João Augusto Alves Meira-Neto

Composição florística de uma floresta estacional semidecidual montana no município de Viçosa-MG

This study aims to investigate the floristic composition of the Silvicultura forest (20o45`S and 42o55´W) by comparing it to other forest compositions. Thus, the cluster analysis method of unweighted pair-group using arithmetic averages (UPGMA) was used, applying the Sorensen binary similarity index found among compared forests. A list of 154 species of 47 families was recorded. The Silvicultura forest is more similar to the montane semideciduous forests of Lavras and Atibaia, but less similar to submontane and coastal forests. These results show that temperature plays an important role in the floristic differentiation of the southern and southeastern Brazilian forest types.

Avoiding inaccuracies in tree calibration and phylogenetic community analysis using Phylocom 4.2

There is an increased interest in phylogenetic approaches for conservation biology and community analysis. Many of these analyses are carried out using the Phylocom 4.2 package. With this computational tool, already existing trees are pruned to species from community to be studied. For plant communities, a variety of megatrees including all angiosperm families are available for phylogenetic community analysis. Using the bladj algorithm, internal nodes of community trees derived from these megatrees are calibrated on time scales from fossil or molecular data provided in an ages file. The higher precision of tree calibration, the better is the ecological interpretation if we assume that the closest related species have the most superposed set of traits, the highest probability of co-occurrence in case of environmental filter effects and the highest ratio of competitive exclusion. Together with the Phylocom 4.2 package comes an ages file based on Wikstroms dating of angiosperm families (wikstrom.ages). But there are inconsistencies in syntax and/or nomenclature between internal node names of trees and the ages file from phylocom that influence the tree calibration and the subsequent analysis. To avoid that, we classified all online available megatrees according to their syntax and nomenclatureof internal nodes. For each of the four classes we provide a new, fully compatible ages file in the supplement material. Each online available megatree, pruned to the species from an example community from the Atlantic Rainforest, was calibrated twice running the bladj algorithm using once the original wikstrom.ages file and, additionally, the new ages file prepared for that tree class. Outcomes from trees calibrated by different methods have been compared. To avoid inconsistencies that push results beyond the realistic, we recommend a strict application of the four ages files provided as supplementary files.

Would protecting tropical forest fragments provide carbon and biodiversity cobenefits under REDD

Tropical forests store vast amounts of carbon and are the most biodiverse terrestrial habitats, yet they are being converted and degraded at alarming rates. Given global shortfalls in the budgets required to prevent carbon and biodiversity loss, we need to seek solutions that simultaneously address both issues. Of particular interest are carbon-based payments under the Reducing Emissions from Deforestation and Forest Degradation (REDD+) mechanism to also conserve biodiversity at no additional cost. One potential is for REDD+ to protect forest fragments, especially within biomes where contiguous forest cover has diminished dramatically, but we require empirical tests of the strength of any carbon and biodiversity cobenefits in such fragmented systems. Using the globally threatened Atlantic Forest landscape, we measured above-ground carbon stocks within forest fragments spanning 13 to 23 442 ha in area and with different degrees of isolation. We related these stocks to tree community structure and to the richness and abundance of endemic and IUCN Red-listed species. We found that increasing fragment size has a positive relationship with above-ground carbon stock and with abundance of IUCN Red-listed species and tree community structure. We also found negative relationships between distance from large forest block and tree community structure, endemic species richness and abundance, and IUCN Red-listed species abundance. These resulted in positive congruence between carbon stocks and Red-listed species, and the abundance and richness of endemic species, demonstrating vital cobenefits. As such, protecting forest fragments in hotspots of biodiversity, particularly larger fragments and those closest to sources, offers important carbon and biodiversity cobenefits. More generally, our results suggest that macroscale models of cobenefits under REDD+ have likely overlooked key benefits at small scales, indicating the necessity to apply models that include finer-grained assessments in fragmented landscapes rather than using averaged coarse-grained cells.

