Introduction
The issues of elk management, wolf recovery,
and fire management policy are issues that epitomize ecosystem management
in Yellowstone, and throughout my talk I will be making reference to
these three issues. Dean Dan Mazmanian sent me a list of seven questions,
and so I have organized my presentation around those seven questions
and I am going to try to address each of them. The first one that he
asked me to address was my conception of ecosystem management.
Conception of Ecosystem Management
I have some fairly specific ideas related to
ecosystem management for Yellowstone National Park as well as for the
Greater Yellowstone Ecosystem. The ideas are related to what I think
parks are all about. I believe that the objective is to allow ecological
processes to operate unimpeded by human influence as much as possible
and, to serve as ecological baseline controls which are necessary to
evaluate the consequences of human activities outside of our national
parks. As scientists in particular, we need these controls to evaluate
the consequences of human development and other activities outside of
parks.
But, in particular, I am an advocate for an ecological
process management paradigm for our national parks. This is similar
to what many of you have heard of as natural regulation, but perhaps
without some of the semantic baggage. Natural is a word that is debated
amongst philosophers, in particular, whether or not humans belong in
natural systems. The word regulation has very specific implications
for me as a population ecologist because it implies density dependence.
It requires a regulating mechanism of some sort and there's much more
to the processes that operate in natural systems beyond density dependence
that I believe that are embraced by this concept of natural regulation.
So, I am going to use the terminology "ecological process management,"
which entails allowing natural ecological processes to run their course
unimpeded by human influence as much as possible. This includes such
ecological processes as nutrient cycling, succession, fire, flood, competition,
predator prey interactions, wolves and ungulates.
Now, there are a number of models for ecosystem
management; connecting models that have been proposed in the context
of Yellowstone National Park. First, Adam Smith's paradigm has been
suggested for Yellowstone. The Pacific Research Institute for Public
Policy has proposed that the parks should be transferred to private
ownership and that hunting and mining be permitted in the park. I'm
going to dismiss this particular proposal rather cavalierly because
I believe that it's constrained by public interest. But the second vignette
is one that's very frequently referred to and it refers to Aldo Starker
Leopold's suggestion in 1963, that national parks ought to be vignettes
of pre-European humans. They ought to provide snapshots of what America
was like, say, in 1850 in the case of Yellowstone National Park. That
we ought to be trying to reconstruct what the park looked like at the
time that Europeans first saw these places. Unfortunately, I don't think
that this is a very realistic paradigm because ecological systems are
terribly dynamic and to reconstruct exactly what a particular piece
of landscape looked like, perpetually, is probably even impossible in
some systems.
So, these systems are always changing and certainly
Starker was very aware of this and the idea of a vignette is, in some
instances actually misused, because one has to take a much broader picture
of the ideas that Leopold captured in the 1963 report. I would just
like to comment briefly about Hunter's Triad approach. This refers to
Mac Hunter, University of Maine, who wrote a little monograph suggesting
that there may be three objectives that we ought to be trying to meet
simultaneously in ecosystem management. One would be fiber and food
production. We ought to be focusing on some areas that are very good
for producing needs of humans. That we ought to have other portions
of the landscape that are set aside for strict protection, preservation
areas. And, that we ought to have other areas, the third category of
areas, where we have sort of experimental ecosystem management type
landscapes where we creatively try maintain ecological processes and
biodiversity while, at the same time, allowing human use of those areas
such as extractive forestry and hunting and other activities. Hunter's
Triad approach, I think, is a broader vision and, in the context of
the Greater Yellowstone Ecosystem, I believe that there are portions
of Hunter's Triad approach that I think are worthy of attention.
Why is Ecosystem Management Needed?
So why is ecosystem management needed in Yellowstone?
I have already touched on the issue of parks as ecological baselines.
I believe that this is one of the most important functions that our
national parks can provide. Most of the landscapes in the United States
have been altered by humans and we need places where we can see what
happens when we don't alter those areas. In the Greater Yellowstone
Ecosystem we have a diversity, however, of management jurisdictions.
