Fragmented Brazilian Atlantic Forest Research Articles

Genetic Structure and Diversity of Dalbergia nigra from Brazilian Atlantic Forest Fragments

Dalbergia nigra is a long-living tree endemic to the Atlantic Rain Forest. Due to its high commercial value, this species has been widely exploited for timber production and is now endangered. It is widely known that understanding patterns of genetic structure is paramount for conserving threatened species. We analyzed the genetic diversity of 140 individuals from four different forest fragments in the southern region of Bahia, Brazil, to verify the possible effects of fragmentation on these populations and provide information for conservation initiatives. High polymorphism levels were detected from the genotyping of nine microsatellite loci (mean HE = 0.733). All populations showed high genetic diversity; however, a reduction of genetic diversity was detected in each population (HO < HE). The average fixation index was high and significant (f = 0.167), which could be due to the occurrence of inbreeding, the Wahlund effect, reproductive system, or from null alleles. Genetic differentiation among populations was high (mean θP = 0.118), suggesting strong isolation, a pattern consistent with historically low gene flow. The Bayesian analysis revealed five different genetic groups, among which three groups correspond to three different forest fragments, and two groups showed the genetic subdivision of individuals from the other forest fragment. Based on our results, the suggested conservation strategy for D. nigra populations in the southern region of Bahia, Brazil, involves high environmental investments to protect all sampled forest fragments and individuals. Another strategy would be to collect seeds from all individuals from the sampled fragments and start a new population with human interference in its evolutive history inside a protection unit.

Potential aboveground biomass increase in Brazilian Atlantic Forest fragments with climate change.

Fragmented tropical forest landscapes preserve much of the remaining biodiversity and carbon stocks. Climate change is expected to intensify droughts and increase fire hazard and fire intensities, thereby causing habitat deterioration, and losses of biodiversity and carbon stock losses. Understanding the trajectories that these landscapes may follow under increased climate pressure is imperative for establishing strategies for conservation of biodiversity and ecosystem services. Here, we used a quantitative predictive modelling approach to project the spatial distribution of the aboveground biomass density (AGB) by the end of the 21st century across the Brazilian Atlantic Forest (AF) domain. To develop the models, we used the maximum entropy method with projected climate data to 2100, based on the Intergovernmental Panel on Climate Change Representative Concentration Pathway (RCP) 4.5 from the fifth Assessment Report. Our AGB models had a satisfactory performance (area under the curve > 0.75 and p value < .05). The models projected a significant increase of 8.5% in the total carbon stock. Overall, the projections indicated that 76.9% of the AF domain would have suitable climatic conditions for increasing biomass by 2100 considering the RCP 4.5 scenario, in the absence of deforestation. Of the existing forest fragments, 34.7% are projected to increase their AGB, while 2.6% are projected to have their AGB reduced by 2100. The regions likely to lose most AGB-up to 40% compared to the baseline-are found between latitudes 13° and 20° south. Overall, although climate change effects on AGB vary latitudinally for the 2071-2100 period under the RCP 4.5 scenario, our model indicates that AGB stocks can potentially increase across a large fraction of the AF. The patterns found here are recommended to be taken into consideration during the planning of restoration efforts, as part of climate change mitigation strategies in the AF and elsewhere in Brazil.

Selective logging that occurred decades ago is still impacting aboveground biomass and tree assemblage structure in Brazilian semi-deciduous seasonal Atlantic forest fragments

The majority of tropical forests in the world have undergone or are still undergoing selective logging. This human disturbance is among the actions that most affect the dynamics of the carbon stocks of tropical forests and also the vegetation structure, richness, and species composition. One of the most widely used approaches to understand forest responses to this disturbance has been to compare them with other undisturbed forests in the given region. Here, we measure the effects of the selective logging history on the aboveground biomass, tree abundance, basal area, and wood density in four Brazilian Atlantic Forest fragments logged once, 35–45 years before the current sampling. We used two unlogged forest fragments as reference ecosystems. We found 40% less aboveground biomass (AGB) and 31% lower basal area in logged than in unlogged forest fragments. Large trees (trees with a diameter greater than 50 cm) were strongly affected by selective logging, showing AGB, basal area, mean wood density and tree abundance values 59%, 52%, and 46%, respectively, lower in logged forest fragments. We found an increase in the abundance of softwood, early-successional species in logged forests, where 45% of the AGB accumulated was due to only two species (Astronium graveolens Jacq and Gallesia integrifolia (Spreng.) Harms). The opposite was observed in unlogged forest fragments, where two late successional hardwood species (Aspidosperma polyneuron Müll.Arg and Holocalyx balansae Micheli) accumulated 38% of the AGB. Our findings indicate that even decades after the last logging event semi-deciduous seasonal Atlantic Forest fragments with a selective logging history may present different AGB, structure, and functional composition from the expected pattern for old-growth forests in the given region.

