Efeitos de mudanças ambientais nas relações hídricas e de carbono de árvores de florestas nebulares

Orientador: Rafael Silva OliveiraTese (doutorado) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: Florestas tropicais nebulares (FTN) são um dos ecossistemas tropicais mais vulneráveis a mudanças climáticas. Esses ecossistemas possuem um grande número de espécies endêmicas que só podem sobreviver nas condições microclimáticas encontradas em FTN. Mudanças climáticas ameaçam a diversidade e funcionamento desses ecossistemas. Nessa tese eu investigo como mudanças em condições ambientais afetam as relações hídricas e o crescimento de árvores de FTN. No capítulo 1, eu investigo como absorção foliar de água (AFA) contribui para a manutenção do turgor foliar em árvores de TFN durante períodos de seca. Eu conduzi experimentos para avaliar diferenças na capacidade de AFA entre três espécies de árvores comuns em FTN. Eu também medi o efeito de exposição regular a neblina no potencial hídrico foliar de plantas expostas a seca, e usamos esses dados para modelar a resposta das espécies a secas de maior duração. Todas as espécies estudadas foram capazes de absorver água através de suas cutículas foliares e/ou tricomas, mas a taxa de AFA variou entre espécies. Durante o experimento de seca, as espécies com maior AFA mantiveram o turgor foliar por maior tempo quando expostas a neblina, enquanto espécies com menor AFA exerceram um maior controle estomático para manter o turgor foliar. Resultados do modelo ajustado aos dados do experimento de seca sugerem que, sem neblina, as espécies com maior AFA tem uma maior probabilidade de perder o turgor foliar durante secas sazonais. No capítulo 2, eu usei dois métodos de análise de dados dendrométricos distintos para medir o crescimento diário de árvores de FTN, e investigar como o crescimento de árvores com diferentes características funcionais responde a mudanças ambientais. Eu estimei o crescimento das árvores (c) diretamente de dados de mudanças de diâmetro da casca (dDb), e também com uma combinação de dDb e dados de velocidade de seiva no xilema para excluir o efeito da capacitância hidráulica da casca de dDb. Ambos os métodos usados para estimar c produziram resultados razoavelmente semelhantes em árvores de crescimento rápido (R2=0.46-0.81), mas produziram resultados bastante distintos em árvores de crescimento lento. Árvores de crescimento rápido foram capazes de crescer em um intervalo maior de condições de temperatura, radiação solar, disponibilidade de água no solo e tempo com folhas molhadas, do que espécies de crescimento lento. Entretanto, árvores de crescimento rápido também tiveram margens de segurança hidráulica menores e madeira menos densa. A maior parte das árvores aumentou seu c durante as condições mais quentes e nubladas da estação chuvosa. Nossos resultados mostram que as condições ambientais de FTN frequentemente limitam o crescimento das árvores e podem promover a perda de turgor foliar. Algumas árvores adotam estratégias hidraulicamente mais arriscadas para lidar com essas restrições ambientais, mantendo a transpiração e crescimento mesmo em condições ambientais desfavoráveis. Outras árvores adotam estratégias mais conservadoras e favorecem a manutenção de sua integridade hidráulica. Mudanças climáticas podem ameaçar particularmente árvores com alto AFA, que dependem de eventos de neblina para manutenção do turgor e crescimento durante secasAbstract: Tropical Montane Cloud Forests (TMCF) are considered one of the most vulnerable tropical ecosystems to climate change. These ecosystems possess a high number of endemic species that can only thrive on the particular environmental conditions found in TMCF. Increases in temperature and changes in the frequency of cloud immersion events might threaten the diversity and functioning of these ecosystems. In this thesis, I investigate how environmental conditions affect carbon and water relations of TMCF trees. In chapter 1, I investigated how foliar water uptake (FWU) helps TMCF trees to maintain leaf turgor during soil drought. I conducted several experiments using apoplastic tracers, deuterium labeling and leaf immersion in water to evaluate differences in FWU among three common TMCF tree species. I also measured the effect of regular fog exposure on the leaf water potential of plants subjected to soil drought and used these data to model species¿ response to long-term drought. All the studied species were able to absorb water through their leaf cuticles and/or trichomes, although the capacity to do so differed between species. During the drought experiment, the species with higher FWU capacity maintained leaf turgor for a longer period when exposed to fog, whereas the species with lower FWU exerted tighter stomatal regulation to maintain leaf turgor. The model fitted to the experimental data suggest that without fog, species with high FWU are more likely to lose turgor during seasonal droughts. In chapter 2, I used two different dendrometer techniques to measure daily growth of TMCF trees, and investigate how the growth of trees with different functional traits responds to changes in environmental conditions. I estimated tree growth (g) directly from bark diameter changes (dDb), and also using a combination of dDb and sap velocity measurements to exclude the bark capacitance effect from dDb. I measured tree functional traits such as xylem hydraulic safety margins, stomatal regulation strategies and wood density. Both methods to estimate g showed a medium to high agreement (R2=0.46-0.81) in fast-growing trees, but poor agreement in slow growing trees. Fast growing trees were able to grow in a wider range of temperature, irradiance, soil water availability and leaf-wetting conditions than slow growing trees. However, fast growing trees had narrower xylem safety margins and less dense wood. Most trees increased g during hotter and cloudy wet season conditions. These results show that environmental conditions in TMCF often limit tree growth and promote leaf turgor loss. The TMCF trees developed different strategies to deal with these environmental restrictions. Some trees adopt hydraulically riskier strategies favoring carbon uptake even during unfavorable periods; while others are more conservative and favor hydraulic safety. Climatic changes that alter fog events might threaten particularly trees with high FWU, which depend on leaf-wetting events for the maintenance of leaf turgor and growth during droughtsDoutoradoEcologiaDoutor em Ecologia2010/17204-0, 2011/52072-0, 2013/19555-2FAPESPCNPQCAPE