In particular, the National Park Service manages Yellowstone and Grand
Teton National Parks, and the John D. Rockefeller Parkway between the
two parks. The Forest Service is largely responsible for managing most
of the rest of the Greater Yellowstone Ecosystem surrounding Yellowstone
and Grand Teton Parks. There are also private lands and some state and
BLM land ownerships in scattered pieces. Ecosystem management is also
needed to coordinate resource management over this large area with a
diversity of jurisdictions. Many ecological processes, for example elk,
wolves, and fire, do not respect jurisdictional boundaries.
What do Practitioners Need to Know?
What do practitioners need to know to succeed
with this approach? This was the toughest question. I had to really
think about what I was going to say on this one. First and foremost
in my opinion, practitioners need to be good ecologists. One cannot
expect rational perspectives and decisions without the fundamental basis
in ecology, even though many of the resource management decisions will
be made in a political forum. The breadth and depth of science necessary
to really understand ecology is enormous. Ecosystems are the most complex
entities. The most complex systems in the universe governed, not only
by all of the physical laws of chemistry and physics, but also embracing
biology and ecological interactions. A good ecosystem manager must have
a very broad background in science. Ecological process management does
not imply hands off management. Rather, informed intervention. One of
the examples that all of you have heard about is wolf recovery.
Grizzly bear management, since 1983, has required
very aggressive management by the National Parks Service and the U.S.
Forest Service and the Fish and Wildlife Service. I have listed some
other examples here. I will talk a little bit more about grizzly bear
management. During the period from 1970 until 1983, grizzly bear populations
declined in the Greater Yellowstone Ecosystem due, in large part, to
very heavy mortality. Approximately 40% of that mortality was related
to hunting in one way or another. In 1983, the inter-agency grizzly
bear committee was formed and very assertive programs to try to reduce
human bear conflicts were implemented. Since 1983, the population of
grizzly bears has increased by 5.5% per year. The last two years are
not on this graph but they are actually higher than any of the points
that are this map today. Which, of course, is leading to more and more
conflicts with people outside the park.
Adaptive management should be the approach for
dealing with such management interventions. This methods injects the
scientific method into the process of resource management. There are
four or five primary steps here. First, is the explicit formulation
of the hypothesis or a model that outlines how we understand the system
at the outset. This step is often times overlooked or trivialized in
presentation of adaptive management. But I think it's probably one of
the most important so we can really be clear on what we do learn. The
next step is an active management intervention of some sort followed
by monitoring. Then an evaluation of the consequences. Then a revision
of the hypothesis or a change in the model and then changing the management
and trying again.
Defining Successful Ecosystem Management
Ecosystem management is a never-ending process
and we will never complete it. We will never seem to get it quite right
because doing it right means that we are always learning, changing,
and improving our management. What constitutes success? With wolf recovery
in the Greater Yellowstone, all the pieces are there now. Minimal human
disruption of the ecology of the park might be an interesting target
but it's always there. For example, the increases of carbon dioxide
in the atmosphere is something that we cannot eliminate from the system.
And there are always going to be perpetual challenges associated with
boundaries, exotics, global change, and migratory species such as elk
and birds. The monitoring, I believe, is essential to evaluate how well
we are doing with ecosystem management but it's not well done now and
often not supported by management or by government funding. In fact,
if there's one major failure in the Greater Yellowstone Ecosystem management
today, it is the weakness of the monitoring schemes that are in place
and our inability to get support for monitoring in the Greater Yellowstone.
Human and Social Aspects
What are the human and social aspects of the
Yellowstone case? This is the arch at the entrance of Yellowstone Park
[slide]. The motto above the arch reads, "For the benefit and enjoyment
of the people," which is explicitly charged in the Organic Act of 1916.
Indeed, human and social values drive most park management. Fact is,
that ecosystem management cannot work without public support. Many of
the current issues in Yellowstone National Park are issues because of
human and social pressures and conflicts. Bison management in Yellowstone
National Park has become very controversial in the recent past, due
in part to conflict with livestock industry outside the park. It's concerned
about the spread of tuberculosis. Another human social pressure shaping
resource management in Yellowstone relates to the winter use in the
park by snowmobiles and these snow coaches. The roads through Yellowstone
National Park are used very heavily by snowmobiles during winter, and
it's thought to enhance the movement of bison in the park. Mary Marr
argues that this actually increased the carrying capacity of the park
for bison, making access to alternative winter ranges easier for the
bison.
