Seasonal Semideciduous Forest Research Articles

Acclimatization capacity of leaf traits of species co-occurring in restinga and seasonal semideciduous forest ecosystems

Restingas and seasonal semideciduous forests (SSF) are phytophysiognomies of the Atlantic Forest that have many co-occurring species. However, the microclimatic and edaphic conditions of these phytophysiognomies are quite different. Restingas are characterized by low water availability, high irradiance and temperatures, and sandy and nutrient poor soil, which contrasts with the soil conditions of forests. In this sense, these environmental divergences would have forced species to become acclimatized in order to co-occur in these two distinct environments. The present study aimed to determine the main functional leaf traits that enabled Maytenus obtusifolia, Manilkara subsericea and Inga laurina to co-occur in both restinga and SSF. Morphological, physiological, nutritional and biochemical traits of the leaves of these three species in the restinga and SSF were analyzed. The results showed that in the restinga the species possess thicker leaves with a greater thickening of mesophyll cells; the adaxial and abaxial epidermis and cuticle. In addition, restinga leaves had higher specific leaf mass and greater stomatal density, as well as less leaf area than species in the SSF. The restinga species invested in the biosynthesis of osmoregulatory and photoprotective molecules. Photosynthetic performance was similar between phytophysiognomies for M. obtusifolia and M. subsericea, but I. laurina had lower photosynthetic performance in the restinga. We conclude that the species invested in structural, physiological and biochemical adjustments in the restinga in response to conditions of low water availability and high irradiance.

Diversity and host–parasite interactions of cavity-nesting Hymenoptera communities in the Brazilian Savannah

Cavity-nesting bees and wasps (Hymenoptera: Aculeata) can be good models for studies on ecology, life history, and environmental changes, especially in ecosystem ‘hotspots’ such as the threatened Brazilian Savannah biome. We aim to study the diversity and interaction networks of cavity-nesting wasps and bees as well as their natural enemies in two physiognomies of the Brazilian savannah: woody savannah and seasonal semideciduous forest. Fieldwork was performed in the Uberlândia region, Minas Gerais State, Brazil, from March 2009 to April 2010. Trap-nests made of bamboo canes and black cardboard tubes of two different sizes were set in one sampling station installed in two areas of each vegetal physiognomy. A total of 857 nests of 34 cavity-nesting wasp and bee species were collected; 302 in the semideciduous forest and 555 in the woody savannah areas. The community sampled in the four areas was characterised by few abundant species and several rare species. The alpha diversity was significantly different between the areas, which also presented a low degree of similarity. The interaction network of the community showed a modular pattern with high specialisation degrees, with almost all sampled natural enemy species attacking one host species. The data presented herein demonstrate, at a small regional scale, the importance of both woody savannah and seasonal semideciduous forest areas to maintain a high beta diversity of cavity-nesting bees and wasps and their natural enemies in the Brazilian savannah.

Distribution, threats and conservation of the White-collared Kite (Leptodon forbesi, Accipitridae), the most threatened raptor in the Neotropics

The White-collared Kite (Leptodon forbesi) is an endemic and threatened raptor of the Brazilian Atlantic Forest. Here we present the known records of the species, describe the vegetation types where it was found and show Ecological Niche Models generated using Maxent algorithm. Most of the presence data were recorded in open ombrophilous forest and seasonal semideciduous forest in the states of Alagoas and Pernambuco. Maxent model had a good performance (AUC = 0.982 ± 0.004 SD), showing higher suitability for the species from Paraíba to Alagoas states. Maxent average model revealed a distribution range of 20,344 km² and an area of occupancy of 1,636.89 km². The most suitable areas for the species are those near watercourses and streams. We suggest the creation of protected areas, including private ones, and possible restoration actions to connect the most suitable forest fragments, along with the captive breeding, as the most appropriate strategies for the conservation of the White-collared Kite.

