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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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Breaking Dawn: factors influencing mammalian habitat usage in western Assam following socio-political instability. J Nat Conserv 2023. [DOI: 10.1016/j.jnc.2023.126357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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3
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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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4
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Delisle ZJ, Swihart RK, Quinby BM, Sample RD, Kinser‐Mcbee KJ, Tauber EK, Flaherty EA. Density from pellet groups: Comparing methods for estimating dung persistence time. WILDLIFE SOC B 2022. [DOI: 10.1002/wsb.1325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Zackary J. Delisle
- Purdue University Department of Forestry and Natural Resources 195 Marsteller Street West Lafayette IN 47907 USA
| | - Robert K. Swihart
- Purdue University Department of Forestry and Natural Resources 195 Marsteller Street West Lafayette IN 47907 USA
| | - Brandon M. Quinby
- Purdue University Department of Forestry and Natural Resources 195 Marsteller Street West Lafayette IN 47907 USA
| | - Richard D. Sample
- Purdue University Department of Forestry and Natural Resources 195 Marsteller Street West Lafayette IN 47907 USA
| | - Kevin J. Kinser‐Mcbee
- Purdue University Department of Forestry and Natural Resources 195 Marsteller Street West Lafayette IN 47907 USA
| | - Emily K. Tauber
- Purdue University Department of Forestry and Natural Resources 195 Marsteller Street West Lafayette IN 47907 USA
| | - Elizabeth A. Flaherty
- Purdue University Department of Forestry and Natural Resources 195 Marsteller Street West Lafayette IN 47907 USA
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Laverty TM, Berger J. Indirect effects of African megaherbivore conservation on bat diversity in the world's oldest desert. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2022; 36:e13780. [PMID: 34061400 DOI: 10.1111/cobi.13780] [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: 12/14/2020] [Revised: 05/22/2021] [Accepted: 05/24/2021] [Indexed: 06/12/2023]
Abstract
In extreme environments, temperature and precipitation are often the main forces responsible for structuring ecological communities and species distributions. The role of biotic interactions is typically thought to be minimal. By clustering around rare and isolated features, like surface water, however, effects of herbivory by desert-dwelling wildlife can be amplified. Understanding how species interact in these environments is critical to safeguarding vulnerable or data-deficient species. We examined whether African elephants (Loxodonta africana), black rhinoceros (Diceros bicornis), and southern giraffe (Giraffa giraffa) modulate insectivorous bat communities around permanent waterholes in the Namib Desert. We estimated megaherbivore use of sites based on dung transects, summarized vegetation productivity from satellite measurements of the normalized difference vegetation index, and surveyed local bat communities acoustically. We used structural equation models to identify relationships among megaherbivores and bat species richness and dry- (November 2016-January 2017) and wet- (February-May 2017) season bat activity. Site-level megaherbivore use in the dry season was positively associated with bat activity-particularly that of open-air foragers-and species richness through indirect pathways. When resources were more abundant (wet season), however, these relationships were weakened. Our results indicate that biotic interactions contribute to species distributions in desert areas and suggest the conservation of megaherbivores in this ecosystem may indirectly benefit insectivorous bat abundance and diversity. Given that how misunderstood and understudied most bats are relative to other mammals, such findings suggest that managers pursue short-term solutions (e.g., community game guard programs, water-point protection near human settlements, and ecotourism) to indirectly promote bat conservation and that research includes megaherbivores' effects on biodiversity at other trophic levels.
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Affiliation(s)
- Theresa M Laverty
- Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Joel Berger
- Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, Colorado, USA
- Wildlife Conservation Society, Bronx, New York, USA
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Islas CA, Seixas CS, Verdade LM. Wildlife–Human Survey: a rapid appraisal tool to assess mammal diversity and human–wildlife interactions in rural settings. WILDLIFE RESEARCH 2022. [DOI: 10.1071/wr20189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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7
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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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8
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Wilson LJ, Hoffman MT, Ferguson AJ, Cumming DH. Elephant browsing impacts in a Zambezian Baikiaea woodland with a high density of pumped waterholes. Glob Ecol Conserv 2021. [DOI: 10.1016/j.gecco.2021.e01854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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9
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Short duration overnight cattle kraaling in natural rangelands leads to increased tree damage by elephants. JOURNAL OF TROPICAL ECOLOGY 2021. [DOI: 10.1017/s0266467421000353] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractElephants are attracted to nutrient hotspots created through short duration overnight cattle corralling (hereafter kraaling) in natural rangelands at Debshan, a mixed cattle-wildlife private ranch in central Zimbabwe, causing severe tree damage. We determined the effect of age of nutrient hotspot (i.e., time after kraal use) on elephant use and the extent of tree damage. Elephant use and tree damage were assessed in nutrient hotspots of varying ages (6, 12, 24, 36 and 48 months after kraal use) and in surrounding landscape. We also compared Acacia karroo bark nutrient and soil nutrient concentration between nutrient hotspots (24 months after kraal use) and the surrounding landscape. Elephant use of nutrient hotspots was highest at 12 and 24 months after kraaling. The most severely damaged trees were in the 12-, 24- and 36-month-old nutrient hotspots. Acacia karroo bark nutrient concentrations (nitrogen, potassium, calcium, magnesium and iron) were higher in nutrient hotspots than surrounding vegetation, while soil nutrients (nitrogen, phosphorus, calcium and potassium) were higher in nutrient hotspots than surrounding landscape. We concluded that elephants mostly used nutrient hotspots 12 and 24 months after kraaling, while severe tree damage occurred 12, 24 and 36 months after kraal use.
