scholarly journals Assessing population structure and body condition to inform conservation strategies for a small isolated Asian elephant (Elephas maximus) population in southwest China

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248210
Author(s):  
Yakuan Sun ◽  
Ying Chen ◽  
Juan José Díaz-Sacco ◽  
Kun Shi
Keyword(s):  
Population Structure ◽  
Body Condition ◽  
Asian Elephant ◽  
Elephas Maximus ◽  
Conservation Strategies ◽  
Limiting Factor ◽  
Sampling Effort ◽  
Adult Males ◽  
Adult Females ◽  
Elephant Population

The Asian elephant (Elephas maximus) population in Nangunhe National Nature Reserve in China represents a unique evolutionary branch that has been isolated for more than twenty years from neighboring populations in Myanmar. The scarcity of information on population structure, sex ratio, and body condition makes it difficult to develop effective conservation measures for this elephant population. Twelve individuals were identified from 3,860 valid elephant images obtained from February to June 2018 (5,942 sampling effort nights) at 52 camera sites. Three adult females, three adult males, one subadult male, two juvenile females, two juvenile males and one male calf were identified. The ratio of adult females to adult males was 1:1, and the ratio of reproductive ability was 1:0.67, indicating the scarcity of reproductive females as an important limiting factor to population growth. A population density of 5.32 ± 1.56 elephants/100 km2 was estimated using Spatially Explicit Capture Recapture (SECR) models. The health condition of this elephant population was assessed using an 11-point scale of Body Condition Scoring (BCS). The average BCS was 5.75 (n = 12, range 2–9), with adult females scoring lower than adult males. This isolated population is extremely small and has an inverted pyramid age structure and therefore is at a high risk of extinction. We propose three plans to improve the survival of this population: improving the quality and quantity of food resources, removing fencing and establishing corridors between the east and wet parts of Nangunhe reserve.

scholarly journals Social structure and demography of a remnant Asian elephant Elephas maximus population and the implications for survival

Oryx ◽  
2020 ◽  
pp. 1-6
Author(s):  
Lauren J. Hale ◽  
Kun Shi ◽  
Tania C. Gilbert ◽  
Kelvin S.-H. Peh ◽  
Philip Riordan
Keyword(s):  
Social Structure ◽  
Population Size ◽  
Total Population ◽  
Camera Traps ◽  
Asian Elephant ◽  
Elephas Maximus ◽  
Effective Density ◽  
Anthropogenic Pressures ◽  
Sex Ratio Bias ◽  
Elephant Population

Abstract The Asian elephant Elephas maximus is at risk of extinction as a result of anthropogenic pressures, and remaining populations are often small and fragmented remnants, occupying a fraction of the species' former range. Once widely distributed across China, only a maximum of 245 elephants are estimated to survive across seven small populations. We assessed the Asian elephant population in Nangunhe National Nature Reserve in Lincang Prefecture, China, using camera traps during May–July 2017, to estimate the population size and structure of this genetically important population. Although detection probability was low (0.31), we estimated a total population size of c. 20 individuals, and an effective density of 0.39 elephants per km2. Social structure indicated a strong sex ratio bias towards females, with only one adult male detected within the population. Most of the elephants associated as one herd but three adult females remained separate from the herd throughout the trapping period. These results highlight the fragility of remnant elephant populations such as Nangunhe and we suggest options such as a managed metapopulation approach for their continued survival in China and more widely.

scholarly journals Modelling harvest of Asian elephants Elephas maximus on the basis of faulty assumptions promotes inappropriate management solutions

Oryx ◽  
2016 ◽  
Vol 51 (3) ◽  
pp. 506-512 ◽  
Author(s):  
Jean Philippe Puyravaud ◽  
Priya Davidar ◽  
Rajeev K. Srivastava ◽  
Belinda Wright
Keyword(s):  
Population Structure ◽  
Logistic Model ◽  
Transition Probabilities ◽  
Elephas Maximus ◽  
Management Tool ◽  
Tiger Reserve ◽  
Deterministic Modelling ◽  
Elephant Population ◽  
Regional Population ◽  
Harvest Regimes

