Vegetation Structure and Diversity Under Farmer Managed Natural Regeneration: A Comparison of Silvo‐Arable and Silvo‐Pastoral Systems in Kenya

ABSTRACT Farmer Managed Natural Regeneration (FMNR) is a low‐cost, adaptable agroforestry practice that enhances land restoration by promoting systematic integration of naturally regenerating trees within farming systems through tree selection and management. Despite its increasing adoption in sub‐Saharan Africa, comparative evidence across land uses remains limited. This study empirically compares tree and woody regeneration density, species richness, and composition between silvo‐arable (maize cultivation) and silvo‐pastoral (grazing) FMNR systems in semi‐arid Kenya. Sixty‐three plots were established across these two land uses, within which a total of 1409 trees and 505 woody regeneration individuals were recorded. Tree density was higher in silvo‐pastoral FMNR systems (558/ha) than in silvo‐arable systems (150/ha), though the difference was not statistically significant. In contrast, woody regeneration density was significantly greater in silvo‐arable systems (2450/ha vs. 727/ha). Rarefied species richness of trees was the same in silvo‐arable FMNR and silvo‐pastoral FMNR systems, while richness of regeneration was either significantly higher than the tree community, like in silvo‐arable systems, or significantly lower than the tree community, like in silvo‐pastoral systems. Non‐metric multidimensional scaling showed that silvo‐pastoral FMNR systems exhibited similar species composition between trees and regeneration, whereas silvo‐arable FMNR systems displayed greater variability in tree composition across fields, reflecting less variable preferences by farmers. Given that regeneration represents future tree communities, reduced regeneration diversity in silvo‐pastoral systems may constrain long‐term species richness. These findings suggest that silvo‐arable and silvo‐pastoral FMNR systems follow distinct restoration pathways, with implications for biodiversity conservation, livelihoods, and the scaling of FMNR as a restoration practice.