FIELDWORK

(Note:  The fieldwork was developed by our TinkFrog leaders)

Tree Measurement

Data Analysis

HABITAT DESCRIPTION

Background/Purpose: Ecologists and conservation biologists frequently need to know how a community of organisms is structured, such as, the species that compose the community; the abundance of each species; interactions of the species; and, the increase or decrease in species over time.  The information may be used to develop conservation plans for natural areas or recovery plans for threatened or endangered species.
Field exercise: We measured habitat characteristics relevant to monkeys @ El Zota, comparing a portion of secondary forest to a portion of Gmelina plantation.  In each forest habitat, we collected various data on trees within a set plot of land. This type of sampling is called the "Belt Transect" method.  After our collection areas were measured (three 8 X 10 m sections) and plotted, each tree within the area was labeled and marked. Next, we collected the following data related to each tree: range of height; estimated age of leaves; circumference; and, presence of lianas, flowers, or fruit.  Finally, group data was graphed and analyzed.

Conclusion: We actually came up with more questions than were answered with our data and found that given the diversity of tropical rain forests, it is difficult to use sample study areas to make generalizations regarding larger areas.  Since new habitats and new species can be found as a sampling area increases in size, research should be focused on a particular species composition and abundance from a sample in a particular study area or from a particular habitat type within it.
 

Hummingbird visits a Heliconia plant

POLLINATION ECOLOGY: 
CO-EVOLUTION AND NECTAR FEEDING

Purpose/Background: It has been noticed that a wilting of the Heliconia flower occurs following a visit from a hummingbird. Our task was to determine the relationship of time between the amount of time spent at each flower and when the flower wilts.
Field exercise: First, we chose a particular type of Heliconia plant (Heliconia tortuosa) and then predicted the type of hummingbird (Rufous-tailed Hummingbird (Amazilia tzacatl)) that we would expect to find at this plant type, based primarily on flower structure and the bird's beak shape. Next, we located our plant subject and set up an observation post.   During the observations, we sat about 4m away from our focal plant. We predicted that pollinating visits involved the probing of the flower through the opening of the corolla, and probably involved contact with the reproductive parts of the flower.
Conclusion: While our observed hummingbird visits did not appear to involve nectar consumption and were unlikely to result in pollination, we concluded that the flower must be opened in a certain position in order for the process to occur.  We also learned that hummingbirds have a different size and shaped beak that are perfectly suited to the size and shape of the flower that they feed on.  It is believed that the bird and plant have co-evolved together in order to match each others needs. The flower provides nectar which feeds the bird, and the bird serves the plant via pollination.

Pit Fall Trap

INSECT BIODIVERSITY STUDY I

Purpose/Background:  While the rain forest is filled with a variety of trees, the plantain plantation lacks the same diversity of plant species. It is this lack of diversity that can impact other biodiversity in an area.  In addition, "allopatric speciation" may result due to biological populations being physically isolated, resulting in negative impacts This study was intended to compare insect diversity found in the plantain forest to that found in the secondary rain forest.

Field exercise:  Using the same belt transect method from the habitat study, we plotted our areas in the plantain forest.  We then buried plastic cups so that the opening was ground level.  After pouring a small amount of alcohol in each cup, we covered the opening with leaves for camouflage. The next day, we collect our samples; separated differing species of insects; and, counted each species.

Conclusion:  We expected to find a larger variety of insect species in the rain forest since it is home to such a wide variety of plants; however, our data revealed the opposite when compared to the other groups.  Our findings led us to question whether the position of the study area with respect to the trails vs. the road might impact results.  In addition, we concluded that it would be necessary to increase the study areas in both cases in order to consider the results valid.

Collection of Specimens

Spider Found on Trail

INSECT BIODIVERSITY STUDY II

Purpose/Background:  (See Insect Biodiversity Study I)

Field exercise: Our areas were plotted using the belt transect method. A net was used in a sweeping motion to capture insects within the plotted area.  In addition, we were allowed to collect other species of living organisms found on the trail, within the plot. A butterfly net was set up to collect samplings of those species within the area.  Note: All collections were obtained using safe methods for the species and all were returned to their original area following the lab analysis.

Conclusion: The activity provided us an opportunity to make closer observations of a considerable amount of species. We challenged ourselves to explore the area in closer detail in order to discover things that we may not have noticed before. In fact, LeeAnn found and captured an amazing spider that was voted "most interesting catch" by the other groups. The unidentified spider had a green body with orange legs. Other collections included a variety of tree frogs, lizards, millipedes, and much more!

GREAT GREEN MACAW STUDY

Purpose/Background:  The population of the Great Green Macaw is in great danger of becoming extinct in Costa Rica. Here it is estimated that less than 200 individual birds remain.  There are no known pairs nesting in El Zota.  Biologically, the Great Green Macaw is used as an indicator species of forest health. Where macaws remain the forest is relatively healthy. By protecting habitat for the macaw, habitat will also be protected for thousands of other species of creatures that live in the same habitat. The Almendro is a tree that produces a large almond nut that is food for the macaw. The majority of macaw nests are in Almendros, and they also get water from the trees in smaller cavities where rainwater collects. These same Almendros are being cut from the forests.

Field exercise: Isreal, who was our guide, is currently conducting research on the Great Green Macaw to try in order to determine why the macaws are no longer nesting at El Zota. Our participation involved a lengthy hike to identify, mark, and measure any Almenro trees along our path. We were also instructed to record any potential sitings of the macaw.

Conclusion:  We saw no macaws during our hike and found only a few Almendros. We did experience an exciting siting of a Great Green Macaw pair. Interestingly, it was during our soccer game that was hosted by local residents. It was an amazing moment! The above video captured the brief encounter.

Leaf Cutters at Work

 LEAF-CUTTER ANT HERBIVORY PROJECT

Purpose/Background:  Naturalist E.O. Wilson speaks of leaf-cutters as having perfectly evolved to address every small need necessary for their survival over their 50 million years in existence. These ants have long been a marvel to researchers due to their practice of sustainable agriculture. Other than humans, they are the only animal that grows their own food from plant matter. The ants cut leaves from plants and trees and grow fungus on these pieces of leaves.  They then use this fungus for their food.

Field exercise: After locating the entrance to a leaf-cutter nest, we set up group roles in order to collect our data. One pair recorded what every tenth ant was carrying (if anything) into the nest. Another pair was responsible for recording how many (if any) "hitchhikers" were present on each leaf that was being transported by the ants.

Conclusion: Different ants are responsible for each step in the production of fungi, according to their size. The jobs include defenders of the colony, caretakers of the young, gardeners, foragers and leaf-cutters. There are even tiny ants that ride on the backs of larger worker ants and defend them from predators. There is still much to be learned about these marvels, particularly with respect to the relationship between the ants and bacterium. 

Spider Monkey

Angry Capuchin

MONKEY BEHAVIOR

Observations:  Oh, where to begin?