Native ecosystems are our climate superheroes
Image: Hercules Creek – Steve Attwood
Native ecosystems are our 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 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.
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. Yet this is still the situation. These ongoing losses of biodiversity and increasing carbons emissions are occuring at a time when they must be rapidly reduced. It’s also undermining our greatest allies in our ability to adapt to and mitigate the impacts of climate change.
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
Protecting what’s left of existing ecosystems is the most cost-effective in terms of dollars, labour (voluntary and paid), biodiversity, and cultural outcomes. This immediately prevents large amounts of CO2 from entering the atmosphere, acts as a shock absorbers against the impacts of climate change, and provides ongoing life-supporting ecosystem services.
Enable regeneration of damaged areas. While this is costlier and takes longer that protecting what’s left, because we have lost so much, regeneration is an essential stratgey in helping to mitigate the projected impacts if climate change across Aorearoa by:
- Reducing the impacts of flooding (see rivers).
- Reducing the short-term and delaying the long-term impacts of rising sea levels and storm surges (see coastal dunes and estuaries).
- Reducing the impact of heatwaves (see land use)
- Reducing the impact of wildfires, which predominantly take hold in non-native forests (see the video Hinewai Reserve as a case study in wildfire on the Banks Peninsula, and ‘the problem with pines‘).
- Restoring ecosystem services including pollination, nutrient recycling, filtering out contaminants including heavy metals and nitrates (see ecosystem services).
- Improving water quality (see rivers and wetlands).
- Improve the quantity and qualility of mahinga kai that’s also safe to eat and use (see rivers, wetlands, and estuaries).
- Draw CO2 from the atmosphere and sequester it back in the ground (see the carbon cycle).
The best approach is to restore or replace lost ecosystems on the borders of existing native ecosystems, as intact ecosystems already host native birds and invertebrates. These creatures do the heavy lifting by spreading seeds, pollinate young plants, and helping to restore native soils, which provide the essential yet generally overlooked foundations for natural ecosystems.
Use well-understood and proven strategies to protect both existing and regenerating areas. This usually involves a combination of some or all of the following, depending on the type of ecosystem and its location:
- Fencing to keep out livestock and pest herbivores including (depending on the location) rabbits, deer, pigs, tahr, chamois, and wallabies. The costs of these pest species to Aotearoa’s nature and climate is staggering.
- Trapping to kill predators, which kill native birds and invertebrates needed to provide and restore essential ecosystem services.
- Weeding this includes removing wilding pines and other introduced plants strangling our wetlands, forests, and rivers.
- Retaining gorse in strategic location. This pest plant is much hated by agriculturalists, but it’s proven to be a surprisingly good nursery plant for regenerating native forests. This has been amply demonstrated at Hinewai Reserve, Banks Peninsular.
Reinstating ‘wet’ ecosystems including dune systems, saltwater marshes, seagrasses, kelp forests, rivers and wetlands is labour intensive but it takes less time for them to mature than forests. Newly restored wet ecosystems also absorb far higher quantities of CO2 and far faster than many established ecosystems (Video 1). While 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 also 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
Incentivise the protection and restoration of native ecosystems as an absolute priority under the Emissions Trading Scheme.
Disincentivise through economic mechanisms (primarily the ETS) the conversion of land currently used for other purposes (such as agriculture and plantation forestry ) into any uses other than restoring native ecosystems.
Make policies more robust so that non-compliance with land clearing rules can readily be prosecuted.
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.”
Every page in this ‘Native Ecosystems’ section (see the menu at the top of this page) and the pages in ‘Our places‘ includes resources to enable protection and restoration of different types of ecosystems. It includes the contact details of people and groups undertaking and supporting these projects.
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: the grey area around the Waimakarari River is a braidplain. It should not have any plants. While a very few braided rivers plant species once lived along parts of the river, braidplain ecosystems should be entirely free of all introduced plants including pasturelands.
The cost of planting new native forests vs protecting existing native forests
Restoration planting costs about 100 times as much per hectare (sometimes more) as it does to protect pre-existing remnant vegetation, and is less likely to result in the same ecologically desired outcome as protecting existing forests. On-the-ground costs associated with 15 recent examples of remnant vegetation protection in North Canterbury hill-country QEII covenants and strategic restoration plantings came in at about $655/ha:
- $595/ha for fencing
- $55/ha for initial pest & weed control
- $5/ha for strategic restoration planting
- Likely ongoing maintenance costs were not included
The likely cost of establishing planted stock with a minimum of 1 weed control operation per year for the two years after planting came in at $63,900/ha. If the site required 5 weed control visits per year in the two years after planting, the cost would rise to about $103,900/ha. When closer plant spacing is required (as is often the case for wetlands) then the cost will rise (most likely nearer $150,000/ha).
This does not mean we should not replant natives. Rather, it advocates for protecting every hectare we have, encouraging natural regeneration bordering native forests using strategies outlined on this page. For example, the model used by EKOS in the Tasman District.
References and further reading
- 2021: COP26 – Adaptation
- 2021: IPBES-IPCC- Biodiversity and Climate Change Workshop
- New Zealand Climate Change Commission
- It’s time, Canterbury – our climate change conversation
- 2021: Ināia tonu nei:a low emissions future for Aotearoa – Advice to the New Zealand Government on its first three emissions budgets and direction for its emissions reduction plan 2022 – 2025, Climate Change Commission
- 2021: The Economics of Biodiversity: The Dasgupta Review. London: HM Treasury
- 2021: New Zealand Statistics: Indigenous land cover
- Convention on Biological Diversity: Ecosystem Based Adaptation
- 2020: Strassburg et al; Global priority areas for ecosystem restoration Nature article
- 2020: Kobayashi and Vargas in World Wildlife Fund Living Planet Report, 2020
- 2019: Lewis & Wheeler; Restoring natural forests is the best way to remove atmospheric carbon, Nature article (open access)
- 2019: Lewis & Wheeler open access article on the above; The scandal of calling plantations ‘forest restoration’ is putting climate targets at risk, The Conversation
- 2018: Warren et al; The implications of the United Nations Paris Agreement on climate change for globally significant biodiversity areas, Climate Change 147 pp395-409
- 2014: Christie (DOC); Adapting to a changing climate: A proposed framework for the conservation of terrestrial native biodiversity in New Zealand
- 2008 Ausselie et al; Wetland ecosystems of national importance for biodiversity: Criteria, methods
and candidate list of nationally important wetlands, Landcare Research Manaaki Whenua