Human and environmental factors influencing fire trends in different forest ecosystems

Consultable des del TDXTítol obtingut de la portada digitalitzadaLa mayoría de los bosques del planeta, exceptuando, quizá, el cinturón más húmedo del trópico, han sufrido perturbaciones recurrentes por incendios, desde hace miles de años. Sin embargo, en el último siglo, la combinación de factores socio-económicos y ambientales han alterado la frecuencia y distribución de incendios en casi todos los ecosistemas forestales. Esta mala distribución del fuego ha conllevado la acumulación de este elemento perturbador en ecosistemas poco adaptados a su presencia (e.g. bosques tropicales húmedos), mientras que otros ecosistemas han sufrido los efectos de las políticas de supresión de incendios (e.g. bosques templados norteamericanos). Entre las consecuencias de estas alteraciones, algunas se refieren a variaciones en el régimen de incendios, con implicaciones en términos de conservación forestal, impacto ecológico, económico y social. La presente tesis analiza la influencia de factores ambientales y socio-económicos en algunas características del régimen de incendios en ecosistemas tropicales y mediterráneos. En el ámbito tropical, la zona de estudio es el Estado mexicano de Chiapas, y los objetivos son básicamente dos: 1) caracterizar el régimen de incendios en el Estado, en términos de frecuencia de incendios, distribución, áreas y ecosistemas afectados, tipología de incendios, causalidad, y su interacción con algunos factores como el fenómeno de El Niño, la distribución de la tenencia de la tierra o la variación de las precipitaciones. 2) Analizar la influencia relativa de factores ambientales frente a factores socio-económicos, en años de condiciones climáticas normales y años de El Niño. El objetivo último era determinar variaciones en la afectación de los principales ecosistemas y listar los factores más importantes a considerar, a nivel de gestión forestal contra incendios. A nivel de ecosistemas mediterráneos, se seleccionó el incendio del Solsonés 1998, como caso estudio, siendo los principales objetivos: 3) Seleccionar la metodología de clasificación post-incendio más eficiente entre varias técnicas analizadas (teledetección y muestreo de campo). 4) Analizar la influencia de diversos factores ambientales en la formación de islas de vegetación en un gran incendio, empleando las laderas como unidad espacial. 5) Verificar la importancia de la estructura forestal y la continuidad del combustible en la heterogeneidad final de las severidades de afectación de un incendio. En relación a estos objetivos, las principales aportaciones de este estudio han sido, en lo referente a ecosistemas tropicales: La descripción de los incendios en Chiapas como mayoritariamente superficiales, afectando principalmente a estratos no arbóreos, de grandes dimensiones, de origen antrópico y con cierta propensión a afectar zonas protegidas. La aportación clave sin embargo, hace referencia a la demostración de la importancia de El Niño en la afectación de los ecosistemas tropicales húmedos, principalmente influenciado por la presencia de pastos alrededor de bosques fragmentados. El cambio de importancia relativa de los factores ambientales en años de no-ENSO frente a la mayor importancia de los factores socio-económicos en años de ENSO. También se puede remarcar el cambio de ecosistema afectado condicionado por el tipo de año (condiciones climáticas normales o extremas, ENSO o no ENSO: pino-encino versus bosques tropicales húmedos). En relación a los bosques mediterráneos, las técnicas más sencillas de teledetección resultaron las adecuadas para la identificación de islas. La formación de estas islas se ve condicionada por el tamaño y orientación y pendiente de las laderas, así como la cantidad y madurez de los rodales afectados, siendo las laderas más extensas, de orientación noroeste, de mayor pendiente, con mayores extensiones forestales y bosques más maduros (en términos de mayores tamaños), las más propicias a formar islas. Las características estructurales de los rodales fue de gran importancia para predecir la supervivencia forestal en zonas de condiciones climáticas moderadas.The great majority of the forests of the world, excepting perhaps, the wettest belt of the tropics, have been burned over, at more or less frequent intervals, for many thousands of years. In the last century however, a combination of human and environmental factors have altered the frequency and distribution of fire, almost everywhere. This maldistribution of fire has resulted in an accumulation of this element in ecosystems not adapted to high frequencies of fire (i.e. tropical and sub-tropical areas), while other ecosystems have suffered the effects of fire suppression policies (i.e. north American temperate forests). Among the consequences of these alterations, some of them refer to variations in fire regimes, with implications in terms of forest conservation, ecological, economic and social impact. The present thesis analyses the influence of environmental and socio-economic factors for certain elements of the fire regime in tropical and Mediterranean ecosystems. In tropical areas, the study case relates to the tropical Mexican State of Chiapas, and the objectives are basically two: 1) to characterize the fire regime in the State, in terms of frequency of fires, fire distribution, areas and ecosystems affected, type of fires, causality, and their interaction with some factors like the phenomenon of El Niño, the land distribution, or the variation of rainfall values. 2) To analyse the relative influence of environmental factors versus socio-economic factors, in years of normal climatic conditions and years of El Niño. The final objective is to detect variations in the affectation of the major ecosystems and to list the most important factors to consider for forest fire management. For the Mediterranean ecosystems, the fire of Solsonés 1998 was selected as case study. Main objectives are: 3) To select the most efficient methodology for post-fire classification among several techniques: image classification and field survey. 4) To determine the influence of diverse environmental factors in the formation of vegetation islands inside a large forest fire, using «slope», as the spatial unit. 5) To verify the importance of forest structure and fuel continuity in the final heterogeneity of fire severities in a large fire. In relation to these objectives, the main contributions of this study are, with respect to tropical ecosystems: The characterization of fires in Chiapas, as in other tropical areas, mainly as superficial fires, frequently affecting non-arboreal layers. Major problems focus on large forest fires, which are responsible for the major burned areas. Fires are mainly human related and display certain propensity to affect protected zones. The key contribution nevertheless, refers to the major importance of El Niño in the affectation of humid tropical ecosystems. This is specially enhanced by the presence of cattle pasture surrounding the fragmented forests. The shift on the importance of environmental factors in years of no-ENSO versus the greater importance of socio-economic factors in years of ENSO, is also a major achievement. Moreover, shifts in ecosystem affectation have also been observed depending on the climatic conditions: pine-oak in no-ENSO years versus humid tropical forests in ENSO years. Regarding the Mediterranean forests, the simplest techniques of teledetection were the best performing ones for island identification. The formation of these islands is conditioned by the size and aspect of the slopes, as well as by the amount and maturity of the affected patches. Most extensive slopes, north-western orientations, more abrupt, larger forest extensions per slope, and more mature forests (in terms of greater sizes), are the most suitable combination of factors to form islands. This formation of islands does not have, therefore, a random distribution. Besides, the structural characteristics of the forest patches was confirmed to be of great importance to predict the forest survival in areas were fire burned under moderate climatic conditions. Larger patches and larger trees are the ones that will survive fire the best

