Atlantic Forest Fragments Research Articles

Does the presence of Ethanol and Flunitrazepam (Rohypnol®) influence the attractiveness of scavenger insects to carcasses? A pilot study in an Atlantic Forest fragment

Does the presence of Ethanol and Flunitrazepam (Rohypnol®) influence the attractiveness of scavenger insects to carcasses? A pilot study in an Atlantic Forest fragment

Vertical Stratification of Butterfly Assemblages Persists in Highly Disturbed Forest Fragments of the Brazilian Atlantic Forest

Vertical stratification is a property of forest habitats related to the differential distribution of organisms according to the variation in the conditions, from the understory to the canopy. Here, we aimed to test whether butterfly assemblages from highly disturbed forests maintain the pattern of vertical stratification. We hypothesized that degraded forests would not exhibit vertical stratification due to the low variation in the microhabitat conditions along the vertical gradient, resulting from the canopy openness. To test this, we sampled fruit-feeding butterflies with bait traps, alternately disposed between the understory and canopy of three secondary forest fragments in a very fragmented Atlantic Forest landscape, for one year. We found that the vertical strata differed in terms of species composition, with a high contribution by the nestedness component on the beta diversity spatial variation. The understory assemblages had a higher abundance and were more diverse than the upper stratum. We demonstrated that vertical stratification is maintained even in disturbed forests; however, this does not necessarily provide support for a good quality and functioning ecosystem in these habitats. The butterfly assemblages recorded here are a subset of the species pool that inhabits conserved remnants. Thus, even being represented by species commonly found in disturbed habitats, the dynamic of vertical stratification of assemblages remains.

Linking changes in landscape structure to insect herbivory in forest edges and interiors of Atlantic Forest remnants.

Human activities have triggered profound changes in natural landscapes, resulting in species loss and disruption of pivotal ecological interactions such as insect herbivory. This antagonistic interaction is affected by complex pathways (e.g., abundance of herbivores and predators, plant chemical defenses, and resource availability), but the knowledge regarding how forest loss and fragmentation affect insect herbivory in human-modified tropical landscapes still remains poorly understood. In this context, we assessed multi-pathways by which changes in landscape structure likely influence insect herbivory in 20 Atlantic forest fragments in Brazil. Using path analysis, we estimated the direct effects of forest cover and forest edge density, and the indirect effect via canopy openness, number of understory plants and phenolic compounds, on leaf damage in understory plants located in the edge and interior of forest fragments. In particular, plants located in forest edges experienced greater leaf damage than interior ones. We observed that landscape edge density exerted a positive and direct effect on leaf damage in plants sampled at the edge of forest fragments. Our findings also indicated that forest loss and increase of edge density led to an increase in the canopy opening in the forest interior, which causes a reduction in the number of understory plants and, consequently, an increase in leaf damage. In addition, we detected that phenolic compounds negatively influence leaf damage in forest interior plants. Given the increasing forest loss in tropical regions, in which forest fragments become stranded in highly deforested, edge-dominated and degraded landscapes, our study highlights the pervasive enhancement in insect herbivory in remaining forest fragments-especially along forest edges and canopy gaps in the forest interior. As a result, increased herbivory is likely to affect forest regeneration and accelerate the ecological meltdown processes in these highly deforested and disturbed anthropogenic landscapes.

Bird richness at Sítio do Sol in Cabreúva, State of São Paulo, Brazil

The Atlantic Forest biome has suffered great devastation but still possesses a vast biological and endemic richness, making its preservation essential. The Atlantic Forest fragments located in the interior of the state of São Paulo have not been studied as much as other areas, mainly in the municipality of Cabreúva. Therefore, this study aimed to characterize the bird richness of the Sítio do Sol property, in Cabreúva, São Paulo. The study was carried out from August 2021 to September 2022, covering seasonality. The findings revealed that 193 species were registered, distributed among 52 families, and 23 orders, with a predominance of the Passeriformes order and the Tyrannidae family. The most observed trophic guild among species was insectivorous, accounting for 78 (41%) species, followed by omnivorous with 59 (31%) species, carnivorous 18 (9%), frugivorous 16 (8%), granivorous 12 (6%), nectarivorous 8 (4%), and detritivorous species 2 (1%), with lower richness. This study is one of the few bird surveys carried out in the municipality of Cabreúva and indicates that even in small forest fragments, there is a considerable species richness. Developing more fauna surveys and management plans for the species present in the area is important to preserve these birds.