Influence of Soil Physical Properties on Plants of the Mussununga Ecosystem, Brazil

Distribution ranges of plant species are related to physical variables of ecosystems that limit plant growth. Therefore, each plant species response to physical factors builds up the functional diversity of an ecosystem. The higher the species richness of an ecosystem, the larger the probability of maintaining functions and the higher the potential number of plant functional groups (FGs). Thus, the richness potentially increases the number of functions of the highly diverse Atlantic Rainforest domain in Brazil. Severe plant growth limitations caused by stress, however, decrease species richness. In the Spodosols of the Mussununga, an associated ecosystem of Atlantic Rainforest, the percentage of fine sand is directly related to water retention. Moreover, the depth of the cementation layer in the Mussununga’s sandy soil is a physical factor that can affect the plants’ stress gradients. When a shallow cementation layer depth is combined with low water retention in soils and with low fine sand percentage, the double stresses of flooding in the rainy season and water scarcity in the dry season result. This study aimed to identify FGs among Mussununga plant species responding to water stress gradients of soil and to verify the effects of the gradients on plant species richness of the Mussununga. A canonical correspondence analysis (CCA) of species abundance and soil texture variables was performed on 18 plots in six physiognomies of the Mussununga. Species richness rarefactions were calculated for each vegetation form to compare diversity. The two main axes of the CCA showed two FGs responding to soil texture and cementation layer depth: stress tolerator species and mesic species. Physical variables affect plant diversity, with species richness rising as the fine sand proportion also rises in the Mussununga. The effect of the cementation layer is not significantly related to species richness variation.

Interactions, Environmental Sorting and Chance: Phylostructure of a Tropical Forest Assembly

Density dependence, environmental sorting and chance have been discussed for the purpose of understanding, predicting and explaining the species richness, composition and structural parameters of living communities. Different ecological mechanisms occur individually in an overlapping manner, so the structure of each local community is influenced by an independent mixture of these factors. To identify which of these factors prevails in organizing the species-rich tree community from 100 plots of 10 × 10 m in a primary forest patch (the Forest of Seu Nico – FSN, from the Atlantic Forest domain), we analyzed species-environment correlations via canonical correspondence analysis and identified two different pedo-environments. We analyzed the community’s phylogenetic structure using Phylocom 4.2 software to calculate the net relatedness index (NRI) and the nearest taxon index (NTI). Furthermore, we partitioned the total phylogenetic diversity into independent α and β components (ΠST). To reveal the overlap of ecological mechanisms such as neutrality, environmental filtering and density-dependent factors, we analyzed the phylogenetic structure in both pedo-environments. The species-environment correlations observed in the FSN are weak in comparison with those found in other studies, although the permanent plot presents a short environmental gradient, dividing the plot into an upper, more acidic hillside and a lower, more fertile bottom. The overall phylogenetic structure of the FSN community shows strong and significant phylogenetic overdispersion. This overdispersion indicates that density-dependent factors, such as interspecific competition, play an important role in maintaining the species richness and community structure in megadiverse ecosystems such as the FSN when we assume traits to be conserved within evolutionary lineages. The NRI and NTI are correlated positively with the soil pH and negatively with the soil’s aluminum concentration, so the bottom plots show higher phylogenetic overdispersion and lower ΠST values than the hillside plots. This pattern can be explained by the greater importance of environmental filters in more acidic soils that form less favorable habitats, while the influence of competition and therefore also the rate of competitive exclusion are higher in the more favorable, less acidic plots.

Brazil’s mining code under attack: giant mining companies impose unprecedented risk to biodiversity

Brazil owns one of the largest biodiversity in the world. It has the largest area of tropical forests, the most biodiverse tropical savanna and is one of the countries that have experienced very significant economic growth during the twentieth Century and the beginning of the twenty-first Century. It is among the top ten economies of the world, largely based on environmental resources and commodities production. Two main environmental laws from 1960’s, the Forest Code and the Mining Code, have imposed restrictions to the use of natural resources by landholders and companies up to the 2010’s. In 2012, however, big companies and political lobbies have succeeded to change the Forest Code and are threatening the sibling Mining Code.

Environmental filtering of agroforestry systems reduces the risk of biological invasion

Abstract Prevention is the most effective way of mitigating the negative impacts of exotic species invasions on biodiversity. Preventative measures include inhibiting the further dispersal and recruitment of established invasive species. We expect coffee production in agroforestry systems to reduce the recruitment of exotic species relative to monoculture stands because intercropped trees function as environmental filters that select for individuals with traits such as shade tolerance. If ecologically similar species are also closely related phylogenetically, such environmental filters should reduce phylogenetic diversity, supporting the coexistence of closely related species. Here, we test whether the taxonomic and phylogenetic diversity of native and exotic species in agroforestry systems is lower than in monocultures. We sampled the understory in 180 plots distributed in both habitats in three study sites within the Araponga municipality, Brazil, and measured understory light availability. Phylogenetic diversity was calculated as the net relatedness index (NRI) and the nearest taxon index (NTI). Understory light availability was lower in agroforestry systems. Of the 48 species found, 25 occurred in agroforestry systems, three of which were exotics. Forty-two species were found in monoculture stands (including 13 exotics). As expected, NRI and NTI indicated lower phylogenetic diversity in agroforestry systems than in monoculture stands. Agroforestry systems provide less favorable habitats for exotic species, filtering them from the understory. The mechanisms that select against exotic species remain unknown; however, shading might exclude predominantly heliophytic exotic species from the agricultural matrix. Therefore, agroforestry systems may function as buffer zones preventing invasion into sensitive ecosystems.