Atlantic forest and leaf traits: an overview

Leaf traits in Atlantic forest are modulated by environmental filters and biotic interactions. More information about leaf traits and nutrient are needed. Categorizing tree species according to their relationships with ecosystem processes in the Atlantic forest (AF) biome is fundamental to better understand their functionality in this high biodiversity hotspot. For categorizing vegetation, leaf traits are extremely useful and this is the first compilation of leaf traits focusing on photosynthesis, water relations, nutrients, and functional diversity across major AF vegetation types: (1) rainforest (ombrophilous dense and mixed ombrophilous Araucaria forest), (2) seasonal semi-deciduous forest, (3) deciduous forests, and (4) coastal plain forests (restingas). Species showed high plasticity of photosynthetic traits from early developmental stages, including adjustments in Rubisco carboxylation capacity, maximum photosynthetic capacity, photochemical and non-photochemical quenching, specific leaf area (SLA), and chlorophyll and spongy parenchyma thickness. Montane rainforest tree species showed lower SLA and longer leaf lifespan in comparison to lowland rainforest species. Tree communities are structured by environmental filtering leading to trait convergence in early successional stages or in stressful ecosystems such as restingas, and by biotic interactions leading to trait divergence in later stages. Altitudinal gradients in litter production and below/aboveground biomass stocks in AF show contrasting patterns in comparison to other tropical forests, with important consequences for responding to climate change. However, the identity of limiting elements to growth still represents a critical gap in leaf trait data for AF species. Other gaps in knowledge of AF leaf traits are highlighted for consideration in future studies.

Tree rings in tree species of a seasonal semi-deciduous forest in southern Brazil: wood anatomical markers, annual formation and radial growth dynamic

Tree rings provide valid predictions regarding species age and growth rates and, therefore, they can contribute to understand forest dynamics and ecology. In this work, we evaluated the tree rings of eight tree species from different successional groups that show distinct degrees of deciduousness in a seasonal semi-deciduous forest located in a transition zone between subtropical and the tropical climates in southern Brazil. We focused on wood anatomical markers, the annual nature of tree-ring formation, the description of false rings, a cross-dating analyses and an interpretation of the radial increment dynamics of the species. We sampled increment cores at breast height, performed cambial wounding and measured tree-ring widths. Annual tree rings were found in seven species, which were confirmed by cambium wounding. Differences in fiber wall thickness between latewood and earlywood and the marginal parenchyma were the main anatomical markers observed. Deciduous species had better distinction of tree ring boundaries, while the evergreen species had slightly distinct tree ring boundaries. False rings were characterized by variations in wood density and axial parenchyma bands of different widths within true tree rings. The annual tree ring confirmation and the anatomical description of the true and false rings are useful for future dendroecological research in the area. Considering the cross-dating analyses and tree-ring distinctiveness, Chrysophyllum gonocarpum is a recommended species. Regarding radial growth, the early secondary species had higher growth rates than the late secondary species. Assessing the growth trajectories over time, distinct patterns were observed among the species: a constant growth, an initial increase followed by a reduction, and oscillations of the growth were observed. As no consistent pattern of the growth trajectories was observed among species that belong to the same successional groups, they contribute to the explanation of the particular life history of these individuals in the seasonal semi-deciduous forest.

Spatiotemporal ecology of two Neotropical herbivorous mammals

On this study, we used camera traps in a Semi deciduous Seasonal Forest, northeast of Brazil, to estimate the frequencies of occurrence of two Neotropical herbivorous mammals: the spotted paca (Cuniculus paca) and the tapeti (Sylvilagus brasiliensis), analyzing their seasonal variations of spatial distribution. We also characterized the activity pattern of the species and their seasonal variation. The herbivorous frequencies of occurrence were constant during all the seasons. In general, both species were mostly active at night. However, between the rainy and dry season, we identified differences in spotted paca activity peaks. Here we present one of the first studies on the tapeti, whose ecology is understudied. Our results also show a general view of the spotted paca and tapeti behavior strategies to seasonal variations. Due to the scarce food resource in the dry season, possibly these herbivorous need to search for different kinds of food available IFS around.