Another very contentious issue in Greater Yellowstone
is whether or not there are too many elk and bison in the park. This
is another issue where human values and social interactions have complicated
management. Over several years I've tried to compile the reasons that
people believe that it's necessary to cull elk in particular, but also
bison, from Yellowstone National Park. The first of these is that ungulates
damage vegetation. I find that word damage inappropriate for an ecologist
in view of the fact that, of course, ungulates eat vegetation but whether
or not they damage it implies a value judgment that I find uncomfortable.
The best reason that culling has been supported for Yellowstone National
Park is that the government seems to have a double standard for livestock
ranchers. That livestock ranchers find it very disconcerting that we
can have native ungulates having the same magnitude of effect on the
vegetation inside the park but, if that were to happen outside the park,
it would be totally unacceptable.
The next issue is that some people believe that
native Americans killed ungulates within the park prior to European
appearance in the area and that we ought to somehow be targeting what
the native Americans were doing in the area. The next issue relates
to biodiversity because beaver on the northern range, in particular
in Yellowstone National Park, are much less common than they were, say,
during the '20s. Also, white tailed deer habitat has been diminished.
Some people believe that we should be culling ungulates in the park
to enhance habitat for both beaver and deer and other associated species
in Yellowstone National Park, trying to maximize biodiversity. Some
people have argued that erosions are elevated in Yellowstone National
Park, especially in riparian areas. And then finally, several people
have argued that culling in the park is needed to counter anti-hunting
interests. That is, that it's necessary, somehow to cull in the park
and that hunting interests find this necessary to promote their interest
in sport hunting.
Now, whereas all of these issues I think may
have a basis and there's some logic behind the arguments, I think that
they are all misplaced in the context of ecological process management
for Greater Yellowstone and I'll address each of these. First off, the
issue about whether ungulates ought to be affecting the vegetation.
Some people believe that you shouldn't see the influence of ungulates
on the vegetation. But there is no question that ungulates influence
vegetation. They eat vegetation. Is Yellowstone overgrazed? Well, plant-herbivore
dynamics are a natural ecological process. Of course they eat plants.
It's one of the ecological processes that we need to be protecting in
Yellowstone National Park. Graham Cauly emphasized how ungulate dynamics
are a consequence of trophic level interactions. Of course they influence
the vegetation. There's also a dynamic interaction between herbivores
and predators and these are fundamental ecological processes. There
are a number of exclosures in the Greater Yellowstone ecosystem and
many of these show very dramatically the effect that ungulates have
on the vegetation. On the left, you can see the exclosure where the
vegetation is about 6 to 8 feet tall. To the right, outside the exclosure,
we have the same density of willow plants but they seldom get more than
about 18 inches before they are nipped back by ungulates. Actually,
I think the proper interpretation of these exclosures is how drastically
we have influenced the vegetation by excluding or reducing herbivory.
A number of early explorers coming across North
America commented on the large effect that ungulates have had on the
vegetation. There are a number of places where bison, for example, just
clobbered the vegetation and there was severe eroding of stream banks.
We know that ungulates influence the vegetation and they have done so
forever. Trying to eliminate these influences just doesn't make sense
in the context of managing to maintain ecological processes. Jack Ward
Thomas, has pointed out to me that when he served as Chief of the Forest
Service, it was a very uncomfortable issue for him to justify restrictions
to ranchers when people would look at Yellowstone National Park and
see that the consequences of ungulates on the range was very pronounced.
I say we need Yellowstone to be able to evaluate the difference between
livestock and wildlife. Kay thinks that native Americans reduced ungulates
population and he thinks they reduced ungulate populations to a large
degree. I think that this is fascinating and I've always been fascinated
by the history of natural resource exploitation by humans, but I think
that it's irrelevant. We know that humans can decrease ungulate numbers.
But we have all of Western North America on which we can evaluate the
consequence of manipulating ungulate numbers. Only in the parks can
we evaluate the consequences of minimizing human influence.
