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School of Geography

Masters by Research Projects (Ecology and Global Change)

1. Understanding underground biomass in Japanese knotweed
Understanding the extent of the underground biomass and rhizome in the soil is crucial to managing invasive non-native species. Japanese knotweed (Fallopia japonica) is suspected to have a large rhizome network that remains viable in the soil long after herbicide treatment has ceased. This has led to the frequently cited 7 m rule being used as a reason to deny mortgage applications on properties with infestations. However, this distance is not based on experimentation and requires further investigation. Depending on student’s interests, the project could (i) use ground penetrating radar to determine the extent of the rhizome network across a range of soil types and stand maturities; (ii) investigate the rate at which Japanese knotweed rhizome extends using historical and current satellite imagery and site investigation across a range of habitat types; (iii) investigate the longevity of buried rhizome material using herbicide treatment, burial and exhumation experiments; (iv) calculate cell death rate microscopically over the period of the research project to determine half-life and to model longevity; (v) investigate the depth that rhizomes of the each species are found across a range of soil types and conditions for a range of distances from parent plants.
Supervisors: Dr Karen Bacon, Dr Mark Smith & Mark Fennell (Aecom)

2.  The impacts of preservation on leaf traits and leaf chemistry
The preservation of chemicals produced by leaves is an important biochemical marker that can be preserved in the fossil record. This project will focus on investigating the how leaf traits and leaf chemistry differ under different preservation conditions through field and laboratory experiments. The student will conduct a range of experiments in temperature cabinets and in the field and will determine which leaf traits and which chemical signals are preserved or lost though the processes of decomposition.
Supervisors: Karen Bacon and Fiona Gill

3. Assessing pixel-level uncertainty in land-cover classification
Many ecosystem models, including hydrological models, ecosystem services models and others, require a map of land cover. Often, such maps are produced based on supervised classification, namely a machine-learning algorithm e.g. random forest that uses a set of 'training' or validated data points. Methods to characterize the uncertainty of such algorithms at the pixel-level are scarce and often difficult to implement. This MbR project will explore a new metric to estimate this uncertainty for the case of random forest classifiers. A good level of GIS software experience is required, and experience using remote-sensing and machine-learning is preferable but not mandatory. The student will learn how to use Google Earth Engine and R for remote sensing analysis and statistical data analysis.
Supervisors: Guy Ziv

4. The Seasonal Phenology of Amazonian Forests
It has recently been shown that leaf demographic processes are important regulators of the seasonality of photosynthesis in Central and Eastern Amazonian. However, little is known of the seasonal patterns of leaf phenology in other Amazonian regions, which differ markedly in climate and forest dynamics. The southern Amazon is the driest region of the Amazon, characterised by a 5-6 month long dry season, and is known to be more limited by water than the Central Amazon. The western Amazon is characterised by higher productivity and higher turnover than the Central Amazon. This MRes project will focus on the analysis of multiple data streams from two Amazonian forest sites, both equipped with instrumented towers, to better understand the seasonality of leaf phenology in southern and western Amazonia. The first site is a transitional forest system located in Nova Xavantina, Mato Grosso, Brazil . This is a rapidly warming site located at the extreme dry fringe of the Brazilian Amazon. The second site is located in Tambopata, Peru, and represents a typical western Amazonian forest with high productivity and turnover. Both sites are equipped with a weather station and with an optical camera for monitoring crown phenology. The Nova Xavantina site is further equipped with a thermal camera for monitoring leaf temperatures, dendrometers for determination of the seasonality of growth, sap flow sensors and soil moisture sensors installed at an array of depths up to 3 m. The Tambopata site is further equipped with an eddy covariance system for determination of CO2 exchange between the forest and the atmosphere.
These multiple streams of data allow for a wide range of questions to be addressed. These may include:
1) How does canopy greenness vary seasonally in Nova Xavantina and Tambopata?
2) How variable is the seasonality of canopy greenness across individual species in each of the study plots?
3) What is the correlation between the seasonality of canopy greenness and the seasonality of stem growth?
This project will entail substantial amounts of image processing and statistical analysis. It is well suited for a student who enjoys programming and data analysis.
Supervisors: David Galbraith , Emanuel Gloor, Ben Hur Marimon Junior, Eric Cosio

5. Assessing plant blindness
Most people can identify the common animals of the UK but ask them about equally common plants and many will be stumped. This is called "plant blindness" and is a problem because plants are fundamental to our ecosystems, well being and food.  This project aims to investigate plant blindness in different groups (e.g. university students, school students, general public) and aims to determine if plant blindness is more or less pronounced in certain areas of the population and find out why. We also aim to develop ways of tackling plant blindness.
Supervisors: Julie Peacock and Karen Bacon

