Trithuria-inconspicua. Photo / Dennis Gordon, Niwa
A tiny and hugely rare Northland lake plant has been voted New Zealand’s Favourite Plant.
Trithuria inconspicua was given the top honour after an online vote, run by the New Zealand Plant Conservation Network (NZPCN), to find New Zealanders’ best loved native plant,
The little plant grows only in Te Taitokerau’s dune lakes and is not only one of this country’s rarest plants but is not found anywhere else in the world, Northland Regional Council (NRC) said in a press release.
Tiny in stature, Trithuria packed a mighty punch in age - the latest scientific research had revealed this little plant to be in the oldest flowering plant lineage. Trithuria was in a plant family that had been around for over a hundred million years, so it was a “living fossil”, NRC said.
The plant certainly lived up to its name of “inconspicua”. At only 55mm tall, it grew partially buried in the sands of the lake floor, so was more likely to be felt beneath people’s feet than actually seen. It had fans of fine, hair-like leaves in which it hid tiny flowers that looked like miniature waterlilies.
NRC said it worked in partnership with mana whenua, landowners and the Department of Conservation (DoC) to protect dune lakes and was delighted to celebrate Trithuria’s success.
“It’s so exciting that a Northland aquatic plant has won, and that people know and love this remarkable little plant,” the council’s biodiversity manager Lisa Forester said.
Kaumātua Ric Pārore, speaking on behalf of Te Kuihi hapū, one of the mana whenua of Kai Iwi Lakes, said they were thrilled to see Trithuria recognised, but also sad the plant had become so rare.
“It’s important that everyone who visits or uses our lakes is careful to look after them so this plant can thrive.”
Unfortunately, the future for Trithuria was uncertain.
It was listed as Threatened-Nationally Critical, the highest threat category. Plant populations were previously found in 13 dune lakes north of Poutō, but since 1998 these had declined to viable populations in only five lakes.
Trithuria needed clean sand and water to survive and was effectively a “canary in the coal mine” as far as water quality was concerned. It was threatened by deteriorating water quality due to nutrient enrichment, pest weed and pest fish impacts and recreational pressures.
Three of the lakes where Trithuria grew were public lakes where people like to swim or boat, which puts the plant at extra risk from being trampled or from accidental pest introductions.
NRC and its partner stakeholders were currently running eradication programmes for hornwort and oxygen weeds in several high value dune lakes.
Councillor Jack Craw, the council’s Biosecurity and Biodiversity Working Party chairman said Te Taitokerau’s dune lakes were one of New Zealand’s outstanding ecosystems and were globally rare.
“Trithuria is a wonderful example of why these lakes are so special and its recognition as plant of the year is a reminder to us all of the importance of caring for our dune lakes.”
Dune lakes and their biodiversity faced many threats, including the risk of introduced pests like the invasive gold clam, which was now present in the Waikato River area, Craw said.
“If this got into our lakes it would be disastrous and would almost certainly lead to the extinction of Trithuria in those lakes.”
Northlanders could help prevent the spread of aquatic pests by following “Check Clean Dry” procedures when visiting the lakes, Craw said.
“If you do see Trithuria, the NRC urges you not to pick it, dig it up or trample it...just leave it undisturbed. It is very difficult to grow and will not survive in an aquarium or home pond.”
For more information on this special plant visit: www.nrc.govt.nz/trithuria