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Global review of plant conservation on oceanic islands

7 May 2010
In a recent special issue on oceanic islands of the journal ‘Perspectives in Plant Ecology, Evolution and Systematics‘ a team of 12 island plant conservationists led by Dr. Juli Caujapé-Castells at Jardín Botanico Canario, Gran Canaria, Spain - BGCI's Spanish Office - has published a comprehensive analysis of conservation status and threat factors of oceanic island plants on a global scale.
Based on the numbers of insular endemic plants in the endangered (EN) and critically endangered (CR) IUCN categories for 53 island groups with an estimated 9951 endemic plant species, the authors estimate that at least between 3500 and 6800 of the estimated 70,000 insular endemic plant species worldwide might be highly threatened (CR+EN) and between 2000 and 2800 of them in critical danger of extinction (CR). Plant endemics from very small islands are more often critically endangered.

The authors discuss the role of seven groups of threat factors that together lead to the endangerment of island plants:
  • small population sizes and fragmentation
  • lost mutualisms
  • habitat alteration and destruction
  • invasive alien plant species
  • invasive alien invertebrates and pathogens
  • invasive alien vertebrates
  • climate change and pollution
While the effects of past threat factors are still prevailing (i.e. small population sizes, invasive species), new factors are emerging where knowledge about effects is largely missing but that likely will accelerate the loss of plant biodiversity on islands (i.e. climate change and pollution).

An upscaling of conservation measures to save island plants is urgently needed, and a global island plant conservation network should be initiated to link conservationists with similar management challenges in different regions.
The setup of such a network is currently being planned. If you are interested in the new island plant conservation network please contact Dr. Christoph Kueffer or BGCI.

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