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Fenologia e ecofisiologia das macroalgas Porphyra spp. (Bangiales, Rhodophyta) e Lessonia spp. (Laminariales, Phaeophyceae) na costa norte e central do Chile: variações latitudinais e sazonais; Phenology and ecophysiology of macroalgae Porphyra spp. (Bangiales, Rhodophyta) and Lessonia spp. (Laminariales, Phaeophyceae) in north-central Chile: latitudinal and seasonal variations.

Tala, Fadia
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 05/12/2013 PT
Relevância na Pesquisa
36.23%
O propósito dos estudos fenológicos é descrever e compreender como o desenvolvimento dos organismos ocorre em resposta às variações ambientais que mudam ciclicamente e como certos fatores estimulam a geração de uma cascata de sinais e reações que abrangem desde mudanças moleculares, bioquímicas e fisiológicas, os que acabam se manifestando como padrões anuais de abundância e reprodução. As mudanças ambientais ocorrem em escalas temporais (diárias, sazonais, interanuais) e espaciais (latitudinal, em profundidade, em altitude) e têm um forte impacto no crescimento e desenvolvimento das espécies, em especial de aquelas com características sésseis. O objetivo deste estudo foi caracterizar os padrões fenológicos (sazonais e latitudinais) de abundância, reprodução, fotossíntese e capacidade antioxidante de dois gêneros de macroalgas de importância ecológica e econômica, Porphyra spp. (rodofícea) e Lessonia spp. (feofícea), distribuídas ao longo da costa norte e centro (25° - 34°S) do Chile. Os resultados mostram que variações sazonais de radiação e latitudinais de temperatura influenciam significativamente as respostas fenológicas e ecofisiológicas das espécies estudadas. No caso de Porphyra spp....

Remote phenology: Applying machine learning to detect phenological patterns in a cerrado savanna

Almeida, Jurandy; Dos Santos, Jefersson A.; Alberton, Bruna; Torres, Ricardo Da S.; Morellato, Leonor Patricia C.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Conferência ou Objeto de Conferência
ENG
Relevância na Pesquisa
36.41%
Plant phenology has gained importance in the context of global change research, stimulating the development of new technologies for phenological observation. Digital cameras have been successfully used as multi-channel imaging sensors, providing measures of leaf color change information (RGB channels), or leafing phenological changes in plants. We monitored leaf-changing patterns of a cerrado-savanna vegetation by taken daily digital images. We extract RGB channels from digital images and correlated with phenological changes. Our first goals were: (1) to test if the color change information is able to characterize the phenological pattern of a group of species; and (2) to test if individuals from the same functional group may be automatically identified using digital images. In this paper, we present a machine learning approach to detect phenological patterns in the digital images. Our preliminary results indicate that: (1) extreme hours (morning and afternoon) are the best for identifying plant species; and (2) different plant species present a different behavior with respect to the color change information. Based on those results, we suggest that individuals from the same functional group might be identified using digital images...

Applying machine learning based on multiscale classifiers to detect remote phenology patterns in Cerrado savanna trees

Almeida, Jurandy; dos Santos, Jefersson A.; Alberton, Bruna; Torres, Ricardo da S.; Morellato, Leonor Patricia C.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.35%
Plant phenology is one of the most reliable indicators of species responses to global climate change, motivating the development of new technologies for phenological monitoring. Digital cameras or near remote systems have been efficiently applied as multi-channel imaging sensors, where leaf color information is extracted from the RGB (Red, Green, and Blue) color channels, and the changes in green levels are used to infer leafing patterns of plant species. In this scenario, texture information is a great ally for image analysis that has been little used in phenology studies. We monitored leaf-changing patterns of Cerrado savanna vegetation by taking daily digital images. We extract RGB channels from the digital images and correlate them with phenological changes. Additionally, we benefit from the inclusion of textural metrics for quantifying spatial heterogeneity. Our first goals are: (1) to test if color change information is able to characterize the phenological pattern of a group of species; (2) to test if the temporal variation in image texture is useful to distinguish plant species; and (3) to test if individuals from the same species may be automatically identified using digital images. In this paper, we present a machine learning approach based on multiscale classifiers to detect phenological patterns in the digital images. Our results indicate that: (1) extreme hours (morning and afternoon) are the best for identifying plant species; (2) different plant species present a different behavior with respect to the color change information; and (3) texture variation along temporal images is promising information for capturing phenological patterns. Based on those results...

