Ecological Restoration

Ecological restoration is the process of assisting the recovery of a degraded ecosystem so that its biodiversity, ecological functions and capacity for self-renewal are restored. It seeks a functioning, resilient ecosystem suited to the site, rather than merely increasing vegetation or tree cover. Tree plantation is only one possible restoration tool and cannot by itself recreate an ecosystem.

Core ecological principles

Restoration must address the causes of degradation and work with natural ecological processes rather than impose a uniform vegetation target.

• The target should reflect the site's appropriate ecosystem type, remaining biodiversity, physical conditions and a suitable reference ecosystem.
• Recovery depends on interactions among vegetation, soil, water, nutrient cycling, wildlife and processes such as succession and regeneration.
• Protection of remnant vegetation, seed banks and nearby source populations can enable natural regeneration and reduce intervention.
• Monitoring biodiversity, soil condition, habitat structure and ecosystem functions permits adaptive management when recovery diverges from objectives.

Restoring degraded grasslands

Grasslands are dynamic ecosystems maintained by climate, soils, herbivory and, in many systems, ecologically appropriate fire. Successful restoration therefore rebuilds their characteristic processes and structural diversity.

• The first priority is to reduce pressures such as excessive grazing, altered drainage, soil erosion, invasive species and inappropriate conversion or tree planting.
• Management should restore a suitable disturbance regime, including the timing and intensity of grazing and fire where ecologically appropriate, without allowing repeated disturbance to prevent recovery.
• Natural recovery from surviving grasses and soil seed banks should be preferred where feasible; otherwise, locally suitable native grasses and forbs may be reintroduced.
• Restoration should retain habitat heterogeneity and landscape connectivity so that grassland fauna can feed, breed, disperse and recolonise.

Forest restoration and the limits of planting

Forest restoration similarly begins by controlling repeated fire, excessive grazing, felling and other pressures. Methods depend on past land use, site condition and surviving sources of regeneration.

• Measures may include soil and moisture conservation, drainage restoration, invasive-species control, assisted natural regeneration and mixed native planting.
• Mixed planting can aid severely degraded sites lacking seed sources, but single-species, even-aged plantations may remain production-oriented systems.
• Monocultures or unsuitable exotic species may provide timber, biomass or canopy cover without restoring native species composition and ecological functions.
• Planting trees in naturally non-forest ecosystems can damage their characteristic biodiversity; higher tree density alone is not evidence of ecological recovery.