Pioneer and Alien Tree Species Invade Banana Bay Coast Forest Reserve, Kenting National Park, Southern Taiwan

Banana Bay Coast Forest Reserve, 28 ha on area located at Kenting of southern Taiwan, is the only tropical coast forest reserve in Taiwan. Taiwan Forestry Research Institute set up a 1.458 ha (270 m x 54 m) plot in1974 and re-inventoried in 2005 for monitoring the tree species (dbh≧4 cm) dynamics among period of 31 years. The purpose of this study is to clarify if any and how the pioneer and alien tree species invade this coast forest remnant? For clearly explaining the spatial pattern of species distribution, the plot was divided into 3 parallel transects named road-transect, mid-transect and sea-transect. Two pioneer tree species, Macaranga tanarius and Melanolepis multiglandulosa, were recorded; and each of them had 240 and 84 individuals in 2005. It’s 61 and 3.5 times of 1974’s recorded individuals. More pioneer trees distributed in road-transect than in mid-transect, and few in sea-transect in 2005, so it seem the pioneer tree spread from the road to forest interior. More than 100 Leucaena leucocephala, an alien tree species which not found in the plot in 1974, were recorded in 2005,; however, most of them still concentrated at the corner of road-transect, not invaded into the forest interior. This coast forest remnant was sparsely cover by pioneer tree in 1974, nevertheless about half of area significantly invaded by pioneer and alien tree in 2005. Basing on the composition change on temporal and spatial scale, this remnant coast forest will probably seriously corroded by the invasion of pioneer and alien tree. Conservation research and management enforcement such as forest dynamics monitoring, invasive species eradiation, revegetation of old-growth species need to be done for sustaining this coast forest remnant reserve.