Biology Reference
In-Depth Information
We started to see clusters of 'i'iwis and a number of 'apapanes, the other red nectar-
feeding honeycreeper. Along the way, Jack pointed out a tall, familiar-looking plant with
large greenish-purple curved flowers. It was a lobelia—related to the cardinal flowers Amer-
ican birders grow to attract hummingbirds. This was no common cardinal flower, though, but
one of the rarest plants on Earth.
Clermontiapyrularia
had nearly gone extinct, but Jack and
his colleagues had managed to rescue it. Now this species and other lobeliads are propag-
ated and transplanted back into the wild. Jack and his colleagues are focusing the same kind
of intensive restoration efforts on some rare mints that Jack discovered. Some of the other
honeycreeper-pollinated plants, like the lobelias, are now imperiled because they have lost
their pollinators and must be handpollinated in the field to keep the populations alive.
When I asked Jack about restoration of Hawaiian silverswords, his eyes lit up. Sil-
verswords, which take their name from the long, narrow leaves and silvery hairs found on
most species, are a Hawaiian rarity that some plant conservationists have devoted their lives
to saving. These plants can live to be fifty years of age, show remarkable adaptations to cope
with rarity, and have an odd life cycle, waiting until the end of their life to send up a flowering
stalk and then fruit before dying. Silverswords, which also go by the far less poetic name of
tarweeds, belong to the genus
Argyroxiphium
, a small group of five species in the sunflower
family. But like the honeycreepers, silverswords radiated into an array of more than thirty
species. This group is known as the silversword alliance, a brother- or sisterhood of plants ad-
apted to living under extremely harsh conditions—under the volcano and on its cinder fields
or in acid swamps known as bogs. How could plants that survive the tough life in the shad-
ows of volcanoes, exposed to wind and freezing temperatures and desiccation from intense
sunshine, and those that thrive in bogs and in such low-nutrient soils, have become so rare?
Volcanoes and bogs should be the boot camps for rare plants, toughening them up and allow-
ing them to resist any disaster, manmade or natural. Silverswords even show peculiar adapt-
ations enabling them to raise their body temperature by focusing sunlight on the shoot tips.
What they are not adapted to is the trampling of pigs and browsing of goats that have been
introduced here. Their thinly buried roots, especially those of the bog-loving species, are eas-
ily destroyed, and their succulent leaves are prime delicacies for goats.
Even before humans arrived on the islands, all species of silverswords had very limited
ranges, and they remain vulnerable to extinction. Some populations are quite numerous, such
as the Haleakala silversword, found only in an old crater on Maui. Its entire global distribu-
tion is limited to this one site, but this tiny area supports more than 40,000 individuals. Yet
however common this species of silversword may be locally, all its eggs, or seeds, are in this
one basket. Lose this site to pigs and goats and you lose the species forever. Jack and his
colleagues, in addition to being botanists, have become world-class fence builders and goat
rustlers, courses never taught in the ivory tower but essential to study and save rarities in the
wild.