Drivers of mangrove vulnerability and resilience to tropical cyclones in the North Atlantic Basin

The North Atlantic Basin (NAB) has seen an increase in the frequency and intensity of tropical cyclones since the 1980s, with record-breaking seasons in 2017 and 2020. However, little is known about how coastal ecosystems, particularly mangroves in the Gulf of Mexico and the Caribbean, respond to these new “climate normals” at regional and subregional scales. Wind speed, rainfall, pre-cyclone forest height, and hydro-geomorphology are known to influence mangrove damage and recovery following cyclones in the NAB. However, previous studies have focused on local-scale responses and individual cyclonic events. Here, we analyze 25 years (1996–2020) of mangrove vulnerability (damage after a cyclone) and 24 years (1996–2019) of short-term resilience (recovery after damage) for the NAB and subregions, using multi-annual, remote sensing-derived databases. We used machine learning to characterize the influence of 22 potential variables on mangrove responses, including human development and long-term climate trends. Our results document variability in the rates and drivers of mangrove vulnerability and resilience, highlighting hotspots of cyclone impacts, mangrove damage, and loss of resilience. Cyclone characteristics mainly drove vulnerability at the regional level. In contrast, resilience was driven by site-specific conditions, including long-term climate trends, pre-cyclone forest structure, soil organic carbon stock, and coastal development (i.e., proximity to human infrastructure). Coastal development is associated with both vulnerability and resilience at the subregional level. Further, we highlight that loss of resilience occurs mostly in areas experiencing long-term drought across the NAB. The impacts of increasing cyclone activity on mangroves and their coastal protection service must be framed in the context of compound climate change effects and continued coastal development. Our work offers descriptive and spatial information to support the restoration and adaptive management of NAB mangroves, which need adequate health, structure, and density to protect coasts and serve as Nature-based Solutions against climate change and extreme weather events.This research was made possible thanks to the generous support from the BNP-PARIBAS Foundation on their 2019 Climate and Biodiversity Initiative call through the CORESCAM (“Coastal Biodiversity Resilience to Increasing Extreme Events in Central America”) project.Peer reviewe

Stakeholders’ Perceptions of Nature-Based Solutions for Hurricane Risk Reduction Policies in the Mexican Caribbean

