To coincide with the annual National Invasive Species Awareness Week, Hawai‘i will be hosting its first ever Hawai‘i Invasive Species Awareness Week (HISAW) from March 4-10, 2013. HISAW will include events across the state to bring awareness to an issue our state legislature calls "the greatest threat to Hawaii's economy and natural environment and to the health and lifestyle of Hawai‘i's people."
What are invasives?
The term "invasive species" is used in a lot of different ways, but typically it refers to a species that is both 1) harmful to the environment, economy, and/or human health, and 2) not native to the area in which it is presenting a problem. Executive Order 13112, authorized by President Bill Clinton, defined invasive species as "alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health."
Why are they a problem in Hawai‘i?
Hawai‘i is a very unique place, due in part to its geographic isolation and volcanic origin. What we refer to as Hawai‘i's native plant and animal species are those that arrived here without the assistance of humans: seeds for Hawai‘i's first plants arrived here by floating on the waves, being blown by the wind, or transported by traveling birds. Likewise, Hawai‘i's native animal species are those that flew here on the wind or swam here on the water. Introduction events like these are very rare, and so the species that made it to Hawaii lived here in relative isolation over the 70 million years of Hawaii's volcanic history. Those original introductions spawned, through the course of evolution, native Hawaiian species that are often found nowhere else in the world. Our ‘ohi‘a and koa forests are uniquely Hawaiian, as are the hoary bats, ‘i‘iwi, and ‘apapane that once filled those forests.
Species that evolve on islands do so in the absence of some of the world's more competitive species, such as sharp-hooved ungulates, carnivorous predators, or thorny or toxic plants. Because island species do not have to defend themselves against such threats, they lose (or fail to evolve) the defensive mechanisms often found in their distant mainland relatives. The result is a relatively benign environment: the koa is a thorn-less species of the genus Acacia, distantly related to the more prickly acacias found elsewhere in the world. Likewise, birds in pre-contact Hawai‘i could nest on the ground, since they didn't have to worry about predators.
The problem, then, arises when we bring nonnative, competitive species from other parts of the world into our Hawaiian ecosystems. In today's globalized society, it's easy for humans to move species from one place to another, and this has resulted in the introduction of species such as deer, goats, ants, coqui frogs, miconia, and others into Hawai‘i. Hawai‘i's native species haven't evolved to compete and coexist with these species, and the result is that these new introductions become "invasive."
The effects of invasive species are wide ranging. Miconia, an invasive plant from South America, quickly spreads throughout forests and prevents the growth of other plants, increasing the risk of erosion with its shallow root systems. Axis deer browse on a variety of native plants and agricultural goods, and their hooves break up soil and increase erosion. Little Fire Ants infest beach parks, homes, and habitats for native species, resulting in painful stings, lost crops, and injured pets. If brown tree snakes were introduced to Hawai‘i, they could potentially cause the extinction of our native bird species, and could cost an estimated $2.14 billion a year in damages to electrical infrastructure and medical costs associated with snake bites.
What can be done?
The State and its conservation partners work hard to prevent new invasive species from arriving in Hawaii, and to control those that are already here. The public's help is greatly needed to ensure that we are minimizing the risk that invasive species pose, and that new introductions of invasive species are reported as soon as possible. Hawai‘i Invasive Species Awareness Week aims to spread the word about the threats posed by invasive species and to give people the tools and information they need to help protect Hawai‘i's unique environment and way of life.
If you'd like to learn more about some of the many programs that the State and its partners conduct to minimize the threat of invasive species, you can visit http://hawaiiinvasivespecies.org, where you'll also find information on public involvement and reporting through the Statewide Pest Hotline.
If you'd like to learn more about some of Hawai‘i's most problematic invasive species, check out the species profiles at http://hawaiiinvasivespecies.org/pests/
Questions? Contact Joshua.P.Atwood@hawaii.gov