Subject: ** What Resource Inventories Don't Tell Us **
Next week about 200 people will gather in Phoenix, AZ. for the
"Integrated Ecological and Resource Inventories Workshop."  In "What
Resource Inventories Don't Tell Us About Biological Diversity, and
What We Really Need to Know," Winifred Kessler highlights concerns
that should be on the table (whether or not they will be) at the
workshop. Kessler focuses on biological diversity, ecosystem health
and integrity. Kessler suggests that we need to shift our focus from
"stocks" and "flows" of resources to "states" of ecosystems--that are
practical indicators of ecosystem health.  5 pages.  Dave.
PS.  This should be considered "required reading" for workshop goers.



      What Resource Inventories Don't Tell Us About Biological Diversity,
                        and What We Really Need to Know

                            by Winifred B. Kessler*


       What should be said about biological diversity in a conference focusing
on  natural resource inventories?  One possibility is a discussion of what
forest and other inventories can tell us about biological diversity.  That was
my initial thought, but one quickly discarded.  That's because the resource
inventories we have tell us very little about biological diversity. 
Furthermore, the more important questions are what inventories do not tell us
about biological diversity, and what we really need to know.

       Let's being by defining what is meant by biological diversity.  Among the
most widely used definitions are these:  biological diversity is the variety of
life and its processes (Keystone Center, 1991); and, biological diversity refers
to the variety and variability among living organisms and the ecological
complexes in which they occur (U.S. Congress Office of Technology Assessment,
1987).  Mere words and phrases, however, are inadequate to portray the
incredible complexity that is biological diversity.  In popular usage, we tend
to think of it as the variety of organisms in an area.  But it includes so much
more than the organisms themselves.  It includes the complex pathways that link
organisms one to another and to the environment, their genetic composition, and
the processes that sustain the whole as dynamic, self-adjusting systems.

       We often speak about biological diversity as if it were just another
attribute of the forests, rangelands, and other ecosystems we manage.  We search
for simple counts or indices to measure biological diversity.  After all, if
biological diversity is an important resource issue, shouldn't we include it in
our inventories?  Unfortunately, the problem is not that simple, for several
reasons.  We'll talk about those reasons shortly.  But first, I think we need
to address an even more basic question.   Why has biological diversity become
such a hot issue today?  

Why All the Concern?

       The most obvious answer is this:  because species are disappearing at
unprecedented rates.  But for many people, even this answer is insufficient. 
"So what," they argue, "we know from the geologic record that mass extinctions
have occurred before, for example the disappearance of dinosaurs some 65 million
years ago."  The fact of extinction is not in question, however; the real issue
is the rate of extinctions today.  Bear in mind that a few inches in the
geological record represent many tens of thousands of years.  Thus what we
interpret in the rocks as "rapid" rates actually represent numbers of
extinctions per tens of thousands of years.  In contrast, rates today are
estimated in the range of thousands or tens of thousands of extinctions per year
(Myers, 1979). 

       Another important distinction is the nature  of extinctions today.  While
the geological record does reveal the disappearance of many species, in fact
most of these went "extinct" by evolving into a new form, better suited to
changing environments of the time.  The genetic lines remained intact in these
cases.  Today, in contrast, the extinction of a species means that a genetic
line has been truncated, terminating any further evolution of that line.  

       What are the consequences of these trends, and implications for natural

resources management?  An obvious consequence is the immediate loss of many
values associated with a diverse biota.  Because these include social,
ecological, and economic values, the arguments for conserving biological
diversity are many and run from the esoteric to the purely pragmatic (Oldfield,

       Perhaps we in forestry and other natural resources tend more toward a
pragmatic viewpoint, consistent with our utilitarian traditions.  Conserving
biological diversity just makes sense, because the surest way to sustain yields
of natural resource products and services is to maintain the integrity and
productivity of the ecological systems that produce them.  We also have learned
that some "worthless" species turn out to pharmaceutical goldmines, as in the
case of the Pacific yew (Beattie, 1992).  Hence the wisdom of keeping a full
diversity of flora and fauna, lest we let some species of potential value go

       Consider also the weighty ethical questions concerning our obligation to
future generations.  We can only speculate about the possible long-term
consequences that current losses of biological diversity may have on ecological
systems of the future, including humans.  The extinction of a species is the
truncation of a unique genetic lineage that is here today because it survived
and adapted to change in the past--a process made possible by the variety of
genetic material within that lineage.  Biological diversity is a buffer against
environmental change and uncertain events.  Given the evidence of a rapidly
changing global environment, we may be losing genetic resources at a time when
diversity is needed the most.  The loss of a few charismatic species, where most
popular attention is focused, pales in significance compared to the real threat,
which is endangerment of the very process of evolution along a path that
includes humans.

