Therfield Heath Conservation
New Year, Big Plans! Managing Succession in plant communities.
Happy New Year from the Conservators and staff at Therfield Heath. We have some big projects which we want to get underway on the Heath which will benefit Human and Wildlife alike. Scrub removal to save the rare grassland species will begin and below is some information to the why.
To understand how to manage plant communities we need to understand how they would behave without human intervention. In a land with no people, plant communities undergo a process called ‘succession’. This is where there is the plant community progresses directionally from bare rock to mature woodland. As plant matter dies, or is eaten and passed by animals, this enriches and deepens the soil layer, pushing the plant community further toward woodland. Every plant community would not, however, make it to woodland before being interrupted, and woodland would not be left undisturbed. Events like volcanic eruption, landslide, erosion, fire, and diseases all cause communities to regress. The natural pushing and pulling of these communities towards stable woodland creates a wonderful mosaic of habitats including bare rock, shallow soil, grassland, scrub, young woodland, and mature woodland.
However, people do exist, and we heavily influence our surroundings. If plant communities are left without natural or human intervention they will progress towards mature woodland, and important plant communities will disappear without being replaced elsewhere. On Therfield Heath natural grazers are largely excluded. Deer after all, rarely play golf or rugby. We replace this with domesticated grazers, which undertake a similar role, and provide a food source for people. Where sheep grazing is not possible, contractors will be cutting grassland across the Heath. The cuttings are collected so the nutrients do not enrich the soil and progress succession.
Understandably, people protect their surroundings from catastrophic events, and the Heath is no exception. To conserve vital chalk grassland, we must interrupt succession through management. This means allowing some erosion to bare chalk where possible, leaving some ground disturbance by animals such as the digging of burrows, and removing scrub where the richest chalk grassland is being lost. Keep an eye out for scrub removal across the site where our ranger and volunteers will be restoring sensitive areas to grassland, and ensuring this crucial habitat isn’t lost to succession.