Module 14: Exotic Species Introduction Cameron, Barney, Puja, Nate, Crystal, Rachael Atlantic Forest, Brazil SEE-U 2000
Introduction • Exotic species currently are the second greatest threat to biodiversity behind habitat loss (Wilson, 2000) • Exotic species may greatly affect the level of biodiversity in an area (increase/decrease). Eucalyptus plantations are very common in Brazil • Eucalyptus plantations are common in Brazil
Objective • This study was designed to measure the regeneration of woody species in an Atlantic Forest compared to a Eucalyptus spp. plantation in order to see the impact of exotic species on biodiversity
Methodology • Data along 35 meter transects was collected from two different forest habitats (Atlantic Forest, Eucalyptus plantation) with replicates at each site • Plots of .25m2 were used every 7m to sample regeneration of woody plant species • Insect morphospecies richness and diversity was qualitatively measured as an indicator of diversity • Canopy cover was measured using a densiometer at 7 m intervals • Leaf litter was measured in order to study the conditions conducive to growth of woody species
Results • There was a significant difference in canopy coverage between sites (Atlantic Forest=85%, Eucalyptus site=64%, t=4.35, p<0.05) • There was no statistical difference in regeneration between the two sites (t=-1.53, p<0.05) • The total number of insects found in the Atlantic Forest was 39 and in the Eucalyptus forest, 40.
Discussion • The Eucalyptus spp. plantation (exotic) had lower amounts of regeneration of woody plants than the Atlantic Forest • The abundance of insects showed little difference in number between the two sites • The Eucalyptus was dominated by an exotic grass (molasses), which does not spread if no disturbance takes place on site
Discussion con’d • Exotic species do not necessarily reduce biodiversity in an area
Literature Cited • Wilson, E.O., (2000) Conserving Earth’s Biodiversity (Island Press: Washington D.C.) cd rom