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- Cohesión cartográfica en proyectos transfronterizos. El proyecto AguedaPublication . Sanz-Lobón, Germán; Martínez-Alegría, Roberto; Oliveira, Sandrina Fidalgo; Albuquerque, M.T.D.; Antunes, I.M.H.R.; Montequi, IsabelCohesión cartográfica en proyectos transfronterizos. El proyecto Agueda.
- Ischnura graellsii (Insecta: Odonata) a water pollution biovulnerability indicator-probability mapping using spatial uncertaintyPublication . Campos, Francisco; Velasco, T.; Sanz-Lobón, Germán; Casanueva, Patricia; Albuquerque, M.T.D.; Antunes, I.M.H.R.Ischnura graellsii (Insecta: Odonata) a water pollution biovulnerability indicator-probability mapping using spatial uncertainty.
- Bioclimatic modelling and environmental tolerance to global change in strawberry treePublication . Ribeiro, M.M.A.; Roque, Natália; Ribeiro, Sílvia; Albuquerque, M.T.D.; Gavinhos, Catarina; Quinta-Nova, L. C.The strawberry tree (Arbutus unedo L.) displays potential to be successfully businesslike-cultured in several areas of Portugal and southern Europe, but remains largely a neglected crop. This region is also particularly vulnerable to global warming, reduction of precipitations and a long-term negative effect on vegetation. To investigate interactions between the species’ distribution and ecological factors we used 319 plots (1km grid level), where the species are present in Portugal, characterized with 8 ecological attributes: ombrothermic Index (OI), thermicity Index (TI) and continentality Index (CI), pH, organic matter (OM), sand, topographic position index (TPI), number of fires (NF) and burned area (BA). The obtained matrix was firstly analyzed through PCA to reduce the space of analysis by a construction of synthesis variables (Spearman’s rank correlation matrix) and thus to detect patterns within the data set and possible collinear covariates. Finally, the vulnerability of strawberry tree to the effects of global climate change was examined. For that purpose, two ‘representative concentration pathways’ (RCPs) scenarios were predicted (RCP 2.6 and RCP 6.0) using climatic data, extracted from WorldClim, for distribution changes characterization in two periods (2050 and 2070). The MaxEnt allowed spatial Interpolation using the 319 1K plots. The PCA showed that the climatic attributes (OI, and TI) displayed the highest components’ correlation values. The strawberry tree prefers areas with higher TI and lower acidity values within the mesomediterranean and termomediterranean belts. Additionally, with lower correlation values, the presence of the species is explained by lower OI values, OM, BA and NF. The prediction results revealed reduction of the potential area of the species, providing a key tool to support conservation management decisions, to design regions of provenance, and to manage genetic improvement programs.
- Remote sensing for water quality monitoring - a case study for the Marateca reservoir, PortugalPublication . Alegria, C.M.M.; Albuquerque, M.T.D.Continuous monitoring of water resources is essential for ensuring sustainable urban water supply. Remote sensing techniques have proven to be valuable in monitoring certain qualitative parameters of water with optical characteristics. This survey was conducted in the Marateca reservoir located in central inland Portugal, after a major event that killed a considerable number of fish. The objectives of the study were as follows: (1) to define a pollution spectral signature specific to the Marateca reservoir that could shed light on the event; (2) to validate the spectral water’s quality characteristics using the data collected in five gauging points; and (3) to model the characteristics of the reservoir water, including its depth, trophic state, and turbidity. The parameters considered for analysis were total phosphorus, total nitrogen, and chlorophyll-a, which were used to calculate a trophic level index. Sentinel-2 imagery was employed to calculate spectral indices and image ratios for specific bands, aiming at the definition of spectral signatures, and to model the water characteristics in the reservoir. The trophic level index acquired from each of the five gauging points was used for validation purposes. The reservoir’s trophic level was classified as hypereutrophic and eutrophic, indicating its sensitivity to contamination. The developed methodological approach can be easily applied to other reservoirs and serves as a crucial decision-making tool for policymakers.