THEORETICAL AND METHODOLOGICAL ASPECTS OF CLOUD WATER INTERCEPTION

Cloud water interception (CWI) occurs when water contained in fog and wind-driven rain collides with vegetation, merges into larger droplets, and precipitates to the ground. CWI has an important function as an additional source of water and its relationships with tropical cloud forests have often been emphasized. Despite its importance, there is no standardization of measurement methods, nor of the terms that designate the process in Portuguese. Therefore, a systematic analysis of research on CWI is necessary. To this end, the present study carried out a review of the theoretical and methodological aspects of CWI through description and analysis of terminology; history and chronology of studies on the topic; survey of the environmental conditions necessary for the CWI process to occur; analysis of methodological aspects relating to the measurement of CWI; and synthesis and discussion of magnitudes described in scientific literature. As a result, of the 31 publications reviewed, 14 different words were found, the most common being “Cloud Water Interception” (19.4%) and “Fog Drip” (16.1%). In general, CWI is more common in places such as continental edges and islands that are constantly subject to sea breezes. In most cases, the below-canopy measurement approach can be considered more accurate than those obtained by fog collectors. CWI is on average responsible for 42% of effective precipitation (n:41). The values listed show a large variation, between 0.5% and 462%, probably due to the different environmental characteristics of the sampled locations as well as variations in sample sizes

Ecofisiologia e ecohidrologia de uma floresta tropical chuvosa e uma floresta tropical nebular

