Udo Nehren

Impact of natural climate change and historical land use on landscape development in the Atlantic Forest of Rio de Janeiro, Brazil

Climate variations and historical land use had a major impact on landscape development in the Brazilian Atlantic Forest (Mata Atlântica). In southeast Brazil, rainforest expanded under warm-humid climate conditions in the late Holocene, but have been dramatically reduced in historical times. Nevertheless, the numerous remaining forest fragments are of outstanding biological richness. In our research in the Atlantic Forest of Rio de Janeiro we aim at the reconstruction of the late Quaternary landscape evolution and an assessment of human impact on landscapes and rainforests. In this context, special focus is given on (a) effects of climate variations on vegetation cover, soil development, and geomorphological processes, and (b) spatial and temporal land use and landscape degradation patterns. In this paper we present some new results of our interdisciplinary research in the Serra dos Órgãos mountain range, state of Rio de Janeiro.

Mangrove biomass carbon stock mapping of the Karimunjawa Islands using multispectral remote sensing

ABSTRACT Among vegetated coastal habitats, mangrove forests are among the densest carbon pools. They store their organic carbon in the surrounding soil and thus the sequestered carbon stays in the sediment for a long time and cannot be easily returned to the atmosphere. Additionally, mangroves also provide various important ecosystem services in coastal areas and surroundings. Accordingly, it is important to understand the distribution of biomass carbon stock in mangrove habitats in a spatial and temporal context, not only to reduce CO2 concentrations in the atmosphere, but also for their sustainability. The objectives of this research are to map the mangrove carbon stock and estimate the total biomass carbon stock sheltered by mangrove forests, with the Karimunjawa Islands as a study site, using the widely available passive remote sensing system ALOS AVNIR-2. The modelling and mapping of mangrove carbon stock incorporates the integration of image pixel values and mangroves field data via empirical modelling. Vegetation indices and PC bands at different levels of radiometric corrections were all used as the input in the mangrove carbon stock modelling so that the effectiveness and sensitivity of different image transformations to particular radiometric correction levels could be analysed and understood. Afterward, the accuracy and effectiveness of each mangrove carbon stock-mapping routine was compared and evaluated. The accuracy of the best mangrove above-ground carbon stock (AGC) map modelled from vegetation index is 77.1% (EVI1, SE 5.89 kg C m−2), and for mangrove below-ground carbon stock (BGC) it is 60.0% (GEMI, SE 2.54 kg C m−2). The mangrove carbon stock map from ALOS AVNIR-2 PC bands showed a maximum accuracy of 77.8% (PC2, SE 5.71 kg C m−2) and 60.8% (PC2, SE 2.48 kg C m−2) for AGC and BGC respectively. From the resulting maps, the Karimunjawa Islands are estimated to shelter 96,482 tonnes C of mangroves AGC with a mean value of 21.64 kg C m−2 and 24,064 tonnes C of mangroves BGC with a mean value of 5.39 kg C m−2. Potentially, there are approximately 120,546 tonnes C of mangrove biomass carbon stock in the Karimunjawa Islands. Remote-sensing reflectance can successfully model mangrove carbon stock based on the relationship between mangrove canopy properties, represented by leaf area index (LAI) and the tree or root biomass carbon stock. The accuracy of the mangrove carbon stock map is subject to errors, which are sourced mainly from: (1) the absence of a species-specific biomass allometric equation for several species present in the study area; (2) the generalized standard conversion value of mangrove biomass to mangrove carbon stock; (3) the relationship between mangrove reflectance and mangrove LAI; (4) the relationship between mangrove reflectance and above-ground mangrove biomass and carbon stock due to its relationship with LAI; (5) the relationship between mangrove LAI and mangrove below-ground parts; (6) the inability to perform mangrove carbon stock modelling at the species level due to the complexities of the mangrove forest in the study area; (7) background reflectance and atmospheric path radiance that could not be completely minimized using image radiometric corrections and transformations; and (8) spatial displacement between the actual location of the mangrove forest in the field and the corresponding pixel in the image. The availability of mangrove biomass carbon stock maps is beneficial for carrying out various management activities, and is also very important for the resilience of mangroves to changing environments.

Ecosystem-Based Disaster Risk Reduction and Adaptation in Practice

This book is a compilation of recent developments in the field of ecosystem-based disaster risk reduction and climate change adaption (Eco-DRR/CCA) globally. It provides further evidence that ecosystem-based approaches make economic sense, and showcases how research has progressively filled knowledge gaps about translating this concept into practice. It presents a number of methods, and tools that illustrate how Eco-DRR/CCA has been applied for various ecosystems and hazard contexts around the world. It also discusses how innovative institutional arrangements and policies are shaping the field of Eco-DRR/CCA. The book is of relevance to scientists, practitioners, policy-makers and students in the field of ecosystem management for disaster risk reduction and climate change adaptation.