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Titcomb GC, Amooni G, Mantas JN, Young HS. The effects of herbivore aggregations at water sources on savanna plants differ across soil and climate gradients. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2021; 31:e02422. [PMID: 34288228 DOI: 10.1002/eap.2422] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 01/29/2021] [Accepted: 03/22/2021] [Indexed: 06/13/2023]
Abstract
Water sources in arid and semiarid ecosystems support humans, wildlife, and domestic animals, forming nodes of activity that sculpt surrounding plant communities and impact critical grazing and soil systems. However, global aridification and changing surface water supply threaten to disrupt these water resources, with strong implications for conservation and management of these ecosystems. To understand how effects of herbivore aggregation at water impact plant communities across contexts, we measured herbivore activity, plant height, cover (trees, grasses, forbs, and bare ground), diversity, and composition at 17 paired water sources and matrix sites across a range of abiotic factors in a semiarid savanna in Kenya. The effects of proximity to surface water and herbivore aggregation on plant communities varied substantially depending on soil and rainfall. In arid areas with nutrient-poor sandy soils, forb and tree cover were 50% lower at water sources compared to neighboring matrix sites, bare ground was 20% higher, species richness was 15% lower, and a single globally important grazing grass (Cynodon dactylon) dominated 60% of transects. However, in mesic areas with nutrient-rich finely textured soils, species richness was 25% higher, despite a 40% increase in bare ground, concurrent with the decline of a dominant tall grass (Themeda triandra) and increase in C. dactylon and other grass species near water sources. Recent rainfall was important for grasses; cover was higher relative to matrix sites only during wet periods, a potential indication of compensatory grazing. These findings suggest that effects of herbivore aggregation on vegetation diversity and composition will vary in magnitude, and in some cases direction, depending on other factors at the site. Where moisture and nutrient resources are high and promote the dominance of few plant species, herbivore aggregations may maintain diversity by promoting grazing lawns and increasing nondominant species cover. However, in arid conditions and sites with low nutrient availability, diversity can be substantially reduced by these aggregations. Our results highlight the importance of considering abiotic conditions when managing for effects of herbivore aggregations near water. This will be particularly important for future managers in light of growing global aridification and surface water changes.
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Affiliation(s)
- Georgia C Titcomb
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, California, 93106, USA
- Mpala Research Centre, Box 555, Nanyuki, 10400, Kenya
| | | | | | - Hillary S Young
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, California, 93106, USA
- Mpala Research Centre, Box 555, Nanyuki, 10400, Kenya
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11
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Monitoring sun bears and Asiatic black bears with remotely sensed predictors to inform conservation management. ORYX 2021. [DOI: 10.1017/s0030605318001187] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
AbstractAsiatic black bear Ursus thibetanus and sun bear Helarctos malayanus populations are declining throughout South-east Asia as a result of habitat loss and human disturbance. Knowledge of the distribution and status of each species is limited and largely anecdotal. Range maps are coarse, compiled by expert opinion, and presence or absence is unknown over large portions of South-east Asia. These two species co-occur in Lao People's Democratic Republic and may be faring better there than in neighbouring countries. During 2010–2013 we searched for bear sign along 99 transects within eight study sites throughout Lao. To explore countrywide relative abundance and habitat suitability, we modelled bear sign as a log-linear function of biological and anthropogenic predictors that were associated with habitat assemblages and human disturbance. Bears favored higher elevations and rugged terrain in areas less accessible to humans, and were most abundant in the north and east of Lao. Suitable habitats were rare in the southern lowland plains where bear abundance was relatively low. Our model predicted that Nam Et–Phou Louey National Protected Area had the largest areas of suitable bear habitat, followed by the Nakai-Nam Teun and Nam Ha National Protected Areas. Using transects to survey for bear sign, we created a replicable geographical information system based assessment tool for bears in Lao that can be used to identify conservation opportunities and monitor changes in bear distribution over time.
