The work begins

Every time I go back to the Annamites I’m surprised by just how tough it is to work in this landscape. It’s up one mountain and down another in terrain that would give a mountain goat vertigo. (That being said, there is a goat-like animal here called a serow that I will blog about in the future). This trip was no exception. It was hard to get back into the routine of things. This is the most physically demanding landscape I’ve ever worked in. But the rewards outweigh the difficulties. For a tropical ecologist there are few places in the world as spectacular as the Indochina moist broadleaf forests. It’s one of the most biologically intense places on the planet.

It didn’t take long to realize that for leeches we would have to stay close to the streams. To find animal sign it was best to work the mountains―but unfortunately these areas were very dry and leechless. In several hours of searching the ridgetops we found only four or five leeches. Even then, two of those were picked off our clothing, and I’m convinced that they were hitchhikers that had latched on when we were climbing through streamside vegetation. The fact that leeches were not found in the majority of the forested area was both unexpected and unfortunate. Our searches were limited to small areas and a specific microhabitat. But that’s the way fieldwork goes. You have to roll with the punches. But I hope this is an anomaly: If all sites that I survey this fall are this dry it will make it difficult to collect the large leech numbers needed to detect rare species.

Wet streamside vegetation
Wet streamside vegetation

At least we weren’t completely striking out. It took some effort, but we were finding leeches. Several people have asked me how exactly one goes about collecting terrestrial leeches. It’s surprisingly simple. Usually they find you. At a bare minimum the only requirement is a pulse. There are ways to improve your odds. If you can take a more proactive approach—overturning vegetation, looking through leaf piles, crawling on hands and knees in places that look particularly leechy (best not to think about venomous snakes when you’re doing this)—you can increase your success rate at least twofold. In fact, I’d say that most of the leeches I collect are on the ground or clinging to low hanging vegetation. I’ve also noticed that there seems to be some delay in leech reactions. It’s best to let one person travel ahead on the path and then have another follow slowly behind, scanning the ground for movement, ever on the lookout for inching ectoparasites.

These first days set the work schedule for the entire trip. Wake up early, hike along the mountain streams, find as many leeches as possible. Although I was disappointed that we couldn’t search the ridgetops it was gratifying to know that we were collecting samples in a good location and making overall progress. It’s possible that there are more leeches on the mountains during the rainy season and I’d make a point of coming back then. But for now we’d do what we could. I kept reminding myself that every leech collected in these biodiverse and unexplored forests is valuable. Even if we didn’t get the sample size that we wanted, a small number of leeches, even a handful, could provide critical insights into the ecology of this region.

Mountain stream
Mountain stream
Dangerous terrain
Dangerous terrain



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