Influence of Habitat Structure and Ecological Zones on Amphibian Diversity in Rivers State, Nigeria

Research on amphibian diversity in Rivers State, Nigeria, was conducted between 2015 and 2019. The survey covered seven Local Government Areas and three ecological zones (lowland forest, freshwater swamp and short mangrove). The surveyed areas were Ikwerre LGA (Isiokpo), Emohua (Rumuji and Ndele), Okrika (Fiberesima Polo, ATC sandfill, Greame Ama), Khana- Ogoni (Bori, Kaani 1), Ogba-Egbema-Ndoni (Omoku), Ahoada East (Ahoada main town, Ikata) and Obio-Akpor (Agbada, Rumuagholu, Rumuesara). The habitats included farmlands, fallow areas, swamps, streams and inundated areas, bush paths, human settlements and forested areas. Visual encounter and acoustic survey methods were used. Nineteen amphibian species were encountered including members of the Arthroleptidae, Bufonidae, Dicroglossidae, Ranidae, Hyperoliidae, Ptychadenidae and Pipidae. Freshwater swamps and short mangrove ecological zones (characterized by human settlements and farmlands) had the lowest diversity of two and five amphibian species, respectively. The highest diversity comprised of eighteen different amphibian species was recorded in forested habitats of the lowland forest/freshwater swamp ecological zone. 569 individuals were collected from lowland forest/freshwater swamp ecological zone; 215 from lowland forest; 60 from short mangrove; and 28 from freshwater swamp ecological zone. Shannon diversity was highest in the lowland/freshwater swamp ecological zone (H=2.12) and lowest in the freshwater swamp zone (H=0.52). It is concluded that a forested habitat comprised of the combination of lowland forest and freshwater swamp ecosystems hosts a greater diversity of amphibian species.