Long-Term Trends in Mosquito Vector Populations and Their Impact on Yellow Fever Outbreaks in Atlantic Forest Fragments of Rio De Janeiro, Brazil (2016-2021).

Among all living beings, mosquitoes account for the highest number of human fatalities. Our study aimed to determine mosquito egg abundance fluctuation from 2015 to 2020, in order to observe which years had the highest mosquito vector densities and whether they coincided with yellow fever virus outbreaks in both human and nonhuman primates. The study area included Atlantic Forest fragments in the state of Rio de Janeiro. Studies from the Diptera Laboratory at FIOCRUZ were selected and compared along a timeline period of the field collections. The highest peak in egg abundance from the analyzed studies was observed from 2016 to 2017 and from 2015 to 2016. The lowest egg abundance was during the collection periods from 2018 to 2019 and 2019 to 2020. The species with the highest abundance throughout all the periods of the studies analyzed was Haemagogus leucocelaenus, representing 87% of all epidemiological species identified. The species with the lowest abundance was Hg. Janthinomys, representing only 1%. Monitoring the population of mosquitoes is imperative for disease surveillance, as the rise in specimens of various vector species directly impacts the occurrence of yellow fever cases in both nonhuman primates and human populations.

Biologia de nidificação de Euglossa cordata (Apidae: Euglossini) em áreas abertas no Extremo Sul Baiano

The genus Euglossa comprises a group of approximately 110 cataloged bee species found throughout the Neotropical region. Among these species, Euglossa cordata (Linnaeus, 1758) has a wide distribution in different environments. This research aimed to analyze aspects of the nesting biology of E. cordata in open areas near Atlantic Forest fragments in the Extreme South of Bahia, Brazil. Collections were carried out using PET bottle traps, a methodology commonly employed for capturing Meliponini but adapted for the first time in this study, presenting a low cost and good applicability for studies on Euglossa bees. Ten traps were randomly distributed in open environments at the Federal Institute of Bahia. Three nests of E. cordata were found, with a total of thirteen brood cells and six female emergences in traps 2 and 3. In all nests, the cells were constructed in a circular manner and arranged close to each other. The cells were built with resin and had a scalene trapezoid shape with variations in diameter and length. Studies on bees of the Euglossini tribe, popularly known as orchid bees, often focus on males collected using odor baits. Conversely, studies on females and nesting biology are scarce. Thus, methodologies that facilitate the capture of females and Euglossini nests are extremely relevant for enhancing our understanding of the group.

Influence of the leaf-cutting ant Atta sexdens Linnaeus (1758) on the taxonomic and functional diversity of woody plants in Atlantic Forest fragments

Influence of the leaf-cutting ant Atta sexdens Linnaeus (1758) on the taxonomic and functional diversity of woody plants in Atlantic Forest fragments

Post‐drought community turnover and functional redundancy in a tropical forest understorey

AbstractQuestionsDrought events are increasingly frequent, threatening the biodiversity of tropical forests. The understorey comprises a large fraction of the total plant species richness of these systems with the presence of highly diverse angiosperm families. Here, we quantified the effects of a drought on abundance and functional structures and on the ecosystem functioning of Rubiaceae assemblages along a topographic gradient.LocationMata das Flores State Park, an Atlantic Forest fragment in southeast Brazil.MethodsTwo vegetation surveys were performed: one during an El Niño‐induced drought, and the other three years after this drought. Abundance and functional structures were assessed using the 16 most‐abundant species of Rubiaceae, which comprised 92% of the total abundance. A litter decomposition experiment was carried out to estimate the percentage of mass loss by the Rubiaceae species. We carried out Procrustes analyses on abundance and functional structures and used Generalized Linear Mixed Models to test the effects of drought and topographic habitats on taxonomic and functional compositions, and mass loss.ResultsWe found that the functional structure and mass loss remained constant despite significant changes in the abundance structure after the drought.ConclusionThe evidence points to the maintenance of ecosystem functioning through functional redundancy, because functionally similar less‐abundant species replaced each other after the drought. We show that swarms of species can maintain biological diversity and stability in ecosystem functioning under drought in the understorey of a tropical forest.

Diversity and Flight Patterns of Caddisflies (Trichoptera) in an Atlantic Forest Fragment: Implications for Species Conservation in Threatened Ecosystems.

