Variation in Allocation of Mechanical Defence Resources in Acacia drepanalobium at Different Foraging Regimes around Hell’s Gate National Park, Kenya

Variation in allocation of mechanical defence resources in Acacia drepanalobium plants in different foraging regimes was investigated around Hell’s Gate National Park, Kenya. The aim of this study was to find out how individual A. drepanalobium plants around Hell’s Gate National Park allocate their mechanical defence resources with varying foraging pressure. Plant architectural attributes (representingmechanical defence) were sampled in 90 individual trees located along transects placed within three foraging regimes: heavily-browsed, moderately-browsed and un-browsed. Thirty trees were sampled in each category. There was a significant increase in defence attributes (thorn size and density) with increasing browsing intensity. On the contrary, trees in the unbrowsed and moderately-browsed area had larger leaf sizes than those in the heavily browsed areas. The study concluded that plants allocated more defence resources with increasing browsing intensity, which had ramifications on plant growth through reduced leaf production. This could have produced the stunted tree growth that was found in the highly browsed area. Thus, our findings suggest that foraging intensity does influence plant architecture.