6. Ecological value of stately homes
Large stately homes and their accompanying gardens provide a unique ecosystem with characteristic flora, fauna and soil function. Across the UK the Historic House Association supports over 1600 historic homes and their associated gardens. These gardens are of huge ecological importance. Not only for the diverse plant species they support, both native, wild and cultivated species and hybrids, but also for their potential to store significant amounts of carbon in their soils. Many such homes are on the edge of urban environments and they can help mitigate human impacts through the ecosystem services they provide.
Working with Harewood House as the lead partner and also other estates within the Treasure Houses of England network, the student will have access to ideal locations to assess the impact of management practices on plant and soil function and their resilience to ongoing threats such as climate change and disease outbreaks.  We currently know nothing about how the introduction of non-native species and soil management of large gardens impacts on the main soil quality indicators, such as soil organic carbon (SOC) and soil pH of these estates. For example, are higher SOC stocks maintained under perennial woody bushes and trees, where soil may be less disturbed, compare to frequently dug ground used for herbaceous borders? By developing a database and accurate maps of plants, their traits and associated soil characteristics including soil organic carbon storage, total nitrogen, pH, C : N ratio and bulk density at Harewood and other Treasure Houses an understanding of carbon storage in these estates will become clear in addition to the impacts of the different vegetation and management practices.
An additional benefit of the study is that the true value of the unique flora of stately homes is unknown; with no complete record of species and hybrids easily accessible:  this study will start to provide those details. The Aichi Biodiversity Target 13 (2011), recognises the value of cultivated species, including those that have socio-economic or cultural value or species that are now rare in their native locations, making the estates living plant libraries. These plants have been collected from around the globe and many local hybrids have been developed.  The natural historical value of gardens at stately homes is as important as their art or the homes themselves, and they are interconnected with our social and cultural history but is far less comprehensively understood.
Supervisors: Julie Peacock and Karen Bacon

7. Analysing the water household of an Amazonian tropical forest in an increasingly hot environment
Warming of tropical land regions is widespread but its overall effect on tropical forest functioning is unclear. Increases in drier than usual conditions may likely exacerbate potential negative consequences of increased heat on remaining forests. One consequence of increased temperatures is an increase in the difference between water vapour in stomata and air, which is called water vapour deficit. This will cause water loss to increase unless stomatal opening is down-regulated. On the other hand evapotranspiration through stomata cools leaves thus posing conflicting needs under heat stress. How trees respond to these changing conditions and what effects it eventually will have on forest composition and productivity is unclear.
To study these questions we have established a forest stand monitoring site at Nova Xavantina, a site at the southern rim of the Amazon basin.  The Nova Xavantina site is particularly well suited to study heat effects because maximum daily temperatures are high and peak temperatures have increased rapidly over the past years. Between 2005 and 2014 (data from INMET, www.inmet.gov.br) they exceeded 40°C a total of 53 times. Xavantina is amongst the dry end of Amazonian forests, and generally experiences significant seasonal shortages in rainfall. Measurements related to water cycling of the forest include continuous recording of climate (precipitation, solar radiation and air temperature), soil water content at several soil depths, and sap flow for a selected set of trees. We also have characterized hydraulic properties of trees: hydraulic conductivities, stomatal conductance relation with vapour pressure deficit. Finally we continuously monitor canopy temperatures which will give some insight on evaporative cooling. The purpose of the project is to use these data and a model representation of water cycling in trees, describing the full soil tree air continuum, to analyse how trees modulate their water cycle. In essence the model represents tree soil water uptake and loss through canopy as a balance between evaporative pull air at the canopy on water filaments in tree water conducting cells against soil matric pullsoil, gravitational pull (see illustration) and resistance k of conducting cells to water transport. If the stress on filaments becomes too large they will rupture causing embolism and loss of water conductivity. Some components of the model are well established while other components, specifically the soil component, will need some development and evaluation work.

The project will aim to characterise (i) how water transport in trees is modulated under varying conditions and different trees using the continuously measured data, (ii) to what extent tree hydraulic properties combined with a soil water balance model and recently developed stomatal conductance models based on hydraulic state of trees agrees / disgress with data, (iii) what the data and modelling results tell us about about tree functioning under the currently rapidly warming climate. The student should have an interest in tropical forests, the use and application of data analysis tools like R or matlab and some skills and interest in programming and computer models.
Supervisors: Manuel Gloor, D. Galbraith, B. Marimon, J. Tavares, M. Johnson

8. Climate effects on tropical tree growth: light vs. drought limitations
Tropical forests are an important component of the global water and carbon cycles. Despite their importance very little is known on tropical tree responses to variation in climate. Specifically, it has been suggested that tropical tree productivity may be limited by water at drier sites and light at wetter sites, but few observational data exist. In this project you will use tree rings and isotopes to unravel the effects of drought and light limitations on tropical tree growth and photosynthesis. You will make use of existing tree ring samples from various different sites in the Amazon basin and Central America, and analyse ring width and carbon isotopes to understand growth responses to light and drought. The work involves an exciting combination of dendrochronology (tree ring analysis) and advanced state of the art isotope analysis.
Supervisor: Dr Roel Brienen

9. Why do hiatuses and spontaneous recoveries in peatlands occur?*
Rationale: There is much concern that peatlands will dry out under warming climate and switch from sinks to sources of carbon. Details: The student will carry out an analysis of existing data alongside computer modelling to examine the conditions under which peatlands have a net loss of peat. Spontaneous recovery of peatlands following disturbances will also be investigated. Methods: Literature-based data collection and numerical analysis/computer modelling.
Supervisor: Graeme Swindles

10. Testate amoebae as environmental indicators in natural and artificial peat pools*
Rationale: Methods for biomonitoring of natural and artificial peat pools are needed. Details: We will investigate the ecology of testate amoebae in natural and artificial peat pools and test their potential as environmental indicators. Methods: The project will involve fieldwork in N. England and laboratory analyses.
Supervisor: Graeme Swindles

 * indicates this project is not eligible for consideration for the EGC bursary.