Category 3: Forest ecosystems and ecosystem services – Københavns Universitet

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Category 3: Forest ecosystems and ecosystem services

CATEGORY 3 RESEARCH TOPICS:

3.1     Does beekeeping alleviate poverty? Productive conservation in less-developed countries

3.2     Biodiverse cocoa plantations contribution to nutrition and ecosystem services

3.3     Understanding the role of root, mycorrhizal and microbial turnover in forest ecosystems

3.4     Ecosystem services of apex predators  

3.5     Tipping points in mangrove ecosystem function

3.6     Combining modelling approaches of multiple spatial scales for the assessment forest ecosystem services at mesoscale watersheds

3.7     Linking soil carbon sequestration in forests with hydrological ecosystem services

3.8     Interaction of cyclone disturbance and biological invasion impacts on the long-term ecological dynamics of tropical montane and temperate forests

3.9     Assessing structural and functional landscape connectivity for multi-species corridor design   

3.10   A reappraisal of the role of trees on greenhouse gas fluxes from tropical forests

3.11   Effects of climatic extremes on carbon and water cycle in various land-use types

3.12   Trees for food and climate: optimal management of tree by-products for plant and soil and carbon conservation and restoration

3.13  Adaptation and vulnerability of woody species used in traditional agroforestry in tropical areas

3.14   Invasive Acacia species in Africa what is their real impact on the environment and people

3.15   Textural parameters for linking soil, canopy and satellite images

3.16   Forest biodiversity characterization and monitoring with very high resolution remote sensing images, new approach through image texture analysis

3.17   Alien woody communities: their management and effects on biodiversity

3.18   Landscape restoration harnessing multifunctional landscapes to sustain livelihoods?

3.19   What serves climate change mitigation in the short and long term best - Storage of biomass in the system, or substitution by harvested biomass?

3.1 Does beekeeping alleviate poverty? Productive conservation in less-developed countries
Rural income generating activities continue to be promoted as a means to easing poverty levels and contributing towards meeting Millennium Development Goals. One such activity is beekeeping, which is frequently cited as a suitable development vector for both poverty alleviation and forest conservation in less-developed countries. Numerous beekeeping development programmes have been initiated but despite several apparent successes, many programmes appear not to have effectively addressed poverty alleviation or contributed to forest conservation. The sustainable success of such programmes appears to be contingent upon drivers such as training and information, access to credit, policy-related support, and market access. The aim of this project is to evaluate the relative effectiveness of beekeeping in less-developed countries to reduce poverty levels and to determine the influence of the activity on forest conservation. Using case studies the impacts of beekeeping on household well-being and forest conservation will be investigated. A number of methods might be considered to address the research questions at a range of scales (household, wider community and bee-keeping programmes) using a combination of household surveys, national well-being data sets, choice-based methods and GIS. The project outcome will contribute robust, peer-reviewed analysis to international development organisations, of the relative effectiveness of beekeeping programmes to both alleviate poverty and conserve forests.
Principal supervisor at Bangor University
Co-supervisor at University of Copenhagen

3.2 Biodiverse cocoa plantations contribution to nutrition and ecosystem services
Wild forest foods are rich sources of macro- (carbohydrates, lipids and proteins) and micro-nutrients (vitamins and minerals), as well as dietary fibre and other important phytochemicals, but many species are in decline in anthropogenic landscapes which fragment forest habitats. This parallels problems of malnutrition and vitamins and iron deficiencies associated with impoverished diets. Smallholder cocoa production systems are the major mode of cocoa production globally, and these biodiverse systems can be a rich source of nutrients to help cope with the hunger gap, alleviate food insecurity and provide ecosystem services. The proposed research will take a whole system study looking at aspects of health, nutrition, shade in diverse cocoa agroforestry systems; and consider the role of selected germplasm in resilience and climate adaptation, particularly relevant in shaded agro-ecosystems.
Principal supervisor at Bangor University
Co-supervisors at Bangor University and University of Copenhagen