Anthropogenic activities have decimated the Atlantic Forest domain (AF) and increased the pressure on freshwater biota, such as Trichoptera, which is the most affected order by the current insect decline. Adult mobility is crucial for the colonisation of new environments unconnected by water sources. In this article, we describe the assemblage of caddisflies in a preserved AF fragment related to their functional feeding group and provide empirical data on the patterns of horizontal and vertical flight. Adults were collected using white sheet and light attraction traps, placed at different distances and heights from a stream in Pernambuco, Brazil. A total of 2934 specimens of 15 species from five families were collected, mostly collector-filterers. Horizontal flight was limited, with 80% of the abundance concentrated up to 20m. Vertical stratification was also concentrated at lower heights. A female-biased proportion was observed at higher strata. The richness and abundance of species decreased with increasing distances and heights from the stream. Overall, Chimarra sp. and Macrostemum scharfi were the dominant species. Trichoptera is a key taxon used as a biological indicator of water quality, and here, knowledge on the diversity and flight patterns of adults is expanded. At the risk of intensive pollution of rivers in Atlantic forests, data on the adult dispersal can be incorporated in the assessment of endangerment status and in conservation strategies.

Reptiles and amphibians from the fragments of seasonal Atlantic Forest in northern Paraná, Brazil

Amphibians and reptiles play vital roles within intricate trophic networks as predators, prey, pollinators, and seed dispersers, contributing to nutrient cycling and bioturbation. Tropical regions, characterized by their conducive climates, harbor substantial reptilian and amphibian diversity, highlighting their importance for biodiversity conservation. This study endeavors to bridge knowledge gaps by presenting a comprehensive inventory of amphibian and reptile species within the northern region of the Paraná State, Brazil. Employing active searches and acoustic monitoring, we documented 28 species across diverse microhabitats, reflecting ecological diversity. Analyses of abundance, distribution, and diversity revealed comparable trends between dry and wet seasons. Notably, a broad range of generalist species was observed, adapted to varying ecological niches. Our findings emphasize the relevance of detailed faunal inventories to comprehend and manage biodiversity, particularly in understudied regions, contributing to effective conservation strategies in Seasonal Atlantic Rainforest ecosystems.

Germination of aspidosperma discolor a. Dc. Under Different light and Temperature Conditions

Theoretical framework: Among the genera of the Apocynaceae family found in Brazil, Aspidosperma is among the most important, because of its high medicinal and economic value. Objective: The objective of this work was to evaluate the effects of white, far-red, and red light, and the absence of light; as well as the effects of constant temperatures of 25 ºC, 30 ºC and 35 ºC, on seed germination behavior of Aspidosperma discolor A. DC. Method: The material was collected in Atlantic Forest fragments. The germination percentage, speed index, average time and average seed germination speed were evaluated. A completely randomized design was used, and the means were compared by the Tukey test at 95% probability. A 4 x 2 factorial arrangement was used for the evaluation of the light regime (four light regimes and two origins); and for the thermal influence, a 3 x 2 arrangement (three temperature levels and two origins) was employed. Each test had five repetitions with 20 seeds. Results: The results showed that the seeds of both origins presented preferential or neutral photoblastic behavior, with better germination performance at 25 °C. However, they had total germination inhibition when exposed to 35 ºC.

Massive Bird Nest Losses: A Neglected Threat for Passerine Birds in Atlantic Forest Fragments from the Pernambuco Endemism Center

Understanding the mechanisms by which tropical forest fragmentation can affect the persistence of species and populations is of scientific and practical interest. However, nest survival has been one the least addressed of the potentially harmful effects associated with habitat fragmentation, and studies involving nest predator’s identification are still underdeveloped. The Pernambuco Endemism Center (PEC) is the part of the Atlantic Forest located north of the São Francisco River, in northeastern Brazil, where large forest tracts no longer exist and a wave of bird extinctions has occurred recently. Here, we investigated the nest survival of forest understory birds from three PEC fragments (690, 979, and 1036 ha), and we used infra-red camera traps for predators’ identification. Overall, the apparent nest survival was 15.5%, and nest-day-based survival probability for the four more representative species (including two endemic and threatened taxa) were 2.6, 4.4, 6.9, and 18.9%, being 2.7 to 8.5 times smaller than populations or related taxa from the Atlantic Forest of southeastern Brazil. Predators were marmosets (25%), opossums (25%), tegu (19.4%), coati (16.7%), snakes (8.3%), and hawks (5.5%). Jackknife2 model-predicted nest predator’s richness was 20.7 (SD = 1.6). We reinforce the evidence that nest predation associated with fragmentation can affect negatively the bird populations from tropical forests.

