Cartografia de risco de erosão, à escala de encosta, numa área recentemente ardida na região Centro

Mestrado em Engenharia do AmbienteEsta dissertação tem como objectivo principal a obtenção de um mapa em Sistemas de Informação Geográfica (SIG) com o programa ArcGIS, que descreve o Risco de Erosão numa área sujeita a um incêndio florestal na pequena localidade de Açores. Para cartografar o risco de erosão do solo foram seleccionados dois modelos. A Equação Universal de Perdas de Solo (Universal Soil Loss Equation – USLE) pelo facto de ter sido escolhida pelo INAG na elaboração do mapa “Perdas de Solo após incêndios Florestais do Verão de 2003” e o modelo Morgan–Morgan–Finney (MMF) pelo facto de apresentar um elevado potencial na determinação de perdas de solo em áreas ardidas. Devido ao facto de ambos os modelos terem sido desenvolvidos especificamente para áreas agrícolas, pretende-se, neste estudo, avaliar a adequação dos seus resultados para uma área florestal recentemente ardida. Para avaliar os dois modelos, os seus resultados foram comparados com dados anteriormente recolhidos pelo projecto EROSFIRE através de Simulações de Chuva e de Parcelas Abertas, e ainda no âmbito deste trabalho através de uma validação de campo que consistiu numa inventariação de fenómenos erosivos no local. Tal como era esperado, observam-se falhas na determinação das taxas de erosão segundo os dois modelos e tal facto é justificado por ambos dependerem de factores empíricos que dizem respeito ao coberto vegetal e às práticas de conservação de solo utilizadas (Factor C e P). ABSTRACT: The main objective of this thesis is to obtain a Geographic Information System map that describes the Erosion Hazard in an area on the little village of Açores after a forest fire. To follow up this proposed aim, two referenced erosion models where selected. The Universal Soil Equation (USLE) because was chosen by INAG to built the map “Soil losses after forest fires in 2003 summer” and the Morgan-Morgan-Finney model (MMF) because presents a high potential in determination of soil losses in bunt areas. Due to the fact that both models were develop specifically to be applied in agricultural land fields, it is a purpose in this study to evaluate the relation of its results in a recent burnt area. Through Rainfall Simulation and Open Plot data that was collected by the EROSFIRE project in 2005/2006 year, and also with a Field Validation based on a survey for erosion features that was made in this study, the difference between the reality and the applied models will be exposed. As is was expected, the detected weakness of the obtained erosion risk models results is justified due to, both models depend on empirical factors (C and P) that correspond to cover and management and support practice factor respectably

Estudo e modelação dos processos hidrológicos e erosivos em bacias hidrográficas ardidas

