Seasonal Deciduous Forest Research Articles

Mixed effects of climate and species richness on aboveground carbon stock in subtropical Atlantic forests

Tropical forests are global biodiversity hotspots and are crucial in the global carbon (C) cycle. Understanding the drivers of aboveground carbon stock (AGC) in a heterogeneous and biodiverse system can shed light on the processes underlying the relationship between biodiversity and carbon accumulation. Here, we investigate how biodiversity, environment, and landscape structure affect AGC. We examined such associations in 349 plots comprising over 95,346 km2 the Atlantic Forest of southern Brazil, encompassing three forest types: Dense Ombrophylous Forest (DF), Mixed Ombrophylous Forest (MF), and Seasonal Deciduous Forest (SF). Each plot was described by environmental variables, landscape metrics, and biodiversity (species richness and functional diversity). We used diversity, environmental, and landscape variables to build generalized linear mixed models and understand which can affect the forest AGC. We found that species richness is associated positively with AGC in all forest types, combined and separately. Seasonal temperature and isothermality affect AGC in all forest types; additionally, stocks are positively influenced by annual precipitation in SF and isothermality in MF. Among landscape metrics, total fragment edge negatively affects carbon stocks in MF. Our results show the importance of species diversity for carbon stocks in subtropical forests. The climate effect was also relevant, showing the importance of these factors, especially in a world where climate change tends to affect forest stock capacity negatively.

A palynological atlas of the Cerrado-Caatinga ecotone in northeastern Brazil

Describing the diversity of Brazilian plant species, as well as the wide variety in the associated pollen grains, is crucial to understanding their evolution and ensuring effective conservation. The accurate identification of pollen is key to successful pollen studies and the consistent paleoecological interpretation of past vegetation changes. Pollen analysts usually identify plant taxa from reference collections built from herbaria material. In Brazil, pollen atlases primarily focus on three main vegetation domains, namely, the Amazon Forest, the Atlantic Forest, and the Cerrado, while information about Caatinga pollen taxa is dispersed across multiple studies; this significantly impedes efforts to further develop palynological research. To address this gap, we built a palynological atlas for the state of Piauí which is covered by the biomes Caatinga and Cerrado along with their transitional zones. These domains encompass various vegetation types, including dense shrubland, grassland, palm swamp formation, riverine forest, seasonal deciduous and semi-deciduous forests, as well as valley-side marshes. We collected flower buds from the Herbarium Prisco Bezerra (EAC) at the Federal University of Ceará and extracted the pollen grains for the pollen reference slides. The atlas comprises 398 species from 99 families, with the most represented families being Asteraceae, Bignoniaceae, Euphorbiaceae, Fabaceae, Lamiaceae, Malvaceae, Malpighiaceae, and Rubiaceae. Each taxa is presented with a description of the pollen grain, a photo showing polar and equatorial views, and ecological information as life form (liana/scandent/vine, herb, subshrub, shrub or tree), substrate, and vegetation type to support further studies.

New records to Odontadenia hypoglauca (Apocynaceae) in Brazil

Odontadenia hypoglauca is a species of Apocynaceae previously recorded only in the Cerrado and ombrophilous forest vegetation types, in the Cerrado and Amazon and Atlantic Forest domains, respectively, in Brazil and Bolivia. In this paper, we show new records of the species for the states of Maranhão, Piauí and Tocantins, thus expanding its known distribution in Brazil to the caatinga and seasonal deciduous forest vegetation types, in the Caatinga and Atlantic Forest domains. In the state of Piauí in particular, this is also the first record of the genus Odontadenia. In addition to reporting these new records, we provide a description for the species, photographs, geographic distribution, taxonomic comments, conservation status, map, and an identification key for the species of Odontadenia that occur in the aforementioned states and other morphologically related species.

