Methods

Bat tents visible from the hiking trails at Las Cruces were surveyed in the Wilson Botanical Garden (Palm garden Trail), secondary growth forest (Jungle Trail, Rio Java Trail) and old growth forest (Rio Java Trail) on 7/31/99 to 8/01/99. Each area was searched for approximately 2.5 hours not including transient time. The Wilson Botanical Garden and the secondary growth forest was searched by seven group members. The old growth forest was searched by five group members.

The following data was collected: the number of plants with tents, the number of tents in each plant, the height of each tent measured from the ground to the peak of each tent, and the species type of each plant. We also noted the number of fronds per plant and whether the plants with tents were in clusters or in isolation. Tents were also checked for bats. All bats found were collected for identification. The collected data was statistically analyzed using the Chi square test and the ANOVA test. Microsoft Excel was used to perform the ANOVA test.
 
 

Results

The Botanical Garden had 28 bat tents in 14 trees. The secondary forest had 26 bat tents in 12 trees. The old growth forest had 5 bat tents in 3 trees (see table 1 and table 2). Analysis of the data collected for the number of trees with bat tents in each area lead to a significant statistical difference (C² =7.07,df = 2, p = 0.03). A very significant difference (C² = 16.51, df = 2, p < 0.001) was calculated for the number of bat tents found within each habitat. An ANOVA test also showed a significant variation in height among bat tents found in the three areas (F = 4.304251, df = 2, p = 0.018245) for height data see table 3. We found tents in 9 species of plants from 4 families (see table 3 and table 4). Of these plants, one species, Pinanga kuhlii, was introduced from Indonesia. This phenomenon may indicate that leaf structure and shape are more significant than the actual plant species.

A bat was netted in the botanical gardens. After analysis of this species it was determined to be an Artibeus watonsi. This caused some inquiry questions about the different bat species, in this area, which use and make bat tents.

 

Discussion

The destruction of an animal's habitat is a serious global issue. Researchers and scientists have been evaluating the effects of deforestation on many species throughout the world. One of the main questions concerns the impact of deforestation: are some animals more tolerant of global changes? Our findings tend to indicate that at least some frugivore bats are not limited in the successional areas.

In the botanical garden and the secondary growth forest many clusters of bat tents were found. This may be directly related to the higher density of broad leafed plants in these areas. Observation of the old growth forest revealed fewer broad leafed plants and thus fewer bat tents. On the other hand, old growth forests generally have more tree cavities. Bats may roost in these cavities instead.

In general, frugivores tend to roost in bat tents constructed in the secondary forest for closer proximity to food sources. It is possible that these same bats use tree cavities in the old growth forest, however, this is not likely.
 
 
 

Works Cited

Brooke, A.P. 1987. Natural History of the Honduran white bat, Ectophylla alba, in Costa

Rica. Master's thesis, Boston University, MA.

Janzen, D.H. 1983. Costa Rican Natural History. The University of Chicago Press,

Chicago. pg 431.

Soule, M.E. 1986. Conservation Biology the Science of Scarcity and Diversity. Sinauer

Associates, Inc. Sunderland Massachusetts.

Terborgh, J. 1992 Diversity and the Tropical Rainforest: Scientific American Library.

New York. pg215-219.

Zar, J.H. 1999. Biostatistical Analysis. 4^th ed. Prentice Hall Inc. New Jersey.