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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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Müller B, Mercker M, Brün J. Population size estimates based on the frequency of genetically assigned parent-offspring pairs within a subsample. Ecol Evol 2020; 10:6356-6363. [PMID: 32724517 PMCID: PMC7381586 DOI: 10.1002/ece3.6365] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 03/09/2020] [Accepted: 04/17/2020] [Indexed: 01/28/2023] Open
Abstract
Estimating population density as precise as possible is a key premise for managing wild animal species. This can be a challenging task if the species in question is elusive or, due to high quantities, hard to count. We present a new, mathematically derived estimator for population size, where the estimation is based solely on the frequency of genetically assigned parent-offspring pairs within a subsample of an ungulate population. By use of molecular markers like microsatellites, the number of these parent-offspring pairs can be determined. The study's aim was to clarify whether a classical capture-mark-recapture (CMR) method can be adapted or extended by this genetic element to a genetic-based capture-mark-recapture (g-CMR). We numerically validate the presented estimator (and corresponding variance estimates) and provide the R-code for the computation of estimates of population size including confidence intervals. The presented method provides a new framework to precisely estimate population size based on the genetic analysis of a one-time subsample. This is especially of value where traditional CMR methods or other DNA-based (fecal or hair) capture-recapture methods fail or are too difficult to apply. The DNA source used is basically irrelevant, but in the present case the sampling of an annual hunting bag is to serve as data basis. In addition to the high quality of muscle tissue samples, hunting bags provide additional and essential information for wildlife management practices, such as age, weight, or sex. In cases where a g-CMR method is ecologically and hunting-wise appropriate, it enables a wide applicability, also through its species-independent use.
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Affiliation(s)
- Björn Müller
- Institute for Evolutionary Biology and EcologyUniversity of BonnBonnGermany
| | - Moritz Mercker
- Bionum‐Consultants in Biological, Ecological and Biomedical StatisticsHamburgGermany
| | - Jörg Brün
- Institute for Evolutionary Biology and EcologyUniversity of BonnBonnGermany
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Nyamukuru A. Wild mammal dung abundance in Lake Mburo National Park is lower than in adjacent ranchlands. NATURE CONSERVATION 2019. [DOI: 10.3897/natureconservation.37.35814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The establishment of livestock ranchlands adjacent to protected areas in savanna ecosystems is believed to threaten wild animals. Intensive competition for vegetative resources, water and poaching are considered to be immediate factors that reduce the capacity of protected areas to sustain wild mammals. The coexistence of wild mammals and ranchlands is common in Southern Africa but has rarely been suggested as a viable conservation option in East Africa. To assess the importance of ranchlands in conserving wild mammals, 36 plots of 20 × 20 m dimension were positioned along a 7240 m stretch from the boundary in Lake Mburo National Park (LMNP) and 36 plots of similar dimension were set within the ranchlands adjacent to the Park. The dung counts of different species recorded in the plots were used as a relative index of mammal abundance in the ranchlands and in LMNP. The results reveal 18 wild mammal species recorded in both sampled areas, 12 within LMNP and 17 in the adjacent ranchlands. The topi Damaliscus lunatus was only found in the park. Total dung count estimated in both ranchlands and LMNP was 2,586 with LMNP accounting for 29% and ranchlands 71%. In terms of wild mammal dung, ranchlands had a higher wild mammal dung count than LMNP (30% higher). The study points to the compatibility of the two land uses in conserving wild mammals and biodiversity in general, negating the common belief of competition and exclusion. Future research is needed on the compatibility of ranchlands with protected areas on biodiversity status of other species.
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Veblen KE, Porensky LM. Thresholds are in the eye of the beholder: plants and wildlife respond differently to short-term cattle corrals. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2019; 29:e01982. [PMID: 31348560 DOI: 10.1002/eap.1982] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 06/10/2019] [Accepted: 07/08/2019] [Indexed: 06/10/2023]
Abstract
Rangelands are governed by threshold dynamics, and factors such as drought, wildfire, and herbivory can drive change across thresholds and between ecological states. Most work on this topic has focused on shifts in a single response variable, vegetation, and little research has considered how to reconcile responses of more than one variable to determine whether a system has undergone a genuine state change. In sub-Saharan Africa, mobile overnight livestock corrals (bomas) can be used by managers to precipitate ecological transitions from areas dominated by bare ground to productive ecosystem hotspots (glades) that are attractive to wild herbivores. We asked how long bomas must be occupied by cattle before undergoing a state change, considering both plant and animal response variables, to glade ecosystem hotspots. We tested five durations of boma occupation: 0, 4, 7, 14, and 28 days. Each treatment was replicated five times, and we assessed vegetation as well as herbivore dung (as a proxy of use) at multiple time points over 3 yr following boma abandonment. Vegetation in 7-, 14-, and 28-d boma duration treatments appeared to undergo a complete transition to glade-like plant communities, whereas the shortest 4-d treatment had not converted to a glade plant community by year 3. Wildlife responses appeared to lag behind vegetation responses, with transitions to glade-like herbivore use occurring only in the longest duration (14- and 28-d) treatments. Our results show that different response variables, when considered individually, may provide incomplete or misleading information about state changes. Although shorter-occupied bomas might be effective for reducing bare ground, they may not attract enough wild herbivores to constitute crossing into an alternative state. Understanding threshold dynamics associated not only with vegetation responses but with a broader suite of response variables is challenging, but will provide a more complete representation of ecosystem function and greater opportunity for more successful ecosystem management.