Plants of the Serra do Mucambo: a checklist of a remnant of deciduous seasonal forest within the Caatinga domain in Bahia, Brazil

Plants of the Serra do Mucambo: a checklist of a remnant of deciduous seasonal forest within the Caatinga domain in Bahia, Brazil

Bird checklist and contributions to conservation of the Atlantic forest-cerrado ecotone in Três Lagoas municipality, Brazil

Although Três Lagoas municipality is located in a rare and highly fragmented Atlantic Forest-Cerrado ecotone, there is scarcity of biodiversity data to guide conservation decisions. Therefore, this study aimed to compile the first bird checklist in 31 localities in this municipality to propose conservation strategies based on avian richness, conservation and migratory status. A total of 419 bird species were recorded, of which 412 were exclusive to the Atlantic Forest-Cerrado ecotone and seven to the Cerrado domain (C. minor, L. xenopterus, P. unicinctus, T. curucui, S. pileata, S. melanopis and S. luteola). According to the results, 12 species are included in the Near Threatened category, four are vulnerable (C. fasciolata, L. xenopterus, A. tricolor and S. hypoxantha) and one is endangered (U. coronata). Regarding migratory birds, 112 were recorded (95 intracontinental, 17 intercontinental). Since the majority of these species are recorded in grasslands, aquatic habitats and Seasonal Deciduous Alluvial Forest, they necessarily have highest priority for conservation and restoration. Thus, we recommend that: (1) areas 2, 11 and 24 be considered as both Important Bird Area and “Area de Proteção Ambiental”; (2) riparian forest restoration along the Paraná river act as a local ecological corridor among these areas, allowing the recolonization, genetic exchange and restoration of locally reduced populations of migratory and near/threatened bird species.

A new species of Rhynchospora section Pluriflorae (Cyperaceae) from the southwestern edge of the Brazilian Amazon

ABSTRACT A new species of Rhynchospora (Cyperaceae) only known from the Parecis plateau, on the southwestern edge of the Brazilian Amazon, is described here. Rhynchospora parecisensis was found growing only in open environments of deciduous seasonal forest and savanna enclaves in the midst of seasonal evergreen forest, in the state of Mato Grosso, western Brazil. Rhynchospora parecisensis differs from the other species of Rhynchospora sect. Pluriflorae subsect. Subebracteatae by the distally puberulent to pubescent glumes. The new species resembles Rhynchospora acanthoma, but differs from it by the subtriangular to quadrangular scapes in cross-section and the distally puberulent to pubescent glumes, with ciliate to ciliolate margins. Taxonomic comments, illustrations and a distribution map are also provided.

The Brazilian semiarid region over the past 21,000 years: Vegetation dynamics in small pulses of higher humidity

In South America, one of the least addressed regions in paleoecological studies is the Brazilian Semiarid region, composed of vegetation from different biomes and currently marked by an arid climate. Although environmental conditions do not favor the formation of palynological sites, previous studies have indicated an expansion of savanna vegetation during the Last Glacial Maximum (LGM). However, more refined analyses with better spatial and temporal resolutions are important for a better understanding of these environments. The region's past reconstructed by models is related to intense climate changes on brief time scales in the Pleistocene and Holocene. Furthermore, paleoclimatic modeling reconstructions that only reproduce atmospheric conditions do not always represent all factors for vegetation formation and dynamics through time. In this work, we aimed to use the combination of bioclimatic and edaphic predictors to build models with machine learning algorithms capable of predicting the current and last 21,000 years' vegetation. Our results show that there is a significant gain in precision in the classification of vegetation formations when edaphic predictors are added. The use of subsurface horizons to generate edaphic attributes also resulted in better details of the local distribution of vegetation. The reconstruction of the past climate showed that the greatest change was promoted during the Heinrich Stadial 1 period; with the retraction of areas of open vegetation formations of the Hyperxerophilous Caatinga, areas of Arboreal Caatinga, Forested Caatinga, and Seasonal Deciduous Forest advanced. The current vegetation cover was established only in the Late Holocene, a period in which the humid conditions of the region allowed occupation by mostly dry vegetation.

