Germplasm Collection, Storage and Reintroduction: Important Aspects of an Integrated Strategy for the Conservation of Threatened Flora in Western Australia
Anne Cochrane and Leonie Monks
WA Herbarium, CALM Science Division
Department of Conservation and Land Management
Home | Contents | Introduction | Recovery Plans | Threatened Flora Seed Centre (TFSC) | Translocation | Case Study | Site Selection and Translocation Design | Monitoring | Conclusions | References | Acknowledgements | Figure 1: Monitoring Seed Viability in Long-term Storage | FIGURE 2: Neis genetic distance for populations of L. orbifolia.
The South West Botanical Province of Western Australia has one of the most genetically diverse floras in the world, with over 12,000 taxa. Loss of habitat, weed invasion, salinity and dieback disease are major threating processes to native plant survival. More than 2000 taxa are considered under threat from one or several of these processes, with nearly 100 of these taxa listed as critically endangered. Loss of populations and substantial reduction in population size may not necessarily lead to immediate species extinction, but inevitably results in loss of genetic diversity. Genetic variation enables plants to adapt to changing environmental and ecological conditions, as well as providing resistance to pests and disease, and is critical for the long term survival of most species.
The Western Australian Threatened Species and Communities Unit (WATSCU) of the Department of Conservation and Land Management (CALM) is responsible for the development of Flora Recovery Plans (RPs) which aim to outline the recovery actions required to address the threatening processes affecting the ongoing survival of critically endangered flora in Western Australia. In addition to detailing the background of each of the targeted taxa, the threatening processes, the recovery objective and criteria for success/failure, RPs list the recovery actions required to ensure that the taxon is given the best possible chance for survival in the long term. This involves the monitoring of existing populations, surveys for additional populations, the development of appropriate fire management plans, and conducting research into the biology of the taxon. An essential part of the recovery process also involves the scientific management of ex-situ collections, and their recovery and re-introduction into managed environments.
Part of this integrated strategy for the conservation of rare and threatened plant species is the establishment and maintenance of a genebank, or long term storage facilities for genetic material. Genebanks can be used as an interim solution to prevent the loss of genetic diversity or as a last resort in preventing the extinction of the species. One of the most cost effective methods for genebanking in plants is the long term storage (ie., a minimum of 50 years) of seed at low (-20oC) temperatures.
The TFSC was established in 1992 by CALM with the principal objective being to ensure the maintenance of genetically representative seed collections of threatened flora under long term (>50 years) storage conditions (Cochrane, Kelly and Coates 1996). Ex situ collections can supply opportunities for scientific study and provide the basis for future population re-establishment. Genebanks can be seen as a step to the recovery of a species rather than an end in themselves
Seed collection of rare and threatened flora is conducted on a provenance basis, with the aim of gathering at least 70-80% of the genetic diversity of each taxon. Seed is collected from up to 5 populations of each taxon with 10 to 50 or more individual plants represented within each population. A minimum of 1000 viable seed per population should ensure sufficient material for the initiation of a translocation programme should it be required. All seed collections are vouchered at the Western Australian Herbarium in Perth.
Seed is stored at low moisture content (~5%) and at low temperatures (-20oC) in hermetic containers (heat sealed laminated aluminium foil). The viability of seed is monitored on a regular basis by conducting standard germination tests. Results to date indicate that a wide range of taxa respond well to storage at -20oC (Figure 1). The products of these germination trials are provided to Perths Kings Park and Botanic Gardens (KPBG). Other germinants are assessed for their susceptibility to Dieback disease (Phytophthora spp.) by CALM scientists. A comprehensive database (WASEED) incorporating information on seed origin, history since collection, germination requirements and response to storage has been established and allows for easy access to information on each taxon.
Translocation is the term given to the transfer of genetic material from one site to another, whether existing (reinforcement), extinct (reintroduction) or new sites (introduction). The process of translocation requires careful planning, the establishment of specific guidelines and long term commitment to monitoring. The aim of translocation projects is to establish self sustaining populations with a broad genetic base to ensure the potential for adaptation.
