. 2008. Estimation of biomass and carbon stocks: the case of the Atlantic Forest. Biota Neotrop. 8(2): http://www.biotaneotropica.org.br/v8n2/en/abstract?point-ofview+bn00108022008. Abstract:The main objective of this paper is to present and discuss the best methods to estimate live above ground biomass in the Atlantic Forest. The methods presented and conclusions are the products of a workshop entitled "Estimation of Biomass and Carbon Stocks: the Case of Atlantic Rain Forest". Aboveground biomass (AGB) in tropical forests is mainly contained in trees. Tree biomass is a function of wood volume, obtained from the diameter and height, architecture and wood density (dry weight per unit volume of fresh wood). It can be quantified by the direct (destructive) or indirect method where the biomass quantification is estimated using mathematical models. The allometric model can be site specific when elaborated to a particular ecosystem or general that can be used in different sites. For the Atlantic Forest, despite the importance of it, there are only two direct measurements of tree biomass, resulting in allometric models specific for this ecosystem. To select one or other of the available models in the literature to estimate AGB it is necessary take into account what is the main question to be answered and the ease with which it is possible to measure the independent variables in the model. Models that present more accurate estimates should be preferred. However, more simple models (those with one independent variable, usually DBH) can be used when the focus is monitoring the variation in carbon storage through the time. Our observations in the Atlantic Forest suggest that pan-tropical relations proposed by Chave et al. (2005) can be confidently used to estimated tree biomass across biomes as long as tree diameter (DBH), height, and wood density are accounted for in the model. Resumo: O principal objetivo deste artigo é apresentar e discutir a melhor forma para estimar a biomassa viva acima do solo (BVS) na Mata Atlântica. A biomassa viva acima do solo em florestas tropicais esta contida principalmente nas árvores. A biomassa das árvores é uma função do seu volume de madeira, obtido do diâmetro e da altura, de sua arquitetura e da densidade de sua madeira (peso seco por unidade de volume fresco). Ela pode ser quantificada pelo método direto (destrutivo) ou pelo método indireto onde a quantificação da biomassa é feita através de modelos matemáticos. Os modelos alométricos podem ser específicos para um determinado local, quando elaborado para um ecossistema particular, ou gerais, que podem ser utilizados em para estimar a biomassa em diferentes locais. Para a Mata Atlântica, a despeito de sua importância, existem somente duas medidas diretas de biomassa de árvores, que resultaram em modelos alométricos específicos para essas florestas. Para selecionar um ou outro modelo alométrico para estimar BVS, disponível na literatura, é necessário levar em conta o a questão a ser respondida e a facilidade com a qual é possível medir...

Traditionally, trait‐based studies have explored single‐trait‐fitness relationships. However, this approximation in the study of fitness components is often too simplistic, given that fitness is determined by the interplay of multiple traits, which could even lead to multiple functional strategies with comparable fitness (i.e. alternative designs). Here we suggest that an analytical framework using boosted regression trees (BRT) can prove more informative to test hypotheses on trait combinations compared to standard linear models. We use two published datasets for comparisons: a botanical garden dataset with 557 plant species (Herben, 2012, Journal of Ecology, 100, 1522) and an observational dataset with 83 plant species (Adler, 2014, Proceedings of the National Academy of Sciences, 111, 740). Using the observational dataset, we found that BRTs predict the role of traits on the relative importance of survival, growth and reproduction for population growth rate better than linear models do. Moreover, we split species cultivated in different habitats within the botanical garden and observed that seed and vegetative reproduction depended on trait combinations in most habitats. Our analyses suggest that, while not all traits impact fitness components to the same degree, it is crucial to consider traits that represent different ecological dimensions. Synthesis. The analysis of trait combinations, and corresponding alternative designs via BRTs, represent a promising approach for understanding and managing functional changes in vegetation composition through measurement of suites of relatively easily measurable traits.

Striking progress has been made on conceptual and methodological aspects linking species traits to community and ecosystem responses to environmental change. However, the first step when using a trait-based approach (i.e., choosing the adequate traits reflecting species response to a given environmental driver) deserves much more attention. The first broad comparative studies, using worldwide datasets, have identified a number of traits that are, for example, good indicators of plant responses to water and nutrient availability, or good indicators of plant species defense against herbivory and plant effects on litter decomposition. Due to the successful explanation of global patterns of trait variation and the relatively easy measurements, some functional traits have become widely used. However, it is starting to be questioned whether the status of such "fashionable traits" is always justified; especially considering that particular traits might be the result of underlying traits that respond to distinct environmental factors. Some global trade-offs between traits reflecting contrasting resource use strategies do not hold under changing environmental conditions. Therefore, the choice of traits to up-scale responses of individuals to communities and ecosystems should be based on their adequacy for a specified ecological context. Here, we present a framework that helps identifying objective criteria for the choice of functional traits for studies on community assembly and ecosystem processes and services. This framework comprises five steps: 1) identification of the main environmental drivers; 2) identification of the relevant physiological processes allowing species to cope with the environment; 3) selection of traits that are involved in such physiological processes; 4) validation of the select traits at community level and; 5) evaluation of possible consequences for ecosystem processes/services.

Question: Although the restinga vegetation lies adjacent to the species-rich Atlantic Rainforest, fewer species thrive due to low available resources of the sandy substrate. We asked whether there is a specific set of functional traits related to the ability to attain high dominance in a restinga dominated by a CAM photosynthesis tree. Location: Restinga of Jurubatiba National Park, north of the state of Rio de Janeiro, Brazil. Methods: We chose traits that are commonly used in large screenings, leaf mass per area (LMA), leaf longevity (LL) and leaf nitrogen concentration (LNC). We also measured the functional traits, midday leaf water potential (C min ), pressure-volume curves, nitrogen isotope discrimination (d 15 N) and chlorophyll fluorescence. We compared species using ANOVA and ordination analysis. Results: The two most dominant species differed from subordinate species in terms of leaf succulence (SUC) and C min . However, they were also significantly different from each other in LMA, SUC, leaf thickness and LNC. C min and d 15 N had the strongest loadings on the third ordination axis, which, despite explaining only 18.2% of total variance, was the only axis reflecting variation in species dominance. Conclusions: Despite high interspecific variation, the most common traits of the leaf economic spectrum were not directly associated with variation in species dominance. In contrast, the bulk modulus of elasticity, C min and d 15 N were important not only to track the connection between plant traits and environmental factors, but also between plant traits and community structure.

AbstractmChlorophyll a fluorescence parameters showing the instantaneous performance and carbon-isotope ratios reflecting long-term behaviour of leaves were determined for a large number of mistletoe/host-pairs in the cerrado belt of Brazil. Study sites were a very exposed rupestrian field, a semi-exposed savanna and a highly shaded gallery forest. The major question asked was if photosynthetic capacity of mistletoe leaves differed from that of the leaves of their respective hosts. It is shown that except for the very exposed rupestrian field site, photosynthetic capacity appeared to be similar in mistletoes and host leaves. The superior behaviour of host leaves in the rupestrian field was due to particularly expressed sun-plant characteristics of the host. However, mistletoes always had higher average sto-matal conductances, lower leaf temperatures at similar or even higher irradiance and higher intercellular CO2-partial pressures than hosts. Photosynthetic performance of mistletoe leaves was independent of whether a given mistletoe species parasitized aluminium-accumulating or non-accumulating host species in the cerrados with their aluminiumrich soils.