Structure of Brazilian Atlantic forests with occurrence of the woolly spider monkey (Brachyteles hypoxanthus)

This work examines patches of Atlantic forests in Minas Gerais State where woolly spider monkeys (Brachyteleshypoxanthus) are inhabitants in order to understand the effects of forest structure, diversity, and succession in B.hypoxanthus abundance. This study was carried out in three reserves: Rio Doce State Park (PERD), Mata do Sossego (Sossego), and Serra do Brigadeiro State Park (PESB). Structural studies were carried out by means of point-centered quarter samples in areas used by woolly spider monkeys. Evenness was lower in PERD than in the other two communities. By means of successional functional groups analysis and diametric structure, the PERD forest sample was shown to be in the later, and PESB forest sample in the earlier, stages of secondary succession. We found that tree species evenness and structural traits driven by succession were important factors in determining spider monkey abundance patterns. The PERD forest sample had lower evenness and had lower density of woolly spider monkeys than the Sossego forest sample. The lowest density of these primates was in the PESB forest sample, the earlier successional stage of secondary succession of this study.

Habitat Quality of the Woolly Spider Monkey (Brachyteles hypoxanthus)

This study examines how habitat structure affects the home range use of a group of Brachyteles hypoxanthus in the Brigadeiro State Park, Brazil. It has been reported that most of the annual feeding time of woolly spider monkeys is spent eating leaves, but they prefer fruits when available. We hypothesise that the protein-to-fibre ratio (PF; best descriptor of habitat quality for folivorous primates) is a better descriptor of habitat quality and abundance for these primates than the structural attributes of forests (basal area is the best descriptor of habitat quality for frugivorous primates of Africa and Asia). We evaluated plant community structure, successional status, and PF of leaf samples from the dominant tree populations, both within the core and from a non-core area of the home range of our study group. Forest structure was a combination of stem density and basal area of dominant tree populations. The core area had larger trees, a higher forest basal area, and higher stem density than the non-core area. Mean PF did not differ significantly between these sites, although PF was influenced by differences in tree regeneration guilds. Large-bodied monkeys could be favoured by later successional stages of forests because larger trees and denser stems prevent the need for a higher expenditure of energy for locomotion as a consequence of vertical travel when the crowns of trees are disconnected in early successional forests. Forest structure variables (such as basal area of trees) driven by succession influence woolly spider monkey abundance in a fashion similar to frugivorous monkeys of Asia and Africa, and could explain marked differences in ranging behaviour and home range use by B. hypoxanthus.

Open-Source Processing and Analysis of Aerial Imagery Acquired with a Low-Cost Unmanned Aerial System to Support Invasive Plant Management

Remote sensing by Unmanned Aerial Systems (UAS) is a dynamic evolving technology. UAS are particularly useful in environmental monitoring and management because they have the capability to provide data at high temporal and spatial resolutions. Moreover, data acquisition costs are lower than those of conventional methods such as extensive ground sampling, manned airplanes, or satellites. Small fixed-wing UAS in particular offer further potential benefits as they extend the operational coverage of the area under study at lower operator risks and accelerate data deployment times. Taking these aspects into account, UAS might be an effective tool to support management of invasive plant based on early detection and regular monitoring. A straightforward UAS approach to map invasive plant species is presented in this study with the intention of providing ready-to-use field maps essential for action-oriented management. Our UAS utilizes low-cost sensors, free-of-charge software for mission planning and an affordable, commercial aerial platform to reduce operational costs, reducing expenses with personnel while increasing overall efficiency. We illustrate our approach using a real example of invasion by Acacia mangium in a Brazilian Savanna ecosystem. A. mangium was correctly identified with an overall accuracy of 82.7% from the analysis of imagery. This approach provides land management authorities and practitioners with new prospects for environmental restoration in areas where invasive plant species are present.