Climate Change Vulnerability Assessment (CCVA)

Assessing the vulnerability of taonga freshwater species to climate change

To prepare for changes in climate, our freshwater and oceans decision-makers need information on species vulnerability to climate change.

Te Wai Māori Trust recognises that the impacts of climate change on taonga freshwater species needs to be factored in to effectively manage and conserve taonga species in Aotearoa-New Zealand. In 2019 they, with co-funding from the CK2020 programme, commissioned NIWA to complete a Climate Change Vulnerability Assessment (CCVA) on the vulnerability of 10 freshwater taonga species (eight fish and two invertebrates).

What is a Climate Change Vulnerability Assessment?

Climate Change Vulnerability Assessments are a structured, transparent and reproducible methodology that can be used to assess species' vulnerability to climate change. The CCVA methodology is used internationally and allows for a diverse set of freshwater taonga species to be assessed using existing information and expert opinion in a relatively short period of time. This study is the first application of CCVAs to freshwater taonga species in Aotearoa.

CCVAs identify which species may be most vulnerable to climate change in the future based on:

their exposure to predicted changes in the environment (e.g., warming oceans or more frequent droughts)
their sensitivity or ability to cope with changes in their environment based on their unique characteristics (e.g., food, habitats, reproduction).

Together, exposure and sensitivity form a species’ climate change vulnerability score.

CCVAs rank species' vulnerability to climate change and do not measure what the effects of climate change will be (i.e., changes in species distributions, increased mortalities due to extreme temperatures). This is one of the main limitations of CCVAs.