Mr Nana Akwasi Osei
PhD student
Location: Room 224, Geography Buildingemail: n.osei@qmul.ac.uk
Phone: 020 7882 4868
School of Geography
Queen Mary, University of London
Mile End Road, London E1 4NS
PhD Research Title: Riparian large wood: structure and function in fluvial systems
Background
The structure and dynamics of large wood in river systems, together with its influence on hydrogeomorphology and ecology, has received considerable interest over the past three decades. Much of this research has focused on the characteristics of wood in the channels of single thread river systems. Although disturbances such as floods and gales induce the storage of large quantities of wood across the margins of river channels into the riparian zone, the importance of this marginal wood has been considered only recently.
In particular, knowledge of the importance of this marginal wood for processes such as sediment and organic matter retention, seed bank development, and vegetation colonisation is negligible. The relative fragmentation and limitation of knowledge and understanding of large wood structure and induced processes characteristic to large wood within the lateral dimension in rivers of different ‘styles’, sizes and climates, postulates research to advance a holistic understanding of river-floodplain systems.
This research is concerned with the structure and functions of large wood in the riparian margins of river systems, exploring some knowledge gaps in large wood research and will contribute to our understanding of the role of large wood in landform development and vegetation colonisation in riparian zones.
Key words: large wood, riparian, seed bank, vegetation
Highland Water, Single-thread: Classic complete large wood jam
Aim
This project aims to focus on large wood in the riparian zones of headwater and floodplain reaches of rivers of different ‘style’ and climatic regions and to explore wood quantities and accumulation types retained in these riparian zones and their importance in structuring riparian geomorphology and plant ecology.
Research Objectives
- To undertake inventories and construct typologies of wood accumulation types impinging on or present within the riparian zone.
- To evaluate the geomorphological alterations driven by large wood in river reaches.
- To investigate mesohabitat diversity in and around complex large wood jams.
- To investigate the dependence of the plant community on large wood within riparian zones in river styles through studies in seed bank and / or colonising vegetation structure.
- To explore the relevance of these processes (ii, iii, and iv) to river restoration and recovery
Tagliamento River, Multi-thread: Large wood jam with associated mesohabitats in the floodplain reaches
Methods
As riparian zones are dynamic ecotones whose geomorphological and ecological characteristics may be expected to vary with river size, position and climate along the river continuum, an extensive field and laboratory work involving geomorphological and mesohabitat mapping, wood accumulation surveys, seed bank sampling and germination trials will be conducted on rivers of different ‘styles’ in the UK (single-thread) and Italy (multi-thread).
The intention is to combine these methods to comprehend the relationship between wood quantities and accumulation types, geomorphological processes and vegetation colonisation in the riparian zones of headwater, middle and lower reaches in single and multi-thread river systems under different levels of large wood management.
Expected Outcome
River Bure, Single-thread: Reintroduced wood jam colonised by vegetation in summer 2011
The exploration of this research area will improve our understanding of the structure and the role (geomorphological and ecological (vegetative)) of large wood in river margins, and riparian landform and habitat development across different river ‘styles’, sizes and climates. This will potentially underpin the development of systematic riparian management and river restoration - rehabilitation efforts using large wood which is useful for the cross-disciplinary fields of river and catchment management.
Supervisors
Professor Angela Gurnell and Dr. Gemma Harvey
Funding
Queen Mary, University of London Studentship
Academic Background
MSc Catchment Dynamics and Management, University of Leeds, United Kingdom
BSc (Hons) Natural Resources Management, Kwame Nkrumah University of Science and Technology, Ghana