New Zealand collections of <i>Rhododendron</i> as a resource for ex situ conservation

This study uses <i>Rhododendron</i> L. collections in New Zealand to analyse the contribution of introduced species in cultivation to global ex situ conservation. Living botanical collections of Red List taxa are the fundamental resource that enable ex situ conservation, and Target 8 of the Global Strategy for Plant Conservation requires 75% of Red List taxa to be in ex situ collections by 2020. We compared <i>Rhododendron</i> taxa (species, subspecies, botanical varieties) in New Zealand with the range of taxa in international cultivation, and determined the presence of taxa from Red List categories, geographic origins and taxonomic groups. The 566 taxa in New Zealand, including 224 Red List taxa, encompass 67% of the taxa in cultivation worldwide, ranking second internationally for number of taxa in the collections investigated. New Zealand holds wild-collected material of 230 taxa, including 70 Red List taxa, and 20 taxa for which wild material is not listed in the international collections studied. China is the geographic origin of the greatest number of <i>Rhododendron</i> Red List taxa held in New Zealand. Of the 77 taxonomic subsections of <i>Rhododendron</i>, New Zealand holds 75% or more of the taxa in cultivation for 37 subsections, and 75% or more of the Red List taxa in cultivation for 24 subsections. The greatest numbers of Red List taxa in New Zealand collections are from section <i>Rhododendron</i> subsection <i>Maddenia</i> (20) and section <i>Pontica</i> subsection <i>Neriiflora</i> (17). Our analysis enables us to (1) propose conservation action for <i>Rhododendron</i> in New Zealand, (2) summarise our approach as a model for examining other introduced plant genera in New Zealand, and (3) propose our method as a component of an ex situ conservation strategy for New Zealand.本研究以新西兰境内的杜鹃花属（Rhododendron L.）栽培馆藏为研究对象，分析栽培归化物种对全球迁地保护（ex situ conservation）的贡献。红色名录类群（Red List taxa）的活体植物馆藏是开展迁地保护的核心资源；《全球植物保护战略》（Global Strategy for Plant Conservation）第8项目标要求，至2020年需将75%的红色名录类群纳入迁地保护馆藏。本研究对比了新西兰境内的杜鹃花属类群（含物种、亚种、植物学变种）与全球栽培杜鹃花属类群的范围，并从红色名录等级、地理起源及分类类群三个维度，明确了各类群的馆藏保有情况。新西兰馆藏的566个杜鹃花属类群（含224个红色名录类群）覆盖了全球栽培类群的67%，在本次调研的馆藏类群数量上位列全球第二。新西兰馆藏包含230个类群的野生采集材料，其中70个为红色名录类群；另有20个类群的野生材料未被纳入本次调研的国际馆藏名录中。新西兰馆藏的红色名录杜鹃花属类群中，起源于中国的类群数量最多。在杜鹃花属的77个分类亚组中，新西兰馆藏覆盖了37个亚组75%及以上的栽培类群，以及24个亚组75%及以上的栽培红色名录类群。新西兰馆藏红色名录类群数量最多的类群隶属于杜鹃组（Rhododendron）马银花亚组（Maddenia，20个类群）及Pontica组Neriiflora亚组（17个类群）。本研究的分析结果可实现三大目标：（1）为新西兰境内的杜鹃花属物种制定针对性保护行动方案；（2）总结本次研究方法，将其作为新西兰境内其他归化植物属类调研的示范模型；（3）将本研究方法作为新西兰迁地保护战略的组成部分予以推广。