International Day for Biodiversity 2026

From Tiritiri Matangi to Pukekawa / Auckland Domain, four decades of conservation are reconnecting nature across the city.

Blog by Matt Rayner, Senior Researcher Auckland Museum

On any given morning at Pukekawa, the historic maunga on which Auckland Museum sits, the ringing call of a tūī carries through the trees. Kererū crash awkwardly between towering pūriri, and riroriro deliver their delicate songs from high in the canopy.

For local residents living near the domain, these birds are simply part of the citys soundtrack. But their presence tells inspiring conservation story.

The theme of this years International Day for Biological Diversity is “Acting locally for global impact.” It is a reminder that biodiversity recovery begins with local action—planting trees, removing predators, restoring habitats, and protecting the natural spaces around us.

Few places demonstrate this better than Auckland.

^{View toward the Robert Burns Statue and Auckland War Memorial Museum from Domain Drive. Photographed by Una Garlick, 1920s-1930s. Collection of Auckland War Memorial Museum PH-1989-14-285.}

A Conservation Revolution Begins

In 1984, an ambitious restoration project began on Tiritiri Matangi Island in the Hauraki Gulf. Thousands of volunteers, “the spade brigade” planted more than 280,000 native trees, transforming a grazed island farm into a internationally recognized sanctuary.

That effort helped launch a broader movement across the region.
Over the following decades, invasive mammals were eradicated from islands throughout the Hauraki Gulf, including the remote Mokohinau Islands and Te Hauturu-o-Toi / Little Barrier Island, where Pacific rats were removed in 2004. Mainland sanctuaries such as Tāwharanui and Shakespear Regional Parks showed that biodiversity could also recover on the mainland when predators were excluded. Large-scale pest control programmes in the Waitākere and Hunua Ranges expanded these gains even further.

Together, these projects created an interconnected network of safe habitats surrounding New Zealand’s largest city.

The Spade Brigade planting trees, by G Thew, 1989. Courtesy of the Supporters of Tiritiri Matangi I

When Nature Spills Back into the City

Birds do not recognize the boundaries between offshore islands, rural forests and urban parks.

Highly mobile species such as tūī move across the landscape in search of nectar, fruit and nesting sites. As populations increased in protected areas, birds have increased in abundance in forests, parks and gardens throughout Auckland. This process is known as ecological spillover—the idea that conservation in one place can generate benefits far beyond the original restoration site. The results are now visible in the heart of the city.

^{Pictured: tūī (Prosthemadera novaeseelandiae)}

Map outlining the area where trees will be planted in Pukekaka Auckland Domain

Pukekawa: An underrated urban sanctuary

Pukekawa / Auckland Domain is Auckland’s oldest park and contains more than 70 hectares of mature forest, making it the largest continuous patch of forest in central Auckland.

Running through part of this ngahere is the stream Te Ako o te Tūī, which translates as “The Teaching of the Tūī.” It is a fitting name for a place where the calls of tūī now ring through the forest and where nature continues to teach us about the resilience and interconnectedness of urban ecosystems.

^{Plan of position and particulars of native trees [in the] Auckland Domain. James Stewart, 1905. Collection of Auckland War Memorial Museum, G9081.K2.}

In a recent study, my colleague Dr Josie Galbraith and I compared bird surveys conducted in the Domain in 1987–88 with identical surveys repeated in 2019–20. We found that both the abundance and diversity of birds had increased substantially over the intervening three decades.

The most dramatic change was the rise of tūī, which went from being an occasional visitor in the 1980s to the most abundant native bird recorded in our surveys. Forest loving kererū and riroriro also increased markedly.

These changes reflect a combination of factors: planting of trees and the maturation of the domains forest, local pest control by council and community groups and the wider regional conservation efforts that have rebuilt bird populations across Tamaki.

^{pictured: tūī Prosthemadera novaeseelandiae}

Biodiversity Is More Than Birds

Birds are among the most visible signs of ecological recovery, but they are only one part of a much larger and more intricate web of life.

The forests of Pukekawa support native and exotic trees, fungi, insects, spiders, and countless microscopic organisms in the soil. Around Te Ako o te Tūī, the ngahere also harbours remnant native lichens, ferns, mosses, and liverworts—small but remarkable survivors that add to the botanical and mycological diversity of this urban forest.

Together, these species form an interconnected ecosystem in which each plays a role.

Tūī provide an excellent example of this connection. Their increase in abundance across the Tāmaki isthmus is more than just a success story for one iconic bird. As they move between flowering plants such as kōwhai, harakeke, and pūriri, tūī act as important pollinators, helping native trees and shrubs to reproduce. Those plants then produce nectar, fruit, and foliage that support insects and other invertebrates, which in turn become food for other animals.

In this way, the recovery of tūī helps strengthen ecological processes that benefit biodiversity throughout the food web.

Pukekawa is therefore much more than just a city park. It is a living ecosystem where birds, plants, fungi, lichens, and invertebrates interact every day, demonstrating how conservation restores not only species, but also the relationships that connect them.

Everything is Connected

The tūī singing outside my office at Auckland Musuem today may owe its presence to trees planted by volunteers in the domain and on Tiritiri Matangi over the past 50 or more years, to predator eradication on offshore islands, to pest control in the Waitākere and Hunua Ranges, and to the protection of urban forests like Pukekawa.

Everything is connected. And when we restore habitats locally, whether on a nearby island island, in a regional park, or in the heart of the city - the benefits ripple across the landscape.

Pukekawa stands as a living reminder that small actions, taken consistently over time, can help restore biodiversity and reconnect people with nature. In doing so, local action can indeed have global impact.