Keanekaragaman dan pola sebaran spesies tumbuhan asing invasif di Cagar Alam Pulau Sempu, Jawa Timur

The presence of invasive alien plant species has been known to cause various negative impacts on ecosystems in the invaded conservation area. This research aims to identify diversity and distribution pattern of invasive alien plants species in Sempu Island Nature Reserve, and to determine the most influential environmental factors to their dispersion. The methods used were the combination ofquantitative vegetation analysis and rapid assessment technique followed by the principal component analysis. As many as 10 invasive alien plants species (belonging to 7 families) have been identified within this conservation area, e.g., Pistia stratoites, Ageratum mexicanum, Vernonia cinerea, Cyperus rotundus, Passiflora foetida, Centotheca lappacea, Eleusine indica, Imperata cylindrica, Hedyotis corymbosa, and Lantana camara. All invasive alien plant species found in the sampling plots had a clumped distribution pattern. The most influential environmental factors to the invasive alien plants dispersion were land slope and distance from shoreline.