Biological Diversity Defies Measurement

       Whether conserving biological diversity is regarded as an ethical
responsibility, a ecological necessity, or just another legal requirement, we
need systems to measure biological diversity and detect whether change is
occurring.  In other words, biological diversity must be addressed by inventory
and monitoring procedures that are both practical and effective in telling us
what we really need to know.  That sounds simple enough, but it is a challenge
that eludes ecologists and natural resource managers alike.  Let's look at the
reasons for the difficulty.

       Biological diversity is so much more than a head count of species.  It's
useful to think of biological diversity not as an attribute, but rather as the
very fabric of ecological systems.  The species that make up this fabric are
interwoven in complex ways that give integrity, strength, and beauty to the
whole.  This "tapestry" is something quite different from a pile of threads that
have been randomly joined together.  It is a complex, resilient, and
self-regulating entity that equals far more than the sum of its component parts.

       The tapestry analogy helps illustrate why biological diversity defies
characterization by a straightforward inventory process.  The important thing
about a tapestry is not the total number of threads, nor even that you have many
different colors of threads.  What matters is that each thread of a given color
and type has a particular role and place within the tapestry, such that all form
a functional, strong, and harmonious whole.  

       Similarly, the story of an ecosystem's health and integrity is not told
so much by the total number of species observed as by what those species are. 
Do they belong there, as part of the functioning whole?  Or does their presence
indicate, or even contribute to, a deterioration of the whole?  In the case of
"weedy" organisms, both plant and animal, we find that invasive behavior usually
is a response to ecosystem deterioration--a process of replacing native species
that no longer can thrive.  

       This is why a species count or diversity index can give a totally
misleading picture about the health and integrity of the system.  In a species
count or simple index, for example, brown-headed cowbirds would count just as
much as pileated woodpeckers, and kudzu as much as big bluestem.  In reality
they are at opposite ends of the spectrum--one negative and one positive--in the
roles they serve in ecological communities.

       Moreover, a simple species count, and even the "diversity indices" that
factor in relative abundance and other attributes, cannot help with the really
important questions having to do with the integrity and health of the forest,
rangeland, wetland, and other ecosystems we manage.  In the fabric of an
ecosystem, how many stitches can be cut, and how many threads pulled, before the
fabric begins to weaken in its ability to resist stress?  How many more before
the fabric--or ecosystem--begins to unravel?  These are the real questions that
challenge us as ecologists, natural resource managers, and citizens of the

Inventory Shortfalls and Pitfalls

       So biological diversity, by its complex nature, defies measurement by
simple counts and indices.  How might we need to change our existing inventories
to evaluate biological diversity, and to make interpretations about the health
of forests and other ecosystems we manage?  Adding a few more inventory elements
is not the answer; rather, we must add a whole new dimension that has been
neglected in the past. 

       There are three ways to characterize the forests and other ecosystems
that we manage for their natural resource values:  states, stocks, and flows
(Brooks and Grant, 1992).  Of the three, states have largely been neglected in
our resource inventories.  That is because our focus has been on the yield of
products and services from the forest, rather than on the condition of the
forest itself. 

       These biases are seen in our resource inventories, which contain abundant
information on the stocks of resources available per unit area (for example
timber volume, deer densities, miles of hiking trails, pounds of forage).  Our
inventories also contain information on resource flows, or the periodic yields
expected from the system (for example annual fiber production, pounds of
anadromous fish, water discharge, or animal-unit-months of grazing).  But only
limited information is available on the state of the forest or other system, and
what attributes are measured tend to be biased toward the products of interest
(for example stand age and composition, tree vigor, deer browsing).  Only
recently have we started to include other key attributes concerning the states
or conditions of the system; for example woody debris, floral and faunal
composition, snags, canopy structure, and patterns of habitat fragmentation.  

