Lower-intensity restoration interventions drive greater seedling establishment for later-successional tree species

Recovery of tree community composition in restored tropical forests relies on successful recruitment of later-successional species. However, the long-term effects of different restoration interventions on establishment success of arriving seeds are poorly understood. We evaluated the effects of three restoration treatments on the seed-to-seedling transition for later-successional tree species in a fragmented agricultural landscape in southern Costa Rica. Restoration plots (0.25 ha) were established in a block design nearly two decades prior and spanned a gradient of intervention intensity: natural regeneration (not planted), applied nucleation (planted tree clusters), and plantation (fully planted). We conducted seed addition experiments from 2021-2023 using eight species at seven replicate restoration sites and in four nearby remnant forests., Study region
We conducted this study from June 2021 to September 2023 in southern Costa Rica near Las Cruces Biological Station. The forests in this region are at the boundary between Tropical Premontane Wet and Rain Forest zones (Holdridge et al., 1971), and the study sites range from ~1100 to 1200 m in elevation. Soils are volcanic in origin, mildly acidic (pH ~5.5), low in P, and high in organic matter. Mean annual temperature is ~21°C, and annual precipitation is between 2700 and 5000 mm, with a dry season from December to March. The landscape was largely deforested between 1960 and 1980 and is now a fragmented mosaic of remnant forest, secondary forest, cattle pastures and agricultural fields.
Design of long-term restoration experiment
We used seven restoration sites set up in 2004-2006 (Figure 1), a subset of the 15 sites described in Holl et al. (2020). All sites were previously used for ≥ 18 years for grazing or coffee production, and most are steeply sloped (15-35º). Minimum di..., # Data from: Lower-intensity restoration interventions drive greater seedling establishment for later-successional tree species

Dataset DOI: [10.5061/dryad.cfxpnvxjp](10.5061/dryad.cfxpnvxjp)

## Description of the data and file structure

Data from a field experiment in which seeds of eight later-successional tree species were added to restoration plots and remnant forests in southern Costa Rica to assess barriers to seedling establishment.  
### Files and variables

#### File: canopy\_cover.csv

**Description:** canopy cover above each seed addition quadrat, calculated from four densiometer measurements

##### Variables

* plot_id: (character) Unique identifier for each plot, combining site and treatment (see below).
* site: (character) two-letter code identifying each study site
* treatment: (character) two-letter code for treatment. NR = natural regeneration, AN = applied nucleation, PL = plantation, RF = reference forest
* station: factor (integer 1-4) identifying the set of plots...,