Isabel Pôças

Isabel Pôças
ForestWISE · Collaborative Laboratory for Integrated Forest & Fire Management

PhD in Agrarian Sciences

About

51
Publications
22,263
Reads
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970
Citations
Citations since 2017
19 Research Items
768 Citations
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2017201820192020202120222023050100150
2017201820192020202120222023050100150
2017201820192020202120222023050100150
Additional affiliations
June 2018 - October 2020
Centro de Investigação em Ciências Geo-Espaciais (CICGE)
Position
  • PostDoc Position
March 2018 - August 2018
University of Porto
Position
  • Professor
May 2012 - April 2018
LEAF - Linking Landscape, Environment, Agriculture and Food, ISA, University of Lisbon
Position
  • PostDoc Position
Education
January 2006 - September 2010
University of Porto
Field of study
  • Agrarian Sciences
January 2000 - May 2003
Universidade de Trás-os-Montes e Alto Douro
Field of study
  • Conservation of Genetic Resources and Plant Breeding
October 1994 - September 1999
University of Porto
Field of study
  • Agronomy

Publications

Publications (51)
Conference Paper
Full-text available
Portugal enfrenta um problema estrutural relacionado com o desenvolvimento e a gestão das áreas rurais, agravado pelos efeitos das alterações climáticas. Os incêndios rurais são uma das consequências deste problema, representando uma séria ameaça à segurança das comunidades, à economia florestal, ao ambiente e ao desenvolvimento económico e social...
Article
Full-text available
Quantum yield of fluorescence (φF) is key to interpret remote measurements of sun-induced fluorescence (SIF), and whether the SIF signal is governed by photochemical quenching (PQ) or non-photochemical quenching (NPQ). Disentangling PQ from NPQ allows using SIF estimates in various applications in aquatic optics. However, obtaining φF is challengin...
Article
This paper focuses on predicting predawn leaf water potential through a self-learning artificial intelligence (SL-AI) algorithm, a novel spectral processing algorithm that is based on the search for covariance modes, providing a direct relationship between spectral information and plant constituents. The SL-AI algorithm was applied in a dataset con...
Article
Predawn leaf water potential (Ψpd) is widely used to assess plant water status. Also, pigments concentration work as proxy of canopy’s water status. Spectral data methods have been applied to monitor and assess crop’s biophysical variables. This work developed two models to estimate Ψpd using a hand-held spectroradiometer (400−1010 nm) to obtain ca...
Article
Full-text available
In California and other agricultural regions that are facing challenges with water scarcity, accurate estimates of crop evapotranspiration (ETc) can support agricultural entities in ongoing efforts to improve on-farm water use efficiency. Remote sensing approaches for calculating ETc can be used to support wide area mapping of crop coefficients and...
Article
In the past few decades, research has developed a multitude of strategies, methods and technologies to reduce consumptive water use on farms for adaptation to the increasing incidence of water scarcity, agricultural droughts and multi-sectoral competition for water. The adoption of these water-saving practices implies accurate quantification of cro...
Article
Full-text available
Land cover maps obtained at high spatial and temporal resolutions are necessary to support monitoring and management applications in areas with many smallholder and low-input agricultural systems, as those characteristic in Mozambique. Various regional and global land cover products based on Earth Observation data have been developed and made publi...
Article
The advances achieved during the last 30 years demonstrate the aptitude of the remote sensing-based vegetation indices (VI) for the assessment of crop evapotranspiration (ETc) and irrigation requirements in a simple, robust and operative manner. The foundation of these methodologies is the well-established relationship between the VIs and the basal...
Article
Full-text available
Hyperspectral data collected through a handheld spectroradiometer (400-1010 nm) were tested for assessing the grapevine predawn leaf water potential (ѱpd) measured by a Scholander chamber in two test sites of Douro wine region. The study was implemented in 2017, being a year with very hot and dry summer, conditions prone to severe water shortage. T...
Article
The predawn leaf water potential (ѱpd) is an eco-physiological indicator widely used for assessing vines water status and thus supporting irrigation management in several wine regions worldwide. However, the ѱpd is measured in a short time period before sunrise and the collection of a large sample of points is necessary to adequately represent a vi...
Research
Special Issue Information: Projections by FAO show that feeding a world population of 9.1 billion people in 2050 and meeting the United Nations’ Sustainable Development Goal of eradicating hunger (SDG2) would require raising overall food production by some 70% between 2005/07 and 2050. However, aggregate crop production at the world level is proje...
Data
Supporting Information for the manuscript entitled: “SegOptim – a R package for optimizing object-based image analyses of high-spatial resolution remotely-sensed data” (2019) authored by: Gonçalves, J., Pôças, I., Marcos, B., Mücher, C.A., and Honrado, J.P., International Journal of Applied Earth Observation and Geoinformation, 76: 218-230 This in...
Article
Full-text available
