A project undertaken at the Curtin University, the University of South Australia, Queensland University of Technology and NatureFiji-MareqetiViti, and led 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.
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.
- Estimate genetic diversity, genetic connectivity, possible hybridization, and fine-scale genetic structure.
- Determine the basic ecology of each rare species.
- Systematic assessment of local conservation threats facing each population.
- Design effective conservation measures that incorporate predicted changes in climate and local economic, political and social dynamics.
- Make findings widely available
1. Species Distribution Modelling: Although existing distribution records for the four rare tree species were digitised and relevant topographic and climatic GIS layers obtained, 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.
2. Genetic Analyses: We have collected genetic samples of 30 individuals each from 3-7 populations per species. Detailed phylogenetic analyses using large scale cpDNA data derived from next generation sequencing have been completed at the Queensland University of Technology. The results from this study suggest that all the fours species pairs are taxonomically distinct and that the two Podocarpus species are only distantly related. This next generation sequencing data has also been used to develop DNA sequence-based and microsatellite markers, which have been optimized for all species. DNA has been extracted from individuals for all species and PCR and genotyping is currently in progress for all species pairs.
3. Ecology of 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.
4. Systematic Assessment of Conservation Status: The revision of the conservation status of three target species and the endemic, critically endangered conifer Acmopyle sahniana has been completed based on ecological data and conservation threats. A paper detailing these results has been submitted. We discovered new populations for all species and obtained reliable estimates of population size for the first time. As result, the conservation status of Cynometra falcata is proposed to be ‘downgraded’ from critically endangered (CE) to Endangered (EN). The conservation status of the fourth target species, Degeneria vitiensis, will be revised once detailed molecular data is available.
5. Impact of Invasive Species: An escaped population of the introduced ornamental palm Pinanga coronata was discovered in a forest reserve during data collection. This species forms dense, mono-dominant ground cover, potentially preventing regeneration of native species. In addition, Dacrydium nausoriense in the Nausori Highlands is impacted by multiple invasive plant and animal species. This led to a publication highlighting threats posed by invasive plant species to Fiji’s native flora (see below) and the development of a research proposal to develop a better understand of the ecology of invasive plant species and to eradicate existing naturalised Pinanga coronata populations.
6. Success of Conservation Projects in the Pacific: Visits to Fiji as part of this project produced stimulating discussions with conservation practitioners about differences in conservation planning and implementation in developing Pacific Island nations compared to developed nations. The thoughts and outcomes of these discussions were articulated in two papers (see below) that will hopefully assist in more effective conservation approaches in the Pacific and developing countries throughout the world.
7. Implementation of Conservation Findings: The outcomes of the conservation assessments of the target species indicate that species in the more contiguous wetter zones of Fiji are relatively well protected, while species of forest remnants in fragmented, seasonally dry habitats are not. This suggests that current conservation plans need to be revised to give greater priority to drier habitats.