Nature-based solutions (NbSs) have long recognized the value of coastal and marine ecosystem management and associated ecosystem services as useful tools for climate change mitigation (e.g., blue carbon) and adaptation (e.g., coastal protection against flooding and storm surges). However, NbSs remain poorly acknowledged and mostly absent from coastal planning for disaster risk reduction policies in the Caribbean, as well as from ex-post disaster reconstruction funds. With the increasing frequency and intensity of hurricanes in the region, NbSs are now more needed than ever. Taking Mexico as a representative case study for the wider Caribbean, we here seek to identify and analyze the barriers and opportunities perceived by relevant stakeholders for mainstreaming coastal-marine NbSs into coastal management and disaster risk reduction policies (e.g., mangroves as green infrastructure) to protect coastal societies and national economies against hurricanes. We conduct semi-structured, in-depth interviews with twenty stakeholders covering academic, governmental, tourism, NGO, coastal planning, and financial domains. Among the twenty-three identified barriers, governance, institutional, financial, and human-capacity aspects are the most dominant perceptions behind the current lack of NbS implementation. Future action for the policy integration of NbSs requires widespread political will and better quantification of both the provision of ecosystem services and their economic benefits under conventional markets.The authors would like to express their gratitude to the BNP-PARIBAS Foundation for funding support on their 2019 call on Climate and Biodiversity, under the CORESCAM project. Research has also been supported by Summit Foundation, and FFEM through grants admonished by the Smithsonian Institution and Mesoamerican Reef Fund, as well as the Smithsonian Marine Station contribution number: 1183. The BLUEFLUX project acknowledges core support from the NASA Carbon Monitoring System and NASA’s Terrestrial Ecology Program. We would also like to acknowledge all interviewees involved in this research. RMR-C would like to acknowledge salary contribution from the LIFE-DICET project and gratitude to the European University Institute.Peer reviewe

Options for monitoring and estimating historical carbon emissions from forest degradation in the context of REDD+

Measuring forest degradation and related forest carbon stock changes is more challenging than measuring deforestation since degradation implies changes in the structure of the forest and does not entail a change in land use, making it less easily detectable through remote sensing. Although we anticipate the use of the IPCC guidance under the United Framework Convention on Climate Change (UNFCCC), there is no one single method for monitoring forest degradation for the case of REDD+ policy. In this review paper we highlight that the choice depends upon a number of factors including the type of degradation, available historical data, capacities and resources, and the potentials and limitations of various measurement and monitoring approaches. Current degradation rates can be measured through field data (i.e. multi-date national forest inventories and permanent sample plot data, commercial forestry data sets, proxy data from domestic markets) and/or remote sensing data (i.e. direct mapping of canopy and forest structural changes or indirect mapping through modelling approaches), with the combination of techniques providing the best options. Developing countries frequently lack consistent historical field data for assessing past forest degradation, and so must rely more on remote sensing approaches mixed with current field assessments of carbon stock changes. Historical degradation estimates will have larger uncertainties as it will be difficult to determine their accuracy. However improving monitoring capacities for systematic forest degradation estimates today will help reduce uncertainties even for historical estimates

¿Qué queda de mí?

Este libro es una reclamación a quienes hemos sido, somos o seremos docentes. A quienes no hemos respetado a las personas que se han puesto junto a nosotros y nosotras, confiando su bien más preciado: la libertad. Estas páginas denuncian cada vez que convertimos una visión en la visión, una emoción en la emoción, un saber en el saber, un comportamiento en el comportamiento. Es un grito contra la imposición, la normalización, la neutralización y la universalización de una perspectiva particular. Una pugna contra cada proceso que no se ha conectado con las vidas de los aprendices. Un texto colaborativo realizado por alumnado de Educación y Cambio Social en el Grado en Educación Infantil de la Universidad de Málaga y coordinado por Ignacio Calderón Almendros

Cost-effective compensation to avoid carbon emissions from forest loss: An approach to consider price-quantity effects and risk-aversion

Analyses were carried out on financial compensation to avoid loss of tropical forests and related carbon (C) emissions when marginal financial yield declined for land-use options with extended areas, and when a risk-averting perspective (modeled according to financial theory around the capital asset pricing model) is assumed. The approach in this study was to consider natural forest, forest plantation, pasture, and cropland simultaneously to investigate how an optimized land-use distribution may reduce the amount of compensation necessary to avoid C emissions from forest loss. The financial compensations derived were as high as US$176 per hectare per year when comparing natural forests only with the most profitable alternative (croplands). However, compensation decreased to US$ 124 for risk-neutral decision-makers, who would strive for optimized land-use allocation, and to only US$ 47 per hectare per year for risk-avoiders, who would look to maximize the reward-to-variability ratio. Sensitivity analyses indicated that the compensation under risk-aversion increased much less than under risk-ignoring when increased productivity of agricultural land-use or growing demand for agricultural products was simulated. It was concluded that considering appropriate diversification strategies and the well documented human behavior to avoid risks is an important step in developing cost-effective compensation policies.Financial modeling of land-use shares Uncertainty Risk aversion Carbon compensation Land diversification Endogeneity of tropical land-use Indirect land use change (iLUC)

