The deciduousness of tropical trees and communities depend on ecosystems characteristics such as plant species diversity, and strength of the dry season. Based on seven years of phenological observations, we provide the first long‐term description of leafing patterns of a woody cerrado community, aiming to investigate (1) the leaf exchange strategies considering the interannual variation in the degree of deciduousness of individuals and species and quantify the community deciduousness; (2) the relationship between interannual patterns of leaf fall and leaf flush according to the species’ leaf exchange strategies and climate; (3) the onset of cerrado growing season and its relation to climate seasonality. To detect seasonality and leafing onset we applied circular statistics and to understand the relationships between environmental predictors and leaf exchange strategies, we used generalized additive models. From 106 species observed, we classified 69 as deciduous (26 species), semi‐deciduous (25) or evergreen (18) and defined the studied cerrado as a semi‐deciduous vegetation. Leaf phenology was markedly seasonal and similar among years. Leaf fall peaked in the dry season, and leaf flush in the dry‐to‐wet transition. Leaf fall patterns related to temperature and leaf flush to day length and rainfall. Semi‐deciduous and deciduous species were more constrained by climate than the evergreen ones. The cerrado growing season started in the dry‐to‐wet season transition. Interannual variations in rainfall and temperature affected the individuals’ and, consequently, species’ degree of deciduousness, highlighting individual and species variability, and suggesting that cerrado leafing patterns are likely susceptible to future climate change scenarios.
The Brazilian cerrado has undergone an intense process of fragmentation, which leads to an increase in the number of remnants exposed to edge effects and associated changes on environmental conditions that may affect the phenology of plants. This study aimed to verify whether the reproductive phenology of Xylopia aromatica (Lam.) Mart. (Annonaceae) differs under different light conditions in a cerrado sensu stricto (a woody savanna) of southeastern Brazil. We compared the reproductive phenology of X. aromatica trees distributed on east and south cardinal faces of the cerrado during monthly observations, from January 2005 to December 2008. The east face had a higher light incidence, higher temperatures and canopy openness in relation to south face. X. aromatica showed seasonal reproduction at both faces of the cerrado, but the percentage of individuals, the synchrony and duration of phenophases were higher at the east face. The study demonstrated the influence of the environmental conditions associated to the cardinal orientation of the cerrado faces on the phenological pattern of X. aromatica. Similar responses may be observed for other species, ultimately affecting patterns of floral visitation and fruit production, which reinforces the importance of considering the cardinal direction in studies of edge effects and fragmentation.
-(Structure and floristic composition of a Cerrado sensu stricto and its relevance to ecological restauration). Edges are transition areas between two adjacent ecosystems that can be originated by natural or anthropogenic events. The edge influence includes both direct effects, related to changes on microenvironmental factors, as well as indirect effects, related to changes in species interactions. Additionally, some studies suggest that microenvironmental factors are altered by the cardinal orientation of the edge. The present study aimed to evaluate the influence of edge on microenvironmental factors, local soil conditions, woody vegetation structure, and species richness in a Cerrado sensu stricto at Itirapina, São Paulo State, Brazil. Specifically, we investigated whether microenvironmental factors (relative humidity (%), photosynthetic active radiation (PAR), temperature and percentage of canopy cover), soil conditions and vegetation composition differ among plots (36 plots of 25 × 2 m spaced 50 m apart) distributed on the edge and in the interior, facing east and south sides of the Cerrado. We sampled all woody trees and treelets with circumference ≥ 3 cm at 30 cm from its ground base within each plot. The microenvironmental variables relative humidity, PAR (photosynthetic active radiation), temperature and percent of canopy openness, and the soil samples (0-20 cm deep) for nutrients and texture analyses, were all collected at three points within each plot. We recorded a total of 120 woody species distributed among 40 plant families. Among the structural parameters of vegetation, only the absolute density was significantly higher in the interior south of the Cerrado. The microenvironmental factors were significantly different between the east and south sides, but did not differ between edge and interior. Therefore, based on the environmental and structural parameters we evaluated, there was no evidence of edge influence in the Cerrado studied. However, the east and south faces and associated microenvironmental factors, and the presence of some nutrients in the soil, such as Mn, affected the Cerrado vegetation structure and species composition. Our results highlight the importance of taking into account the cardinal orientation in addition to the soil nutrient and microenvironment parameters to better understand the factors influencing the vegetation at a local scale. Key words: diversity, edge influence, microclimate, savanna, similarity, species richness RESUMO -(Estrutura e composição florística de um Cerrado sensu stricto e sua importância para propostas de restauração ecológica). Bordas são áreas de transição entre dois ecossistemas e podem ter origem natural ou antrópica. A influência de borda inclui tanto os efeitos diretos, relacionados às alterações microambientais, como os efeitos indiretos que afetam as interações entre espécies. Adicionalmente, estudos sugerem que a orientação cardinal pode modificar os efeitos microambientais da borda. O objetivo deste estudo foi avaliar a influência d...
