Floração e frutificação de Myrtaceae de floresta atlântica: limitações ecológicas e filogenéticas

São poucos os estudos que abordam a floração e frutificação em espécies filogeneticamente relacionadas. Myrtaceae é uma das famílias de plantas mais abundantes nas matas brasileiras, em especial na floresta pluvial atlântica. O presente estudo teve como objetivos principais: 1) analisar a fenologia reprodutiva de 38 espécies de Myrtaceae, verificando os padrões fenológicos, relação com os fatores climáticos e previsibilidade das fenofases; e 2) avaliar as teorias propostas para explicar a fenologia de espécies aparentadas e a relação entre a fenologia e o tamanho do fruto. O estudo foi desenvolvido em área de floresta atlântica no Parque Estadual Intervales, Base Saibadela (24°14'08S e 48°04'42W), município de Sete Barras, estado de São Paulo, Brasil. As fenofases botão, antese, fruto imaturo e maduro foram observadas mensalmente durante seis anos nãoconsecutivos (abril/1994 a março/1997 e abril/1999 a março/2002) em 285 indivíduos. As maiores porcentagens de indivíduos e espécies apresentando botões e flores abertas ocorreram sempre na estação mais quente e chuvosa (outubro a março), e produzindo frutos imaturos e maduros principalmente ao longo da estação menos quente e úmida (abril a setembro). As correlações de Spearman foram significativas entre a floração e o comprimento do dia e a temperatura, e correlações significativas foram raras entre a frutificação e o clima. A análise estatística circular mostrou que as datas de início e pico das fenofases reprodutivas em Myrtaceae foram sazonais para a maioria dos anos estudados. Todas as fenofases apresentaram valores altos de previsibilidade de ocorrência...There are few studies approaching flower and fruit patterns among phylogenetically related species. Myrtaceae is one of the most abundant plant families in the Brazilian forests, especially in the Atlantic Rain Forest. The present study had the main objectives: 1) to analyze the reproductive phenology of 38 Myrtaceae species, checking the phenological patterns, the relationship with the climatic factors and the predictability of the phenophases; and 2) to evaluate the proposed theories to explain the phenology of related species and the relation between phenology and fruit size. The study was carried out in an Atlantic forest area at Parque Estadual Intervales, Base Saibadela (24°14'08S and 48°04'42W), municipality of Sete Barras, São Paulo State, Brazil. The phenophases bud flower, open flowers, unripe and ripe fruits were observed monthly for six nonconsecutive years (April/1994 to March/1997 and April/1999 to March/2002) in 285 individuals. The largest percentages of individuals and species presenting buds and open flowers always occurred during the wetter and hotter season (October to March), and unripe and ripe fruits were produced mainly over the less humid and colder season (April to September). The Spearman correlations were significant between flowering and the day length and the temperature, and significant correlations were rare between fruiting and climate. The circular statistical analysis showed that the first date and peak date of the reproductive phenophases in Myrtaceae were seasonal for most of the years. All the phenophases showed high predictability scores... (Complete abstract, click electronic adress below

Fenologia de espécies de floresta atlântica, núcleo Picinguaba, Parque Estadual da Serra do Mar, Estado de São Paulo: comparação entre estratos e influência de borda natural

A sazonalidade na floração, frutificação e renovação foliar das plantas tropicais tem sido investigada em diferentes níveis de organização, de populações a comunidade, revalando grande diversidade fenológica como resposta à heterogeneidade ambiental das florestas tropicais...The seasonality in flowering, fruiting and leafing of tropical plants has been investigated at different levels of organization, from populations to the community, showing great diversity of phenological responses to the environmental heterogeneity of tropical forests... (Complete abstract click electronic access below

Amphibia, Anura, Amphignathodontidae, Gastrotheca albolineata: distribution extension, new state, and new altitudinal records

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Vertical variation in autumn leaf phenology of Fagus sylvatica L. in southern Germany

Phenological variation among trees of different heights provides a small-scale ecological distinction within the forest, allowing the modulation of light interception and, consequently, net carbon gain. While spring phenological variations in temperate forests are well studied, for autumn phenology it is still unclear whether canopy vertical position (exposure), ontogeny or microclimatic factors are more decisive.We observed leaf colouring (LC) and leaf fall (LF) phenology of 166 Fagus sylvatica L. individuals (European beech; Fagaceae), twice/three times a week during autumn 2012 in a mixed forest in southern Germany. We aimed to determine: (1) the extent of variations in leaf senescence among F. sylvatica trees occurring in three different vertical canopy positions in the forest (overstorey, mesostorey and understorey); and (2) whether phenology varies between three different canopy height levels (upper, intermediate and lower). Possible microenvironmental drivers, such as air temperature, air humidity and light, were analysed in relation to autumn phenology. Air temperature and humidity data were obtained from HOBO loggers and light conditions from hemispheric fisheye photographs.Overstorey individuals were the first to start autumn phenology followed by mesostorey and understorey trees. For understorey individuals, the onset of LC and LF were observed 31 and 24 days later than for overstorey trees. The upper canopy parts of individual trees were characterised by the earliest appearance of autumn phases; mean difference in onset date of LC and LF between the upper and lower level was in each case -11 days. As peak dates did not differ, the duration of autumn phases were shorter at the lowest canopy height levels.We find a remarkable phenological avoidance of understorey trees and lower leaves compared to overstorey trees and upper canopy parts in F. sylvatica. We suggest that the observed differences were related to vertical variations in relative humidity and light availability, but also have an ontogenic cue. Since phenological variation in forest stands alters a range of environmental conditions, our study is useful from an ecological and microclimatic viewpoint. Moreover, since phenological development was shown to differ considerably, generalisations are limited when considering trees of different life stages within a forest. Further studies should focus on light conditions to investigate their influence on autumn phenology and importance for phenological avoidance.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

The within-population variability of leaf spring and autumn phenology is influenced by temperature in temperate deciduous trees

Leaf phenology is a major driver of ecosystem functioning in temperate forests and a robust indicator of climate change. Both the inter-annual and inter-population variability of leaf phenology have received much attention in the literature; in contrast, the within-population variability of leaf phenology has been far less studied. Beyond its impact on individual tree physiological processes, the within-population variability of leaf phenology can affect the estimation of the average budburst or leaf senescence dates at the population scale. Here, we monitored the progress of spring and autumn leaf phenology over 14 tree populations (9 tree species) in six European forests over the period of 2011 to 2018 (yielding 16 site-years of data for spring, 14 for autumn). We monitored 27 to 512 (with a median of 62) individuals per population. We quantified the within-population variability of leaf phenology as the standard deviation of the distribution of individual dates of budburst or leaf senescence (SDBBi and SDLSi, respectively). Given the natural variability of phenological dates occurring in our tree populations, we estimated from the data that a minimum sample size of 28 (resp. 23) individuals, are required to estimate SDBBi (resp. SDLSi) with a precision of 3 (resp. 7) days. The within-population of leaf senescence (average SDLSi = 8.5 days) was on average two times larger than for budburst (average SDBBi = 4.0 days). We evidenced that warmer temperature during the budburst period and a late average budburst date were associated with a lower SDBBi, as a result of a quicker spread of budburst in tree populations, with a strong species effect. Regarding autumn phenology, we observed that later senescence and warm temperatures during the senescence period were linked with a high SDLSi, with a strong species effect. The shares of variance explained by our models were modest suggesting that other factors likely influence the within-population variation in leaf phenology. For instance, a detailed analysis revealed that summer temperatures were negatively correlated with a lower SDLSi