Local plants added to at-risk list
By Jan TenBruggencate
Advertiser Science Writer
The World Conservation Union has added 125 Hawaiian plants to its list of species worldwide that are threatened with extinction.
Since last year, the conservation union added 2,000 species to its updated Red List of Threatened Species, released yesterday. The list now totals 12,000.
The fast growth in the number of species that risk extinction is a particular issue on islands, and competition from invading alien plants and animals is one of the primary causes.
Bishop Museum entomologist Frank Howarth said islands have special risks.
"Two principal factors are the isolation and that the areas are so small. On the continents, if something winks out in one location, it usually survives in several others, but on islands there may be fewer so-called refuge habitats," Howarth said.
When humans show up and bring with them a host of new plants, animals and insects, the native island biology suffers.
"Island populations of native plants and animals are being lost through the effects of invasive alien species, which are a major threat to global biodiversity," the World Conservation Union said.
The formal name of the Switzerland-based group is the International Union for Conservation of Nature and Natural Resources. It collects data from thousands of scientists worldwide. The organization's goal is to provide a global index that governments can use to guide their conservation efforts. The list already contained many Hawai'i species, including forest birds, turtles and other species.
It describes a steamroller effect of attacks on native species by alien insects, competition from foreign weeds, the loss of the insects and birds that pollinate the plants, and the loss of habitat to development.
In a statement associated with the updated Red List, the group cites a critically endangered West Maui shrub with hairy stems, Hesperomannia arbuscula, whose survival is threatened by rooting pigs and munching rats, competition by the Florida blackberry and the invasive pest clidemia, and whose roughly 25 surviving representatives are at risk of being trampled by humans.
And it's not only plants at risk. The organization also cited the threat to the Kaua'i stream snail known as Newcomb's snail, which recently was placed on the federal endangered species risk list.
"A variety of intentional and unintentional introductions of non-native fish, snails, flies and frogs threaten its survival," the group said.
"While we are still only scratching the surface in assessing all known species, we are confident this figure is an indicator of what is happening to global biological diversity," said director general Achim Steiner.
One-quarter of all mammals and one-eighth of all birds are at risk of extinction, and there have been notably fast drops in numbers of reptiles and primates.
The union has a searchable database online at www.iucnredlist.org.
Reach Jan TenBruggencate at jant@honoluluadvertiser.com or (808) 245-3074.
