RAMIREZ-SOSA, CARLOS R.* AND DWIGHT T. KINCAID. Department of Biological Sciences, Lehman College and The Graduate School, The City University of New York, Bronx, NY 10468 USA. - Tree Species Diversity in Forest Fragments in El Imposible National Park, El Salvador, C.A.
The Pacific coast of Central America has been impacted by humans and
most of its forests have disappeared. However, patches still remain of
forested areas where we find flora representative of what might have
been before humans settled in the region. El Salvador, the most
deforested country in the Western Hemisphere, contains small fragments
of forests that house a relatively diverse community of trees. We
conducted forest inventories in three sites (2.8 ha) within El
Imposible National Park. Our main objective was to determine the state
of the tree community after human disturbance: two areas where
selective tree harvesting occurred ( Site 1 & 3) and an abandoned
coffee plantation (Site 2, all events 18 years ago). In each site, we
established permanent plots (20 x 50 m) and included all woody stems
equal or greater than 5 cm DBH. We measured DBH (cm), height (m),
x,y-coordinates, and nearest neighbor distances. This report is based
upon Sites 1 & 2. We identified 103/ha species in site 1 and 110/0.8
ha in site 2. The dominant species in site 1 is Brosimum
alicastrum (Moraceae, I.V.=30.59) and in site 2, the dominant
species is Alstonia longifolia(Apocynaceae, I.V.=38.7).
Interestingly, the abandoned coffee plantation has about one third
more woody species (138/ha) than the site selectively cut. At both
sites, about 33% of the species occur as a single tree, resulting in
steep species-area curves. In site 1 the counts are not randomly
distributed (index of dispersion of 2.2, P=0.02 in 999 Monte Carlo
simulations of CSR); however there is no spatial autocorrelation of
these trees (P=04 in Mantel test). We conclude that regardless of the
human disturbance suffered by these forests and the little disturbance
thereafter, this area still contains a diverse tree species
diversity.
Key words: El Imposible National Park, El Salvador, forest fragments, forest inventory, tropical tree diversity