Restoration in the Cerrado: savannah is different from forest and preserving its particularities is crucial for climate resilience
Afforestation practices adopted in the Atlantic Forest can lead to harmful and inefficient results for the maintenance of ecosystem services in Brazil's second largest biome: the Cerrado.
By Consórcio Cerrado das Águas
Brazil is home to an extraordinary wealth of biomes, each with unique characteristics and vital importance for the preservation of biodiversity, resources and natural cycles. The Cerrado and the Atlantic Forest are recognized worldwide for their biological diversity and the ecosystem services they offer. However, the Atlantic Rainforest, due to its geographical position and also its history, has been exploited since the beginning of colonization, in view of the Pau brasil, a species of great economic interest that almost went extinct.
With this history, the restoration processes known in Brazil are always mirrored in the way of restoring this biome, which is made up of trees and has a process of succession between them. Restoration techniques consolidated for the Atlantic Forest were, for a long time, directed towards the Cerrado. By generalizing restoration practices for the two biomes, the Cerrado does not achieve effective reforestation and restoration. Brazil's second largest biome and the cradle of its waters plays a fundamental role in biodiversity conservation and has a major challenge: to circumvent climate threats while facing the great prejudice of being a Savannah and without having to transform itself into a large forest.
Atlantic Rainforest vegetation
The question is how this should be done and, to this end, the Cerrado Waters Consortium (CCA) spoke to two professionals specializing in restoration in the Cerrado to broaden the perception of the paths that need to be adopted for this purpose.
"In the Cerrado there are forest areas, gallery forests, dry forests and others, which are similar to the Atlantic Forest, but when it comes to grasslands and savannas they are completely different ecosystems. In forests the limiting resource is light, in the Cerrado it is water and nutrients in the soil. In forests there should be no fire, in grasslands and savannas fire is essential to maintain the diversity and functioning of ecosystems. In forests, the biomass and carbon are in the tree trunks. In grasslands and savannas, the biomass is more in the roots and the carbon is in the soil. The regeneration of forest plants is mainly through seeds, while in grasslands and savannas it is through the regrowth of roots, among other particularities. These are very different ecosystems which, if treated in the same way to plan restoration, will certainly fail and waste resources," explains Alexandre Sampaio, a forestry engineer with a PHD in Ecology and an environmental analyst at ICMBio (Chico Mendes Institute for Biodiversity Conservation).
For the researcher, the first factor to understand is that grasslands and savannas are characterized by a continuous stratum of low plants, such as grasses, and it is in this stratum that the diversity of plants responsible for much of the ecosystem's functioning, carbon sequestration and infiltration of water into the soil is found. Alexandre warns about the approach to restoring the Cerrado by planting trees alone. "There are trees in the savannas, but if we only plant trees, we're not restoring the original ecosystem, we're losing the most important layer of small plants. In the grasslands and savannas, the seeds are less important for regeneration, many are empty and non-viable, so seed dispersal is small and natural regeneration by seeds is low, but if the grasslands and savannas are cleared without disturbing the soil, the roots are capable of bringing back all the plant diversity," he considers.
Reforestation in the Cerrado and the misconception of "afforestation"
Unlike the Atlantic Forest, where restoration often involves planting large trees, the Cerrado is characterized by lower and sparser vegetation, made up of grasses, shrubs and smaller trees. Therefore, reforestation of the Cerrado requires an approach adapted to its specific characteristics. The use of seeds and seedlings of species native to the Cerrado is fundamental for the reintroduction of the original vegetation. In addition, the creation of ecological corridors and the promotion of connectivity between preserved areas are important strategies for the successful restoration of the Cerrado, allowing the flow of species and the recovery of fragmented habitats.
The main misconception that occurs, as absurd as it sounds, is when restorers look at fields and savannahs that have been converted to agriculture and pasture and decide to just plant trees in an attempt to plant forests. If forest trees are planted there, they won't be able to reproduce due to the dry season and, if they do manage to develop, there's a good chance they'll die when a fire breaks out, which is very likely because the growth of the trees will hardly form a canopy capable of eliminating the exotic grasses, which are excellent fuel for fire. Even worse, but just as common, is when people with no local knowledge look at an area of native grassland where there are naturally no trees and decide to plant trees there. In order to plant these trees, which will probably die over the years, it will be necessary to uproot native plants, always causing more impact than benefit. Such ignorance seems unlikely, but it continues to happen in various parts of the Cerrado, a phenomenon that even has a name: afforestation," says Alexandre.
