Grassland restoration
For many years, Northmoor Trust has been involved in researching ways of increasing the botanical diversity of grasslands.
In 1986, grazing trials were begun on Little Wittenham Nature Reserve. The plots on the hill were also used to study gap dynamics. In 1995, an experiment was set up on Hill Farm to investigate the effects of management on the spread of introduced species. Most recently, an experiment was begun in 1999 to see if a parasitic species could be used to increase the botanical diversity of fertile grassland.
Round Hill Grazing Trials, Little Wittenham Nature Reserve
Set up in 1986 by Jo Treweek of Oxford University, the experiment aimed to find appropriate grazing management that would achieve desirable botanical changes with out causing excessive damage to species already present and without loss of economic viability.
The plots have subsequently been used to investigate the nature and colonisation of vegetation gaps. This research has been lead by Jonathon Silvertown of Open University.
Many papers have been published as a result of work carried out at Little Wittenham, covering the ecology of the spear thistle Cirsium vulgare, competition, colonization, germination and seedling recruitment, and effects of grazing on colonization of species-poor grassland. The trial ended in 1998.
Hill Farm Slot-seeding Experiment
In 1995, an experiment was set up, in collaboration with the Centre for Ecology and Hydrology, to look at the best means of diversifying agriculturally improved grassland using restoration and management techniques. Twenty-two wildflower and grass species were slot-seeded into a species-poor grassland on the Trust's Hill Farm. Different management treatments were then applied to the grassland in a replicated random design (1. graze only, 2. cut July, 3. cut July and September, and 4. cut July and aftermath graze: full details can be found in Coulson et al. (2001). After six years the different treatments have resulted in markedly different botanical composition and vegetation structure. We hope to publish our findings shortly.
The experiment has also been used to study the mechanisms controlling spread away from sown slots, of two species; yellow rattle Rhinanthus minor and ox-eye daisy Leucanthemum vulgare; under different management treatments. The results indicated that dispersal was more important than seedling establishment in controlling spread of these species. Enhancing dispersal distances through management such as hay cutting is possible, but is only effective if timed to coincide with seed set. For more details see Coulson et al. (2001).
Church Meadow Rhinanthus minor Experiment
In 1999, an experiment looking at the potential for using yellow rattle Rhinanthus minor to promote botanical diversity of grassland was set up, in collaboration with the Centre for Ecology and Hydrology. Yellow rattle is a parasitic grassland plant, which takes nutrients from, and thereby reduces the vigour of other plants, especially competitive grasses that can dominate high nutrient grasslands. By reducing the growth of these grasses, yellow rattle allows other plants to establish in the sward. Plots on Church Meadow (part of Little Wittenham Nature Reserve) have been sown with varying amounts of yellow rattle. Typical grassland flowers that have been unable to spread onto the meadow naturally were sown a year later. If the experiment shows that yellow rattle is an effective tool for increasing grassland diversity, it could replace other expensive and impractical methods such as turf removal and continuous cropping.
For more information on our grassland research please contact us.
