Potts J.M.,University of St. Andrews |
Potts J.M.,University of Melbourne |
Buckland S.T.,University of St. Andrews |
Thomas L.,University of St. Andrews |
Savage A.,Disneys Animal Kingdom
Methods in Ecology and Evolution | Year: 2012
1. Obtaining robust abundance or density estimates is problematic for many rare or cryptic species. We combine elements of capture-recapture and distance sampling, to develop a method called trapping point transects (TPT), and we applied this method to estimate the abundance of the endangered Key Largo woodrat (Neotoma floridana smalli). 2. Trapping point transects requires two separate surveys to be held concurrently in space and time. In the main survey, the encounter rate (number of animals caught per trap per session) is measured. In the trial survey, animals whose locations are known prior to opening traps are used to estimate the detection function g(r) (the probability of capturing an animal given it is distance r from a trap when it is set), so the effective trapping area in the main survey can be estimated. It is assumed animals in the trial survey are a representative sample of all animals in the population. Individual heterogeneity in trappability is accommodated using randomeffects in g(r). 3. Performance of two TPT estimators was assessed by simulation. Generally, when underlying capture probabilities were high [g(0) = 0.8] and between-individual variation was small, modest survey effort (360 trap nights in the trial survey) generated little bias in estimated abundance (c. 5%). Uncertainty and relative bias in population estimates increased with decreasing capture probabilities and increasing between-individual variation. Survey effort required to obtain unbiased estimates was also investigated. 4. Given the challenges of working with cryptic, sparse or nocturnal species, we tested the validity of this method to estimate the abundance of the Key Largo woodrats between 2008 and 2011. 5. Trapping point transects was found to be an effective monitoring method yielding annual estimates of the extant wild population of 693, 248, 78 and 256 animals, with CVs of 0.45, 0.55, 0.82 and 0.43, respectively. The TPT method could be adapted to a range of species that are otherwise very difficult tomonitor.© 2012 The Authors. Methods in Ecology and Evolution. © 2012 British Ecological Society.
Savage A.,Disneys Animal Kingdom
American Journal of Primatology | Year: 2010
Developing effective conservation programs that positively impact the survival of a species while considering the needs of local communities is challenging. Here we present an overview of the conservation program developed by Proyecto Tití to integrate local communities in the conservation of Colombia's critically endangered primate, the cotton-top tamarin (Saguinus oedipus). Our comprehensive assessment of the threats effecting the long-term survival of the cotton-top tamarin allowed us to establish the primary components of our program. Proyecto Tití has three areas of emphasis: (1) scientific studies detailing the biology and long-term survival of the cotton-top tamarin, (2) conservation education programs to increase public awareness and conservation knowledge, and (3) community empowerment programs that demonstrate a valuable economic incentive to protecting wildlife and forested areas in Colombia. This integrated approach to conservation that involves local communities in activities that benefit individuals, as well as wildlife, has proven to be remarkably effective in protecting cotton-top tamarins and their forested habitat. Our bindes program, which uses small cook stoves made from clay, has demonstrated a marked reduction in the number of trees that have been harvested for firewood. Developing environmental entrepreneurs, who create products made from recycled plastic for sale in national and international markets, has had a significant impact in reducing the amount of plastic that has been littering the environment and threatening the health of wildlife, while creating a stable economic income for rural communities. Proyecto Tití has provided economic alternatives to local communities that have dramatically reduced the illegal capture of cotton-top tamarins and forest destruction in the region that has positively impacted the long-term survival of this critically endangered primate. © 2009 Wiley-Liss, Inc.
Savage A.,Disneys Animal Kingdom
Nature communications | Year: 2010
The cotton-top tamarin (Saguinus oedipus) is a critically endangered primate, endemic to the tropical forests of Colombia. Population monitoring is essential to evaluate the success of conservation efforts, yet standard survey methods are ineffective because animals flee silently before they are seen. We developed a novel technique that combines the use of playbacks of territorial vocalizations with traditional transect surveys. We used remote sensing to identify potential habitat within the species' historic range, and visited the 27% that we could survey safely. Of this, only 99 km(2) was extant forest, containing an estimated 2,045 animals (95% confidence interval 1,587-2,634). Assuming comparable densities in non-surveyed areas, approximately 7,394 wild cotton-top tamarins remain in Colombia. With 20-30,000 animals exported to the United States in the late 1960s, this must represent a precipitous decline. Habitat destruction and capture for the illegal pet trade are ongoing. Urgent conservation measures are required to prevent extinction in the wild.
Morfeld K.A.,Smithsonian Conservation Biology Institute |
Lehnhardt J.,National Elephant Center |
Alligood C.,Disneys Animal Kingdom |
Bolling J.,National Elephant Center |
Brown J.L.,Smithsonian Conservation Biology Institute
PLoS ONE | Year: 2014
Obesity-related health and reproductive problems may be contributing to non-sustainability of zoo African elephant (Loxodonta africana) populations. However, a major constraint in screening for obesity in elephants is lack of a practical method to accurately assess body fat. Body condition scoring (BCS) is the assessment of subcutaneous fat stores based on visual evaluation and provides an immediate appraisal of the degree of obesity of an individual. The objective of this study was to develop a visual BCS index for female African elephants and validate it using ultrasound measures of subcutaneous fat. To develop the index, standardized photographs were collected from zoo (n = 50) and free-ranging (n = 57) female African elephants for identifying key body regions and skeletal features, which were then used to visually determine body fat deposition patterns. This information was used to develop a visual BCS method consisting of a list of body regions and the physical criteria for assigning an overall score on a 5-point scale, with 1 representing the lowest and 5 representing the highest levels of body fat. Results showed that as BCS increased, ultrasound measures of subcutaneous fat thickness also increased (P<0.01), indicating the scores closely coincide with physical measures of fat reserves. The BCS index proved to be reliable and repeatable based on high intra- and inter-assessor agreement across three assessors. In comparing photographs of wild vs. captive African elephants, the median BCS in the free-ranging individuals (BCS = 3, range 1-5) was lower (P<0.001) than that of the zoo population (BCS = 4, range 2-5). In sum, we have developed the first validated BCS index for African elephants. This tool can be used to examine which factors impact body condition in zoo and free-ranging elephants, providing valuable information on how it affects health and reproductive potential of individual elephants.
King L.E.,University of Oxford |
Soltis J.,Disneys Animal Kingdom |
Douglas-Hamilton I.,University of Oxford |
Savage A.,Disneys Animal Kingdom |
Vollrath F.,University of Oxford
PLoS ONE | Year: 2010
Unlike the smaller and more vulnerable mammals, African elephants have relatively few predators that threaten their survival. The sound of disturbed African honeybees Apis meliffera scutellata causes African elephants Loxodonta Africana to retreat and produce warning vocalizations that lead other elephants to join the flight. In our first experiment, audio playbacks of bee sounds induced elephants to retreat and elicited more head-shaking and dusting, reactive behaviors that may prevent bee stings, compared to white noise control playbacks. Most importantly, elephants produced distinctive "rumble" vocalizations in response to bee sounds. These rumbles exhibited an upward shift in the second formant location, which implies active vocal tract modulation, compared to rumbles made in response to white noise playbacks. In a second experiment, audio playbacks of these rumbles produced in response to bees elicited increased headshaking, and further and faster retreat behavior in other elephants, compared to control rumble playbacks with lower second formant frequencies. These responses to the bee rumble stimuli occurred in the absence of any bees or bee sounds. This suggests that these elephant rumbles may function as referential signals, in which a formant frequency shift alerts nearby elephants about an external threat, in this case, the threat of bees. © 2010 King.et al.