California Academy of Sciences
The campsite . Photo by Angus Gascoigne.
Trig point on top of Pico (to prove we were there!) Photo by Angus Gascoigne.
Ricka frog hunting on top of Pico. Photo by Angus Gascoigne.
Leptopelis at campsite. Photo by Angus Gascoigne.
Sarah, Ricka and Manonu with dinner (Archachatina bicarinata) on top of Pico do Principe Photo by Angus Gascoigne
Wet shoes in the morning. Photo by Angus Gascoigne.

A Visit to Pico do Príncipe
Dispatch Number Ten - May 17, 2001
Text by Sarah Spaulding, Invertebrate Zoology & Geology


Early this morning, Ricka and I organize our backpacks for a trip to the Pico do Príncipe, the highest point at under 1000 meters elevation. Príncipe has several dramatic "picos", volcanic plugs of vertical rock rising out of the primary forest. Pico do Príncipe is one of the peaks that can be climbed by ordinary humans, and on our climb we will have the opportunity to examine changes in species distributions with changes in elevation.

On this trip, I will collect diatoms (microscopic algae) from the streams and forest pools. The freshwater habitats on Príncipe differ from those that I have observed on São Tomé, where I can see and feel the diatoms growing on rock surfaces. Here in Príncipe, the high gradient (steep) streams are clear and tumble over rocks, without a trace of diatom "slime". Does the geomorphology limit the diatom flora here?

We have two guides, Angus Gascoigne and Mununo. Angus works in São Tomé, and has a long-standing interest in the biodiversity of the Gulf of Guinea islands. He is graciously acting as a guide and Portugese translator for this trip to Príncipe. Mununo grew up in the forests of Príncipe; walking, hunting, farming, and gathering abundant things to eat. We knew that Mununo had guided Jonathan Baillie on his trip over some of the same terrain a couple of years ago.

Our packs are filled with collecting gear and the food we could round up at the local market: cajacha manga, pineapple, banana, crackers, biscuits, and tins of canned meat products (a counterpart to Spam). We set out from the old plantation of Sao Joaquim, after waiting for high winds to subside. The rain comes, but at least we won´t have to worry about trees falling on us.

The ascent to our camp wanders through cacao, banana, coffee, and oil palm plantations. We cross the Rio Banzu, and the plantations become increasingly abandoned. Mununo leads the way, clearing a path with his machete, and marking the trees so we will be able to find our way on the return. We stop to eat a fallen jackfruit on the way. It is an odd-looking fruit to my eyes, about the size and shape of an overinflated rugby ball, but is sweet and chewy.

I am amazed at the slopes that Mununo leads us up, backpacks and all. We climb steep, slippery mud slopes that are covered with rotting leaves. Ricka and I lunge for roots and small trees with great faith, and hope that we don´t slip and slide down the slope to the bottom.

As we hike through this dripping wet forest, I think about this tiny oceanic island, and how these forests did not always exist here. This island first emerged from the sea as a lifeless chunk of volcanic rock. Last week, when Ricka and I surveyed the rivers of south western São Tomé, we walked on the black volcanic rock of the coastline. In the hot equatorial sun, it was an extreme environment.
Inhospitable and severe, the sort of place I would not be able to survive for very long with this human body. I imagine that when organisms first landed on these islands, the conditions would have been extreme. Of the terrestrial organisms that survived an ocean crossing, some survived, but most did not. The organisms that were able to colonize initially, actually changed the island by their very presence. Now I am in the midst of a forest with many endemic species, whose ancestors all arrived in some manner on this isolated place. As I walk, I stop to look for the distinctive yellowish brown of the chlorophyll of diatoms. I collect tiny bits of material off the rocks in the streams, forest pools, and mosses and record each location with the objective of determining what species made it here and whether they evolved into unique forms in island isolation.

We make our camp on a small ridge near the headwaters of the Ribeira das Agulahs, at 600 m elevation. Our tents are in the midst of tree ferns and flowering plants. We eat our crackers and fruit and tins of meat (mmm). I am tired and ready to rest at camp, but Ricka´s work is just beginning. She waits for dark, and then sets out with her headlamp to the stream to listen and look for tree frogs. She is gone for a long time, Angus keeps an eye out for the bobbing of her headlamp in the dark forest. We figure she must be finding lots of frogs, she is gone for so long.

In the morning we begin the climb to the summit. The vegetation continues to change as we gain elevation. More and more species of ferns appear, and the tall forest trees are replaced by smaller, thinner forms and the forest seems somehow brighter and drier. Angus is on the lookout for ferns, and spots an endemic fern that was last collected in 1956, Grammitis nigrocincta. Alston. He has also been interested in snails of the islands - we see sparkly golden shelled species, a carnivorous (pink!) snail in a clear shell, and he is on the lookout for another endemic, Thyrophorella thomensis, an unusual operculate snail. It has what looks like a trapdoor covering the opening to its shell.

We gain the summit block, a narrow couple of meters across. I prefer to stay close to the center, a bit nervous that the vegetation around the summit could give way. The clouds have closed in, but I can feel an updraft of air coming up the face of the pico. Maybe it is a good thing I cannot see the abyss below. We eat crackers and tinned meat (actually, I skip the meat after getting sick on the funny tuna last night). And, here on the summit, Ricka finds a frog! Mununo pulled the shells off some 20 of the huge endemic snails that he has been gathering for tomorrows's dinner. The smaller ones are the size of my fist.

Back at camp, Ricka goes out for another nighttime survey. It begins to rain, coming down hard most of the night. My shoes were throughly soaked from the previous day, so it did not seem to matter that they had an inch of water sitting in them in the morning. We finally make a mad dash to pack our soaked gear into our soaked packs and carry them on our instantly soaked backs. The streams and rivers have all swollen with the heavy rain, and it makes for exciting stream crossings. I am thinking of the Rio Banzu, "will we be able to cross it?". But Mununo sees plastic jugs high in the palms, placed there to tap the fizzy sweet sap of palm wine, and knows that at least one person has been able to cross the river this morning. The water is high, with a swift current that rides above mid thigh. It doesn't seem to bother Ricka or Angus much, they both have smiles on their faces as they cross.



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