Wood density and carbon concentration of coarse woody debris in native forests, Brazil

BackgroundWith the objective of increasing knowledge on biomass and carbon stocks, and thus improving the accuracy of published estimates, the present study explored wood density and carbon concentration of coarse woody debris (diameter ≥10) by decay class in a Seasonal Semi-deciduous Forest (SSF) area in the Atlantic Rain Forest and in a Cerrado sensu-stricto (CSS) area (Brazilian savanna), in Brazil. Two strata were identified in each area and ten sampling units were systematic located in each stratum. Data were collected according to the line intersect sampling method. Each tallied element, the diameter, length, and perpendicular width were recorded at the transect intersection point. Each element was classified into a decay class, and the species was identified when possible. Sample discs were cut from each element, from which cylindrical samples were extracted and oven-dried to determine density. These cylinders were milled and analyzed using a LECO-C632 to determine carbon concentration as percentage of mass.ResultsIn both areas, wood density decreased as the decay class increased. For SSF the mean carbon concentration of all analyzed samples was 49.8% with a standard deviation of 3.3, with a range of 27.9–57.0% across 506 observations. For CSS the general mean was 49.6% with a standard deviation of 2.6, with a range of 31.2–54.5% over 182 observations. Carbon concentration barely change between decay classes. Carbon stock was estimated at 3.3 and 0.7 MgC/ha for the SSF and the CSS, respectively. Similar results were obtained when using a 50% conversion constant.ConclusionsThe present study concludes that wood density decreases as the woody debris becomes more decomposed, a pattern found in many previous studies. The carbon concentration, however, barely changes between decay classes, and that result is consistent with most of the literature reviewed. Our carbon concentrations are very close to the 50% used most commonly as a conversion factor. We strongly recommend that future studies of CWD evaluate wood density and carbon concentration by decay class to address the uncertainty still found in the literature.

Comparison of the phytochemical profiles of five native plant species in two different forest formations.

The expression of chemical compounds by individual plants of the same species in different locations may be affected by abiotic factors resulting in differences in the production of allelopathic compounds. The objective of this study was to compare the phytochemical profiles of plant species from two different forest formations in the state of Paraná, Brazil. The forest formations were Seasonal Semideciduous Forest (SSF) and Lowland Ombrophilous Dense Forest (LODF), and the five study species were Jacaranda micrantha, Cecropia pachystachya, Mimosa bimucronata, Schinus terebinthifolius and Cedrela fissilis. Secondary metabolites were extracted by exhaustive extraction with methanol, and the crude extract was fractionated using column chromatography. The fractions were used to calculate the retention factor of the main compounds using thin layer chromatography and phytochemical tests. The classes of compounds identified were practically the same among the analyzed species, however, at different levels of concentration. The type of tannins found in S. terebinthifolius differed between the two forest formations.

Orchid bees (Hymenoptera, Apidae, Euglossini) are seasonal in Seasonal Semideciduous Forest fragments, southern Brazil

Seasonal fluctuations in the abundance of orchid bees have already been reported. The variations in population dynamics may be expected to occur in more predictable and pronounced manners in environments with a clear distinction between rainy and dry seasons, where climatic variables are regarded to be good predictors of populational patterns. The main goal of this paper is to investigate the seasonality of males of orchid bees in fragments of Seasonal Semideciduous Forest in southern Brazil. Data comprise bait samples from five one-year periods on four forest fragments. The seasonality of species abundance was tested with circular statistics. Results suggest two phenological patterns, one for Eufriesea violacea (Blanchard), Eulaema nigrita Lepeletier and Euglossa cordata (Linnaeus), whose abundances are concentrated in late spring and early-middle summer and another for Euglossa fimbriata Moure with a tendency to be collected in middle-late summer and early autumn. These patterns are discussed, as well the possible driven factors, (i) the species life cycle and nesting behavior, (ii) synchrony with resource, and (iii) climate. We can postulate an important impact of climate change in local euglossine assemblage due to the small populations and marked seasonality.

