TRILEPIDEA Newsletter of the New Zealand Plant Conservation Network NO. 175 Th e latest review of the threat status New Zealand’s indigenous fl ora June 2018 Peter J. de Lange, Environmental & Animal Sciences, Unitec Institute of Technology, Deadline for next issue: Mt Albert, Auckland, New Zealand ([email protected]) Monday 16 July 2018 Over a fi ve yearly cycle, the Department of SUBMIT AN ARTICLE Conservation hosts a panel of experts representing TO THE NEWSLETTER a range of skills and interest groups to undertake Contributions are welcome threat listings of New Zealand’s biota. Two weeks to the newsletter at any ago the eighth conservation assessment of the New time. The closing date for Zealand Vascular Flora was published as part of NEW ZEALAND THREAT CLASSIFICATION SERIES 22 articles for each issue is approximately the 15th of the New Zealand Th reat Classifi cation Series (Vol. each month. 22). Th e new listing replaces the previous listing Conservation status of Articles may be edited and prepared in 2012 and published in 2013. New Zealand indigenous used in the newsletter and/ vascular plants, 2017 Peter J. de Lange, Jeremy R. Rolfe, John W. Barkla, Shannel P. Courtney, Paul D. Champion, Th e situation for the New Zealand indigenous Leon R. Perrie, Sarah M. Beadel, Kerry A. Ford, Ilse Breitwieser, Ines Schönberger, or on the website news page. Rowan Hindmarsh-Walls, Peter B. Heenan and Kate Ladley The Network will publish fl ora is not good; 2502 taxa at the rank of almost any article about species, and 283 taxonomically indeterminate plants and plant conservation and/or informally recognized ‘tag-named’ with a particular focus on the plant life of New Zealand and taxa were assessed. Th ese fi gures represent the Oceania. most accurate statement of the New Zealand Please send news items Indigenous Vascular Flora currently available. Seven or event information to taxa are listed as ‘Extinct’ (one less than the 2012 listing), and 403 taxa are listed as [email protected] ‘Th reatened’ (114 more than in the previous listing). Sixty-one taxa have experienced Postal address: c/- 160 Wilton Road severe documented declines since the last listing, 59 taxa now have worse conservation Wilton assessments, and another 77 have a worsening conservation status. Th ese declines can Wellington 6012 be directly mapped to deteriorating water quality, the impact of dairy farming in the NEW ZEALAND inter-montane basins of the eastern South Island, ongoing loss of habitat, and direct pressure from browsing animals and from diseases. In some cases, the cause of decline remains unclear. For example, the poroporo (Solanum aviculare var. aviculare) once abundant 30–40 years ago in the North Island PLANT OF THE MONTH, p. 2 is now in serious decline, such that it is either absent from or in sharp decline over large parts of its former range. Oddly, whilst it is in decline, its close relative Solanum laciniatum is not; in some places it is actively spreading into habitat S. aviculare var. aviculare once occupied. Even stranger, is that the off shore island race of S. aviculare var. latifolium is also spreading in places where it has been planted on the mainland. Research as to why this happening is urgently needed. In the case of kauri (Agathis australis), the cause of the decline is now well known and, for the fi rst time, this iconic conifer has been listed as ‘Nationally Vulnerable’, refl ecting the impact of the killer disease, Phytophthora agathidicida, a listing made possible because a predicted decline rate and a national population estimate for kauri now exists. Less certain has been the call to list all New Zealand’s indigenous myrtles Pachycladon crenatum. Photo: Rowan Hindmarsh- (Myrtaceae) as ‘Declining’ or ‘Th reatened’—a precautionary decision taken by the Walls panel on the basis of the arrival of myrtle rust (Austropuccinia psidii), and concern 1 PLANT OF THE MONTH – PACHYCLADON CRENATUM Pachycladon crenatum. Photo: Rowan Hindmarsh-Walls. The plant of the month for June is the Fiordland Pachycladon, Pachycladon crenatum, one of 10 Pachycladon species endemic to the New Zealand region. Like most of the other mainland New Zealand species, P. crenatum is found in alpine habitats. This species can be seen in the mid to high alpine areas of Fiordland National Park, possibly spreading eastwards into the Takitimu mountains. Plants are found in cracks in rock slabs and open stony areas where there is little competition from other species. It is a small stature perennial plant, forming squat single rosettes, with a ring of short flowering stems emerging from beneath the rosette leaves. The flowers are comparatively large and white, with the fruits often turning orange. The species is most similar in appearance to P. novae-zelandiae. Both species form squat single rosettes, but P. crenatum can be distinguished by its distribution and more robust