"Spatial pattern of herbaceous seed dispersal by ungulates in grasslands of the Donana National Park (SW Spain)".

Abstract

Most research on endozoochorous seed dispersal by ungulates emphasizes long-distance dispersal and its dependence on ungulate species and habitat heterogeneity. In contrast, the role of ungulate community composition in shaping short-distance dispersal and generating spatial patterns in the distribution of plant diaspores remains largely unexplored-- key questions addressed in this study. We conducted fieldwork at two adjacent grassland sites in Donana National Park (southwestern Spain). One site was used by a mixed community of four ungulate species--both wild and domestic (deer, wild boar, cattle, and horses)--while the other was used almost exclusively by deer. Our results revealed clear differences between sites in the total number of dispersed herbaceous seeds and the most frequently dispersed plant families. Within the four-species community, cattle and deer differed most in the taxonomic composition of the seeds they dispersed, suggesting that herbivore-specific seed selection and dispersal act as key drivers of grassland structure at fine spatial scales, mirroring dynamics typically observed at broader scales. Moreover, only in the four-ungulate community did we detect significant spatial patterns in seed dispersal. These included positive effects of short-distance feces aggregation, spatial covariance in seed content among nearby feces, and a strong correlation between seed content and local feces density. Seed families predominantly dispersed by cattle also exhibited significant spatial structuring. These findings have important implications for biodiversity management in semi-natural and protected ecosystems, underscoring the need to consider functional differences among herbivores when developing conservation and restoration strategies.