DIVERSITY OF THE FAMILY POACEAE (GRAMINEAE) IN THE REGION OF BIO-BIO, CHILE, BASED ON HERBARIUM COLLECTIONS

The Region of Bio-Bio is located on the southern edge of central Chile, considered a hotspot of biodiversity. Although the region is strongly disturbed by human activities, mainly agriculture, forestry, industrialization and urbanization, it has a low percentage of area covered by the National System of Protected Areas (SNASPE). Thus, to document the regional biodiversity is a critical task. The diversity of the family Poaceae (Gramineae) in the Region of Bio-Bio, Chile, was studied on the basis of data obtained from the databases of the herbaria of the University of Concepcion (CONC) and the National Museum of Natural History (SGO), as well as from the taxonomic literature. Maps showing the collecting intensity and species richness were made. To assess the completeness of the inventory a rarefaction curve was constructed and the estimated species richness was calculated by the non-parametric indices Chao2 and ICE. The grass flora of the Region of Bio-Bio, identified from 3,069 specimens, consists of 234 species and 11 infraspecific taxa, distributed in 76 genera and 8 subfamilies. A total of 66.2% of the species are native (155 species), including 11.5% (27 species) endemic from Chile and 54.7% (128 species) native from Chile but not endemic; 33.7% (79 species) are introduced. The subfamilies better represented in number of species are Pooideae (73.08%), Panicoideae (12.39%), Danthonioideae (5.98%) and Chloridoideae (4.70%). The values of estimated richness suggest that the inventory of Poaceae has been completed in 83-85%, which means that about 40 species could still be recognized in the Region of Bio-Bio.