Functional Groups of Terrestrial Invertebrates in the Leaf Litter of Atlantic Forest (Bahia, Brazil)

The study conducted in a native fragment of the Atlantic Forest in Alagoinhas, Bahia, Brazil, aimed to evaluate the action of functional groups of terrestrial invertebrates and the effect of seasonality on their biodiversity. Over 6 months, researchers captured 166 invertebrates representing 9 orders and 17 families. The findings revealed a greater abundance of invertebrates (77) at the edge of the forest fragment. However, the indices of diversity, equity, and richness were similar between the fragment's edge and interior. Notably, at the edge, detritivores (such as little armadillos) and predators (including ants and spiders) exhibited dominance over other functional groups like phytophagous, saprophagous, coprophagous, and bioturbators. Predators of the orders Hymenoptera and Araneae were highlighted for their ecological importance, particularly in biological control, especially of detritivores. Interestingly, the study did not observe the effect of seasonality during the brief inventory period. This suggests that other factors may significantly influence the biodiversity of terrestrial invertebrates in the Atlantic Forest fragment in Bahia, Brazil.

Conservation of Manilkara salzmannii in an Atlantic Forest fragment through the study of fruits and seeds

Conservation of Manilkara salzmannii in an Atlantic Forest fragment through the study of fruits and seeds

Factors acting on the floristic variability of the arboreal stratum: a review for the atlantic forest biodiversity hotspot

This study highlights the main factors influencing the distribution and composition of tree species in the Atlantic Forest. It aims to understand the influence of climatic factors in shaping composition patterns, as well as the influence of soil, topography and other environmental factors on the structure and dynamics of this biodiversity hotspot. The results of this systematic review revealed the important contribution of climatic factors such as rainfall and temperature to floristic differentiation in different regions of the Atlantic Rainforest. Edaphic and topographic factors, such as soil pH, soil water stress and altitude, also made important contributions to the distribution of tree species, both locally and on larger scales. Another component identified in the research was the complex interaction of environmental and spatial factors in composition patterns. This is a very recurrent component in the Atlantic Forest, due to latitudinal and longitudinal gradients, where specific ecological conditions create different niches for species. Despite advances, much of the variation in tree species composition remains unexplained, suggesting the existence of unknown factors or limitations in current analytical methods. Thus, this study highlights the need to further explore knowledge about the impact of climate change and anthropogenic activities on Atlantic Forest fragments. In addition, it suggests identifying new determinants and understanding the intrinsic interactions between vegetation and biotic predictors to aid effective management and conservation strategies for this unique and threatened ecosystem.

Impacts of a severe storm on carbon accumulation in coarse woody debris within a secondary Atlantic Forest fragment in Brazil.

The alarming increase in extreme weather events, such as severe storms with torrential rain and strong winds, is a direct result of climate change. These events have led to discernible shifts in forest structure and the carbon cycle, primarily driven by a surge in tree mortality. However, the impacts caused by these severe storms on the production and carbon increment from coarse woody debris (CWD) are still poorly understood, especially in the Brazilian Atlantic Forest. Thus, the goal proposed by the study was to quantify the CWD volume, necromass, and carbon stock before and after the occurrence of a severe storm and to determine the importance of spatial, structural, and qualitative variables of trees in the CWD carbon increment. The increase in carbon by the storm was 2.01 MgC ha-1, with a higher concentration in the CWD less decomposed and smaller diameter class. The forest fragment plots showed distinct increments (0.05-0.35 MgC), being influenced by spatial (elevation, declivity, and slope angle) structural (basal area) and qualitative factors (trunk quality and tree health), intrinsic to the forest. Thus, it is concluded that severe storms cause a large increase in carbon in CWD, making it essential to understand the susceptibility of forests to the action of intense rains and strong winds to model and monitor the future impacts of these extreme weather events on Atlantic Forest and other tropical forests in the world.

