Pteridophyte diversity along a gradient of disturbance within mines in Thong Pha Phum District, Kanchanaburi Province

Abstract

The diversity of pteridophyte in Thong Pha Phum District, Kanchanaburi Province was conducted along a gradient of disturbance within mines, from July 2002 to March 2003. Twelve plots of 5 x 20 meters have been established in each three study sites, i.e. abandoned mines, remnants of the forest in mine area and natural forests. Pteridophyte diversity was determined by counting the number of species and individuals in each plot. Species richness, species diversity and species evenness indices were estimated using Menhinicks, Shannon-Weiners and evenness indices, respectively. Species similarity was investigated using Jaccards coefficient. Other physical environments related to pteridophyte diversity were examined, including light intensity and leaf temperature. Species richness and species diversity of abandoned mines were lower than those of remnants of the forest in mine area and natural forests, while species evenness was the highest of all. Low Jaccards coefficient was observed, indicating the difference of pteridophyte species between each sites. Light intensity and leaf temperature showed negative significant correlation with Menhinicks index, but was positively significantly correlated with evenness index. However, significant correlation between those physical factors and Shannon-Weiners index was not found. One hundred and eighty-four specimens of pteridophytes were collected from the 36 sampling plots and identified to 65 species, 1 subspecies, 5 varieties, in 40 genera, from 20 families. Among these 8 species, 2 genera, 2 families are fern allies. It was found that Cheilanthes tenuifolia (Burm. f.) Sw., Sphenomeris chinensis (L.) Maxon var. divaricata (H. Christ) K.U. Kramer and Lycopodiella cernua (L.) Pic. Serm. were found only in abandoned mines and tend to be indicator species for disturbed areas. Two terrestrial ferns, namely Lindsaea ensifolia Sw. and Pteris biaurita L. were commonly found in all study sites. They can be found on rather dryslopes or sandy ground, usually in open areas, but rarely on rocks. Dichotomous keys to species, full description, together with ecological data, distribution and vernacular name of each species were prepared. In addition, photographs and line drawings of some species were also provided.