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Relatório do Trabalho de Fim de Curso de Engenharia Florestal.

Descrição baseada em: Nº 4 (Jul./Ago./Set. 1988)

Climate change induces a redistribution of life on Earth that affects the effectiveness of protected areas. Species shift their ranges under climate change to track suitable climate, mainly shifting poleward and towards higher elevation. They often face degraded habitats in human-dominated landscapes and a higher extinction threat. Also, climate change may result in the loss of combinations of climatic conditions that are restricted to a given protected area. For the other hand species that have a restricted presence could expand their distribution range resulting from climate change. In order to study the effectiveness of Tejo International Nature Park, located in the center eastern part of Portugal, Maxent software was used to model the current distribution of three shrub species - Pistacia terebinthus L., Ju-niperus oxycedrus L. and Rhamnus lycioides L. - indicators of a typical Mediterranean vegetation with a regional distribution restricted to the Tejo International Natural Park, and project its future distribution considering different General Circulation Models, periods (2060 and 2080) and Representative Concentration Pathways (4.5 and 8.5). The variables most impacting on the species distribution were the mean precipitation of the driest quarter, annual precipitation, mean annual temperature, and slope. The results suggested some range expansion in the future for all three species for the studied scenarios. Those species and the vegetation where they occur will probably remain confined to center-eastern Portugal in the future, where they will continue to face relevant threats like human activity, reinforcing the need for its conservation.

Climate change induces a redistribution of life on Earth that affects the effectiveness of protected areas. Species shift their ranges under climate change to track suitable climate, mainly shifting poleward and towards higher elevation. They often face degraded habitats in human-dominated landscapes and a higher extinction threat. Also, climate change may result in the loss of combinations of climatic conditions that are restricted to a given protected area. On the other hand, species with a restricted presence could expand their distribution range resulting from climate change. To study the effectiveness of Tejo International Nature Park, located in the central-eastern part of Portugal, Maxent software was used to model the current distribution of three shrub species - Pistacia terebinthus L., Juniperus oxycedrus L. and Rhamnus lycioides L. - indicators of typical Mediterranean vegetation with a regional distribution restricted to the Tejo International Natural Park, and project its future distribution considering different General Circulation Models, periods (2060 and 2080) and Representative Concentration Pathways (4.5 and 8.5). The variables most impacting on the species distribution were the mean precipitation of the driest quarter, annual precipitation, mean annual temperature, and slope. The results suggested some range expansion in the future for all three species for the studied scenarios. Those species and the vegetation where they occur will probably remain confined to center-eastern Portugal in the future, where they will continue to face relevant threats like human activity, reinforcing the need for its conservation.

O território do Parque Natural do Tejo Internacional (PNTI) estende-se por uma área de 26484 hectares no distrito de Castelo Branco, Portugal. A vegetação do Parque é característica de ecossistemas mediterrânicos, com particular relevo para as duas séries luso-estremadurenses: Pyro bourgaeanae-Querceto rotundifoliae sigmetum e Sanguisorbo agrimonioidis-Querceto suberis sigmetum, bem como as associações préclimácicas, nomeadamente Phillyreo angustifoliae-Arbutetum unedonis, Asparago albi-Rhamnetum oleoides e Cytiso eriocarpi-Juniperetum lagunae, apresentando 726 táxones distribuídos por 98 famílias botânicas, incluindo 51 endemismos. De modo a modelar a distribuição potencial de 14 espécies lenhosas indicadoras da vegetação característica do Parque Natural do Tejo Internacional, recorreu-se ao software Maxent, com base na informação recolhida em 334 locais localizados na área do PNTI e área envolvente. Verificou-se, com base na análise realizada, que os fatores ambientais com maior influência na distribuição das espécies em estudo a precipitação anual e no quadrimestre mais seco, bem como o declive e a profundidade do solo.

Comunidades de Asphodelus bento-rainhae P. Silva : diversidade, ecologia e dinâmica serial.

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.

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.

