On his current expedition, Ronald Clouse ventures into the jungles of the Philippines to study harvestmen, or daddy-long-legs, of the order Opiliones. By collecting data for phylogenetic analysis, he hopes to learn more about the history of these creatures and the lands they inhabit.
After leaving Mt. Bulusan behind and reconvening in Manila, my colleague, Dave General (who I met up with in the last installment) and I flew to Davao City on the island of Mindanao. This island is home to the mysterious cyphophthalmid harvestman collected by Dr. Arvin Diesmos in 2009. We immediately liaised with Jayson Ibanez of the Philippine Eagle Foundation and, through his generous invitation and logistics, joined the USAID-funded biodiversity-survey team being run by PEF on Mt. Apo.
The climb up the slopes of Mt. Apo scores a “ten” for difficulty and discomfort… on a scale of one to five. Having hiked up a few mountains in this part of the world, I thought I had seen the worst of it, but Mt. Apo was on a whole new level, and the problem was the very soil that attracts so many farmers to its slopes. The slightest rain turns it to slippery mud that contains no rocks or big roots on which to walk, and few puddles to clean your feet. Moreover, there was no part of the hike that was easy; the more gentle slopes through farmland had no trees next to the path to grab for support, and the forest areas where one could find a sapling, root, or vine to hold were dangerously steep.
This all pertains only to Dave and me—the guides and porters raced up and down the mud like they were floating above it. Scenes to remember include standing for five minutes trying to decide exactly which slight depression in the bank might hold my weight (and choosing the wrong one, of course); watching my incredible guide, Leah, climb in mud, cut thorny ferns with a machete, and talk on her cell phone, all at once; and being passed on a nearly vertical slope in the rain by a porter carrying a generator on his shoulder. We were greeted at the camp by the cook, Liza Dans, and a hot cup of freshly brewed, home-grown coffee. The camp housed 46 workers who operated on a 24-hour schedule, marking and surveying transects to record flora and fauna. Our tents, which had passed us hours before, were already assembled on platforms cut into the slope, and Dave and I went right into the deep, soft leaf litter to hunt for harvestmen in the remaining light.
Here we encountered a mystery. The first sift of leaf litter revealed a forest that had been recently disturbed. We found Opiliones, and these are probably new species, but they were from more mobile families able to move in after logging or burning: Podoctidae, Epedanidae, and Assamidae. The next day Leah took Dave and me higher, and again we sifted what looked like good leaf litter, but after many hours we only found a single podoctid and a single epedanid. The mystery, though, was that we were also missing the weedy ants, which we’d expect to find if disturbance was the only issue. Perhaps at 1,400 meters above sea level we were simply too high to have much arthropod diversity in this region.
Climbing down after two days with specimens of the three families already mentioned, plus a single zalmoxid harvestman, Dave and I discussed what our observations meant. The forests appeared to have been recently disturbed, perhaps completely cleared once, perhaps still a source of building products and food. Around every wooded patch were current or abandoned farms and even a recently abandoned insurgency camp. The guides protected us from forest areas yet to be cleared of landmines, but there were other long-lasting effects of human activity. Camps and farms would have housed many people who would have continually extracted food and poles from the forests, as evidenced by things ranging from wild boar pits to tree stumps.
Many harvestmen can live at high elevations, with cyphophthalmids (“cyphos”) being found as high as 2,000 meters on Java. But the one on Mindanao was collected at only 400 meters, and not from very good forest. It’s very unlike cyphos not to be very picky, but it may make finding them a lot easier. The original locality is now off limits, slated for mining, but Dave and I are now trying our luck in the lowland areas of secondary forest around the region. Where will we find these elusive cyphos?
Video: Coming down from Mt. Apo, Mindanao; the community at 900-meters elevation.