Ecosystem Restoration: What it is and how to do it

As the United Nations Decade on Ecosystem Restoration launches this World Environment Day, we are reflecting on the full meaning of ecosystem restoration. In 2019, our science partners Prof. Dr. Robin Chazdon and Prof. Dr. Pedro Brancalion published an article in the Journal of Science in which they explored what it means to take social and ecological considerations into account when restoring forests. Here, we want to continue on their theme and share some insights on what it means to restore ecosystems more broadly.

First, let us take a step back and remember that an ecosystem is any local unit of interacting species, spanning from interconnections between tiny microorganisms in the soil to macroscopic creatures such as deer and grasses. An ecosystem can be a forest, but it can also be a productive grassland system, an agroforest, a coral reef, or a peatland swamp. IUCN recently identified 108 unique ecosystems on earth ranging from urban to rural and from managed to natural. Although most discussion in the press focuses on the potential of trees to absorb and store carbon from the atmosphere, many other ecosystems also play an important role in climate adaptation and mitigation. We need all types of healthy, functioning ecosystems to thrive on this planet.

But what does a healthy ecosystem look like? Traditionally, we define ecological restoration as: The process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed. Typically, we take this to mean that there is a pristine reference state to which we need to return the ecosystem. However, the United Nations (UN) Sustainable Development Goals (SDGs) call for restoration of marine, coastal, and terrestrial ecosystems that have been degraded to “protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss”. Here, ecological restoration encompasses many approaches related to sustainable ecosystem management, such as agroforestry and silvopastoral systems, biodynamic agriculture, urban reforestation, and more, and many potential end states.

There are many ways to restore an ecosystem and we can set different goals for recovery. We may aim for full recovery to that pristine reference state, so the restored system resembles an undisturbed, native ecosystem. However, for technical, social, environmental or financial reasons, we may need to aim for partial recovery, where the objective might be to help the system continue providing a specific social or environmental benefit or service, such as food or climate change mitigation. The Society for Ecological Restoration (SER) places these various efforts along a continuum that lead to various stages of ecosystem restoration.

Figure from Gann et al 2019

Regardless of what kind of project we are doing or what level of recovery we are seeking, when we want to restore a degraded ecosystem, we need to make a plan that includes considering who we might affect with our intervention. Regardless of our objectives, there are eight principles for ecosystem restoration that we need to consider:

• Engage all relevant local (or not) actors that affect and are affected by your project, be they rural farmers, local government agencies, or private corporations. Genuinely involving local people can lead to better long term outcomes.

• Consider and engage various knowledge systems when designing and planning the intervention. We need to acknowledge our own blind spots and respect the knowledge and insights of farmers, indigenous communities, and other local actors who live in or engage with the ecosystem.

• Be informed and learn about a reference, undisturbed or less disturbed, ecosystem near your project area. Restor’s species lists and general ecological data can help, but it’s always good to have a local reference point, when possible.

• Support natural ecosystem processes. We do not always need to actively plant species as a restorative intervention. Sometimes, just by protecting the degraded ecosystem from further degradation, such as by fencing off cattle or preventing fires, we give the ecosystem a chance to “heal” itself.

• Have clear goals and objectives measured via specific indicators. Monitoring restorative interventions is fundamental to advance our knowledge base on how to better foster ecosystem restoration, but can only achieve this if we have a good idea of what we are aiming for.

• Ecological restoration seeks to attain the highest possible level of ecological recovery. It is important to evaluate if and how to reach that end, or else be clear about intermediate goals or partial restoration goals.

• Some ecosystem processes can only be restored at large scale, such as watershed processes, in which case the planning of the restorative intervention is more complex, involving a multitude of stakeholders and the management at various scales, yet can achieve a multitude of ecological and social benefits.

• Restorative interventions can be seen as a continuum of actions towards the full recovery of the ecosystem if possible, such as depicted in the figure above.

These guidelines to ecosystem restoration can be our leading light through the decade of Ecosystem Restoration to keep us on the road towards achieving the multiple Sustainable Development Goals that ecosystem restoration can meet if conducted correctly. It may take time to reap the full benefits of our restorative actions today, yet there is no better time or place than to start today, big or small, but with our eyes looking forward into a future where we have learned to live in harmony with the rest of the natural world, a world where our actions don’t degrade, but restore.