The dynamic effects of kaolin clay particle film application on the temperature and spectral reflectance of leaves of two autochthonous cultivars (Touriga Nacional (TN, n=32) and Touriga Franca (TF, n=24)) were studied in the Douro wine region. The study was implemented in 2017, in conditions prone to multiple environmental stresses that include ex...
Article
Full-text available
This study aimed to estimate the daily crop evapotranspiration (ETc) of soilless cut ‘Red Naomi’ roses, cultivated in a commercial glass greenhouse, using climatic and crop predictors. A multiple stepwise regression technique was applied for estimating ETc using the daily relative humidity, stem leaf area and number of leaves of the bended stems. T...
Article
Full-text available
Soil moisture (SM) at three depths (15, 25, and 30 cm), derived from the optical trapezoidal model (OPTRAM), was used for multiyear, multisite monitoring of agricultural droughts over two agricultural crops (Maize and Soybean) in southern Mozambique. The OPTRAM was implemented using satellite data from Sentinel-2 and was validated against field SM...
Article
Geographic Object-based Image Analysis (GEOBIA) is increasingly used to process high-spatial resolution imagery, with applications ranging from single species detection to habitat and land cover mapping. Image segmentation plays a key role in GEOBIA workflows, allowing to partition images into homogenous and mutually exclusive regions. Nonetheless,...
Article
Full-text available
Field spectra acquired from a handheld spectroradiometer and Sentinel-2 images spectra were used to investigate the applicability of hyperspectral and multispectral data in retrieving the maize leaf area index in low-input crop systems, with high spatial and intra-annual variability, and low yield, in southern Mozambique, during three years. Sevent...
Article
In this study, hyperspectral reflectance (HySR) data derived from a handheld spectroradiometer were used to assess the water status of three grapevine cultivars in two sub-regions of Douro wine region during two consecutive years. A large set of potential predictors derived from the HySR data were considered for modelling/predicting the predawn lea...
Article
Full-text available
Ongoing declines in biodiversity caused by global environmental changes call for adaptive conservation management, including the assessment of habitat suitability spatiotemporal dynamics potentially affecting species persistence. Remote sensing (RS) provides a wide-range of satellite-based environmental variables that can be fed into species distri...
Conference Paper
Full-text available
Spectral reflectance data have increasingly been used in the study of vegetation, including studies of crop water status and plant water stress. The reflectance data are often used in the form of spectral vegetation indices (VI), which describe biophysical parameters of interest. The rising availability of instruments with better spectral resolutio...
Article
Non-destructive, accurate, user-friendly and low-cost approaches to determining crop leaf area (LA) are a key tool in many agronomic and physiological studies, as well as in current agricultural management. Although there are models that estimate cut rose LA in the literature, they are generally designed for a specific stage of the crop cycle, usua...
Article
Full-text available
Several vegetation indices (VI) derived from handheld spectroradiometer reflectance data in the visible spectral region were tested for modelling grapevine water status estimated by the predawn leaf water potential ((pd)). The experimental trial was carried out in a vineyard in Douro wine region, Portugal. A statistical approach was used to evaluat...
Chapter
Full-text available
Resumo O uso da água em cevada, milho e olival de regadio foram estudados para representar culturas de inverno, e verão e lenhosas perenes. Para o efeito utilizou-se o modelo SIMDualKc que adota a aproximação dual para o cálculo e partição da evapotranspiração das culturas nas componentes de transpiração das culturas e evaporação do solo. O modelo...
Conference Paper
Full-text available
The on-going declines in biodiversity caused by global and local environmental changes call for improved monitoring and conservation schemes. Remote-sensing (RS) of earth surface stands at the forefront to tackle this challenge, by providing data at different spatial and temporal resolutions that can be related with a wide range of environmental va...
Article
Full-text available
A new procedure is proposed for estimating actual basal crop coefficients from vegetation indices (Kcb VI) considering a density coefficient (Kd) and a crop coefficient for bare soil. Kd is computed using the fraction of ground cover by vegetation (fc VI), which is also estimated from vegetation indices derived from remote sensing. A combined appro...
Article
Full-text available
This article proposes and illustrates a practical methodological framework to evaluate the fitness for use of spatial data sets for environmental and ecological applications, focusing on user requirements for specified application contexts. The methodology is based on the use of metadata to analyze similarity between the data characteristics and th...
Article
METRIC™ is a satellite-based surface energy balance model aimed at estimating and mapping crop evapotranspiration (ET). It has been applied to a large range of vegetation types, mostly annual crops. When applied to anisotropic woody canopies, such as olive orchards, extensions are required to algorithms for estimating the leaf area index (LAI), sur...
Article
Species distribution models (SDMs) studies suggest that, without control measures, the distribution of many alien invasive plant species (AIS) will increase under climate and land-use changes. Due to limited resources and large areas colonised by invaders, management and monitoring resources must be prioritised. Choices depend on the conservation v...
