Today we learned a valuable lesson in analyzing data. Statistics can help or hinder you and you must consider your question carefully to decide what kind of analysis to use. Different tests can give you different results, so you must be careful in considering your community and think about what will give you the most scientifically meaningful results.
After several lectures we took a short night hike and found spiders, cockroaches, insects and some people even saw a coral snake. The dry season has been particularly harsh and there is not much moisture, so I didn’t see any amphibians last night. They are probably hiding deep in the forest under the leaf litter or in other damp places.
Life in the canopy is very different from life on the forest floor. There are differences in water, sunlight, vegetation, other organisms, the affects of gravity and access to food and nutrition. Nitrogen is an important nutrient and decomposers on the forest floor are essential parts of the nitrogen cycle. With this in mind we hypothesized that the forest floor would be more nitrogen rich than the canopy. Specifically, that arthropods in the canopy are more nitrogen limited. We tested this using pitfall traps both in the trees and in the ground. We used control traps filled with water and traps full of nitrogen-rich liquid (our own urine). Tomorrow when we collect the traps we expect to find more arthropods in the urine filled traps, and more arthropods in the tree traps than the ground traps.
This afternoon we went spelunking in a cave at Las Cuevas that was used as a ceremonial chamber by the ancient Mayans. The Mayans believed that caves were entrances to the underworld and that at the end of the day the sun turned into a jaguar and entered hell through a cave to battle demons all night until it reached the other side. This cave had nine bottlenecks that represented the nine layers of a hell a Mayan hero fought through in their mythology. We belly-crawled through the mud-guano cave floor to several hard to reach spots. There are many Mayan artifacts in the cave and areas are still being excavated by archaeologists. We found a lot of pottery, but also a human femur and an animal skeleton. Most excitingly, we saw wrinkle-faced bats roosting. Other animal sightings included glow worms and whip scorpions. Of course the formations are almost alive themselves, with huge chambers swallowing you up.
I have been searching for amphibians in damp areas like the cave entrance and inside bromeliads but I haven’t had any luck today. The leaf litter can also shelter cryptic amphibians, like toads, but I haven’t found any so far.
Today we focused on some of the many ant species that habitate the Chiquibul forest. The cecropia tree has a symbiosis with azteca ants, which protect the tree from predators in exchange for shelter and food. We spent the morning testing a few hypothesis about how the cecropia trees avoid herbivores before they are colonized by the protector ants.
This afternoon we excavated three leaf cutter ant colonies of different maturities. Once a queen colonizes a nest after a nuptial flight she can live for 20 years reproducing, expanding the colony until there are millions of ants at any given time. There are tunnels underground leading to chambers full of the ant’s fungus garden and pupae. The youngest ones are fairly small, but once they are 10 years old they get huge, with tunnels the width of your arm full of soldier ants ready to come out and attack you when you disturb them. They have quite a pinch and we were all thankful for our rubber boots today.
We had an unexpected amphibian sighting once we got back to our housing; one of the bedrooms had a large frog on a bedpost. I caught it and took it outside to get a closer look and try to identify it. It hiccuped in my hand, puffing out its chest, in protest to its capture. The frog was dark green and brown, with some stripy markings around the forelegs. I couldn’t examine its back without it jumping from my hands so I didn’t get a clear look. It was about 2.5 inches long with horizontal pupils, bronze irises and toe pads. The toe pads indicate that its a treefrog and since there aren’t many in the area I would have to guess that it was another common Mexican treefrog, based on size and color. I released it into the trees after a minute or two to not cause it too much distressed and it leapt from my hands with a defiant squeak.
Today we completed our journey south-west through Cayo and into the Chiquibul rainforest. On our way to our home camp at Las Cuevas Research Station we took an anthropological detour through Mayan ruins. We were guided through the Caracol Archeological site and climbed up and in and down the ruins and tombs. Even though it was mostly overgrown and covered by years of sediment the pyramidal structures still stood and it was easy to image the bustling metropolis it was 2000 years ago. Hearing about the (hypothesized) reasons for its decline was ominous; overpopulation, agricultural collapse, drought… sound familiar?
Even though its citizens are long gone the city is still full of life. Almost everyone found an animal from their taxonomic group—bromeliads, philodendrons, birds, mammals, and a plethora of plants. The highlights included an edible red fruit (you suck on the seeds but don’t eat them, looks like gunk, tastes like papaya), toucans, a coati and a blue crowned mot-mot.
