Search

Mountains play a crucial role in the origin and maintenance of Neotropical biodiversity, but there are still unanswered questions about the diversification of the campos rupestres (CR), an herbaceous-shrubby sky-island vegetation in eastern South America. For orchids distributed across this disjunct rock habitat, difficulties with distinguishing morphological taxa add an additional challenge to disentangling the history of divergence. Here, we combined the power of ddRAD genomic data with broad sampling of Bulbophyllum sect. Didactyle (Orchidaceae), across the CR and other Neotropical outcrops, to estimate evolutionary relationships and evaluate the biogeography of the group’s diversification. Although genetic lineages generally align with geographic disjunctions, we also observe distantly related lineages within some previously recognized species. For such taxa, their lack of monophyly and a shared regional divergence pattern suggests a complex history that may include unrecognized diversity. When viewed through the lens of morphological variability, our study raises intriguing questions about the persistence and permeability of species barriers among orchid populations. These results, in addition to the recency of the divergence history of B. sect. Didactyle, provide insights about hypothesized community level vs. species-specific paths of diversification across the Neotropical sky-islands of the CR.

To achieve the ambitious goals of the UN Decade on Ecosystem Restoration, restoration frameworks should embrace the diversity of ecosystems found on Earth, including open-canopy ecosystems, which have been largely overlooked. Considering the paucity of scientific foundations promoting restoration science, policy, and practice for open tropical ecosystems, we provide overarching guidelines to restore the campo rupestre, a Neotropical, open megadiverse grassland that has been increasingly threatened by multiple human activities, especially mining. Restoration techniques for tropical grasslands are still at its infancy, and attempts to restore campo rupestre have had, so far, low to moderate success, highlighting the need for a tailored restoration framework. In a scenario of increasing degradation and scarcity of on-site restoration experiments, we propose 10 principles to improve our ability to plan, implement, and monitor restoration in campo rupestre: (1) include socioeconomic dimensions, (2) implement active restoration, (3) keep low soil fertility, (4) restore disturbance regimes, (5) address genetic structure and adaptation potential, (6) restore geographically restricted and specialized ecological interactions, (7) incorporate functional approaches, (8) use seed-based restoration strategies to enhance biodiversity, (9) translocation is inevitable, and (10) long-term monitoring is mandatory. Our principles represent the best available evidence to support better science and practice for the restoration of campo rupestre and, to some extent, can be useful for other megadiverse, fire-prone, and nutrient-poor ecosystems.

The campo rupestre is a Neotropical azonal vegetation. Its disjoint distribution and the fact that it is an old climatic buffered infertile landscape (OCBIL) have been associated with the high diversity and endemism observed in this environment. Here, we tested whether a micro-endemic species from campo rupestre shows: (1) limited zygotic gene flow; (2) lower gametic than zygotic gene flow structure; (3) substrate-driven genetic structure and (4) no evidence of Pleistocene local extinction or recolonization. By sequencing intergenic plastid regions, phenotyping inter simple sequence repeats (ISSR) and modelling present and past species suitability distributions for Vellozia auriculata we conclude that (1) zygotic gene flow is limited; (2) gametic gene flow is recurrent, but limited by elevation and distance; (3) there is no support for genetic structure driven by substrate and (4) Pleistocene climatic changes did not restrict the species to refugia, with local persistence. As long-term gene flow restrictions may lead to differentiation and speciation, our data helps to corroborate that the campo rupestre is both a cradle (due to low zygotic gene flow, prolonged isolation and consequent differentiation) and a lineage museum (due to local survival during climate oscillations). We highlight two distinct evolutionarily significant units (ESU), providing information for better conservation practice.

Global sustainability rests on a myriad of benefits provided by natural ecosystems that support human livelihoods and well-being, from biodiversity persistence to climate regulation. The undeniable importance of conserving tropical forests has drawn most of the conservation spotlight towards it. However, open ecosystems such as the Brazilian Campo Rupestre (rupestrian grassland), have been historically overlooked despite their high diversity and key associated ecosystem services. We highlight major current threats to the persistence of the Campo Rupestre emphasizing its ecological, social, cultural, geo-environmental, and economic importance. We call attention to the importance of the Campo Rupestre as a reservoir of biodiversity and ecosystem services and offer priority actions that resulted from discussions involving scientists, industry representatives, environmental managers, and other members of civil society. Proposed actions include efforts related to ecological restoration, sustainable ecotourism, protection of traditional ecological knowledge, identification of emerging research questions, and development of tailored public policies. Such issues are integrated into a framework that collectively represents a road map to safeguard the Campo Rupestre from further degradation and steer its historical overexploitation towards sustainable management. Safeguarding the future of non-forest biomes like this poses a challenge to current paradigms of nature conservation. By establishing priorities and guidelines, we propose an actionable plan, which we hope can support informed decision-making policy towards a sustainable use of the Campo Rupestre. Long Term Ecological Research PELD-CRSC-17 Conselho Nacional de Pesquisas CNPq/MCTI Fundação de Amparo à Pesquisa do Estado de São Paulo 2013/50155-0, 2010/51307-0, 2019/07773-1