Using phenology to assess urban heat islands in tropical and temperate regions

Jochner, Susanne; Alves-Eigenheer, Milene; Menzel, Annette; Morellato, Leonor Patricia C.
Fonte: Wiley-Blackwell Publicador: Wiley-Blackwell
Tipo: Artigo de Revista Científica Formato: 3141-3151
ENG
Relevância na Pesquisa
36.39%
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Processo FAPESP: 09/54208-6; The study of urban phenology is relevant to assess the effects of heat islands and the potential impacts of climate change on plants. Temperature is the main factor regulating plant development in moist/temperate regions. However, plants in tropical cities may respond to additional environmental cues, such as air humidity. We examined whether differences in air temperature and humidity along an urban-rural gradient influenced phenological onset dates of trees in a temperate mid-latitude city (Munich, Germany) and a city in the neotropics (Campinas, Brazil). (Dis)similarities were identified incorporating equivalent study design based on identical methods for recording phenology and site-specific meteorological data. We found that phenological onset dates of silver birch (Betula pendula) were able to describe local temperature variations in Munich. Correlation coefficients between mean temperature and onset dates of Betula were significant and varied between r=-0.48 and r=-0.72. However, onset dates for yellow trumpet tree (Tabebuia chrysotricha)...

The role of phenology, growth and nutrient retention during leaf fall in the

Simões, Maria Paula; Madeira, Manuel; Gazarini, Luiz
Fonte: Universidade de Évora Publicador: Universidade de Évora
Tipo: Artigo de Revista Científica Formato: 10874 bytes; application/pdf
ENG
Relevância na Pesquisa
36.11%
Phenological patterns, growth and internal nutrient cycling of the Mediterranean shrubs Cistus salviifolius and Cistus ladanifer were analysed during 2 years of contrasted precipitation to compare their life strategies and their competitive potential to cope with future climate changes, leading to increased drought. The phenophases of both study species occurred mostly in spring, the most favourable period of the year, but while C. salviifolius produced greater number of shoot and leaves, C. ladanifer showed greater leaf area production, greater specific leaf mass and longer leaf life span. The latter species also showed more efficient N and P leaf resorption and recycling. Growth of both species was highly dependent on rainfall distribution pattern, but the two species exhibited different strategies to face the limitations imposed by the summer drought. C. salviifolius exhibited high seasonal dimorphism in plant structure, with great leaf shedding before summer drought, while the structure and biomass of C. ladanifer showed lower relative change throughout the year. The increase in length and intensity of drought also caused greater variation on growth rates and leaf duration and shedding in C. salviifolius than in C. ladanifer. Results suggest that C. ladanifer has greater stress-tolerance ability and hence higher competitive potential in response to varying environmental conditions...

A plant’s perpective of extremes: terrestrial plant responses to changing climatic variability