Coarse woody debris dynamics in a secondary Atlantic Forest fragment in Brazil

The Atlantic Forest fragments have suffered from the impacts of climate change, resulting in the increased production of coarse woody debris (CWD), which needs to be evaluated in space and time to generate accurate estimates of carbon accumulation. Thus, the goals of this study were (i) to quantify the CWD volume, necromass, carbon stock, and annual increment of carbon (AIcarb) over a period of 4 years; and (ii) to select the optimal combination of climatic, topographic, edaphic, and intrinsic forest variables to accurately predict AIcarb using machine learning and multivariate analysis. The CWD volume, necromass, and carbon stock increased between 2017 and 2020. The AIcarb was 1.09 MgC ha−1 year−1 (2017–2018), 1.24 MgC ha−1 year−1 (2018–2019), and 2.31 MgC ha−1 year−1 (2019–2020). Statistical analysis indicated that climate variables had greater weight in the CWD carbon increment in the 2018–2019 and 2019–2020 periods, while edaphic, topographical, and intrinsic forest variables were more important for the 2017–2018 period. Our findings showed that the carbon increase in CWD was linked to temporal and spatial variables within forests. These results demonstrate the importance of this parameter in the carbon cycle of forest ecosystems and highlight that there should be greater international research efforts to quantify this carbon pool.

Abundance of the bat Sturnira lilium (Phyllostomidae) in relation Solanum mauritianum (Solanaceae) diaspores in an Atlantic Forest fragment of southern Brazil.

Frugivore bats are important seed dispersers in forests and their abundance are associated with the presence of zoochoric plants. In this context, the aim of our study was to investigate the association of the frugivore bat S. lilium with the diaspores of the zoochoric plant S. mauritianum, a common arboreal species present in forest fragments of southern Brazil. We also investigated the diet of the species based on seed content present in feces of individuals. Bats were mist-netted from November 2017 to April 2018 in a fragment of Atlantic Forest. The proportion of immature and mature diaspores of S. mauritianum was estimated in the same area where bats were sampled, and feces were sampled from captured individuals. In total, 61 individuals of S. lilium were captured, and 795 seeds were sampled from their feces. The abundance of S. lilium was significantly associated with the proportion of immature diaspores of S. mauritianum. We identified seeds of two botanical families: Solanaceae (89%) and Moraceae (11%) in the fecal samples. Our findings support the view that S. lilium is a legitimate disperser of S. mauritianum, and that its ecological function is probably a result of co-adaptation.

Dual-polarization vegetation indices for the Sentinel-1 sar sensor and its correlation to forest biomass from Atlantic Forest fragments

Dual-polarization vegetation indices for the Sentinel-1 sar sensor and its correlation to forest biomass from Atlantic Forest fragments

Vapor pressure deficit drives the mortality of understorey woody plants during drought recovery in the Atlantic Forest

AbstractQuestionDrought‐induced tree mortality has been documented in forests worldwide but the mechanisms related to drought recovery are still poorly understood. To better predict forest trajectories under future climate scenarios, it is essential to disentangle physiological mechanisms underlying plant mortality caused by El Niño droughts. Here, we assessed how vegetation structure, vapor pressure deficit (VPD), and functional traits interact to mediate tree mortality after a severe drought in a tropical forest.LocationMata das Flores State Park, an Atlantic Forest fragment in southeast Brazil.MethodsWe established 20 permanent plots with contrasting vegetation structure and topography. In each plot, we measured tree abundance and diameter at breast height (DBH) of every woody plant (1–10 cm diameter) at the end of the drought, and two years after the break of drought, to calculate mortality rates during drought recovery. Hydraulic (e.g., maximum stomatal conductance to water vapor, stomatal density, etc.) and economic traits (specific leaf area, wood density, etc.) were measured on the 10 most abundant species. We also measured local air temperature and air humidity using HOBO dataloggers in each plot to calculate the VPD.ResultsThe studied Atlantic Forest understorey did not recover from the 2014–2016 drought, in terms of tree mortality. Lower VPD, driven by big trees in the valley, protected understorey plants with acquisitive economic attributes and conservative hydraulic attributes against mortality. On the other hand, higher VPD, driven by smaller trees and higher stem density on the ridge and slope, increased the mortality of understorey plants with acquisitive attributes.ConclusionRidges represent the most important fraction of the Atlantic Forest and our results suggest this type of forest is at high climate risk due to global change. Altogether, our results highlight that valleys are microclimate refuges for understorey plants and might help mitigate drought impacts in tropical forest under forecasted climate changes.