length and height distinguished adults from juveniles/infants. Defaecation rates and distance travelled were similar for adult males and females, indicating the importance of both sexes as potential primary seed dispersers. Observed travelling parties vs. non-observed travelling parties yielded similar data, indicating the potential to assess party size from scat encounter rates over a set distance. We provide detailed measurements of scat dimensions for this ape taxon which previously have been lacking. This research builds upon prior work by recording more in-depth data for focal subjects and travelling parties on defaecation and scat encounter rates. The findings presented should assist in the interpretation of scat data when censusing unhabituated chimpanzees.
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Affiliation(s)
- Caroline A Phillips
- Evolutionary Studies Institute, University of the Witwatersrand, Private Bag 3, Wits, 2050, South Africa. .,Department of Archaeology and Anthropology, University of Cambridge, 13A Fitzwilliam Street, Cambridge, CB2 1QH, UK.
| | - Richard W Wrangham
- Department of Human Evolutionary Biology, Peabody Museum, Harvard University, 11 Divinity Avenue, Cambridge, MA, 02138, USA
| | - William C McGrew
- Department of Archaeology and Anthropology, University of Cambridge, 13A Fitzwilliam Street, Cambridge, CB2 1QH, UK.,School of Psychology and Neuroscience, University of St. Andrews, St. Andrews, KY16 9JU, UK
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Crunchant AS, Egerer M, Loos A, Burghardt T, Zuberbühler K, Corogenes K, Leinert V, Kulik L, Kühl HS. Automated face detection for occurrence and occupancy estimation in chimpanzees. Am J Primatol 2017; 79:1-12. [PMID: 28095593 DOI: 10.1002/ajp.22627] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 10/28/2016] [Accepted: 11/16/2016] [Indexed: 11/07/2022]
Abstract
Surveying endangered species is necessary to evaluate conservation effectiveness. Camera trapping and biometric computer vision are recent technological advances. They have impacted on the methods applicable to field surveys and these methods have gained significant momentum over the last decade. Yet, most researchers inspect footage manually and few studies have used automated semantic processing of video trap data from the field. The particular aim of this study is to evaluate methods that incorporate automated face detection technology as an aid to estimate site use of two chimpanzee communities based on camera trapping. As a comparative baseline we employ traditional manual inspection of footage. Our analysis focuses specifically on the basic parameter of occurrence where we assess the performance and practical value of chimpanzee face detection software. We found that the semi-automated data processing required only 2-4% of the time compared to the purely manual analysis. This is a non-negligible increase in efficiency that is critical when assessing the feasibility of camera trap occupancy surveys. Our evaluations suggest that our methodology estimates the proportion of sites used relatively reliably. Chimpanzees are mostly detected when they are present and when videos are filmed in high-resolution: the highest recall rate was 77%, for a false alarm rate of 2.8% for videos containing only chimpanzee frontal face views. Certainly, our study is only a first step for transferring face detection software from the lab into field application. Our results are promising and indicate that the current limitation of detecting chimpanzees in camera trap footage due to lack of suitable face views can be easily overcome on the level of field data collection, that is, by the combined placement of multiple high-resolution cameras facing reverse directions. This will enable to routinely conduct chimpanzee occupancy surveys based on camera trapping and semi-automated processing of footage. RESEARCH HIGHLIGHTS Using semi-automated ape face detection technology for processing camera trap footage requires only 2-4% of the time compared to manual analysis and allows to estimate site use by chimpanzees relatively reliably.
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Affiliation(s)
| | - Monika Egerer
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Alexander Loos
- Fraunhofer Institute for Digital Media Technology IDMT, Ilmenau, Germany
| | - Tilo Burghardt
- Department of Computer Science, University of Bristol, Bristol, UK
| | - Klaus Zuberbühler
- Department of Comparative Cognition, University of Neuchâtel, Neuchâtel, Switzerland.,School of Psychology and Neuroscience, University of St Andrews, St Andrews, Scotland.,Budongo Conservation Field Station, Masindi, Uganda
| | | | - Vera Leinert
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Lars Kulik
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Hjalmar S Kühl
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Leipzig-Jena, Leipzig, Germany
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14
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Jost Robinson CA, Zollner PA, Kpanou JB. Night and day: evaluating transect methodologies to monitor duikers in the Dzanga-Sangha Protected Areas, Central African Republic. Afr J Ecol 2016. [DOI: 10.1111/aje.12344] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Carolyn A Jost Robinson
- Department of Anthropology; University of North Carolina, Wilmington; 601 S. College Rd. Wilmington NC 28403 U.S.A
| | - Patrick A Zollner
- Department of Forestry and Natural Resources; Purdue University; 715 West State Street West Lafayette IN 47907 U.S.A
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The role of great apes in seed dispersal of the tropical forest tree species Dacryodes normandii (Burseraceae) in Gabon. JOURNAL OF TROPICAL ECOLOGY 2015. [DOI: 10.1017/s0266467415000322] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Abstract:The identification of seed dispersers and predators is essential to understand the effect of anthropogenic disturbances, and the associated defaunation process, on tropical forest dynamics in Central Africa. In this study, the animals involved in seed predation and dispersal of Dacryodes normandii (Burseraceae), an endozoochorously dispersed tree species endemic to Gabonese forests, were identified in a site in south-east Gabon using two complementary methods: direct observation and camera-trap monitoring of fruit piles. The combined sampling effort (172 h of direct observations and 796 d of camera trapping) led to the identification of six disperser and eight predator species of D. normandii seeds. With high frequency of consumption (88% and 57% of their visits, respectively) and long visit duration (83 and 23 min, respectively), the western lowland gorilla and central chimpanzee were identified as the main dispersers of this species. Seeds passed through the gorilla gut exhibited high germination success (68%). Rodents were identified as predators of D. normandii seeds, potentially displaying rare secondary dispersal through scatter-hoarding. The results of this study highlight the importance of great apes in the seed dispersal of this tree species.
