Drone used to replant cliffs

A drone is being used as an innovative way to replant cliff faces south of Waipukurau.

The cliffs at Te Angiangi Marine Reserve have been bare since a bad storm in April 2011 with 550mm rainfall and a 4.6M earthquake caused them to collapse.

The Department of Conservation is now replanting them with flax seeds in biodegradable coffee cups using a drone.

DoC Hawke's Bay biodiversity coastal marine compliance ranger Rod Hansen said they bought a drone last year to help find illegal whitebaiters along riverbeds and decided to use it for this purpose too.

The project started a few months ago but has been slow because they had to spread plantings out due to various weather events increasing the chance of seeds washing away of falling into cracks.

"We put a load on every now and then," he said.

Two DoC employees have drone licences in Hawke's Bay so have been undertaking the project which has so far been about 150 loads.

Tens of thousands of seeds have been dropped on to the cliff faces in the hopes that some will take, he said.

They have been dropped in biodegradable coffee cups covered in wet soil attached to the drones with cotton nooses so there is no waste.

Flax seeds have been used because of their ability to take to harsh environments and their sturdiness, Mr Hansen said.

The cliff faces are inaccessible by foot so the only other way to plant would be by helicopter which would not be as accurate and would be too expensive.

Mr Hansen said he believes Hawke's Bay is the only DoC branch in the country to have a drone but hoped they would be considered elsewhere because of their success and versatility.

Using them to find illegal whitebaiters, invasive seeds or to replant cliff faces would save a lot of time and money with much higher accuracy rates than using a helicopter or by foot, he said.

"I think it's going to be hugely successful."

Replanting the cliff faces will be good for the whole ecosystem in the area but also for the water quality of the marine reserve, Mr Hansen said.

At the moment sediment from the bare cliff faces goes straight into the sea causing problems for marine life.

But having plants there will stop this from happening.

The drone is powered by rechargeable batteries which last 28 minutes each.

The pilots stand on the beach at the bottom of the cliffs and are able to do quite a few loads in that time, Mr Hansen said.

The beach at the bottom of the cliff was replanted with the help of the Aramoana Environmental and Education Charitable Trust, DoC and the local iwi.

All of the flax seeds were picked by volunteers.