Influence of dry season on social wasp communities (Hymenoptera: Polistinae) in Deciduous Forest

The seasonal deciduous forest, also known as dry forest, is characterized by the deciduity of tree species and two well-defined seasons which cause drastic changes in its physiognomy, and the seasonality of rainy periods directly impacts the forest’s biological communities. Social wasps (Vespidae: Polistinae) are well documented. However, some ecosystems in which they occur, such as the deciduous forest, are still subsampled. This study aimed to assess the response of social wasp communities to the dry season in a deciduous forest in the Mata Seca State Park, in the North of the state of Minas Gerais, Brazil. Insects were collected over 24 days divided into four field campaigns, each with six continuous days of collection (February, May, July, and November 2021), encompassing one campaign per season. All specimens were sacrificed and stored in 70% alcohol and later dry mounted for identification. The Kruskal-Wallis (KW) H test was performed to verify the difference between species richness, number of total colonies, and number of colonies of each tribe in relation to the collection station. In total, 131 colonies of eight species were located, particularly Polybia occidentalis (Olivier, 179), with 39 colonies, Polistes versicolor (Olivier, 1791), with 33, Mischocyttarus cassununga, with 21, and Protonectarina sylveirae (Saussure, 1854), with 13. Six species, five of which were from the Epiponini tribe, were collected in the four seasons. The responses of social wasps to the periods of drought in the deciduous forest vary with tribe. While Epiponini populations can keep colonies active in the dry season, Polistini cannot. Meanwhile, P. versicolor responds positively to the onset of the rainy season, increasing its population.

Effects of Deciduous Forests on Adolescent Emotional Health in Urban Areas: An Example from the Autumn Ginkgo Forest in Chengdu

Many studies have shown that urban green spaces can promote emotional health. Deciduous forest is an important landscape and ecological resource of the city. However, the emotional impact of different behavior patterns in this kind of natural space with obvious seasonal changes are rarely discussed. This study explores the emotional feedback of two typical behavior patterns within an urban landscape forest in autumn: sitting and walking. We recruited 80 volunteers and divided them into a sitting viewing group (group S) and a walking viewing group (group W). On the premise of gender balance, they were randomly assigned to a natural path under a Ginkgo biloba forest in autumn for 15 min of viewing. Physiological and psychological indicators were used for monitoring. Blood pressure, heart rate and electroencephalography (EEG) were used for physiological indicators, and a POMS questionnaire was used for psychological indicators. A paired t-test and one-way ANOVA were used to analyze the physiological parameters of the two experimental groups, and a paired Wilcoxon signed-rank sum test was used to analyze the differences in psychological indexes between the two behavior groups. The results showed that the diastolic blood pressure and pulse of the sitting group decreased significantly under the seasonal deciduous forest, and the walking group attained higher “Engagement”, “Excitement”, and “Relaxation”. In the absolute α and β waves, there were significant differences in the parietal P8 channels between the sitting and walking groups, and significant differences in the RAB indicators of the AF3, F7, P7, FC5, FC6, F3 and T7 channels. The two behavior patterns can effectively reduce negative mood, and the “Vigor” mood in the walking group was significantly increased, which was significantly better than that of the sitting group in reducing negative mood. These results enrich research on the influence on emotional health in the field of seasonal green-space restoration. The differences of different behavior patterns can provide guidance for planning urban landscape forest construction and activity facilities.

Atlantic Forest Ecosystems: Are There Significant Differences When Compared at the Same Stage of Regeneration?

For the monitoring and assessment of Atlantic Forest ecosystems, key indicators of the regeneration stage are considered. However, the current classification of these stages by experts does not consider the possible differences among such ecosystems. In order to test the hypothesis of significant differences, Atlantic Forest ecosystems in southern Brazil were compared at the same stage (initial, medium, and advanced stages of regeneration). An extensive database of the floristic forest inventory of Santa Catarina state, southern Brazil, with 460 sampling units, was used, addressing the seasonal deciduous forest (SDF), dense ombrophilous forest (DOF), and mixed ombrophilous forest (MOF). The regeneration stage of each sample unit was previously classified by experts using five key indicators (basal area per hectare—BA/ha; number of individuals per hectare—N/ha; number of species—S; Shannon biodiversity index—H’; and diameter at breast height—DBH). The Kruskal–Wallis method and pairwise multiple comparisons based on Dunn’s procedure were applied, considering two-way tests with 5% significance, and 95% power. The statistical tests confirmed the research hypothesis, namely, that the key indicators had significant differences in the later regeneration stages of Atlantic Forest ecosystems. For instance, S in DOF was statistically higher (p < 0.001) than in MOF and SDF (44 ± 9); N in SDF was significantly lower (394 ± 248 at mid-stage) compared to MOF (475 ± 233) and DOF (545 ± 173); and H’ showed increasing differences towards more advanced stages. Considering that the stage of forest regeneration is the main criterion for decision-making between suppression and conservation of forest ecosystems, the results achieved should support the review of current procedures applied to the classification of successional stages. Given the demonstrated differences, in the next steps of research, we will evaluate and propose specific standards for each Atlantic Forest ecosystem, i.e., intervals of discriminating values for the key indicators applicable to this biome.

