The influence of Lantana camara invasion on plant, mammal and avifauna diversity in Katonga wildlife reserve, western Uganda

Abstract

Invasive plant species are a growing threat to biodiversity and ecosystem integrity worldwide. In Uganda Lantana camara, is one of the most aggressive invaders that have spread across Uganda’s protected areas, yet its ecological impacts in savanna ecosystems remain poorly documented. This study assessed the influence of Lantana camara invasion on the diversity of native plants, avifauna, and medium to large mammals in Katonga Wildlife Reserve, Western Uganda. Six transects (three invaded and three non invaded) were surveyed using quadrats, point count, and line transect methods, for plants, avifauna and mammals respectively A total of 103 plant species, 92 bird species, and 14 mammal species were recorded. Plant species diversity was significantly higher in non invaded sites than the invaded (t (26) = 4.201, p = 0.0003). In contrast, avifauna diversity across ecological categories and feeding guilds, as well as mammal diversity based on feeding guilds, did not differ significantly between invaded and non invaded sites. Community composition differed significantly between invaded and non invaded sites for plants (Global RANOSIM = 0.377, p = 0.001), avifauna (Global RANOSIM = 0.110, p = 0.003), and mammals (Global RANOSIM = 0.407, p = 0.001). SIMPER analysis indicated that plant community dissimilarity was primarily driven by Cymbopogon afronardus Stapf (17.04%), Setaria sphacelata (Schumach.) Stapf & C.E. Hubb. ex Moss (9.53%), Cynodon dactylon (L.) Pers. (5.07%), and Panicum maximum Jacq. (4.61%). For avifauna, the species contributing most to dissimilarity between invaded and non invaded transects included Cuculus solitarius Stephens (3.59%), Colius striatus Gmelin (2.99%), Pycnonotus barbatus Desfontaines (2.88%), and Camaroptera brachyura Vieillot (2.80%). Mammalian dissimilarity was mainly influenced by Kobus ellipsiprymnus Ogilby (3.94%), Tragelaphus scriptus Pallas (3.94%), Xerus erythropus É. Geoffroy Saint Hilaire (3.94%), and Piliocolobus tephrosceles Elliot (3.46%). The findings highlight that Lantana camara significantly alters plant diversity and may indirectly affect faunal assemblages. Based on these findings, it is recommended that the Uganda Wildlife Authority (UWA) prioritize targeted control of Lantana camara in invaded areas and investigate the impacts of invasion of forage quality in the reserve.