By Mariecia Fraser
Amongst the many excellent experimental resources at Pwllpeiran are a set of long-term plots known as the Brignant plots. They were created in 1994 as part of a MAFF-funded collaboration between the Institute of Grassland and Environmental Research (IGER) and ADAS, to test the effectiveness of different extensification managements in achieving reversion of improved permanent pasture to semi-natural vegetation. The plots were established on typical upland improved permanent pasture that had been ploughed and reseeded in the 1970s, and which had received regular inputs of fertiliser and lime. Project results indicated promising prospects for restoring species-rich grassland communities through natural species colonisation. They also indicated that different extensive managements could vary the rate and direction of successional changes. Funding for the original project work ceased in 2006.
When talking about what happened next, a colleague, Dr Gareth Griffiths, uses a fantastic analogy which compares experimental plots to cars. When they are new and shiny they attract lots of attention, but as time moves on they can start to look a bit dated as trends change. At this point there is a high risk of them being scrapped in favour of something newer. However, if they survive and are looked after they eventually start to gain value again due to their rarity and longevity. At this point the label switches to ‘vintage’. Thankfully, despite funding for the plots ending in 2006, the ADAS staff at Pwllpeiran kept the plots going on a ‘care-and-maintenance’ basis until they left; with treatments imposed but no data collected. Gareth Griffiths and others took over the cause until the lease of Pwllpeiran to IBERS was settled. Today the age and the extent of the treatments effects at the site make Brignant a unique experimental resource. It is one of only a handful of long-term ecological experiments in the UK, and the only one based on upland improved pasture. Grassland science owes a great deal to the staff that kept the resource going through ten turbulent years when its future was constantly under threat.
To give a bit of detail on the set-up, the plots are arranged in a randomized block design with three blocks and a total of seven grassland management regimes imposed on individual plots. The treatments are: sheep grazing, hay cut only, and hay cut with aftermath grazing; each with and without the addition of lime. Plots are 0.15 ha (grazed) or 0.08 ha (hay cut only) in size. Control plots continuing the previous site management (i.e. limed, fertilised and continually grazed by sheep) are also included within each block.
Although over two decades old, the plots are highly relevant to today’s knowledge and evidence gaps. A third of the upland grassland in the UK is categorised as improved permanent pasture, and for the majority of farms within less favoured areas the extent and condition of these swards determines the overall level of productivity possible. However, the policy framework for permanent grasslands is currently undergoing major change due to BREXIT/CAP reform plus reinterpretation of their role in terms of environmental regulations. These changes can curtail the management options available to farmers, and there is much debate amongst policymakers and the industry as to the wider implications of the new rules. New project work is quantifying for the first time the impact of the alternative management treatments on a broad suite of provisioning, regulating and supporting ecosystem services, and explore related above and below ground processes. Collectively the results will be used to deliver a comprehensive comparative assessment of productive performance and public goods delivery from permanent pastures under alternative management regimes.
This year marks the 160th anniversary of the Park Grass experiment at Rothamsted Research, despite its future being highly uncertain at times. Justifiably, this and similar very long-term trials at Rothamsted are referred to as the Classical Experiments, and their contribution to science celebrated. Brignant is one of only a handful of UK sites that can aspire to be a Modern Classic.