365 Days of Climate Awareness 203 – Impacts on New Zealand Native Species

A combination of changing ambient conditions and one-time events can have huge effects on an ecosystem, disrupting it possibly past recovery. This has happened in New Zealand, particularly in the marine environment. With such a wide range of habitats, and occupying a relatively small area, New Zealand’s ecosystems are particularly vulnerable.

Hoiho (yellow-eyed penguins).

Air and sea surface temperatures have been rising for decades. In 2017-18, marine and terrestrial heat waves combined with windless weather to produce deadly conditions for a number of near-coastal marine species. Stands of bull kelp (rimarupa) were lost completely at a number of reefs and suffered a 75% decline elsewhere. The kelp’s place was taken by the sea grass Undaria, and local mussel populations collapsed. In Lake Wānaka on the South Island, warmer water temperatures have led to a new species of phytoplankton taking over for the native variety. It is unclear right now how the species shift will affect the rest of the food web—a high likelihood since phytoplankton are primary producers.

Kiwi bird.

Larger land animals are also affected. High temperatures can lead to “mast” events, where plants overproduce and lead to population booms in mice, rats and ermine, which pose an increased threat to the already-dwindling local kiwi. Increased sea level and frequency of storms has made it more difficult for the yellow-eyed penguin (hoiho) to find food. And the eggs of the tuatara lizard become thinner in hotter conditions, leading to increased mortality of unhatched chicks.

Tuatara.

The warming seasons have also affected agriculture. The decline in annual freezing days has decreased the productivity of kiwi fruit trees. Increased summer heat damagesthe quality of grapes and negatively impacts the health of cattle, among other livestock.

Ermine (not the villains here! And neither are the mice or rats! They're all just surviving. But ermines are indisputably cuter.)

Tomorrow: changes in the East Australia Current.

Be brave, and be well.