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BioNET-INTERNATIONAL

Why taxonomy matters
A series of case studies highlighting Taxonomy's Value to Society
www.bionet-intl.org/case_studies

Implementing the Global Taxonomy Initiative of the CBD
CASE STUDY 15
Biological control the only feasible solution to costly alien invasion

Relevant Sector: Invasive alien species; biological control

Geographic Location: Hawaiian Islands

Problem Statement: Among the many species introduced to the Hawaiian Islands, Myrica faya (the fire tree) is an evergreen shrub or small tree which is ranked as one of the most noxious invasive species in the archipelago. The species is an active actinorrhizal nitrogen-fixer capable of invading nitrogen limited, early successional sub-montane rainforests, which are naturally open-canopied ecosystems. Myrica quadruples the nitrogen input into the soil and thus radically modifies the nitrogen dynamics of early successional ecosystems, facilitating further invasion. In addition, Myrica disrupts native community dynamics through shading out understorey species.

Methods: Taxonomic expertise and knowledge allows for monitoring the distribution of the species and the ecological changes in the surrounding flora. Control methods have proven elusive, however. Physical removal as well as chemical control has proven to be unfeasible. Biological control mechanisms are presently being tested.

Outcomes and Impacts: It is hoped that taxonomy and other techniques will enable identification of appropriate management strategies for a problem that involves enormous economic, environmental and other costs.

Lessons: While species introduction has been an integral part of the history of human migration and settlement, invasions of key species should be closely monitored and managed where required, especially in very vulnerable systems such as island and other geographically isolated ecosystems. This is dependent on the appropriate taxonomic expertise being available.

Reference: Biosphere reserve e-fact sheets <http://www2.unesco.org/mab/br/brdir/directory/biores.asp?mode=all&code=USA+32>

Contact Information: Haleakala National Park, P.O. Box 369, HI 96768 Makawao, Maui, United States of America. Tel: +1808 572 44 00. hale_superintendent@nps.gov