Dr. Giselda Durigan, a researcher at the Environmental Research Institute of São Paula, says that in the Cerrado, trees should be supporting rather than dominant species, because the Cerrado has a structure characterized by sparse trees and a low stratum dominated by grasses covering the ground. For her, if the Cerrado is transformed into a large forest area, with a so-called succession area, there will be negative consequences.
"If (forest) densification takes place in the Cerrado, the negative consequences for the biome will be dramatic in terms of the loss of endemic species of flora and fauna and, in addition, the main ecosystem service associated with savannah vegetation will be severely compromised, which is the recharge of groundwater reserves and the supply of springs and rivers in most of Brazil. This would happen because forests intercept around 30% of the rain in their canopies and remove much more water from the soil than the open vegetation of the Cerrado," says the researcher.
Cerrado Vegetation
Connecting landscapes: an effective path to restoration
Deforestation in the Cerrado once again triggered a red alert in the first half of 2023. The total number of deforestation alerts rose by 21% in this period, equivalent to 4,408 km², according to data released by the Real-Time Deforestation Detection System (Deter). On the contrary to the alarming figures, there are actions aimed at adequate reforestation that bring hope for the conservation of this important biome. One of these actions is landscape connectivity, linking the remaining natural areas of the Cerrado. However, there are challenges that need to be overcome for this to happen, as Giselda says.
"Connectivity between remaining areas depends on the land use that separates them. The less similar the structure of the cultivated vegetation is to the structure of the savannah vegetation (sparse woody plants over the grassy undergrowth), the more severe the isolation will be. Agriculture is the most hostile matrix, i.e. the one that most strongly isolates the remnants of the Cerrado. At the other extreme are pastures that have not been intensified. If there are pastures with sparse trees and shrubs between the remnants, it can be considered that the Cerrado fragments are still connected for most of the fauna (birds, mammals, reptiles, ants and even invertebrates) and flora. The fauna continues to use the pastures as a source of food and habitat, and the native plants in the pastures act as stepping-stones for pollinators and seed dispersers. Forestry is less friendly than pastures, but it's much less hostile than agriculture, especially because it maintains understory in the Cerrado and because it takes place over much longer periods of time," he says.
Landscape connectivity has been one of the work fronts of the Cerrado Waters Consortium since 2019 with the PIPC (Conscious Producer Investment Program). Operating in three river basins in the Cerrado Mineiro region, the Consortium works with rural producers to conserve and restore native vegetation on their properties. The need for restoration and conservation actions is one of the PIPC's main factors, since they have the greatest impact on ecosystem services, especially conservation. In all, hectares of native forest are in the process of being restored. For the CCA's Executive Secretary, Fabiane Sebaio, understanding the dynamics of the Cerrado and the techniques for restoring savannas are essential for maintaining the title of Cradle of Waters, the name given to the Cerrado because it is the biome that supplies Brazil's three major river basins.
For researcher Giselda, there are possibilities for seeking a friendlier landscape in the Cerrado to minimize the consequences of fragmentation and, to this end, she makes two main recommendations: maintain (or restore) the permanent preservation strips with native vegetation and this includes not only riparian forest, but also wet fields, veredas, and even some open Cerrado vegetation; and connect the remaining fragments to each other and to the riparian zone through pasture corridors or restored vegetation with a savannah structure (sparse trees and shrubs and a low stratum predominantly made up of native grasses), concludes Durigan, who has been studying restoration in the Cerrado for over 30 years.
"It is known that the native vegetation of the Cerrado has roots that capture water at great depths, underground stems that store water, as well as thick leaves with the presence of hairs that reduce water loss. We associate the Cerrado's roots with real sponges, because when it rains they take the absorbed water to the water table. That's why turning the Cerrado into a large forest will do great harm. When Cerrado vegetation is replaced by plants with smaller roots, it affects water resources," concludes Mariana Cristina, CCA's connected landscapes analyst.
About the CCA
Created in 2015 in Patrocínio, Minas Gerais, the Cerrado Waters Consortium aims to join forces to implement strategies that guarantee the provision of ecosystem services in order to achieve a productive system that is resilient to climate change.
The initiative has the following companies as associate members: Nescafé, Expocaccer, Nespresso, Lavazza, Cooxupé, CofCo, Volcafé, Stockler, Daterra, Federação dos Cafeicultores do Cerrado and CerVivo. In addition, the platform has key partners such as Serra do Salitre City Hall and Coromandel City Hall.
Find out more at: http://cerradodasaguas.org.br