Doutoramento em Ciências e Engenharia do AmbienteForest fires implications in overland flow and soil erosion have been researched for several years. Therefore, is widely known that fires enhance hydrological and geomorphological activity worldwide as also in Mediterranean areas. Soil burn severity has been widely used to describe the impacts of fire on soils, and has being recognized as a decisive factor controlling post-fire erosion rates. However, there is no unique definition of the term and the relationship between soil burn severity and post-fire hydrological and erosion response has not yet been fully established. Few studies have assessed post-fire erosion over multiple years, and the authors are aware of none which assess runoff. Small amount of studies concerning pre-fire management practices were also found. In the case of soil erosion models, the Revised Universal Soil Loss Equation (RUSLE) and the revised Morgan–Morgan–Finney (MMF) are well-known models, but not much information is available as regards their suitability in predicting post-fire soil erosion in forest soils. The lack of information is even more pronounced as regards post-fire rehabilitation treatments. The aim of the thesis was to perform an extensive research under the post fire hydrologic and erosive response subject. By understanding the effect of burn severity in ecosystems and its implications regarding post fire hydrological and erosive responses worldwide. Test the effect of different pre-fire land management practices (unplowed, downslope plowed and contour plowed) and time-since-fire, in the post fire hydrological and erosive response, between the two most common land uses in Portugal (pine and eucalypt). Assess the performance of two widely-known erosion models (RUSLE and Revised MMF), to predict soil erosion rates during first year following two wildfires of distinctive burn severity. Furthermore, to apply these two models considering different post-fire rehabilitation treatments in an area severely affected by fire. Improve model estimations of post-fire runoff and erosion rates in two different land uses (pine and eucalypt) using the revised MMF. To assess these improvements by comparing estimations and measurements of runoff and erosion, in two recently burned sites, as also with their post fire rehabilitation treatments. Model modifications involved: (1) focusing on intra-annual changes in parameters to incorporate seasonal differences in runoff and erosion; and (2) inclusion of soil water repellency in runoff predictions. Additionally, validate these improvements with the application of the model to other pine and eucalypt sites in Central Portugal. The review and meta-analysis showed that fire occurrence had a significant effect on the hydrological and erosive response. However, this effect was only significantly higher with increasing soil burn severity for inter-rill erosion, and not for runoff. This study furthermore highlighted the incoherencies between existing burn severity classifications, and proposed an unambiguous classification. In the case of the erosion plots with natural rainfall, land use factor affected annual runoff while land management affected both annual runoff and erosion amounts significantly. Time-since-fire had an important effect in erosion amounts among unplowed sites, while for eucalypt sites time affected both annual runoff and erosion amounts. At all studied sites runoff coefficients increase over the four years of monitoring. In the other hand, sediment concentration in the runoff, recorded a decrease during the same period. Reasons for divergence from the classic post-fire recovery model were also explored. Short fire recurrence intervals and forest management practices are viewed as the main reasons for the observed severe and continuing soil degradation. The revised MMF model presented reasonable accuracy in the predictions while the RUSLE clearly overestimated the observed erosion rates. After improvements: the revised model was able to predict first-year post-fire plot-scale runoff and erosion rates for both forest types, these predictions were improved both by the seasonal changes in the model parameters; and by considering the effect of soil water repellency on the runoff, individual seasonal predictions were considered accurate, and the inclusion of the soil water repellency in the model also improved the model at this base. The revised MMF model proved capable of providing a simple set of criteria for management decisions about runoff and erosion mitigation measures in burned areas. The erosion predictions at the validation sites attested both to the robustness of the model and of the calibration parameters, suggesting a potential wider application.As implicações dos fogos florestais na escorrência superficial e erosão dos solos têm sido objeto de estudo desde há vários anos. Como tal, é do conhecimento geral, que os fogos tendem a aumentar a atividade hidrológica e geomorfológica em todo o mundo e também nas zonas mediterrânicas. A severidade da queima do solo tem sido utilizada para descrever o impacto dos fogos nos solos e reconhecida como um fator decisivo no controle das taxas de erosão pós-fogo. No entanto, não existe uma definição única do termo e a relação entre severidade de queima do solo com a resposta hidrológica e erosiva não é ainda totalmente conhecida. Por outro lado, escasseiam os estudos com registos de taxas de erosão pós-fogo durante um período de quatro anos, nenhum dentro desse período com registos de escorrência superficial pós-fogo. Menos estudos ainda, que retratem a resposta erosiva pós-fogo, mencionando práticas de gestão florestal anteriores ao mesmo. No caso da modelação de erosão dos solos, apesar dos modelos aplicados ‒ a Equação Universal de Perdas do Solo Revista (RUSLE) e o modelo de Morgan-Morgan-Finney (MMF) ‒ serem bem conhecidos, a informação referente à sua aplicabilidade para prever taxas de erosão em solos florestais após o fogo é bastante limitada. No caso da aplicabilidade destes modelos, considerando tratamentos de mitigação após incêndio, ainda menos informação existe. O objetivo deste trabalho é o aprofundar do conhecimento relativo à resposta hidrológica e erosiva após incêndios florestais através do estudo dos efeitos da severidade de queima nos ecossistemas e das suas implicações na resposta hidrológica e erosiva em todo o mundo. Para este fim, testámos também o efeito de diferentes práticas de gestão florestal (não lavrado, lavrado no sentido do declive e lavrado segundo as curvas de nível), executadas previamente ao incêndio florestal, entre dois dos usos do solo mais comuns em Portugal: o pinheiro e o eucalipto. Testámos ainda a eficiência com que dois modelos, amplamente conhecidos (RUSLE e MMF revisto), conseguem prever, em duas severidades distintas e com tratamentos de reabilitação pós fogo, as taxas de erosão durante o ano que seguiu ao incêndio florestal. Com essa informação, que veio melhorar as estimativas, alterámos o modelo e verificámos a sua eficiência, tanto nas previsões de escorrência superficial como na erosão do solo em pós-fogo e em pós-fogo com tratamentos de reabilitação. Essas alterações, que consistiam em (1) passar todos os inputs numa escala sazonal para incorporar as variações sazonais sentidas na formação de escorrência superficial e erosão do solo, e (2) inclusão do efeito hidrófobo do solo à água nas previsões da escorrência superficial. Adicionalmente, validar estas melhorias noutra área florestal independente no centro de Portugal para pinhal e eucaliptal, pós-fogo e pós-fogo com tratamentos de reabilitação. A revisão e a meta-análise demonstraram que a ocorrência de um fogo florestal provoca alterações significativas na resposta hidrológica e erosiva. No entanto, este efeito só é significativamente diferente com o aumento da severidade da queima do solo para a erosão e não para a geração de escorrência superficial. Este estudo também aludiu a incoerência entre várias classificações de severidade de queima e propõe ainda uma classificação não ambígua. No caso das parcelas de erosão com chuva natural, verificou-se que o uso do solo é um fator que afeta a geração de escorrência; em contrapartida, a gestão florestal afeta tanto a escorrência como a erosão do solo. O tempo decorrido desde o incêndio surge como fator de elevada importância entre locais não lavrados, relativamente às perdas de solo, e entre eucaliptais, relativamente à escorrência e erosão. Em todos os locais os coeficientes de escorrência aumentaram do primeiro para o quarto ano de estudo. Noutra nota, notou-se um decréscimo nas concentrações de sedimentos na escorrência durante o mesmo período. Foi explorada a discrepância entre este estudo e entre os modelos clássicos de recuperação pós-fogo; também o curto intervalo entre fogos e as constantes práticas de gestão florestal são vistas como as principais razões pela severa e continuada degradação dos solos. O modelo de MMF revisto apresentou uma razoável acuidade nas previsões enquanto que, o RUSLE claramente sobrestimou as taxas de erosão observadas. Ambos os modelos demonstraram capacidades para serem usados como ferramentas operacionais para ajudarem gestores a determinar áreas de risco de erosão pós-fogo e a tomarem ações prioritárias. O Modelo MMF revisto permitiu determinar as taxas de erosão durante o primeiro ano, após o fogo, para os dois usos do solo estudados: o pinheiro e o eucalipto. Essas previsões melhoraram com a implementação da modelação sazonal e com a inclusão da hidrofobia do solo à água para as previsões de escorrência. Por fim, o modelo de MMF revisto provou ser capaz de providenciar um conjunto de critérios para ajudar à tomada de decisões por parte dos gestores relativamente à escorrência, erosão e tratamentos de mitigação em áreas recentemente ardidas. Este modelo sugere, segundo os resultados obtidos aquando da validação e calibração, uma elevada robustez e um potencial de ser aplicado a outras áreas