Climate change is already a reality, and habitat loss is affecting relentlessly tree species distributions. The strawberry tree (Arbutus unedo L., Ericaceae) is a Mediterranean evergreen tree used in this article as a case study to evince its expected threatening situation in the upcoming age. This research work seeks to identify the bioclimatic and physiographic variables that have the most impact on the strawberry tree’s spatial distribution in Portugal, acquiring vital knowledge for the design of accurate conservation and afforestation plans for the use and conservation of strawberry tree, working as a guide under a climate change scenario. For that, twenty-one bioclimatic variables, two physiographic attributes (altitude and slope), and the Emberger Index (EI) were used together with 318 observations of strawberry trees, to build a scalable Bayesian procedure, based on machine learning techniques, aimed to assess the species’ future habitat evolution through three temporal scenarios: (i) Control Run (1960–1990); (ii) 2050 and (iii) 2070. The results indicate for 2050 a 30% loss of the humid subregion and a 35% increase in the semi-arid sub-region towards the north. In 2070, it is expected a 2% recuperation for the sub-humid area, but an 8% loss of the humid sub-area. Under these extreme climate change conditions, it is anticipated an almost complete loss of habitat for the strawberry tree in the south of Portugal. The expected ecological evolvability may trigger future migration paths and new refuges’ settlement in the northern sub-region for the succeeding decades and suggesting after 2070 the possibility of habitat switch and species drifting.

Increasing forest wildfires in Portugal remain a growing concern since forests in the Mediterranean region are vulnerable to recent global warming and reduction of precipitation. Therefore, a long-term negative effect is expected on the vegetation, with increasing drought and areas burnt by fires. The strawberry tree (Arbutus unedo L.) is particularly used in Portugal to produce a spirit by processing its fruits and is the main income for forestry owners. Other applications are possible due to the fruit and leaves' anti-oxidant properties and bioactive compounds production, with a potential for clinical and food uses. It is a sclerophyllous plant, dry-adapted and fire resistant, enduring the Mediterranean climate, and recently considered as a possibility for afforestation, to intensify forest discontinuity where pines and eucalypts monoculture dominate the region. To improve our knowledge about the species' spatial distribution we used 318 plots (the centroid of a 1 km2 square grid) measuring the species presence and nine environmental attributes. The seven bioclimatic variables most impacting on the species distribution and two topographic features, slope and altitude, were used. The past, current and future climate data were obtained through WorldClim. Finally, the vulnerability of the strawberry tree to the effects of global climate change was examined in the face of two emission scenarios (RCP 4.5 and 8.5), to predict distribution changes in the years 2050 and 2070, using a species distribution models (MaxEnt). The reduction of suitable habitat for this species is significant in the southern regions, considering the future scenarios of global warming. Central and northern mountainous regions are putative predicted refuges for this species. Forest policy and management should reflect the impact of climate change on the usable areas for forestry, particularly considering species adapted to the Mediterranean regions and wildfires, such as the strawberry tree. The distribution of the species in the Last Glacial Maximum (LGM) and Mid-Holocene (MH) agrees with previous genetic and paleontological studies in the region, which support putative refuges for the species. Two in the southern and coastal-central regions, since the LGM, and one in the east-central mountainous region, considered as cryptic refugia.

Growing forests wildfires in Portugal are an increasing concern since forests in the Mediterranean region are vulnerable to recent global warming. Long-term negative effects are expected on the vegetation with the coming increasing drought. The strawberry tree (Arbutus unedo L.) displays potential to be a successfully business-like cultured in several regions of Portugal and southern Europe, as it is well adapted to climate and soils. In Portugal, this species has been used by local populations particularly for spirit production and for fruit consumption, although it has different possible commercial uses, from processed and fresh fruit production to ornamental, pharmaceutical and chemical applications. In addition, due to its pioneer status, it is valuable for land recovery and desertification avoidance, besides being fire resistant. The available strawberry tree’s data is presence-only. For modelling purposes, a set of placements within the landscape of interest (Portugal) was applied. The species, observed in 318 plots, together with a vector of environmental covariates (7 bioclimatic attributes, slope and altitude) and a defined background were used for modeling purposes. Maxent 3.4.1 was the used software, where the estimated quantity is the probability of the presence of the species, conditioned on the environment. Maxent uses the environmental covariate data from the occurrence records and the background sample, to estimate the ratio between the conditional density of the covariates at the presence sites and the marginal (i.e., unconditional) density of covariates across the study area and so, estimating the relative suitability of one place vs. another. Three different climate scenarios (control run; 2050 and 2070) were tested for two emission scenarios (RCP 4.5 and RCP 8.5, WorldClim), besides the past, 6,000 BP (Mid-Holocene). The reduction of habitat suitable for this species is very significant in the southern regions, even for the best warming scenario (RCP 4.5) in 2050. Central and Northern mountain regions are predicted refuge for this species. Forest policies and management should consider the impact of climate change on the usable areas for forestry, seeing a case-study species particularly adapted to the Mediterranean regions and wildfires, such as strawberry tree. The distribution of the species in the Middle Holocene agrees with previous genetic and fossils studies in the region, which supported two putative refuges for the species since the Last Glacial Maximum and a cryptic refugia in the East-Central mountain region.

