Dave Fletcher's Notes Susan Sprenke's Notes David Lesley's Notes

Susan Sprenke

Notes from a Clearing: La Selva, SOR 500

Introduction - La Selva Biological Station is a research site of over 1600 hectares containing a variety of environments, some of which are managed. Our team decided to do an observation of the natural history of a site in La Selva. My first site presented some difficulties and I decided to join my team member, Dave Fletcher at his site. Both sites were on the SOR trail in the northeast section of La Selva, 500 meters past the river station. My first site was the bridge on SOR at approximately 450 m and the final site chosen was the abandoned plantation at SOR 500. The abandoned plantation site had swamp to its south, a river to the east and north and primary forest to the west. There are two old buildings on this site and several small, decomposing outbuildings. The “house” is not maintained but is used by Project Saccopteryx, a bat project. The lawn around the buildings is cut and the grass is very low; however there are many trees, most of them large, growing in the lawn. The property sits on a small ridge, above the Puerto Vieja river. The river’s current is fast and the bank is eroded, although there are old steps leading down to what once may have been a docking site. Several large trees submerged in the water have created a calmer pool close to shore.

July 27: 10:30 am to 12:00 noon

The site I have chosen is a small bridge on the SOR trail passing over a very fast moving creek. The bridge is iron and the remnants of the old bridge are still standing next to it. The old bridge is so covered in moss and vines that I initially thought it was a tree hanging over the water. On the downstream side of the bridge is a large Cecropia tree. Two howler monkeys (Alouatta palliata) were in the tree, one significantly smaller than the other. The larger howler seemed very disturbed by my presence at the north end of the bridge. I was sitting slightly below the bridge, on the top of the creek bank next to the old bridge. The howler called out several times and finally threw sticks down in my area. When I got up and moved to the middle of the bridge, the behavior stopped. Both monkeys were tearing leaves off the tree and eating (bugs, larvae?) from the leaves. I moved back to the north side of the bridge. The ground was covered with some leaf litter and a rug of Selaginella. The underside of the old bridge was filled with ferns and seedlings. Around the bridge was a mini-forest of palms, all around 2 –3 meters high. Small brown moths disappeared when they landed on leaf litter and bright orange and yellow butterflies fluttered by completely exposed. All options seem taken in the rain forest. The howler monkeys became disturbed again and began urinating, howling and throwing litter. Again, moving to the middle of the bridge ended their display. I decided to change my site to the old plantation house site.

July 28: 5:20am to 10:30 am

5:20 am - I have decided to begin by sitting up on the bank of the river. The river is flowing quickly, but fish are jumping out of the water for bugs in the calm pool close to the curve in the shore. Behind me are two large canopy trees, Dipteryx and Cecropia. Up in the Cecropia are several howler monkeys. One of the monkeys begins a very loud howling which lasts for almost 15 minutes. The howling is answered by another howler monkey in a Cecropia behind me. This call and response takes place in the mist of early morning, with the sun just coming up over the edge of the trees on the far (east) bank of the river. What is the poem that has the line in it “to see heaven in a flower”? The greatness of poetry is its ability to find the perfect few words for huge emotional experiences.

The flies have discovered me.

The howlers are waking up and peeing in the river. A rain of urine is hitting the water. It is too easy and very wrong to anthropomorphize about primate behvior, but really. I wonder what the effect of monkey urine is on that little pool of quiet water. The river’s current still flows through it, but is really slowed down by the submerged trees. How does the urine change the chemistry of the water? If this is the morning protocol for this group of monkeys, the daily input might be substantial. The howlers are moving from the large trees to a circle of five smaller trees around it. The branches of the trees are waving quietly as they move. There is such a disconnect between seeing this great leaf movement but not feeling the wind you are expecting! The river bank has very little growth, it has been trampled by down to mud, probably by larger, bi-pedal primates, although some peccary tracks (Tayassu tajacu) are visible. There are twigs lying on the slope of the bank. They have not been trampled and have probably fallen off of the trees overhead. However, these twigs are covered in various amounts with moss and the smallest bromiliads I have seen yet. Have these twigs been lying undisturbed long enough for moss and bromiliads to grow, or do the moss and bromiliads grow that fast? Perhaps they were already covered when they fell off the trees, but if that is so, they fell very gently, for they are not damaged. The rain forest has so much that is large and a surprising number of organisms that are prefectly small.

The birds are calling. The birds calls I can distinguish are the loud, clearly defined calls. I can separate at least five, amidst the background noise of constant chirping. I have been here long enough to not presume that the birds matching the noises are large in size!

I think of the rain forest as growing up, trying for the canopy. But sitting on the river bank, I can see many plants growing down, using gravity as their director of operations. Mosses hang from tree branches, green hair in need of combing and roots from vines hang down to the ground for 10 meters and more. All directions are used for growth, there is no negative space in this ecosystem.

6:30 am - I have moved back up the hill, away from the river bank. Fletch is already here and this gives a better view of the trees holding the howler monkeys. I can hear monkey noises in the primary forest outside of the clearing. There is a lot of activity, with grunts and low-pitched shouting. A coconut fell out of the tree by the old plantation house. It was not ripe enough to split open and hit the ground with a solid thud. There is a large disturbance in the trees around us. The branches are whipped up, a silent storm passing from one tree to another until all the trees around us are waving up in the canopy. Monkeys are everywhere. Most are the same size, however some are juveniles, and a very small howler monkey is moving quickly to catch up. I see one monkey with a baby on her back. They are filling the trees above us and around us. Debris is hitting the ground along with urine and feces. And yet, there is no noise outside of the debris. The monkeys are not calling or making a sound. Some of the monkeys are coming down to lower branches, but they are maintaining a distance. I can count at least 20 monkeys and there are probably many more. I moved closer to the tree trunk to get away from anything falling. My tree (my new home!) has large bromiliads growing up the trunk and they give me a great sense of comfort-a natural umbrella. I can hear soft, chirpy noises from the monkeys. The movement in the trees continue, and the debris increases in speed and number. The monkeys are eating the figs from two large fig trees growing close to us. They spend almost 20-30 minutes moving and eating and all quiets down. I can see howlers clearly, beautiful golden brown fur when the sun is shining on them, and little ruffs around their faces.

7:30 am - There is more light in the clearing and the landscaping becomes apparent. The old house and the river bank are in circles of bright clear sunlight, while the lawn remains shaded.

The design must have been lovely when the underbrush was cleared to the river. A large broadbilled motmot is on the ground, beautiful orange head with long green tail. It is hunting bugs and moves leaves aside with deliberation. The soft grunting sounds of the peccaries can now be heard from the underbrush. Cicadas are very noisy and pulsing about 40 times per minute. The air temperature is 78 degrees F at 8:15 and 82 degrees by 8:30. The day is heating up quickly. Several people have passed through the clearing at different times during the morning and the large peccaries bark at one of them. I thought I was hearing a dog! A pack of peccaries is crossing the clearing and disappearing into the brush in the northeast corner. Mosquitoes, flies, and other small insects are coming around. A very large ant (bullet?) climbs on a tree root next to my leg. It is tossed away by Fletch. There have been no signs or sounds of monkey for a while. The decaying trees scattered in the clearing are sculpted by the mosses, ferns and bromeliads growing on them. They look almost carefully placed.

10:30 - The clearing has reached a stasis for the moment and we decide to leave.