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Not Too Late for American Biodiversity?
Erin A. Tripp and James C. Lendemer
T
wo centuries ago, William Bartram, one of America’s earliest
natural historians, wrote while travel­
ing through northern Florida, “It may
be proper to observe that I had now
passed the utmost frontier of the white
settlements” (1791, p. 20). His geo­
graphic position had barely exceeded
the confines of the present day East
Coast megalopolis. However, he went
on to describe a wild and serene land­
scape of “endless” contiguous and
varied natural habitats: vast longleaf
pine savannas, extensive coastal and
inland wetlands, and majestic peaks of
unbroken forests extending outward
beyond their foothills in all directions.
A decade later, at the behest of Thomas
Jefferson, Lewis and Clark embarked on
an ambitious expedition to survey the
expansive, newly acquired Louisiana
Purchase west of the Mississippi River
and areas beyond.
Both expeditions encountered a
bountiful land of seemingly limitless
resources and yielded discoveries of
biological diversity unfathomable to
modern science (the majority of the
biota encountered was unknown to
science). At that time, collecting biolog­
ical specimens was considered among
the noblest and most-­progressive aca­
demic pursuits. Those who under­
took these pursuits—taxonomists,
­including botanists, ornithologists,
and so ­on—were highly regarded in
the public eye. Their efforts yielded
some of the most interesting scientific
discoveries of that period.
Much has changed in the interven­
ing two centuries: The majority of the
public is accustomed to a very differ­
ent physical and cultural environment.
We experience a radically fragmented
natural landscape and are increasingly
disassociated from ­biological diver­
sity and its value. We have become
desensitized to the current extinction
218 BioScience • March 2012 / Vol. 62 No. 3
crisis and are collectively blinded to the
­significance of the natural areas that
remain. Locally, we perceive dimin­
ished worth of our regional landscape
and lessened potential for taxonomic
discovery. But is this true? Our recent
studies of lichen diversity in some of
the very areas traversed by Bartram
indicate that the opposite is true. We
conclude that the need for biologi­
cal inventory and protection of natu­
ral resources in the United States has
never been higher.
Between 2007 and 2011, we con­
ducted a preliminary inventory of
lichens in Great Smoky Mountains
National Park (the Smokies), an expan­
sive 812-square-mile preserve situ­
ated in the southern Appalachian
Mountains. This region encompasses
the largest stands of primary forests
remaining in eastern North America
(ENA) and is surrounded by vast tracts
of forests, ranging from primeval to
secondary. Together, these forests
constitute the greatest wilderness in
ENA—most of it actively managed as
national forests for its natural resources
(extraction, conservation, and public
enjoyment). The Smokies, our study
area, constitute less than one quarter
of one percent (0.02%) of the total
land area of the United States. We
have demonstrated that, remarkably,
the park is home to 15% of all known
North American lichens and is prob­
ably home to more than a third of all
ENA lichens (Lendemer et al. 2012).
Over the course of only five short field
trips, we increased the park checklist
by 60% and recorded more than two
dozen species and two genera previ­
ously unknown to science, with many
more remaining in boxes yet to be
described. The species-accumulation
curve for the park’s lichens continues
to ascend, as yet with no sign of lev­
eling off. A nontrivial proportion of
these species are apparently endemic
to the southern mountains. What are
the implications?
Not only have we documented an
intact and unexpectedly hyperdiverse
lichen ecosystem (the most licheno­
logically diverse national park in
North America), but this biota exists
less than a day’s drive from the White
House. Along this drive, one would tra­
verse a 500-mile agricultural, ­forest, and
suburban mosaic before encountering
the core, contiguous woodlands that
constitute the southern Appalachians,
including headwaters and tributaries
of major ENA watersheds.
This region serves a more impor­
tant ecological function than has
perhaps yet been fully recognized.
Just as we safeguard our future food
resources through polar seed banks,
the ­southern Appalachians serve as
the major ­dispersal reservoir for ENA
lichens and almost certainly for many
other evolutionary lineages. Not only
does long-term natural integrity of this
region assure the persistence of cur­
rent lichen biodiversity, but it arguably
represents the most significant source
from which future lichen biotas will
derive in this half of the continent.
More than three centuries of
anthropogenic change have detrimen­
tally affected the lichen biota of ENA.
Historically widespread species with
continuous distributions have become
severely fragmented. Similarly, those
species that were always rare or that
have narrow ecological niches or
restricted geographical distributions
have become even rarer and, in many
cases, are highly endangered. All of
these changes indicate that the lichen
biota of ENA is experiencing regenera­
tion failure, with lessening viability of
species to disperse and ­persist during
environmental change. But we believe
that it is not too late.
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