Sadly there were not any amphibians around for me to identify. The area was much too dry to be a suitable habitat. Amphibians require a damp habitat because they experience high evaporative water loss through their skin. Most also require water for reproduction. Caracal was in the forest but it was not dense enough to retain the moisture necessary for most amphibians. Here in the forest surrounding Las Cuevas should be a much more habitable medium and we can expect to see a variety of species in the next few days.
As per usual, something went wrong with the van. Our original plan for the day was to leave Las Cuevas early in the morning in order to make it to ATM cave for a swim and exploration. Then, we were going to drive across Belize to stay at the zoo. This is not how our day went at all.
Most of the morning was spent sitting on the porch, waiting for our van to show up. This went on for several hours. Rather than spend all our time waiting, we got the opportunity to tour other parts of the Las Cuevas research station and learn about their ongoing projects.
When our van finally arrived, we all climbed gratefully into its semi-air-conditioned space. Unfortunately, our massive time delay prevented us from being able to visit the ATM cave.
However, we did end up going on the night tour of the Belize zoo. Not only did we get to see two of the eighteen jaguars that they have, but we got to see margays, ocelots (so noisy), two types of owls (Rice!), a tapir, and three kinds of snakes.
Overall, I remain optimistic about the rest of the trip. Each thing that goes wrong does not faze our group at all. The new challenges that the reef will pose to us will be just new bonding experiences for us.
On our last day at the Las Cuevas Research station, we spent most the morning and afternoon retracing our steps from the first day. All of this was in the effort to understand if species richness differed between natural and man-made clearings. I am proud to say that the hike was not nearly as exhausting as it was at the beginning. I also got the change to see an example of epiphytic Encyclia cochleata, the national flower of Belize. I think I have achieved my peak of epiphyte. It was one of the most satisfying moments of this trip to date.
After cleaning up and showering we went over to the classroom for taxonomic presentations, my presentation on NTDs/ethnobotany, and to look at what our camera traps caught. I really enjoyed my topic, especially because I had taken a research seminar in the previous semester on the topic. We then got into an interesting discussion on how Brazil should manage the threat of Zika and the upcoming influx of people for the Rio de Janiero Olympics.
Our pictures from the camera trapping experiment were a bit disappointing until we got the last one. On its memory card, we found both and ocelot and a WHAT WAS THIS. Overall, our data set was way to small to be able to really tell anything about the preferences of animals in the Chiquibul for man-made or natural clearings. All in all, these past experiment (while they don’t yield statistically significant data) are doing a great job of showing me how to trouble shoot ecological/evolutionary experiments.
Today was not a great day for epiphytes. This isn’t because they weren’t out there, but just because we spent most of the day inside. Our main project was to interpret the results of our pitfall traps. After collecting the vials, we headed back to the classroom to assess the morphospecies found. Our hypotheses focused on whether species abundance and richness were different in the canopy versus the forest floor and whether or not canopy species were more attracted to a nitrogen source (our urine).
The first question was more straightforward than the second. We could clearly see that both abundance and richness were greater for the forest floor. However, teasing apart the question of nitrogen limitation in the canopy versus the forest floor proved to be much more complicated. In the end, we choose to represent the difference between the by creating data points by subtracting the amount of arthropods in the water from the urine (for canopy and ground). Upon discussing the report with Scott and Adrienne, we found many ways in which our work could be improved upon. Two of the most crucial changes we made was to use a proportion rather than a subtraction and to pool all samples we took (broadening our community). This refining process is both interesting and productive; many new research directions came from our discussion.
At the end of the day, we all went on a night hike. The difference in number of species we saw was really noticeable. As for epiphytes, I certainly saw them, but am becoming more and more convinced that this group is hard to pin down for any specific geographical location. So many of the factors of what species ends up where is tied to the specific characteristics of the niches of the Chiquibul forest. In the future, I would be interested took look into the literature for information on niche exploitation by epiphytes. I think it would greatly increase my comprehension of the epiphyte landscape.
For our second to last day at Las Cuevas, we wrapped up our arthropod experiment by collecting all the pitfall traps set along the Maya trail yesterday. The majority of the day was dedicated to data analysis and the presentation of our results; there’s nothing quite like having a poster session in the middle of the rainforest.
We also spent a good part of the day discussing illegal extraction from the Chiquibul and the problems with conservation in Belize. I never fully appreciated the intricacies of conservation biology until today. The Chiquibul’s greatest threat is illegal extraction of plants and animals by Guatemalans from villages along the nearby border. Yet the issue of conservation is much greater than that of sustaining the area’s ecology and incorporates complex economic and political landscapes, as well.
Central American coral snake (Micrurus nigrocinctus).Central American coral snake (Micrurus nigrocinctus).
