There has been a recent recommendation to set restoration baselines as pre-degradation ecological communities. However this is a nostalgic aspiration, akin to restoring the ‘Garden of Eden’. It is unrealistic, expensive and does not acknowledge ecosystem change. Restoration should respond to the current drivers of biodiversity loss by addressing declines in ecosystem function and provisioning of ecosystem services.
Earth is in a land degradation crisis. Roughly a third of the world’s land is degraded, which is adversely impacting biodiversity and ecosystem function. If combined into one geopolitical boundary, these ‘Federated States of Degradia’ would have a landmass bigger than Russia and a population exceeding 3 billion, largely consisting of the world’s poorest and most marginalized people.
The extent and impact of land degradation has sparked many multilateral agreements with ambitious restoration targets. In 2011, the Partnership on Forest & Landscape Restoration proposed The Bonn Challenge – to restore 150 million ha of degraded land by 2020. This target was extended to 350 million ha by 2030 at the September 2014 UN Climate Summit. In January 2015, the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) proposed a thematic assessment of land degradation and restoration. At the December 2015 Paris Climate Conference, a further 100 million ha of restoration by 2030 was committed to – the African Restoration Initiative (AFR100).
These ambitious goals are essential to focus global effort on such significant challenges. Restoration projects tend to assess their success based either on simplistic input metrics (e.g. number trees planted, number of stems per hectare) or projects aim for outcomes that are difficult to quantify (e.g. improve ecosystem integrity). Using inputs as success proxies are risky as they may not reflect actual ecological success and ‘motherhood’ outcome statements are difficult to quantify and too complex.
There has been recent emphasis to set a reference baseline to guide restoration success (Kotiaho et al 2016). It has been recommended that restoration should aim to put back pre-degradation ecological communities. We suggest (Breed et al 2016) that this baseline is a nostalgic aspiration, akin to restoring the ‘Garden of Eden’, rather than an improved standard. Gearing restoration to emulate pre-degradation habitats is unrealistic, can be prohibitively expensive and does not acknowledge current and future environmental change. Instead of this ‘Garden of Eden’ baseline, we argue that restoration should respond to the current drivers of biodiversity loss by addressing declines in ecosystem function and concentrate on the provision of ecosystem services.
While a baseline that prescribes a list of pre-degradation species is a good place to start, it does not take into account the dynamism of ecological communities. Communities have always been and are constantly in flux, particularly during the Anthropocene. Species migrate, evolve and go extinct. Invasive species may be so prevalent and naturalised that they are impossibly costly to remove. Land allocated for restoration is often so altered from its pre-degradation state that it will no longer serve as habitat for the pre-degradation community. Many local, native species can be prohibitively difficult to propagate. Present-day climate change may necessitate the use of non-local genotypes and even non-local native species to improve restoration outcomes.
Newer, forward-thinking approaches may result in the generation of novel genepools or even novel ecosystems. Projects should focus on targets that are relevant to their overarching goals. For example, if a project has been established to improve pollination services then the abundance and diversity of insect pollinators could be their metric of success. As highlighted by Breed et al (2016), restoration should focus on building an ecological trajectory towards functional, self-sustaining ecosystems that are resilient to climate change and provide measurable ecosystem-service outcomes – as emphasized by IPBES.
Article by Martin Breed, Nick Gellie, Peter Mortimer, Andrew Lowe
From School of Biological Sciences and the Environment Institute, University of Adelaide, North Terrace, SA 5005, Australia; Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Heilongtan, Kunming 650201, Yunnan, China; and World Agroforestry Centre, East and Central Asia Regional Office, Kunming, 650201 Yunnan, China
Article re-edited from original published in The Conversation; https://theconversation.com/were-kidding-ourselves-if-we-think-we-can-reset-earths-damaged-ecosystems-59972
Breed MF, Mortimer P, Lowe AJ (2016) Biodiversity: ‘Eden’ baseline is unrealistic. Nature 534: 469.
Kotiaho JS, ten Brink B, Harris J (2016) Land use: A global baseline for ecosystem recovery. Nature 532: 37. doi:10.1038/532037c