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Affiliation(s)
- Kari E Veblen
- Department of Wildland Resources and Ecology Center, Utah State University, Logan, Utah, 84322, USA
- Mpala Research Centre, P.O. Box 555, Nanyuki, Kenya
| | - Lauren M Porensky
- Mpala Research Centre, P.O. Box 555, Nanyuki, Kenya
- USDA-ARS Rangeland Resources and Systems Research Unit, Fort Collins, Colorado, 80526, USA
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Fragoso JMV, Gonçalves F, Oliveira LFB, Overman H, Levi T, Silvius KM. Visual encounters on line transect surveys under-detect carnivore species: Implications for assessing distribution and conservation status. PLoS One 2019; 14:e0223922. [PMID: 31665170 PMCID: PMC6821099 DOI: 10.1371/journal.pone.0223922] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 10/01/2019] [Indexed: 11/19/2022] Open
Abstract
We compared the distribution and occurrence of 15 carnivore species with data collected monthly over three years by trained native trackers using both sign surveys and an encounter-based, visual-distance method in a well-preserved region of southern Guyana (Amazon / Guiana Shield). We found that a rigorously applied sign-based method was sufficient to describe the status of most carnivore species populations, including rare species such as jaguar and bush dog. We also found that even when accumulation curves for direct visual encounter data reached an asymptote, customarily an indication that sufficient sampling has occurred to describe populations, animal occurrence and distribution were grossly underestimated relative to the results of sign data. While other researchers have also found that sign are better than encounters or camera traps for large felids, our results are important in documenting the failure of even intensive levels of effort to raise encounter rates sufficiently to enable statistical analysis, and in describing the relationship between encounter and sign data for an entire community of carnivores including felids, canids, procyonids, and mustelids.
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Affiliation(s)
| | | | | | - Han Overman
- Environmental and Forest Biology, State University of New York-College of Environmental Science and Forestry, Syracuse, NY, United States of America
| | - Taal Levi
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR, United States of America
| | - Kirsten M. Silvius
- Department of Forest Resources and Environmental Conservation, Virginia Tech, Blacksburg, VA, United States of America
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Welch RJ, Grant T, Parker DM. Using Camera Traps to Generate a Species Inventory for Medium-Sized and Large Mammals in South West Zimbabwe. AFRICAN JOURNAL OF WILDLIFE RESEARCH 2019. [DOI: 10.3957/056.049.0089] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Affiliation(s)
- Rebecca J. Welch
- School of Biology & Environmental Sciences, University of Mpumalanga, Private Bag X11283, Nelspruit, 1200 South Africa
| | - Tanith Grant
- Wildlife & Reserve Management Research Group, Department of Zoology & Entomology, Rhodes University, P.O. Box 94, Grahamstown, 6140 South Africa
| | - Dan M. Parker
- School of Biology & Environmental Sciences, University of Mpumalanga, Private Bag X11283, Nelspruit, 1200 South Africa
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18
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Kiffner C, Arndt Z, Foky T, Gaeth M, Gannett A, Jackson M, Lellman G, Love S, Maroldi A, McLaughlin S, Skenandore B, von Euler S, Zambrano Z, Kissui B. Land use, REDD+ and the status of wildlife populations in Yaeda Valley, northern Tanzania. PLoS One 2019; 14:e0214823. [PMID: 30947305 PMCID: PMC6448838 DOI: 10.1371/journal.pone.0214823] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 03/20/2019] [Indexed: 11/19/2022] Open
Abstract
REDD+ projects primarily focus on reducing carbon emissions from deforestation and forest degradation in developing countries. These projects are regularly evaluated against their core objective of conserving carbon stocks, but their contribution to biodiversity conservation has rarely been assessed. To assess the conservation value of the area and the relative performance of a REDD+ land use plan in Yaeda Valley, a semi-arid savannah ecosystem in northern Tanzania, we implemented an annual wildlife monitoring scheme. Based on direct sightings and indirect signs of wildlife, obtained from stratified walking transects conducted annually from 2015–2018, we estimated annual trends of mammal species richness and wildlife densities in three REDD+ and three non-REDD+ land-use strata. Our surveys document a near complete mammal community in the area. Species accumulation curves, and subsequent statistical comparisons, indicated highest mammal species richness in the woodland habitats (both REDD+ and non REDD+ strata) as compared to more human and livestock impacted areas, and suggested constant species richness from 2015–2018. To estimate stratum- and year-specific livestock and wildlife densities (cattle, donkey, goat and sheep combined, Thomson’s gazelle, Kirk’s dik-dik) and wildlife sign densities (aardvark, bushbuck, bushpig, Kirk’s dik dik, eland, elephant, Maasai giraffe, greater kudu, hyena, impala, lesser kudu, warthog, wildebeest, Plains zebra), we fitted species-specific detection functions in a distance sampling framework. Species-specific densities varied between 2015 and 2018 and showed substantial increases and occasional declines in other species-stratum combinations. However, population growth rates were not systematically associated with specific land-use strata. Although our results do not explicitly provide evidence that REDD+ land-use plans directly co-benefit wildlife conservation, they show that REDD+ areas have the potential to maintain intact wildlife assemblages. To ensure effective long-term conservation outcomes, we advocate for a more formal integration of wildlife conservation goals in the REDD+ scheme.
