ABSTRACT Fragmented tropical forests urgently need practical, cost‐effective tools to assess ecosystem health and direct management resources where they matter most. Butterflies of the genus Charaxes are promising candidates: their larvae depend on specific woody host plants, and adults are readily sampled using fruit‐baited traps, linking assemblage patterns directly to forest structure and quality. We assessed Charaxes diversity, disturbance responses and habitat associations across North Nandi Forest (~11,000 ha; 1700–2130 m a.s.l.) and South Nandi Forest (~15,000 ha; 1600–2000 m a.s.l.), two of Kenya's last Guineo‐Congolian rainforest fragments. Six sites spanning a disturbance gradient were sampled monthly throughout 2023, with Van Someren‐Rydon fruit‐baited traps and visual censuses deployed concurrently at all sites to ensure comparability. A total of 1847 individual Charaxes belonging to 18 species were recorded. Both forests maintained high diversity (Shannon H ′ = 2.61–2.64; Pielou's J ′ > 0.91) and log‐normal rank‐abundance distributions, confirming intact community structure. Species inventories were near‐complete (Chao1: 90%–95%). Total Charaxes abundance declined by 61% from intact to heavily disturbed sites (Kruskal–Wallis H (2) = 14.32, p = 0.001, η 2 = 0.72), with three forest specialists, Charaxes cithaeron , C. violetta and C. zoolina , declining by 72%–76% and showing strong fidelity to closed‐canopy habitats (79%–84% of captures under shade). Canonical correspondence analysis explained 52.3% of species–environment variation ( F (5,6) = 3.14, p = 0.002, 999 permutations), with Prunus africana density ( r = 0.68), canopy cover ( r = 0.64) and host plant richness ( r = 0.61) as the strongest predictors. Bioindicator evaluation using IndVal analysis identified four robust candidate species (IndVal 68.7–76.3, p < 0.005), and significant compositional turnover between forest blocks (βSIM = 0.38) confirmed that each contributes uniquely to regional diversity. Based on these findings, we recommend equal conservation investment in both forests, maintaining canopy cover above 70%, targeted protection and enrichment planting of P. africana and Turraea stapfiana , and a tiered monitoring protocol using the three specialist species as early‐warning bioindicators of forest deterioration.
Tsingalia et al. (Wed,) studied this question.