Abundance and Distribution of Afrosteles distans an Indicator of Food Availability for the Kihansi Spray Toad (Nectophrynoides asperginis) in the Kihansi Gorge

Abstract

Survivorship of the Kihansi Spray Toad in the wild depends on various factors such as environment, habitat, food availability, diseases and predation. This study assessed the abundance of Afrosteles distans Linnavuori 1959 as an indicator of food availability for the Kihansi Spray Toad. Samples were collected from sprinkled (A, B, C, D, E and F) and non-sprinkled (G and H) plots in the upper spray wetland in the Kihansi gorge during the dry period in 2007, 2008, 2015, 2016 and 2018. There was a significantly higher abundance of A. distans in sprinkled than non-sprinkled plots. ANOVA showed significant differences in the abundance of A. distans among plots in each year. ANOSIM (Global R = 0.756, p = 0.001) showed a significant difference between plots with an increasing trend (E, F and D) and plots with a decreasing trend (A, B and C). Cluster analysis resulted in 62% similarity of plots A, B and C and 68% similarity of plots E, F and D. Favourable conditions for the A. distans were not homogenous among the sprinkled plots and continued to vary over time. Abundance levels of A. distans and occurrence of other invertebrates indicated that food for the KST was sufficiently available in the gorge.

Keywords: Afrosteles distans; Abundance; Kihansi Spray Toad; KST; Kihansi gorge;