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Affiliation(s)
- Christian Kiffner
- Center For Wildlife Management Studies, The School For Field Studies, Karatu, Tanzania
- * E-mail:
| | - Zoe Arndt
- Zoology Department, Colorado State University, Fort Collins, CO, United States of America
| | - Trent Foky
- Whitman College, Walla Walla, WA, United States of America
| | - Megan Gaeth
- Biology Department, Guilford College, Greensboro, North Carolina, United States of America
| | - Alex Gannett
- Environmental Studies, Gonzaga University, Spokane, WA, United States of America
| | - Madeline Jackson
- Ecology, Evolution and Behavior, University of Minnesota, St. Paul, MN, United States of America
| | | | - Sophia Love
- Whitman College, Walla Walla, WA, United States of America
| | - Ana Maroldi
- Department of Veterinary and Animal Science, University of Massachusetts-Amherst, Amherst, MA, United States of America
| | - Shane McLaughlin
- Environmental Science Program, Trinity College, Hartford, CT, United States of America
| | - Bobbi Skenandore
- Nelson Institute for Environmental Studies, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Sarah von Euler
- Biology Department, Davidson College, Davidson, NC, United States of America
| | - Zachary Zambrano
- Department of Animal Sciences and Industry, Kansas State University, Manhattan, KS, United States of America
| | - Bernard Kissui
- Center For Wildlife Management Studies, The School For Field Studies, Karatu, Tanzania
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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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Combining local knowledge and occupancy analysis for a rapid assessment of the forest elephant Loxodonta cyclotis in Cameroon's timber production forests. ORYX 2018. [DOI: 10.1017/s0030605317001569] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
AbstractInformation on the distribution and abundance of the forest elephant Loxodonta cyclotis is needed to allocate limited resources appropriately and set conservation goals for the species. However, monitoring at large scales in forest habitats is complicated, expensive and time consuming. We investigated the potential of applying interview-based occupancy analysis as a tool for the rapid assessment of the distribution and relative abundance of forest elephants in eastern Cameroon. Using single-season occupancy models, we explored the covariates that affect forest elephant occupancy and detectability, and identified spatial and temporal patterns in population change and occupancy. Quantitative and qualitative socio-demographic data offer additional depth and understanding, placing the occupancy analysis in context and providing valuable information to guide conservation action. Detectability of forest elephants has decreased since 2008, which is consistent with the decline in perceived abundance in occupied sites. Forest elephants occupy areas outside protected areas and outside the known elephant range defined by IUCN. Critical conservation attention is required to assess forest elephant populations and the threats they face in these poorly understood areas. Interview-based occupancy analysis is a reliable and suitable method for a rapid assessment of forest elephant occupancy on a large scale, as a complement to, or the first stage in, a monitoring process.
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21
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Yapi TS, O’Farrell PJ, Dziba LE, Esler KJ. Alien tree invasion into a South African montane grassland ecosystem: impact of Acacia species on rangeland condition and livestock carrying capacity. INTERNATIONAL JOURNAL OF BIODIVERSITY SCIENCE, ECOSYSTEM SERVICES & MANAGEMENT 2018. [DOI: 10.1080/21513732.2018.1450291] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Affiliation(s)
- Thozamile Steve Yapi
- Department of Conservation Ecology & Entomology, Stellenbosch University, Matieland, South Africa
- Natural Resources and the Environment, Council for Scientific and Industrial Research, Stellenbosch, South Africa
| | - Patrick J. O’Farrell
- Natural Resources and the Environment, Council for Scientific and Industrial Research, Stellenbosch, South Africa
- Percy FitzPatrick Institute of African Ornithology, University of Cape Town, Rondebosch, South Africa
| | - Luthando E. Dziba
- Natural Resources and the Environment, Council for Scientific and Industrial Research, Pretoria, South Africa
| | - Karen J. Esler
- Department of Conservation Ecology & Entomology, Stellenbosch University, Matieland, South Africa
- Centre for Invasion Biology, Stellenbosch University, Matieland, South Africa
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22
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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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Coverdale TC, Kartzinel TR, Grabowski KL, Shriver RK, Hassan AA, Goheen JR, Palmer TM, Pringle RM. Elephants in the understory: opposing direct and indirect effects of consumption and ecosystem engineering by megaherbivores. Ecology 2017; 97:3219-3230. [PMID: 27870025 DOI: 10.1002/ecy.1557] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 05/20/2016] [Accepted: 06/13/2016] [Indexed: 11/10/2022]
Abstract
