Dr Chris Cockel
Teaching/Research Assistant
Location: Geography Building Room 202email: c.p.cockel@qmul.ac.uk
Phone: 020 7882 2777
Research Interests
Non-native and invasive plants of urban rivers, including dynamics, impacts, control, and implications for river restoration schemes.
My PhD (Alien and native plants of urban river corridors: a study of riparian plant propagule dynamics along the river Brent, Greater London) investigated the characteristics and dynamics of riparian soil seed banks and vegetation along urban river margins, with an emphasis on the impacts of invasive species on native communities, and the implications of this for river restoration and rehabilitation. The research was focused on the River Brent in West London and took Impatiens glandulifera (Himalayan Balsam) as a model for invasive alien species.
The River Brent is typical of urban rivers, where development has transformed catchment hydrological processes and adversely affected river water and sediment quality, and has also degraded the potential for ecosystem services. Urban river corridors present a complex mix of channel modification and reinforcement, with river margin environments often being highly disturbed, nutrient-enriched, and particularly susceptible to invasions by alien species. The process of restoration and rehabilitation poses many as yet unexplored questions regarding the process of alien species colonisation and distribution, as well as questions regarding the broader socio-economic implications of such schemes.
My research was conducted at a range of scales throughout the River Brent catchment and investigated the structure and composition of riparian vegetation communities, and the dynamics of propagule production, dispersal, and deposition, including the formation of soil seed banks. A suite of laboratory-based germination studies, and the testing of a range of alien species management techniques were employed with the aim of guiding management and policy decisions.
Research Findings
One of the key questions in looking at an urban riparian seed bank was, “Does an urban riparian seed bank contain a larger proportion of alien/non-native species than a rural seed bank?” In comparing my results with those from earlier studies conducted using similar sampling designs on three rural rivers, I was able to generate the following graph. This clearly reveals that while a rural seed bank may contain up to 5% alien species, the proportion of alien species represented in the riparian soil seed bank from the urban River Brent is over 20%. However, of these alien plants, only 18% appear in the standing vegetation within the river corridor.
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| Average number of alien species expressed as a percentage of the average total number of species identified on sites along the Rivers Brent, Dove, Frome and Tern. | Physalis peruviana - Cape Gooseberry germinated in the lab | Flower and fruit of Physalis peruviana |
This suspicious individual was recently spotted outside the police station in Brentford, which supports the bird seed origin.
One species that appears in the seed bank and has been recorded from the standing vegetation is Physalis peruviana – Cape Gooseberry.
A perennial native to high altitude South America, extracts of the plant have been widely employed for their medicinal properties. The small orange fruits can also be used for making jam, juice, sauces, chutney, ice cream, and eaten fresh in salads and fruit cocktail. Seeds of P. peruviana have also been found in imported bird seed. While not currently an obviously invasive species in the UK, P. peruviana is listed as invasive in India and on many islands in the Pacific. Given its ability to produce an abundance of viable seeds, coupled with milder winters in the UK, further research is needed to assess the invasive potential of this and other non-native species found in the soil seed bank.
Publications:
- Cockel C. P. & Gurnell A. M. (2011) An investigation of the composition of the urban riparian soil propagule bank along the River Brent, Greater London, UK, in comparison with previous propagule bank studies in rural areas. Urban Ecosystems. Online.
- Cockel C. & Tanner R. (2011) Impatiens glandulifera Royle (Himalayan Balsam) In: A Handbook of Global Freshwater Invasive Species (ed. R. A. Francis). Earthscan.
Conference Presentations and Posters:
- Cockel C. P. (2011) Invasive Plant Research on the River Brent, London. In: London Invasive Species Initiative Conference - Invasive Non-native Species in London, Natural History Museum, London.
- Cockel C. P. & Gurnell A. M. (2010) An investigation of the riparian soil propagule bank of the River Brent, London, UK, highlighting the proportion of alien species compared with similar studies in rural areas. In: 6th Neobiota Conference - Biological Invasions in a Changing World from Science to Management (eds. J. Kollmann, T. van Mölken & H. P. Ravn). Department of Agriculture & Ecology, University of Copenhagen.
- Cockel C. P. & Gurnell A. M. (2010) Plant propagule dynamics within urban riparian zones, highlighting the occurrence of non-native species along the River Brent, London. In: RGS-IBG Annual Conference, London.
- Cockel C. P. & Gurnell A. M. (2010) Plant propagule dynamics within urban riparian zones, highlighting the occurrence of non-native species along the River Brent, London, UK. In: British Ecological Society Annual Conference, Leeds.
- Cockel C. P. (2009) What lies beneath? Propagule banks of urban riparian zones – a study of the River Brent, West London. (poster) Research Postgraduate Conference, University of Hong Kong.
Other Projects:
Volunteers’ Coordinator - Environment Trust for Richmond-Upon-Thames
http://www.environmenttrust.co.uk/
Volunteer River Brent Catchment Officer – Thames Rivers Restoration Trust (TRRT)
Recording Invasive Species Counts (RISC) in association with the Botanical Society of the British Isles (BSBI)
Invasive Species Ireland (ISI) in association with the Department of Biological Sciences, Queen’s University Belfast
Royal Botanic Gardens, Kew, Sampled Red List Index Project (SRLI)
Conserving Europe's Threatened Plants, Botanic Gardens Conservation International (BGCI)