Search results

Contém referências bibliográficas

Relatório do Trabalho de Fim de Curso em Engenharia Florestal apresentado à Escola Superior Agrária do Instituto Politécnico de Castelo Branco, do qual só está disponível o resumo.

Bibliografia : p. 49

Disponível na Biblioteca da ESACB na cota C30-15799TFCPF.

Straddling the frontiers of two neighbouring countries around the Tagus River, Portugal and Spain, the International Tagus River Natural Park (ITRNP) extends over an area of 26,484 hectares in the district of Castelo Branco, Portugal. The vegetation of the Park is mainly typical of Mediterranean ecosystems, such as cork oak and holm oak, Mediterranean evergreen scrubland with strawberry tree, kerms oak, terebinth, mock privet, and mastic; thermophilic formations of rockrose, lavender and broom; bush formations, more or less open with olive and wild olive trees; and riparian vegetation, emphasizing the bushweed formations and the galleries of willow trees. In this territory, 726 taxa distributed by 98 botanical families have been identified to date, emphasizing the 51 endemic species detected. In terms of protected Flora the ITRNP the Portuguese endemisms Festuca duriotagana and Linaria amethystea subsp. multipunctata. There are also 41 Iberian endemisms. A study was conducted in the ITRNP to provide insight into the main factors affecting the different plant communities’ distribution in the region, and to provide recommendations for the selection of indigenous species in order to monitor the succession process of vegetation in areas affected by wildfires. The study was conducted in sites evenly distributed in the area of ITRNP representing homogeneous vegetation types, the floristic composition and cover of the species were determined in 188 floristic inventories. During the study period, a total of 249 species were recorded. Cluster analysis identified 12 main vegetation communities. The sites were ecologically characterized, at a local scale, using environmental data as bioclimatology, lithology, topography, soil type and its physical and chemical composition. The role of those environmental factors in the explanation of vegetation variation was assessed using canonical correspondence analysis (CCA). Geostatistics tools were also used to interpolate the species distribution and the community diversity index.

Straddling the frontiers of two neighboring countries around the Tagus River, Portugal and Spain, the International Tagus River Natural Park (ITRNP) extends over an area of 26,484 hectares in the district of Castelo Branco, Portugal. The vegetation of the Park is mainly typical of Mediterranean ecosystems, such as cork oak and holm oak, Mediterranean evergreen scrubland with strawberry tree, kerms oak, terebinth, mock privet, and mastic; thermophilic formations of rockrose, lavender and broom; bush formations, more or less open with olive and wild olive trees; and riparian vegetation, emphasizing the bushweed formations and the galleries of willow trees. In this territory, 726 taxa distributed by 98 botanical families have been identified to date, emphasizing the 51 endemic species detected. In terms of protected Flora the ITRNP the Portuguese endemisms Festuca duriotagana and Linaria amethystea subsp. multipunctata. There are also 41 Iberian endemisms. A study was conducted in the ITRNP to provide insight into the main factors affecting the different plant communities’ distribution in the region, and to provide recommendations for the selection of indigenous species in order to monitor the succession process of vegetation in areas affected by wildfires. The study was conducted in sites evenly distributed in the area of ITRNP representing homogeneous vegetation types, the floristic composition and cover of the species were determined in 188 floristic inventories. During the study period, a total of 249 species were recorded. Cluster analysis identified 12 main vegetation communities. The sites were ecologically characterized, at a local scale, using environmental data as bioclimatology, lithology, topography, soil type and its physical and chemical composition. The role of those environmental factors in the explanation of vegetation variation was assessed using canonical correspondence analysis (CCA). Geostatistics tools were also used to interpolate the species distribution and the community diversity index.

O PNTI estende-se por uma área de 26484 hectares no distrito de Castelo Branco, Portugal. A vegetação do Parque é característica de ecossistemas mediterrânicos, apresentando 726 táxones distribuídos por 98 famílias botânicas, incluindo 51 endemismos. O estudo pretendeu identificar a influência da utilização agrícola, pecuária e florestal do território na distribuição das espécies vegetais e na diversidade das comunidades vegetais com valor para conservação. Com base na realização de 188 inventários florísticos foi determinada a composição florística e a respetiva abundância, identificando-se um total de 249 táxones. Os locais dos inventários foram caracterizados em termos edafoclimáticos, recorrendo-se às métricas da paisagem para caracterizar a estrutura de uso. A influência dos fatores ambientais na distribuição espacial das espécies vegetais foi avaliado através da análise canónica de correspondências. Relacionaram-se, ainda, as métricas da paisagem com os valores de diversidade florística com recurso à regressão linear.