Living in the sunlight: micro-environments with higher exposure of sunlight have more abundance and diversity of Hymenoptera in a Brazilian Atlantic Forest fragment

Living in the sunlight: micro-environments with higher exposure of sunlight have more abundance and diversity of Hymenoptera in a Brazilian Atlantic Forest fragment

Marked systemic necrotizing disease in a Leptodactylus vastus (Anura: Leptodactylidae) from an urban reserve in northeastern Brazil

The decline of amphibian populations concerns scientists worldwide and has been related to the spreading infectious diseases, among other environmental factors. Acute mass mortality with hemorrhagic and necrotic lesions has been described and associated with wild amphibian viruses. These diseases were first recorded in Central America and Australia in the early 1990s and later in Brazilian Atlantic Forest fragments. Epizootiological data on these infections must be included in other Brazilian phytogeographic regions and domains. This work aimed to report a systemic necrotic morbid state in a native Leptodactylus vastus from an urban reserve in northeastern Brazil, describing clinical and pathological findings and discussing its importance and likely etiologies. An adult L. vastus presented an erythematous oral cavity with multifocal point-like erosions, sublingual congested vessels, oropharyngeal edema, and mild esophageal mucosal prolapse. After therapeutic protocol, the patient showed no improvement; then, he was humanely euthanized. Necropsy demonstrated moderate to marked multicentric chronic necrotizing lesions. Histopathology revealed diffuse necrotic tissues with a few intracytoplasmic amphophilic inclusions in cellular remnants, with minor hemoparasites, helminths, and bacterial granulomatous coinfections. Clinical and pathological findings suggested a major chronic viral infection with minor coinfections. In the current case, confirmation of etiology struggled with financial and logistic limitations. Future partnerships will enable definitive diagnostics. This is the first record of systemic necrotizing disease in a wild frog in Ceará state, northeastern Brazil, and it is a red flag to emerging infectious diseases surveillance in this geographic area.

Six new species of Cladosporium associated with decayed leaves of native bamboo (Bambusoideae) in a fragment of Brazilian Atlantic Forest

The Atlantic Forest has the greatest diversity of plants per hectare, and it is considered the main center of bamboo biodiversity in the world. Studies on bambusicolous fungi are scarce and concentrated in temperate regions. Cladosporium is one of the largest genera of dematiaceous hyphomycetes fungus and their adaptation to different environments allows them to have a broad lifestyle. Currently, this genus has been taxonomically and phylogenetically elucidating with the help of extensive polyphasic analyzes. This study aimed to characterize 17 Cladosporium isolates associated with decayed leaves of three bamboo species at a fragment of the Brazilian Atlantic Forest, namely “Parque Estadual da Serra do Brigadeiro”, Minas Gerais state, Brazil. Phylogenetic studies revealed that all isolates belong to the C. cladosporioides species complex. Six new Cladosporium species were found and named herein as C. aulonemiae, C. bambusicola, C. benschii, C. brigadeirensis, C. chusqueae and C. pseudotenuissimum. This study contributes with several taxonomic novelties for knowledge about the diversity of the C. cladosporioides species complex.