ORGANIC MATTER AND SOIL FERTILITY IN DIFFERENT SUCCESSIONAL STAGES OF SEASONAL SEMIDECIDUAL FOREST

ABSTRACT The accumulation and transformation of organic matter in the soil are fundamental for the maintenance and improvement of the chemical, physical, and biological attributes of the soil, and consequently, for the tropical forests functioning. The objective of this study was to evaluate the influence of secondary forests with different successional stages on soil organic matter, carbon and nitrogen stocks, and soil fertility. Three areas of seasonal semideciduous forest, located in Pinheiral - RJ, with different successional stages were selected: initial stage forest - ISF, medium stage forest - MSF, and advanced stage forest - ASF. The values of total carbon and nitrogen, C and N stocks, δ13C (‰) isotope, chemical and granulometric fractionation of soil organic matter, and soil fertility were determined. Based on the values of δ 13C (‰), it was verified that most of the soil carbon of the different successional stages comes from forest species (C3 plants). The areas with the highest succession time (MSF and ASF) possess higher levels of carbon and nitrogen contents and stocks, and carbon associated with minerals compared to ISF. In addition, ASF showed increased phosphorus, fulvic acid, humic acid, whereas soil density exhibited reduced values when compared to that of other areas. The MSF showed, in general, greater fertility of the soil. This study emphasizes the importance of secondary forests that, even in the initial stages of succession, have great potential to store and stabilize organic carbon in the soil.

Medium and large-sized mammals in an Atlantic Forest fragment of Brazil: recording of threatened species

Deforestation and habitat fragmentation affect to a great extent larger wild mammals, which require large areas to establish their populations. These mammals can have important functions in the structure and dynamics of tropical forests, acting as seed dispersers, herbivory regulators, and umbrella species. In the present paper, we characterize the community of medium and large wild mammals in a semi-deciduous seasonal forest fragment, a denominated IB Forest (Institute of Biosciences) in Edgardia Experimental Farm, UNESP, Botucatu, São Paulo State, Brazil. By adopting sand plots on three trails as the main method, we identified the occurrence of nine species, besides the occurrence of one species by direct visualization. Some of these are in national red lists — Leopardus pardalis and Puma concolor are listed as threatened and Sapajus cf. nigritus as Near Threatened in São Paulo State; Puma concolor is also listed as Vulnerable at the national level. Thus, we emphasize the importance of this forest remnant as a wildlife refuge, which makes it necessary to monitor the occurrence of these animals in the area and conserve similar remnants in the region.

Survey of medium-sized and large mammals in semideciduous Atlantic Forest patches near Alfenas, southern Minas Gerais, Brazil

We surveyed, with the aid of camera traps, medium-sized and large terrestrial mammals in 8 patches of semideciduous Atlantic Forest near the city of Alfenas, Minas Gerais, Brazil. We recorded species occurrence using 2 camera traps per fragment, which were simultaneously active for 2 months each. We recorded 16 species, plus a species of armadillo that we were unable to identify to genus. The rarefaction curve tended to stabilize, evidencing the efficacy of our methods. The species richness was similar or higher to other surveys carried out in remnants of seasonal semideciduous Atlantic Forest or transitional areas. However, such seemingly high richness in a severely degraded and fragmented region, including large carnivores and endangered species, hides a wide variation in richness among fragments. This calls for urgent actions to improve the landscape for these animals to ensure their survival in the long term, as some populations are probably not viable in the long run.