3.3 Understanding the role of root, mycorrhizal and microbial turnover in forest ecosystems
Forests are known to be a major sink for atmospheric carbon. Although we now a lot about how carbon is sequestered above ground in the tree canopy, our knowledge of carbon cycling below ground remains poor. The aim of this PhD is therefore to determine the major inputs of C belowground in a range of forest ecosystems and to understand the processes that regulate these C flows. Key research questions are: which is more important in locking up C in soil, mycorrhizas, root turnover, root exudation or microbial turnover? How does forest type regulate the amount of carbon storage? How will climate change affect these C flows? The PhD will involve fieldwork in a range of deciduous and coniferous forests in the UK and Germany. The work will use the latest isotope technology to monitor the flow of C through the plant-soil-microbial system. The student will gain experience in monitoring of greenhouse gases, isotope tracking, basic modelling, carbon budgeting alongside field and laboratory analysis. It is expected that the research will lead to a major shift in our understanding of below ground nutrient flow in forest ecosystems.
Principal supervisor at Bangor University
Co-supervisor at University of Göttingen

3.4 Ecosystem services of apex predators
Apex predators are critical to ecosystem function through the range of services they are thought to provide. Issues such as prey limitation and mesopredator suppression have been well documented, however there are a range of other critical ecosystem services that apex predators perform that have not been documented as thoroughly. These include waste disposal through carcass decomposition and prey spatial avoidance behaviour. As apex predators are in direct competition with humans, our expanding population has resulted in an increasing extinction risk for apex predators. Therefore these functions may soon be lost. The often localised nature of apex predator distribution (particularly when coupled with conservation fencing) provides an opportunity to experimentally investigate the ecosystem services provided by apex predators. Key research questions are: how does the presence/absence of apex predators affect these ecosystem services. There are a range of potential study sites with a suitable design to investigate this issue from almost all continents and a range of countries.
Principal supervisor at Bangor University
Co-supervisor at University of Göttingen

3.5 Tipping points in mangrove ecosystem function
Mangroves are among the most productive forest ecosystems. More importantly to local people, they provide an array of ecosystem services: coastal protection and fisheries nursery habit; pollution amelioration; fuel and timber provision. Overexploitation and land conversion means that globally, mangrove cover has reduced by one third in recent years. Mangrove ecosystems are resilient to a degree of stress, moving reversibly down a degradation gradient, whereby if the driver of stress is mitigated, the system recovers. However, if stressors continue acting beyond a tipping point, the hostile near-shore environment means that function is lost, recovery is impossible, and restoration difficult. This project aims to identify and characterize such tipping points, which might be ecological, hydrological, sociological, or a combination of these, e.g.: Loss of canopy cover à altered energy balance à hypersaline soils; Loss of near surface biomass à increasing wave energy à no regeneration; Aquaculture ponds à high nutrient loads à soil eutrophication. Key research questions are: (i) What are the indicators of degrading mangrove function? (ii) What are the tipping points beyond which mangrove function is lost irreparably? (iii) What options exist to mitigate drivers becoming stressors? (iv) What restoration interventions can return lost mangrove?
Principal supervisor: Bangor University
Co-supervisor at University of Göttingen

3.6 Combining modelling approaches of multiple spatial scales for the assessment forest ecosystem services at mesoscale watersheds
Watershed-scale models like the Soil and Water Assessment Tool (SWAT) are useful tools for Integrated Water Resources Management (IWRM). They help to evaluate the contribution of contrasting land-use types to the provision of hydrological ecosystem services (HES). Thus the models may assist local stakeholders to frame land-use policies. However, the application of watershed-scale models is constrained by the availability and quality of data for model input and validation. Traditionally, forests have been considered as source for timber, which resulted in a rough representation in watershed models without spatial validation. Since the focus of forest management has changed to the additional provision of HES, aim of the study is to find a method how tools like BROOK 90 or CoupModel (plot scale) can be usefully combined with watershed models (SWAT) in order to achieve a better spatial representation of forests in catchment modelling. In this study a watershed (500 1500 km²) will be analysed. In one step the plot-scale models will be calibrated for intensively monitored plots (e.g. LEVEL-II stations in Europe). Afterwards the results will be regionalized for all forest stands in the study catchment. Finally the spatial results are used to validate the watershed scale model.
Principal supervisor at Dresden University of Technology
Co-supervisor at University of Padova

