Understory frog communities recover quickly during tropical forest regeneration

This dataset contains plot-level data on understory frog communities sampled along a forest regeneration chronosequence in the lowland Chocó forest near Hoja Blanca, Esmeraldas province, northwestern Ecuador. Sampling was conducted within and around the privately managed Canandé (14,000 ha) and Tesoro Escondido (1,800 ha) reserves. A total of 38 plots (50 × 50 m; 2,500 m²) were established across a mosaic landscape, including active pastures (n = 6), active cacao plantations (n = 6), regenerating forests following pasture or cacao abandonment (0–37 years; n = 18), and old-growth forest (n = 8). Plots ranged from 159 to 615 m a.s.l. Regeneration time was determined from local land-use history records and reserve acquisition data. Understory frogs were surveyed using standardized visual encounter surveys with two person-hours per plot per visit. Each plot was sampled six times between March 2022 and June 2023, including both day and night sessions. Species abundances were pooled across visits to obtain one value per species per plot. The dataset includes (a) species abundance data per plot, and (b) associated environmental predictors, including regeneration time, land-use legacy (cacao or pasture), elevation, basal area, distance to the nearest forest older than 40 years, and proportion of surrounding forest older than 40 years within a 500 m radius. The repository also includes the R script used for statistical analyses.

Methods
Study area and sampling design

Fieldwork was conducted in the lowland Chocó forest near Hoja Blanca, Esmeraldas province, northwestern Ecuador, within and around the privately managed Canandé (14,000 ha) and Tesoro Escondido (1,800 ha) reserves (0.52°N, 79.2°W; 130–615 m a.s.l.). The landscape consists of a mosaic of old-growth forest, secondary forests of different ages, pastures, and cacao plantations.

A total of 38 plots (50 × 50 m; 2,500 m²) were established following a space-for-time substitution approach (chronosequence). Plots were distributed across active pastures (n = 6), active cacao plantations (n = 6), regenerating forests after pasture or cacao abandonment (0–37 years; n = 18), and old-growth forest (n = 8). Regeneration time for secondary forests was determined from local land-use history records and reserve acquisition information. Old-growth forest plots were not assigned a regeneration age.

Plots were spatially distributed as widely as possible within habitat categories (minimum distance = 184 m; maximum distance = 14 km).

Frog surveys

Understory frogs were sampled using standardized visual encounter surveys. Each plot was surveyed for two person-hours per visit, scanning from leaf litter up to approximately 1.2 m above ground. Each plot was visited six times between March 2022 and June 2023, across three sampling rounds that included both day and night sessions.

All individuals encountered were captured, identified to species level, and released. Species abundances were pooled across the six visits to obtain one abundance value per species per plot.

Environmental predictors

Plot-level environmental variables included regeneration time (years since abandonment), land-use legacy (cacao or pasture), elevation (m a.s.l.), distance to the nearest forest older than 40 years (m), and proportion of forest older than 40 years within a 500 m radius. 

Data processing

Species abundances were pooled across visits to reduce seasonal and stochastic variation in detection. The accompanying R script contains the code used to calculate diversity metrics and perform statistical analyses based on the data provided.