Partição de nicho por grupos funcionais de espécies arbóreas em uma floresta subtropical

Abstract

ResumoO presente estudo teve como objetivo investigar a variação de atributos funcionais de espécies arbóreas ao longo de diferentes posições topográficas, em uma floresta subtropical na região do Alto Uruguai, em Santa Catarina. Para as 20 espécies mais abundantes na área amostrada, foram determinados densidade básica da madeira (WD), altura potencial (Hmax), área foliar (LA), área foliar específica (SLA), regime de renovação foliar, guildas de regeneração e de dispersão. A estrutura funcional foi avaliada por meio dos valores dos atributos funcionais por parcela, ponderados para a comunidade (CWM). A partir de um Modelo Digital do Terreno na resolução de 1 m, foram extraídas para cada parcela a elevação, a declividade e curvatura. Os dados foram analisados por meio de correlações lineares, Análise de Coordenadas Principais (PCoA), Análises de Componente Principais (PCA) e modelo linear simples. Os resultados demonstraram correlações significativas e negativas entre Hmax x LA e Hmax x SLA. O gradiente topográfico influenciou de forma significativa a estrutura funcional do componente arbóreo. Conclui-se que a ocupação de diferentes posições no gradiente topográfico e ao longo do perfil vertical da floresta se deve ao fato das espécies apresentarem diferentes estratégias ecológicas. Palavras-chave: atributos funcionais, ecologia florestal, ecologia funcional, mata atlântica, topografia. AbstractThis study aimed to investigate functional attributes of tree species along different topographic position, in a forest located in Upper Uruguay region, in Santa Catarina. The wood density (WD), potential height (Hmax), leaf area (LA), specific leaf area (SLA), leaves renovation regime, regeneration and dispersal guilds were determined for the 20 most abundant species in the sampled area. The functional structure was evaluated through a community weight matrix (CWM) of traits values for each sampling unit. Mean values of elevation, declivity and curvature were extracted for each sampling unit, from a Terrain Digital Model in a resolution of 1 m. The data was analyzed through linear correlations, Principal Coordinates Analysis (PCoA), Principal Components Analysis (PCA) and linear simple model. The results indicated significant and negative correlation between Hmax x LA and Hmax x SLA. The topographic gradient significantly influenced the functional structure of tree component. It is concluded that the occupation of different positions along the topographic gradient and the forest vertical profile by tree species were mediated by different ecological strategies. Key words: functional attributes, forest ecology, functional structure, Atlantic forest, topography. Partição de nicho por grupos funcionais de espécies arbóreas em uma floresta subtropicalNiche partitioning by functional groups of tree species in a subtropical forest

Estruturação espacial de traços funcionais de espécies arbóreas em função da distância da borda em Floresta Alto-Montana no sul do Brasil

“…Assim, na área estudada, as espécies de maior porte, que ocupam o dossel, apresentaram maior escleromorfismo das folhas do que aquelas espécies que ocupam os estratos inferiores, o que pode ser compreendido como adaptações das espécies às diferentes condições ambientais ao longo do perfil vertical da floresta. Destaca-se que esse mesmo padrão já foi observado em outras florestas da região (SOUZA et al, 2017), o que reforça a relevância das diferenças ambientais existente entre os distintos estratos verticais de áreas com FOM como condicionante ecológico para a seleção de estratégias ecológicas.…”

Tree community dynamics in a forest adjacent to the reservoir of a hydroelectric power plant in the southern Brazilian Atlantic Forest

“…Former studies carried out in the same area also indicated floristic-structural variations in the community related to the sectors location for both the adult (Souza et al 2015) and the regenerative (Souza et al 2017a) components. By investigating the functional aspects of the area under study, Souza et al (2017b) likewise demonstrated that in the lower sector prevails a community with resources acquisition traits, however, in the slope intermediate and upper sectors conservative traits prevail. The sorting of tree species on account of the environmental gradient synthesized by relief variations is thus observed, reinforcing the importance of this ecological factor in local scale (Yang et al 2014).…”

Functional Attributes as Ecological Predictors During Secondary Succession in a Seasonal Deciduous Forest in Southern Brazil

“…When analyzing the functional attributes with the environmental variables, there was a close relationship with the local conditions of the relief and soil variables. Studies such as those by Missio et al (2016), Sousa et al (2017) and Soboleski et al (2017) have already portrayed the infl uence of environmental conditions on the coexistence of species and their functional attributes in forests in the southern region. The occurrence of more conservative species with larger leaves in higher places of the forest stretch directly refl ects the relationship of this functional attribute as an advantage in absorbing light, in contrast to species which have leaves with a smaller specifi c leaf area that invest in fast growth to capture light and less in leaf construction (Cornelissen et al, 2003).…”

“…Likewise, it is important to note that these characteristics distinguish species at diff erent succession stages which are determinants of the demographic rate and direct changes and tree composition during forest regeneration (Chazdon, 2016). The species are established according to the availability of resources and investment capacity, called conservative and acquisitive (Diaz et al, 2004;Reich, 2014), which represent this partition context of ecological niches, vertical forest structure and population distribution by environmental gradient (Sousa et al, 2017). In other words, these two considered categories refer to their acquisition and resource usage strategies, for example rapid growth (acquisitive) and slow growth (conservative).…”