Restoration in the Cerrado: savanna is different from forest.

Why reforestation practices from the Atlantic Forest don't work in the Cerrado.

Atlantic Forest vegetation

Understanding the differences between the Cerrado (savanna) and the Atlantic Forest (forest) is essential to ensure the effectiveness of the restoration of the Cerrado and the entire Brazilian biome.

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 Forest, due to its geographical position and history, has been exploited since the beginning of colonization, as evidenced by the Brazilwood, a species of great economic interest that almost became extinct.

With this history, the restoration processes known in Brazil are always modeled on the way this biome is restored, which is composed of trees and has a succession process among them. These restoration techniques, consolidated for the Atlantic Forest, were, for a long time, directed towards the Cerrado. By generalizing restoration practices for both biomes, the Cerrado does not achieve effectiveness in reforestation and restoration.

Brazil's second-largest biome and cradle of waters plays a fundamental role in biodiversity conservation and faces a major challenge: overcoming climate threats while confronting the widespread prejudice of being a savanna, without necessarily transforming into a large forest.

The question is how this should be done, and to that end, the Cerrado das Águas Consortium (CCA) spoke with two professionals specializing in Cerrado restoration to broaden the understanding of the paths that need to be taken to achieve this goal.

“In the Cerrado there are forest areas, gallery forests, dry forests and others, which resemble the Atlantic Forest, but when we deal with grasslands and savannas they are completely different ecosystems. In forests the limiting resource is light, in the Cerrado it is water and soil nutrients. In forests there should be no fire, in grasslands and savannas fire is essential to maintain the diversity and functioning of the ecosystems. In forests, biomass and carbon are in the tree trunks. In grasslands and savannas, biomass is more in the roots and carbon is in the soil. The regeneration of forest plants is mainly through seeds, in grasslands and savannas it is through root regrowth, among other particularities. They are very different ecosystems that if treated in the same way to plan restoration, there will certainly be failure and waste of resources.”

Explains Alexandre Sampaio, forestry engineer with a PhD in Ecology and environmental analyst at ICMBio (Chico Mendes Institute for Biodiversity Conservation). Biodiversity

According to the researcher, the first key factor is understanding that grasslands and savannas are characterized by a continuous layer of low-growing plants, such as grasses, and it is in this layer that the plant diversity responsible for a large part of the ecosystem's functioning, carbon sequestration, and water infiltration into the soil is found. Regarding the approach of restoring the Cerrado solely through tree planting, Alexandre issues a warning.

“There are trees in the savannas, but if we only plant trees, we are not restoring the original ecosystem; we will be losing the most important layer of small plants. In grasslands and savannas, seeds are less important for regeneration; many are empty and unviable, so seed dispersal is low and natural regeneration by seeds is poor. However, if the grasslands and savannas are cleared without disturbing the soil, the roots are capable of bringing back all the plant diversity,”

Alexandre points out.

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, sparser vegetation composed of grasses, shrubs, and smaller trees. Therefore, reforestation in the Cerrado requires an approach adapted to its specific characteristics.

The use of seeds and seedlings of native Cerrado species is fundamental for the reintroduction of the original vegetation. Furthermore, 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, however absurd it may seem, is when restorers look at fields and savannas that have been converted to agriculture and pasture and decide to simply plant trees in an attempt to create forests. If forest trees are planted there, they will not be able to reproduce due to the dry season, and if they do manage to develop, they have a high chance of dying when a fire occurs, which is very likely to happen, since the growth of the trees will hardly form a canopy capable of eliminating exotic grasses, which are excellent fuel for fire. Even worse, but also common, is when people without local knowledge look at an area of ​​native field where there are naturally no trees and decide to plant trees there. 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 improbable, but it continues to happen in various places in the Cerrado, a phenomenon that even has a name: afforestation,”

Analyzes Alexandre.

The researcher from the Environmental Research Institute of São Paulo, Dr. Giselda Durigan states that in the Cerrado, trees should be supporting actors and not dominant, because the Cerrado has a structure characterized by sparse trees and a base layer dominated by grasses covering the ground. According to her, if the Cerrado transforms into a large forested area, with what is called a successional area, there will be negative consequences.

“If deforestation occurs in the Cerrado, the negative consequences for the biome will be dramatic in terms of the loss of endemic flora and fauna species and, in addition, the main ecosystem service associated with savanna vegetation, which is the recharge of groundwater reserves and the supply of springs and rivers in most of Brazil, will be severely compromised. This would occur because forests intercept about 30% of the rain in their canopies and remove much more water from the soil than the open vegetation of the Cerrado,”

Assesses the researcher Durigan

vegetation of the Minas Gerais cerrado

Landscape Connectivity: An Effective Path to Restoration

Deforestation in the Cerrado has once again triggered a red alert in the first half of 2023. The total number of deforestation alerts increased by 21% during this period, equivalent to 4,408 km², according to data released by the Real-Time Deforestation Detection System (Deter). In contrast to these alarming figures, there are actions aimed at adequate reforestation that offer 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 explains.

"The connectivity between remaining areas depends on the land use that separates them. The less similar the structure of cultivated vegetation is to the structure of savanna vegetation (sparse woody plants over a grassy understory), the more severe the isolation. Agriculture is the most hostile matrix, that is, it is the one that most strongly isolates the remnants of the Cerrado. At the other extreme are pastures that have not been intensified. If pastures with scattered trees and shrubs exist among the remnants, it can be considered that the Cerrado fragments remain 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 existing in the pastures function as stepping stones for pollinators and seed dispersers. Silviculture is less friendly than pastures, but it is much less hostile than agriculture, especially because it maintains undergrowth in the Cerrado and because it occurs at much shorter intervals." "Long distances"

Giselda analyzes

Landscape connectivity has been one of the work fronts of the Cerrado das Águas Consortium since 2019 with the PIPC (Investment Program in the Conscious Producer). Operating in three hydrographic basins in the Cerrado Mineiro Region, the Consortium develops, together with rural producers, actions for the conservation and restoration of native vegetation on properties.

The need for restoration and conservation actions is one of the main factors of the PIPC, since they have the greatest impact on ecosystem services, especially those related to conservation. In total, hectares of native forest are in the process of restoration.

According to Fabiane Sebaio, Executive Secretary of the CCA, understanding the dynamics of the Cerrado and the techniques for restoring the Savannas is essential for maintaining the title of "Cradle of Waters," a name given to the Cerrado because it is the biome that supplies the three major hydrographic basins of Brazil.

For researcher Giselda, there are possibilities to seek a more environmentally friendly landscape in the Cerrado to minimize the consequences of fragmentation, and for this, she makes two main recommendations: maintain (or restore) permanent preservation areas with native vegetation, which includes not only riparian forests, but also wetlands, streams, and even a portion of open Cerrado vegetation; and connect the remaining fragments to each other and to the riparian zone through corridors of pasture or restored vegetation with a savanna structure (sparse trees and shrubs and a base layer predominantly formed by 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 hairs that reduce water loss. We associate the roots of the Cerrado with true sponges, because when it rains they carry the absorbed water to the water table. Therefore, transforming the Cerrado into a large forest will cause great harm. When the vegetation of the Cerrado is replaced by plants with smaller roots, it affects water resources,”

Concludes Mariana Cristina, connected landscape analyst at CCA.