Selective Logging that Occurred Decades Ago is Still Impacting Aboveground Biomass and Tree Assemblage Structure in Brazilian Semi-Deciduous Seasonal Atlantic Forest Fragments

Selective Logging that Occurred Decades Ago is Still Impacting Aboveground Biomass and Tree Assemblage Structure in Brazilian Semi-Deciduous Seasonal Atlantic Forest Fragments

A High Resolution Image Based Approach for Estimating the Canopy Cover of a Semi-Deciduous Brazilian Atlantic Forest Fragment

The Atlantic Forest in Brazil has been suffering natural and anthropic perturbations over the years, which has been impacting, qualitatively and quantitatively, with different degrees and intensities, its canopy cover. These perturbations can be caused by the selective cut of species, burning, natural death of trees, among several other factors, which act directly on the composition and the floristic diversity of fragments of the forest. The main motivation for conducting this work was to alert about the relevance of the Atlantic forest conservation and the need for a constant monitoring system to preserve what has been left of it. This can be partially achieved by permanently estimating its canopy cover. This paper describes the implementation and evaluation of the descriptors: energy, entropy, homogeneity, contrast and the sum of the high-frequency Discrete Fourier Transform (DFT), for estimating canopy cover based on High Resolution Camera (HRC) satellite images. The analyses carried out based on the results of the experiments showed that the energy descriptor was the best descriptor among those used and, comparatively to the others, obtained the higher correlation (r), determination (R) and significance (p). Based on the experiments, the energy descriptor presented an expressive potential to be used in processes for estimating the canopy cover based on satellite images, in large areas of the semi-deciduous forest.

Geography, Host Genetics, and Cross-Domain Microbial Networks Structure the Skin Microbiota of Fragmented Brazilian Atlantic Forest Frog Populations.

The host‐associated microbiome plays a significant role in health. However, the roles of factors such as host genetics and microbial interactions in determining microbiome diversity remain unclear. We examined these factors using amplicon‐based sequencing of 175 Thoropa taophora frog skin swabs collected from a naturally fragmented landscape in southeastern Brazil. Specifically, we examined (1) the effects of geography and host genetics on microbiome diversity and structure; (2) the structure of microbial eukaryotic and bacterial co‐occurrence networks; and (3) co‐occurrence between microeukaryotes with bacterial OTUs known to affect growth of the fungal pathogen Batrachochytrium dendrobatidis (Bd). While bacterial alpha diversity varied by both site type and host MHC IIB genotype, microeukaryotic alpha diversity varied only by site type. However, bacteria and microeukaryote composition showed variation according to both site type and host MHC IIB genotype. Our network analysis showed the highest connectivity when both eukaryotes and bacteria were included, implying that ecological interactions may occur among domains. Lastly, anti‐Bd bacteria were not broadly negatively co‐associated with the fungal microbiome and were positively associated with potential amphibian parasites. Our findings emphasize the importance of considering both domains in microbiome research and suggest that for effective probiotic strategies for amphibian disease management, considering potential interactions among all members of the microbiome is crucial.

Assessment of genetic diversity and population structure of Eulaema nigrita (Hymenoptera: Apidae: Euglossini) as a factor of habitat type in Brazilian Atlantic forest fragments

AbstractIn many organisms, habitat affects ecological and genetic diversity and, for certain species, it is expected that a large population should have higher genetic diversity than a smaller population. We analysed the genetics of males of the orchid bee, Eulaema nigrita (Hymenoptera: Apidae) and examined the links between local abundance and habitat with genetic diversity. We also investigated the impact of landscape features on genetic population structure, through microsatellite and mitochondrial DNA analysis, among populations found across 700 km of Brazilian Atlantic forest fragments. We found that genetic variation was not a function of local abundance, but it correlated significantly with habitat. There was significant but low genetic differentiation among populations. We found a single mitochondrial DNA haplotype in all sequenced specimens, which may be widespread throughout the Atlantic forest. Our results reinforce the idea that orchid bees can fly long distances. High-dispersal capacity, together with insufficient time in eventual isolation, can directly contribute to the high degree of similarity among populations for this species, despite their wide geographical distribution.

