FIELD NOTES
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“The
more you
learn, the less you know.”
Published
Spring of 2008 in “Our Town”
Not
the best
school motto, but nonetheless, a truism. Actually, I find it inspiring.
After
all, it is the search for buried treasure that motivates researchers.
But humankind
has accumulated so much information that it’s sometimes hard to believe
there
is anything left to learn, which can be discouraging to an aspiring
explorer. As
a contribution to the documentation of our ignorance, and with the hope
of
stoking the embers of curiosity, I offer this brief essay on what we
don't know
about the animals with whom we share our landscape, except that what we
don't
know is surely much more than I can even imagine.
Let's
start
small. Really small. Microscopic creatures are easy not to know. Their
effects--rotting
wood, steaming compost piles--may be visible, but they themselves are
not.
Someone once estimated that the biomass of underground microscopic
organisms
may exceed that of organisms who roam the surface. Some of these, for
example,
fungi, periodically become visible, and some are only debatably
animals, but
the point is that there is a vast, underground world teeming away out
of view.
There are surely thousands, if not hundreds of thousands or even
millions of species
of microscopic organisms going about their daily lives under our feet.
They are
the largely unsung support crew for many of our plants--mineralizing
rock,
capturing nutrients from the air, and forming strange collaborations
that help
plants collect solubles from the soil.
Explorers
of the
underground realm are only beginning to discover it. Methods are now
available
that allow us to begin to catalog residents, but in most cases, we
haven't the
foggiest idea what these creatures are doing. It's as if somebody
handed you a
very incomplete list naming the animals in a forest, but you had no
idea which
ones were birds, frogs, mammals or ants and were nearly clueless about
who ate
whom or what. Under the ground we are only beginning to realize that
the
equivalent of rabbits aren’t fleas, and turtles aren’t rocks.
We
have come up
against this corner of the unknown in our work with farmers, here in
Claverack
and elsewhere in the county. They want to know if they’re using their
grasslands
sustainably. Or, more precisely, how much can they graze or hay a field
without
slowly robbing it of its nutrients and degrading the soil into near
sterility?
This
is not as
straightforward a question as it might seem. Our grasslands are not
passive
pools of nutrients depleted by harvests and restored by fertilizer.
They hum
with life, and that life helps plants grab nutrients out of the air and
scrap
them from the rocks. So, the question is really this: At what rate are
these
on-the-scene workers gathering nutrients relative to the rates at which
we are
removing them with our harvests? And more important, is there anything
we can do
to make their job easier? The answer is, we hardly know. The beam of
our
flashlight has fallen on only scattered corners of the underworld arena.
But
surely we
know more up here in the visible world, no? Well, yes, we know a bit
more about
say, bees than we do about microbes. We know that there are probably
something
like 400 to 450 species of native bees in our state, although there are
surely
still species left to discover. But what are all those bees doing?
Where do
they live? What, if any, pollen and nectar do they seek? How do their
lives
interact with ours? Given the recent concern over the fate of the Honey
Bee
(which was introduced to our continent by European colonists), it is
amazing to
realize how little is known about the other bees who, though they
rarely make
honey, can be important pollinators. For most species of bees, we have
no idea
whether their populations are nose diving, rocketing upwards, or are
relatively
stable.
Our
own work, in
collaboration with Martin Holdrege, is a small contribution to the
knowledge of
bee pollination of crops on local farms, including at least one in
Claverack.
When added to information gathered from the few other wild bee
researchers in
the Northeast, it might provide us with a better understanding of what
all
those bees are doing. If we can learn which bees are most important for
the
pollination of which plants, then perhaps we can begin to better manage
our
land for the well-being of those species. Right now, our understanding
of bees
and their ecology is probably equivalent to what Audobon knew about
birds. We
know some things, but there is an immensity still to learn.
Our
unknowing
extends to all insects. We are not even sure, for example, if some of
our most
showy butterflies, such as the Tiger Swallowtail and Pearl Crescent,
are single
species, or two or more look-alikes. One of our most gorgeous
butterflies, the
aptly named Regal Fritillary, has completely disappeared from the
region over
the past 50 years, but there are only wild guesses as to why that
happened. And
then there are the ants (probably 60 to 70 species in New York),
spiders
(around 700 species), beetles and moths (thousands). The numbers of
these
organisms is daunting, their ecological role likely huge, and the
number of
people studying them, pitiful.
But
the frontier
of our knowledge is hardly over the horizon even when it comes to such
seemingly well known species as frogs, birds, and mammals. Take the
Wood Frogs
and Spotted Salamanders who show up at many local pools in the spring.
Their
early-April orgies are conspicuous, and so where and when they breed
and lay
their eggs is fairly well known to us. But what do they do the rest of
the
year? Where do they forage in the summer? Where do they sleep in the
winter? We
have some rather precise physiological knowledge of how Wood Frogs
freeze (and
survive to unfreeze) in the laboratory, but we have very limited
knowledge of
where they pass the winter in the wild. Likewise, Spotted Salamanders
are part
of a group called mole salamanders, and yet we have only glimpses of
whose
holes they use, how deep they travel, and what, if anything, they do
while
underground.
