Abundanceand impact of Parthenium hysterophorus L., an alien invasive herb on plant species diversity in invaded areas of Queen Elizabeth NationalPark, Uganda

Abstract

Parthenium hysterophorus is an alien annual herb that aggressively threatens biodiversity of Queen Elizabeth National Park (QENP) in Uganda. Occurrence, abundance and impact of P. hysterophorus on plant species diversity were examined. Anobservational inspection survey assessed the occurrence of P. hysterophorus while Quadrats sampled vegetationin P. hysterophorus invaded and uninvaded sites of Mweya Peninsula and along Kazinga Channel Track. Plant species richness, dominance, evenness and diversity of invaded and uninvadedsites were statistically different at P<0.05. Species richness(R) and dominance(D)were higher in invaded sites(R = 58, D = 0.62) than uninvaded sites(P = 0.043; R = 39, P = 0.04;D = 0.46). Consequently, species diversity of other plants became less (1-D = 0.38) in invaded than uninvaded (P = 0.039;1-D = 0.55).Also, P. hysterophorus significantly starts to reduce species diversity and richness at very low levels of abundances, as low as (4.6%)and(7.7%),respectively, and dominates at a relatively higher level(40.2%).It was concluded that P. hysterophorusin QENP, negatively affects the plant species diversity at low levels of abundances through dominance