Vanessa Leite Rezende

Humidity, low temperature extremes, and space influence floristic variation across an insightful gradient in the Subtropical Atlantic Forest

The use of well-sampled regions and insightful environmental gradients can provide important theoretical knowledge for understanding the drivers of tropical forest patterns and processes, which are necessary for biological conservation. We investigated the variation in tree species composition across a vegetation gradient in the Subtropical Atlantic Forest, as well as various predictors that could impact such patterns. The exploratory and confirmatory analyses included 178 sampling units distributed among 13 different forest types containing binary occurrence records for 935 species from 25,546 trees. Confirmatory analyses were conducted considering spatial autocorrelation, a well-known factor responsible for type I error inflations. The floristic heterogeneity of the study area was revealed by clear patterns of floristic differentiation between vegetation types, as well as by the significant improvements in local models (GWR—geographically weighted regressions) over global models (OLS—ordinary least squares). We found that the observed floristic variation has most likely been driven by humidity from the Atlantic Ocean, low temperature extremes and geographic distance. The latter was revealed by the high contribution of spatial components to the partial models. These results from a shrinking biological hotspot, particularly those concerning the importance of temperature extremes, represent crucial data for identifying conservation priorities, especially considering the seriousness of the temperature shifts predicted by global climate change scenarios.

Tree species composition and richness along altitudinal gradients as a tool for conservation decisions: the case of Atlantic semideciduous forest

Altitude is one of the major environmental variables influencing the distribution of tree taxa around the world, and can be a useful parameter for the development of conservation strategies. Our objectives were to obtain an overview of the conservation status of taxa from the Atlantic semideciduous seasonal forests of southeastern Brazil and check, among the floristically consistent altitudinal zones, which had the largest number of endemic, threatened and indicator species. To accomplish this, we used species occurrence and geo-climatic data from the ‘NeoTropTree’ database. First, we checked which zones were floristically consistent using an ordination method (non-metric multidimensional scaling, NMS) followed by an analysis of variance. Then, we conducted an indicator species analysis, estimated species richness, calculated the taxonomic distinctness index for all zones and evaluated important aspects for conservation, such as endemism and threat of extinction. Taxa richness, and number of endemic and threatened species decreased with increasing altitude, while the amount of indicator species for each zone increased with altitudinal elevation. These variations related to the altitudinal gradient should be considered when developing conservation strategies. We also should prioritise the conservation of the entire gradient and, whenever possible, include endemic and endangered species in forest recovery programs.

Patterns of tree composition in the southern cone of South America and its relevance to the biogeographic regionalization

The biogeographic history of southern South America has led to a markedly distinct flora within the frame of the Neotropics, which is also particularly heterogeneous in terms of its eco-geographic distribution. This environmental complexity is at the base of the many and controversial classification systems that have been proposed for the vegetation of the so-called Cono Sur region (Paraguay, Chile, Argentina, Uruguay and parts of Brazil and Bolivia). In this study, we aimed to assess the floristic consistency of the main vegetation types that inhabit the region. Our dataset consisted of 116,130 occurrence records of 3662 species of shrubs and trees in 781 sampling sites spread over six countries and eight phytogeographic domains: Atlantic Forest, Pampa, Gran Chaco, Patagonia, Southern Andean, Mediterranean Chile, Temperate Pacific, and Pacific Islands. We performed a cluster analysis and nonmetric multidimensional scaling ordination analysis of this dataset followed by multi-response permutation procedures and permutational multivariate analysis of variance and taxonomic distinction index and indicator species. The greater differentiation took place among the phytogeographic domains and leaf flush regimes (evergreen, deciduous, and semideciduous) though there was also a remarkable latitudinal gradient. Our analyses showed that the pre-defined vegetation types were consistent in terms of woody flora composition and have a considerable number of indicators, many of which endemic. In terms of conservation prioritization, Atlantic Rain Forest therefore has importance because of its high species richness while temperate and mediterranean forests west of the Andes should not be ignored given that they show much higher endemism than would be expected given their species richness.

Floristic distributional patterns in a diverse ecotonal area in South America

The Paraguayan territory and region, in the centre of South America, is a huge transition area with a succession of various vegetation types. However, this area has received little attention from researchers, with few works published on its flora and its delimitations. We aimed to identify the most important environmental driving forces and delimit floristic patterns in this region, since understanding the forces that drive floristic variations in this ecotonal region could help comprehend the distribution of vegetation not only in this region but throughout South America. We obtained 1234 tree species occurrence records, 205 geographic coordinates and 23 environmental variables and altitude from the ‘NeoTropTree’ database and verified the influence and contribution of environmental factors through variance partition. We tested the floristic consistency of the different vegetation types using dendrogram, indicator species and ordination analyses. We also constructed multiple linear models to check the correlation between species distribution and environmental variables. We found eight consistent vegetation types. The spatial variables coupled with environmental variables were more important than individual environmental or spatial variables. Among the environmental variables, the aridity index was the most important. Despite the importance of spatial factors, due to environmental heterogeneity, we found a gradient related to climate and edaphic variables related to tree flora. The results confirm that the Paraguayan territory and region can be considered to be a diversified and important ecotone area in South America with respect to tree flora.

Trilhas e seu papel ecológico: o que temos aprendido e quais as perspectivas para a restauração de ecossistemas?

Nosso objetivo foi revisar o papel ecologico das trilhas e inserir essa tematica nos projetos de restauracao ecologica. Para uma compreensao abrangente desse papel ecologico, abordamos tanto as possiveis aplicacoes das trilhas para projetos de Educacao Ambiental (EA) quanto seus impactos sobre a vegetacao. Mostramos que as trilhas ecologicas constituem espacos adequados para a pratica de programas de EA. Por outro lado, apontamos uma serie de potenciais problemas advindos da abertura e utilizacao de trilhas, como, por exemplo, compactacao do solo e alteracoes na composicao, estrutura e diversidade da vegetacao adjacente, para entao indicarmos que e possivel abordar as trilhas nos projetos de restauracao de ecossistemas. Concluimos sugerindo algumas perguntas que poderao nortear os futuros trabalhos sobre trilhas e vegetacao, incluindo suas conexoes com a restauracao ecologica.

A MINERAÇÃO EM MINAS GERAIS: UMA ANÁLISE DE SUA EXPANSÃO E OS IMPACTOS AMBIENTAIS E SOCIAIS CAUSADOS POR DÉCADAS DE EXPLORAÇÃO

The state of Minas Gerais has been suffering from the mineral exploration since inception of colonization in Brazil. Despite this, today is the state that has more mineral reserves, which creates an encounter between mineral production and environmental conservation, since the mineral extraction generates deforestation and other environmental impacts. The aim of this study was to obtain an overview of the expansion of mining and the resulting impacts of mining over the years in the state. The results showed that in recent decades there has been a large increase in the expansion of mines in the state, as well as environmental and public health impacts in cities that harbor the oldest mining. Thus, it was concluded that to be an important source of savings for Brazil, it becomes necessary to review the environmental policy of large mining and increase supervision by the public agency so that we can ensure the sources of mineral and quality environmental for future generations.