Catchment-scale forest restoration is expected to promote the recovery of tropical stream ecosystems by improving habitat conditions, channel structure, and, ultimately, biodiversity and ecosystem functioning. However, empirical evidence linking forest restoration to stream ecosystem benefits in the tropics remains limited. Here, we evaluated how stream habitat, water quality, and aquatic communities respond along a gradient of forest restoration in catchments previously dominated by pasturelands.
We sampled 30 independent headwater streams (150 m reaches) during the driest season (July 2023), representing six forest cover stages (N = 5 per stage), ranging from active pasturelands to mature forests. In each stream, we assessed physical habitat structure and water quality. Benthic invertebrates were sampled using a 0.25 mm mesh D-net, with each composite sample consisting of six habitat-proportional subsamples (1 m × 0.25 m each). Periphyton biomass, chlorophyll-a concentration, and community composition were quantified using acetate sheets.
Streams draining remnant and older restored forests exhibited lower water temperatures and nutrient concentrations, alongside higher habitat heterogeneity, compared to streams in pasture-dominated catchments. Invertebrate richness and the abundance of sensitive taxa (Ephemeroptera, Plecoptera, and Trichoptera – EPT) increased consistently with forest cover and restoration age. In contrast, periphyton chlorophyll-a, biomass, and taxonomic richness were highest in pasture streams and declined toward more conserved catchments. Functional composition of both invertebrate and periphyton communities also shifted along the restoration gradient, indicating changes in resource availability and ecosystem processes.
Overall, our results reveal a clear gradient of stream ecosystem recovery associated with forest restoration, encompassing improvements in water quality, habitat complexity, and biological communities. While structural attributes and water quality responded relatively rapidly, changes in invertebrate abs periphyton communities suggest a more gradual reorganization. These findings highlight both the benefits and temporal limitations of tropical forest restoration for stream health and reinforce the importance of long-term, catchment-scale approaches for freshwater ecosystem recovery.