Beaver populations have, almost certainly, decreased
on the northern range and probably throughout the park. We don't know,
however, what the dynamics of beaver populations in the park will be
or whether their numbers are just fluctuating through time. Whether
their numbers will be higher at some point in time in the future. We
do know that there is a dynamic interaction between beavers and vegetation
but also between the ungulates and the vegetation. White tail deer,
in Yellowstone National Park, have always been rare. With the fundamental
issue here related to biodiversity is one with which I disagree. I disagree
that maximizing biodiversity should always be the target of ecosystem
management. Especially on local spatial scales. We need broad scale
management for biodiversity and the Kirtland's Warbler, I think provides
an excellent example of how a large scale management scheme is what's
necessary for biodiversity preservation. There is no species of plant
or animal that is threatened by ungulate management in the greater Yellowstone
ecosystem.
The erosion evidence is equivocal in the Greater
Yellowstone Ecosystem. Certainly, if there's any influence of ungulates
on erosion, it's trivial by comparison to the major erosional processes
that occur in places such as the Grand Canyon and on Mount Everest.
A number of places where there is major erosion that happens after a
rainfall, for example, and the extent to which ungulates may be aggravating
that, is minuscule by comparison and, there is debate amongst a few
soil scientists on whether or not there's any measurable consequence
to erosion. But, certainly I think, the evidence is very clear that
it's a very minor contributor to erosion in the park.
This issue of whether hunting is necessary is
one that I find discomforting because I enjoy hunting. And there are
a number of people, I think, that are actively involved in this issue
of ecosystem management for Yellowstone that are also hunters. But,
I think a lot of us recognize that hunting has an appropriate place
and it needs to be justified with sound ecological arguments. But the
arguments that have been advocated here are not sound. There's no way,
to my mind, that we can claim that hunting is absolutely necessary to
regulate or control ungulate numbers. Charles Kaye says that if natural
regulation is correct, ungulates do not have to be hunted or preyed
upon to prevent them from damaging their environments. That word damaging
comes in again. This would remove a major ecological rationale for sport
hunting and wolf reintroduction. Charlie actually wrote an article lambasting
the federal government for their wolf recovery programs so we know where
he stands on that issue. And Charlie clearly has, as a major motivator
behind his advocacy for hunting in the park, a need of hunting, which
I don't think he can justify.
To summarize some of these recent points, we
do not know appropriate stocking levels. Therefore, culling or killing
within the park would be arbitrary. I believe that in the current context
it's very important that we allow wolves to determine how many ungulates
there ought to be in Yellowstone National Park. Nearly everywhere in
America is under human control. Yellowstone and other parks ought to
be where we can let nature take priority and I believe that's a very
important point; that we need these baselines. More reasons to let it
be. Only by maintaining ecological baseline controls can we assess what
we do elsewhere. With wolves in place we should not interfere with an
opportunity to evaluate the consequences of wolf predation. The timing
couldn't be worse. Over the last year there's been a very aggressive
effort to try to reinstate hunting within Yellowstone National Park.
Killing of ungulates. Representative Hill from Montana in particular,
as well as Charles Kaye and Fred Wagner who have been advocating the
return of hunting to Yellowstone National Park. Grizzly bears are faring
very well, off of spring carcasses. So high ungulate numbers has certainly
benefited the grizzly bear recovery program. And, of course, there is
an enormous desire on the part of visitors to the park to see ungulates.
They appreciate high ungulate numbers so there is also a public visitor
benefit.
Spatial and Temporal Issues
What are the spatial and temporal issues for
management of the Yellowstone ecosystem? My immediate response to this
question is that ecosystems are dynamic and if we learned anything in
ecology in the last 20 years it is that a trophic level of interactions
by themselves can maintain perpetual fluctuations in ecosystem dynamics.
We know that ecosystems aren't constant and that they are changing all
the time and the dynamics, per se, may be fundamental in the way in
which ecosystems work. I have been intrigued to see how popular the
observation of predation incidents in Yellowstone National Park has
been subsequent to wolf recovery. Wild fire created an enormous public
outcry in 1988. Last winter several thousand elk died and a few hundred
bison, as well, died on Yellowstone's northern range. Just to put it
into context however, in the state of Montana, 80,000 cows, cattle died
during the tough winter. But we never heard any comments to the effect
that ranchers were being irresponsible for loss of their ungulates during
that winter. It was deemed something that they couldn't help I guess.
