Impacts of Forest Types on Formicadae Biodiversity: Native vs Alien Species A Comparison of Secondary Forest versus Eucalyptus Forest in Southern Brazil Maryani P. Rasidjan Columbia University 116 St. and Broadway New York, NY

Introduction The introduction of allien species, specifically forest tree plantations, is a controversial topic in conservation biology. While it is often assumed that introduction of exotic species would eventually deplete the native fauna, certain introductions such as recolonization of past tree species is accepted. At present, in the severely endangered Atlantic forest of Brazil, an estimated 7.3% of the biome’s original surface is left. Of this small amount only 2% are of native forest. Because Eucalyptus plantations are a source of sustainable income for local farmers, they have served as a popular replacement for agricultural deforestation. In Brazil, there are over 3 million hectares of Eucalyptus plantations, and exotic tree species.

?Question?: Is there a relationship between the exotic Eucalyptus forest and native formicadae diversity Null Hypothesis: There would be no difference in ant diversity collected in the Secondary forest and the Eucalyptus forest Expected Hypothesis: There would be more ant diversity in the Secondary forest because it contains native tree species Alternative Hypothesis: There would be more ant diversity in the Eucalyptus Forest

Methods Study Area:Bairro do Moinho, Nazare, Sao Paulo State, S.EBrazil ~ Secondary Forest: *3 strata (2, 7, 11 meters) *dense canopy cover * heterogeneous tree species }both were ~20 years old ~ Eucalyptus Forest: *2 strata (5 and 10 meters) *open canopy * homogeneous species (Eucalyptus) The ants in the canopy and litter samples were collected with an aspirator and then classified by morphotype. Colection was conducted during the day between the hours of 11am and 5pm, during the month of June, winter season. In both study sites the edges were avoided. ~ Data Collection: *pitfalls (1/site and left over a 24 hour period) *litter extractions *15 min tree trunk observations *10 canopy samples (trees 2-5 meters in height)

Results Eucalyptus forest : *21 total species *51 individuals *60% represented by 1 individual * 1%was a dominant species Shannon-Weiner and Evenness Indices indicated greater ant diversity H-value= 2.58 Evenness=.846 Secondary forest: *16 total species *51 individuals *70% represented by 1 individuls *less than 1% was dominant species Shannon-Weiner and Eveness Indices indicated less ant diversity H-value=1.70 Evenness=0.513 Sorenson Coefficient= 4% overlap; 2 species overlap *worker leaf-cutter * terminator

Conclusions The expected hypothesis was disproven as there was more formicade diversity in the Eucalyptus forest This would discount the expected negative influence of the physical and chemical alterations that the Eucalyptus forest would cause Since the open canopy of the Eucalyptus forest would expose more surrounding plants, possibly high level shade plants, to direct sunlight, there would be less dense vegetation. In addition, the reduced plant species might provide more room for ant habitat. This may be why two ant mounds were observed in the Eucalyptus forest and none in the Secondary forest. Moreover the greater open canopy caused drier ground litter, which may indicate why more arboreal ants were found in the Also in order to ensure rapid growth of the Eucalyptus trees, the plantation would most likely have greater soil quality and support a greater ant population lack of predator habitat (anteater) could also enhance ant population in the Eucalyptus forest

~ Statistical Analysis: Shannon-Weiner Index Eveness Index Sorenson Coefficient