Key plant indicators for monitoring areas undergoing restoration : acase study at the Das Velhas River, southeast Brazil.

Abstract

tIn restoration ecology, the search for key variables which allows an informative and concise diagnosison areas undergoing restoration is still a challenge. Choosing which indicators to use is a fundamentaldecision when proposing monitoring of any restored area. Here, we have aimed to contribute with theselection of key indicators by identifying plant parameters that are useful to assess restored areas inusing a 5-year-old rehabilitated riparian forest as a case study. Initially, we used 14 descriptors to assessthe ecosystem attributes of structure, diversity and ecological processes, and then we conducted a modelselection to identify variables that best explained the restoration success (defined as the richness of nativetree species). Our final model contained six parameters: native tree species (the response variable), nativeand exotic species of other life forms, basal area, tree density, and canopy openness) and an adjusted R2of 92%. As the predictive model doesn’t contain variables related to ecological processes, we includedseedling recruitment or litterfall production to evaluate this attribute. The selected indicators evidencedthat the tree layer has yet to develop and accumulate biomass, the forest has been enriched by speciesof other life forms (although many of them were exotic and invasive), and exotic tree and shrub specieswere dominating seedling recruitment. Such a scenario is likely to occur because the forest is locatedin an anthropogenic region, and highlights the importance of conserving remnant areas as propagulesources. We suggest some managing actions for the area, and conclude that not all measured indicatorswere necessary to facilitate good vision about the studied forest (because many had collinear responses),which may be important for directing other monitoring projects and save time and money.