Key features of ideal mosaic habitat:
• A dynamic mosaic of disturbed ground, species-rich grassland, scrub and trees with a savannah-like appearance.
• It should have an average tree and scrub canopy cover of between 10% & 30% across the site. The closer to 20% the better.
• The height and density of both the scrub and grassland should vary across the site. The more structural variety, the better.
• Open areas and areas of low trees and scrub should be retained where possible by locating any taller trees (over 4 metres) close to existing trees and woodland. This is important for species of open farmland, particularly birds.
• Mosaic habitat is great for wildlife at any scale but the bigger the better. Ideally it should be created in blocks big enough for natural processes to create variety.
• Cotswolds mosaic habitat should be managed to maintain this variety whilst
The Need
Throughout 2021 a working group of the Cotswolds Nature Recovery Forum along with many partners developed the Cotswolds Nature Recovery Plan. One of the key outcomes which I didn’t expect, was an emphasis on the importance of new, ideally large, and lightly grazed areas containing a species-rich mosaic of grassland, scrub and trees. These large tracts of habitat will form new core areas, an essential component of the nature recovery network. Such areas are rich in the wide variety of niches (ecological “homes”) and edge habitats.
This approach has already been taken in a number upland landscapes such as Wild Ennerdale (4,800 Ha) and famously at a lowland location at the Knepp Estate (1,416 Ha) on the heavy clay of the Weald in Sussex. The potential for this approach within the substantially more species rich calcareous (chalk and limestone) landscapes is tremendous. Oxfordshire is of course lucky to have in part, three of these landscapes with the Cotswolds, North Wessex Downs and Chilterns National Landscapes.
There are already large areas of existing mosaic habitat on calcareous soils across southern England, not least Salisbury Plain (20,000 Ha). There are other sites that may not be of the same scale but are still considerable such as Cleeve Common (400 Ha) in the Cotswolds. Existing sites are rich in valuable ancient habitat and are consequently managed with care in a traditional manner. There is currently no example of large scale new extensively grazed mosaic habitat where natural processes are allowed to take place on calcareous soils
Management
Ongoing management would ideally be through extensive (light) grazing with native breeds. Cattle and ponies in combination are best as they simulate the grazing pressure that our wildlife originally developed in adaptation to.
Fenceless grazing with Global Positioning System (GPS) collars are an ideal way to manage them. These collars allow for internal areas to be excluded from grazing. Tree and scrub planting can be protected without internal fencing and further areas can be selected to develop into longer grassland and scrub with trees through natural succession.
An establishment phase would give an initial boost in terms of species richness. Following ground preparation such as harrowing, areas could be overseeding with locally sourced wildflower grassland seed. The Glorious Cotswold Grasslands programme has a well-established track record of delivering this work.
Physical Modifications for Priority Species
Mosaic is about having the whole variety of habitats from bare earth and short turf through to longer grass, scrub and trees. Many of our most endangered species require bare or disturbed ground. Until recently conservationists have undervalued the importance of disturbance. Subject to checks for archaeology, early physical interventions such as scrapes and pits in habitat creation sites could further enhance the areas species richness.
Ecosystem Services
New areas of mosaic deliver many benefits beyond providing core areas for wildlife. They collect and store water in the aquifer, they collect and store carbon, produce food in the form of high-quality meat, and support the health and wellbeing of those visiting. Years of research have led me to conclude that calcareous grasslands are the finest place on the planet to lay on your back in the sunshine and watch butterflies flutter overhead.
Adaptation to Climate Change
Mosaic habitat is also more resilient to the increasingly frequent drought events occurring as a result of climate change. Research has shown that calcareous wildflowers reduce or cease nectar production as an adaptation to drought. This means that during drought events calcareous flora a may look wonderful but from an invertebrate’s perspective the cupboard is bare. Mosaic habitat provides partial shade increasing the likelihood of nectar production in drought conditions. Partial shade is also important for the welfare of livestock.
Paying for it all
This type of varied habitat is beautiful, and full of wildlife. Its similarity to a savannah type landscape offers engagement opportunities for the visitor economy, including camping, glamping, and safari tours.
As it contains both woody material and legumes, mosaic is terrific for capturing and storing carbon although we have yet to fully understand the numbers and effectively turn this into income. Discussions concerning a grasslands carbon code have started.
Only last week Defra announced vastly improved payments for the creation and management of wildflower grasslands including, for the first time a payment for mosaic.
What to do?
A few things spring immediately to mind.
1. Let’s make sure that the emerging new Oxfordshire Local Nature Recovery Strategy strongly features new mosaic habitat.
2. Think about the structural diversity of existing habitat, though we should be cautious and wary of unintended consequences when dealing with our last few precious fragments of the “old stuff”.
3. When planning habitat creation and restoration don’t think grasslands or woodlands, get messy, mix them up, get creative!
Simon Smith C.Env M.C.I.E.E.M - Nature Recovery Lead - Cotswolds National Landscape
