- Camera-trap surveys in the Annamite mountain range between Laos and Vietnam have provided an overview of two incredibly rare and elusive mammals that occur nowhere else on the planet: the Annamite striped rabbit and Annamite dark muntjac.
- Understanding the distribution and habits of rare species is crucial to guide the development of effective conservation measures, the study authors say.
- The study found that Annamite dark muntjac are more likely to live in high-elevation forests, and in remote locations far from villages, while Annamite striped rabbits were found across a range of elevations throughout the region.
- Experts say snare removal will be key to securing the mammals’ long-term survival, and the results of the study will now help conservation managers to focus often limited resources on areas critical for biodiversity.
The Annamite Mountains are a series of jagged peaks and secluded valleys that run between Laos and Vietnam south to Cambodia’s northern plateau. Over the past three decades, researchers have described numerous new-to-science large mammals from the region, all of which occur nowhere else on the planet. However, biologists still lack basic knowledge about their ecology, behavior and distribution due to their extreme scarcity.
Now, an international team of scientists has completed a painstaking camera-trap study that provides insights into two of these elusive mammals: the Annamite striped rabbit (Nesolagus timminsi), and the Annamite dark muntjac species complex, a group of closely related deer species indistinguishable in the field. The team published its results in Conservation Science and Practice.
The study is the first landscape-scale overview of where these two animals live in Laos and Vietnam. It also provides crucial information to guide the development of effective conservation strategies to ensure their long-term survival, say the researchers.
“The factors influencing species distribution in the Annamite Mountains are complex,” said Thanh Van Nguyen, a doctoral candidate at the Leibniz Institute for Zoo and Wildlife Research in Germany and lead author of the study. “Through this study, we could assess how these factors influenced the occurrence of [the two] species across several study sites, and thus improve our understanding.”
Mysterious species
Although first described as recently as 2000, the Annamite striped rabbit’s population is believed to have halved since 2008, spurring conservation experts to list it as endangered on the IUCN Red List.
Wild encounters are rare, but Thanh said he was lucky enough to spot one of the dark-striped, rusty-rumped lagomorphs snooping around his team’s campsite one evening during fieldwork for the new study. He said he was surprised to see such a rare and enigmatic species in such a mundane setting. “I followed the sound … and saw a small, striped rabbit standing and looking back at me,” he said. “I was frozen … I just stood and looked back at it.”
The Annamite dark muntjac species complex is known to comprise Roosevelt’s muntjac (Muntiacus rooseveltorum) and the Annamite muntjac (Muntiacus truongsonensis), but taxonomists say further species could yet be discovered. So little is known about them that the group is listed as “data deficient” by the IUCN. Besides their dusky fur, Annamite dark muntjacs can be distinguished from other small deer by their tiny fangs and a small tuft of hair between their ears.
Camera traps indicate distributions
To find out more about these obscure animals, between 2014 and 2019 Thanh and his colleagues deployed 368 camera traps in systematic grids across six separate study sites throughout the Annamite Mountains. They focused on locations within national parks and nature reserves in Vietnam, but also looked at unprotected forests in parts of Laos.
The fieldwork involved trekking through forested hillsides to an elevation of 1,800 meters (5,900 feet). Negotiating the steep and narrow terrain in Pu Mat National Park in northern Vietnam was a particular challenge that necessitated weeks of wild camping to set up just a few camera traps, according to Thanh.
By the end of the survey, they had collected data from more than 43,400 camera trap nights, amassing 110 detections of Annamite dark muntjacs and 173 of Annamite striped rabbits. They then used mathematical models to create distribution maps and to investigate how the two species are affected by elevation and indicators of hunting pressure, such as remoteness and proximity to villages.
The team found that dark muntjacs were more likely to live in high-elevation forests and were more numerous in remote locations far from human settlements, suggesting that hunting pressure might influence distribution. On the other hand, the team found no obvious patterns for the Annamite striped rabbit. They were photographed at a variety of different altitudes across the study sites, and were not influenced by hunting pressure.
The Annamite striped rabbit’s seemingly random distribution might be explained by the presence of highly variable microclimates created by the rugged Annamite landscape, according to the study. For instance, the Annamite striped rabbit is thought to favor wet evergreen forests, which could be the reason that rabbits were observed only at lower elevations in northern sites, where high-elevation summit forests might be too cold.
Snare removal is key
Data from the study will now serve as a baseline against which to monitor future population trends of these two rare and elusive mammals, say the researchers. In addition, distribution maps will help conservation managers to focus often limited resources on areas critical for biodiversity. This could prove particularly useful to reduce snaring pressure — a major threat to mammals throughout the region, and a contributory factor in Annamite striped rabbit and muntjac population declines.
According to a 2020 WWF report, an estimated 12 million snares lie in wait throughout protected areas in Cambodia, Laos and Vietnam. Although hunters trying to catch bushmeat might not be targeting threatened species, the sheer number of snares set in some areas of the Annamites heightens the chances of some rare animals being caught incidentally, according to Thanh.
The researchers recommend the use of standardized snare removal protocols across protected areas in the Annamites to help identify hunting hotspots and trends across the region. One such method is the Spatial Monitoring and Reporting Tool (SMART), which is implemented at one of the study sites, the Saola Nature Reserves in central Vietnam. Over the past decade, ranger patrol teams have removed more than 110,000 individual wire snares from the reserves.
The new camera-trapping study confirmed that these snare-removal efforts are working: a sizeable population of Annamite striped rabbits was recorded in the Saola Nature Reserves. This is a “promising first sign” that conservation action is paying off, said Anh Quang Hoa Nguyen, study co-author and Annamite landscape species coordinator at WWF-Vietnam.
We “look forward to using this information to help protect these species as well as other key species that make the biodiversity in this part of the world so unique,” he said.
Citation:
Nguyen, T. V., Wilting, A., Niedballa, J., Nguyen, A., Rawson, B. M., Nguyen, A. Q., … Tilker, A. (2022). Getting the big picture: Landscape‐scale occupancy patterns of two Annamite endemics among multiple protected areas. Conservation Science and Practice, 4(3). doi:10.1111/csp2.620
Carolyn Cowan is a staff writer for Mongabay. Follow her on Twitter @CarolynCowan11
Editor’s note: This story was supported by XPRIZE Rainforest as part of their five-year competition to enhance understanding of the rainforest ecosystem. In respect to Mongabay’s policy on editorial independence, XPRIZE Rainforest does not have any right to assign, review, or edit any content published with their support.
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