Charcoal production through selective logging leads to degradation of dry woodlands: a case study from Mutomo District, Kenya

Provision of woodfuel is an important ecosystem service of dry forests and woodlands. However, charcoal production through selective logging of preferred hardwood species has the potential to alter the physiognomic composition of the residual or re-growth woodlands and may lead to their deterioration and degradation. This study, conducted through forest inventory in Mutomo District in Kenya, assessed the impact of charcoal production on unprotected dry woodlands in terms of tree density, targeted species basal area, species richness, evenness and Shannon diversity. The parameters of the disturbed woodlands were evaluated for significant differences with those of the neighbouring protected Tsavo East National Park, which served as a reference for an ecologically undisturbed ecosystem. By evaluating a consequence of tree harvesting for charcoal production, this study confirmed the overall significant differences between the protected and unprotected woodlands in all the tested parameters. To confirm if the differences in the land-covers of the woodlands had any influence on their degradation, all mentioned parameters were compared between the four differentiated classes and their respective control plots in the protected areas. At the “land-cover level”, the statistically significant difference in the basal area of tree species preferred for charcoal production between the protected and unprotected open trees confirms that the class with a high density of large mature trees is the prime target of charcoal producers. In addition, there seems to be a general trend of lower values of tree species richness, evenness and Shannon diversity for the unprotected woodlands subjected to charcoal production. On the other hand, the disturbed woodlands display the potential to recover through their comparably high saplings density. The findings make an important contribution to the discourse on the impact of charcoal production in dry woodlands, a topic that is highly controversial among researchers.

Natural Hazards and Climate Change Impacts in the State of Rio de Janeiro: A Landscape Historical Analysis

Floods, landslides, and mudslides are frequent phenomena in Rio de Janeiro state (RJ). In the past decades, several catastrophic events have occurred and caused severe damages to people and infrastructure. In contrast, the persistent droughts that affected Southeast Brazil between 2014 and 2017 are phenomena that were not known earlier – at least in such frequency and intensity. Climate scenarios predict that extreme events will further increase in the future leading to increased heavy rainfall events on the one hand and longer dry spells on the other. In this chapter, we provide an overview on the different types of natural hazards, their occurrence (frequency) and intensity, and historical disasters caused by these hazards in RJ. Furthermore, we reconstruct in how far climate variability and human impact (in particular deforestation) affected the occurrence of hydrometeorological hazards in the Holocene. Based on the analysis of historical trends and modeling outcomes under different climate scenarios, we discuss potential future hazards.

Preliminary work of mangrove ecosystem carbon stock mapping in small island using remote sensing: above and below ground carbon stock mapping on medium resolution satellite image

Mangrove forest is an important ecosystem located in coastal area that provides various important ecological and economical services. One of the services provided by mangrove forest is the ability to act as carbon sink by sequestering CO2 from atmosphere through photosynthesis and carbon burial on the sediment. The carbon buried on mangrove sediment may persist for millennia before return to the atmosphere, and thus act as an effective long-term carbon sink. Therefore, it is important to understand the distribution of carbon stored within mangrove forest in a spatial and temporal context. In this paper, an effort to map carbon stocks in mangrove forest is presented using remote sensing technology to overcome the handicap encountered by field survey. In mangrove carbon stock mapping, the use of medium spatial resolution Landsat 7 ETM+ is emphasized. Landsat 7 ETM+ images are relatively cheap, widely available and have large area coverage, and thus provide a cost and time effective way of mapping mangrove carbon stocks. Using field data, two image processing techniques namely Vegetation Index and Linear Spectral Unmixing (LSU) were evaluated to find the best method to explain the variation in mangrove carbon stocks using remote sensing data. In addition, we also tried to estimate mangrove carbon sequestration rate via multitemporal analysis. Finally, the technique which produces significantly better result was used to produce a map of mangrove forest carbon stocks, which is spatially extensive and temporally repetitive.