3.7 Linking soil carbon sequestration in forests with hydrological ecosystem services
Forests in watersheds are beneficial in the water cycle. Many of the water-related ecosystem services (e.g. flood retention, water quality) are related to soil properties, notably the amount, quality and vertical distribution of organic matter in the soil. Deforestation and forest degradation typically lead to reduction of soil organic matter. Beside aboveground biomass REDD+ (Reducing Emissions from Deforestation and Forest Degradation) also intends to consider belowground carbon stocks including those in soils. However, there is only scarce information on changes in soil carbon following changes in land-use, but results from the analysis of false chronosequences may be instrumental. Here, time elapsed after land-use has changed (e.g. from natural forest to plantation or agriculture) is substituted by the comparison of adjacent plots of contrasting land use. The proposed PhD study will systematically evaluate the literature for such data and assess the relevance for soil functioning in the hydrological cycle. The information is implemented in hydrological models to quantify effects on water-related ecosystem services. Plot-scale models may be used as a basis to implement watershed models (i.e. SWAT) for testing land management options in relation to carbon sequestration at the landscape scale. Additionally hydrological models could also be coupled with carbon models.
Principal supervisor at Technische Universität Dresden
Co-supervisors at Bangor University

3.8 Interaction of cyclone disturbance and biological invasion impacts on the long-term ecological dynamics of tropical montane and temperate forests
Models of climate change predict increased frequency of severe storm events and increased vulnerability of natural forests to invasion. A major research question is how this interaction causes long-term impacts on forests through ecosystem, community and population dynamics. Our network of forest permanent sample plots (PSPs) provides an outstanding research opportunity because of their long monitoring duration and location in sensitive island tropical montane and European Atlantic ecosystems. In the Jamaican Blue Mountains (hurricane-prone global biodiversity hotspot), three sets of experimental PSPs date from 1985 monitoring invasion by the Australian tree Pittosporum undulatum. Similarly two sets of PSPs from 1996 are in Coed Dolgarrog, the largest forest nature reserve in Wales, with frequent gap formation and increasing domination by invasive Fagus sylvatica. The project involves re-enumeration of these PSPs, with new measurements of tree allometry using a lightweight unmanned aerial vehicle (octocopter), shade and soil N cycling. Modelling tree community dynamics will determine processes by which invasion X disturbance alters light- and N-availability; community structure and productivity, its partitioning amongst species; leading to threshold versus linear change. This will be important for understanding mechanisms maintaining forest biodiversity, and for adaptation of forest conservation management to climate change.
Principal supervisor at Dresden University of Technology
Co-supervisor at Bangor University

3.9 Assessing structural and functional landscape connectivity for multi-species corridor design
Landscape connectivity is important for avoiding species extinctions and for maintaining ecosystem functions. While structural landscape connectivity is relatively easy to quantify in a GIS, understanding functional landscape connectivity from the perspective of species requires an understanding of the behavioural response of individuals to landscape characteristics. In this project, we aim to use a multi-species simulation approach to compare models of structural versus functional landscape connectivity (the exact study area will be finalized in discussion with the student). We will use GIS data to first model structural landscape connectivity for the area, and then parameterize individual-based simulations to model landscape influences on realized movement and gene flow (potentially validating our models with genetic data). Key research aims are to: (i) develop a GIS database for quantifying landscape attributes (i.e., fences, land cover, etc.) that will likely affect movement and gene flow in selected wildlife species; (ii) use individual-based simulations to assess how landscape complexity likely influences movement and gene flow in the different species; (iii) compare the resulting landscape models to identify corridor areas that are particularly important for maintaining functional landscape connectivity for multiple wildlife species in the study area.
Principal supervisor at University of Göttingen
Co-supervisor at Bangor University

