Aftermath: Cyclone adds to spinifex problem

e resilience of dunes and the sustainability of the sand-binding kōwhangatara/ spinifex is being keenly felt by Coastcare groups in the eastern Coromandel Peninsula.

“Summer o ers a small window of opportunity to collect the seeds of the native dune grass from which the following year’s plantings are grown,” says Mercury Bay Environmental Trust project manager Kim Lawry. But with many of the seedheads swept away in Cyclone Hale’s fury, Coastcare groups from Whangapoua, Matarangi, Kūaotunu, Ōpito Bay, Wharekaho, Bu alo Beach, Onemana and Whangamatā

“weren’t able to get as many as we’d like” this year.

Collecting seedheads has become an important part in the process of dune restoration, says Kim.

Interference

Kōwhangatara is the main dune forming indigenous plant in New Zealand.

“Historically, spinifex didn’t reproduce by seed. ey didn’t need our help at all.

“Instead, they survived the dynamic seafront through a cycle involving retreating inland and advancing back toward the water.

“After a storm, spinifex would naturally walk backward and sends runners inland to re-establish further up dune ... that was before coastal squeeze interfered with this process and now we can’t just leave them to it. On many of our beaches, spinifex has limited space to retreat inland. We don’t have enough room between the shoreline and the houses and roads.”

Collected seedheads are instead sent every year to Coastlands Plant Nursery in Whakatane for germination and growth.

“ e window of opportunity to pick is small – you have to pick plants at the time the plants are releasing,” says Kim.

“We go in and tickle under the heads and when they pop o we take them. If you pick before the seeds are mature, then the germination rate is lower.”

He says another issue threatening kōwhangatara supply is the di culty of growing the plants and that there is no nancial return for all the hard mahi (work).

“It gives commercial nurseries no incentive to assist in spinifex supply.

“Growing the plants is a labour intensive process. After manually extracting seeds from the heads, each one has to be squeezed to check it’s viable.

Working together

“In the past, we could keep up with demands, but the more we’ve learnt about how important spinifex is, the more our demand has increased.

“ is problem of not enough spinifex … I was at a conference and spoke about this. e people that came up to talk to me afterward all had the same problem.”

It doesn’t help that the average number of viable seeds per head has gone down considerably over the past years.

Kim believes this could be due to climate change.

“ e prevailing winds we’re getting now may not allow for pollination to happen as it should.”

Innovation in growing spinifex is required to ensure its sustainability.

“ e idea for a nursery in Whitianga has been raised though it would require a purpose-built nursery that supports the narrow temperature ranges required for spring germination.

“We need to talk to universities to nd a better way to grow spinifex that is more e cient and less labour intensive.”