Saving rainforests in the South Pacific: challenges in ex situ conservation

Abstract

Abstract. Rainforests in the South Pacific hold a considerable amount of plant diversity, with rates of species endemism >80% in some countries. This diversity is rapidly disappearing under pressure from logging, clearing for agriculture or mining, introduced pests and diseases and other anthropogenic sources. Ex situ conservation techniques offer a means to limit the loss of plant diversity. Seed banking is considered the most efficient and cost effective of these techniques but is applicable only to seed capable of tolerating desiccation and cold storage. Data on the degree of tolerance of these conditions was lacking for more than half of the 1503 South Pacific rainforest genera examined for this review. Of the 710 genera for which data were available, the storage behaviour of 324 was based on an assessment of only one or two species, although 76% of those genera contained at least 10 species. Many of the unstudied or poorly studied genera are shared across several South Pacific nations, providing an excellent opportunity for collaboration on future ex situ research and conservation. Of the 386 genera for which three or more species have been studied, 343 have a very high proportion of species (>95% of those tested) that are suitable for seed banking. Seed banking could therefore provide a suitable means for preserving a large proportion of the rainforest flora before it becomes extinct in the wild. Alternatives for preserving species that are not suitable for seed banking are also discussed.

Current issues in plant cryopreservation and importance for ex situ conservation of threatened Australian native species

“…In some taxa, the embryonic axis has the capacity to survive rapid desiccation even though the whole seed is sensitive to drying (Normah and Makeen 2008). In other taxa, the axis may be just as sensitive to drying as a shoot tip (Pammenter and Berjak 2014;Sommerville et al 2017).…”

Seeds at the forefront: synthesis of the inaugural National Seed Science Forum and future directions in Australian seed science

“…For species unsuited to seed banking, alternative techniques, such as tissue culture or cryostorage, which often rely on seeds as the initial source of tissue, are being used or further developed (Ashmore et al 2015). The paper by Sommerville et al (2017), Saving rainforests in the South Pacific: challenges in ex situ conservation, reviews the seed conservation status of a high priority ecosystem, namely the rainforests of the South Pacific. While smaller in size than the well known rainforests of the Amazon and South-East Asia, the rainforests of the countries and territories of the South Pacific, including Australia and New Zealand, are significant and biodiversity rich in species number and endemism, reflected in the 6 biodiversity hotspots across the region (Mittermeier et al 2011).…”

“…The paper provides a useful definition of the spectrum of rainforest types found across the region and an analysis of the extent of historical loss, including the recent acceleration of rainforest destruction. Sommerville et al (2017) used a range of authoritative sources, and the results of papers presented by the authors at the National Seed Science Forum, to capture the seed storage behaviour of 1503 genera from 209 families occurring in rainforests across the region. The major finding of this analysis is the lack of information on seed storage behaviour for around 50% of the genera and 25% of families examined, which is likely to be hampering effective ex situ conservation.…”

“…Although not all South Pacific countries were able to be included in this review, the work constitutes the first census of seed conservation potential of rainforest species of the region and provides a framework for future data synthesis that may expand beyond just the rainforest taxa and into other endemic or significant species of the region. The work of Sommerville et al (2017) is an important decisionmaking resource for the major integrated conservation efforts and partnerships required for rainforests in the region, which generally lack adequate conservation facilities.…”

Conservation in the wake of myrtle rust – a case study on two critically endangered Australian rainforest plants

“…Given the level of threat to both species in the natural environment, ex situ conservation of any remaining genetic diversity was seen to be imperative; however, no information was available on the suitability of the few seeds available for seedbanking (Sommerville et al 2017;Royal Botanic Gardens Kew 2019) and there were no published accounts of techniques to propagate the species by cuttings or tissue culture. To remedy this lack, and in anticipation of official recognition of the species as threatened, the Australian PlantBank (PlantBank) began developing tissue culture protocols for R. rubescens in 2013 using material from a single gardengrown specimen.…”