AbstractA ratio-based logistic model developed to assess elephant harvest rates, based on a study at Nagarhole Tiger Reserve in India, was recommended as a management tool to control human–elephant conflict through culling. Considering this reserve among others violates an assumption of the logistic model: isolation. Nevertheless, assuming this violation was irrelevant, we re-evaluated the model, with minor modifications, for the neighbouring Mudumalai Tiger Reserve, where we used data from 13 elephant Elephas maximus population surveys to derive bootstrapped sets of population ratios, and mortality records. We generated arrays of harvest regimes and examined which ratio outputs were closest to the bootstrapped ratios. Our results indicated that (1) model outputs corresponded best with the Mudumalai population structure when harvest regimes were extreme and unlikely, (2) there were significant differences in population structure and harvest regimes between Nagarhole and Mudumalai, and (3) only 49% of adult male deaths predicted by model outputs were recorded in official governmental records. The model provides significantly different results among reserves, which invalidates it as a tool to predict change across the entire elephant population. Variability in survey data and inaccuracies in transition probabilities are sufficiently large to warrant caution when using them as a basis for deterministic modelling. Official mortality databases provide a weak means of validation because poaching incidents are poorly recorded. We conclude that the model should be based on validated transition probabilities and encompass the entire regional population.

scholarly journals Fat mass compared to four body condition scoring systems in the Asian elephant ( Elephas maximus)

Zoo Biology ◽  
2019 ◽  
Vol 38 (5) ◽  
pp. 424-433 ◽  
Author(s):  
Daniella E. Chusyd ◽  
Janine L. Brown ◽  
Lilian Golzarri‐Arroyo ◽  
Stephanie L. Dickinson ◽  
Maria S. Johnson ◽  
...  
Keyword(s):  
Body Condition ◽  
Fat Mass ◽  
Scoring Systems ◽  
Asian Elephant ◽  
Elephas Maximus ◽  
Body Condition Scoring

scholarly journals Timing of emergence and cave return, and duration of nocturnal activity in an endemic Malagasy fruit bat

2020 ◽  
Vol 33 (1) ◽  
Author(s):  
Riana V. Ramanantsalama ◽  
Steven M. Goodman
Keyword(s):  
Ecosystem Services ◽  
Body Condition ◽  
Dry Season ◽  
Adult Males ◽  
Nocturnal Activity ◽  
Wet Season ◽  
Fruit Bat ◽  
Adult Females ◽  
Narrow Passage ◽  
Age And Sex

Bats emerge from their day roost after dusk and different factors can affect the timing of departure, return, and duration of nocturnal activities. This study provides information on the time of emergence and return of an endemic Malagasy fruit bat, Rousettus madagascariensis, in a cave located in the Réserve Spéciale d’Ankarana, northern Madagascar. Individuals were captured in a narrow passage between the roost and cave exit and capture time for each individual was noted. Variation according to sex, age, and body condition, as well as the influence of season, and the sunset and sunrise time were analyzed. During the dry season, individuals started to emerge at 1913 hours and returned to the cave generally by 0505 hours; the duration of time outside the cave during the dry season was higher in adult females (0952 hours) followed by subadult males (0937 hours), sub-adult females (0931 hours), and adult males (0910 hours). During the wet season, individuals exited at 1926 hours and returned at 0351 hours; as in the dry season, adult females spent more time outside the cave (0833 hours), than sub-adult females (0800 hours), and adult males (0752 hours). The period of emergence varied according to the age and sex classes, and time of predawn return associated with the previous nocturnal activity. The period of return was influenced by season, and age and sex classes. Such information is useful to quantify shifts in bat ecology, especially for endemic species with limited distribution or those playing an important role in ecosystem services.

scholarly journals NATURAL HISTORY OF DEKAY’S BROWNSNAKE, STORERIA DEKAYI (HOLBROOK, 1836), AT A SITE IN NORTHWESTERN PENNSYLVANIA

2014 ◽  
pp. 28-39
Author(s):  
Brian S. Gray
Keyword(s):  
Population Structure ◽  
Site Fidelity ◽  
Additional Data ◽  
Tail Length ◽  
Adult Males ◽  
Morphometric Data ◽  
Erie County ◽  
Adult Females ◽  
History Of ◽  
A Site