Reyer, Christopher; Leuzinger, Sebastian; Rammig, Anja; Bartholomeus, Ruud; Bonfante, Antonello; Lorenzi, Francesca; Dury, Marie; Gloning, Philipp; Jaoudé, Reneé; Klein, Tamir; Kuster, Thomas; Martins, Mónica; Niedrist, Georg; Riccardi, Maria; Wohlfahr
Fonte: © 2012 Blackwell Publishing Ltd, Global Change Biology, Publicador: © 2012 Blackwell Publishing Ltd, Global Change Biology,
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.11%
Abstract We review observational, experimental, and model results on how plants respond to extreme climatic conditions induced by changing climatic variability. Distinguishing between impacts of changing mean climatic conditions and changing climatic variability on terrestrial ecosystems is generally underrated in current studies. The goals of our review are thus (1) to identify plant processes that are vulnerable to changes in the variability of climatic variables rather than to changes in their mean, and (2) to depict/evaluate available study designs to quantify responses of plants to changing climatic variability. We find that phenology is largely affected by changing mean climate but also that impacts of climatic variability are much less studied, although potentially damaging. We note that plant water relations seem to be very vulnerable to extremes driven by changes in temperature and precipitation and that heatwaves and flooding have stronger impacts on physiological processes than changing mean climate. Moreover, interacting phenological and physiological processes are likely to further complicate plant responses to changing climatic variability. Phenological and physiological processes and their interactions culminate in even more sophisticated responses to changing mean climate and climatic variability at the species and community level. Generally...

Assessing the response of maize phenology under elevated temperature scenarios

Streck,Nereu Augusto; Silva,Stefanía Dalmolin da; Langner,Josana Andreia
Fonte: Sociedade Brasileira de Meteorologia Publicador: Sociedade Brasileira de Meteorologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2012 EN
Relevância na Pesquisa
36%
The objective of this study was to simulate the development of maize in elevated temperature scenarios at Santa Maria, RS, Brazil. The developmental cycle of maize was simulated with the Wang and Engel (WE) model with genotype-dependent coefficients for the cultivar BRS Missões. The developmental cycle was divided into vegetative phase (from emergence to silking), and reproductive phase (from silking to physiological maturity). Twelve sowing dates throughout the year were considered, resulting in emergences on the day 15 of each month all year round. Climate scenarios used were synthetic time series of 100 years of current climate and with increase in mean air temperature of +1, +2, +3, +4, and +5, with symmetric and asymmetric increases in daily minimum and maximum temperatures. As temperature increased, the number of years in which crop was killed by frost decreased, indicating that if global warming will confirm, the growing season for maize grown in subtropical environment will be longer by the end of this century. Maize vegetative and reproductive development was delayed or hastened depending upon the emergence time of the year, and if the increase in air temperature is symmetric or asymmetric, indicating complex Genotype x Environment interactions and high vulnerability of maize development to climate change.

Diverse responses of phenology to global changes in a grassland ecosystem

Cleland, Elsa E.; Chiariello, Nona R.; Loarie, Scott R.; Mooney, Harold A.; Field, Christopher B.
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
26.59%
Shifting plant phenology (i.e., timing of flowering and other developmental events) in recent decades establishes that species and ecosystems are already responding to global environmental change. Earlier flowering and an extended period of active plant growth across much of the northern hemisphere have been interpreted as responses to warming. However, several kinds of environmental change have the potential to influence the phenology of flowering and primary production. Here, we report shifts in phenology of flowering and canopy greenness (Normalized Difference Vegetation Index) in response to four experimentally simulated global changes: warming, elevated CO2, nitrogen (N) deposition, and increased precipitation. Consistent with previous observations, warming accelerated both flowering and greening of the canopy, but phenological responses to the other global change treatments were diverse. Elevated CO2 and N addition delayed flowering in grasses, but slightly accelerated flowering in forbs. The opposing responses of these two important functional groups decreased their phenological complementarity and potentially increased competition for limiting soil resources. At the ecosystem level, timing of canopy greenness mirrored the flowering phenology of the grasses...

Evaluating remote sensing of deciduous forest phenology at multiple spatial scales using PhenoCam imagery

