Introduction

A remarkable place:

The Annamite Range, an isolated mountain chain straddling the Lao PDR―Vietnam border, is a global biodiversity hotspot containing some of the most intact and unexplored forests in Indochina. Two aspects make this ecoregion unlike any other on the planet: its high level of biological endemism and an unrivaled rate of recent discoveries. The large mammals in this region embody both aspects: in the past twenty years, several large mammal species have been discovered here. These discoveries include the Saola (Pseudoryx nghetinhensis), a ca. 85 kg (180 lb) primitive wild cattle species that was discovered in 1993 and remains one of the most elusive and enigmatic large mammals on the planet; the Large-antlered muntjac (Muntiacus vuquangensis), the largest known species of a characteristically small family of deer; the Annamite dark muntjac (Muntiacus truongsonensis), a secretive deer species that was only discovered in 1997 and according to locals lives only in the deepest forest; the Kha Nyou (Laonastes aenigmamus), or Laotian rock rat, a large rodent that belongs to a family that was thought to have died out 11 million years ago; and the Annamite Striped Rabbit (Nesolaus timminsi), a tiger-looking lagomorph who’s closest living relative lives in the dense forests of Sumatra several thousand miles away. In addition to these recently discovered species, this region holds other endemics, including Owston’s Civet (Chrotogale owstoni), a small black-banded insectivore, and red-shanked douc langur (Pygathrix nemaeus), which may hold the title for the most beautiful primate in the world. Other species that are both regional and global conservation priorities include tiger (Panthera tigris), leopard (Panthera pardus), clouded leopard (Neofelis nebulosa), two bear species (Ursus thibetanus and malayanus), elephant (Elphas maximus), and gaur (Bos gaurus). For a large mammal biologist, this is the place to be . . .

Elusive:

A major problem with studying any large mammal species living in tropical forests is that these species are difficult to detect. This is especially true in the Annamites, where densities are severely depressed from their historic levels due to high levels of poaching. Direct observations in dense forest habitat are rare, so to study these animals biologists have to rely on indirect methods. What kinds of methods do we use? There are a variety of options, each with its own unique set of advantages and disadvantages. The oldest technique, and the method used in the Annamites by local people, is to look for animal sign, notably tracks. A major advantage to using sign surveys to study mammals in the forest is that it doesn’t require fancy equipment or expensive analyses.  It is very cost effective. But the disadvantages are great. First, locating and reading animal sign is as much of an art as a science, and it can take years of practice to develop the expertise needed to identify animal tracks. In some situations it may not be possible, as is likely the case with the sympatric muntjac species living in the Annamites. Another problem is that in this region the rocky substrate makes a poor medium for leaving animal tracks: often the sign simply isn’t there to read. Biologists can also detect mammals by collecting their dung. With the advent of genomic sequencing techniques, it is possible to determine the species and even the individual the dung came from. A colleague of mine recently completed a survey of elephants in Cambodia using dung to identify the number of individuals in the area. One pitfall with using dung to conduct mammal surveys is that it degrades rapidly in wet tropical forests. In my experience, it is rare to come across dung in the Annamites, but this research technique should be explored more in the future. A relatively new invention, called the camera trap, has revolutionized noninvasive sampling, especially for elusive species. A camera trap is an automatic camera that takes a picture when a sensing mechanism is triggered. When an animal walks in front of the camera, the mechanism is triggered, and the camera takes a picture. It’s a great way to study mammals in tropical forests, and I will be using camera traps in my research this fall. (Stay tuned for pictures!) The major disadvantage, besides the fact that batteries have to be changed periodically, is that good camera trap units are expensive, upwards of 200 dollars US. Top of the line units may be 500 dollars. Setting dozens of units can be an expensive proposition. And then there are leeches . . .

Leeches:

Anyone who has spent time in the tropical forests of Asia knows that they are unique from the forests of Africa or the Neotropics in one significant and often annoying way: here we have leeches. No, not the aquatic leeches that most people think of when they picture bloodsucking ectoparasites, but terrestrial leeches that live in the forest. The idea of a jungle leech is difficult for many people to comprehend―at least it was for me. Imagine a long, wriggling, slimy worm-like creature with a suction-cup at one end (for holding on to prey) and a circular mouth full of razor-sharp teeth at the other (for piercing the skin of its host) that moves along the ground inch-worm-style searching for its next meal. Size varies, but usually the terrestrial leeches in the Annamites run between an inch and two inches, though I’ve come across a few that were, in leech terms, true giants. Leeches are so ubiquitous in the wet evergreen forests of Vietnam and Laos that locals rarely venture into the jungle without specially made leech socks. These socks are made from a burlap-material and are thick enough to deter attacks. Of course, one still has to pick off the leeches before they inch past the calf-length socks and onto your pant leg: once above the sock line, a large terrestrial leech will easily bite through khakis.  Perhaps one small consolation to anyone venturing into leech terrain is that the bite is painless. The flip side to this is that you often don’t know you have a leech on you until you happen to stumble across it, perhaps by brushing your hand against it. Many times I’ve woken up in the night thinking I didn’t know I had a mole there . . . only to find a quarter-sized leech so swollen with my blood that it looked like an over-filled water balloon on the point of bursting. In the jungles of Asia leeches are an ever-present reality. So why not use them to your advantage? That’s exactly what a group of biologists decided to do. In 2011, Dr. Tom Gilbert, of the University of Copenhagen, decided to test if mammals could be detected by sequencing the host blood found in terrestrial leeches. Nicholas Wilkinson, a fellow member of the Saola Working Group and Cambridge PhD student, collected 25 jungle leeches in the forests of central Vietnam and sent them to Dr. Gilbert’s lab. Surprisingly, 21 of the 25 leeches yielded amplifiable mammalian DNA. (For details see: Schnell, Ida Bærholm, et al. “Screening mammal biodiversity using DNA from leeches.” Current Biology 22.8 (2012): R262-R263.) The results showed that the leeches had fed on several common species, including pig and serow, but had also dined on some rare and elusive Annamite endemics, including Annamite striped rabbit and Annamite dark muntjac. And this from only 25 leeches! Notably, the Annamite striped rabbit had not been detected in over 200 nights of camera trapping effort in the survey area, indicating the power this method has for detecting rare species. Not surprisingly, these results caused quite a stir in the biological world: utilizing this new technique could revolutionize the way biodiversity surveys are conducted in the tropical forests of Asia. And that’s where I come in: I’ll be using terrestrial leeches to study the distribution and habitat preferences of the Annamites mammal community, specifically the little-known and elusive endemics. I’ll be spending the end of summer and the entire fall 2013 in Vietnam and Laos, conducting fieldwork in remote areas of the Annamites. I have a busy schedule planned, and I’ll use this blog to describe my experiences―the good, the bad, and the bloody―during that time. I’m excited: tromping through leech-infested jungles searching for rare mammals is more or less what I’ve always wanted to do, so I encourage you to follow me along on this journey. Until the next post, tam biet!

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