Anthropogenic effects of habitat modification on anuran species diversity in a swamp forest area, Kenya

Abstract

Anuran species are some of the good environmental indicators of habitat quality and condition in ecosystems. This is due to their amphibious life modes and sensitivity to environmental change caused by rapid expansion of agricultural activities, advancement of forest destruction, climate change and emerging infectious diseases. Understanding their diversity and distribution patterns is crucial for the development and implementation of effective species and habitat conservation strategies. The study aimed at assessing and comparing anuran biodiversity and distribution patterns between a protected (North Nandi Forest Reserve) and a non-protected area (Kingwal swamp) to provide additional baseline information, both being among the underexplored areas in Kenya. Data were gathered in both dry and wet seasons, between October 2022 and June 2023 by employing standard sampling techniques for anurans(Visual encounter and pitfall traps with a drift fence) to maximise detection. Three habitat types- farmland, intermediate land and forest were exploited. A total of 1649 individuals from 21 different species, belonging to nine different genera and nine different families were recorded. Ptychadenidae was the most abundant family from the recorded anurans, while Dicroglossidae, Arthroleptidae, Pyxicephalidae and Ranidae were the least. High biodiversity was observed in the forest habitat (Protected) and least in the farmland (non-protected). The wet season had high species abundance, diversity and richness compared to the dry season. There was a significant difference (p < 0.05) in diversity between the habitats in wet season, but no significance difference during dry season (p > 0.05) except for forest and farmland (p < 0.05). There was a significant difference in species abundance between seasons (p < 0.05), and between habitats (p < 0.05) in all seasons except for farmland and intermediate (p > 0.05), as well as farmland and forest (p > 0.05) during the wet season. Habitat type and season had no influence (p > 0.05) on species richness. Anuran biodiversity is a function of habitat diversity and season, with the associated differences in microhabitat structure providing diverse niches and ways of exploring resources. The modest sampling indicates that Kingwal Swamp and North Nandi Forest Reserve are rich and support anuran species, and the differences in anuran biodiversity between the 3 habitats demonstrates that conservation efforts continue to be a priority.