Classification of the forests of the northern Paraguayan Chaco
Navarro, Gonzalo; Molina, José A.; de Molas, Lidia Pérez
The forests of the northern Paraguayan Chaco are described and classified using phytosociological methods and numerical analysis. Forest types are based on the close relation between the different floristic combinations detected and the variations in soil, bioclimate and biogeography of the northern Paraguayan Chaco. Seven main groups are recognized: 1) Forests on sandy soils of the Médanos; 2) Xerophytic forests on well-to fairly well-drained soils of the old alluvial plains; 3) Forests on poorly-drained soils of the north-western Chaco; 4) Chaco to Chiquitanía transitional forests; 5) Forests of the eastern Chaco of the Alto Río Paraguay; 6) Chiquitanía to Chaco transitional forests and shrublands; 7) Hygrophytic and floodable forests. On a more detailed level 26 forest types are identified, with the different types of Quebracho forest being the most common in the territory. From a biogeographical viewpoint the Chacoan forests are the most extensive while the Chiquitanian forests are restricted to the far north-east of the northern Paraguayan Chaco. Within the Chacoan forests in turn two large transitional groups can be seen: towards the Chiquitanía (the Cerrado) and towards the Pantanal. From an ecological viewpoint, the processes related with the degree of drainage of the soils and the possibility of flooding are the main factors in the floristic and structural characterization and distribution of the Chacoan forests.