Effects of large mammal exclusion on seedling communities depend on plant species traits and landscape protection in human-modified Costa Rican forests

Large terrestrial herbivorous mammals (LTH-mammals) influence plant community structure by affecting seedling establishment in mature tropical forests. Many of these LTH-mammals frequent secondary forests, but their effects on seedling establishment in them are understudied, hindering our understanding of how LTH-mammals influence forest regeneration in human-modified landscapes.
We tested the hypothesis that the strength of LTH-mammals’ effects on seedling establishment depends on landscape protection, forest successional stage, and plant species’ traits using a manipulative field experiment in six 1-ha sites with varying successional age and landscape protection. In each site, we established forty seedling plot-pairs, with one plot excluding LTH-mammals and one not, and monitored seedlings of 116 woody species for 26 months.
We found significant effects of LTH-mammal exclusion on seedling survival contingent upon the protection of forests at the landscape level and forest stage. Afte...