Klosterman, Stephen; Hufkens, Koen; Gray, J. M.; Melaas, E.; Sonnentag, O.; Lavine, I.; Mitchell, L.; Norman, R.; Friedl, M. A.; Richardson, Andrew
Fonte: Copernicus GmbH Publicador: Copernicus GmbH
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
26.58%
Plant phenology regulates ecosystem services at local and global scales and is a sensitive indicator of global change. Estimates of phenophase transition dates, such as the start of spring or end of autumn, can be derived from sensor-based time series data at the near-surface and remote scales, but must be interpreted in terms of biologically relevant events. We use the PhenoCam archive of digital repeat photography to implement a consistent protocol for visual assessment of canopy phenology at 13 temperate deciduous forest sites throughout eastern North America, as well as to perform digital image analysis for time series-based estimates of phenology dates. We then compare these near-surface results to remote sensing metrics of phenology at the landscape scale, derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Advanced Very High Resolution Radiometer (AVHRR) sensors. We present a new type of curve fit, using a generalized sigmoid, to estimate phenology dates. We quantify the statistical uncertainty of phenophase transition dates estimated using this method and show that the generalized sigmoid results in less statistical uncertainty than other curve-fitting methods. Additionally, we find that dates derived from analysis of high-frequency PhenoCam imagery have smaller uncertainties than remote sensing metrics of phenology...

Evolutionary responses to global change: an experimental test of the effect of altered precipitation on hybridization rates in sunflower (Helianthus)

Sneck, Michelle
Fonte: Universidade Rice Publicador: Universidade Rice
ENG
Relevância na Pesquisa
36.22%
Climate change is rapidly altering natural ecosystems. Plastic and adaptive responses to climate change (i.e., range shifts and phenology) have been widely noted across taxa. However, the effects of climate change on evolutionary processes such as interspecific gene flow (hybridization) are less well known. In this study, we quantified hybridization rates in response to experimental manipulations of rainfall, an important dimension of global change. We used rain-out shelters in the field and quantified rates of hybridization between two congeners, Helianthus annuus (common sunflower) and H. petiolaris (prairie sunflower). We found that H. annuus maternal plants produced hybrid progeny more than H. petiolaris maternal plants, with a trend for decreased rates of hybridization with increased soil moisture (when rain-out shelters were absent). The relative number of open inflorescences of each species predicted hybridization rates. Thus, this study demonstrates how changing environmental conditions, specifically precipitation, could influence hybridization rates.

Dataset of Phenology of Mediterranean high-mountain meadows flora (Sierra Nevada, Spain)

P??rez-Luque, Antonio Jes??s; S??nchez-Rojas, Cristina Patricia; Zamora Rodr??guez, Regino; P??rez-P??rez, Ram??n; Bonet, Francisco Javier
Fonte: Pensoft Publicador: Pensoft
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.4%
Sierra Nevada mountain range (southern Spain) hosts a high number of endemic plant species, being one of the most important biodiversity hotspots in the Mediterranean basin. The high-mountain meadow ecosystems (borreguiles) harbour a large number of endemic and threatened plant species. In this data paper, we describe a dataset of the flora inhabiting this threatened ecosystem in this Mediterranean mountain. The dataset includes occurrence data for flora collected in those ecosystems in two periods: 1988???1990 and 2009???2013. A total of 11002 records of occurrences belonging to 19 orders, 28 families 52 genera were collected. 73 taxa were recorded with 29 threatened taxa. We also included data of cover-abundance and phenology attributes for the records. The dataset is included in the Sierra Nevada Global-Change Observatory (OBSNEV), a long-term research project designed to compile socio-ecological information on the major ecosystem types in order to identify the impacts of global change in this area.

Long-term breeding phenology shift in royal penguins

Hindell, M.; Bradshaw, C.; Brook, B.; Fordham, D.; Knowles, K.; Hull, C.; McMahon, C.
Fonte: John Wiley & Sons Ltd Publicador: John Wiley & Sons Ltd
Tipo: Artigo de Revista Científica
Publicado em //2012 EN
Relevância na Pesquisa
36.31%
The Earth's climate is undergoing rapid warming, unprecedented in recent times, which is driving shifts in the distribution and phenology of many plants and animals. Quantifying changes in breeding phenology is important for understanding how populations respond to these changes. While data on shifts in phenology are common for Northern Hemisphere species (especially birds), there is a dearth of evidence from the Southern Hemisphere, and even fewer data available from the marine environment. Surface air temperatures at Macquarie Island have increased by 0.62°C during the 30-year study period (0.21°C decade−1) and royal penguins (Eudyptes schlegeli) commenced egg laying on average three days earlier in the 1990s than during the 1960s. This contrasts with other studies of Southern Ocean seabirds; five of nine species are now breeding on average 2.1 days later than during the 1950s. Despite the different direction of these trends, they can be explained by a single underlying mechanism: resource availability. There was a negative relationship between the Southern Annular Mode (SAM) and median laying date of royal penguins, such that low-productivity (low SAM) years delayed laying date. This accords with the observations of other seabird species from the Antarctic...