Priority areas for watershed service conservation in the Guapi-Macacu region of Rio de Janeiro, Atlantic Forest, Brazil

IntroductionLand use intensification and urbanisation processes are degrading hydrological ecosystem services in the Guapi-Macacu watershed of Rio de Janeiro. A proposal to pay farmers to restore natural watershed services might be an alternative to securing the water supply in the long-term for the around 2.5 million urban water users in the study region. This study quantifies the costs of changing current land use patterns to enhance watershed services and compares these costs to the avoided costs associated with water treatment for public supply.MethodsWe use farm-household data to estimate the opportunity costs of abandoning current land uses for the recovery of natural vegetation; a process that is very likely to improve water quality in terms of turbidity due to reduced inputs from erosion. Opportunity cost estimates are extrapolated to the watershed scale based on remote sensing land use classifications and vulnerability analysis to identify priority zones for watershed management interventions. To assess the potential demand for watershed services, we analyse water quality and treatment cost data from the main local water treatment plant.ResultsChanging agricultural land uses for watershed services provision generally comes at high opportunity costs in our study area near to the metropolis of Rio de Janeiro. Alternative low cost watershed conservation options do exist in the livestock production sector. These options have the potential to directly reduce the amount of sediments and nutrients reaching the water bodies, and in turn decrease the costs of treatment needed for drinking water. Land cover changes at the scale needed to improve water quality will, nonetheless, likely exceed the cost of additional investments in water treatment.ConclusionsThe state water utility companys willingness to pay for watershed services alone will not be enough to induce provision of additional watershed services. We conclude that monetary incentives conditioned on specific adjustments to existing production systems could still have a complementary role to play in improving watershed services. However, we note that our willingness to pay analysis focusses on only one of the potentially wide range of ecosystem services provided by natural vegetation in the Guapi-Macacu watershed. Factoring these ecosystem services into the willingness to pay equation is likely to change our assessment in favour of additional conservation action, be it through PES or other policy instruments.

Defining New Pathways for Ecosystem-Based Disaster Risk Reduction and Adaptation in the Post-2015 Sustainable Development Agenda

This chapter seeks to articulate future directions in the field of Eco-DRR/CCA, in the context of the new post-2015 sustainable development agenda. It synthesises the experiences featured in this book and highlights the key challenges and opportunities in advancing Eco-DRR/CCA approaches. Four main themes are discussed: demonstrating the economic evidence of Eco-DRR/CCA; decision-making tools for Eco-DRR/CCA; innovative institutional arrangements and policies for mainstreaming Eco-DRR/CCA; and research gaps. The major global policy agreements in 2015 are examined for their relevance in promoting Eco-DRR/CCA implementation in countries. Finally, the authors reflect on a new agenda for Eco-DRR/CCA and outline some of the key elements required to significantly advance and scale-up Eco-DRR/CCA implementation globally.

Pasture Degradation in South East Brazil: Status, Drivers and Options for Sustainable Land Use Under Climate Change

The landscapes of the Atlantic Forest region of Southeast Brazil (SE Brazil) have suffered from a long-term historical deforestation and degradation. The vast majority of former forest areas had been transformed into sugar cane and coffee plantations. Especially in the state of Rio de Janeiro, these crops are no longer economically viable and most of the former plantations have been converted into cattle pastures. Due to unsuitable environmental conditions and unsustainable management, most of these pastures are nowadays highly degraded. Taking into account projected climate change with increasing droughts and pronounced heavy rainfalls in SE-Brazil, this pasture landscape is about to lose its socio- ecological resilience. Before this background, this paper analyses the status and drivers of pasture degradation in the Brazilian state of Rio de Janeiro. Moreover, it addresses possible options for pasture rehabilitation based on a case study carried out within the framework of the Brazilian-German INTECRAL project. Additionally, it explores the role of pastures as opportunity areas for climate change mitigation by enhancing the carbon storage capacity at landscape level. As the study is based on a scientific cooperation with the Rio de Janeiro State Secretary of Agriculture as implementation partner, it is expected that experiences presented in this paper will be useful to Brazilian stakeholders and decision makers for improving the adaption to exacerbating environmental conditions in rural areas, driven by climate change and inappropriate land use.

Developments and Opportunities for Ecosystem-Based Disaster Risk Reduction and Climate Change Adaptation

In the past few years, many advances in terms of research, implementation and policies have taken place around the world with respect to understanding, capturing and facilitating the uptake of ecosystem-based approaches for disaster risk reduction (DRR) and climate change adaptation (CCA). We highlight some of these advances here, particularly for coastal (various hazards), riverine (floods), and mountain (landslides) environments. We also highlight that many international agreements reached in 2015 can facilitate the uptake of these approaches whereas ecosystem-based solutions can facilitate the achievement of many goals and targets related to DRR, CCA, and/or sustainable development enclosed in these agreements. Finally, the chapter provides an overview of the rest of the book.