Forest communities in secondary high Andean forests (Azuay, Ecuador)

Abstract

In the mountains of southern Ecuador there are areas occupied by high Andean secondary forests formed as a result of anthropogenic activities. Here we identified different secondary forest communities located above 2,900 m a.s.l., based on their floristic similarity. In each community the floristic composition was described by total, exclusive and shared species. Estimation curves were used to provide richness and diversity metrics. Structure was analyzed according to abundance and basal area. In addition, the role of environmental variables in explaining floristic conformation and structure was evaluated through principal component and redundancy analysis. Three forest communities were identified. The highest value in diversity and basal area was for the community located at the highest altitude and lowest temperature. Variation in species composition was explained by climatic and geographic environmental variables, density by edaphic and climatic variables, and basal area by topographic variables. Species richness and basal area did not show a similar altitudinal distribution pattern with other Andean tropical forests. Therefore, it was deduced that floristic variation, species richness and basal area are also explained by the chronological age of secondary succession, as shown by indicator species belonging to different ecological groups. It was concluded that floristic composition, richness and vegetation structure in forest communities of high Andean secondary forests are influenced by climatic, topographic, physiographic and geographic variables linked to the age of succession.