当前世界环境

KnemaPhytosociological studies have been carried out in a Myristica swamp in Northern Kerala to reveal the composition and distribution pattern of different tree species. On the basis of IVI, the family Myristicaceae was dominant and the association isattenuata-Myristica malabarica-Holigarna arnottianatype. The species likeGymnacranthera canaricaandMyristica fatuavar.magnificab,这是elieved to be the essential elements of Myristica swamps, are totally absent here. A total 403 individuals (gbh>10.1 cm) were recorded with a basal area of 34.25 m²ha^-1in 0.5 ha. area.Total number of species recorded was 28, which represent 21families in which Myristicaceae represents 48.18% of total IVI. Among two dominant species,Myristica malabaricaprefer swampy area hence their number of individual shows decreasing trend when we move from the swamp while the second dominant speciesKnema attenuatashowing a reverse trend and was completely absent in the first five quadrats where soil water content is too high. Species specific eco-physiological studies are required to understand the reasons for change in the distribution pattern of these dominant species.