474 L. J. Hale et al.


FIG. 1 Positions of camera traps within the Cangyuan section (core zone) of Nangunhe National Nature Reserve, south of Lincang Prefecture, China. The six cameras at which elephants were detected are numbered (see text for details).


on either habitat associations (Feng et al., 2010) or were part of national assessments of population size (e.g. Zhang et al., 2015). The elephant population in Nangunhe is regarded as genetically distinct, despite a small estimated population size of 20–23 individuals in 2014, with the highest nucleotide and mitochondrial haplotype diversity of China’s elephant populations (Zhang et al., 2015). The importance of the Nangunhe population for elephant conservation in China, and the region more generally, is therefore potentially sig- nificant. Here, we aim to provide insights that could im- prove conservation of Asian elephants, offering support for a metapopulation management approach.


Study area


Nangunhe National Nature Reserve is a 708 km2 national protected area located in the south of Lincang Prefecture (Bohnett et al., 2015). It lies within the south-westmonsoon climate zone and supports bamboo forest, monsoon ever- green broadleaved forest, seasonal rainforest, shrubland and tall grassland (Liu et al., 2016). The reserve includes an 85.3 km2 core zone, 89.4 km2 buffer zone and 101.8 km2 experimental zone within Cangyuan county, with the remaining 431.5 km2 in Gengma county. Elephants are restricted to the section of the reserve in Cangyuan county, predominantly utilizing the core zone in the west (Fig. 1), which experiences minimal human disturbance (Yunnan Forestry Administration, unpubl. data). The reserve is


isolated from other forested protected areas supporting elephant populations in China as the human-dominated landscape prevents elephant movement between fragments.


Methods


A total of 36 motion-triggered camera traps (26 Onick AM-999, Wuhan, China; eight Ltl Acorn 6210, Shenzhen, China; two ScoutGuard SG560 K, Molendinar, Australia), with infra-red illumination, were placed over a 44 km2 area within the core zone of the reserve to determine elephant population size, density and social structure (Fig. 1). The cameras were active for 47 days during May–July 2017 (the rainy season), although not all cameras were continually operational over the entire period, giving 1,394 trap days. The reserve manager advised that elephants predominant- ly use the core zone because the surrounding buffer and experimental zones contain steep slopes, farmlands, roads andsettlements.Tomaximize detectability,cameras were installed along known elephant trails at c. 1-km intervals, across all vegetation types. Cameras were set at a height of 1.5 m, at a focal distance of c. 5 m (Varma et al., 2006). Cameras were directed either north or south to avoid sun glare and any overhanging vegetation was cleared to prevent false triggers. One camera was set per station, which were set in positionswhere the angle of viewwas along trails,withlittle potential for movement outside the camera’s field of view. Cameras were configured to take three photographs and 10


Oryx, 2021, 55(3), 473–478 © The Author(s), 2020. Published by Cambridge University Press on behalf of Fauna & Flora International doi:10.1017/S0030605319000504


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