Thailand has approximately 15,000 species of plant accounted for 8% of estimated total number of plant species found globally (OEPP, 1992). Thailand also has approximately 1,721 species of terrestrial vertebrate, including mammals, birds, reptiles and amphibians (Theerakupt and Panha, 2002) in comparison to 299 and 328 species found in Norway and Sweden, respectively (WCMC, 1992).