Floristic analysis in an altitudinal gradient located in the Cerro Mecana, in the Chocó Biogeográfico

Abstract

The analysis of the vegetation in an altitudinal gradient between 200 and 650 meters above sea level in the Mecana hill, allowed registering 488 individuals, belonging to 38 families, 88 genera and 122 species. Arecaceae, Melastomataceae, Sapotaceae, Clusiaceae, and Rubiaceae were the most abundant families in the entire gradient with 79, 58, 37, 35 and 29 individuals respectively. The composition of species and genera decreased as the amount of the gradient increased, while the number of families was little variable. This, as a consequence of the characteristics and particularities expressed throughout the ecosystem. The stations E1 and E2, have similarity in 75% of the species, and these in turn have 51 and 36% similarity with the E4 and E3 respectively. The exclusivity of species increased from the lowest station E1 to E3, which registered 42% of species. Growth habits show that 30% of individuals are shrubs, 27% trees, 22% herbs, and 21% palms. Therefore, the largest number of individuals, was located in the lower diameter classes showing inverted “J” behavior, that is, many juvenile individuals and few mature trees. The most representative species according to the value index of importance (VII) in the altitudinal gradient evaluated were: Pouteria cuspidata with 24% of the VII; Vismia macrophylla with 13.9%; Chrysochlamys floribunda 12.2%; and Carapa guianensis 10.8%; and Licania chocoensis with 10.3% of the total VII. At least 15 species have some degree of threat, and are represented in the families: Arecaceae, Apocynaceae, Chrysobalanaceae, Cyatheaceae, Humiriaceae, Malvaceae, and Myristicaceae.