Ecosystem Restoration

Protecting what remains is essential. Restoring what has been damaged is how landscapes regain the capacity to support life.

Environmental action has traditionally placed strong emphasis on protection: preventing further deforestation, conserving wetlands, safeguarding wildlife or setting aside protected areas. Protection remains essential, especially where ecosystems are intact or close to irreversible thresholds. But protection alone cannot recover the forests, rivers, soils and habitats that have already been degraded.

That is the role of ecosystem restoration.

The United Nations Decade on Ecosystem Restoration describes restoration as the process of halting and reversing degradation, leading to improved ecosystem services and recovered biodiversity. It encompasses a continuum of practices shaped by local conditions and societal choices. That wording is important. Restoration is not one activity, and it is not limited to recreating a pristine historical state.

It can involve removing the pressure causing damage, assisting natural recovery, actively reintroducing species, repairing hydrology, rebuilding soils or changing the way a productive landscape is managed.

The first step is often to stop the source of degradation. Replanting a riverbank has limited value if pollution continues upstream. Establishing seedlings on eroding land will not succeed if uncontrolled grazing, fire or insecure tenure remains unaddressed.

Restoration therefore begins with diagnosis: what has been lost, what is preventing recovery, which people depend on the ecosystem and what future condition is both ecologically credible and socially legitimate?

Some ecosystems recover when the pressure is removed. Natural regeneration can outperform planting because local seed banks, soils and ecological processes remain active. Where those capacities have been lost, however, active intervention may be needed. The method should follow the ecosystem, not the visibility of the activity.

Agriculture complicates the picture in useful ways. Many degraded landscapes are also places where people farm, graze animals, collect water or depend on forest products. Restoration cannot assume that human use will disappear. In working landscapes, success may mean recovering ecological function while sustaining production and livelihoods.

Agroforestry, riparian buffers, wetland rehabilitation, soil conservation and improved grazing management can all contribute when they are designed as part of a coherent landscape objective.

Sri Lanka's mangrove planting record shows how far activity can diverge from recovery. Kodikara and colleagues reviewed 23 restoration sites covering 67 planting efforts carried out after 2004. An estimated 1,000 to 1,200 hectares had been targeted, yet only about 200 to 220 hectares were judged successfully restored.

Inappropriate species, poor site selection and limited attention to hydrology meant that planting occurred without the conditions needed for a mangrove ecosystem to re-establish. The number of seedlings recorded the intervention; surviving, functioning habitat recorded the outcome.

Coffee and cocoa regions illustrate this continuum. A programme may protect remaining forest, encourage natural regeneration along waterways, diversify shade on farms, reconnect habitat fragments and stabilise degraded slopes. These actions are different in intensity but connected in purpose.

They seek to recover water regulation, habitat, soil function and resilience across the landscape rather than simply increase tree cover.

Tree planting is therefore not a synonym for restoration. The number of seedlings placed in the ground is an activity measure. Restoration concerns what survives, what functions return and whether the ecosystem becomes more self-sustaining. A plantation of one fast-growing species may increase canopy cover while providing little habitat, consuming scarce water or displacing local land uses.

Conversely, allowing natural vegetation to recover may look less dramatic in the first year but create stronger ecological outcomes over time.

Ecological recovery often takes longer than funding cycles. Survival in the first year does not show that habitat structure, species composition or ecosystem function will persist. Monitoring must therefore extend beyond delivery and adapt as the system changes.

Restoration also requires decisions about reference conditions. Climate change, altered species distributions and permanent land-use changes mean that returning exactly to a historical ecosystem may be impossible. A credible objective may instead focus on recovering native biodiversity, ecological integrity, connectivity and resilience under future conditions.

That requires science, local knowledge and humility about what can be reconstructed.

Rights and participation are central. Restoration can alter access to land, resources and livelihoods. Programmes imposed without secure tenure, fair participation or benefit sharing may create social harm and undermine ecological durability. People who live in and manage the landscape should help define what recovery means and how it will be maintained.

Ecosystem restoration is ultimately an investment in renewed capacity. It does not erase past damage, and it cannot substitute for protecting intact ecosystems. It does, however, recognise that degradation is not always permanent and that landscapes can recover when ecological processes and human institutions are supported together.

Practical application

A restoration programme should define the ecosystem, the degradation pressure, the desired functions and the people affected before selecting activities. For a sourcing landscape, this may involve mapping erosion, forest fragments and watercourses; identifying land rights and livelihood needs; prioritising areas where recovery can reconnect habitat or protect water; and agreeing how progress will be monitored.

A useful results chain separates implementation from recovery. Hectares enrolled, seedlings planted and farmers trained show what the programme did. Survival, native species return, reduced sediment, improved connectivity and stronger water regulation show whether the ecosystem is recovering. Both are needed, but they answer different questions.

Why it matters

Degraded ecosystems are less able to regulate water, retain soil, store carbon, support biodiversity or buffer communities from extreme weather. Restoration rebuilds these functions and can improve agricultural resilience, livelihoods and climate outcomes at the same time. It is one of the few sustainability strategies designed explicitly to reverse loss rather than only prevent more of it.

Common misconception

Ecosystem restoration is often equated with planting trees or returning a place exactly to its historical condition. Tree planting may contribute, but restoration is about recovered function and biodiversity. Historical reference points are valuable, yet future climate and social conditions may require an ecosystem that is faithful to ecological integrity without being an exact replica of the past.

Connections

Biodiversity describes the living variation and relationships restoration seeks to recover. Regenerative agriculture applies a similar ambition within productive systems, while landscape approaches coordinate recovery across farms, habitats and jurisdictions. Climate resilience improves when restored ecosystems regulate water, stabilise soils and provide more options for people and species.

A question worth asking

If a restoration programme reports hectares treated or trees planted, what evidence will demonstrate that ecological function, biodiversity and community benefits are actually recovering five, ten and twenty years later?

Selected references

- United Nations Environment Programme (UNEP). 2021. Becoming #GenerationRestoration.

- FAO, IUCN Commission on Ecosystem Management and Society for Ecological Restoration. 2021. Principles for Ecosystem Restoration.

- Kodikara, K. A. S. et al. 2017. Have Mangrove Restoration Projects Worked? An In-Depth Study in Sri Lanka. Restoration Ecology 25(5): 705-716.

- Gann, G. D. et al. 2019. International Principles and Standards for the Practice of Ecological Restoration. Restoration Ecology 27(S1): S1-S46.

- Holl, K. D. and Brancalion, P. H. S. 2020. Tree Planting Is Not a Simple Solution. Science 368: 580-581.