Epiphyte-phorophyte relationships: assessing the differences between Seasonal Semideciduous and Swamp Forests in Southeastern Brazil1

ABSTRACT Vascular epiphytes are responsible for a considerable portion of tropical biodiversity; however, the variation of epiphytes-phorophytes relationships in different vegetation types are still poorly understood. In this study, we aimed to assess the presence, abundance, vertical distribution, and life cycle (holoepiphyte and hemiepiphyte) of vascular epiphytes in two vegetation types [Seasonal Semideciduous Forest (- SSF), and Swamp Forest (- SF)] in order to determine any correlation with phorophyte size (diameter and height) and the specificity of phorophyte species to the epiphytic colonization. There was a higher number of phorophytes in SF; however, epiphytes density did not differ between the vegetation types. The recorded vertical distribution also showed different patterns: in the SSF, most epiphytes were found in the canopy, while in the SF they occurred mainly on the trunks of the trees. The abundance of epiphytes was positively correlated with the phorophyte size in the two vegetation types. In the SSF, colonization of phorophytes by epiphytes appeared to be less species-specific than in the SF, where trees density is likely to be a more significant factor to epiphytic colonization. The results showed the importance of the forest heterogeneity in the conservation and maintenance of vascular epiphytes assemblage, demonstrated by differences in the abundance and distribution of the epiphytes, even in contiguous forests.

Wood Volume Estimation in a Semidecidual Seasonal Forest Using MSI and SRTM Data

ABSTRACT The objective of this study was to evaluate the use of the MSI Sentinel-2 and SRTM data to estimate the volume of wood in a Semidecidual Seasonal Forest. Regression equations were fitted based on the remote sensing data, taking into consideration the individual bands and vegetation index of the MSI, elevation values and their derivatives obtained from the SRTM mission and the combination of the data drawn from the MSI and SRTM. RMSE and graphic analysis of residues were used to assess the accuracy of the fitted equations. The best model revealed values of 0.6508 and RMSE of 20.41% in the fit, and of 0.5680 and RMSE of 26.61% in the validation, using the combined MSI and SRTM data as predictors. The volume estimation using spectral data showed satisfactory results, highlighting the importance of topography in the prediction of the volume of wood for the area under investigation.

Competition Indexes to Evaluate Tree Growth in a Semi-Deciduous Seasonal Forest

ABSTRACT Most of the studies that analyze the behavior of tree competition approach even-aged plantations. Therefore, it is possible to notice a lack of this kind of information regarding natural forests with high biodiversity. The objective of this study was to evaluate the competition in a fragment of Semi-Deciduous Seasonal Forest, according to the ecologic group, light depending and non-depending groups for all species sampled in the fragment. The Distance Independent Competition Index and Semi-Distance Independent Competition Index were applied in this study. The basal area in larger trees index, without the radius of influence, was the most efficient to analyze how the competition affects the growth of the specimens in the studied fragment. It was stated that evaluating the competition per ecologic group is more efficient. The results confirm that the forest competition cannot be determined by considering only a fixed radius of influence that embraces the neighbors and the subject tree.

Litterfall Deposition and Decomposition in an Atlantic Forest in Southern Goiás

ABSTRACT Brazilian biomes have been severely threatened and their conservation depends on the knowledge of intrinsic ecological processes and correct phytophysiognomy identification of legal protection purposes. Litterfall deposition and decomposition patterns associated with taxonomic composition, climate, soil and relief can be considered important tools for vegetation typology. This study contributes to classifying the Natural Park of Morrinhos ( Parque Natural de Morrinhos - PNM), a forest fragment in the southern region of Goias, using litterfall deposition and decomposition rates. The results show intense litterfall deposition at the end of the dry period and rapid decomposition in the rainy season (62%), requiring 494 days for total decomposition. The rapid litterfall decomposition rate (k = 1.42 year -1), cumulative annual deposition of 6.43 Mg ha-1 and the taxonomic composition of the vegetation contribute to the classification of PNM as a Semi-deciduous Seasonal Forest.

Edaphic fauna in a vegetation gradient in the Sete Cidades National Park.

