Forest fragmentation in the Argentine Chaco: recruitment and population patterns of dominant tree species

Abstract

The forest in the Central Argentine Chaco has been dramatically fragmented and persists only as isolated patches in an agricultural matrix. In this study, we evaluated the effects of fragmentation on total density, recruitment, and size-class structure of its dominant tree species, a key issue, although little explored, for forest conservation in the region. We particularly analyzed the effects of fragment size and forest cover at landscape level on seven of the most important tree species of the forest. Our results suggest that forest cover at landscape level is more important than fragment size to explain the population patterns of the main tree species. Fragment size was relevant in only one species, Cordia americana, whereas forest cover resulted relevant in five species. The size-class structure of Schinopsis balansae, one of the dominant species of the upper stratum, appeared to be affected in landscapes with less forest cover, showing lower densities of the smaller classes. Our results show that for the conservation of the forest it would be important to increase their protection degree against the expansion of agriculture, attempting to preserve as much of the forest as possible, to promote the forest cover at landscape level and give relevance even to the smallest fragments.