CURRENT THREATS

Kauri Dieback Management Programme

10 February 2014

Several media outlets have been running a story stating that the Kauri Dieback Management Programme has been extended for the next 5 – 10 years. To clarify, June 2014 will see the end of the first phase of the Programme and associated funding. While we are confident that the Programme will continue is some form, what that will look like and funding for the next phase is still to be determined.

Kauri Dieback

Kauri trees continue to die from infection by Phytophthora taxon Agathis (PTA). 65% of infected trees are along the walking tracks in the ranges, indicating that the disease is the spread by mud on walkers’ boots.

There is currently little understanding of the disease, its spread and management. There is no cure - every tree that gets infected dies. The science and management programs are currently only funded until the middle of this year, and ongoing funding from Ministry of Primary Industries has not been confirmed.

Eighteen months ago Council closed 27 kms of walking tracks through areas of the regional park where there is no evidence of the disease and these tracks remain closed to the public in the hope that this might halt the spread of the disease. La Trobe track at Karekare is one of the tracks closed. However, compliance with the track closures is low.

This is possibly because public understanding of the potential of this pathogen to spread and destroy even more kauri is poor, and future management programs must include better education about this disease.

For more information call John Edgar (09) 818 7447

Kauri Dieback Disease-Two Dead KauriKauri Dieback disease-dead kauri at Arataki Visitors Centre. Photo courtesy Ted Scott

Photograph above showing a Kauri tree at Arataki Visitors Centre. Ted Scott took the first photograph in September 2013 and the second photograph in February 2014.

As reported by Dr Nick Waipara at Auckland Council this tree suffered from an exotic Phytophthora root pathogen. The organism isolated was Phytophthora multivora, a soil associated root pathogen of kauri (and other plant species, so it is a generalist pathogen and not a Kauri specialist like PTA).

It is not a new problem to NZ or kauri and we know it has been associated with sudden decline/collapse of trees in West Auckland previously. This disease works synergistically with other Phytophthora spp. (e.g. PTA), environmental stress (e.g. drought/dry weather, nutrition stress, soil compaction etc.) to cause ill-health/ and in some cases like this, can cause death. Dr Waipara suspects (from soil surveillance to date) that this pathogen is already very widespread, as it is also soilborne, the same management procedures for PTA e.g. hygiene measures of cleaning gear and minimising soil movement will reduce/slow further spread. Auckland Council will be investigating control measures to assist landowners treat P. multivora infection on sick trees/plants.

Kauri Dieback Study looks at the effects of kauri dieback on forest ecosystem

13 January 2014

Donal van der Westhuizen from the University of Auckland is studying the impacts of kauri dieback on kauri forest ecosystem processes.

Donal's work has been based at a diseased site at Huia in the Waitakere Ranges. This study has measured changes in litterfall, soil respiration and understory vegetation.

Conclusions from his work so far include:

  • Changes in litterfall quantity and composition may result in long term changes in decomposition rates and soil chemistry
  • Decreased reproductive capacity of infected kauri may affect the succession of kauri
  • No difference in soil CO2 efflux suggests that roots still respire and/or accelerated microbial activity in the medium/highly infected sites
  • Differences in temperature sensitivity indicates a change in root versus microbial respiration
  • Changes in surrounding regenerative vegetation may result in long term changes in forest composition.

kauridieback.co.nz

Pest Plants

Pest Plants are a concern to Forest and Bird as they are a major threat to the Waitakare Ranges Heritage Area which was established to protect and maintain native flora and fauna. Pest plants also threaten our local bush and gardens. Some of them are food for NZ’s native birds but our native trees need our native birds to prosper and pest plants are diverting them! There are several excellent national web sites to help you deal with your pest plants but here we also add a local perspective.

As many of these pests do not compost but just keep growing try weedfree.org.nz for the location of the weed bin nearest to you. In March they are sited throughout specific areas but there are some permanent ones. Containers for drowning ginger, Weed Containment bags, or War on Weeds bags are available from the Weedfree Trust at various prices, phone (09) 826 4276

Please do not tip any pest plants anywhere!

When the pests are dead consider replanting with natives, as weeds love a vacuum and will soon take advantage of fallow ground.

Myrtle Rust

In May 2014 Auckland Council released a media statement calling for help with recognising and notifying a new potential threat Myrtle Rust.

"Please help us get prepared!"

They report that a strong, blustery westerly wind could blow a new significant pest over the Tasman Sea and infect our native Myrtaceae species.

Myrtle rust (Puccinia psidii) is a fungus that attacks the new growth leaves, shoots and flowers of native Myrtaceae species and also the introduced eucalyptus, guava and feijoa.

This fungus is NOT in New Zealand yet, but has spread and established on Australia's east coast.

If you see myrtle rust in New Zealand, please contact the Ministry for Primary Industries immediately on the Pests & Diseases Hotline 0800 80 99 66 and report the location. If possible take a photo. Do not attempt to collect samples as this could increase the spread of this disease. MPI will dispatch investigators to collect samples safely.

See Mrytle Rust Fact sheet here.