Potential cultivation areas of Euterpe edulis (Martius) for rainforest recovery, repopulation and açai production in Santa Catarina, Brazil

Euterpe edulis is an endangered palm species that provides the most important non-timber forest product exploited in its natural habitat, the Brazilian Atlantic Forest hotspot1,4. From 1991 to 2017, pasturelands, agriculture, and monoculture of tree plantations were responsible for 97% of Atlantic Forest deforested areas in Brazil and Santa Catarina was one of the Brazilian states with the greatest loss of forest area14. In the last decade, E. edulis fruits reached their highest commercial value, producing the southeastern equivalent of Amazonian ‘‘açai’’ (Euterpe oleracea)5,7,8. As a shade-tolerant species, E. edulis adapts very well to agroforestry systems8,10. To evaluate potential areas for cultivation of E. edulis through agroforestry systems, we developed and applied a spatial model for mapping suitable areas. To accomplish this, we analyzed multisource biophysical data and E. edulis distribution data from the Forest Inventory of Santa Catarina. We identified two areas with potential occurrence of the species, one in the domains of coastal Dense Ombrophilous Forest where the species is more common and another in the domains of inland Deciduous Seasonal Forest where its occurrence was suspected, but not proven, until 2021. Today, Deciduous Seasonal Forest is the most fragmented and impacted by agriculture. Our model, together with confirmed areas of occurrence, indicates that deciduous seasonal forest region should be prioritized for production and recovery of E. edulis through agroforestry systems.

Characterization of entomogenic galls in areas of seasonal deciduous forest in Southwestern Bahia, Brazil

Galls are small structures induced mostly by insects in different plant organs, and have different shapes and colorations. Knowledge on galls is still sparse in the semiarid region of Bahia. Therefore, the goal of this study was to characterize galls in fragments of seasonal deciduous forest. Sampling was performed in the Bahia municipalities of Boa Nova, Jequié, Poções and Vitória da Conquista. In each site, one fragment was chosen, and in each fragment, plots were established to survey galls on vegetation. We sampled 158 gall morphotypes, representing 49 (morpho) species distributed across 15 families of host plants. Myrtaceae and Malphigiaceae had the highest numbers of gall morphotypes. Most galls were collected from leaves, whereas the most common gall morphotypes were globoid and fusiform.

Diametric Structure of One Fragment of One Deciduous Seasonal Forest in Brazilian Savanna Eco Museum

Diametric Structure of One Fragment of One Deciduous Seasonal Forest in Brazilian Savanna Eco Museum

FLORISTIC SIMILARITY IN A FOREST-SAVANNAH ECOTONE IN WESTERN BAHIA STATE, BRAZIL

This study aimed to generate knowledge about transition areas between phytophysiognomies for the understanding and conservation of these unique environments. Thus, the existence of different floristic groups was analyzed in a spatial gradient of an ecotone in the municipality of São Desidério, state of Bahia, Brazil. To this end, a transect of approximately 4.7 km, with orientation from Northeast to Southwest, was established along a spatial gradient. Twelve (12) 10x50 m sampling plots (500 m² each) were distributed throughout this transect. The following methodology was employed: First, the floristic similarity between the sampling plots was measured. These sampling plots were then grouped and the data were graphically presented in a dendrogram (Cluster analysis) and an ordering diagram (nMDS). Finally, the phytosociological parameters by ordered group were obtained. The results showed the presence of three floristic groups: Groups I, II and III, classified as wooded savannah, seasonal deciduous forest, and forested savannah, respectively. The floristic groups were formed gradually along the spatial gradient, and transition between phytophysiognomies does not occur abruptly, since the ordering by groups is more due to the difference between the abundance of species than to their presence and/or absence. The distribution pattern of the phytophysiognomies along the spatial gradient indicates association with abiotic factors, such as the pedological characteristics and the relief found along the transect, possibly creating an environmental gradient.