Correlates and temporal variation in call phenology of eastern Ontario frogs

KLAUS, SAMANTHA P
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
Relevância na Pesquisa
36.22%
Climate change has been predicted to have long-term consequences for North American ecosystems. Amphibians in particular are considered indicators of ecosystem health because of their sensitivity to environmental change – due in part to their semi-permeable skin and aquatic developmental requirements. Amphibians have been experiencing population declines on a global scale, suggested in part to be due to changes in reproductive behaviour and timing. My thesis examines the abiotic correlates of timing of calling in southeastern Ontario anurans, as well as the extent to which the timing of calling events vary within and among species. I focused on eight species of frogs using both a 40-year historical dataset and a 5-year field-collected dataset of environmental variation and anuran activity. From analysis of the historical dataset, Lithobates pipiens was the only species out of eight to emerge significantly earlier, by an estimated 22 days over four decades. Both L. pipiens and Anaraxyus americanus have advanced initiation of calling over a four-decade span significantly earlier by an estimated 37.2 and 19.2 days, respectively, correlating with significant regional increases in spring air temperatures (2.8°C over four decades). Global frog declines or range shifts relate ultimately to changes in reproductive behaviour and timing mediated by shifting climate. From my analysis of the field-collected dataset...

Especificação e implementação do banco de dados do projeto e-phenology; Specification and implementation of the database of the e-phenology

Greice Cristina Mariano
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 09/08/2013 PT
Relevância na Pesquisa
36.51%
As mudanças ambientais tornaram-se uma questão importante na agenda global. Um exemplo representativo desses problemas surge no contexto dos estudos de fenologia. Recentemente, fenologia tem ganho importância como o indicador mais simples e confiável dos efeitos das mudanças climáticas sobre plantas e animais. A escassez ou falta de informações e sistemas de monitoramento em regiões tropicais, em particular, na América do Sul, vêm estimulando diversos centros de pesquisa a desenvolverem trabalhos visando preencher esta lacuna. Um exemplo é o Projeto e-phenology, que é multidisciplinar e combina pesquisas em Ciência da Computação e Fenologia. O principal objetivo do projeto é atacar os problemas práticos e teóricos envolvidos no uso de novas tecnologias para realizar a observação remota da fenologia de plantas e integrar estas informações com os dados de campo. Neste contexto, este trabalho apresenta a especificação e implementação de um banco de dados para gerenciar as informações que devem ser manipuladas pelo Projeto ephenology. A proposta apresentada permite a integração de dados de fenologia coletados a partir de observações no campo, com dados climáticos obtidos de sensores de clima e dados de imagens obtidas por câmeras digitais. Tanto a modelagem quanto a implementação do banco de dados tiveram como base os dados dos estudos de fenologia de plantas realizados pelos biólogos e ecólogos do grupo do Laboratório de Fenologia da UNESP de Rio Claro.; Environmental changes have become an important issue on the world. A representative example of these problems arises in context of studies of phenology. Recently...