- Using indicator kriging for the evaluation of arsenic potential contamination in an abandoned mining area (Portugal)Publication . Antunes, I.M.H.R.; Albuquerque, M.T.D.Mining and mineral-processing activities canmodify the environment in a variety of ways. Sulfide mineralization is notorious for producing waters with high metal contents. Arsenic is commonly associated with sulfide mineralization and is considered to be toxic in the environment at low levels. The studied abandoned mining area is located in central Portugal and the resulting tailings and rejected materials were deposited and exposed to the air and water for the last 50 years. Sixteen water sample-points were collected. One of these was collected outside the mining influence, with the aim of obtaining a reference background. The risk assessment, concerning the proximity to abandoned mineralized deposits, needs the evaluation of intrinsic and specific vulnerabilities aiming the quantification of the anthropogenic activities. In this study, two indicator variables were constructed. The first one (I1), a specific vulnerability, considers the arsenic water supply standard value (0.05 mg/L), and the probability of it being exceeded is dependent on the geologic and hydrological characteristics of the studied area and also on the anthropogenic activities. The second one (I2), an intrinsic vulnerability, considers arsenic background limit as cut-off value, and depends only on the geologic and hydro-geological characteristics of the studied area. At Segura, the arsenic water content found during December 2006 (1.190 mg/L) was higher than the arsenic water content detected in October 2006 (0.636 mg/L) which could be associated to the arsenic released from Fe oxy-hydroxide. At Segura abandoned mining area, the iso-probability maps of October 2006 and December 2006, show strong anomalies associated with the water drainage from abandoned mining activities. Near the village, the probability of exceeding the arsenic background value is high but lower than the probability of exceeding the arsenic water supply value. The arsenic anomalies indicate a high probability for water arsenic contamination and those waters should not be used for human consumption.
- Modelling maritime pine (Pinus pinaster Aiton) spatial distribution and productivity in Portugal : tools for forest management.Publication . Alegria, C.M.M.; Roque, Natália; Albuquerque, M.T.D.; Fernandez, Paulo; Ribeiro, M.M.A.Research Highlights: Modelling species’ distribution and productivity is key to support integrated landscape planning, species’ afforestation, and sustainable forest management. Background and Objectives: Maritime pine (Pinus pinaster Aiton) forests in Portugal were lately affected by wildfires and measures to overcome this situation are needed. The aims of this study were: (1) to model species’ spatial distribution and productivity using a machine learning (ML) regression approach to produce current species’ distribution and productivity maps; (2) to model the species’ spatial productivity using a stochastic sequential simulation approach to produce the species’ current productivity map; (3) to produce the species’ potential distribution map, by using a ML classification approach to define species’ ecological envelope thresholds; and (4) to identify present and future key factors for the species’ afforestation and management. Materials and Methods: Spatial land cover/land use data, inventory, and environmental data (climate, topography, and soil) were used in a coupled ML regression and stochastic sequential simulation approaches to model species’ current and potential distributions and productivity. Results: Maritime pine spatial distribution modelling by the ML approach provided 69% fitting efficiency, while species productivity modelling achieved only 43%. The species’ potential area covered 60% of the country’s area, where 78% of the species’ forest inventory plots (1995) were found. The change in the Maritime pine stands’ age structure observed in the last decades is causing the species’ recovery by natural regeneration to be at risk. Conclusions: The maps produced allow for best site identification for species afforestation, wood production regulation support, landscape planning considering species’ diversity, and fire hazard mitigation. These maps were obtained by modelling using environmental covariates, such as climate attributes, so their projection in future climate change scenarios can be performed.
- Construção de cartografias de vulneraribilidadePublication . Oliveira, Sandrina Fidalgo; Albuquerque, M.T.D.; Antunes, I.M.H.R.; Seco, Maria de Fátima Magro; Roque, NatáliaA apresentação enquadra-se no âmbito do II workshop do projecto POCTEP ÁGUEDA.O projeto nasceu da necessidade de desenvolver, numa zona transfronteriça como a bacia do río Águeda, ferramentas de análise e diagnóstico ambiental para avaliação de impactes e riscos. O projeto nasceu da necessidade de desenvolver, ferramentas de análise e diagnóstico ambiental para avaliação de impactes e riscos. O ordenamento territorial sustentável permitirá planear de forma adequada todas as actividades desenvolvidas, tendo em conta os impactes e os riscos ambientais previsíveis e constituindo, desta forma, um projeto piloto para todo o eixo Luso-Espanhol. Para a sua concretização encontra-se em curso o desenvolvimento de uma plataforma metodológica de articulação territorial onde se desenvolverá uma memória descritiva que auxiliará em decisões futuras.
