I’m currently fascinated
by organisms that create conditions conducive to life for other organisms. Ecologists
call them ‘keystone species,’ but I like the term 'ecosystem engineers.' These aren't
creatures that are merely content to explore a little niche in their
backyard. These are species that discover radically new ways of doing business,
blow the roof off their ecosystem, and provide all kinds of opportunities that
weren’t there before.
Often, this
inventive organism will bloom into a flowering ‘radiation,’ expanding unchecked
into new habitats and diversifying into multi-forked branches of exquisitely
perfected species. Other species come along, using their ‘waste’ as a source of
new creation.
Beaver Dam |
Big as a Black Bear! |
In the Pleistocene,
another ecosystem engineer was at work. A huge variety of elephants, large,
small, woolly, bald, even one with a spork, were instrumental in creating the
savanna-grassland patchwork we see in parts of Africa, Asia, and the Americas.
Uprooting trees, decimating forest edges, ancient elephants provided clearings
for grassland to spread. Grazers benefitted, and so did our own ancestors. We
also see elephants excavating dry riverbeds with their tusks, creating wallows
essential to other species in the long dry season.
from Elephants: A Cultural and Natural History |
Forest before Elephants |
Forest After Elephants |
Other ecosystem
engineers include towering ancient fig trees, offering substrates and habitats
for countless tropical epiphytes, insects and spiders, birds and primates,
lichens, and various rainforest mammals. Coral reefs teem with life, generating
a jaw-dropping richness of endless jewel-like diversity.
Old fig tree with his friends, T. Woolley-Barker |
And
what about our atmosphere? Here’s where it gets really interesting. I recently
visited a strange, salty, axolotl-filled volcanic lake in the mountains of Mexico.
The shore was ringed with rounded, bleaching humps that looked for all the
world like enormous decaying brain corals. It turns out these ‘stromatolites’
are the calcified byproducts of ancient photosynthetic bacteria that created
our planet’s atmosphere
3.8 billion years ago. They are still at work today in a few isolated spots.
Thanks to them, we have air to breathe, and a nice cushy ozone layer, which
blocks out most of the UV light, allowing us (and many other species) to live on
land. Their gift to us also transmits water vapor, burns up meteors, and keeps
us warm. Thanks, stromatolites!
In each of these
systems, a single, radical adaptation changes the world, making the whole much greater
than the sum of its parts, and the ecosystem much richer than a random jumble
of species. But what about humans? Surely we are the ecosystem engineer par excellence? We are rapidly changing the composition of the
atmosphere, the temperature and weather patterns of the Earth, adding polymers
that never before existed, bringing vast quantities of metals to the planet
surface, cutting and burning forests, paving surfaces, and modifying every
environment to suit ourselves. That’s our radical invention: we can figure out
how to use ANY niche.
But are we making conditions
conducive to life? Sure, some future epoch will no doubt see the rise of
complex plastic-eating bacterial communities, and some photosynthesizer will figure
out what to do with all our carbon. And of course, the rats and cockroaches and
pigeons and dogs and mosquitoes love us just the way we are. Aren’t we
just another inventive organism, blooming into a flowering radiation,
expanding unchecked into new habitats and diversifying into multi-forked branches
of exquisitely perfected niche-exploiters?
I believe this is
basically so. When humans encounter boundaries,
we diversify into different jobs, and stratify into different classes. Propagules
sail bravely off to find new worlds and new opportunities. But this time, its
different. Barring a juicy planetary discovery and a quick way to get there,
there’s nowhere left to go. Its time to figure out how to use this niche, Earth,
in a way that will sustain us. That’s our radical invention, right? We can figure out how
to use ANY niche. Which means figuring out a new strategy, a way to sustain a
diverse web of life that we can be a part of. A way to change our waste into
a resource for other organisms. A way to create
conditions conducive to life, and discover radically new ways of doing business. A way to blow the roof off this ecosystem, providing
all kinds of opportunities that weren’t there before.