Positive indirect effects of consumers on their resources can stabilize food webs by preventing overexploitation, but the coupling of trophic and non-trophic interactions remains poorly integrated into our understanding of community dynamics. Elephants engineer African savanna ecosystems by toppling trees and breaking branches, and although their negative effects on trees are well documented, their effects on small-statured plants remain poorly understood. Using data on 117 understory plant taxa collected over 7 yr within 36 1-ha experimental plots in a semi-arid Kenyan savanna, we measured the strength and direction of elephant impacts on understory vegetation. We found that elephants had neutral effects on most (83-89%) species, with a similar frequency of positive and negative responses among the remainder. Overall, estimated understory biomass was 5-14% greater in the presence of elephants across a range of rainfall levels. Whereas direct consumption likely accounts for the negative effects, positive effects are presumably indirect. We hypothesized that elephants create associational refuges for understory plants by damaging tree canopies in ways that physically inhibit feeding by other large herbivores. As predicted, understory biomass and species richness beneath elephant-damaged trees were 55% and 21% greater, respectively, than under undamaged trees. Experimentally simulated elephant damage increased understory biomass by 37% and species richness by 49% after 1 yr. Conversely, experimentally removing elephant damaged branches decreased understory biomass by 39% and richness by 30% relative to sham-manipulated trees. Camera-trap surveys revealed that elephant damage reduced the frequency of herbivory by 71%, whereas we detected no significant effect of damage on temperature, light, or soil moisture. We conclude that elephants locally facilitate understory plants by creating refuges from herbivory, which countervails the direct negative effects of consumption and enhances larger-scale biomass and diversity by promoting the persistence of rare and palatable species. Our results offer a counterpoint to concerns about the deleterious impacts of elephant "overpopulation" that should be considered in debates over wildlife management in African protected areas: understory species comprise the bulk of savanna plant biodiversity, and their responses to elephants are buffered by the interplay of opposing consumptive and non-consumptive interactions.
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Affiliation(s)
- Tyler C Coverdale
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, 08544, USA
| | - Tyler R Kartzinel
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, 08544, USA
| | - Kathryn L Grabowski
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, 08544, USA
| | - Robert K Shriver
- University Program in Ecology, Duke University, Durham, North Carolina, 27708, USA
| | | | - Jacob R Goheen
- Department of Zoology & Physiology, University of Wyoming, Laramie, Wyoming, 82071, USA
| | - Todd M Palmer
- Department of Biology, University of Florida, Gainesville, Florida, 32611, USA
| | - Robert M Pringle
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, 08544, USA
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Sianga K, Van Telgen M, Vrooman J, Fynn RW, Van Langevelde F. Spatial refuges buffer landscapes against homogenisation and degradation by large herbivore populations and facilitate vegetation heterogeneity. KOEDOE: AFRICAN PROTECTED AREA CONSERVATION AND SCIENCE 2017. [DOI: 10.4102/koedoe.v59i2.1434] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
Environmental heterogeneity across savanna landscapes, including different seasonal resources at different distances to water, may play a critical role in maintaining the size and diversity of wildlife populations and the sustainability of their resource base. We investigated whether extensive landscapes with functionally diverse seasonal resources and large waterless regions can mediate the effect of herbivory on plant composition, structure and diversity. Vegetation composition, structure and richness in two different vegetation types (mopane and sandveld woodland) at three distance zones (0 km – 5 km, 10 km – 15 km and > 20 km) from the permanent water of the Okavango Delta and Linyanti Swamps were surveyed. We modelled vegetation response of the most abundant species to herbivory in relation to distance from permanent water, and included fire frequency as a covariate. Trees favoured by elephants during the dry season occurred typically as immature, pollarded populations within 5 km of permanent water sources while mature tall populations of these species were found far from water (> 10 km – 15 km). Similarly, short high-quality grazing grasses were higher in abundance within 5 km of permanent water, whereas taller high-quality perennial grasses peaked in abundance beyond 20 km from permanent water. Trends in herbaceous richness with distance from water were contingent upon vegetation type, while tree richness did not change with distance from water. Spatial refuges in waterless regions of landscapes facilitate the creation of heterogeneity of vegetation structure, composition and richness by large herds of mammalian herbivores. Therefore, the extension of herbivore dry season foraging range, for example, by the creation of artificial water points (AWP) in backcountry woodlands, could seriously undermine the resilience of landscapes to herbivory by reducing the availability of spatial refuges. Consequently, it reduces the resilience of herbivore and predator populations that depend on these spatial refuges. We strongly advise that future scientific work, and management and policy actions should be focused on the identification and sustaining of these spatial refuges in wildlife areas.Conservation implications: Management and policy actions should be focused on the identification and sustainability of spatial refuges in wildlife areas. Too many AWP in backcountry woodlands could undermine the resilience of landscapes to herbivory by reducing the proportion of landscapes beyond 15 km from permanent water.