The dear enemy effect drives conspecific aggressiveness in an Azteca-Cecropia system

Territoriality is costly, and the accurate identification of intruders and the decision to perform aggressive responses are key behavioral traits in social animals. We studied aggression among individuals belonging to close and distant nests of the plant-ant Azteca muelleri, which lives in stems of the pioneer tree Cecropia glaziovii. More specifically, we aim to investigate if the DE (dear-enemy effect—less aggression towards neighbors than strangers) or NN (nasty-neighbor effect—less aggression to strangers than neighbors) effects or even none of them apply for this iconic Azteca-Cecropia system. We further checked if ant aggression towards conspecifics is related to cuticular hydrocarbon profiles (CHCs), which provide chemical cues for nestmate recognition. Therefore, we sampled 46 nests of A. muelleri in three Brazilian Atlantic forest fragments and performed behavioral trials within and between sites. Consistently with the DE effect, we found higher aggression levels in ‘between sites’ versus ‘within sites’ treatments as well as a positive effect of spatial distance on ant aggressiveness. We found no effect of the overall dissimilarities on CHC blend on ant aggressiveness, but of one CHC class, the methylated alkanes. Overall, we provide key insights on nest-mate recognition in obligatory ant-plant mutualisms.

First description of a tent used by Platyrrhinus recifinus

AbstractSome species of Neotropical bats of the family Phyllostomidae (leaf‐nosed bats) modify the leaves of plants to construct ‘tents’ for daytime roosts. However, little is known about which bat species are associated with this behaviour. Here, I present the first description of the use of two tents by Recife Broad‐nosed Bat, Platyrrhinus recifinus, constructed in leaves of Miconia brunnea in a degraded Brazilian Atlantic forest fragment. Both structures had the architectural style of tents‐boat/apical. The shape of the leaves may mediate the architecture of these tents. In addition, they observed that only one male attended the two tents during the same night. This description provides new insights into the biology and behaviour of Platyrrhinus species. I further highlight several unknown for most tent‐making bats that merit future research.

Pre-capture monitoring for a planned translocation of a northern muriqui (&lt;i&gt;Brachyteles hypoxanthus&lt;/i&gt;) female from a forest fragment surrounding Caparaó National Park, Brazil

&#x0D; &#x0D; &#x0D; Conservation translocation may play an important and necessary role in primate conservation as several species are facing an impending extinction risk and population decline. However, translocations are a high-cost endeavor. Therefore, pre-capturing monitoring can be an essential component in the success of primate translocation. In this study, we report the first confirmed sighting of a female Northern Muriqui (Brachyteles hypoxanthus) stranded alone in a small fragment of Brazilian Atlantic Forest, and her pre-capture monitoring for a future planned translocation. Monitoring was realized from June 2018 to July 2019, and included data collection through direct observational and arboreal camera trap methods, and non-invasive collection of faecal samples for additional genetic studies. Our results showed that the female used the total area of the 1-ha forest fragment with an average daily displacement of 59.6 m ± 76.2. The female spent most of the time ‘Resting’, followed by ‘Travelling’ and ‘Feeding’, which did not vary significantly between seasons. Intraspecific activity pattern variations may be related to the amount and quality of the feeding resources available in the forest fragments. No stereotyped behavior or advertising signals were reported during the monitoring. Our study provides insights on solitary primates living in marginal habitats and highlight the importance of pre-capture monitoring to provide important information on the general behavior of the target individuals, on the regular movements and overall home ranges, and to help to guide future translocations.&#x0D; &#x0D; &#x0D;

Influence of the edge-core gradient on the scorpion assemblage (Arachnida, Scorpiones) in a Brazilian Atlantic forest

Habitat structure plays a major role in the distribution of species in a given area. Edge-core gradients may be useful for examining the effects of habitat modifications, as they represent changes in habitat structure at a small spatial scale. Here, we analyzed how scorpion assemblages were affected by variations in habitat structure along an edge-core gradient in a Brazilian Atlantic forest fragment. Scorpions were collected during 20 months (May 2007 – December 2008) in 112 pitfall traps, arranged from the fragment edge to 500 m inside the forest interior. All pitfall traps were checked in each two days with all scorpions found being collected. We also measured eight environmental variables along the edge-core gradient: canopy cover, leaf litter depth, diameter at breast height (DBH), plus the densities of fallen logs, stones, trees, shrubs, and bromeliads. We collected a total of 767 scorpions, all within the Buthidae family, and five species were identified (Ananteris mauryi, Tityus brazilae, T. neglectus, T. pusillus, and T. stigmurus). The abundance of these arachnids was positively influenced by habitat structure, with more individuals occurring in areas with trees having higher DBH values. However, species richness and composition were not affected by any of the environmental variables. Our results suggest that, at small spatial scales, scorpion assemblage (i.e. abundance) is sensitive to changes in habitat structure. Here, we have highlighted the importance of habitat structure for the maintenance of scorpion assemblages in their habitats.