A região do Mediterrâneo sofrerá um elevado aumento de temperatura, cerca de 1,5 vezes superior ao período 1880-1920, por comparação com as outras regiões do mundo. Os impactos na floresta em Portugal, devido às alterações climáticas, sugerem uma tendência na migração de espécies, do sul para o norte e do interior para as áreas costeiras. Além disso, sob este cenário, as florestas podem desaparecer das áreas mais secas (a região interior do sul). O risco de incêndios florestais aumentará num clima mais quente e seco e pode ainda ser aumentado pela acumulação de biomassa de alta inflamabilidade no Verão. O impacto na economia florestal pode ser extremamente severo, a diminuição da produtividade, o aumento do risco de incêndio e o risco de pragas e doenças, e podem tornar o investimento florestal pouco atraente, resultando no aumento do abandono florestal. Neste estudo, o nosso objetivo foi modelar do ponto de vista ecológico uma espécie tipicamente mediterrânea amplamente distribuída no país e na região do Mediterrâneo, o medronheiro (Arbutus unedo L.). Através da modelação, é possível revelar o impacto dos fatores ambientais na distribuição dos habitats do medronheiro e avaliar a alteração do nicho ecológico usando cenários contrastantes de aquecimento global. Para aumentar o nosso conhecimento sobre a distribuição espacial da espécie, 318 pontos de presença da espécie, juntamente com um vetor de covariáveis ambientais (7 atributos bioclimáticos, declive e altitude) e pontos de não presença, foram utilizados para modelação. Os dados climáticos atuais e futuros foram obtidos através do WorldClim. Finalmente, a vulnerabilidade do medronheiro aos efeitos da mudança climática global foi examinada usando dois cenários de emissões (RCP 4.5 e 8.5), para prever mudanças de distribuição nos anos 2050 e 2070, utilizando um software de modelação ecológica (MaxEnt). A redução do habitat adequado para esta espécie é significativa nas regiões do sul, considerando os futuros cenários de aquecimento global. As regiões montanhosas do centro e do norte são presumíveis refúgios previstos para esta espécie. A política de gestão florestal deve refletir o impacto da mudança climática nas áreas utilizáveis para a silvicultura, considerando em particular as espécies adaptadas às regiões do Mediterrâneo e aos incêndios florestais, como o medronheiro.

Increasing forest wildfires in Portugal remain a growing concern since forests in the Mediterranean region are vulnerable to recent global warming and reduction of precipitation. Therefore, a long-term negative effect is expected on the vegetation, with increasing drought and areas burnt by fires. The strawberry tree (Arbutus unedo L.) is particularly used in Portugal to produce a spirit by processing its fruits and is the main income for forestry owners. Other applications are possible due to the fruit and leaves' anti-oxidant properties and bioactive compounds production, with a potential for clinical and food uses. It is a sclerophyllous plant, dry-adapted and fire resistant, enduring the Mediterranean climate, and recently considered as a possibility for afforestation, to intensify forest discontinuity where pines and eucalypts monoculture dominate the region. To improve our knowledge about the species' spatial distribution we used 318 plots (the centroid of a 1 km2 square grid) measuring the species presence and nine environmental attributes. The seven bioclimatic variables most impacting on the species distribution and two topographic features, slope and altitude, were used. The past, current and future climate data were obtained through WorldClim. Finally, the vulnerability of the strawberry tree to the effects of global climate change was examined in the face of two emission scenarios (RCP 4.5 and 8.5), to predict distribution changes in the years 2050 and 2070, using a species distribution models (MaxEnt). The reduction of suitable habitat for this species is significant in the southern regions, considering the future scenarios of global warming. Central and northern mountainous regions are putative predicted refuges for this species. Forest policy and management should reflect the impact of climate change on the usable areas for forestry, particularly considering species adapted to the Mediterranean regions and wildfires, such as the strawberry tree. The distribution of the species in the Last Glacial Maximum (LGM) and Mid-Holocene (MH) agrees with previous genetic and paleontological studies in the region, which support putative refuges for the species. Two in the southern and coastal-central regions, since the LGM, and one in the east-central mountainous region, considered as cryptic refugia.