South America harbors the highest plant diversity on Earth. The causes of such exceptionally high diversity remain poorly understood, despite great attention devoted to the ecology and evolution of biota in productive and geologically recent ecosystems such as the Amazon forest and the Andes. Evidence suggests ancient and extremely nutrient-poor landscapes are major centers of plant diversity and endemism, and acted as interglacial refugia, but singularities of their evolutionary history have been overlooked. Here, we examine to what extent Ocbil theory (old, climatically-buffered, infertile landscapes) may prove useful in explaining diversification patterns in some of the most diverse Neotropical ecosystems. We propose a theoretical framework that encompasses a mechanistic explanation for the predictions of Ocbil theory, and links ecological and evolutionary processes to vegetation patterns and functional traits. We review diversification patterns and population genetics in campos rupestres vegetation in light of Ocbil theory. We propose areas of future research that will accelerate and improve our understanding on the ecology and evolution of Neotropical biota on ancient, nutrient-poor vegetation. This knowledge is expected to shed light on the complex history of Neotropical plant diversification and, ultimately, provide tools for their sustainable use and conservation.

The area occupied by tropical forests in South America has continually experienced shrinkage since the Miocene, with the formation of the Dry Diagonal, which is composed of seasonally dry tropical forests and savannas (Caatinga, Cerrado, and Chaco). Here, we contribute to the understanding of the establishment of the Dry Diagonal by testing the hypotheses of “ancestral fragmentation” and of “colonization” to explain the current distribution of species in rocky humid formations of Cerrado, a Neotropical savanna in Brazil. Populations of Mandirola hirsuta (Gesneriaceae) were sampled in 25 localities; these cover the species’ entire geographical distribution, and the plastid intergenic regions psbA-trnH and trnQ-5′-rps16 were sequenced. The findings show that intrapopulation genetic variability was low, whereas interpopulation variability was high. We detected seven genetic groups that were geographically well delimited, and no signs of recent population expansion were observed. Divergence between the seven main lineages took place between the late Miocene and the Pliocene periods. In Approximate Bayesian Computation, the fragmentation scenario had a significantly higher probability than the colonization scenario. Results support the hypothesis of a former broader distribution for the humid vegetation, which was fragmented with the expansion of savannas; results also indicate population differentiation promoted by a rapid expansion of the Dry Diagonal.

 Premise of the study: Vellozia hirsuta forms a complex presenting wide morphological and anatomical variation, resulting in fi ve specifi c names and 14 morpho-anatomical patterns occurring in disjunct populations. We carried out a phylogeographical study to investigate the existence of correlation among the genetic and morphological patterns within this complex, and to determine whether it is composed of various species or should be treated as an ochlospecies, a species having widely polymorphic and weakly polytypic complex variation, with morphological characteristics varying independently.  Methods: We carried out phylogeographical analyses using cpDNA rpl32F-trnL intergenic region.  Key results: We found 20 haplotypes in 23 populations sampled. The populations are genetically structured ( Φ ST = 0.818) into four phylogeographical groups demonstrating geographical structuring but with no correlation with morpho-anatomical patterns. Our analyses do not support recognizing any of the species now synonymized under Vellozia hirsuta. The northern populations were the most genetically differentiated and could be considered a distinct taxon, as they are also morphologically different.  Conclusions: It is recommended that Vellozia hirsuta be considered a single enormously variable species. The patterns of variation within V. hirsuta probably are related to climatic changes that occurred during the Pleistocene Epoch in tropical Brazil when reductions in forest cover favored the expansion of V. hirsuta populations into extensive lowland areas. The expansion of forest cover at the end of the glaciations would have again restricted the occurrence of campos rupestres vegetation to high elevations, which constitute the current centers of diversity of this species.