Fires of 1988 reset the clock on succession in about 25% of Yellowstone's
landscapes. The only solution, I suspect, to these issues relates to
public education and the park has done a magnificent job, I believe,
on fire ecology for several years. And it may, in fact, still be there
at Grant Village. They have had a public education program on fire ecology
that I believe has gone a long way to improving public understanding.
They have also attempted to explain to the public that we expect to
see over winter kill during tough winters. But still, we see strong
reaction when these events actually happen temporally from time to time.
One approach suggested for ecosystem management
in the national parks is to set goals for management. Society expects
goods and services from ecosystems. A number of park service biologists
have argued that we should be setting goals for national parks. We ought
to be setting goals for the number of ungulates that we have in Yellowstone,
and the types of vegetation and the acreage of various vegetation types
that we have in Yellowstone. One of the most vociferous advocates for
this approach is a fellow by the name of Bonickson, who advocates setting
quantitative and measurable standards of ecosystem structure and function
as a part of reference area goals. We can't do this. There's no way.
Even wildlife managers admit that they don't have a fraction of the
knowledge that they need to be able to manage ecosystems well.
Ecological process management might be proposed
as a reasonable goal for national parks. And if somehow one felt obligated
to slip into the Franklin paradigm of accommodating goods and services,
I'd offer these definitions as a possible way to accommodate that. Aspen,
in Yellowstone National Park, has been the source of considerable discussion.
Dynamics, per se, are essential for Aspen recruitment. When elk numbers
are down and moisture regime is high after heavy rains and high soil
moisture, only under those circumstances can we have Aspen recruitment.
During the fires of 1988 everyone presumed that we would have substantial
Aspen recruitment because the extent of the fires was sufficient that
the Aspen should be able to escape herbivory. That just didn't happen.
The Aspen has been well trimmed since the fires of 1988 because ungulate
numbers are high and it's been relatively dry. Aspen maintenance in
Yellowstone National Park requires dynamics and allowing ungulate populations
to fluctuate, which includes major crashes perhaps after severe winters.
Maybe, as a consequence of wolf recovery, allowing those dynamics to
happen is probably necessary for the maintenance of this ecosystem component.
What can Yellowstone teach us about ecosystem
management?
I'm going to answer this question in the context
of the Greater Yellowstone Ecosystem, which is a vast area. And as I
mentioned, there are a number of different jurisdictions governing the
management of these lands. I've tried to develop the position that ecosystem
management involves maintaining the integrity of ecological processes.
And, elk, wolves, and fire epitomize ecosystem management. But this
is not a preservation paradigm which in some contexts is viewed as a
sacrifice for nature. A few years ago, at a Greater Yellowstone Coalition
meeting in Yellowstone National Park, I asked Tom Lovejoy why we ought
to be focusing on preservation in Yellowstone National Park? He told
me that preservation was important to provide an example to developing
countries. That if we couldn't do it how could we expect them to do
it. I think actually it's the wrong example. I think that, in fact,
the paradigm ought to be closer to this one: the sustainable development
paradigm of elk, wolves, fire, and people in the Greater Yellowstone
Ecosystem.
We need places like Yellowstone National Park
as core areas but we can manage the Greater Yellowstone Ecosystem under
the ecological process paradigm. Including people requires consideration
for various sorts of resource use outside the national parks. Much can
occur without significantly disrupting ecological processes. Prince
Phillip visited Yellowstone several years ago and commented that for
those interested in conservation, the very word Yellowstone is like
a battle cry. This is where it all started. Yellowstone was the first
wilderness set aside for a national park and it remains an inspiration
and the confirmation that dreams could be made to come true.
Please Note: If using
material from this presentation, please cite appropriately.
We suggest the following format:
Boyce, Mark. The Greater Yellowstone Ecosystem.
Presentation given at Symposium "Ecosystem Management: For a world we
can live in." September 25, 1997. University of Michigan, School of
Natural Resources and Environment. Ann Arbor, MI.
