Syllabus Edition
First teaching 2024
First exams 2026
Rewilding (DP IB Environmental Systems & Societies (ESS))
Revision Note
Written by: Alistair Marjot
Reviewed by: Bridgette Barrett
Rewilding
Human activities such as deforestation and overharvesting of resources can disrupt, damage and destabilise ecosystems
Conservation efforts at the ecosystem level aim to restore ecosystem stability by restoring natural ecosystem processes
These processes may include:
Predator-prey relationships
Seed dispersal
Nutrient cycling
This type of ecosystem restoration project is also known as rewilding
Restoration strategies may involve:
Species reintroduction
Reintroduction of apex predators will reduce herbivore populations and allow the restoration of habitat vegetation
This may boost the diversity of plant species
This, in turn, enhances total biodiversity
For example, wolves were reintroduced to Yellowstone National Park, USA
The wolves help to control deer populations
This has allowed certain types of vegetation to recover
Reintroducing keystone species can improve the structure of an ecosystem
For example, beavers have been reintroduced to parts of the UK
Beavers build dams
These dams create large wetland areas that support diverse wildlife
Improving habitat connectivity
This involves connecting fragmented habitats to allow free movement of species
Creating wildlife corridors, such as hedgerows on farmland, connects small pockets of habitat
This allows wildlife to roam over larger areas, increasing the resources available
This allows larger population sizes to establish
Stopping agriculture
Allowing land previously used for farming to return to its natural state
For example, the Knepp Estate in England has been rewilded
This former farmland now supports wild ponies, pigs and longhorn cattle
These species promote biodiversity by disturbing soils, dispersing seeds and grazing on vegetation, so no single plant species dominates
Limiting human influence
This may involve preventing the harvesting of resources, e.g. by logging or fishing
Ecological management techniques, e.g. controlled grazing or burning, may be used to restore a habitat
The aim is to minimise direct human management and let ecosystems self-regulate as much as possible
Case Study
Restoration of Hinewai Reserve, New Zealand
Location: Banks Peninsula, New Zealand
Hinewai Reserve was once farmland but is now privately owned, with the aim of restoring the natural ecosystem of the area
Some initial human intervention was involved, e.g. the removal of non-native species
The area is now managed with minimal human intervention to allow native communities to be restored by succession
Human activities are limited in the area, though the public can enjoy walking in the Reserve
Successes:
Rapid regrowth of native bush
Increase in native bird populations
Effective control of invasive species
Examiner Tips and Tricks
Make sure you understand and can define key terms like rewilding, apex predators, keystone species, and habitat connectivity. You should also learn one or two examples of successful rewilding projects
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