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Huruba R, Mundy PJ, Sebata A, Purchase GK, MacFadyen DN. Impala, Aepyceros melampus: does browse quality influence their use of sites originally utilised as short-duration kraals in a southern African savanna? RANGELAND JOURNAL 2017. [DOI: 10.1071/rj16016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In eastern and southern Africa, some ranch owners are now keeping cattle overnight in temporary corrals (hereafter referred to as kraals) within rangelands for short durations to improve grass production. However, this has profound effects on the woody plant community. For instance, cattle break woody plant stems and strip them of foliage, initiating resprouting. The resprouts produced have high foliar nitrogen (N) and reduced condensed tannin (CT) concentrations, making them attractive to herbivores. The aim of this study was to determine the key nutrient-quality parameters of resprouts that make previously kraaled sites attractive to impala soon after cattle removal at Debshan Ranch in central Zimbabwe. We determined resprout length, foliar N, phosphorus (P), potassium, CT, fibre and rumen fermentation of three browse species, viz. Grewia monticola Sond., Terminalia sericea Burch. ex DC. and Dichrostachys cinerea (L.) Wight and Arn., and related them to impala use of previously kraaled sites. We used impala dung density to determine the use patterns of previously kraaled sites 2, 4, 12 and 24 weeks after cattle removal and compared them with the surrounding vegetation. Impala use of previously kraaled sites was highest 4 weeks after cattle removal and lowest in the surrounding vegetation. Resprout length increments were 6-fold over a 10-week growth period in all three woody species. Foliar N and P were generally higher, whereas CT was lower, in previously kraaled sites than the surrounding vegetation in all three of the plant browse species. Impala use of previously kraaled sites showed a strong negative relationship with foliar CT. We conclude that kraaling initiates strong resprout responses by woody plants soon after cattle removal, to produce resprouts of high nutrient quality, which attract herbivores such as impala.
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Analyzing Vegetation Change in an Elephant-Impacted Landscape Using the Moving Standard Deviation Index. LAND 2014. [DOI: 10.3390/land3010074] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Månsson J, Hauser CE, Andrén H, Possingham HP. Survey method choice for wildlife management: the case of moose Alces alces in Sweden. WILDLIFE BIOLOGY 2011. [DOI: 10.2981/10-052] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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Rodríguez-Robles JA, Glaudas X. A two-level problem: habitat selection in relation to prey abundance in an ambush predator, the speckled rattlesnake (Crotalus mitchellii). BEHAVIOUR 2011. [DOI: 10.1163/156853912x623739] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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29
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Sensenig RL, Demment MW, Laca EA. Allometric scaling predicts preferences for burned patches in a guild of East African grazers. Ecology 2010; 91:2898-907. [DOI: 10.1890/09-1673.1] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Ryan L. Sensenig
- Department of Plant Sciences, University of California, Davis, California 95616 USA
- Mpala Research Centre, Box 555, Nanyuki, Kenya
| | - Montague W. Demment
- Department of Plant Sciences, University of California, Davis, California 95616 USA
| | - Emilio A. Laca
- Department of Plant Sciences, University of California, Davis, California 95616 USA
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Kouakou CY, Boesch C, Kuehl H. Estimating chimpanzee population size with nest counts: validating methods in Taï National Park. Am J Primatol 2009; 71:447-57. [PMID: 19235865 DOI: 10.1002/ajp.20673] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Successful conservation and management of wild animals require reliable estimates of their population size. Ape surveys almost always rely on counts of sleeping nests, as the animals occur at low densities and visibility is low in tropical forests. The reliability of standing-crop nest counts and marked-nest counts, the most widely used methods, has not been tested on populations of known size. Therefore, the answer to the question of which method is more appropriate for surveying chimpanzee population remains problematic and comparisons among sites are difficult. This study aimed to test the validity of these two methods by comparing their estimates to the known population size of three habituated chimpanzee communities in Taï National Park [Boesch et al., Am J Phys Anthropol 130:103-115, 2006; Boesch et al., Am J Primatol 70:519-532, 2008]. In addition to transect surveys, we made observations on nest production rate and nest lifetime. Taï chimpanzees built 1.143 nests per day. The mean nest lifetime of 141 fresh nests was 91.22 days. Estimate precision for the two methods did not differ considerably (difference of coefficient of variation <5%). The estimate of mean nest decay time was more precise (CV=6.46%) when we used covariates (tree species, rainfall, nest height and age) to model nest decay rate, than when we took a simple mean of nest decay times (CV=9.17%). The two survey methods produced point estimates of chimpanzee abundance that were similar and reliable: i.e. for both methods the true chimpanzee abundance was included within the 95% estimate confidence interval. We recommend further research on covariate modeling of nest decay times as one way to improve the precision and to reduce the costs of conducting nest surveys.
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Affiliation(s)
- Célestin Yao Kouakou
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.