Guía para la restauración ecológica de manglares: Lecciones aprendidas

El objetivo de esta Guía es orientar y fortalecer las capacidades locales de todo aquel interesado en recuperar áreas de manglar. Con esta guía se pretende apoyar el desarrollo de propuestas, planear, ejecutar y dar seguimiento a programas de restauración de manglares, y se expone, más allá de metodologías específicas, una estrategia que incluye procesos para la integración de los componentes sociales, económicos y ecológicos. La estrategia es presentada de forma ordenada y estandarizada en tres fases generales: la planeación, la implementación y evaluación. El alcance de su aplicación incluye a todo tipo de manglar y nivel de impacto gracias a sus bases conceptuales y técnicas que consideran los fundamentos de la fisiología de especies, las características de sus hábitats, conceptos de poblaciones, comunidades, ecosistemas y del paisaje. El manglar, como ecosistema anfibio entre el mar y la tierra, lleva sufriendo de los impactos de ambos sectores. Por el lado del mar: erosión, tormentas e incremento del nivel del mar; y por el lado de la costa: deforestación, incendios y gestión agrícola en las cuencas costeras con consecuencias en los recursos hídricos que alcanzan los mangles. América Central y el Caribe son regiones del planeta donde existe un incremento significativo de la intensidad y la frecuencia de los eventos climáticos extremos. Entre ellos los huracanes, las sequias y las inundaciones, con efectos severos sobre la estabilidad de los ecosistemas costeros y sus servicios ecosistémicos. La región Mesoamericana y el Caribe engloba gran cantidad de Islas Estado cuya estabilidad ecológica, económica y social depende del bienestar de sus ecosistemas costeros como el manglar. Por lo que se hace necesario, más que nunca, promocionar las Opciones Basadas en Naturaleza como la Infraestructura Verde, como forma de proteger la costa, sus sociedades y su calidad de vida. Los ecosistemas de carbono azul proveen gran cantidad de servicios ecosistémicos (protección, provisión de alimentos, captación de CO2, producción de madera, hábitat para biodiversidad). Restaurarlos es un beneficio fundamental para la sociedad. Actualmente los planes de reducción de riesgos y de reconstrucción tras eventos extremos no incluyen las Soluciones Basadas en Naturaleza. Las Naciones Unidas han declarado el 2021-2030 como la Década de la Restauración Ecológica. La región ha visto un incremento de la restauración de arrecifes, pero mucho menos esfuerzos se han visto en los bosques costeros, como los manglares, las marismas y los pastos marinos (que constituyen el carbono azul). La región ha mostrado su compromiso con el Reto Bonn y su Iniciativa 20x20, que representa una excelente oportunidad para incrementar la restauración de manglares degradados o deforestados. Sin embargo, la Iniciativa 20x20 no incluye a los manglares entre sus objetivos de restauración. Esta guía pretende apoyar esa ventana de oportunidad

Land Restoration in Latin America and the Caribbean: An Overview of Recent, Ongoing and Planned Restoration Initiatives and Their Potential for Climate Change Mitigation

Land degradation is a globally recognized problem and restoration of degraded land is currently high on the international agenda. Forest landscape restoration and other restorative ecosystem management activities are important measures that contribute towards reaching the objectives of the Bonn Challenge, which aims to restore 350 million hectares by 2030. In this context, many restoration projects are being planned and implemented in Latin America and the Caribbean (LAC). We present an overview of the location, goals and activities, and an estimated climate change mitigation potential of 154 recent, ongoing and planned restoration projects in LAC. Our analysis suggests that most projects are located in the humid tropics and less attention is paid to drylands. Increasing vegetation cover, biodiversity recovery and recovery of ecological processes are the most common goals. Restorative activities to fulfil these goals were diverse and were related to the type and source of funding that projects receive. For example, projects implemented through the Forest Investment Program (FIP) and the Global Environment Facility (GEF) generally rely on natural or assisted regeneration over large areas (>20,000 ha), whereas Clean Development Mechanism (CDM) projects establish forest plantations, often including exotic monocultures, in smaller project areas (<5000 ha). Projects that are specifically implemented within the scope of Initiative 20 × 20 and other local initiatives that target the local environmental problems, are more varied and rely on a wider portfolio of restorative activities, such as erosion control, exclusion of grazing and mixed plantations. These projects are usually implemented in smaller project areas (<5000 ha). All projects had the potential to contribute to climate change mitigation by storing additional forest aboveground biomass through natural regeneration, assisted regeneration or establishing a plantation. Further analysis of the implemented activities is an important next step to investigate their effectiveness in terms of goals achieved under Initiative 20 × 20 and the Bonn Challenge. This would provide information for future restoration projects and upscaling of restorative activities in a wider area