3.10 A reappraisal of the role of trees on greenhouse gas fluxes from tropical forests
Globally, tropical forest soils are the largest natural source of the greenhouse gas (GHG) nitrous oxide (N2O), and tropical forest wetlands are an important source of methane (CH4). Recent studies based on bottom up calculations (extrapolation of measured/modelled soil-atmosphere flux data) have reduced estimates of the CH4 and N2O source strength of humid tropical forests soils which is in contrast to top-down approaches (using atmospheric trace gas concentrations combined with inverse modelling) which continue to point at the humid tropical forest as important N2O and CH4 sources. For CH4, tree-mediated fluxes have been suggested as one of the reasons for this discrepancy, while for N2O some evidence suggests that root exudates may stimulate N2O emissions resulting in higher fluxes in close proximity to trees. The main research question is whether a reappraisal of the role of trees in greenhouse gas fluxes may explain the discrepancy between bottom-up and top-down estimates of the source strength of tropics forest soils and wetlands. Methods employed will be a combination of field measurements (chamber techniques and gas chromatography) laboratory work and modelling.
Principal supervisor at University of Göttingen
Co- supervisor at Bangor University

3.11 Effects of climatic extremes on carbon and water cycle in various land-use types
Land ecosystems play an important role in the global climate system as they can mitigate the effects of anthropogenic climate change by acting as sinks for greenhouse gases and are thus considered in the Kyoto protocol and the UN-REDD program. Climatic extreme events such as droughts, precipitation excess or late frosts have increased in intensity and frequency recently, yet their effects on ecosystems are not fully understood. Based on eddy covariance flux measurements at sites contributing to the global FLUXNET database, the project aims at assessing how carbon dioxide, water vapour, energy fluxes, and surface reflectance respond to various climatic extreme events. Various land-use types, e.g. managed or unmanaged forest or agricultural land will be investigated using local field measurements and multi-year data analysis with the global FLUXNET database and/or modelling. Knowledge of forest/environmental sciences, experience with meteorological measurements as well as good statistical skills is required. Key research aims are to: (i) identify ecosystem responses to climatic extreme events at selected sites, (ii) assess the response of multiple land-use types at regional/global scale using data from the FLUXNET database, (iii) investigate ecosystem recovery after climatic extreme events in dependence of ecosystem structure, diversity and/or management.
Principal supervisor at University of Göttingen
Co-supervisor at Bangor University

3.12 Trees for food and climate: optimal management of tree by-products for plant and soil and carbon conservation and restoration
Trees and forests build highly fertile and carbon-rich subsoils on which the productivity of agroforestry systems relies. Soils represent the largest terrestrial organic carbon pool. Their degradation and related loss of soil carbon, as well as exogenous inputs in agriculture, contribute to global climatic change. Woody amendments raise increasing interest for their agricultural and environmental potentials, including the multiple benefits of carbon accretion in soil. However, there is currently a lack of knowledge of the impacts or benefits that such applications will create in terms of ecosystem functioning across ecozones. Key research questions will evaluate the potential of woody amendments across a degradation and climatic gradient, to determine: (1) What is the reversibility of soil productivity decline with a variety of different tree by-products? (2) How do such practices fit in land-use systems or restoration activities? (3) What are the full environmental footprints of these practices?
Principal supervisor at AgroParisTech
Co-supervisors at Bangor University and AgroParisTech