Diversity of solitary wasps (Vespidae, Eumeninae) in Decidual Seasonal Forest in the state of Minas Gerais, Brazil

Eumeninae is the subfamily with the highest number of species among Vespidae family, with more than 3,750 species and 210 genera identified worldwide. Some ecosystems are subsampled, such as the decidual seasonal forest, also known as dry forest. Thus, this study aims to execute the inventory of the Eumeninae community in decidual seasonal forest in the Parque Estadual da Mata Seca, Minas Gerais. The study took place from February to December 2021, executing active search and using malaise traps. A total of 90 individuals, belonging to 30 species, was collected, which characterize this study as the fourth highest list of Eumeninae for Brazil, even with a smaller sampling effort than other similar studies. In this study, 40% of the collected species are rare, having been collected only once. The most abundant species were Pachodynerus brevithorax (Saussure, 1853), Hypalastoroides brasiliensis (Saussure, 1856), Pachymenes ater (Saussure, 1852) and Montezumia petiolata (Saussure, 1855). This research shows how the Neotropical Eumeninae fauna is still little explored, indicating the need for more research to be conducted with this taxon, especially in environments without exploration such as the decidual seasonal forest.

An Empirical Study of the Restoration Potential of Urban Deciduous Forest Space to Youth.

Urban deciduous forests are an important ecological resource and seasonal landscape in the urban environment. However, in the abundant literature on how urban green space promotes human health and well-being, research on urban seasonal deciduous forests is limited. This study aimed to investigate the physiological and psychological recovery potential provided of urban deciduous forest space for youths and the spatial preferences of youths regarding such spaces. We recruited 120 participants to study the restorative potential of two typical urban deciduous forest landscape spaces (experimental groups) and one urban road environment (control group). The results showed that after 15 min of observation, the blood pressure (especially the diastolic blood pressure (p < 0.01)) and pulse of the deciduous forest trail setting (DFTS) group effectively decreased, and the restorative mood significantly increased. Regarding change in emotional parameters, the DFTS group scored higher on “interest” and significantly higher than the other two groups on positive emotion. The correlation results show that density and level are the key factors affecting spatial preferences regarding complex deciduous forests. An increase in density reduces the mood of re-laxation, and an increase in level decreases fatigue and interest. We suggest (1) constructing foot-paths in urban deciduous forests to reduce their spatial density as to improve the relaxation effect and (2) increasing landscape diversity according to the forest space to facilitate user participation and interest. This study provides a scientific basis for the environmental restoration of deciduous landscapes and for urban forestry management decision-makers based on space type construction.

Does the functional leaf anatomy of Justicia calycina (Acanthaceae) reflect variation across a canopy gradient in the Southern Brazilian Amazon?

Justicia calycina is a subshrub well distributed in northern South America. Despite its widespread occurrence, little is known about its anatomy and plasticity in different environments. Our study aimed to evaluate how leaf anatomical traits of J. calycina adjust in forest areas with variations in canopy openness in the Southern Amazon, Mato Grosso State, Brazil. Forest areas were: Open and Dense Ombrophilous Forest, and Seasonal Deciduous Forest (rocky outcrop). We performed anatomical measurements in leaves sampled on 10 individuals in each forest site, with the help of usual anatomy techniques. Foliar anatomy of J. calycina showed similar pattern among the studied forests, with significant difference (p<0.05) in four leaf traits among 22 studied: vascular bundle diameter, palisade parenchyma thickness, stomatal density and trichome density in adaxial epidermis. These leaf traits showed high plasticity index, with higher values in Dense Forest and in Deciduous Forest. Even though J. calycina showed overall little anatomical variation among forest types, the few attributes that differed are fundamental in the photosynthesis process. The adjustment in leaf anatomical traits under different luminosity conditions demonstrates a degree of phenotypic plasticity in the species, which contributes to its distribution in different forest phytophysiognomies in Brazilian Amazonia.

