Tropentag, October 5 - 7, 2004 in Berlin "Rural Poverty Reduction through Research for Development and Transformation"

Effects of Different Land Use Intensities on the Succession of Secondary Forest in the Protected Forest Sumaco, Ecuador

¹Georg-August-Universität Göttingen, Institute of Forest Management, Germany
²Georg-August-Universität Göttingen, Institute for Statistics and Econometrics, Germany
³Georg-August-Universität Göttigen, Institute of Silviculture, Germany

Abstract

Studies on site and forest history provided many useful insights into the effects of human activities on Neotropical forest structure and functions. However, we are still unable to develop a deterministic model to simulate how land use history influences tropical forest structure and succession. The present study tend to enhance our ability both to predict and to manage tropical forest succession. Three forest sites (Rukullacta, Villano and Wawa Sumaco) with different colonisation date and use intensity were selected. The age of the forest ranged between 3 and 22 years. At each site, plots of 500 m² surface (20×25 m) were installed with four repetitions. Within the plots, all trees above 5 cm DBH were identified and measured. According to the results, a regional model was developed to determine the driving factors of secondary forest succession. The number of occurring species depend on the sample area, stand age and land use intensity. The species/area curves of the different sites differ significantly; a correlation between land use intensity and species richness could be observed. Multivariate analysis procedures (Principal Component Analysis) were used in order to determinate the patterns of species replacement and show that land use affect floristic composition following abandonment. A noticeable floristic affinity exist, with an intensive land use in different phases of succession. Stand structure analysis showed differences in aggregation and desegregation due to the succession. The DBH distribution (Weibull function) of the forests is influenced by the grade of anthropogenic disturbance. The Correspondence Analysis determinate the potentiality of the Secondary Forest in different sites. The forests under middle and low intensity of the use, the commercial species exceed 38% in comparison with the forests of high intensity of use.

Keywords: Biodiversity, Correspondence Analysis, Neotropical forest, Principal Component Analysis, regional models, Weibull function

Contact Address: Alvaro Cañadas, Georg-August-Universität Göttingen, Institute of Forest Management, Büsgenweg 5, 37077 Göttingen, Germany, e-mail: acanadauni-forst.gwdg.de