Conservation of four rare, endemic and iconic Fijian tree species
A project undertaken at the Department of Environmental and Aquatic Sciences, Curtin University of Technology, and supervised by Gunnar Keppel.
Anthropogenic disturbance has resulted in large-scale conversion of natural vegetation to fragmented landscapes. This is placing strain on ecosystems and their resident flora and fauna. Protecting biodiversity in degraded landscapes is one of the major challenges facing biologists and naturalists. This challenge is complicated by the forecasted changes in climate, fuelling fears for an environmental disaster and extinction crisis. Islands are considered especially vulnerable.
Fiji is a biodiversity hotspot of high conservation priority. Its considerable age (about 40 million years) and isolation have resulted in a diverse flora with high endemism. Nevertheless, the flora remains poorly explored, illustrated by the discovery of new species and forest types in Fiji. Knowledge gaps are especially prevalent in the ecology, genetics and conservation of plant species. There exists little data on the ecology or population genetics of Fijian plants and the IUCN redlist states that 97% of the 70 threatened terrestrial plant species need updating.
In this project, we use a multi-disciplinary and multi-institutional approach to assess the conservation status to efficiently mitigate the effects of impeding climate change for four iconic IUCN red-listed tree species endemic to Fiji: Cynometra falcata (Caesalpinaceae; IUCN red-list status: critically endangered), Dacrydium nausoriense (Podocarpaceae; endangered), Degeneria vitiense (Degeneriaceae; Vulnerable), and Podocarpus affinis (Podocarpaceae; vulnerable). We will use data from population genetics, species distribution modelling (SDM), systematic threat assessment, ecological surveys and local knowledge to identify the anthropogenic, ecological, environmental and genetic conservation threats for each species and use this data to revise their IUCN status and design effective conservation plans, which will be implemented through consultation with government and landowners. The specific objectives and preliminary results species are as follows:
- Use known distribution records (e.g., herbarium records) to determine the actual distribution using SDM and subsequent field surveys.
Existing distribution records for the four rare tree species have been digitised and relevant topographic and climatic GIS layers obtained. Conducting meaningful SDM has not been possible because: a) only a few (3-7), geographically highly restricted (< 1km2) populations remain for each species, providing less than 10 data points; b) existing climate models are too coarse-grained to provide data at ecologically and geographically relevant scales; c) climatic data for most of the interior of the bigger islands is extrapolated from mostly coastal climate stations.
- Estimate genetic diversity, genetic connectivity, possible hybridization, and fine-scale genetic structure.
Genetic parameters can provide important data to conservation strategies for endangered plants, such as the amount of genetic diversity, connectivity of populations, the occurrence and direction of hybridization, and the genetic distinctiveness of a taxon. This population genetic information can be particularly relevant, if a common congener is available for comparison. We have collected genetic samples of 30 individuals each from 3-7 populations per species. These samples are being analysed using microsatellites and/or next-generation sequencing at the Queensland University of Technology.
- Determine the basic ecology of each rare species.
Basic ecological data collected include dbh, density and regeneration. These data will be supplemented with seed and pollen dispersal data, which can be estimated from the molecular data. Populations visited so far appear to be healthy, show L-shaped size structure curves and abundant regeneration.
- Systematic assessment of local conservation threats facing each population.
Local conservation threats for each population are being assessed by answering, through observation and discussions with local landowners, a set of questions pertaining to existing protection and to existing and potential threats.
- Design effective conservation measures that incorporate predicted changes in climate and local economic, political and social dynamics.
Data obtained from conservation biology, ecology, genetics and geography component of this project will be combined to provide a good foundation for effective conservation planning.
- Make findings widely available
So far the following publications and presentations related to this project have eventuated:
Keppel G, C Morrison, D Watling, MV Tuiwawa & IA Rounds (2012) Conservation in tropical Pacific Island countries: why most current approaches are failing. Conservation Letters 5:256-265.
Keppel G, C Morrison, J Hardcastle, IA Rounds, IK Wilmott, F Hurahura & KS Patterson (2012) Conservation in tropical Pacific Island countries: case studies of successful programmes. PARKS 18:111-124.
Keppel G, P Prentis, E Biffin, PD Hodgskiss, S Tuisese & AJ Lowe (2011) Speciation and hybridisation dynamics in a recent radiation of Pacific Dacrydium and implications for conservation. Australian Journal of Botany 59: 262-273.
Keppel G & D Watling (2011) Ticking time bombs - current and potential future impacts of four invasive plant species on the biodiversity of lowland tropical rainforest in south-east Viti Levu, Fiji. South Pacific Journal of Natural and Applied Sciences 29 (in press).
Keppel G & KP Van Niel (2011) Habitat loss and climate change refugia in four threatened and endemic Fijian tree species. International Congress for Conservation Biology, 5-9 Dec 2011, Auckland, New Zealand.
Gunnar Keppel (University of South Australia), Peter Prentis (Queensland University of Technology), Dick Watling (NatureFiji-MareqetiViti), Grant Wardell-Johnson (Curtin University), Kimberly Van Niel (University of Western Australia), Bob Pressey (James Cook University)