Tree diversity in indigenous agroforestry systems and its association with household food security in the subtropical lowlands of Pakistan

Abstract

Agroforestry systems support multifunctional agricultural landscapes, yet their association with household food security remains insufficiently understood in intensively cultivated subtropical lowlands. Limited evidence linking tree diversity with household dietary outcomes constrains the development of nutrition-sensitive agroforestry strategies. This study quantified tree diversity across five indigenous agroforestry systems and assessed its association with household food security in District Kasur, Punjab, Pakistan. A cross-sectional survey of 150 households was conducted with equal representation across the five systems (30 households per system). Tree inventories quantified taxonomic, functional, and phylogenetic diversity, while household food security was assessed using the Household Dietary Diversity Score (HDDS) and Food Consumption Score (FCS). Adjusted regression models evaluated associations of tree richness with HDDS and FCS while accounting for household size, farm size, livestock number, and agroforestry system. A total of 48 tree species representing 20 families were recorded. The largest system-level species pool occurred in STC (32 species), whereas HTG had the highest household-level richness (10.03 ± 0.32), Shannon diversity (2.14 ± 0.04), and phylogenetic diversity (942.62 ± 32.30). BHT showed the highest functional diversity (0.39 ± 0.01) and evenness (0.96 ± 0.01). Tree richness was positively associated with HDDS (β = 0.383, 95% CI = 0.307–0.458, p < 0.001) and FCS (β = 2.920, 95% CI = 2.433–3.407, p < 0.001). The adjusted models explained 70.1% and 74.4% of variation in HDDS and FCS, respectively. Recorded tree species supported ten ecosystem-service categories, including food, fuelwood, timber, fodder, habitat support, shade, soil fertility, windbreak, erosion control, and carbon storage. System-specific diversification of multifunctional trees can strengthen biodiversity conservation and household dietary outcomes in subtropical agricultural landscapes.