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Founder
effect: Combination of genetic drift and natural selection
resulting in a new genetic direction for a small population
or individual in a new environment.
(Dictionary of Biology, E. Martin 1986)
My
first lesson in Hawaii was about dirt. Soil development
to be more precise. Like many who experience Hawaii for
the first time, from an airplane approach onto the Huehue
lava flow at Keahole Airport, I saw barren, black rock.
No swaying coconut trees, no Polynesian hula girls, just
a two hundred year old lava flow with a few tufts of grass
here and there. Unlike many tourists who at this point
ask, "What have we gotten ourselves into?",
I asked the naturalist's question, "What's going
on here?"
My
belongings loaded into the red, subcompact rental car,
I drove south towards a place called Hoopuloa. Moments
after merging onto the main road, Queen Kaahumanu, a new
and splendid bird hopped across my lane. With the determination
and poor driving etiquette often displayed by birdwatchers,
I flipped a U-turn and skid off the gravel shoulder. Binoculars
and bird book close at hand, my first myna was observed
and identified. Not hawaiian, I read, but a native to
India. As the drive continued south, the sparse rock land
gave way to lush urban landscape, dense agricultural plantings,
and the lush Kona forests. And still, with the image of
heat waves rising off the black rock of the airport in
my head, I wondered, "What's going on here?"
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Photo
by Jack Jeffrey |
| All
of Hawaii's native species derived from colonizers
that got here either through the air like the Pacific
Golden Plover who is an anuual visitor. Or by sea
like the Monk Seal. |
What's
going on here is colonization. Colonization by a malihini
portagee from California, colonization by an invasive
fountain grass from Africa, colonization by a bio-control
Myna from India. Colonization of the most isolated archipelago
in the middle of the world's greatest ocean.
A
couple days later upon settling in to my new niche in
South Kona, I happened along a flow of ants with a peculiarly
crazy procession. After a brief enjoyment of the chaotically
synchronized dance of the ants, I began, as a proper Western
man, to take inventory. What are they called? Are they
hawaiian ants? If not, where are they from? Did they arrive
by the United Flight 40 San Francisco to Kona direct?
(Soon enough, I found out these answers: Crazy Ant, Paratrechina
longicornis, native to New Guinea.) With my gaze focused
on the minute, I noticed the dirt. It was a small pocket
of debris nestled in a depression of chunky rock. Down
on my knees, I bowed forward for an ant's perspective.
In the small area at arms length around me was a rocky
substrate pockmarked with little islands of soil. Some
the size of my thumb, others as large as my head. Probing,
flicking and scooping, I discovered a micro-archipelago
in my front yard on the slope of Mauna Loa. The "dirt"
I caressed wasn't really dirt at all. It was a cornucopia
of organic stuff: tiny live creatures, their discarded
exoskeletons, their tiny little turds of digested materials,
earthworms, sowbugs, other little microfauna plus sand-sized
pieces of lava. The rock that held these islands of soil
was basalt lava, a piece of clinker from an a'a flow that
pushed it's way out of the southwest rift zone of Mauna
Loa in 1926--a thick vein of lava erupted down the mountainside
like toothpaste squeezed out of its tube.
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|
Photo
by Jack Jeffrey |
| Kupaoa
is a native Dubautia that is a lava colonizing plant
as is the resplendant Amau fern. |
Knees
aching from the sharp rock, I stood and inhaled an expansive
view. Life was all around me. On the young Hoopuloa flow
before me, every inch of rock was covered with growth:
lichens, ohia-lehua trees, kukaenene, ohelo, kupaoa. Farther
off was the jungly growth of guava and christmas berry
broken by the cultivated gardens of housesites and macadamia
nut orchards. All of it, I realized, grew from barren
lava like that at Huehue. The grayish, sunbleached trunks
of the eighty-foot high ohia-lehua trees, which formed
a long mauka-makai line on undeveloped state land in the
distance, began in the little pockets of debris from colonizers--these
founders of the flow at my feet.
In
a view from my toes to the not too distant tree tops,
a lesson lay about me. Life took hold in a place where
magma gases once occupied. The little burst pockets of
vapor in the lava provided a niche for organisms to colonize,
grow, devour, defecate, die and decompose. The debris
of these colonizations together make soil, so that one
day a forest, an orchard, a taro patch, may occupy the
hard rock of the volcano. As this lesson sifted into the
cracks and crannies of my mind, I wondered what life would
sprout from the debris of my colonization on Hawaii? What
will be my founder effect?
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