The study was conducted to assess the native and alien plant species in one of the highly disturbed forest (S1) and less disturbed forest (S2) in Mt. Manunggal, Cebu Island, Philippines. Twenty-four quadrats with a size of 20mx20 m were established using a quadrat sampling technique to identify and record all plant species. Diversity indices were utilized to determine species abundance, richness, evenness, and diversity. There was also the characterization of sites concerning anthropogenic activities and economic uses of native and alien plant species. Results showed that there was apparent domination of alien plants in terms of species richness and abundance in both sites (S1; R=62 species; N=10519; S2; R=55; N=32739). However, there was higher species richness (S1; R=62 and S2; R=30) and diversity (S1; H’=2.76, D=0.10 and S1; H’=2.41, D=0.11) but lower abundance (S1; N=10519 and S2; N=32739) and evenness (S1; PE=0.67 and S2; PE=0.73) in S1 than in S2. The high abundance and evenness of alien plant species in S2 could be due to high anthropogenic activities and its economic value. These factors indirectly assist in the introduction and persistence of alien plant species in disturbed ecosystems by increasing alien plant invasion which usually results in a higher diversity of alien plant species in highly disturbed sites. Assessment on the negative impacts to native plant species by alien plant invasion, enhanced by anthropogenic activities, must, therefore, serve as bases in future directions and implication for restoration and conservation of the remaining forests of Mt. Manunggal, Cebu Island, Philippines.
- Alien plant species can outnumber native plant species in terms of species abundance and diversity due to morphological, physiological, and ecological factors;
- Environmental factors and anthropogenic activities indirectly assist in the introduction and proliferation of alien plant species;
- Alien plant species have greater phenotypic plasticity, which is particularly beneficial in disturbed areas where environmental conditions and anthropogenic activities are in frequent flux.