Phenological studies are important to the understanding of the dynamic of forest ecosystems, especially when they evaluate the availability of fruits to the fauna. The gallery forests occur along water streams and play an important role as natural corridors, allowing the gene flow and connecting populations isolated due the forest fragmentation. The present study aimed to understand how the reproductive phenology and the fruit availability of gallery forest species changes between seasons and over the year. Monthly observations were carried out on 29 plant species, 31% wind dispersed and 69% animal dispersed, from the gallery forest of Formoso River, Bonito Municipality, Mato Grosso do Sul, Brazil. Flowering occurred in the transition from dry to wet season, and fruiting mainly during the wet season, but did not present significant correlation to rainfall or temperature, regardless the seasonal pattern. The species Attalea phalerata and Guibourtia hymenifolia accounted for most of the fruit production in the dry season, supplying food resources to frugivores during this period of fruit scarcity.Key words: Anemochory, frugivory, gallery forest, phenology, seed dispersal, zoochory. ResumoEstudos fenológicos são importantes para o entendimento da dinâmica dos ecossistemas florestais, principalmente quando avaliam a disponibilidade de frutos para a fauna. As matas ciliares são formações vegetais que ocorrem ao longo dos cursos d'água e desempenham papel importante na formação dos corredores de fluxo gênico, podendo interligar populações vegetais que foram separadas pelo processo de fragmentação. O presente trabalho procurou entender como varia a fenologia reprodutiva e a disponibilidade de frutos de espécies arbóreas em mata ciliar do rio Formoso, município de Bonito, Mato Grosso do Sul, entre estações e ao longo de um ano. Foram feitas observações mensais em 29 espécies vegetais, 31% anemocóricas e 68,9% zoocóricas, das fenofases floração e frutificação, e estimada a produção de frutos por contagem no chão da floresta. A floração ocorreu principalmente na transição entre as estações seca e chuvosa e a frutificação na estação chuvosa e não apresentaram correlações significativas com a pluviosidade ou a temperatura, apesar do padrão sazonal. As espécies Attalea phalerata e Guibourtia hymenifolia destacaram-se pelo fornecimento de frutos para a fauna de frugívoros na estação seca, período de maior escassez de frutos na mata ciliar. Palavras
The Brazilian savanna is a mosaic of phytophysiognomies influenced by edaphic and topographic factors that range from the occurrence of fires to anthropic disturbance. The goal of this study was a comparative analysis between two cerrado areas in southeastern goiás, relating the floristic composition and structure of the vegetation to soil properties to better understand the physiognomic characteristics of the region. Twenty-five 20 × 20 m plots were used. All plants with circumference at breast height of more than 15 cm were measured. Soil samples collected at a depth of 0-20 cm were subjected to physical and chemical analyses. canonical correspondence analysis (cca) was used to detect possible correlations between the soil properties and species abundance and distribution. The density and total basal area were 1,647 ind/ha and 15.57 m 2 /ha, respectively, in Ouroana. At this site, 107 species were sampled. In Montes Claros de Goiás, the density and total basal area were 781 ind/ha and 17.62 m 2 /ha, and 120 species were sampled. The soil texture of Ouroana was sandy and significantly different from the medium to clayey texture of Montes Claros. The soils of both areas are dystrophic, however, more fertile in Montes Claros and aluminum-toxic in Ouroana. The species of vegetation were distributed according to soil fertility levels. The CCAs grouped species according to soil properties that defined location and abundance as well as the phytophysiognomies of the studied areas.
Anacardium occidentale (Anacardiaceae) is a species of great economic importance for Brazil and several other countries due to its food and medicinal uses. However, studies describing its reproductive phenological cycle are scarce. For this reason, this study aimed to describe the reproductive phenology of A. occidentale in Montes Claros de Goiás, state of Goiás, Brazil. Between June 2012 and July 2015, the phenophases of flower budding, anthesis, underripe fruit and ripe fruit were recorded monthly using the Fournier scale. Data were analyzed using the Fournier index, absence/presence method, and circular statistics. The data were correlated with the average, maximum, and minimum temperatures and the precipitation of the study area. Flowering and fruiting were synchronous in the dry season, and the two events ended with the onset of rainfall, resulting in a significant negative correlation between flowering and precipitation (rs =-0.73) and a significant positive correlation between fruiting and average temperature (rs = 0.70) and between fruiting and maximum temperature (rs = 0.41). The minimum temperature influenced when anthesis (rs =-0.64) and underripe fruit (rs =-0.37) would occur. The reproductive phenological events of A. occidentale are closely related to the climatic data of the studied area. A. occidentale presents reproductive strategies for species perpetuation in the study area.
Estudos fenológicos são importantes para a compreensão da dinâmica das comunidades vegetais, para o entendimento da reprodução das espécies, da organização temporal dos recursos e da coevolução entre plantas e animais. Neste estudo, acompanhou-se a fenologia vegetativa e reprodutiva de 22 indivíduos de Annona coriacea Mart., durante 11 meses, em um fragmento de Cerrado sensu stricto no município de Rio Verde, Goiás, registrando-se os índices de atividade, intensidade e avaliando-se a sincronia das fenofases. A ocorrência da floração e brotamento no início das chuvas, a manutenção da produção de folhas adultas durante todo o período estudado e a maior intensidade de frutificação e senescência foliar durante a estiagem são estratégias características de uma planta adaptada à ocorrência de duas estações bem marcadas. Dessa forma, há indícios de que Annona coriacea responde à sazonalidade climática característica do Domínio Cerrado, já que a delimitação dos padrões fenológicos e da sazonalidade só é possível a partir de pelo menos dois anos de dados.
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