Forest restoration after severe degradation by coal mining: lessons from the first years of monitoring

Abstract

Restoration after mining often requires strong interventions, including soil reconstruction, which makes vegetation establishment a challenge. We analyzed regeneration of woody plant species in the first years of restoration in areas severely degraded by coal mining in the south Brazilian Atlantic rainforest. At the four restoration sites, we collected data on cover of the herbaceous layer (including invasive grasses) and on abundance and richness of introduced trees and of spontaneously establishing woody plants. We also evaluated soil chemical features at all sites. We compared functional characteristics of the woody regeneration with nearby forest remnants (target communities) and evaluated the dynamics of regeneration over 3 years by principal coordinates analyses. The influence of biotic and abiotic variables for the regeneration of woody species was analyzed by partial redundancy analysis. We found high variation in community composition and structure among restored sites. Most of this variation was explained by variables related to soil chemistry and introduced trees. Over time, an increase in woody species establishment could be observed, and woody species communities appear to be at the start of trajectories toward target communities. Fertilization of soil, as commonly applied in restoration, seems to increase cover of exotic grasses, which clearly impedes the development of planted trees and woody species regeneration. Although the restoration of abandoned mining areas is a challenge due to the severe degradation, our results—despite the short period of observation—allow for the conclusion that restoration is possible, even with high initial costs. We highlight the importance of monitoring the initial process of restoration and of (re)defining intermediate goal and project targets, following an adaptive management approach. © 2018, Botanical Society of Sao Paulo.