Orientador: Rafael Silva OliveiraTese (doutorado) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: A água é um dos principais fatores afetando quase todos os processos bióticos e abióticos que ocorrem na superfície do planeta. Sobre a superfície do planeta, plantas modulam fortemente a dinâmica da água. Plantas conectam o solo com a atmosfera através de suas raízes até as folhas, através do seu sistema de transporte hídrico, formando o contínuo solo-planta-atmosfera. Entretanto, temos muitas lacunas no nosso entendimento do transporte de água de plantas, desde os mecanismos atmosféricos determinando o transporte de água, disponibilidade de água no solo até a fisiologia do sistema de transporte hídrico de plantas e seus custos e demandas conflitantes. Para preencher essas lacunas, nesta tese eu uso novas abordagens para entender a demanda atmosférica de água, o transporte de água da atmosfera para o solo e os custos nutricionais do sistema de transporte de água de plantas em uma Floresta Tropical Nebular e uma Floresta Tropical Chovosa. No primeiro capítulo, eu uso um método inovador para estudar com alta resolução temporal os efeitos da neblina na água do solo e da atmosfera. No segundo capítulo, eu estudo um processo frequentemente ignorado, o transporte de água da atmosfera para o solo. No terceito capítulo, eu estudo e proponho novas perspectivas para entender os custos e as eficiências do sistema de transporte hídrico de plantas. No quarto capítulo, eu estudo os custos nutricionais da madeira e suas relações com o sistema de transporte hídrico de plantas. Por fim, eu discuto os principais resultados e suas implicações para a ecohidrologia e ecofisiologia de plantasAbstract: Water is one of the key drivers of almost all biotic and abiotic process that occurs in the surface of the planet. Over the terrestrial surface of the planet, plants modulate most of water dynamics. Plants connect water in the soil with the atmosphere throught their roots and up to the leaves passing through its water transport system, forming the soil-plant-atmosphere continuum. However we have many gaps in the understanding of plant water transport, from the understanding of the atmospheric drivers of water transport, soil water availability up to the plant water transport system physiology and its costs and tradeoffs. To adress those gaps, in this Thesis I use novel approaches to understand atmospheric water demand, water transport from the atmosphere to the soil and the nutritional costs of the water transport system of plants in a Tropical Cloud Forest and in a Tropical Rainforest. In the first chapter of this work, I use an innovative method to study with high temporal resolution fog effects on atmospheric and soil water inputs. In the second chapter, I study an often overlooked process, water flow from the atmosphere to the soil. In the third chapter, I study and propose new perspectives to understand the costs and efficiencies of a plant is water transport system. In the forth chapter, I study the nutritional cost of wood and its relations with plant is water transport system. Finally, I discuss the key results and its implications to plant ecohydrology and ecophysiologyDoutoradoEcologiaDoutor em EcologiaCAPE

Folkbotanical Knowledge in the Chacao Sub-valley, Caracas-Venezuela

Today, the conservation of biodiversity is a major international goal of policy makers and scientific researchers whose work informs policy. Increasingly, indigenous and folk knowledge of biodiversity is addressed as a significant source of insight into the ways in which ethnobotanical knowledge is not practically useful but constitutes intellectually coherent systems of knowledge. Critical analysis of biodiversity has shown that indigenous and folk ecological knowledge is gendarme to the survival of cultural identity as well as the broader biosystem and, in recent years, much attention has been drawn to the anthropogenic character of what were previously assumed to be natural features of the ecosystem. As the pressures on traditional and indigenous communities mount, the search for effective forms of documentation to support the study, conservation and transmission of indigenous knowledge is becoming increasingly urgent. This thesis explores and documents the folkecological knowledge of the people of Pedregal, an urban neighborhood in Caracas, Venezuela. It examines those domains and aspects of folkecological and folkbotanical knowledge that have persisted throughout the transformation of Pedregal from a rural hamlet to an urban neighbourhood exploring the effects of drastic social changes on the conservation and renewal of nature related systems of knowledge

Geological mapping and multiscalar fracture analysis of some Tepuisof the Gran Sabana (Venezuela) by using remote sensing techniques

The Gran Sabana Region (Venezuela) is characterized by the presence of some of the most impressive mountain in the world, called Tepuis. These unique flat-top mountains are carved in the Mataui Formation, a massive quartzitic sandstone representing the youngest deposit of the Proterozoic Roraima Group. This formation has been intruded by Proterozoic and Mesozoic Diabase dikes and sills, associated to hydrothermal alteration, which strongly affects the morphology of the Tepuis. In the first part of this work the various lithologies have been mapped using some advanced remote sensing techniques, resulting in a 1:25 000 geological map of the studied area. The study area is deformed by large amplitude folds with WNW/ESE and NNE/SSW axis. In addition, the Tepuis are affected by a network of high-angle fractures. The analysis of the fracture systems on the Auyan and Chimantà tepuis reveals the existence of four main joint sets, the most prominent of which has N 30° direction, while two sets of conjugate joints are are arranged simmetrically to the main set. These fractures are interpreted in relation to the folding event with NNE/SSW axis. Accordingly, a main compressive stress oriented NW/SE has been inferred. At the meso-scale additional fracture systems have been found analyzing a point cloud of a rock wall belonging to the Auyan Tepui. The comparison of structural data collected in the same area at the local and regional scales shows that the orientation of these groups of fracture planes does not match with the two sets found on the Auyan Tepui surface