The vegetation physionomy and cover can show patterns of diversity and composition of the edaphic community, depending on the quantity and quality of litter in a specific habitat. The objective of this study was to evaluate the effect of the vegetation gradient formed by Graminoid Field (GRF), Cerrado Sensu Stricto (CSS), Cerradão (CRD) and Semideciduous Seasonal Forest (SSF) on density, diversity and composition of the edaphic fauna community in two seasons of the year, in the Sete Cidades National Park (Piauí state). For fauna sampling, a total of eight pitfall traps, distanced 10 m, were placed in each area in the central part of each system, where they remained for seven days. In the wet period, there was a tendency to increase the number of individuals as a function of the complexity of the vegetation formation, with the inverse occurring in the dry period. It was verified an environmental variation of the climatic factors temperature and humidity according to the vegetal formation, contributing to a heterogeneous distribution of the fauna. The GRF formation presented a significantly lower value of average richness only in the dry period. Regarding the variables of diversity and uniformity, they did not show drastic variations in relation to the vegetation gradient studied. The dominant groups in the vegetation gradient were Formicidae, Coleoptera, Aranae, Acari and Collembola, with reduction of the number of Coleoptera in the dry season. Principal component analysis (PCA) revealed greater differences in the composition of the communities between the vegetation formations for the rainy season. At this time, the formations SSF and CRD were associated to a greater diversity of invertebrates than CSS and GRF, demonstrating the influence of the vegetation complexity on the soil fauna community.

The genera Turnera and Piriqueta (Passifloraceae sensu lato) in the state of Pernambuco, Brazil

Abstract A taxonomic treatment of the genera Turnera and Piriqueta in the state of Pernambuco, northeastern Brazil, is presented. Fourteen species of Turnera and six species of Piriqueta were found in the Atlantic Forest and Caatinga, of which nine are endemic to Brazil. Turnera pernambucensis is threatened and restricted to the Atlantic Forest of Pernambuco, while T. joelii is a new record for the state. The species predominate in steppe savanna and semideciduous seasonal forest, but several of them grow naturally in anthropized areas. Catimbau National Park is the locality with the highest species richness. Tristyly is recorded for the first time in Piriqueta guianensis. Identification keys, descriptions, illustrations, distribution maps, and comments about habitat, flowering, fruiting, and morphological relationships are provided.

Soil Microbial Biomass as an Edge Effect Indicator in Semi-Deciduous Seasonal Forest Fragments

ABSTRACT This work had the objective to evaluate the activity and microbial biomass of the soil as an indicator of edge effect in Semi-Deciduous Seasonal Forest fragments. Three fragments of different sizes (small, medium and large) located in the Southwest region of Bahia state were evaluated, in which three sampling ranges were defined in each, and soil samples were collected. The carbon and nitrogen contents of the microbial biomass were determined by the fumigation-extraction method and soil respiration. The microbial biomass carbon (MBC), metabolic carbon quotient (qCO2) and the microbial C:N and MBC:C ratios were discriminating indicators of the edge effect on the soil quality of the studied forest fragments. The integrated analysis of soil microbiological attributes is adequate to evaluate the edge effect in forest fragments. The size of the fragments and their isolation influence the MBC contents, showing greater vulnerability of the smaller fragments in relation to the actions of the external environment.

Anthropic disturbances as the main driver of a semideciduous seasonal forest fragment in Minas Gerais

Abstract The new environmental conditions imposed by disturbance events often create a mosaic of spots in different successional stages. Our objective was to describe the temporal variation of a semideciduous seasonal forest based on its anthropic disturbance history, verifying possible changes in forest dynamics and structure. We sampled the arboreal vegetation with a diameter at breast height (1.3 m above the ground; DBH) ≥ 5 cm in 15 permanent plots of 20 × 20 m where we performed four inventories (2003, 2005, 2007 and 2015). We observed a density decrease and a basal area increase, which indicates the late successional stage of the analyzed tree community. The phytosociological structure, richness and species diversity of the tree community did not show changes throughout the monitoring. However, the Protium spruceanum predominance may be a response to the environmental changes caused by the mining occurred in the area 250 years ago. The anthropic disturbances enduring influences make this type of work indispensable because it allows the ecological processes understanding, allowing a factual management of the forests by the its effective management and conservation.