We were on a field trip to Otero Mesa, a huge and almost unpopulated area
between Carlsbad and El Paso. A crowd of visitors had gathered at an intersection
of dirt roads to listen to speakers from the New Mexico Wilderness Alliance
and the Chihuahuan Desert Conservation Alliance. The speakers were explaining
why this New Mexico grassland should be protected from oil and gas development.
One of the men listening had a child with him, a little boy sitting in front
of him stacking up rocks. The man asked one of the speakers, "What should
I tell my son about this place? Here he is, playing with rocks because he isn't
interested in what there is to see. What would be here if we had some rain?"
Good question. Otero Mesa is a grassland, immense, open to the sky, and for
now, desiccated. But, it is a desert grassland, and so drought is expected.
If it had received more moisture in the past few years, the black grama and
fluff grass might cover more of the dusty ground. But the other plants we saw
in abundance--yuccas, ephedra, creosote bush, snakeweed, cacti-have probably
not changed greatly as a result of the drought. For them dry is a way of life.
Appreciating this or any desert biome calls for close attention to subtleties,
such as the way the contours of the land change with the time of day or a Sclerocactus
hides under a shrub or prickly pear spines glitter when backlit.
Because the trip took place in the winter, the only green anywhere was in the
leaves of plants that remain green year round. Even the snakeweed, which is
green at its base in Carlsbad in February, was all dry and the color of ginger
from root crowns to tops. The only vibrant color in the vegetation was to be
found in the cacti. As the glare of midday deepened into the gold of afternoon,
their rose and purple hues stood out against the rocks when we hiked around
the foot of Alamo Mountain in search of petroglyphs. I particularly noticed
the Opuntia macrocentra, the black-spine or purple prickly pear, and one of
the rainbow cacti, probably Echinocereus pectinatus variety dasyacanthus (Ken
Heil's key).
The rainbows have always delighted me, even moved me to affection. Several
stems are often huddled together, covered with the banded spines that give the
plant its rainbow-like appearance. They have the look of small shaggy creatures
that just might have something to say, if I would stop for a while and listen.
They could tell me about the ways the rainbow cactus maintains itself in a place
where little rain has fallen in several years.
Their shape, for instance, the tapering, cylindric stems, provides a storage
facility for water. Inside is a mass of tissue of about the consistency of watermelon.
When it rains, the cactus fills with water it can then use carefully until the
next rain. The rainbow cactus has completely abandoned leaves as too expensive
in terms of water loss, so its stems have assumed their roles of photosynthesis
and the release and intake of water and gases. Such a fat, juicy stem would
dry out right away in the winds were it not for its cuticle, the waxy "hide"
of the cactus that prevents too much water loss.
The stem would also be an irresistible delicacy for thirsty desert critters,
were it not for the presence of spines. But the spines don't just deter munching.
They also provide a kind of slatted shade, rather like a pergola or arbor. The
spines grow from areoles, spots on the surface of the stems. Rainbow cacti provide
light-colored wool on the areoles at the tip of an actively growing stem to
serve as a protective reflector. The older areoles on the lower portion of the
stem do not have such wool any longer; it is less necessary, and the cactus
is thrifty.
In a place such as Otero Mesa, where human impact has been relatively slight,
climate and natural processes hold sway. Even in years of difficult drought,
the plants care for themselves, and if we look closely, we can both learn from
them and find beauty in their stark circumstances.