       The USDA Forest Service, came to recognize the significance of these
shortfalls in a very painful fashion.  Following passage of the National Forest
Management Act in 1976, the Forest Service engaged in what likely is the largest
and most complex land-use planning effort ever attempted.  The public was
involved in the process, and what resulted were comprehensive plans providing
the best management direction ever for the 156 national forests managed by the
Forest Service for multiple uses.

       It has been very difficult to implement many of these plans, however,
because they are frequently the object of appeals and lawsuits from public
interests.  The issues vary, but a common theme prevails in many of the
complaints.  The plans, and the public involvement process used in developing
them, related primarily to the kinds and amounts of things to be yielded from
the forest:  board-feet of timber, animal-unit-months of grazing, recreation
user-days, and so on.  This situation has its roots in our resource inventories. 
The bias toward resource stocks and flows over resource states carried forward
into our analyses and planning documents.

       For many people, projections of what can be removed from the forest are
no more important, or even less important, than what will be left on the land. 
People are very concerned about the condition of the forest that will result
from the planned activities.  Prominent among their concerns are such states and
conditions as water quality, scenic beauty, and biological diversity.  For many
years, ecological scientists have been recommending that more attention be given
to the conditions of the systems we manage.  And now that message is coming loud
and clear from the greater public as well.

Ecosystem Vital Signs: Our Greatest Inventory Challenge

       I'll close by making a case for what, in my opinion, is our greatest need
in the inventory and monitoring arena.  Today forestry is going through a change
in philosophy, policy, and practice that involves a significant expansion from
the traditional task of sustaining yields.  The new approach, usually referred
to as "ecosystem management," has a goal to sustain diverse, healthy, and

productive ecosystems in the long term (Society of American Foresters, 1993). 
This requires careful attention to the ecological "fabric" of the systems,
meaning biological diversity and the vital processes that ensure ecosystem
relisience to short-term stresses and adaptation to change in the long term.

       Managing for healthy ecosystems sounds like a good idea, but how do we
know a healthy ecosystem when we see one?  We have urgent need to develop
practical and meaningful indicators of ecosystem health, comparable to the
"vital signs" used in human health.  The health professions have developed a
standard set of measures to quickly assess the state of health of individuals;
blood pressure, cholesterol count, and blood chemistry are well-known examples. 
These indicators can be used on humans of any race, age, gender, or lifestyle. 
Knowing the ranges that these values should take on for a given population, a
health professional can evaluate the condition of individuals and monitor change
through time and in response to treatments.  

       Can you imagine trying to practice health management without these vital
signs?  How, then, can we expect to practice ecosystem health management without
an appropriate set of vital signs for the systems we manage?  What kind of
indicators can tell us whether all the components and processes--the biological
diversity--of the systems appear to be intact and functioning?

       In the important endeavors of resource inventory and monitoring, this is
the greatest challenge facing scientists and practitioners today: development
of a conceptual framework, indicators, and methods to evaluate the condition and
health of the systems we management.  We need ecosystem vital signs, and we need
them urgently.

Literature Cited

Beattie, J. E.  1992.  Human benefits from protecting biological diversity:
       the use of Pacific yew in cancer treatment.  Forest Policy Center,
       American Forests, Washington DC.

Brooks, D. J. and G. E. Grant.  1992.  New approaches to forest management,
       parts 1 and 2.  Journal of Forestry 90(1):25-28 and 90(2):21-24.

Keystone Center.  1991.  Biological diversity on federal lands.  Report of a
       Keystone policy dialogue.  The Keystone Center, Keystone, CO.

Myers, N.  1979.  The Sinking Ark.  Pergamon Press, New York. 

Oldfield, M.  1989.  The value of conserving genetic resources.  Sinauer 
       Associates, Sunderland MA.

Society of American Foresters.  1993.  Sustaining long-term forest health and 
       productivity.  Report of a task force of the Society of American
       Foresters.  Society of American Foresters, Bethesda, MD.  (In press)

U.S. Congress Office of Technology Assessment.  1987.  Technologies to maintain
       biological diversity.  U.S. Government Printing Office, Washington, DC.

*      Winifred Kessler is Principal Ecologist for the WO Range Management
       Staff: W.Kessler:W01A. This a draft of work to be published in
       Proceedings of Penn's Woods - "Change in Challenge," a conference held
       at Penn State University, April 1 - 2, 1993.