Novidades do estrato herbáceo em uma região chave para a conservação da Amazônia Meridional

Abstract The contribution of the herbaceous stratum to tropical plant diversity is considerable, however this component remains undersampled. We investigated floristic, structural, ecological and conservation issues concerning the herbaceous component of a seasonal deciduous forest associated with granitic rock outcrops in the Cristalino Region, a key area for biodiversity conservation in the Brazilian Amazon. We installed a permanent plot of 1 ha, allocating 10 transect-lines of 20 m each. We identified the sampled individuals, measured height and projection, and verified cover and frequency per species, genera and family. We recorded 86 species, 62 genera and 25 families, with Orchidaceae being the family with the highest species richness. Among the 26 new species added to Cristalino Flora, we included Philodendron deflexum Poepp. ex Schott and Griffinia nocturna Ravenna, the latter ‘Critically Endangered’. Furthermore, the occurrence of G. nocturna in an Amazonian forest matrix is a novelty in this study. The estimate of species diversity according to Shannon-Wiener (H’) was 2.43 nats.ind.-1 (equivalent to 11.37 ± 0.90 IC95% equally common species), and according to Simpson (1/D), 6.82 (± 0.648 IC95%). The rarefaction and extrapolation curves for the diversity estimates tended to stabilize. Although the vegetation on rock outcrops usually presents a high number of endemic species, this pattern was not found in our study area, which can be explained by its continuous occurrence in the forest matrix. The understory of our study area consists in a mixture of floras, being composed mainly of species from the Amazon and/or Cerrado biomes. In view of the current anthropic pressure faced by the southern Amazon, we reinforce the importance of carrying out inventories of its herbaceous communities, since the risk of species loss is even more alarming when considering present undersampling of this component.

Tree component analysis in a savanna-forest ecotone area of Minas Gerais state, Brazil

Ecotones are transition areas characterized by environmental complexity and high biodiversity. In this sense, carrying out a floristic survey and characterization of each phytoecological region is necessary. Thus, we analyzed the floristic composition, horizontal and vertical structure, and dispersal syndromes of the woody community in an ecotone of cerrado sensu stricto and seasonal deciduous forest. Likewise, we proceeded with the floristic similarity analysis to evaluate the study area’s similarities to the vegetation of cerrado sensu stricto and seasonal deciduous forest. A total of 919 individuals from 19 families, 43 genera, and 49 species were sampled. The tree community has an average height of 4.12 m, a species diversity of 3.03 nats.ind-1, and a Pielou equitability index of 0.77. The predominant dispersion syndrome was anemochory. The vegetation formed floristic groups with the cerrado sensu stricto. The environmental gradient that determines the occurrence of transition vegetation makes each remnant unique in terms of species and structure, demonstrating the importance of these areas for the biodiversity conservation.

Genetic and chemodiversity in native populations of Schinus terebinthifolia Raddi along the Brazilian Atlantic forest

Schinus terebinthifolia is a species native to different ecoregions in the Brazilian Atlantic Forest. The plant is listed on the National Relation of Medicinal Plants and recommended as phytomedicine, however while extractive exploitation prevails as the main route of raw material a significant variation of compounds will be detected. To assure the expansion of productive chain it is important to start by studying population diversity and chemical variations. We used SSR markers for studies of genetic structure among populations from dense ombrophilous forest (ES); the deciduous seasonal forest (SM); the savanna (DOU) and the sandbanks (ITA and MSP), and compared the results to their chemical profiles of essential oil. Genetic structure revealed differences among populations and significant fixation rates. Pairwise studies and Bayesian analysis showed similarities between ITA and SM and between DOU and MSP, proving that the patterns of distribution for the species do not follow the isolation by distance or similarity by environmental conditions. The comparison between PCA of genotypes and chemodiversity reinforces the unique profile for each population despite the environmental similarity observed and genetic analysis. The most divergent genotype and chemical group was found at the ombrophilous forest, strong evidence that we should undertake conservation efforts to prevent losses of biodiversity in that area.