Transcript Exotic Species Influence on the Local Environment

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.
Abundance of Woody Species
Transect 1
Atlantic Forest Eucalyptus
site
site
30
8
Transect 2
40
25
Total
70
33
Abundance of Insects
Transect 1
Atlantic Forest Eucalyptus
site
forest site
7
15
Transect 2
33
24
Total
40
39
Leaf Litter
Transect 1
Atlantic Forest Eucalyptus
site
forest site
~2-3cm
~8-10cm
Transect 2
~2-3cm
~5cm
Average Total ~2-3cm
~8cm
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