An "at risk" species of mistletoe is staging a remarkable comeback in parts of a Hawke's Bay forest following a successful possum eradication programme.
More than 200 specimens of yellow mistletoe (Alepis flavida), known as pirita or piriraki in te reo Māori, have been found in the past year by the Forest Lifeforce Restoration Trust on its property in the Maungataniwha Native Forest, adjacent to Te Urewera.
The parasitic species has leap-frogged from being unrecorded in the forest to having 21 plants seen within one host tree alone. On a single day in February this year trust volunteers and staff found 109 new plants on 49 host trees, a record daily tally for the area.
Trust manager Pete Shaw said he was "staggered" by the finds.
"It's the most remarkable change in the forest we've seen for years," Shaw said. "It's notable that the recovery is not obvious across the entire forest, though, so it's possible that we've stumbled across one or two hot-spots where this species wasn't entirely wiped out by the possums before we started our work here in 2006."
The trust's possum eradication work in the Maungataniwha Native Forest has been so successful that in the past year any possum seen at night was an "exceptional event". Determined trapping and targeting of the few remaining animals by staffer Barry Crene has helped keep the number of these pests low.
"Barry's got it to the point now that every possum killed at this stage could mean keeping the lid on the possum numbers in this forest for future years," Shaw said. "It's vital for the health of our forest that we are able to do this."
The nearby Department of Conservation-administered Boundary Stream Mainland Island also experienced a rapid recovery of yellow mistletoe following possum-control there.
The pattern of the plant's recovery at Maungataniwha should continue in future years if possum control continues, the trust says.
"We're hoping that yellow mistletoe may be reaching a critical mass that could result in lots of available seed being flown by birds, and a much faster recovery into the future."
The Forest Lifeforce Restoration Trust was established in 2006 to provide direction and funding for the restoration of threatened species of fauna and flora, and to restore the ngahere mauri (forest lifeforce) in native forests within the Central North Island.
It runs eight main regeneration and restoration projects, involving native New Zealand flora and fauna, on three properties in the central North Island. It also owns a property in the South Island's Fiordland National Park.