In 2020, the Trust purchased its first rewilding site, Little Duxmore Farm on the Isle of Wight. The land purchase was funded through the sale of nitrate credits. Little Duxmore was an arable farm that was receiving high amounts of fertiliser inputs. By taking on the ownership and management of the 17-hectare farm, and taking the land out of intensive arable production, we were able to provide mitigation for planned housing developments through the sale of nitrate credits. Environmental credits are emerging as a new way to invest in nature’s recovery and tackle the nature and climate emergency through nature-based solutions. The Trust’s nutrient reduction programme at Little Duxmore was one of the first in the Solent. Our aims were to rewild the site, reduce nutrient pollution through the cessation of nutrient inputs, and secure the land for wildlife in perpetuity. We worked with the local authorities and statutory agencies to develop a scheme that satisfied the necessary legal requirements for nutrient mitigation and set a gold standard for similar nature-based solutions programmes.

Little Duxmore Farm sits on a tributary of the Wootton Creek, which means it can offset the impact of new developments in the Portsmouth, Havant, Fareham, and Gosport areas, which once occupied, will drain into water treatment works at Budds Farm and Peel Common. We screen all developments we provide credits to according to our ethical principles.

What we’ve achieved

Two years on, we have sold nearly all of the available credits from the site. Unlike other schemes, we are aiming for an overall nutrient reduction, rather than just neutrality, therefore we keep back 5% of the available credits.

Through the process of arable reversion, we have achieved a wilder landscape, with more space for nature. Our ecological surveys have recorded a wide range of species utilising the site, including farmland birds, a multitude of invertebrates, rare arable flora, and much more. We will continue to monitor species abundance and diversity as the site transitions.

Rewilding

We are taking a minimal management approach, with rewilding. In order to create a wilder landscape we will be grazing at low densities using belted Galloway cattle and Exmoor ponies. We will also be using pigs carefully in some priority areas for arable flora. Native grazing animals act as ecosystem engineers. These large herbivores create areas of bare ground and tear at vegetation as they graze, creating variations in sward structure and habitat niches for invertebrates. Pigs are ‘agents of change’ because they like to turn over the turf and soil with their snouts. The opening up of the soil and turning over the turf, in a controlled, gentle way, creates small micro-habitats which provide new opportunities for plants such as arable weeds to grow.

Our aims are for greater bioabundance i.e. much more wildlife as well as more biodiversity. The composition of species and plant communities will change as the site develops into a mosaic of different habitats at different stages of succession.

What about the nitrates?

Our water nutrient testing showed an increase in nitrate and phosphate content between the source of a stream and the point at which the stream exits the site, indicating that nutrients are indeed leaching into the water from the fields at Little Duxmore from its previous land use. Soil testing has also shown high levels of nutrients. We are therefore monitoring the soils and water on the site and will be recording how the nutrient content reduces over time, ensuring it is in line with the nutrient reduction calculations, from which the nitrate credits have been generated.

What’s Next

Ecological monitoring at  Little Duxmore began in April 2021. We have been monitoring birds, bats, butterflies, bumblebees, and Orthoptera on a monthly basis, as well as setting up trail cameras, testing soil and water nutrient levels, and sampling earthworm populations across the site.

Ecological surveys will continue annually to monitor changes in species numbers and diversity as the site develops. We have also been testing nutrient levels in the soil and stream to provide a baseline, which will allow us to track any reductions in nitrate and phosphate levels over the coming years.

Fencing and cattle grids will be installed this summer, in preparation for the native ponies and cattle arriving to graze the site. The site will be grazed as a whole, creating areas of wood pasture, scrubby mosaics, and some downland restoration. We are also going to do some gentle ground disturbance in the priority areas for arable flora, under expert guidance, to generate suitable conditions for these species to thrive. We are also looking to try and establish some wet flushes and dew ponds to further enhance the site for biodiversity.