- A spatial statistical approach for sedimentary gold exploration: a portuguese case studyPublication . Goovaerts, Pierre; Albuquerque, M.T.D.; Antunes, I.M.H.R.This paper describes the mapping of gold content in the surroundings of abandoned gold mines located in central Portugal. In 1988, 376 samples were collected and analyzed for 22 elements. Gold (Au) was measured only inside the gold mines and its value was predicted at other locations using linear regression (R2=0.46 ) and four metals (Fe, As, Mn and W) which are known to be mostly associated with the local gold’s paragenesis. One hundred realizations of the spatial distribution of gold content were generated using sequential Gaussian simulation. Each simulated map then underwent a local cluster analysis to identify areas of significantly low or high values. The one hundred classified maps were processed to derive the most likely classification of each simulated node and the associated likelihood. The distribution of the hot-spots and cold-spots shows a clear enrichment in Au along the Erges River.
- Local versus regional soil screening levels to identify potentially polluted areasPublication . Boente, Carlos; Gerassis, Saki; Albuquerque, M.T.D.; Taboada, Javier; Gallego, J.R.Soil screening levels (SSLs) are reference threshold values required by environmental laws, established based on soil geochemical background data from often-extensive sampling areas. Such areas are often inappropriate for interpreting the true risk of pollution in small areas, since they overlook local factors (e.g., geology, industry, and traffic), which are unfeasible to encompass in large-scale samplings. To solve this issue, the calculation of local SSLs is proposed herein, performed on amajor scale closer to the area of interest. To exemplify this proposal, a soil sampling campaign was performed in the Municipality of Langreo, one of the most industrialized areas in the Principality of Asturias (northwestern Spain). Sampling allowed the measurement of local soil screening levels for several inorganic contaminants. Afterwards, a soil pollution index was calculated, referred to both regional and local thresholds, to assess the degree of contamination. Both pollution indicators were subjected to a methodology based on a Bayesian network analysis, followed by a stochastic sequential Gaussian simulation approach. The methodologies used showed differences in the identification of potentially polluted areas depending on the soil screening levels (regional or local) used. It was concluded that, in urban/industrial cores, local soil screening levels facilitate the identification of polluted areas and also reduce the uncertainty associated with sampling density and diffuse contamination. Thus, the use of local levels circumvents false-positive areas that would be classified as polluted were regional soil screening levels to be used.
- Modelação ecológica em medronheiro usando redes BaiesianasPublication . Albuquerque, M.T.D.; Gerassis, Saki; Roque, Natália; Ribeiro, Sílvia; Taboada, Javier; Martín, José; Ribeiro, M.M.A.O medronheiro (Arbutus unedo L.) tem potencial para ser uma cultura de sucesso comercial em várias regiões de Portugal, onde está bem-adaptado ao clima e solos. A espécie tem sido usada pelas populações locais para consumo do fruto em fresco ou processado, sobretudo como aguardente, no entanto continua a ser uma espécie largamente negligenciada, ainda que tenha muitos usos comerciais possíveis, desde a produção do fruto em fresco ou processado, a uso ornamental, farmacêutico, ou aplicações dos produtos bioativos. Além disso, devido ao seu estatuto pioneiro, é útil na recuperação dos solos, evitando a desertificação e tem, também, resistência ao fogo. A construção de um modelo ecológico para o medronho, foi obtida através de uma abordagem Baiesiana. Na investigação em curso, foi utilizada uma grelha de 1 Km2 ao longo de todo o território português (90425 parcelas), para o conjunto dos 10 atributos utilizados: sete variáveis bioclimáticas para a representação de uma "distância climática" - Bio1; Bio2; Bio5; Bio 9; Bio 15; Temperatura Máxima e Temperatura Mínima (WorldClim 1.4, 2017) e três variáveis geográficas - Altitude; Declive e Uso do Solo - para capturar uma "distância geográfica". Finalmente, a presença/ausência da espécie foi a variável objetivo. Foram usados quatro cenários: 1. Série de controle (1960-1990), visando a modelação das condições atuais; 2. Três diferentes cenários de efeito de estufa: Holocénico Médio (há 6000 anos); 2050 e 2070, utilizando o cenário de concentração de CO2 mais pessimista (RCP 8,5). As redes Baiesianas são Grafos Acíclicos Direcionados (GAD) onde os nós e os arcos tipificam as relações de causa e efeito entre variáveis em estudo. A estrutura topológica de um modelo Baiesiano reflete a dependência das variáveis e descreve a distribuição de probabilidade de certos acontecimentos, ocorrendo a condições específicas. As informações obtidas neste estudo serão utilizadas para a elaboração de regiões de proveniência, para melhoramento genético e conservação da espécie.