World Wide Fund for Nature has found a 73% decline in the average size of monitored wildlife populations in the last 50 years.

Latin America and the Carribbean have seen a 95% decline in wildlife populations, while the decline was 76% in Africa and the Asia-Pacific region has seen a 60% decline.

"The next five years for the trajectory of the health of nature and humans is critical," WWF-New Zealand chief executive Dr Kayla Kingdon-Bebb told 1News.

The leatherback turtle is struggling in the Asia-Pacific region, with a 78% decline in the estimated number of turtle nests at Jamursba Medi Beach in West Papua in the last 27 years.

In New Zealand, Ministry for Primary Industries accidental bycatch data shows 59 leatherback turtles have been injured by fishing practices in the last five years. Three have been killed in the same period.

“Whether it's turtles or whales or seabirds, most of our, for migratory species, the threats that they face are global,” Kingdon-Bebb said.

She said one of a raft of Government policies which can be seen as a “war on nature” is the Fast-Track Approvals Bill.

She’s concerned about some of the development projects on the Fast-Track list that have previously been rejected by the Environmental Protection Authority.

One of these is the Hananui Aquaculture Project to operate salmon farming off the coast of Stewart Island/Rakiura.

The island is one of the Southland locations where the northern population of the endangered hoiho penguin breeds.

“The impact of a salmon farm where you have sort of waste from feed etcetera, over their foraging grounds, is likely to be significant, possibly the nail in the coffin for that species which is already really struggling to survive,” Kingdon-Bebb said.

Regional Development Minister Shane Jones said environmental considerations will be required.

“The mining ones, mitigation will be important, in relation to aquaculture I'm sure there'll be some scientific remedies but it's really important that economic rationalism and science guide the decision making rather than dramatisation by the green groups,” Jones said.

Zealandia Te Māra a Tāne chief executive Dr Danielle Shanahan said with devastating biodiversity outcomes globally, the ecosanctuary is an example to New Zealand policymakers and those around the world on how to reverse species decline.

"Zealandia shows that if we actually invest in nature, if we invest in the solutions, if we're brave and we're innovative, we can reverse the decline.

"Those examples can be deployed everywhere, they're solutions that are open source knowledge for us to tap into and actually create the change that we need for the future."

Zealandia’s story is a "beacon of hope" that biodiversity loss can be improved, she said.

The not-for-profit organisation transferred kākā to the ecosanctuary in 2002.

The native parrot hadn’t been seen in Wellington since the early 20th century.

“What's happened is not only is nature thriving within the sanctuary fence but in fact we've seen a reversal of the loss of our bird biodiversity from the skies of Wellington,” she said.

“We have kākā, once extinct from this region, now showing up just outside the Beehive so this just demonstrates that again if we are brave, if we are bold, if we are innovative, we can reverse that loss.”

Shanahan said everyone has a role to play in conservation efforts.

“Zealandia of course got things humming, it gave a safe place for these birds to breed, to find food but actually those two (kākā and tui) are doing well because other people are taking up pest control in their own backyards, because of Predator Free Wellington, because of Capital Kiwi, all these other projects.

“Everybody's effort makes a difference and I think that's where we need to look for our hope for the future.”