Occurrence of Ants (Hymenoptera: Formicidae) in both Leaf Litter and Twigs in Atlantic Forest

Twigs in the litter derived from the fragmentation of tree branches form one microhabitat, where entire colonies of ants, both leaf litter and arboreal species, can be found. The objective was to survey ant species that are presente in both the leaf litter and twigs simultaneously. We describe the nest type, the social structure of the colonies and the trophic guild membership of these species. Samples were collected from 10 preserved fragments of Brazilian Atlantic forest. We used Berlese funnels to collect leaf litter ants and manual collection for twig ants. We recorded 80 ant species; 60 species were in leaf litter samples and 35 species were in twigs. Of the total species, only 15 (20%) occurred simultaneously in the leaf litter and in twigs. Of these species, Gnamptogenys striatula, Pheidole sarcina, P. sospes and Solenopsis sp. 2 were the most frequent among leaf litter dwellers, and Myrmelachista catharinae was the most common arboreal species. Most of these belonged to generalista and predator guilds, with “polydomous nests” and colonies monogynous.

IS BIOTIC INTEGRITY OF URBAN FORESTS REMANTS RELATED WITH THEIR SIZE AND SHAPE?

ABSTRACT The Brazilian Atlantic Forest (BAF) is one of the biodiversity hotspots, but in the last decades, it has been fragmented due to agricultural and urban-industrial expansion, which has a strong impact on forest fragments. The goal of this study was to analyze the Biotic Integrity Index (BII) in fragments of BAF in two medium-sized cities in Southeastern Brazil and to analyze the relation between BII and landscape metrics (size and shape). The method (BII) has eleven indicators (litter, grass, dead trees, exotic species, vines, gaps, epiphytes, orchids, palms, later species in canopy and understory). The survey was carried out in nine forest fragments in Ribeirao Preto (SP) and 23 in Sorocaba (SP), with a size variation between 0.33 and 185 ha, all of them in urban influence. The relation between BII and landscape metrics were analyzed by the Pearson regression. BII value was registered from 28.7 to 40.0 to Ribeirao Preto and from 22.34 to 35.34 to Sorocaba. Pearson regression was strong between IBB and the size for both cities (p= 0.742 to Ribeirao Preto, and p= 0.679 to Sorocaba). Pearson regression between IBB and shape was medium to Ribeirao Preto (p= 0.47) and weak to Sorocaba (0.1838). The results showed that there is a strong relation between BII and size, and less correlation between BII and shape. However, only size is not able to explain all variation in integrity, suggesting that other factors such as disturbance history and conservation management should have greater influence than the fragment size.

Cohabitation and niche overlap in the occupation of twigs by arthropods in the leaf litter of Brazilian Atlantic Forest

In tropical forests, twigs are the nesting resources most frequently occupied by ants in the leaf litter. During occupation, this resource may be shared among different arthropods, such as ants or non-ant arthropods, but the mechanisms that promote cohabitation in this context are poorly known. In this study, we examined if twig structure influences species cohabitation. Additionally, we calculated co-occurrence and niche overlap metrics for ant species and non-ant arthropods occupying the same twigs in the leaf litter. We collected 52 species of ants and 82 morphospecies of non-ant arthropods inside 575 twigs from fragments of Brazilian Atlantic Forest. Thirty-six ant species cohabited with non-ant arthropods, which were primarily Isopoda and Coleoptera. We observed that the twigs most commonly shared by ants and non-ant arthropods were wider, longer, and had a larger number of holes. We also found that cohabiting ants and non-ant arthropods had higher co-occurrence and niche overlap scores. We suggest that twig diameter is an important factor determining occupation by ants and other arthropods. When the twig is occupied by more than one ant species, our results show that niche overlap and cohabitation with non-ant arthropods are less common. We conclude that examining twig structure is important to better understand arthropod species cohabitation in leaf litter twigs and to study coexistence in ant assemblages that use twigs.

