The variety of life on Earth has its very own day – International Day for Biological Diversity. Here at DOC, we would happily celebrate biodiversity every day of the year. It’s a great opportunity to highlight the intrinsic value of our natural world and its interconnectedness.
For 80 million years Aotearoa evolved in isolation, resulting in our country becoming a biodiversity hotspot, with many species found nowhere else on earth. All our reptiles, frogs and bats are only found here, while more than 80% of our freshwater fish, invertebrates, trees, ferns and flowering plants are endemic. It’s a lot to get your head around, so let’s bite off a chunk and take a look at a hotspot within a hotspot – the Hauraki Gulf Marine Park/Ko te Pātaka kai o Tīkapa Moana, which celebrates its 20th birthday in 2020 as New Zealand’s first, and only, national park of the sea.
The diversity and interconnectedness of nature plays out beautifully when we consider the importance of the seabirds that visit the Gulf. With more than 70 species, or 20% of the world’s seabird species, utilising the Gulf to feed or breed, the Gulf is considered the seabird capital of world. Their droppings add nutrients to the soil of the islands of the Gulf, which after being mixed by their burrowing activity, provides for the growth of plants, invertebrates and reptiles on the islands.
On the Gulf islands themselves, pest eradication and restoration programmes have created more than 45 island sanctuaries for some of our rarest native species to survive and thrive. Birds, reptiles and insects have been moved to these safe havens to help establish new populations in multiple locations, which provide ‘insurance’ against catastrophic events such as fire, pest invasion or disease on the mainland. This strategy has helped to restore the populations of the near-extinct Mercury Island tusked wētā, tīeke/saddleback, takahē and North Island kōkako.
Also on our islands are fifteen native plant species that you won’t find anywhere else in the Auckland region including woodrose/pua o te reinga, our only fully parasitic flowering plant, and red and white mistletoe whose flowers are “spring-loaded”, exploding open only if opened by a bird with the right-shaped beak.
Nearly a third of the world’s whale and dolphin species visit the Gulf, including orca, sei whales, pygmy blue whales, and common/aihe and bottlenose dolphins. A species that sticks around is the semi-resident population of approximately 135 Bryde’s Whales (pronounced “brooders”), that regularly use the Gulf to feed.
The diversity of fish/ika in the Gulf is incredible, especially when you consider that fish aren’t just fish, but also rays and sharks. The sharp teeth of tāmure/snapper consume a wide variety of foods found on rocky reefs, including heavily armoured shellfish and prickly kina, which helps to reduce the presence of kina barrens (areas where kina have eaten too much), as did the once ubiquitous kōura/crayfish.
Rays such as the spinetail devil ray, and the world’s largest ray, the manta ray, also visit the Gulf. So do a wide variety of sharks/mango including the mako shark, blue shark and tiger shark, many of which use the Gulf as a nursery of sorts. Check out this drone video of a mass grouping of sharks, many of them juvenile hammerheads, taken near Great Barrier Island/Aotea.
Many, if not most, of the species mentioned are threatened or at risk from the threats of fishing, predation, marine pollution, human disturbance, disease, climate change, and loss of prey and habitats. Proposals to improve the health and mauri/lifeforce of the Gulf and the species within it are laid out in 2016 the Sea Change – Tai Timu Tai Pari marine spatial plan, developed over three years by a 14-member collaborative stakeholder working group.
The next phase of island restoration in the Gulf holds the promise of a more sustainable way of living alongside our native species. Waiheke Island could become our first predator-free populated island if the efforts of Te Korowai o Waiheke, the island’s predator-free programme, are successful. Furthermore, Great Barrier Island/Aotea, Kawau and Slipper Islands, all found in the Park, were selected by international researchers as ideal locations for eradication programmes, to help reach the UN’s goal to halt biodiversity loss.
Our natural environment and the biodiversity that lives within it is at the heart of the nation’s identity, shaping our economy, lifestyles and culture. Despite all our technological advances we are completely dependent on healthy and vibrant ecosystems for our health, water, food, medicines, clothes, fuel, shelter and energy. This year’s theme for International Day of Biological Diversity is “Our solutions are in nature”, emphasising hope, solidarity and the importance of working together at all levels to build a future of life in harmony with nature.