Restoration of tropical forest depended in large part on seed dispersal by fruit-eating animals that transported seeds into planted forest patches. We tested effectiveness of dispersal agents as revealed by established recruits of tree and shrub species that bore seeds dispersed by birds, bats, or both. We documented restoration of dispersal processes over the first 76 months of experimental restoration in southern Mexico. Mixed-model repeated-measures randomized-block ANOVAs of seedlings recruited into experimental controls and mixed-species plantings from late-secondary and mature forest indicated that bats and birds played different roles in the first years of a restoration process. Bats dispersed pioneer tree and shrub species to slowly regenerating grassy areas, while birds mediated recruitment of later-successional species into planted stands of trees and to a lesser extent into controls. Of species of pioneer trees and shrubs established in plots, seven were primarily dispersed by birds, three by bats and four by both birds and bats. Of later-successional species recruited past the seedling stage, 13 were of species primarily dispersed by birds, and six were of species dispersed by both birds and bats. No later-successional species primarily dispersed by bats established in control or planted plots. Establishment of recruited seedlings was ten-fold higher under cover of planted trees than in grassy controls. Even pre-reproductive trees drew fruit-eating birds and the seeds that they carried from nearby forest, and provided conditions for establishment of shade-tolerant tree species. Overall, after 76 months of cattle exclusion, 94% of the recruited shrubs and trees in experimental plots were of species that we did not plant.

Unassisted secondary succession in abandoned tropical pastures often results in species‐poor forests of pioneer trees that persist for decades. We characterize recruitment rates of woody vegetation in planting treatments during the first 60 months of experimental restoration on thin, eroded soils at Los Tuxtlas, southern Mexico. We test the hypothesis that recruitment of later‐successional trees is greater in fenced plots planted with native trees than in fenced controls that simulate natural succession, and further that recruitment of such species would be greater in plots planted with animal‐dispersed trees than in those planted with wind‐dispersed trees.Results indicated much greater recruitment of later‐successional animal‐dispersed trees in planted plots as compared with controls. Three censuses per year recorded 960 recruited individuals of 44 species of trees and shrubs from 20–60 months after cattle exclusion. Ninety‐six percent of recruits were not of planted species. Repeated‐measures analyses of variance indicated that recruited communities included more species of pioneers than of later‐successional trees and shrubs, with more individuals and species dispersed by animals than by wind. Recruitment of pioneers did not differ between control and planted plots. Later‐successional recruits dispersed by animals accumulated >10 times faster in planted than control plots, with apparent acceleration after planted Cecropia obtusifolia and Ficus yoponensis first produced fleshy fruits 48 months after cattle exclusion. Sparse later‐successional wind‐dispersed recruits did not differ by treatment. Our preliminary results over the first five years after cattle exclusion indicate that planted stands clearly accelerate succession through accumulation of later‐successional trees and shrubs dispersed by animals.

Seed dispersal into fragmented tropical landscapes limits the rate and character of ecological succession between forest remnants. In a novel experiment in recovery of dispersal between forest remnants, 120 1-m² seed traps were placed in fenced plots in active pasture 90–250 m from forest, and in nearby primary and secondary forests. Total seed rain from December 2006 to January 2008 included 69 135 seeds of 57 woody species. High richness of seed rain of early-successional trees occurred in all habitats, but seed rain of late-successional woody plants was much lower into pastures and secondary forest than into old-growth forest. Non-metric ordination analysis further demonstrated high movement of late-successional species within and between forest and secondary forest, but little movement of species of either forest type to pastures. Most species were dispersed by animals, but most seeds were dispersed by wind. A pattern of seed rain biased strongly towards wind-dispersed species creates a template for regeneration quite unlike that in nearby forest.

Pantropical variation in soils of the tropical dry forest (TDF) biome is enormously high but has been poorly characterized. To quantify variation in the global distribution of TDF soil physical and chemical properties in relation to climate and geology, we produced a synthesis using 7500 points of data with gridded fields representing lithologic, edaphic, and climatic characteristics. Our analyses reveal that 75 TDF ecoregions across five biogeographic domains (Afrotropical, Australasian, Indo-Malayan, Neotropical, and Oceanian) varied strongly with respect to parent material: sediment (57%), metamorphic (22%), volcanic (13%), and plutonic (7%). TDF ecoregions support remarkably high variability in soil suborders (32), with the Neotropical and Oceanian realms being especially diverse. As a whole, TDF soils trend strongly toward low fertility with strong variation across biogeographic domains. Similarly, the exhibited soil properties marked heterogeneity across biogeographic domains, with soil depth varying by an order of magnitude and total organic C, N, and P pools varying threefold. Organic C and N pool sizes were negatively correlated with mean annual temperature (MAT) and positively correlated with mean annual precipitation (MAP). By contrast, the distribution of soil P pools was positively influenced by both MAT and MAP and likely by soil geochemistry, due to high variations in soil parent material across the biogeographic domains. The results summarized here raise important questions as to how climate and parent material control soil biogeochemical processes in TDFs.