Conference Paper
The estimation of crop water requirements is conventionally based on the use of reference evapotranspiration and crop coefficients which are tabulated for a wide range of crops cultivated in standard conditions. In orchards, planting density and geometry, vegetation height and canopy architecture can be highly variable and the tabulated crop coeffi...
Conference Paper
The use of remote sensing for obtaining evapotranspiration (ET) from natural and agricultural surfaces is already widely used. For irrigated agriculture the two basic approaches are: (1) the solution of the energy balance equation, using remotely sensed surface temperatures and reflectances to estimate variables and components of this equation, and...
Conference Paper
Full-text available
The growth in data availability and in the number of users from non-spatial disciplines has increased the concern with spatial data management and spatial data quality. This reality contextualizes the need and importance of data quality management throughout the spatial data cycle related to data editing and sharing in the context of knowledge netw...
Article
Water and energy balance interactions with vegetation in mountainous terrain are influenced by topographic effects, spatial variation in vegetation type and density, and water availability. This is the case for the mountainous areas of northern Portugal, where ancestral irrigated meadows (lameiros) are a main component of a complex vegetation mosai...
Conference Paper
Full-text available
Satellite-based surface energy balance models have been successfully applied to estimate and map evapotranspiration (ET). The METRICtm model, Mapping EvapoTranspiration at high Resolution using Internalized Calibration, is one of such models. METRIC has been widely used over an extensive range of vegetation types and applications, mostly focusing a...
Article
Permanent semi-natural grassland meadows (lameiros) are characteristic of the mountain rural landscapes in northeast Portugal and represent the main fodder resource for livestock production. Furthermore, these meadows are recognized for their environmental, historical, cultural and visual landscape value. A monitoring study based on remote-sensing...
Conference Paper
Full-text available
Vegetation Indices derived from Earth Observation Satellite data have been broadly used for a wide range of ecological applications. One of such applications is vegetation monitoring. Properties of NDVI time series can be summarized in several metrics of the NDVI annual curve, including metrics that measure attributes related with primary productio...
Article
Landscape metrics were used to analyze landscape changes and related driving forces in a mountain rural landscape of Northeast Portugal over three decades. This landscape has great heterogeneity, which favors high levels of diversity and provides for a variety of habitats. The landscape metrics were obtained from land cover maps derived from Landsa...
Article
Image data from Earth Observation Satellites (EOS) were used to analyse mountain landscape changes in Northeast Portugal. Three Landsat images, from April 30th 1979, March 14th 1989 and May 29th 2002 were used. A supervised classification was performed for each image based on the radiometric information and the Normalised Difference Vegetation Inde...
Conference Paper
The sustainable conservation of mountain semi-natural meadows depends on the knowledge of their vegetation dynamics and management practices. Time series of vegetation indices (VI) derived from high temporal resolution satellite images can be a useful tool to the sustainable management of semi-natural meadows ecosystem and grazing activities. In th...
Article
The main purpose of this work is to evaluate the most appropriate Vegetation Indices (VI) from MODIS (250 m resolution), to identify and assess the growth pattern of semi-natural meadows in northern Portugal. Sixteen-day MODIS-TERRA (250x250m) composites from 2001 to 2008 were used to examine the annual temporal profile of the NDVI and EVI, and the...
Article
Full-text available
Lameiros" are ancestral semi-natural meadows, essential elements of mountain landscapes in Northern Portugal. In the "lameiros" a traditional irrigation system is used and water is applied all year around. They are mainly used for forage production for autochthonous bovine feeding, but they are also important for the water and nutrients cycle regul...
Conference Paper
Full-text available
Resumo Funcho (Foeniculum vulgare Mill.) é da família das Umbelíferas (Apiaceae) sendo uma espécie aromática típica do Mediterrâneo, designadamente na Península Ibérica. Esta espécie é utilizada desde a antiguidade para distintos fins, nomeadamente medicinal e culinário. Com este trabalho pretende-se apresentar a espécie em termos taxonomicos e eco...
Conference Paper
Full-text available
Abstract Title: Fennel (Foeniculum vulgare Mill.) - Morphological characterization of wild populations from Entre Douro e Minho. Fennel (Foeniculum vulgare Mill.) is an Umbelíferae (Apiaceae) species. This aromatic plant is characteristic from the Mediterranean, in special Peninsula Iberian, and is utilised from Antiquity as medicinal and as condim...
Article
Resumo Os lameiros são pastagens seminaturais permanentes, de origem centenária, profundamente interligados com os diversos agro-sistemas que caracterizam a agricultura tradicional de montanha. Localizados preferencialmente em zonas com elevadas disponibilidades hídricas e solos férteis e normalmente a cotas superiores aos 700m, os lameiros distrib...