A population of Dekay’s Brownsnake, Storeria dekayi was studied using mark-recapture techniques in Erie County, Pennsylvania, USA during the spring, summer and autumn of 2012. Morphometric data were similar to that reported for the species, with adult females averaging larger and more massive than adult males. However, sexual dimorphism in snout-vent length (SVL) and total length (TL) was not significantly different (P>0.05) in juveniles, although relative tail length (tl/TL) was dimorphic. Relative tail length in both juveniles and adults was greater in males (tl/TL = 0.22-0.27) than females (tl/TL = 0.18-0.23). Storeria dekayi were active from 21 March through 22 October, and displayed a bimodal activity pattern, with peaks in April and August. Using the Schnabel and the Schumacher-Eschmeyer methods, population size was estimated to be 122 ± 19 and 130 ± 35 individuals, respectively. Density was estimated to be 244 and 260 snakes/ha, and biomass 1.60 and 1.71 kg/ha. Additional data regarding population structure, mortality, diet, reproduction, body temperature, movements and site fidelity are also presented.

scholarly journals Struktur Populasi Kelelawar (Tylonycteris pachypus) yang Bersarang pada Bambu (Bambusa maculata) di Dusun Jangkok, Kecamatan Air Besar, Kabupaten Landak

2019 ◽  
Vol 8 (2) ◽  
Author(s):  
Salomon Tri Rima Setyawati, Ari Hepi Yanti
Keyword(s):  
Population Structure ◽  
Data Collection ◽  
Total Population ◽  
Rubber Plantation ◽  
Adult Males ◽  
Adult Females ◽  
Mark Release Recapture

Tylonycteris pachypus is included into Vespertilonidae family which nesting in bamboo (Bambusa maculata) in rubber plantation of Jangkok Hamlet, Air Besar Sub-District, Landak District. The aim of this study was to determine the population structure of bats and the characteristics of bamboo nests. Data collection was carried out from May to July 2017. The method used was Capture Mark Release Recapture (CMRR), the bats caught were marked with red-oil paint on the back. The results showed that one group of T. pachypus nesting in bamboo consisted of 2 adult males, 1 male young bat, and 6 adult females. The estimated total population of 14 estimated population is (SE ± 2,09). The bamboo cavity that is made as the nest by             T. pachypus has a smooth inner-wall texture, moist, with a section length of 406 mm, a diameter of 41 mm, and it is at the altitude of 1870 mm above the ground. Cracks or inlets on bamboo as the entrance is small and narrow with a vertical length of 33 mm and a horizontal width of 8-10 mm.

The quantitative effects of population density and winter weather on the body condition of white-tailed deer (Odocoileus virginianus) in Nova Scotia, Canada

2005 ◽  
Vol 83 (9) ◽  
pp. 1246-1256 ◽  
Author(s):  
Colin J Garroway ◽  
Hugh G Broders
Keyword(s):  
Odocoileus Virginianus ◽  
Body Condition ◽  
Snow Depth ◽  
Information Criterion ◽  
The Body ◽  
Adult Males ◽  
Winter Weather ◽  
Adult Females ◽  
Deer Density ◽  
Effects Of Density

Understanding the underlying mechanisms that cause variation in survival and the reproductive success of animals is essential for predicting variation in population parameters. To gain an understanding of the effects of density and winter weather severity on white-tailed deer, Odocoileus virginianus (Zimmermann, 1780), we examined the effects of current-year deer density and cumulative weekly average values for snow depth, rainfall, and the number of degrees below –15 °C until the time of death, as well as cumulative effects of density and snow depth over the previous one and two winters, on the body condition of adult females, adult males, and fawns. Model selection using Akaike's Information Criterion and multi-model inference suggested that snow depth was the best predictor of body condition for all three age/sex groups. Winter rainfall was the next most influential predictor for adult females and adult males but was not important in determining fawn body condition. Temperature had the least influence on the body condition of all three age/sex groups. Deer density during the winter of death had minimal effects for all groups and we found no evidence that cumulative multiyear variables influenced body condition. We hypothesize that cohort variation may better explain previous findings showing effects of multiyear variables. A model for estimating the proportion of animals in poor body condition for each age/sex group is presented.

scholarly journals Population Structure of Mesoclemmys vanderhaegei (Bour, 1973) (Testudines:Chelidae) in the Cerrado of Chapada dos Guimarães, Mato Grosso, Brazil

