Seed Morphology and Dispersal Trade-offs in Three Tropical Trees of Semi-Arid Northern Nigeria

Abstract

Seed morphology and dispersal mechanisms critically influence plant population dynamics, regeneration, and spatial distribution in semi-arid tropical ecosystems. This study examined relationships between seed traits and dispersal patterns of three ecologically and economically important tree species—Albizia lebbeck, Delonix regia, and Azadirachta indica—at the Take-Up Site of the Federal University Dutsin-Ma, Katsina State, Nigeria. A total of 90 seeds per species were collected using systematic quadrat sampling. Seed weight, length, and structural characteristics were measured, while dispersal distances were recorded. Trait–dispersal relationships were analyzed using one-way ANOVA and Pearson correlation. Significant interspecific variation was observed (p < 0.05). Albizia lebbeck produced the smallest and lightest seeds (0.10 ± 0.02 g; 0.91 ± 0.05 cm) and exhibited the greatest dispersal distance (3.19 ± 0.30 m). Delonix regia had the largest seeds (0.44 ± 0.08 g; 1.98 ± 0.15 cm) with shorter dispersal (2.75 ± 0.25 m), while Azadirachta indica showed intermediate traits (0.36 ± 0.07 g; 1.48 ± 0.12 cm) and dispersal distance (2.77 ± 0.28 m). Seed weight and length were strongly negatively correlated with dispersal distance (r = -0.983 and -0.902, p < 0.01). These patterns illustrate the ecological trade-off between dispersal and establishment, where lighter seeds enhance colonization potential while heavier seeds favor seedling survival. Albizia lebbeck is suited for colonizing degraded landscapes, Delonix regia for managed plantings, and Azadirachta indica for adaptive, heterogeneous systems. However, potential limitations related to seed–parent association and unmeasured environmental dispersal drivers should be considered when interpreting these findings. Understanding these trait–dispersal relationships supports evidence-based species selection, propagation strategies, and restoration planning in semi-arid ecosystems