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16
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Quantity and spatial distribution of seeds dispersed by a western lowland gorilla population in south-east Cameroon. JOURNAL OF TROPICAL ECOLOGY 2015. [DOI: 10.1017/s0266467415000073] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Abstract:Understanding the ecological function of large frugivores in tropical forests is important considering their central position in seed-dispersal networks. This study illustrates the seed-dispersal effectiveness of a western lowland gorilla (Gorilla gorilla gorilla) population in Cameroon by looking at the interaction of seed quantity, species regeneration traits and the environmental characteristics of the deposition sites (sleeping sites vs. feeding trails) in order to discuss the role of gorillas within the ecosystem. The analysis of 1030 faecal samples collected over a 3-y period (September 2009–August 2012) showed that gorillas dispersed a diverse array of species (58 spp. identified), with an average of 289 intact seeds (>5 mm) d−1 per individual. Seed damage during mouth and gut processing occurred for 12 spp., generally accounting for <5% of specific seed load. Germination trials suggested that germination success of passed seeds remained unchanged (N = 6 spp.) or improved (N = 5 spp.) after gut passage compared with hand-cleaned seeds, with one exception. Indicator species identification (IndVal method) and General Discriminant Analysis suggested that sleeping sites (N = 36), as a main type of seed deposition site, correspond to regenerating microhabitats and correspondingly degree of canopy openness is one variable discriminating significantly this type of deposition site with random locations in the forest (N = 36) used as a proxy for non-directed seed deposition on feeding trails. With a mean canopy openness of 19–27%, sleeping sites offer optimal light conditions for the seedling recruitment of non-pioneer light-demanding species, the seeds of which encompass 47.4% of the total seed load dispersed over the 3-y period. From this study, it is hypothesized that the gorilla performed directed-dispersal of some light-demanding plant species at sleeping sites, and hence, by being actively implicated in gap-phase dynamics, fulfils a valuable ecological function within its ecosystem.
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Differences in dung beetle activity at western gorilla defecation sites in south-east Cameroon: implications for establishment of Uapaca spp. seedlings. JOURNAL OF TROPICAL ECOLOGY 2015. [DOI: 10.1017/s0266467414000753] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Abstract:For endozoochorous seed dispersal systems, the extant dung beetle assemblage at seed deposition sites may influence site suitability as burial activity may change the probability that seeds germinate and seedlings establish. This study tested if the different conditions of the two main seed-deposition habitats of a western lowland gorilla population of south-east Cameroon (sleeping sites and old secondary forest) influenced dung beetle assemblages and consequently the seed relocation patterns. In March 2012, in both habitats, burial patterns (proportion and depth) were described in eight stations based on two 300-g experimental faeces with known number of Uapaca spp. seeds (N = 75) left for 48 h, and beetle assemblages were described based on one 48h-dung-baited pitfall trapping session in five of these stations. To assess the impact of burial pattern on seedling emergence, Uapaca seedling emergence trials were performed in a nursery (75 seeds per depth treatment). Assemblage at sleeping sites had a higher species richness (non-significant) and was significantly more abundant than in old secondary forests. Conversely, significantly more seeds were buried in old secondary forests than sleeping sites and at significantly greater depths (mean: 14.9 cm vs. 8.7 cm). As trials suggested that burial depth ≥7 cm prevented Uapaca seedling emergence, dung beetles are assumed to induce seed loss more strongly in old secondary forests than sleeping sites (20.5% vs. 6.7% of initial seed crop). The demonstration that dung beetles may exert a negative influence on seed fate overall, and that the degree to which this occurs may vary depending on habitat, highlights the complexity in determining the suitability of deposition sites for recruitment.
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The Influence of Transect Use by Local People and Reuse of Transects for Repeated Surveys on Nesting in Western Lowland Gorillas (Gorilla gorilla gorilla) and Central Chimpanzees (Pan troglodytes troglodytes) in Southeast Cameroon. INT J PRIMATOL 2013. [DOI: 10.1007/s10764-013-9681-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Morton FB, Todd AF, Lee P, Masi S. Observational Monitoring of Clinical Signs during the Last Stage of Habituation in a Wild Western Gorilla Group at Bai Hokou, Central African Republic. Folia Primatol (Basel) 2013; 84:118-33. [DOI: 10.1159/000350916] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 03/21/2013] [Indexed: 11/19/2022]
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Bengsen AJ, Leung LKP, Lapidge SJ, Gordon IJ. Using a general index approach to analyze camera-trap abundance indices. J Wildl Manage 2011. [DOI: 10.1002/jwmg.132] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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