Abstract
The effect of forest exploitation--timber and palmito (Euterpe edulis, Palmae) extraction--on structure, diversity, and floristic composition of forests known as palmitals of the Atlantic Forest of Argentina was analyzed. These palmitals are located in Misiones (54 degrees 13' W and 25 degrees 41' S). Three 1 ha permanent plots were established: two in the "intangible" zone of the Iguazu National Park (PNI), and another in an exploited forest site bordering the PNI. Three 0.2 ha non-permanent plots were also measured. One was located in the PNI reserve zone where illegal palmito extraction occurs. The other two were in logged forest. All trees and palmitos with DBH >10 cm were identified and DBH and height were measured. For each of the six sites, richness and diversity of tree species, floristic composition, number of endemic species, and density of harvestable tree species were estimated. The harvest of E. edulis increases density of other tree species, diminishing palmito density. Forest explotation (logging and palmito harvest) is accompanied by an increase in diversity and density of heliophilic species, which have greater timber value in the region. However, this explotation also diminishes the density of palmito, of endemic species which normally grow in low densities, and of species found on the IUCN Red List. Results suggest that forest structure may be managed for timber and palmito production. The "intangible" zone of the PNI has the greatest conservation value in the Atlantic Forest, since a greater number of endemisms and endangered species are found here.
Highlights
Los palmitales son bosques naturales que se encuentran en la Selva Atlántica y que se caracterizan por tener una alta densidad de palmito (Euterpe edulis Mart., Palmae) (Placci y Giorgis 1993)
Más los árboles de especies maderables, hacen del palmital uno de los bosques nativos de la Selva Atlántica interior de mayor valor económico
Si el aprovechamiento no es selectivo y se cortan todas las especies o especies subdominantes se produciría un decremento en la riqueza de especies
Summary
Área de estudio: Se trabajó en palmitales ubicados alrededor de las coordenadas 54 °13’ O y 25°41 ́ S, en zona norte de la provincia de Misiones, Argentina. Todas las plantas (árboles, palmeras y lianas) con diámetro de tronco a una altura de 1.3 m del suelo (DAP) igual o mayor a 10 cm fueron marcadas con chapas metálicas numeradas y se registró la especie, altura total y perímetro de tronco. Para cada sitio se estimó densidad, área basal, altura promedio y máxima y estructura diamétrica y altimétrica del bosque considerando a las plantas con DAP >10 cm (Dallmeier 1995). Para determinar como varía la diversidad específica con el aprovechamiento se realizó una correlación de Spearman entre la densidad de palmitos promedio en 0.2 ha con el índice de Shannon de cada sitio. También se correlacionó la riqueza de especies en cada una de las hectáreas de las parcelas permanentes y la estimada para los sitios no permanentes con la densidad de palmitos. Lianas were not taken into account to estimate the height, richness and diversity of species
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