Power Line Corridors in a Protected African Savanna Alter Vegetation Structure and Avian Community Composition: A Mixed-Methods Assessment

Overhead power infrastructure presents a documented but under quantified risk to biodiversity in protected areas, and sub-Saharan empirical evidence remains particularly scarce. We evaluated vegetation and avian community patterns associated with a power line corridor in Hell’s Gate National Park, Kenya, using a concurrent mixed-methods design combining ecological field surveys with key informant interviews (KIIs). Sampling spanned 15 impacted plots beneath an active power line and 15 control plots (~140 m away) across dry and wet seasons, alongside KIIs with 15 power, conservation, and policy experts. Vegetation beneath power line corridors showed marked structural simplification: woody canopy cover was 52–53% lower, plant density 47% lower, and mean DBH and herb height significantly reduced (all p ≤ 0.030). Woody-layer species richness and Shannon diversity were significantly lower in impacted plots (both p ≤ 0.045). Total bird abundance and diversity indices did not differ significantly between treatments, yet PERMANOVA revealed strong compositional reorganisation (F(1,28) = 8.871, R2 = 0.241, p = 0.001). Eleven out of 15 quantitative–qualitative comparisons showed convergence between ecological observations and expert perspectives. Together, the evidence indicates substantial differences in vegetation structure and avian community composition associated with the studied corridor, highlighting the importance of early ecological planning.