Priory Grazing Project

10 Things You Need to Know About the PRIORY GRAZING PROJECT

1 The Priory Grazing project has been initiated as part of the school’s sustainability program. The project is intended to support the school’s efforts at “Healthy Habitats”–for wildlife and people.

2 2019 marks the second year of the grazing project. In 2018, the school hosted 240 goats and cleared two acres of land. This year, we had 800 sheep grazing 12 acres in total.

3 Sheep are grazers; goats are browsers. While goats will eat just about anything that they can reach or climb to–from grass and shrubs, to bark, leaves, and overhead branches–sheep prefer to feast on grass forage. The school’s grassy hillside is a perfect pasture for sheep. The sheep the Priory hosted are called ‘white dorpers’.

4 Humans, grazing animals, and the plants they eat are part of an ancient interdependent ecological relationship. Throughout our evolutionary history, nomadic humans have followed large herds of hooved animals on their annual migrations. These animals, in turn, would follow moving belts of rain–and the plants that grew in their wake. Some humans hunted the animals; others worked to domesticate them.

5 Grazing animals live together in herds–which is good for the landscape. The social aspect of clumping provides these animals protection from predators in wide-open spaces. The high population densities of herding animals cause them to urinate, defecate, and walk on the plants that they eat. These activities promote the proper decomposition processes in the upper layers of soils and help with nutrient recycling.

6 Humans have changed the population sizes and migratory routes of grazing animals. Our modern farms, cities, and roads have all impacted the numbers of hooved grazers on the landscape, as well as the extent of the predators that might hunt these animals. As a result, the ecology and nutrient cycling of modern grasslands is fundamentally different than it has been throughout evolutionary time.

7 Plants can use photosynthetic energy in three different ways: for biomass growth, for reproduction, and for pest protection. Usually, plants are effective at two of these strategies. Grasses don’t grow tall or store lots of carbon as wood, but they do produce large numbers of seeds after a short growing season, and each blade’s serrated edges makes it nearly impossible to digest for most herbivores.

8 We can see adaptations among animals like sheep, goats, cows, and other hoofed grazers that are evolutionary responses to the grass’ reproduction and pest-defense strategies. Chunky molars, leathery tongues, stomachs with multiple cavities, and non-stop chomping show what is needed to make grass work as a food resource. And, in the same way that sheep have evolved to eat blades of grass, they are also able to tolerate sharp and spiny thistle, which grows as an annoying invasive species on the hill.

9 The grazing project aims to replicate natural systems. The tight clumping of the 800 sheep encourages the animals to graze pretty hard in the areas in which they are enclosed. They will eat the grass– and thistle– to within 2-4 inches of the soil. Meanwhile, the animals will be trampling the areas that they have eaten and leaving dung and urine behind. These simple activities create contact between vegetative litter and the soil surface. This promotes soil bacteria decomposition processes–to a far greater extent than had the grass grown and died, full-stature, as it would have done had the sheep not been here. As a result, the soils should retain more carbon and more water than if the area was ungrazed. This means they will stay greener longer into the summer, and we should see less thistle (Bull thistle, Italian thistle, and Yellow Star thistle). Additionally, this will improve pest-control opportunities for local predators (hawks, herons, owls).

10 We hope that the Priory Grazing Project demonstrates that some solutions can be integrated and interconnected. The project is principally organized to improve soil health and control invasive species. But wait, there’s more. Just as the grassland soils should retain more carbon and water, and stay greener longer, this should also provide some measure of fire-prevention. And to the extent that we can avoid mowing the grasses, we are reducing the impact of heavy machinery on the hillside. Additionally, the carbon that is trapped by the soils is carbon that is not released to the atmosphere as CO2. For this reason, ‘silvopasture’ (a selective, intensive grazing project like this, but on a global scale) is seen as one of the top 10 things humans can do to draw-down atmospheric CO2 levels for climate impact.