form, with larger, glossier bright green leaves. The two species may overlap on the eastern edge of P. crenatum’s range. The species is endemic to New Zealand and is currently listed as At Risk— Naturally Uncommon, because of its scattered distribution across much of central Fiordland. Being a brassica, it is likely to be very palatable so could potentially be threatened by herbivore browse, especially by hares, if they were to ever invade the central part of Fiordland; currently, they haven’t reached this area. Pachycladon crenatum could also be affected by diseases and pests such as turnip mosaic virus, aphids, white butterfly, diamondback moth, and powdery mildew, but, luckily, Pachycladon’s habitat is very far from civilisation and these pests. The species is not generally cultivated and should not be removed from the wild, since its entire range is within Fiordland National Park. The genus Pachycladon is mostly endemic to the New Zealand region, with only one species, P. radicata, being from Tasmania. It is in the cabbage family, Brassicaceae, along with other distinctive alpine genera such as Notothlaspi and Cardamine. The genus name Pachycladon means ‘thick shoot’ referring to the large stem/taproot characteristic of the genus; the species epithet crenatum refers to the crenate, or rounded teeth on the edge of a leaves. You can view the NZPCN website factsheet for Pachycladon crenatum at: http://www.nzpcn.org. nz/flora_details.aspx?ID=614 2 over the impact this rust may have/is already having on our Myrtaceae. Advice from Australian myrtle rust experts was used to arrive at this conclusion. Though myrtle rust is still in the early stages of establishment in New Zealand, already—as predicted—we are seeing an impact on the endemic myrtle genus Lophomyrtus and maire tawake (Syzygium maire), though, so far, mostly on cultivated plants or those growing in forest remnants in urban areas. The panel acknowledges that the high listing for the Myrtaceae may be inaccurate; the panel is only too happy to be proved wrong. The decision to take this step, however, accords with the precautionary principle advocated by the New Zealand Threat Classification System, and the stance already being taken by the Ministry of Primary Industries and Department of Conservation. Both agencies have been trying to obtain seed and germ-plasm of New Zealand myrtles in the full expectation that some of these iconic trees and shrubs are going to go extinct while the rest are probably going to get very sick. With no cure in sight, this is a potential disaster for New Zealand’s coast to montane vegetated ecosystems. A copy of the report is available free from: https://www.doc.govt.nz/Documents/science-and-techni- cal/nztcs22entire.pdf The NZTCS data used to compile the report may be viewed and downloaded from: https://www. nztcs.org.nz/#/reports/38 Seed banking Myrtaceae on Aotea/Great Barrier Island Emma Bodley ([email protected]) Myrtle rust is a fungal disease thought to have blown here from Australia where it is widespread. It was first detected in New Zealand in April 2017 on Raoul Island and has since spread throughout the country. It threatens the survival of our native Myrtaceae species and, with little understanding of its long term impacts on Myrtaceae species, seed banking is one way we can buy time to mitigate the potential impacts of this disease. The Department of Conservation (DOC) had a list of target species and number of collections they wanted to make but required assistance to carry of seed collection. In May 2017, a partnership between DOC and Botanic Gardens Australia New Zealand (BGANZ) was formalised with the signing of a memorandum of understanding at the Threatened Species Summit. The MOU reflects both organisations’ commitment to work together on “… Emma Bodley from Auckland Botanic Gardens mutually important plant conservation work, improving notes the locations of Metrosideros parkinsonii. co-ordination, achieving more research, increasing Photo: Bec Stanley. conservation capability and reducing costs by increasing the efficiency and effectiveness of the relationships.” Auckland Botanic Gardens (ABG) is a member of BGANZ so the opportunity arose to utilise both organisations’ expertise to work on seed banking some Myrtaceae on Aotea/Great Barrier Island. This work was supported by the The Global Tree Seed Bank Project of Millennium Seed Bank Partnership (MSB), Kew, which provided funding from the Garfield Weston Foundation. Seed collection on Aotea was supported by the MSB because of the high concentration of Myrtaceae species in Metrosideros parkinsonii seedling. Photo: Bec Stanley. 3 one place and recognising that we could contribute to the Global Tree Seed Bank Project. The canopy of the Aotea comprises Myrtaceae species with kānuka (Kunzea robusta) and pohutukawa (Metrosideros excelsa) being the dominant elements of the landscape.