Attracting and banning Ankari: Musical and Climate Change in the Kallawaya Region in Northern Bolivia

In the Kallawaya region in the Northern Bolivian Andes musical practices are closely related to the social, natural and spiritual environment: This is evident during the process of constructing and tuning instruments, but also during activities in the agrarian cycle, collective ritual and healing practices, as means of communication with the ancestors and, based on a Kallawaya perspective, during the critical involvement in influencing local weather events. In order to understand the complexity of climate change in the Kallawaya region beyond Western ontological principles the latter is of great importance. The Northern Bolivian Kallawaya refer to changes in climate as a complex of changes in local human-human and human-environmental relations based on a rupture of a certain morality and reciprocal relationship in an animate world in which music plays an important role. The study seeks to investigate and analyse the complex relationship between musical and climate change in different manifestations such as the construction and materiality of instruments, the musical sequence of the year and the poetics and aesthetics of qantu music. Musical and climate change are interrelated from a Kallawaya perspective. This will be discussed against the background of a global scientific perspective on climate change

Analysis of icing and snowfall in the Iberian peninsula by numericals

Tesis doctoral presentada en la Universidad Complutense de Madrid. Facultad de Ciencias Físicas, Departamento de Física de la Tierra y Astronomía I

Continental-scale patterns and climatic drivers of fruiting phenology: A quantitative Neotropical review

Changes in the life cycle of organisms (i.e. phenology) are one of the most widely used early-warning indicators of climate change, yet this remains poorly understood throughout the tropics. We exhaustively reviewed any published and unpublished study on fruiting phenology carried out at the community level in the American tropics and subtropics (latitudinal range: 26°N–26°S) to (1) provide a comprehensive overview of the current status of fruiting phenology research throughout the Neotropics; (2) unravel the climatic factors that have been widely reported as drivers of fruiting phenology; and (3) provide a preliminary assessment of the potential phenological responses of plants under future climatic scenarios. Despite the large number of phenological datasets uncovered (218), our review shows that their geographic distribution is very uneven and insufficient for the large surface of the Neotropics (~ 1 dataset per ~ 78,000 km2). Phenological research is concentrated in few areas with many studies (state of São Paulo, Brazil, and Costa Rica), whereas vast regions elsewhere entirely unstudied. Sampling effort in fruiting phenology studies was generally low: the majority of datasets targeted fewer than 100 plant species (71%), lasted 2 years or less (72%), and only 10.4% monitored > 15 individuals per species. We uncovered only 10 sites with ten or more years of phenological monitoring. The ratio of numbers of species sampled to overall estimates of plant species richness was wholly insufficient for highly diverse vegetation types such as tropical rainforests, seasonal forest and cerrado, and only slightly more robust for less diverse vegetation types, such as deserts, arid shrublands and open grassy savannas. Most plausible drivers of phenology extracted from these datasets were environmental (78.5%), whereas biotic drivers were rare (6%). Among climatic factors, rainfall was explicitly included in 73.4% of cases, followed by air temperature (19.3%). Other environmental cues such as water level (6%), solar radiation or photoperiod (3.2%), and ENSO events (1.4%) were rarely addressed. In addition, drivers were analyzed statistically in only 38% of datasets and techniques were basically correlative, with only 4.8% of studies including any consideration of the inherently autocorrelated character of phenological time series. Fruiting peaks were significantly more often reported during the rainy season both in rainforests and cerrado woodlands, which is at odds with the relatively aseasonal character of the former vegetation type. Given that climatic models predict harsh future conditions for the tropics, we urgently need to determine the magnitude of changes in plant reproductive phenology and distinguish those from cyclical oscillations. Long-term monitoring and herbarium data are therefore key for detecting these trends. Our review shows that the unevenness in geographic distribution of studies, and diversity of sampling methods, vegetation types, and research motivation hinder the emergence of clear general phenological patterns and drivers for the Neotropics. We therefore call for prioritizing research in unexplored areas, and improving the quantitative component and statistical design of reproductive phenology studies to enhance our predictions of climate change impacts on tropical plants and animals