Esta linha de investigação assenta nos princípios da Macroecologia que é um ramo da Ecologia e Biogeografia. Procura ter uma visão global de um território abrangendo um conjunto de comunidades a várias escalas e de uma forma integrada, para a caracterizar como um todo. Esta disciplina científica procura identificar padrões na distribuição, abundância e riqueza das espécies. Inclui o desenvolvimento de modelos que expliquem estes padrões. Para tal, recorre a um conjunto de ferramentas de análise dos parâmetros ambientais e biológicos. Para o efeito recorre-se a várias ferramentas metodológicas, designadamente: modelação ecológica, geoestatística ambiental, estatística multivariada e análise espacial com recurso a Sistemas de Informação Geográfica. A escala da paisagem está frequentemente presente na conceptualização de serviços de ecossistema. Determinadas funções e processos responsáveis pela oferta de serviços particulares são apenas concebíveis considerando uma escala espacial mais ampla (e.g, biodiversidade, conservação do solo, hidrologia). A classificação dos serviços tem como papel facilitar a valorização e monitorização dos ecossistemas com base na discretização das suas funções e processos particulares que são responsáveis pela oferta de bens ou serviços. Neste âmbito como avaliar a influência de diferentes práticas agroflorestais na biodiversidade? Esta é uma das questões prioritárias que o país deverá responder no quadro dos processos políticos internacionais em que está envolvido. Pretende-se, deste modo, avaliar um dos serviços de suporte - a Biodiversidade, associado aos modelos de exploração agrícola e florestal, ao nível da paisagem e das unidades de gestão através de uma abordagem centrada numa rede de amostragem estratificada. Este método será sistematicamente aplicado para testar a capacidade de avaliação do sistema. Como forma de poder avaliar esta problemática também a um nível mais direcionado, propõe-se a abordagem como “case study” do comportamento do medronheiro (Arbutus unedo L.), espécie de grande relevância na flora espontânea autóctone de Portugal, mas também como espécie piloto em processos de modelação bioclimática face a alterações de clima. Para isso deverão ser usados os pontos do inventário florestal (2006) que são cerca de 80, e nos dão a presença da espécie nesses locais, usando essa malha para fazer modelação, usando os dados de distribuição da espécie (os 80 pontos), os dados ambientais através da informação digital (topografia, solos, clima, etc) e algoritmos para relacionar a distribuição da espécie com as variáveis ambientais. A validação do modelo poderá ser feita utilizando os dados de 15 povoamentos já estudados sendo o MAXENT um dos algoritmos possíveis. Este estudo permitirá fazer a projeção da distribuição da espécie em cenários de alteração climática, por extrapolação. Para completar este processo serão trabalhados dados genéticos, que permitirão associar o comportamento ecológico da espécie às características genéticas dos possíveis ecótipos.

In recent years there has been an increase of investment in so called emerging fruit crops. It is agreed that the choice of uses and practices best suited to soil and climate conditions promotes the sustainable use of rural areas, with positive economic impacts. The objective of this study is to determine the suitability of emerging fruit crops based on the analysis of the limiting factors. The suitability was examined for the present time and in the face of two future emission scenarios (RCP 4.5 and 8.5). For this purpose, the biophysical criteria determining the cultivation of pistachio tree, strawberry tree and almond tree were processed using ArcGIS 10.8. The Analytical Hierarchy Process (AHP) was used to determine suitability for the crops. A pairwise comparison between environmental criteria (temperature, rainfall, chilling hours, crop heat units, relative humidity, topography, and soil proprieties) was performed to calculate the weights of these criteria. As a result of the AHP suitability maps for each crop in the present conditions, for the RCP 4.5 and the RCP 8.5 scenarios were produced. In the present conditions about 16.4% of the study area is classified as highly suitable for almond tree, 15.8% to strawberry tree, and 15.9% to pistachio tree. For the future scenarios, the area with high suitability will increase for almond tree and pistachio tree and will decrease for strawberry tree. It is the essential to be aware of the suitability and resilience of new crops to meet the need to adapt to climate change.

Obligate coastline taxa generally occupy very limited areas, especially when there is a close affinity with a specific coast type. Climate change can be a meaningful threat for them, reducing suitable habitat or forcing migration events. Cistus ladanifer subsp. sulcatus is an endemic plant of Portugal, known to occur only in the top of its south-western coast’s prominent cliffs. In spite of being included in the annexes II and IV of the European Habitats Directive of Natura 2000 Network, this taxon is still understudied, especially regarding the effects of climate change on its distribution. To overcome such gap, Maxent was used to model the current distribution of C. ladanifer subsp. sulcatus and project its future distribution considering different General Circulation Models, periods (2050 and 2070) and Representation Concentration Pathways (4.5 and 8.5). The results suggested an extensive range contraction in the future, and extinction is a possible scenario. The proximity to littoral cliffs is crucial for this plant’s occurrence, but these formations are irregularly distributed along the coast, hindering range expansions, further inhibited by a small dispersal capacity. Cistus ladanifer subsp. sulcatus will probably remain confined to south-western Portugal in the future, where it will continue to face relevant threats like human activity, reinforcing the need for its conservation.

