Richard Sharp and Rob Free from ARC’s field teams explain how we use conservation grazing as part of our habitat management work and some of the important aspects which must be taken into account before using this long-standing method. 

The British Isles has a long history of human intervention and management, including grazing, leading to a high proportion of semi- natural open habitats, semi-natural meaning a wild habitat with some management from humans needed to maintain it in its present state. chalk downland and heathland are the two most notable habitats that fall into this category. Due to that history of human land use these habitats can be exceedingly rare, as measured by area, on a global scale.

Grazing has always played a part in the management of our wild spaces. From the free roaming herds of large herbivores in a post glacial landscape, through the start of light touch interventions by Mesolithic people clearing glades and managing the landscape to make hunting game easier, to the gradual intensification of livestock production from the Neolithic to the present day.

Now grazing is part of a suite of tools available to a land manager to look after these open habitats. Like many other concepts in modern conservation and ecology, vague notions and ideas have coalesced over the last 30 years into a more cohesive approach we call "conservation grazing". Using hardier and/or rare breeds of livestock, in an extensive manner (small numbers of animals over a large area) to mimic wild herbivores or previous less intensive agricultural use.

Reptiles and amphibians thrive in these open habitats and for the rarer species, such as smooth snake and natterjack toad, they are dependent on them in the British Isles. A mosaic or mix of habitat elements such as differing sward heights of grasses and heather or varying densities of scrub trees can help with the complicated ecology of these species. Ecologies that are driven by the need to thermoregulate, reptiles and amphibians cannot control their own body temperatures, well-structured open habitats can provide the ecological niches needed to warm up, cool down and for the amphibians retain body moisture. Especially as we move north and the suns power declines this structure becomes increasingly more important and reptiles more constrained to good quality habitat with south facing aspects.

It is a tricky balancing act to manage semi natural open habitats, all most certainly with competing and conflicting species interests and needs. Grazing can be a useful tool in maintaining these habitats especially at the micro habitat level providing a variety of habitat elements and ecological niches, to much or to little intervention can tip a site either way into a non-favourable condition.

ARC has tried to navigate the various controversies and issues surrounding conservation grazing on reptile and amphibian sites, giving guidance in our Habitat Management Handbooks and publishing a position statement on the issue in 2013. Suggesting that in habitats with a high potential for reptiles such as lowland heathland a cautious approach should be taken in managing a site or reserve with grazing livestock. The Position Statement highlighted several factors that could adversely effect reptiles and amphibians under a Conservation Grazing regime;

  • If a site is small or isolated the poor dispersal attributes of reptiles and amphibians will make repopulation nigh on impossible.
  • High stocking densities or a long time period can flatten the all important habitat structure leaving fewer places for reptiles to live
  • Grazing can be targeted at habitat elements that are good for reptiles and amphibians, such as beds of Molinia grass, but perhaps mistakenly, thought to be in need of intensive management

Many conservation schemes have very vague conservation objectives making management difficult, how do you know when to put livestock on or off? How do you know when the desired outcome is reached? How do you measure adverse effects on non-target species?

All of the above can be avoided by putting in careful thought at the start of a conservation grazing project and indeed perhaps having the ability to say “the risk is too high, perhaps we can use a different method”. There are great examples of reptile and amphibian friendly grazing schemes using methods such as Holistic Grazing and well planned compartments (fenced areas) and timing of the grazing season. There will always be competition between the importance of species or habitats on a site and the choices about what needs conservation intervention will always effect other species, it is what we do to mitigate these effects that will show the success of any management option we choose.

On ARC’s Dorset reserves a proportion are under a grazing regime for the general management of heathland, the regime is designed to be as reptile friendly as possible while still achieving habitat elements for wild flowers and invertebrates. The objectives are vague, as the outcomes are, but the timing is reduced to autumn, avoiding the main time periods of reptile activity and livestock numbers are low, enough to reduce vegetation but maintain structure while helping increase the diversity of flowering plants.

At the other end of the spectrum we have our work for natterjack toads and pool frogs, nationally rare species that have very precise habitat needs. Natterjack toads hunt by running after their invertebrate prey and prefer a very short turf, they also burrow and need access to areas of loose soil. All of these elements can be provided by intense grazing, reducing and breaking up the vegetation sward. However there are still further interventions needed by humans to create and maintain ponds, and clear scrub trees from our reserves. Obviously such intense grazing will affect other reptile and amphibian species and we have to think very carefully about how we manage the livestock to maintain suitable habitat for all species. At the end of 2022 ARC partnered with another conservation charity, The Moorland Mousie Trust, to resume grazing at the natterjack toad reserve at Sellafield in Cumbria. This use of rare breed ponies to manage vegetation has been so far very successful.

As rewilding becomes more and more part of modern conservation we must look to see how a move to using more naturalistic methods, and grazing’s part in that process, may affect our native reptiles and amphibians. Recently ARC colleagues wrote an article on this topic looking at how the main aspects, including grazing, might affect reptiles and amphibians. The idea of reproducing fully functioning ecosystems at landscapes scales, including grazing and keystone species such as beaver and larger predators is possible but difficult with the nature of landownership and distribution in the British Isles. Though the principles can be incorporated into any sites management now, the nature of many of our smaller reserves and the ecological needs of reptiles and amphibians as species there will be a need for management interventions by humans for some time to come. As with the more traditional approaches to conservation grazing and site management we can see that a nuanced approach to rewilding with allowance for management interventions will always be needed for sites and landscapes of importance for reptiles and amphibians. 

Britain is an island of semi natural open habitats favoured by reptiles and amphibians, Conservation Grazing is a valid management tool for these habitats and can benefit reptile and amphibian species. But as with all things there is a balance to be maintained and a careful nuanced approach to the management decisions we make as land managers is needed. Weighing up the needs of different species and habitats and mitigating for the effects of the choices we make. Knowing what we have and carefully planning where we want to go so that we can monitor the outcomes and take action when needed.