2009 ◽  
Vol 9 (4) ◽  
pp. 245-248 ◽  
Author(s):  
Elizângela Silva de Brito ◽  
Christine Strussmann ◽  
Jerry Magno Ferreira Penha
Keyword(s):  
Population Structure ◽  
Freshwater Turtles ◽  
Adult Males ◽  
Mato Grosso ◽  
Adult Females ◽  
The Family ◽  
Number Of Individuals

Studies on population structure of freshwater turtles belonging to the family Chelidae are scarce in Brazil. Herein we describe the structure of a population of the chelid Mesoclemmys vanderhaegei in a Cerrado area in the municipality of Chapada dos Guimarães, Mato Grosso, Brazil. A total of 80 individuals were captured in five collecting sites, from January to March 2007: 42 adult females, 27 adult males, and 11 juveniles with undetermined sex. Among 80 individuals, 24% were recaptured, at least once. This is the first attempt to estimate the size of a population of Mesoclemmys vanderhaegei. Our results suggest that additional sampling efforts are needed for more accurate estimates of population structure. Nevertheless, they surely provide minimum values of the number of individuals of M. vanderhaegei living in the locality sampled.

scholarly journals Experimenting usage of Camera-traps for Population Dynamics Study of the Asian Elephant Elephas Maximus in Southern India

2007 ◽  
Vol 6 (1) ◽  
pp. 81-95
Author(s):  
Surendra Varma ◽  
André Pittet ◽  
H. S. Jamadagni
Keyword(s):  
Population Dynamics ◽  
Cost Effective ◽  
Camera Trap ◽  
Camera Traps ◽  
Asian Elephant ◽  
Adult Males ◽  
Adult Females ◽  
Juvenile Males ◽  
Long Term Studies

To evaluate the application of camera-trap technology in population dynamics studies of the Asian elephant, indigenously designed, cost-effective, infrared-triggered camera-traps were used.Usability of pictures was defined based on quality, clarity and positioning of the subject.With 99 pictures of 330 elephants, 20 sequences were obtained and 44 distinct individuals were identified.It was found that 38.6% were adult females, 4.5% adult males, 13.6% sub-adult females, 6.8% sub-adult males, 20.4% juvenile females,while juvenile males were poorly represented(2%), and 13.6% were calves.These results were surprising identical with those of other systematic and long-term studies.

scholarly journals Population and distribution of wild Asian elephants (Elephas maximus) in Phu Khieo Wildlife Sanctuary, Thailand

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11896
Author(s):  
Nyi Nyi Phyo Htet ◽  
Rattanawat Chaiyarat ◽  
Nikorn Thongthip ◽  
Panat Anuracpreeda ◽  
Namphung Youngpoy ◽  
...  
Keyword(s):  
Management Practices ◽  
Population Distribution ◽  
Habitat Preferences ◽  
Camera Trap ◽  
Elephas Maximus ◽  
Suitable Habitat ◽  
Adult Males ◽  
Wildlife Sanctuary ◽  
Asian Elephants ◽  
Adult Females

Background The populations of wild Asian elephants (Elephas maximus) have increased recently after a period of worldwide decline in protected areas. It is important to understand the dynamics and distribution of the remaining populations to ensure their conservation and prevent human-elephant conflicts. Methods We monitored the population distribution of elephants between 2016 and 2019 in the Phu Khieo Wildlife Sanctuary, Thailand. We set one hundred forty-nine camera trap locations; cameras recorded 38,834 photos over 6,896 trap nights. Elephants were captured in 4,319 photographs. The maximum entropy modeling software MaxEntwas used to identify elephants’ habitat preferences within 49 of the 149 total camera trap locations according to five environmental factors. Results One hundred fourteen elephants were identified. We identified 30 adult males, 43 adult females, 14 sub-adult males, nine sub-adult females, 11 juveniles, and seven calves. The age structure ratio based on adult femaleswas 0.7:1:0.3:0.2:0.3:0.2, and the ratio of reproductive ability between adult females, juveniles, and calves was 1:0.2:0.1. A suitable elephant habitat was determined to be 1,288.9 km2 using Area Under the Curve (AUC). An AUC = 0.061 indicated good performance. Our model classified habitat preferences associated with elevation, forests, salt licks, human activity, and slope. Conclusions According to our probability map this sanctuary can provide a suitable habitat for elephants. Our results indicate that effective management practices can protect wild Asian elephants in the region and reduce conflict between humans and elephants.

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