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Cited By

Projects

Projects (5)
Project
To devise an early-warning system for Montesinho natural park (Portugal), where species’ conservation status is estimated by spatio-temporal trends in species’ habitat suitability index from ecological niche models.
Project
Project coordinator: University of Banja Luka, Bosnia-Herzegovina Portuguese partner: Instituto Superior de Agronomia, LEAF, University of Lisbon The main objectives of SMARTWATER are: 1) to reinforce the networking, research and innovation capacities of the University of Banja Luka (UNI-BL) and other institutions from Bosnia and Herzegovina in the field of sustainable agricultural water management; and 2) to increase their competences and fund-rising skills for a successful participation in the EU Research and Innovation Programs. The project will develop a large set of joint activities promoting networking, joint experimental fields, research cooperation and the exchange of knowledge and experts on specific topics, which are complementary and compatible with the overall national research strategy and include the application of smart technologies (cloud-based and remote sensing) in agricultural water management, optimization of water-energy-food nexus and climate change impact and adaptation measures. SMARTWATER foresees the publication of joint research documents in international conferences and peer reviewed journals. The project will provide technical assistance and expertise to improve the research and innovation capacities of BH institutions and to delineate adequate national research strategies and policies for the future. The project will boost the S&T capacity through a series of capacity building actions focusing mainly on the early stage researchers. These include advanced training courses, participation in a joint MSc program, summer schools and hands-on workshops on R&I funding. A modern scientific strategy for stepping up and stimulating scientific excellence and innovation capacity will be outlined following a multi-stakeholder participatory approach. An effective communication and dissemination strategy for the adequate promotion of twinning activities and ensuring the expected impacts at regional, national, EU and global level will be adopted. The activities will be carried out in collaboration with three reputed EU international research partners (CIHEAM-IAMB, CSIC and ISA), and a SME.
Project
The Square Kilometer Array (SKA) will be the first transcontinental radio telescope ever created. It will add 3,000 parabolic antennas and one million dipole antennas. Mid-frequency antennas will be able to increase the rate of celestial observation in ten thousand times, with a sensitivity 50 times superior. The impact of the scientific infrastructures of SKA on biodiversity and the synergies with agricultural practices will be assessed.