Missing In Northland Forests For 30 Years

Checking the contents of possum stomachs and painstaking searches of Northland forests gave Conservation Officer Scott Candy the trained eye needed to make a historic plant find.

It had been 30 years since evidence of the rare root parasite Dactylanthus taylorii was last found in pollen samples taken from short-tailed bat droppings in Omahuta Forest but, now the efforts of Scott Candy have found the elusive plant in the region once again.

Also known as pua o te Reinga, Dactylanthus is only found in New Zealand, with its stronghold being the Central North Island. Until it this discovery in Puketi, the most northern surviving population of the plant was on Little Barrier Island.

Familiar with the plant because of his involvement in a Dactylanthus survey of Omahuta Forest last year (which did not turn up any sign of the plant), Scott took a closer look at unusual diggings around a large clump of dirt – which turned out to be the plant.

“Last year, I had spent one month looking at the stomach contents of possums for the telltale red staining which only happens when a possum has eaten Dactylanthus.” explained Conservation Officer Scott Candy “I knew when I saw the diggings – it could only be Dactylanthus”.

Collectors of the plant considered it common in Omahuta Forest and near Mangonui up until the 1970’s. However, with over-collecting and possum damage it has been in decline nationally over the past century and there are now thought to be only a few thousand plants remaining. In fact, botanists have confirmed no sightings of the plant in Northland since the beginning of the 1900’s.

“We had reports of it from collectors, and evidence from bat droppings but this is the first time we will be able to go and look at an actual specimen and consider ways to protect it.” explained Conservancy Advisory Scientist, Avi Holzapfel. “We know that other known populations are genetically different and we are anxious to find out if the Puketi population differs as well.”

Dactylanthus holds a special place in New Zealand’s flora, being our only fully parasitic plant. It obtains all its food and water from the roots of the host plant to which it is attached. Dactylanthus has no green leaves or roots of its own. It occurs largely under the surface of the soil, until its brown flower spikes emerge above ground around this time of year. Dactylanthus is a very cryptic plant on the forest floor – making it more remarkable that Scott spotted it.

Dactylanthus has a close association with the threatened native short-tailed bat, which is also found in Puketi Forest. The bats feed on the copious amounts of nectar produced by the flowering plant and in the course of feeding, pollinate the flowers of Dactylanthus.

Unfortunately the strongly scented nectar also attracts predators to the plant, with possums causing the greatest damage, breaking flowers and even uprooting entire Dactylanthus rhizomes. This is the digging Scott first noticed that led to the finding. Damage to the flowers prevents the production of seed, and therefore threatens future survival of the population.

Additional survey of the area this week, found several other specimens of Dactylanthus. Scott and the Department’s threatened species team, will construct small cages over the plants to prevent further possum damage. Netting which still allows short-tailed bats to pass through will be used. Surveys will continue while the plant flowers from now through until May.

Dactylanthus is generally found growing on species of trees which re-colonise a site following disturbance (slips, tree-falls, fire). Host plants include mahoe, pate, Pittosporum species, hangehange and mapou.

The Department of Conservation is very interested in hearing from members of the public who may know of sightings of Dactylanthus, especially in Northland, Auckland, Wellington, Nelson-Marlborough and all areas where the plant was once known. Individuals are encouraged to contact their local Department of Conservation office.

ENDS

For more information please contact Karen Riddell or Shelley Clendenon on (09) 407 8474

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