Seasonal Pantanal Flood Pulse: Implications for Biodiversity Conservation – A Review

Abstract

The Pantanal is fed by tributaries of the Upper Paraguay River in the center of South America, mainly in Brazil. The landscape is marked by contrasts between the seasonally floodplain (Pantanal) and the surrounding highland (Planalto). The floodplain regulates highland riverine discharge by temporarily storing water during flood season and can enhance water loss by evapotranspiration and infiltration. The flood level gradient creates a range of major habitats in a complex mosaic of annual and pluri-annual seasonal patterns. The Pantanal ecosystem is characterized by recurrent shallow water flooding near the surface of the substrate, due to the slow drainage of the vast plain inundated for longer, with variable conditions regarding to physical, chemical, and biological traits. Water discharge, geomorphology, type of soil and biodiversity are the main ecosystem components of the Pantanal. The complex vegetation cover and the seasonal productivity support a diverse and abundant fauna. Many endangered species still occur in health population conditions, including jaguar (Panthera onca). Waterfowl are exceptionally abundant during the dry season. Deforestation with the loss of natural habitats and their associated biodiversity in the Pantanal has been drastic during the last decades, particularly in the upland region of the Cerrado plateaus surrounding the flooding plain. Another threat is unsustainable agricultural and cattle ranching practices, which convert the natural vegetation into pastures and plantation crops such as soybean, especially on the surrounding plateaus where the river springs are located. Fires caused by humans are severe and have become part of the annual productivity cycle for cattle ranch owners. Recently there has been river flow modification due to implantation of small hydroelectric plants on the upland plateaus. The aim of this study is to put together a comprehensive report on the role of the flood pulse on the biodiversity using our research experience in the region and also reviewing published information.

Effects of flooding and its temporal variation on seedling recruitment from the soil seed bank of a Neotropical floodplain

“…Our results are novel in that they indicate that flooding provides favorable conditions for an increase in species richness and abundance in seedling recruitment soon after water had receded. These findings support the general conception that seasonal flooding is essential for the Pantanal (Alho & Sabino 2012;Pott & Silva 2015). The fact that the highest seedling richness and abundance in PF (post-flooded) …”

“…Cycles of fl ood and drought, (i.e., the temporal and spatial variation in water level) infl uence the availability of habitats with the conditions necessary for seedling establishment, thereby allowing the occurrence of species with diff erent life-strategies for the various phases of the hydrological cycle (Valk 2005). Changes caused by annual and recurrent fl ooding can result in plant adaptations that can increase species diversity; therefore, a high level of biodiversity adapted to diff erent conditions can be expected in fl oodplains (Alho & Sabino 2012;Pott & Silva 2015). Th erefore, annual and perennial species can be expected in such environments, either as adults, juveniles, seeds or as other viable propagules, thereby maintaining diversity (Valk 1981).…”

Assessment of Avian Occurrence in the Brazilian Chaco

“…Among the omnivores, the combination of terrestrial and hydric habitats favor the offer of invertebrate preys, amphibians and fish, depending on the annual seasonality. 31 We found 32.6% of omnivore species. Our results show that the majority of the species occurrence was found in open areas (n=130; 39.9%), and the other portion occurs in generalist habitats: forest, open areas and modified habitats (n=87; 26.7%), only in forest (n=44; 13.5%), and in aquatic areas (n=65; 19.9%).…”

Hidden in plain sight: How finding a lake in the Brazilian Pantanal improves understanding of wetland hydrogeomorphology

“…active tectonics). The maximum inflow discharge inside the wetland normally occurs one to two months after the beginning of the rainy season near the catchment area, and up to five months in the southern portion ( Figure 1D) (Fantin-Cruz et al, 2011;Alho and Sabino, 2012;Assine et al, 2015c). meandering, distributary, and anabranching patterns) that control the interplay of the depositional systems (Assine et al, 2015a).…”