Since our activities were primarily indoors, the day offered few opportunities for reptile sightings. However, I was excited at the prospect of our first night hike—the evening brings out a number of nocturnal species, transforming the Chiquibul into a completely different habitat than it is during the day. We managed to spot all kinds of creepy crawlies, including spiders the size of your face and a giant roach that emitted a sticky white substance. By the end of the hike, I had nearly given up on searching for reptiles in the leaf-litter and under fallen logs. But at the very end of the trail, we approached a sinkhole; as I peered down I heard a shout of “snaaaake!” I looked down to find the distinctive tri-color banded pattern of the Central American coral snake (Micrurus nigrocinctus) all but a foot away from my boot. The snake was small but could clearly be identified as one of the most venomous snakes found in Central America. Just goes to show that you can never stop looking.
I never truly appreciated the feeling of being clean until today. There’s one thing about coming back hot and sweaty after a hike, but it’s quite a different feeling returning from an afternoon of spelunking covered in a fine mixture of mud and bat guano.
View from inside Las Cuevas cave.Wrinkle-faced bat inside Las Cuevas cave.
But let’s backtrack. Today’s tasks began relatively lightly by wrapping up our (inconclusive) cecropia experiments. The day’s primary activity was the exploration of the cave from which Las Cuevas gets its name (and water). The 9-chambered cave is the center of an ancient Mayan ceremonial site, with each of the rooms representing one of the nine layers of the Mayan underworld. The cave holds numerous Mayan structures and pottery, and even what appeared to be a human femur. I doubt I’ll be picking up spelunking for recreation anytime soon, but our exploration gave me a newfound appreciation for cave biology. We found two species of bats within the cave system, as we crawled on hands and knees through narrow passageways that opened into large caverns. I thought I was clean until the cave’s final test: a tiny chamber with low oxygen content, housing a peccary skeleton. Let’s just say I was in great need of a hot bath after that adventure.
Finally, we set up an experiment to test nitrogen deficiency in arthropods of the rainforest canopy. Once again, we utilized extremely sophisticated technologies to create pitfall traps for arthropods in the canopy and forest floor, taking advantage of our most accessible nitrogen source: urine. I was thankfully spared from urine collection, but the afternoon was dedicated to setting up pitfall traps along the Maya trail (not named after yours truly). Though there were no sightings today, the leaf-litter our traps were set in are a prime habitat for venomous snakes; the forest floor was thoroughly checked for species like the yellow-jawed tommygoff (Bothrops asper) before setting traps. I did however spot several anole species along the Maya trail, all of which moved too quickly to be identified.
All in all, day 5 of EBIO 319 is best summed up by the following statement by Dr. Scott Solomon, “We’re exploring the mammalian excretory system!”
Today’s task seemed simple: form a hypothesis and set up 12 camera traps in the forest surrounding LCRS.
Twelve hours later, our work is finally complete, but it was much easier said than done. After a 5:30am birdwatching session and a hot cup of tea, we set off to develop our experiment. We opted to test the impact of human pathways on local species richness and composition in the Chiquibul by setting up camera traps along roads and trails, as well as in natural clearings. In five days, we’ll collect these traps and see what diverse organisms they’ve managed to catch on film.
The morning’s hike seemed manageable on a map, but many hours and some (incredible) scarlet macaw sightings later, we had set up only half of our traps. By our 3pm lunch break, I had walked 7.8 miles or 16, 652 steps. Talk about a morning workout.
View from Bird Tower near LCRS.
Right before lunch, we ended our work at the Las Cuevas Bird Tower. The rickety tower stands at over 600 m of elevation, and the view is almost worth the steep hike up. (Note to entrepreneurs: the Bird Tower would be an ideal location for opening an ice cream stand).
Sumichrast’s skink (Eumeces sumichrasti).
Despite sweat and blisters, we loaded up on lunch and set off on the Monkey Tail Trail to install the remaining traps in clearings and a natural stream. The main reptile for today was the Sumichrast’s skink (Eumeces sumichrasti), an orange and black lizard with a bright blue tail. I saw evolution in action when we caught a blue-tailed skink; the lizard quickly shed its skin and darted off, leaving the wriggling blue tail in our palms (and the rest of the animal out of sight).
With our twelfth and final camera trap set in a mud wallow for a prospective tapir sighting, we finally trudged our way home. Though we were all exhausted and covered in sweat (and ticks, in some cases), I found somepeace in the pitch black of the forest. The trees of the canopy arched over the trail to form a tunnel, just like the trees at home on University Boulevard. And just as the blinking lights of the city lead me home at Rice, the twinkling eyes of spiders lit up the trail with pinpricks of yellow light, finally leading us back to Las Cuevas.