Bryophyte community diversity and structure associated with Asplenium auritum fern (Aspleniaceae) in a Brazilian Atlantic forest fragment

Introduction: Local environmental filters have shown the influence on the bryophyte diversity and structure communities, but there are limited studies that analyze how biotic relationships filters influence these communities. Objective: To evaluate whether the influence of fern Asplenium auritum cover determine changes in species richness and composition of bryophyte communities, in a semideciduous remnant forest, Minas Gerais, Brazil. Methods: We selected one transect of 300 m in each of six areas where Asplenium auritum was present. In all transect we estimated plant cover in 39 10 × 10 cm plots randomly distributed. We compare the estimated species richness and composition of bryophyte between fern coverage levels. Results: We found 60 species in 35 genera and 23 families. Weft and mat were the most represented life-forms. Fern cover had no significant effect on bryophyte species richness and composition. Conclusions: Bryophyte cover appears to improve fern development and promote the coexistence of several bryophyte species. Bryophyte cover probably predicts variations in species richness and drives the species assemblage in this community.

Fine-scale topography shape richness, community composition, stem and biomass hyperdominant species in Brazilian Atlantic forest

Topography is an important driver that determines diversity patterns and ecosystem functioning in tropical forests. However, there are few studies analyzing contrasting topographical conditions on the relative importance of species to ecosystem functioning, mainly on those who have a greater contribution (i.e., hyperdominant species). We aimed to evaluate whether contrasting topographical conditions determine changes in tree species richness, community composition, and the number of stem and biomass hyperdominant species in a Brazilian Atlantic remnant forest fragment. We selected two areas on distinct hillsides with contrasting topographic conditions, at the biological reserve of the Federal University of Viçosa, Minas Gerais state, southeastern Brazil. Each area (100 × 100 m) was sub-divided into 100 plots of 10 × 10 m. From each plot, all trees having diameter at breast height (DBH) ≥ 10 cm were identified to the species level and tagged for measurement. We measured three topographic variables (slope, elevation, and convexity) in each plot, based on the assumption that these variables may affect tree species diversity, species composition, and ecosystem function (aboveground biomass). The AGB of individual stems was calculated in all plots. We performed a multivariate regression tree for estimating topographical heterogeneity in each area. We found that species richness differed significantly between areas. Species richness in the Northeast area (the more topographically heterogeneous one) was 48% higher than that in the Southeast area, which is less topographically heterogeneous. The tree species composition varied considerably between areas, with similar AGB patterns being registered among plots. The number of stem hyperdominants varied significantly between areas. In the Southeast area, only two species out of the 85 recorded (2.38%) accounted for 50% of the number of stems hyperdominants, while in the Northeast area 10 species (7.94%) accounted for 50% of stems hyperdominants. Our results showed that high topographic heterogeneity induces high species richness and that the number of stem and biomass hyperdominant species increase along with richness on a local scale. Based on our results, we presume that biomass hyperdominance can also strongly influence forest ecosystem functioning on a local scale.

Cross-taxon congruence in insect responses to fragmentation of Brazilian Atlantic forest

Anthropogenic disturbance causes many impacts across multiple levels of biological organization from populations to ecosystems. However, the extent of cross-taxon congruence in biotic responses to disturbance, and therefore the utility of using particular taxa as indicators of broader biotic responses, is poorly known. In this study, we examine the extent to which variation in alpha diversity, beta diversity and species composition of ants, fruit-feeding butterflies, dung beetles and termites in relation to fragment size are congruent in the highly fragmented Brazilian Atlantic forest. Our results show generally low and inconsistent congruence, typically occurring for particular pairs of taxa only (such as butterflies and dung beetles for species composition, and ants and termites for Hill diversity-1D) or not at all (such as for species richness). In synthesis, there some universal community-level attributes and taxa (i.e., attributes responding consistently and congruently across taxa) have been proved to be sensitive in general. Vegetation structure and spatial location of fragments were not significant predictors of ant and termite species composition, but explained 21% and 40% of the variation in species composition of dung beetles and butterflies, respectively. In addition, we found no general increase in the ratio of generalists to specialists with decreasing fragment size. The overall lack of cross-taxon congruence means that a single taxon cannot provide a reliable indication of biotic responses to fragmentation in our study system. This can be explained by taxon-specific responses to variation in tree diversity, tree functional attributes and the spatial location of fragments. Our study therefore provides support for a multi-taxon approach to biodiversity monitoring and conservation planning.