3.13 Adaptation and vulnerability of woody species used in traditional agroforestry in tropical areas
Through agroforestry, deforestation and land clearing in tropical regions promotes the selection of useful tree species that provide ecosystem services or/and that have value for local stakeholders or commercial value. Expansion of the practise in recent decades justifies characterizing the functional adaptive traits of selected woody species that are still almost unknown. This knowledge would provide bases to evaluate the viability of selected trees under projected climate changes, and their impacts on resources. The study will quantify tree water requirements (transpiration) and processes involved in their water loss regulation in field conditions of an area with contrasted seasons. Sap flow, leaf water potential, stomatal conductance, leaf phenology and root dynamics will be analysed in relation to meteorological parameters, variations in water table depth and soil resources and flows (water, carbon, nutrients). Furthermore, as complementary in laboratory, the project will address anatomical traits of the trees that are related to hydraulics. Key research questions include: what is the proportion of rainfall which is transpired by the trees? How does soil fertility impact it? Does tree functioning indicate possible hydraulic lift? How do processes involved in the tree water regulation work? What are the tree limits facing an extreme drought?
Principal supervisor at AgroParisTech
Co-supervisor at University of Padova

3.14 Invasive Acacia species in Africa what is their real impact on the environment and people?
Invasions by non-native tree species are being reported ever more frequently. However, assessment of their environmental and livelihood impacts is restricted by lack of a suitable comparator, especially for invasions associated with habitat disturbance and where invasive and non-invasive species are taxonomically unrelated. Many native African tree species are also expanding their ranges into new habitats. The genus Acacia provides an excellent system to advance knowledge about key questions: (i) what traits make a tree species invasive; (ii) why can non-native species out-compete native species; (iii) what are the additional impacts of habitat invasion by non-native species versus equivalent native species? Most areas of Africa, from dry to moist climates, host native and introduced non-native Acacia species. Both groups contain a mixture of species that have become invasive and those that have not, giving a 2x2 matrix for structured comparison between related species of: morphological and phenological traits, and impacts on biodiversity, ecosystem hydrological or nutrient-cycling functions and services, and local livelihoods. This project requires field-work in one/more African countries using skills in forest/vegetation ecology, and gives scope for students to apply interests in: analyses of species distributions (GIS-based); traits; biodiversity; local perceptions and/or livelihood impacts.
Principal supervisor at AgroParisTech
Co-supervisor at Bangor University

3.15 Textural parameters for linking soil, canopy and satellite images
Assessment of soil properties like salinity, carbon, etc. is of major importance for calibrating global models. In mangrove areas, interactions between soil level and vegetation cover are strong. The cover is not as high as in the tropical forests, so the impact of canopy changes on soil properties is significant. Linking ground field data and remote sensing data is a major challenge on the way of up-scaling ground field knowledge. Despite the good local understanding of phenomenons and fluxes driving the ecosystem, it is always difficult to upscale this knowledge: (i) Is there a link between textural parameter on very high resolution image and some soil properties? (ii) Which textural parameters are the more suitable for canopy monitoring? (iii) Is there a link between hemispherical photos acquired from the ground and some textural parameter on very high resolution image (satellite like Pléiades or Ikonos). We propose here to collect field data along the same degradation gradient already observed, and to map the dynamic of changes on a larger scale, based on textural parameters. The candidate should have a good knowledge in spatial statistics and image analysis, and also a good practice of GIS / Remote Sensing software.
Principal supervisor at AgroParisTech
Co-supervisor at Bangor University

3.16 Forest biodiversity characterization and monitoring with very high resolution remote sensing images, new approach through image texture analysis
Forest biodiversity is a key factor in the equilibrium between nature and mankind. It gives access to fundamental resources and provides widely recognized ecoservices. Biodiversity is also a good marker of forest ecosystems status and of sustainable environmental practices. Nowadays forest biodiversity is threatened by fragmentation and loss of habitats, unsustainable use of natural resources, climate change, invasive species, etc. Therefore an accurate description and a regular monitoring of forests biodiversity are required. There is a great need of evolution maps and trends knowledge at a large scale. Forest study plots currently provide accurate and updated field data on biodiversity (e.g. species, densities, individual measurements). However, todays climate change issues require a wider-scale diagnosis, impossible to do manually. Remote sensing data are used with advanced image processing methods. (i) What is the link between canopy very high resolution images and observed biodiversity? (ii) Which textural features are the more suitable for biodiversity description? (iii) Stereo / tri-stereo in Biodiversity understanding? Additional field data will be collected according to the satellite images and to the seasons. The candidate should have a good knowledge in spatial statistics and image analysis, and also a good practice of GIS / Remote Sensing software.
Principal supervisor at AgroParisTech
Co-supervisor at University of Göttingen

