Sampling effort and species richness of Angiosperms in the state of Ceara, Brazil

(Sampling effort and species richness of Angiosperms in the state of Ceara, Brazil). The state of Ceara, located in northeast Brazil, has a predominantly semi-arid climate. To guide future inventories of the flora, a preliminary survey of collections in the state was made, where we analyzed sampling effort and species richness of Asteraceae, Euphorbiaceae, Fabaceae, Poaceae and Rubiaceae. Geographic distribution of the samples was correlated to the seven phytoecological units of Ceara state: caatinga arbustiva, caatinga arborea, carrasco, cerradao, complex litoraneo, mata seca and mata The data were obtained from the Prise Bezerra Herbarium (EAC) collection and were combined using the software BRAHMS. From 1933 to August 2008, this collection registered the following: 11,551 exsiccatae (exs.) representing 1,209 species (spp.). This total number of exsiccatae is distributed as follows among the phytoecological units: mato timida 27% exs. and 33% spp., complex litoraneo 24% exs. and 24% spp., caatinga arbustiva 16% exs. and 19% spp., carrasco 13% exs. and 17% spp., mata seca 10% exs. and 9% spp., caatinga arborea 8% exs. and 12% and cerradao 2% exs. and 3% app. These data reveal greater collection effort and species richness in areas of mata amida and complex litoraneo, followed by areas of caatinga arbustiva and caatinga arborea. With only 5% of Ceara's territory, sampling in mato timida surpasses that in caatingas, the latter with 70% of the state's territory. Therefore, a satisfactory number of collections in mata amida was observed to the detriment of other units, making it necessary to draw up new projects aimed at a greater effort in these sub-sampling collection areas.