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Olivier PI, Ferreira SM, van Aarde RJ. Dung survey bias and elephant population estimates in southern Mozambique. Afr J Ecol 2009. [DOI: 10.1111/j.1365-2028.2008.00983.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Cromsigt JPGM, Prins HHT, Olff H. Habitat heterogeneity as a driver of ungulate diversity and distribution patterns: interaction of body mass and digestive strategy. DIVERS DISTRIB 2009. [DOI: 10.1111/j.1472-4642.2008.00554.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Hibert F, Fritz H, Poilecot P, Abdou HN, Dulieu D. Morphological criteria to identify faecal pellets of sympatric ungulates in West African savanna and estimates of associated error. Afr J Ecol 2008. [DOI: 10.1111/j.1365-2028.2007.00889.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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34
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Bekhuis PDBM, De Jong CB, Prins HHT. Diet selection and density estimates of forest buffalo in Campo-Ma’an National Park, Cameroon. Afr J Ecol 2008. [DOI: 10.1111/j.1365-2028.2008.00956.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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35
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Todd AF, Kuehl HS, Cipolletta C, Walsh PD. Using Dung to Estimate Gorilla Density: Modeling Dung Production Rate. INT J PRIMATOL 2008. [DOI: 10.1007/s10764-008-9247-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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36
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Waldram MS, Bond WJ, Stock WD. Ecological Engineering by a Mega-Grazer: White Rhino Impacts on a South African Savanna. Ecosystems 2007. [DOI: 10.1007/s10021-007-9109-9] [Citation(s) in RCA: 182] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Blake S, Strindberg S, Boudjan P, Makombo C, Bila-Isia I, Ilambu O, Grossmann F, Bene-Bene L, de Semboli B, Mbenzo V, S'hwa D, Bayogo R, Williamson L, Fay M, Hart J, Maisels F. Forest elephant crisis in the Congo Basin. PLoS Biol 2007; 5:e111. [PMID: 17407383 PMCID: PMC1845159 DOI: 10.1371/journal.pbio.0050111] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2006] [Accepted: 02/21/2007] [Indexed: 11/18/2022] Open
Abstract
Debate over repealing the ivory trade ban dominates conferences of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Resolving this controversy requires accurate estimates of elephant population trends and rates of illegal killing. Most African savannah elephant populations are well known; however, the status of forest elephants, perhaps a distinct species, in the vast Congo Basin is unclear. We assessed population status and incidence of poaching from line-transect and reconnaissance surveys conducted on foot in sites throughout the Congo Basin. Results indicate that the abundance and range of forest elephants are threatened from poaching that is most intense close to roads. The probability of elephant presence increased with distance to roads, whereas that of human signs declined. At all distances from roads, the probability of elephant occurrence was always higher inside, compared to outside, protected areas, whereas that of humans was always lower. Inside protected areas, forest elephant density was correlated with the size of remote forest core, but not with size of protected area. Forest elephants must be prioritised in elephant management planning at the continental scale. Forest elephants, perhaps a distinct species of African elephant, occur in the forests of West and Central Africa. Compared to the more familiar savannah elephant of Eastern and Southern Africa, forest elephant biology and their conservation status are poorly known. To provide robust scientific data on the status and distribution of forest elephants to inform and guide conservation efforts, we conducted surveys on foot of forest elephant abundance and of illegal killing of elephants in important conservation sites throughout Central Africa. We covered a combined distance of over 8,000 km on reconnaissance walks, and we systematically surveyed a total area of some 60,000 km2 under the auspices of the Monitoring of the Illegal Killing of Elephants (MIKE) programme. Our results indicate that forest elephant numbers and range are severely threatened by hunting for ivory. Elephant abundance increased with increasing distance from the nearest road, and poaching pressure was most concentrated near roads. We found that protected areas have a positive impact on elephant abundance, probably because management interventions reduced poaching rates inside protected areas compared to non-protected forest. Law enforcement to bring the illegal ivory trade under control, and effective management and protection of large and remote national parks will be critical if forest elephants are to be successfully conserved. A systematic survey of 68,000 km2 throughout Central Africa reveals that the forest elephant--distinct from the savannah elephant--is severely threatened by poaching, despite a near universal ban of trade in ivory.
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Affiliation(s)
- Stephen Blake
- Africa Program, Wildlife Conservation Society, Bronx, New York, United States of America.
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Eggert LS, Eggert JA, Woodruff DS. Estimating population sizes for elusive animals: the forest elephants of Kakum National Park, Ghana. Mol Ecol 2003; 12:1389-402. [PMID: 12755869 DOI: 10.1046/j.1365-294x.2003.01822.x] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
African forest elephants are difficult to observe in the dense vegetation, and previous studies have relied upon indirect methods to estimate population sizes. Using multilocus genotyping of noninvasively collected samples, we performed a genetic survey of the forest elephant population at Kakum National Park, Ghana. We estimated population size, sex ratio and genetic variability from our data, then combined this information with field observations to divide the population into age groups. Our population size estimate was very close to that obtained using dung counts, the most commonly used indirect method of estimating the population sizes of forest elephant populations. As their habitat is fragmented by expanding human populations, management will be increasingly important to the persistence of forest elephant populations. The data that can be obtained from noninvasively collected samples will help managers plan for the conservation of this keystone species.
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Affiliation(s)
- L S Eggert
- Ecology, Behavior and Evolution Section, Division of Biological Sciences, University of California, San Diego 92093-0116, USA.
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39
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Barnes RFW. The problem of precision and trend detection posed by small elephant populations in West Africa. Afr J Ecol 2002. [DOI: 10.1046/j.1365-2028.2002.00376.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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