3.17 Alien woody communities: their management and effects on biodiversity
622 woody species are currently recognized as invasive alien species and woody plant invasions are rapidly increasing in importance throughout the world, with important implications for forest and non-forest products, land reclamation and scenic beauty. However, many aspects of their invasion ecology are still unknown and demand insights into comparisons of their performance in different parts of the world. Moreover, the abandonment of former agricultural and industrial areas has recently increased the portion of lands suitable for invasion in Europe. The interaction between climate change and invasive species could further accelerate the degradation of ecosystems. Therefore, there is a great need to deepen the understanding of the effects of alien tree communities and of their management, on biodiversity. The student working in this project will conduct research to evaluate the rate of expansion of one or more alien tree species, chosen accordingly to the regions under comparison, their management alternatives, quantify the diversity of biotic components, and evaluate the influence of alien tree communities on biodiversity as related to the invaded native communities throughout Europe. These results will be of great importance to scientists interested in the intersection of biodiversity, land use and climate change and management in temperate ecosystems.
Principal supervisor at University of Padova
Co-supervisor at University of Göttingen

3.18 Landscape restoration harnessing multifunctional landscapes to sustain livelihoods?
Restoring productivity and provision of other ecosystem services (ES) manifested at landscape scales are key requirement in much of Sub-Saharan Africa to improve food security, cope with climate variability and enhance livelihoods, including through energy and fibre sold to urban populations. Agricultural intensification has often been associated with deforestation and deteriorating ES provision. However, including more trees in field, farm and landscape niches is a promising approach to reverse this and create sustainable multifunctional landscapes. Scientific evaluation of such landscapes is not well developed, particularly in seasonally dry environments. Key research questions arise around potential trade-offs and synergies amongst benefits from multifunctional landscapes: higher production and productivity, carbon sequestration and improved water management. The objective of this PhD project is to collect primary data on production, carbon storage, water flow and quality, in relation to tree cover and to apply the Polyscape ES model and negotiation support toolkit for multifunctional landscapes (developed at Bangor University). The research will be focused in NW Kenya where SLU, Jomo Kenyatta University of Agriculture and Technology and ICRAF are main partners in evaluating contrasting areas where enclosures and rotational livestock grazing have transformed the landscape, with more trees and improved livelihoods.
Principal supervisor at Swedish University of Agricultural Science
Co-supervisors at Bangor University and Jomo Kenyatta University of Agriculture and Technology

3.19 What serves climate change mitigation in the short and long term best - Storage of biomass in the system, or substitution by harvested biomass?
In forest ecosystems, large amounts of carbon are stored in living and dead biomass and in soil organic matter. Forests also have a high capacity for sequestration of carbon dioxide from the atmosphere via photosynthesis into biomass which, when harvested, may be used for substitution of fossil fuel energy and other greenhouse-gas emitting materials, including being stored in long-lasting products. This can be renewable if the forest biomass re-grows and has a positive effect in climate change mitigation. However, there is a trade-off between these mechanisms. Forest management designed to maximize the sustainable production of harvested biomass, for example through planting of fast-growing monocultures, use of fertiliser, whole-tree and stump harvesting, is likely to reduce net ecosystem carbon storage. This dilemma is currently of major global interest, and it is heavily discussed which strategies will serve climate change mitigation best. Furthermore, the delivery of other valued services such as biodiversity conservation and water surplus and quality will be influenced following conversion of natural forests to e.g. short rotation energy plantations. The aim of the project is to evaluate the mechanisms by which alternative forest management systems influence short- and long-term ecosystem carbon storage and sequestration rate.
Principal supervisor at Swedish University of Agricultural Sciences
Co-supervisor at University of Copenhagen