The legal protection of the Brazilian Atlantic Forest, a biodiversity hotspot (Myers et al., 2000), is defined by the Federal Law 11,428/2006, regulated by the Decree 6660/2008. The Atlantic Forest Act (hereafter AFA) defines guidelines for the use and conservation of native vegetation of the Atlantic Forest, the only Brazilian biome protected by specific legislation. The AFA establishes that the suppression of vegetation at advanced and intermediate stages of regeneration is allowed only in cases of public utility and social interest (Araujo, 2010). In both cases, suppression is authorized after an environmental compensation proposal is issued, which consists in the protection of a like-to-like area in the same river basin. Secondary vegetation classified at initial regeneration stages is not protected by the AFA and can be deforested without compensation (Ribeiro et al., 2009).

The AFA encompasses the Atlantic Forest sensu stricto and associated ecosystems, including open vegetation types such as the campo de altitude (altitudinal grassland) and the campo rupestre (Scarano, 2002; Neves et al., 2017, 2018). To improve the applicability of the AFA, the Brazilian National Environment Council (CONAMA) published the Resolution 423/2010 (hereafter CR423; see Supplementary Material I) defining the specific parameters and criteria for seral classification of campo de altitude vegetation, including lists of indicator plant species in each regeneration stage. Based on the principle of analogy (Kelsen, 2006), environmental agencies have been employing the CR423 for environmental licensing in campo rupestre areas, despite strong geological and floristic differences with the campo de altitude (Alves and Kolbek, 2010; Vasconcelos, 2011). There is vast literature discussing features of these two vegetation types (Scarano, 2002; Benites et al., 2007; Alves and Kolbek, 2010; Vasconcelos, 2011), and therefore we do not address this subject here.

The AFA encompasses the Atlantic Forest sensu stricto and associated ecosystems, including open vegetation types such as the campo de altitude (altitudinal grassland) and the campo rupestre (Scarano, 2002; Neves et al., 2017, 2018). To improve the applicability of the AFA, the Brazilian National Environment Council (CONAMA) published the Resolution 423/2010 (hereafter CR423; see ) defining the specific parameters and criteria for seral classification of campo de altitude vegetation, including lists of indicator plant species in each regeneration stage. Based on the principle of analogy (Kelsen, 2006), environmental agencies have been employing the CR423 for environmental licensing in campo rupestre areas, despite strong geological and floristic differences with the campo de altitude (Alves and Kolbek, 2010; Vasconcelos, 2011). There is vast literature discussing features of these two vegetation types (Scarano, 2002; Benites et al., 2007; Alves and Kolbek, 2010; Vasconcelos, 2011), and therefore we do not address this subject here.

Campo rupestre is an ancient, heterogeneous vegetation mosaic established on quartzite and ferruginous rocks in the highlands of Brazil. Despite harboring the highest levels of plant diversity and endemism in the country (Giulietti et al., 1997; Silveira et al., 2016), hard-policies to protect this ecosystem are inexistent. We aimed to investigate the effectiveness of the current legal protection of this environment by scrutinizing scientific evidence that underpins the application of the CR423 for campo rupestre. We investigated if the criteria used for campo de altitude is applicable for campo rupestre by answering the following: (1) What is the degree of similarity between the campo de altitude indicator species listed in CR423 and the campo rupestre flora? (2) Does the seral classification for campo rupestre fit similar assumptions as established by CR423 for campo de altitude? and (3) How has environmental compensation been carried out by projects legally licensed in areas of campo rupestre under AFA?

We found that the application of the AFA to environmental licensing in campo rupestre lacks a scientific basis. First, there is little overlap between the list of indicator species in CR423 and the campo rupestre flora. Second, empirical evidence to support vegetation classification into successional stages is lacking. Therefore, the current guidelines and parameters established by legislation are inappropriate for campo rupestre conservation and management. We suggest that legislation misapplication in the environmental licensing process is resulting in biodiversity loss.

Indicator species in CR423 poorly represents the campo rupestre flora. Due to the low floristic similarity between campo de altitude and campo rupestre (Alves and Kolbek, 2010), the use of this legal instrument as a criterion for suppression and compensation in campo rupestre is technically impracticable. Despite its small geographic extent, campo rupestre is a highly heterogeneous ecosystem driven by edaphoclimatic factors (Abrahão et al., 2019). The resulting plant communities have dissimilar composition, and geographically structured endemism (Echternacht et al., 2011; Messias et al., 2011, 2012; Carmo and Jacobi, 2016; Neves et al., 2018). Therefore, the strong species turnover among campo rupestre sites poses a challenging task to establish lists of indicator species (Neves et al., 2018).