Effectiveness of hydromulching to reduce runoff and erosion in a recently burnt pine plantation in central Portugal

Forest fires can greatly increase runoff and surface erosion rates. Post‐fire soil erosion control measures are intended to minimize this response and facilitate ecosystem recovery. In a few recent cases, hydromulch has been applied, and this consists of a mixture of organic fibers, water and seeds. The objectives of this research were to (i) analyze the effectiveness of hydromulch in reducing post‐fire runoff and sediment production and (ii) determine the underlying processes and mechanisms that control post‐fire runoff and erosion. After a wildfire occurred in August 2008, 14 plots ranging in size from 0·25 to 10 m2 were installed on a 25 degree slope in a burnt pine plantation that had also been subjected to salvage logging. Half of the plots were randomly selected and treated with hydromulch. One of two slope strips adjacent to the plots was also hydromulched and used for monitoring some soil properties. Measurements made in each of the first 3 years following the wildfire included (i) the plot‐scale runoff volumes and sediment yields; (ii) soil shear strength, soil moisture, and soil water repellency; and (iii) surface cover. The hydromulch reduced overland flow volume by 70% and soil erosion by 83%. The decrease in runoff was attributed to the increase in soil water retention capacity and the decrease in soil water repellency, whereas the reduction in soil erosion was initially attributed to the protective cover provided by the hydromulch and lately to an enhanced vegetative regrowth in the third year after burning.publishe

