The Basics of Brownfield Ecology

Photo by Guillaume de Germain on Unsplash

During your morning run or journey to work or university, you might have come across sealed-off, abandoned areas of land, often covered in litter, rubble or leftover construction material. While they may seem like patches of wasteland to us as passersby, these pockets of urban land are highly valued by environmentalists and ecologists. They are labelled brownfield sites. In this blog, I will explore the reasons for restoration of these sites and the processes that take place. Essentially, this blog will give you the basics of the whats, the hows and the shoulds of UK urban brownfield ecology!

What are brownfield sites?

Brownfield sites are defined differently depending on the area they are studied in, but the UK's definition is that these are lands first developed by surface infrastructure (such as housing or industry) that are then disused and recolonised by different ecology (Allen, 2014). In statistics, there are currently 100,000 brownfield sites in England - covering over 65,760 hectares - and over 4,000 sites in Scotland (Oliver et al., 2005). It's common to expect that brownfield areas wouldn't have much restoration or preservation value, but they surprisingly contain some unique ecology! UK brownfield sites are home to some of the most nationally rare species, such as the great crested newt, the slow worm, the common lizard and the black redstart. Redevelopment of brownfield sites for other uses would therefore mean these species would lose their habitats. This is why environmentalists and ecologists emphasise the importance of brownfield ecology to carry out restoration efforts for these habitats and wildlife species. 

What do you mean by 'restoration' and what are some of the other recovery methods?

In a literal sense, restoration is returning something to its original state. So in the context of brownfield sites, restoration means efforts to return the ecology to its pre-disturbance state. For example, imagine walking into a messy room and your task is to tidy it. Naturally, you would want to return everything to its rightful position - this is essentially what happens during brownfield restoration efforts. 

However, there are other recovery approaches that can be carried out on brownfield sites, as well as other 'degraded' sites, such as forest land after deforestation, contaminated rivers etc. The most common of these approaches is rehabilitation, in which the area's ecology is set back on its natural trajectory and then allowed to recover itself - in other words, partial restoration. This is more like partially tidying your room before allowing it to 'sort' itself out afterwards. Another common approach to brownfield land recovery is replacement/reclamation, in which brownfield ecology is transformed onto a different recovery trajectory. Analogically speaking, with this approach, you wouldn't restore your tidied room back to how it looked before, but instead you would change some - or all - of its layout. 

How do you recover the ecology of a brownfield site, and what are the challenges?

Still using the room-tidying analogy, the first step to recovery is essentially to determine what the room looked like before it became messy - in other words, the 'baseline' of the site. This is often no easy task as the site-specific factors (its history, chemistry, climate and ecology) all must be determined before recovery approaches can be finalised (Rotheram, 2017). One of the major challenges that recovery faces is the lack of monitoring after measures are put into place (Thompson et al., 1997). Monitoring would be similar to taking photos of your room to know how it should look after tidying up - lack of monitoring therefore means that you wouldn't really know if the room is correctly tidied up! Additionally, another problem faced here is that the baseline can change, so selecting a recovery timeline can be a challenge: do you tidy the room based on what it looked like one day ago, or one year ago?

The next step of recovering a brownfield site is to select the technical approaches to be used. Scientists debate which approaches may be best, something which often delays the recovery efforts. For instance, some promote the 'blanket approach' - which would be like tidying up five different rooms to make them all look the same, rather than adapting approaches and tidying the room as you see fit depending on the circumstances (Prentis and Norton, 1992). The technical approaches themselves are complex on top of these debates, and depend on the specific characteristics of each case (such as the funds, research and support available). On top of this, to complicate things further, recovery technique selection is also impacted by the stakeholders. Stakeholders such as the landowners may either accept whatever changes are suggested for recovery, or they may want the land to be used in a different, specific way, even if this may not be best for the land's ecology. This specificity is labelled as 'absolute geography' and can hugely limit brownfield recovery planning processes (Lorimer, 2008).

Once these recovery plans are finalised and agreed upon, the last step to brownfield recovery is then finally of course to carry out the plans and monitor the site to carefully identify any post-recovery issues that may crop up.

Should we recover brownfield sites in the UK?

So far, I have only really discussed the environmental value of brownfield sites when thinking about the future of these areas. It's also key to consider socio-economic and political aspects here, as well as the issue of sustainable development. For example, the UK's population is projected to grow from 62.3 million in 2010 to 73.2 million by 2035 (Allen, 2014). Considering this huge growth from a socio-economic lens would probably lead more in favour of brownfield redevelopment for infrastructure and housing purposes, as opposed to recovering the sites for ecological purposes. It's therefore important that a balance is struck between preserving the uniqueness of brownfield ecology and meeting political and social needs within the country. Individual action, resources and effort is what ultimately determines what is considered valuable in the future of brownfield sites: their unique habitats and species, the profit that can be made, or somewhere in between.

I hope you learned something new from this blog and are interested in finding out more about UK ecology! I've compiled some references if you are interested in further reading on this topic:

• Allen, J. (2014). 'Utilisation of analogous climate locations to produce resilient biodiversity plantings for infrastructure developments'.
• Bradshaw, A. D. (1984). 'Ecological principles and land reclamation practice', Landscape planning, 11(1), pp. 35-48.
• CPRE (2019). State of Brownfield 2019 An updated analysis on the potential of brownfield land for housing. Available at: https://www.london.gov.uk/sites/default/files/ad_114_state_of_brownfield_2019.pdf (Accessed: 15/03/2021).
• Evans, J. P. (2007). 'Wildlife corridors: An urban political ecology', Local Environment, 12(2), pp. 129-152.
• Lorimer, J. (2008). 'Living roofs and brownfield wildlife: towards a fluid biogeography of UK nature conservation', Environment and Planning A, 40(9), pp. 2042-2060.
• Megharaj, M. & Naidu, R. (2017). 'Soil and brownfield bioremediation', Microbial biotechnology, 10(5), pp. 1244-1249.
• Oliver, L., Ferber, U., Grimski, D., Millar, K. & Nathanail, P. (2005). The scale and nature of European brownfields.
• Prentis, E. & Norton, G. A. (1992). '“MEADOWS”—an expert system for the establishment of diverse wildflower grasslands on derelict land in urban areas in the UK', Ecological Engineering, 1(3), pp. 213-228.
• Raco, M. & Henderson, S. (2006). 'Sustainable urban planning and the brownfield development process in the United Kingdom: Lessons from the Thames Gateway', Local Environment, 11(5), pp. 499-513.
• Robins, J., Henshall, S. & Farr, A. (2013). 'The state of brownfields in the Thames Gateway', Buglife–The Invertebrate Conservation Trust, Peterborough.
• Rotherham, I. D. (2017). Recombinant ecology-a hybrid future? : Springer.
• Thompson, S., Treweek, J. R. & Thurling, D. (1997). 'The ecological component of environmental impact assessment: a critical review of British environmental statements', Journal of Environmental Planning and Management, 40(2), pp. 157-172.
• Thornton, G., Franz, M., Edwards, D., Pahlen, G. & Nathanail, P. (2007). 'The challenge of sustainability: incentives for brownfield regeneration in Europe', Environmental science & policy, 10(2), pp. 116-134.

Author: Jay

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