Ecological Restoration of Pantanal Wetlands

Abstract

Degradation affects approximately three-quarters of the global wetland area. Depending on degradation drivers, resilience level, and environmental filters, different ecological restoration techniques are recommendable. The scope of this chapter is broadening the current analysis of the restoration effort made in Pantanal wetlands. We intended to include all available restoration studies in the Pantanal and discuss current public policies. In this context, we firstly reviewed restoration studies worldwide pointing some trends and gaps in wetlands. Then, focusing on the Pantanal, we discuss a recent map of the Brazilian biomes showing areas of low and high resilience, the latter being faster to restore. Next, we show a synthesis of our studies on active and passive restoration conducted in the Pantanal plain and surrounding uplands. We warn that a previous diagnosis for restoration is crucial to choose proper techniques related to resilience level. In a 2-month flood simulation trial, all 13 studied species survived, and only two had decreased root biomass, height, and diameter. Passive restoration (i.e., natural regeneration) of degraded areas after clearing (axe-logging and burning) in the Nhecolândia subregion, considered as a “high-resilient” site, takes 30 years; it is the cheapest and most efficient method if there is resilience. In contrast, direct sowing of ten tree species was ineffective, owing to inefficient pre- and post-sowing control of competitive exotic grasses, with only ten plants/ha of three species at 16 months after sowing; the tallest was Sterculia apetala (2–3 m) compared with Dipteryx alata and Vitex cymosa (1.3 m each). A third experiment focused on transplanting seedlings of four riparian species (Attalea phalerata, Inga vera, Ocotea diospyrifolia, and Psychotria carthagenensis). They had 0–80% survival after 8 months of flood, depending on species, seedling size-class, flood levels of collecting or planting points, and anti-herbivory protection; tree shelters highly increased survival. Finally, another study tested nucleation with topsoil transfer and artificial perches; the first species to fruit were Croton urucurana and Trema micrantha. Examples shown can be useful for planning, implementation, and monitoring ecological restoration in the Pantanal, as well as for understanding new challenges and opportunities.KeywordsDegraded areaInundation tolerancePeriodic floodingPlant successionRestoration ecologyVegetation