Photo credit: phys.org
Australia is home to over 8,000 continental islands, many of which remain untouched and uninhabited. These islands serve as critical sanctuaries for numerous species, offering protection from the various dangers present on the mainland.
The coastal islands of Australia are also significant for researchers investigating how plant communities establish themselves in new environments and evolve over time.
In response to this need for data, a new open-access database named A-Islands has been established, compiled from decades of detailed plant surveys conducted by botanists across Australia.
This extensive database encompasses information about over 6,500 different plant species across more than 850 islands. The islands vary greatly in size, from those spanning several kilometers to others as small as a single apartment.
An article detailing this new research, published in the Journal of Vegetation Science, reveals fresh perspectives on the transformation of Australia’s coastal islands over the years. This resource is envisioned to aid in ongoing plant monitoring and conservation initiatives, especially in light of the challenges posed by climate change.
Challenging Expeditions for Data Collection
The creation of A-Islands involved meticulously digitizing existing botanical survey data from historical texts and engaging with botanists and organizations throughout the country.
The database comprises 1,350 botanical surveys from various islands, dating back to the 1940s and originating from over 135 different sources. Notably, this collection continues to expand.
Many stories emerge from the data collection efforts, with some botanists camping on remote islands for extended periods to ensure comprehensive documentation of all living plants encountered. Others navigated steep cliffs via small boats or even parachuted from helicopters to reach isolated islands for their surveys.
The Biodiversity of Australia’s Coastal Islands
As analysis of the surveys progressed, it became evident that Australia’s coastal islands host an impressive array of species diversity. Though these islands encompass less than 1% of the nation’s terrestrial area, they are home to at least 25% of Australia’s plant species.
The climates of these islands are remarkably varied, ranging from tropical coral atolls in Queensland to the harsh, frigid conditions of the rocky outcrops near Tasmania.
While some plant species can be found on numerous islands, the majority are localized to just a select few, forming essential plant communities that underpin the islands’ ecosystems and provide vital habitats for many endangered animal species.
Longitudinal Data Benefits
Notably, many islands included in the A-Islands database have been surveyed multiple times throughout the last century. This is significant as most ecological studies typically provide only a one-time snapshot of a location’s biodiversity.
In contrast, A-Islands offers insights into how plant communities have evolved over decades. Such long-term ecological data is uncommon but crucial for enabling scientists to forecast future changes in vegetation due to ongoing climate shifts.
A Dynamic Perspective on Species Communities
Common assumptions about plant communities often depict them as static entities. However, the A-Islands project highlights that on these coastal islands, species are in a constant state of flux. Species from the mainland migrate to the islands, establish populations over time, and eventually face extinction, only to be succeeded by other species. This ongoing process is termed species turnover, which suggests that while individual species may change, the overall diversity within the community tends to remain stable over longer periods.
Interestingly, the dataset indicates that some species undergo turnover more swiftly than others. For example, grasses and small herbs are more prone to disappear and reappear than longer-lived, larger species.
Islands as Future Climate Sanctuaries
The A-Islands dataset will be increasingly vital as climate change intensifies. Islands are particularly susceptible to biodiversity risks, with more than half of all global plant extinctions having occurred in these isolated systems.
Pinpointing trends in how species communities transition will be essential for forecasting how plants everywhere may react to climate change in the future. Coastal islands may serve as critical refuges, offering a buffer against extreme temperatures due to their surrounding ocean environments, thereby safeguarding diverse plant species.
Additionally, the A-Islands database serves as an invaluable reference for establishing historical baselines of species that have existed in these relatively untouched ecosystems. It will also guide researchers in prioritizing future surveys as climatic conditions evolve.
Source
phys.org