The process of ecological succession established by the CR423 has proven inappropriate to guide licensing and compensation in campo rupestre. Our data showed that no study investigated chronosequences of secondary succession in campo rupestre, and this lack of scientific knowledge hampers the development of practical criteria and parameters to classify seres. In the well-known process of forest regeneration, early stages of succession are characterized by low species and functional diversity, low biomass, habitat complexity, canopy cover and high environmental stress (Chazdon, 2008). During succession, as ecosystem development occurs, the structure, function and composition of regenerating forests become more similar to pre-disturbance, old-growth forests (Guariguata and Ostertag, 2001). This textbook mode of succession is called progressive succession, which culminates in the phase of maximal biomass accumulation (until further disturbances or soil limitation takes place; Wardle et al., 2004; Fig. 2).

Fig. 2.

Theory of ecosystem retrogression (modified from Walker and Reddell, 2007). Secondary succession is applied to forests whereas the retrogressive phase best characterize succession in campo rupestre. The fundamental differences in secondary and retrogressive succession are shown in the boxes above the draws, but the Y-axis depicts changes in aboveground biomass as an example to illustrate different properties between the two processes. The green arrows indicate the trajectory of succession with time.

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Progressive succession strongly contrasts with less-known retrogressive succession (Walker and Reddell, 2007). The retrogressive phase of succession is common in ecosystems establishing on old and extremely-impoverished soils (Walker and Reddell, 2007). Conversely to secondary succession, ecosystem retrogression is characterized by a decline in soil nutrient availability, reduction in biomass and plant productivity, and increasing predominance of slow-growth and stress-tolerant species (Gaxiola et al., 2010; Coomes et al., 2013). Differently from the progressive succession, retrogression is a phenomenon that occurs on a scale of (tens or hundreds of) millennia (Walker and Reddell, 2007; Peltzer et al., 2010; Fig. 2). Anthropogenic disturbances including soil removal, nutrient inputs or changing fire regimes do not take ecosystems in the retrogressive phase to an earlier stage that tends to recover toward the previous state (such as occurs in the progressive succession). Instead, these processes accelerate the retrogression leading to ecosystems with lower biomass and complexity, further reducing resilience (Walker and Reddell, 2007; Peltzer et al., 2010). Ecosystems in the retrogressive phase do not seem to recover to their previous states not even with the help of restoration efforts (Peltzer et al., 2010). In addition, there is theoretical and empirical evidence on the low resilience and the lack of regeneration in campo rupestre following degradation (Buisson et al., 2019; Le Stradic et al., 2018), as expected for an ecosystem in retrogression.

The model of retrogressive succession applies to campo rupestre (Abrahão et al., 2019), and therefore, the application of successional stages in AFA is inappropriate to license projects in campo rupestre areas. Nevertheless, almost half of the environmental licensing processes analyzed classified campo rupestre areas in some stage, despite the lack of scientific criteria underpinning such classification. Unfortunately, the criteria used to define the successional stage were predominantly that related to the degree of human impact in the area, which has no strict relation to ecological succession (Prach and Walker, 2019).

Finally, all licensing processes that requested permission to suppress campo rupestre areas were located within the limits of the Atlantic Forest. Hence, the environmental agencies required environmental compensation as recommended by AFA. Although the data referring to 35% of the compensation proposals were unavailable, our results show that extensive campo rupestre areas were legally lost by mining through out-of-kind, rather than a like-to-like compensation (Sonter et al., 2014). In view of the impossibility to recover campo rupestre areas (Le Stradic et al., 2018), the like-to-like compensation becomes important strategy to conciliate exploration and conservation.

Given the silent biodiversity loss in areas with irreplaceable ecosystem services (e.g. water supply, Rodrigues et al., 2019), we suggest the formulation of specific legislation to improve environmental licensing in campo rupestre is needed to reconcile natural resource exploration and conservation (Box 1). We acknowledge that, in the absence of specific legislation, the use of the AFA in project licensing is better than no regulation at all (see Vasconcelos, 2014). However, laws inappropriate to meet the need for conservation and sustainability should be adjusted (Howes et al., 2017; Singh et al., 2018). We argue for a broad, comprehensive, evidence-based discussion in order to produce sound legislation that will recognize the need for sustainable use of natural resources in campo rupestre. Such initiative will bridge the gap between science and practice, and will likely advance our ability to prioritize areas for exploration and better target sites for conservation of biodiversity and ecosystem services, benefiting society, people and nature.

None.