Shifts in phenology due to global climate change: the need for a yardstick

Visser, Marcel E; Both, Christiaan
Fonte: The Royal Society Publicador: The Royal Society
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
26.46%
Climate change has led to shifts in phenology in many species distributed widely across taxonomic groups. It is, however, unclear how we should interpret these shifts without some sort of a yardstick: a measure that will reflect how much a species should be shifting to match the change in its environment caused by climate change. Here, we assume that the shift in the phenology of a species' food abundance is, by a first approximation, an appropriate yardstick. We review the few examples that are available, ranging from birds to marine plankton. In almost all of these examples, the phenology of the focal species shifts either too little (five out of 11) or too much (three out of 11) compared to the yardstick. Thus, many species are becoming mistimed due to climate change. We urge researchers with long-term datasets on phenology to link their data with those that may serve as a yardstick, because documentation of the incidence of climate change-induced mistiming is crucial in assessing the impact of global climate change on the natural world.

Global change threats to migrant shorebirds. Meeting Reports: Western Hemisphere Shorebird Group: Fifth Meeting. September 2013, Santa Marta, Colombia

D'amico, Veronica
Fonte: Wader Study Group Publicador: Wader Study Group
Tipo: info:eu-repo/semantics/article; info:ar-repo/semantics/artículo; info:eu-repo/semantics/publishedVersion Formato: application/pdf
ENG
Relevância na Pesquisa
36.09%
There is growing concern about the effects global change, natural and anthropic, on the environment and organisms. Migratory shorebirds are very sensitive to these changes being reflected at both individual and population levels. The long?distance migratory flights undertaken by shorebirds between breeding and non-breeding sites, which often exceed 14000 km, require numerous metabolic adjustments, in addition to the challenges related to the foraging activities, the competition for resources, the risk of predation, the unfavorable weather conditions and the exposure to parasites and pathogens. A successful migration implies that individuals are in optimal physical condition to enable them to meet these challenges, reach nesting sites and ensure survival. Therefore, environmental perturbations, resulted from global changes, such as loss or alteration of habitat, introduced species, pollution, contamination, and increasing human activities on the sites used by birds, can affect the condition health of individuals and the phenology of migration and breeding, threatening the survival of shorebird species. This session will highlight researches on how natural and anthropogenic factors mainly, can affect the sites used by shorebird as nesting and stopover...

Phenology feedbacks on climate change

Peñuelas, Josep; Rutishauser, This; Filella, Iolanda
Fonte: American Association for the Advancement of Science Publicador: American Association for the Advancement of Science
Tipo: Artículo Formato: 49213 bytes; application/pdf
ENG
Relevância na Pesquisa
36.11%
2 pages.-- PMID: 19443770 [PubMed].; Climate warming has advanced the biological spring and delayed the arrival of biological winter. These changes in the annual cycle of plants and the lengthening of the green-cover season have many consequences for ecological processes, agriculture, forestry, human health, and the global economy. Studies on vegetation-atmosphere interactions and particularly on the impact of leaf emergence on climate suggest that the phenological shifts in turn affect climate. The magnitude and sign of this effect are unknown but depend on water availability and regional characteristics.; Peer reviewed

GEOCLIM : a global climatology of LAI, FAPAR, and FCOVER from VEGETATION observations for 1999-2010

Verger Ten, Aleixandre; Baret, Frédéric; Weiss, Marie; Filella Cubells, Iolanda; Peñuelas, Josep
Fonte: Universidade Autônoma de Barcelona Publicador: Universidade Autônoma de Barcelona
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/acceptedVersion
Publicado em //2015 ENG
Relevância na Pesquisa
36.34%
Altres ajuts: Programes Copernicus, le Pôle Thématique Surfaces Continentales THEIA, GIOBIO (32-566) i LONGLOVE (32-594).; Land-surface modelling would benefit significantly from improved characterisation of the seasonal variability of vegetation at a global scale. GEOCLIM, a global climatology of leaf area index (LAI), fraction of absorbed photosynthetically active radiation (FAPAR)—both essential climate variables—and fraction of vegetation cover (FCOVER), is here derived from observations from the SPOT VEGETATION programme. Interannual average values from the GEOV1 Copernicus Global Land time series of biophysical products at 1-km resolution and 10-day frequency are computed for 1999 to 2010. GEOCLIM provides the baseline characteristics of the seasonal cycle of the annual vegetation phenology for each 1-km pixel on the globe. The associated standard deviation characterises the interannual variability. Temporal consistency and continuity is achieved by the accumulation of multi-year observations and the application of techniques for temporal smoothing and gap filling. Specific corrections are applied over cloudy tropical regions and high latitudes in the Northern Hemisphere where the low number of available observations compromises the reliability of estimates. Artefacts over evergreen broadleaf forests and areas of bare soil are corrected based on the expected limited seasonality. The GEOCLIM data set is demonstrated to be consistent...