Long‐term impacts of post‐fire mulching on ground‐dwelling arthropod communities in a eucalypt plantation

In the past decades, Portugal like several other Mediterranean countries has been affected by frequent wildfires. This has led to various field tests of post-fire soil conservation measures and, in particular, mulching with forest slash residues. While forest residue mulching was shown to be highly effective in reducing post-fire erosion, its side effects on soil fauna communities have not been studied and are also difficult to predict from the – scarce – literature on mulch effects in general. Therefore, this study compared the abundance, diversity and taxonomic and functional composition of the ground-dwelling arthropod communities of three mulched and, as control, three untreated erosion plots of roughly 100 m2 that had been installed in a eucalypt plantation almost immediately after a wildfire in 2010, some five years earlier. This was done using three pitfall traps per plot, placed at the lower, middle and upper part of the study slope. Roughly five years after mulching, its impacts on the ground-dwelling arthropod were rather limited, especially compared to its effect on overall soil erosion rates. One of the few exceptions was the abundance of the Hymenoptera – one of the most frequently occurring orders – which was significantly lower in the mulched than control plots. This and other near significant mulching impacts found in this study plainly justify a follow-up study on shortterm effects.publishe

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved

Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora

Global variation in postoperative mortality and complications after cancer surgery: a multicentre, prospective cohort study in 82 countries

© 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 licenseBackground: 80% of individuals with cancer will require a surgical procedure, yet little comparative data exist on early outcomes in low-income and middle-income countries (LMICs). We compared postoperative outcomes in breast, colorectal, and gastric cancer surgery in hospitals worldwide, focusing on the effect of disease stage and complications on postoperative mortality. Methods: This was a multicentre, international prospective cohort study of consecutive adult patients undergoing surgery for primary breast, colorectal, or gastric cancer requiring a skin incision done under general or neuraxial anaesthesia. The primary outcome was death or major complication within 30 days of surgery. Multilevel logistic regression determined relationships within three-level nested models of patients within hospitals and countries. Hospital-level infrastructure effects were explored with three-way mediation analyses. This study was registered with ClinicalTrials.gov, NCT03471494. Findings: Between April 1, 2018, and Jan 31, 2019, we enrolled 15 958 patients from 428 hospitals in 82 countries (high income 9106 patients, 31 countries; upper-middle income 2721 patients, 23 countries; or lower-middle income 4131 patients, 28 countries). Patients in LMICs presented with more advanced disease compared with patients in high-income countries. 30-day mortality was higher for gastric cancer in low-income or lower-middle-income countries (adjusted odds ratio 3·72, 95% CI 1·70–8·16) and for colorectal cancer in low-income or lower-middle-income countries (4·59, 2·39–8·80) and upper-middle-income countries (2·06, 1·11–3·83). No difference in 30-day mortality was seen in breast cancer. The proportion of patients who died after a major complication was greatest in low-income or lower-middle-income countries (6·15, 3·26–11·59) and upper-middle-income countries (3·89, 2·08–7·29). Postoperative death after complications was partly explained by patient factors (60%) and partly by hospital or country (40%). The absence of consistently available postoperative care facilities was associated with seven to 10 more deaths per 100 major complications in LMICs. Cancer stage alone explained little of the early variation in mortality or postoperative complications. Interpretation: Higher levels of mortality after cancer surgery in LMICs was not fully explained by later presentation of disease. The capacity to rescue patients from surgical complications is a tangible opportunity for meaningful intervention. Early death after cancer surgery might be reduced by policies focusing on strengthening perioperative care systems to detect and intervene in common complications. Funding: National Institute for Health Research Global Health Research Unit

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

© 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licenseBackground: Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide. Methods: A multimethods analysis was performed as part of the GlobalSurg 3 study—a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital. Findings: Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3·85 [95% CI 2·58–5·75]; p<0·0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63·0% vs 82·7%; OR 0·35 [0·23–0·53]; p<0·0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer. Interpretation: Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised. Funding: National Institute for Health and Care Research