To date, a variety of species potential distribution mapping approaches have been used, and the agreement in maps produced with different methodological approaches should be assessed. The aims of this study were: (1) to model Maritime pine potential distributions for the present and for the future under two climate change scenarios using the machine learning Maximum Entropy algorithm (MaxEnt); (2) to update the species ecological envelope maps using the same environmental data set and climate change scenarios; and (3) to perform an agreement analysis for the species distribution maps produced with both methodological approaches. The species distribution maps produced by each of the methodological approaches under study were reclassified into presence– absence binary maps of species to perform the agreement analysis. The results showed that the MaxEnt-predicted map for the present matched well the species’ current distribution, but the species ecological envelope map, also for the present, was closer to the species’ empiric potential distribution. Climate change impacts on the species’ future distributions maps using the MaxEnt were moderate, but areas were relocated. The 47.3% suitability area (regular-medium-high), in the present, increased in future climate change scenarios to 48.7%–48.3%. Conversely, the impacts in species ecological envelopes maps were higher and with greater future losses than the latter. The 76.5% suitability area (regular-favourable-optimum), in the present, decreased in future climate change scenarios to 58.2%–51.6%. The two approaches combination resulted in a 44% concordance for the species occupancy in the present, decreasing around 30%–35% in the future under the climate change scenarios. Both methodologies proved to be complementary to set species’ best suitability areas, which are key as support decision tools for planning afforestation and forest management to attain fire-resilient landscapes, enhanced forest ecosystems biodiversity, functionality and productivity.

Climate change’s huge impact on Mediterranean species’ habitat suitability and spatial and temporal distribution in the coming decades is expected. The present work aimed to reconstruct rockrose (Cistus ladanifer L.) historical and future spatial distribution, a typically Mediterranean species with abundant occurrence in North Africa, Iberian Peninsula, and Southern France. The R ensemble modeling approach was made using the biomod2 package to assess changes in the spatial distribution of the species in the Last Interglacial (LIG), the Last Glacial Maximum (LGM), and the Middle Holocene (MH), in the present, and in the future (for the years 2050 and 2070), considering two Representative Concentration Pathways (RCP 4.5 and RCP 8.5). The current species potential distribution was modeled using 2,833 occurrences, six bioclimatic variables, and four algorithms, Generalized Linear Model (GLM), MaxEnt, Multivariate Adaptive Regression Splines (MARS), and Artificial Neural Networks (ANN). Two global climate models (GCMs), CCSM4 and MRI-CGCM3, were used to forecast past and future suitability. The potential area of occurrence of the species is equal to 15.8 and 14.1% of the study area for current and LIG conditions, while it decreased to 3.8% in the LGM. The species’ presence diaminished more than half in the RCP 4.5 (to 6.8% in 2050 and 7% in 2070), and a too low figure (2.2%) in the worst-case scenario (RCP 8.5) for 2070. The results suggested that the current climatic conditions are the most suitable for the species’ occurrence and that future changes in environmental conditions may lead to the loss of suitable habitats, especially in the worst-case scenario. The information unfolded by this study will help to understand future predictable desertification in the Mediterranean region and to help policymakers to implement possible measures for biodiversity maintenance and desertification avoidance.

Climate change is a challenge for forests in the coming decades, with a major impact on species adaptation and distribution. The Mediterranean Basin is one of the most vulnerable hotspots for biodiversity conservation under climate change in the world. This research aimed at studying a Mediterranean species well adapted to the region: the Arbutus unedo L. (strawberry tree). The MaxEnt, a presence-only species-distribution software, was used to model A. unedo’s environmental suitability. The current species potential distribution was accessed based on actual occurrences and selected environmental variables and subsequently projected for the Last Glacial Maximum (LGM), the Mid-Holocene (MH), and the years 2050 and 2070, considering the two Representative Concentration Pathways: RCP4.5 and RCP8.5. Results from the LGM projection suggest the presence of refugia in the core of the Mediterranean Basin, in particular the Iberian Peninsula (IP). The projections for the MH indicate increasing climatic suitability for the species and an eastward expansion, relatively to LGM. The predicted future environmental changes will most likely act as a catalyst for suitable habitat loss and a range shift towards the North is likely to occur.