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Native ecosystems – climate superheroes

Native ecosystems – climate superheroes

Image: Steve Attwood, Nina Valley

Native ecosystems – climate superheroes

“Healthy and functional ecosystems help reduce climate change vulnerability and disaster risk by:

  • Reducing physical exposure to hazards by serving as protective barriers or buffers and so mitigating hazard impacts, including in wetlands, forests and coastal ecosystems; and
  • Reducing socioeconomic vulnerability to hazard impacts: sustain human livelihoods and provide essential goods such as food, fibre, medicines and construction materials, which strengthen people’s resilience to disasters.” Convention on Biological Diversity

“Restoring a third of the areas most degraded by humans and preserving remaining natural ecosystems would prevent 70% of projected extinctions of mammals, birds and amphibians. It would also sequester around 465 gigatonnes of CO2—almost half of the total atmospheric CO2 increase since the Industrial Revolution.”   Strassburg et al, 2020.

The problems

The Canterbury Regional Biodiversity Strategy (2008) aims for ‘no further loss of significant habitats and ecosystems…’ And yet, land clearing, primarily for agriculture, continues to destroy our native forests at a staggering rate. New Zealand has lost 13,000 hectares of native habitat in just the last five years (Fig. 1), exposing us to multiple threats including lost critical life-supporting ecosystem services and release of carbon dioxide from soils into the atmosphere.

Most natural ecosystems also store carbon through soils and the formation of peat, however, this is ignored under the current Emissions Trading Scheme (ETS).

Between 2012 and 2018, New Zealand indigenous land cover area decreased by 12,869 hectares (NZ Stats). Most natural ecosystems also store carbon through soils and the formation of peat, however, this is ignored under the current Emissions Trading Scheme (ETS). The 2021 Climate Commission report (09 June) acknowledges that the current ETS incentives plantation forests over new native forests.

Fig. 1: Fig. 1: Between 1991-2018 some 40,800ha of native forests, scrub and shrubands were lost. Other ecosystems have suffered equally widespread losses, including indigenous grasslands, which lost 44,800 ha. (p47 DOC1) (Image: DOC/Christie)

The solutions: protect, restore, rebuild

Nature-based solutions can be most effective when planned for longevity and not narrowly focussed on rapid carbon sequestration.” IPCC-IPBES  June 2021

Using an ecosystems-based adaptation (scroll down), let’s consider the key options:

Protect what’s left is the most cost-effective in terms of dollars, labour (voluntary and paid), biodiversity, and cultural outcomes. This immediately prevents more CO2 from entering the atmosphere, acts as a shock absorber against climate change, and provides ongoing life-supporting ecosystem services.

Restore those that are damaged: Depending on the scale, this is more expensive and takes longer. In the short-to-mid term, however, this will helps reduce the impacts of flooding and rising sea levels, heatwaves and wildfires, loss of ecosystem services and ability to grow or harvest wild food, and draw CO2 from the atmosphere.

Rebuild what’s been lost is costlier and takes longer. But because we’ve destroyed so much, once we begin to rebuild them, some will draw far greater volumes of CO2 from the atmosphere, reduce the impacts of unavoidable climate change, and provide long-term ecosystem services.

Incentivise the protection and restoration of native ecosystems under the Emissions Trading Scheme.

Disincentivise through economic mechanisms (primarily the ETS) the conversion of land currently used for other purposes (such as plantation forestry after harvesting) into uses other than restoring native ecosystems.

Make policies more robust so that non-compliance with land clearing rules can be readily prosecuted.

Strategies

It can take decades to centuries to reinstate natural forests, but there are cost-effective and proven strategies to achieve this by encouraging regeneration along the borders of existing pockets of native forests.

Reinstating ‘wet’ ecosystems including dune systems, saltwater marshes, seagrasses, kelp forests, rivers and wetlands is faster, and newly restored wet ecosystems absorb far higher quantities of CO2 and far faster than many established ecosystems (Video 1).

Restoring rivers lost to agriculture and weeds will not only provide clean and plentiful freshwater, it will reduce the risk and scale of flooding and deliver more gravel to the coast to replenish coastal margins increasingly at risk of erosion and rising sea levels.

“The conventional wisdom is that you harvest flood water in the winter and store it until it’s needed (for agriculture) in the summer. However, floods are required to carry gravels to the coastal zone and if there’s not enough gravel, the waves get hungry and start eroding the land.” Dr Scott Lanard, NIWA

Video 1: Quick and simple explanation how healthy ecosystems are the most cost effective and efficient way to address climate change

Ecosystem-based adaptation (EbA)

The following is an extract from the United Nations Convention on Biological Diversity:

“Ecosystem-based adaptation (EbA) should be integrated into broader adaptation and development strategies to maintain and increase resilience and reduce vulnerability of ecosystems and people to adverse effects of climate change.

EbA is the use of biodiversity and ecosystem services as part of an overall adaptation strategy to help people adapt to the adverse effects of climate change. EbA aims to maintain and increase the resilience and reduce the vulnerability of people and the ecosystems they rely upon in the face of the adverse effects of climate change. There are various interpretations of EbA, but all share the rationale of working with nature, and most converge on the principle of sustainable management, conservation and restoration of ecosystems, as part of an overall adaptation strategy.

Examples of ecosystem-based disaster risk reduction include restoring coastal vegetated areas such as mangroves to protect shorelines from storm surges; managing invasive alien species linked to land degradation and that threaten food security and water supplies; and managing ecosystems to complement, protect and extend the longevity of investments in hard infrastructure.

In many cases, ecosystem-based disaster risk reduction activities are the same as EbA activities implemented to reduce disaster risk. For example, maintaining and improving the functionality of protection forests is also a key activity within some countries’ climate protection programmes. Because of the important role of forests in mitigating the risks posed by natural hazards, these programme aim to improve the stability and functionality of forest stand structures, foster adapted species mixtures, promote natural regeneration, prevent forest fires and/or control pests and diseases.”

Resources

Fig. 2: Click on this map to be taken to the interactive ‘Christchurch natural ecosystems map’: a key to help you unlock the nature of your place. This map may appear differently when you click on it, as it is being updated and expanded to include the Banks Peninsula and other areas. It includes a native plant list guide for nurseries, designers, and the public to know what naturally belongs within different parts of the greater city, and what growing conditions each species prefers. Note that that areas around rivers are braidplains that were naturally free of all but a few low-lying hardy braided rivers plant species. Restoring these areas means removing introduced trees, pest weeds, and in some areas pasturelands.