Phenology, biomass and community composition changes in European shrublands submitted to experimental warming and drought

Prieto Calvo, Patricia
Fonte: Bellaterra : Universitat Autònoma de Barcelona, Publicador: Bellaterra : Universitat Autònoma de Barcelona,
Tipo: Tesis i dissertacions electròniques; info:eu-repo/semantics/doctoralThesis Formato: application/pdf
Publicado em //2008 ENG; ENG
Relevância na Pesquisa
26.51%
Descripció del recurs: el 18-08-2008; A la part superior de la portada: CREAF. Unitat d'Ecologia; Consultable des del TDX; Títol obtingut de la portada digitalitzada; Esta tesis se ha desarrollado como parte del proyecto VULCAN (Vulnerabibilty assessment of shrubland ecosystems under climatic changes), un proyecto de investigación llevado a cabo en seis ecosistemas de matorrales europeos (Gales-Reino Unido, Dinamarca, Holanda, Hungría, Cerdaña-Italia y Catalunya-España), distribuidos en un gradiente de temperatura (8.2 - 15.6 ºC) y precipitación (511 - 1427 mm). En ella se han incluido datos recogidos durante el periodo 1999-2005. El objetivo global de la investigación fue el de aportar conocimientos y reducir incertidumbres acerca del funcionamiento de los matorrales europeos y del rol que pueden desempeñar éstos como fuente o sumidero de carbono bajo la perspectiva del cambio climático. En las parcelas de los diferentes países se instalaron novedosas manipulaciones experimentales para aumentar la temperatura y para reducir el agua disponible en campo, simulando los efectos del cambio climático previstos para las décadas futuras. En este trabajo se han estudiado los efectos de los tratamientos en la diversidad vegetal...

Caracterizacion de la fenología de la vegetación a escala global mediante series temporales SPOT VEGETATION

Verger Ten, Aleixandre; Filella Cubells, Iolanda; Baret, Frédéric; Peñuelas, Josep
Fonte: Universidade Autônoma de Barcelona Publicador: Universidade Autônoma de Barcelona
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/acceptedVersion Formato: application/pdf
Publicado em //2015 SPA
Relevância na Pesquisa
46.49%
Altres ajuts: Programes Copernicus, le Pôle Thématique Surfaces Continentales THEIA, GIOBIO (32-566) i LONGLOVE (32-594).; La fenología de la vegetación a escala global se caracterizó a partir de series temporales del índice de área foliar (LAI) SPOT VEGETATION a 1-km de resolución espacial en el periodo 1999-2010. Los patrones espaciales de la fenología estimada a partir de datos de satélite muestran una gran consistencia con la distribución de biomas y factores climáticos. La comparación de la fenología SPOT VEGETATION con medidas in-situ para las fenofases del abedul común (Betula pendula) en Europa muestra un gran acuerdo en el gradiente latitudinal de temperatura con un descenso en la duración de la estación de crecimiento de 5 días por grado de latitud; We characterized the phenology of the vegetation at the global scale from the mean seasonal leaf area index (LAI) estimated from 1-km SPOT VEGETATION time series for 1999-2010. The satellite-derived phenology was spatially consistent with the global distributions of climatic drivers and biome land cover. The rate of change of phenological leaf development from VEGETATION data and in-situ observations for the date of phenophases of European birch forests agreed very well with latitudinal temperature with a decrease in the length of season of approximately five days per degree of latitude.