Birds
are
perhaps the best known group of animals, simply because so many people
watch
them. The dedication, expertise, and prevalence of birders is legion
and inspiring.
And yet, and yet. Bobolinks are raucous summer residents of our
late-mown hay
fields. At the right place and time, they are hard to overlook as males
jockey
for females, and later in the year the fledglings stumble into the air.
But
where do they go during the off season? Southwards surely; Bolivia and
Argentina probably. A friend recently went in search of their winter
quarters.
She found a few birds, but I don’t think she came close to convincing
herself
that she could state with certainty where all Bobolinks overwinter.
And
what about
shrews? Short-tailed Shrews are the size of a mouse; with their tiny
eyes and
grey velvet coat, they are often mistaken for moles. They are also, to
add an
exotic twist, one of the world's only poisonous mammals. Not to worry;
their
saliva has little effect on us, but what is it about the lives of these
animals
that makes poisonous saliva so useful? Cat owners may see the
occasional
short-tailed shrew among the offerings on their doorsteps, but the
nether-reaches of the shrew world are the Sorex,
or long-tailed shrews (Sorex is
their
scientific name, apt for a small creature with a pointy nose.) They are
some of
the tiniest mammals in the world. Our smallest local species weighs
about as
much as a penny, its heartbeat can exceed a thousand beats per minute,
and when
active, it must eat more than three times its weight every day. There
is even a
Water Shrew. Slightly larger, it lives along and feeds in small creeks.
Diving
into cold water seems slightly suicidial for an animal already living
on the
metabolic edge of feasibility, Does this species occur in Claverack, or
anywhere in Columbia County? We don’t know. Few, if any of us, have
ever seen
one. Sorex could wink out of local
existence and nobody would notice, at least not directly.
This
possibility
of indirect effects brings us to the final aspect of the unknown-- the
complexities of the ecological web. How do species interact?
A
recent feature
on NPR revealed the role that wolves play in controlling stream erosion
at
Yellowstone. Apparently, the wolves scare elk into spending less time
browsing
streamside willows, which allows the willows to grow up. The willows,
in turn,
stabilize stream banks. While we currently have no breeding population
of
wolves or elk in the county (although we probably did once), we do have
coyotes
and white-tailed deer. The role of deer in the alteration of forest
composition
is well documented, but how do increased coyote populations affect the
patterning
of ‘forest management’ by deer? What aspects of the “natural”
appearance of our
landscape are actually reflections of this complex interaction which
certainly
includes us as actors? That one animal eats another is obvious, but
when one
species subtly changes the behavior of another, few of us have the time
or the
inclination or the powers of observation to notice.
And
how about
the interactions of ants and butterflies? One family of butterfly, the
Blues of
Nabokov’s study (represented locally by Azures and Hairstreaks) have
developed
interesting relationships with ants. Somewhat like aphids, the
caterpillars of
certain species are tended by ants. The ants glean a sweet liquid from
the
caterpillar and in turn, appear to protect the caterpillar from
predators. But
the plot thickens. In some cases, the ants appear to be so taken by the
caterpillars (thanks to some tricky caterpillar chemistry) that they
even carry
the caterpillars in and out of their nests, thereby protecting the
caterpillars
when they are not feeding. In Europe, it appears that some Blues have
adopted a
Trojan Horse tactic that takes advantage of the ants’ hospitality. When
brought
into an ant nest, the caterpillars of these species begin to eat the
ant
larvae. Does this happen amongst any of our local species? I asked one
of the
most knowledgeable Lepidopterists I know. His answer: No idea.
And
finally,
rabbits. Most of us see rabbits regularly, and yet the only county
mammal
currently under consideration for Endangered Species status is a
rabbit—the New
England Cottontail. “On the hoof,” the New England Cottontail is nearly
indistinguishable from the Eastern Cottontail. Fifty years ago, New
England
Cottontails abounded in the region; A hundred years ago, Eastern
Cottontails
were nearly unknown east of the Hudson River. As a result of expansion
into
changing habitats, fueled by human introduction, the Eastern Cottontail
has
spread throughout the area, and the New England Cottontail has
virtually
evaporated. Today, all (or at least almost all) the rabbits around us
are
Eastern Cottontails. Do the two species compete? Is our hand in
changing land
cover playing a major role? Might New England Cottontails still live in
Claverack? We can only guess. (Based on surveys that others have
conducted
regionally, the answer to the last question is probably ‘no’, but I’d
gladly
inspect any rabbit skulls found in the woods, as the two species can be
differentiated
by skull traits.)
Not
all of these
unknowns (a very partial list) may seem important from a human
perspective, but
how can we know what’s important, when we don’t even know what’s
happening?
Furthermore, the needs of our own species can’t be our only criteria of
importance. Yet we can’t evaluate what might be important to other
species,
when we barely grasp their natural history. This is hard to believe in
a time
when so much information is available at the click of a
mouse. But the Age of Complacency
seems to have
followed the Age of Discovery, at least in the field of natural
history. Books
about animals are bursting with details of the known, but if I ever get
around
to publishing my “Idiot's Guide to the Unknown,” it will be filled with
blank
pages.
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