Ambitious global targets to restore tropical forests would benefit from long-term, multi-site field evaluations that compare restoration strategies. We monitored 10,310 individuals across 11 sites in southern Costa Rica to compare tree recruit dynamics in three restoration interventions and reference forests through the second decade of recovery. Early-successional recruits had greater seedling-to-sapling transitions and sapling growth in natural regeneration and applied nucleation compared to plantation treatments during early recovery. Seedling and sapling demographic rates largely converged for all successional groups across restoration treatments after nearly two decades. Whereas species composition in restored plots is following a successional trajectory toward reference forest, all treatments still differ substantially from reference forest, further supporting that tropical forest recovery takes decades to centuries even with active restoration. The persistent divergence in community composition, paired with the scarcity of late-successional recruits, particularly in natural regeneration, underscores that long-term recovery is primarily driven by dispersal limitation.
Nepal aims to eliminate lymphatic filariasis (LF) by 2030. Mass drug administration (MDA) has ceased in 53 of the 64 endemic districts. Following failure to pass the pre-Transmission Assessment Survey of antigenemia prevalence, five districts completed two rounds of MDA using a three-drug regimen (Ivermectin, Diethylcarbamazine, and Albendazole; IDA) and achieved over 65% coverage of the total population in 2023 and 2024. An Epidemiological Monitoring Survey (EMS) was conducted to evaluate IDA's impact. A cross-sectional EMS was conducted 9 months post-MDA in 11 evaluation units (EUs) across five districts, using two sites per EU (n = 22). A total of 6,829 individuals aged ≥20 years were sampled via multi-stage methods, with ≥300 blood samples per site. Data on demographics and MDA participation were collected. LF antigen testing was followed by night blood microfilariae testing in antigen-positive samples. Analysis included non-parametric tests, logistic and mixed-effects models accounting for site-level clustering, and penalized regression (lasso and ridge) to assess predictor importance and manage multicollinearity. Nine of 11 EUs passed EMS. Two EUs in Kapilvastu failed due to ≥1% microfilariae prevalence in at least one site. Microfilariae prevalence was negatively correlated with site MDA coverage (p-value 0.04), but not antigen prevalence (p-value 0.8). Overall, 4.63% of participants were antigen-positive and 0.34% were microfilariae-positive (ratio 14:1). Being female (OR 0.12; 95% CI: 0.04-0.36) and participation in latest MDA round (OR 0.34; 95% CI: 0.15-0.77) were associated with lower microfilariae prevalence. Suboptimal impact of MDA was observed in two EUs based on microfilariae prevalence and may reflect insufficient treatment compliance. Two additional rounds of MDA with directly observed treatment are recommended to improve adherence. Female sex and participation in the most recent MDA round were associated with reduced odds of microfilaremia. Targeted strategies focusing on men and other identified risk groups may enhance program effectiveness.
Coexistence among sympatric primates is often maintained through differences in diet, activity budgets, vertical space use, and responses to environmental heterogeneity, yet these mechanisms remain insufficiently tested in regenerating forests. Because habitat loss and population decline threaten many primates, it is important to determine whether regenerating habitats can support viable populations while maintaining ecological differentiation among species. We integrated hydrological, habitat, and weather variables with observations of activity budgets and vertical space use to evaluate how mantled howler monkeys ( Alouatta palliata ), Central American spider monkeys ( Ateles geoffroyi ), and Panamanian white-throated capuchins ( Cebus imitator ) use forest habitats at La Selva Research Station, Costa Rica. Across 91 observation events involving 462 individuals, all three species were observed most often in old-growth forest and near minor rivers, indicating overlap in broad environmental contexts. Individual density estimates were high relative to published values for howler monkeys (32.8 individuals/km²) and spider monkeys (27.8 individuals/km²), whereas capuchin density (20.1 individuals/km²) was near the upper end of published ranges. Despite this overlap, species differed in behavior and vertical space use: howler monkeys were observed primarily resting and foraging and used both canopy and emergent strata, spider monkeys traveled most frequently and concentrated in the canopy, and capuchins showed mixed activity patterns while also using the canopy most often. These findings indicate that regenerating forests can support substantial primate populations while preserving species-specific ecological strategies important to primate coexistence.
Tropical forest restoration is an important nature-based solution that can sequester carbon as a means to mitigate climate change. Restoration approaches range from natural regeneration to intensive tree planting, but few studies have compared aboveground biomass (AGB) stocks over decadal time scales across multiple restoration treatments implemented at the same sites. Here we leverage data from a two-decade restoration experiment in southern Costa Rica; in 2004-2006, we established restoration plots representing a gradient of intervention intensity: natural regeneration (no planting), applied nucleation (planting tree clusters), and plantation (full planting). We compare 18-20 years of AGB across treatments of the four planted tree species and naturally recruited trees. We also examine the relationships between AGB pools and structural metrics derived from UAV-borne LiDAR data collected after 16-18 years. Because most AGB was in planted trees, AGB was about 6.5 times greater in plantations compared to natural regeneration, and double in plantations compared to applied nucleation after two decades, despite substantial mortality of planted trees. However, the plantation treatment suppressed naturally recruited AGB and accumulated only half the amount of the natural regeneration treatment. Natural recruits comprised four times the proportion of AGB in applied nucleation compared to plantation. LiDAR-quantified LAI was more tightly correlated with total AGB in natural regeneration plots, whereas canopy height was more strongly correlated with planted biomass in plantation and applied nucleation. Our results highlight that tree planting accelerates AGB accumulation at degraded sites and illustrate that practitioners should select species with complementary life history strategies that enable carbon to be sequestered beyond the first decade. Given the tradeoff between planted tree biomass and naturally recruited biomass, spatially patterned methods that plant fewer trees may better balance restoration goals beyond carbon accumulation, leading to more structurally and biologically diverse reforested systems.
Agricultural expansion creates mosaic landscapes where managed land borders undisturbed ecosystems, facilitating the ecological spillover of organisms between habitats. While fungal spillover from natural systems to crops is relatively well-studied, the reverse—agricultural fungi colonizing adjacent forests—remains underexplored. We investigated whether coffee fields act as reservoirs for foliar fungi that spill over into adjacent tropical forests, particularly affecting close relatives of coffee (Rubiaceae). Using transect-based field surveys, airborne spore sampling, and metabarcoding of fungal communities, we found that leaf spot incidence was much higher in coffee than in adjacent understory forest leaves and declined with distance into the forest for Rubiaceae plants. Pleosporales was the dominant fungal order in coffee leaves and declined in abundance with distance from the forest edge in both airborne samples and Rubiaceae leaves, suggesting propagule pressure from coffee fields led to changes in the phyllobiome of close coffee relatives in the adjacent forest. Among the 1,000 most abundant coffee-associated fungal taxa, 19 declined with distance into the forest, and 93 were more abundant on phylogenetically close relatives of coffee compared to non-Rubiaceae plants. Several of the closest matches for these taxa were potential plant pathogens. These results demonstrate that high-density crops can act as reservoirs for fungi capable of colonizing adjacent forest plants, disproportionately affecting plants closely related to the crop. This appears to disrupt natural plant pathogen dynamics in forests such that close relatives of the crop plant near the crop-forest border face increased disease pressure and may be at a competitive disadvantage as a result. These findings highlight an underappreciated edge effect of agriculture in fragmented landscapes.