In 1997 CALM commenced the first of a series of experimental translocation trials. These experiments include the cooperation of the botanic gardens and community groups (recovery teams). A total of ten critically endangered taxa are being targeted for translocation over the lifespan of the project. Seven were selected for translocation in 1998. This is the first time that a large scale systematic approach to plant translocations has been undertaken in Western Australia. The ultimate aim of this project is to develop and implement protocols for the establishment of viable populations of a range of taxa. The seed resources of the TFSC are being utilised to provide a broad genetic base for the re-establishment of these new populations. The resulting seedlings are being raised by KPBG, under strict hygiene conditions.
Lambertia orbifolia (Proteaceae) is known from two locations, Augusta and Narrikup, separated by some 200 km. It is a non-lignotuberous shrub to 3 metres with erect and spreading branches. Leaves are opposite, sessile and rounded in shape. Four to six orange-red, hairy, tubular flowers form the inflorescence. Flowering occurs all year with summer and winter peaks.
Considerable research has been conducted on the conservation biology and management of this taxon and has been compiled by Obbens and Coates (1997). Results from electrophoresis studies have shown a level of genetic divergence (Nei>0.2) between the two localities that often indicates a species level difference (Figure 2). However, there are no morphological differences between plants at the two localities, so under the present legislation the species is not considered to be critically endangered. The Narrikup form of L. orbifolia is known from two narrow degraded road verge populations totalling 169 individuals. Dieback disease and aerial canker, and frequent disturbance due to road maintenance activities threaten both populations. Because of the numerous threats translocation of this form was considered to be a high priority.
Three main criteria were considered prior to site selection. Proximity to the known populations, security of tenure and similarity of biotic and abiotic features to the known populations. For L. orbifolia a conservation reserve less than 4 km from both known populations at Narrikup was chosen. The site had similar white sands over laterite and open low woodland with numerous associated species in common with the known populations.
Good experimental design is essential so that results can be attributed to certain establishment techniques. Site replication is important and a range of treatments should be included. Six month old seedlings of L. orbifolia were planted in five grids (replicates) of 13m by 4m. Four treatments were chosen: control, mulched, shaded or gro-cone. Each grid was planted with 52 seedlings, in four rows. A row contained 13 of each treatment. Grids were fenced to prevent herbivore predation of plants.
Monitoring is one of the most important aspects in translocation design and requires long-term commitment. Monitoring of the L. orbifolia translocation will include counting the number of surviving seedlings, growth measurements, reproductive state, number of flowers and fruit, presence of second generation plants and plant health. Bimonthly monitoring of existing populations, in conjunction with translocation monitoring, will provide essential baseline data for assessing the performance of the new population.
This case study illustrates the depth of knowledge required for effective conservation. This involves identifying and addressing threats, determining genetic distinctiveness, and understanding population biology, seed biology, propagation and pollination mechanisms of the targeted taxon.
This multidisciplinary approach to threatened plant conservation that characterises integrated conservation strategies shows great promise for the protection of biological diversity in the future.
Cochrane, A., Kelly, A. and Coates, D. (1996). Banking for the Future. LANDSCOPE Winter 11(4), 49-53.
Obben, F. and Coates, D. (1997). Conservation Biology and Management of Endangered Lambertia Species. Project No. 443. Final Report submitted to the Commonwealth Threatened Species and Communities Section, Biodiversity Group, Environment Australia. CALM, Perth WA.
Monks, L., Coates, D. and Hickman, E. (1998). Translocation Proposal for Lambertia orbifolia (CGardner) (Proteaceae). CALM, Perth WA.
Funding for the TFSC and Translocation project has been provided by Threatened Species and Communities Section, Biodiversity Group, Environment Australia. CALM staff provided assistance in the field. A range of people have given expert advice, in particular Dr. David Coates (CALM).
Copyright 1999 NBI