February 2010. Pest escapes from botanic gardens. A member from the Royal Botanic Gardens Melbourne asked about important diseases in the Asia and Pacific region in preparation for a workshop with colleagues from other botanic gardens.
There were replies from the Pacific Island Ecosystems at Risk (PIER). This has information on invasive plant species in the Pacific region (and also considerable information on Pacific Rim countries and Indian Ocean islands as well). Quite a few invasive plants have been introduced to the Pacific region via botanic gardens, including the most notorious invasive plant in the region, Miconia calvescens, which has devastated the forests of Tahiti and is a major problem in Hawaii. You can access the site at http://www.hear.org/pier/. A sister site, Hawaiian Ecosystems at Risk (HEAR), covers Hawaii (http://www.hear.org/).
There are now tools, such as the weed risk assessment processes now being used in Australia, New Zealand, Hawaii and elsewhere that can mitigate risks:
The ???escape??? of the weed, Miconia calvescens, from several botanic gardens in Hawaii, was given as an example.
But it is not only plants that escape from botanic gardens. A good example of an insect pest escaping from a botanic garden is the Asian cycad scale, Aulacaspis yasumatsui. This scale insect was discovered at a botanic garden in Miami shortly after cycads were imported from Thailand. It quickly escaped into surrounding gardens and nurseries, and this population is the suspected source of cycad scale infestations in Hawaii and Micronesia. Here on Guam, a very severe infestation of this scale has killed between 60% and 90% of the endemic cycad, Cycas micronesica.