Introduction
I guess I should start with a couple of warnings.
One is every good discussion requires a little bit of antagonism. I've
got the job of representing a slightly different group of people, who
have been working with slightly different kinds of ecosystems than most
of the speakers have been talking about up until now. I'll tell you
that for me and for many aquatic ecologists, there are some frictional
issues. And I would like to talk a little bit today about frictional
issues with respect to ecosystem management. I am also a person that
doesn't like lots of suspense and, in fact, I don't like suspense very
much at all. It makes me nervous and so I decided to put the conclusion
right in the title so you know where I am coming from. You know my bias.
Like everyone else here I am, in fact, very much an enthusiast of ecosystem
management. So the friction is not about "is ecosystem management something
that's valuable at all," but there are some things us aquatic ecologists
and terrestrial ecologists need to talk about in terms of what we mean
by ecosystem management.
Watershed versus Ecosystem Management
This smoke, hopefully there's a little intellectual
fire behind it, that will clarify for all of us what it is we think
we are about when we talk about ecosystem management, has to do with
this word 'watershed.' Over the last four or five years, as I've watched
the term ecosystem management develop in the conservation literature
and the people upstairs in our school [all the aquatics people are in
the basement and all the foresters are on the second floor] talk more
and more and begin to organize their program around ecosystem management,
I've had this nagging feeling that this is a wonderful thing. I'm very
much in favor of this. But what exactly is it? They are talking about
watershed management aren't they? As I talk to my aquatic colleagues
I think I've found a similar kind of response. Yes, ecosystem management
sounds like a wonderful thing. What exactly is it and is it the same
thing as watershed? Is that what they mean? Do they mean manage watersheds?
Is watershed management really the aquatic ecologist's equivalent of
ecosystem management as we have been talking about it here today?
That confusion or that friction, I think, actually
has a basis in some important principles for thinking about ecosystem
management. It's true that Tansley was a trusted ecologist. We will
grant everyone that. But if you talk to an aquatic ecologist, we will
be pretty much convinced that the idea of ecosystem and ecosystem ecology
really is a pretty aquatic topic. I mean it was looking at the lake
as a microorganism, and it was Lendeman with trophic dynamics, and it
was really the sort of Herculean international efforts in the 50s and
the 60s that unraveled the meaning and causes behind eutrophication
that led to much of what exists as functional ecosystem ecology today.
To aquatic ecologists, whether they study rivers, lakes, or wetlands--and
I'll focus my comments today largely on rivers--it has been clear that
the management of these systems must be based on larger functional ecosystem
units. And we have called this and taught, really, for 20-30 years now,
watershed management. So maybe you will understand that when people
say ecosystem management our first reaction is "oh well, you mean watershed
management." We think about the landscape in that way. Is ecosystem
management really watershed management or is there something more to
the concept? That's really the topic that I'd like to try to address
today.
I'd like to start with the observation that whether
you are talking about ecosystem management in a terrestrial system or
watershed management in an aquatic system, there's a common sort of
larger flow in our management history and in our management science
that they are both a part of. That is the idea that whatever we do in
managing the landscape in terms of policy or action, it needs to be
consistent with the reality of the system that is out there. And after
all a good definition for science is we try to shape our mental pictures,
our hypothesis, our models in a way that reflects what the reality really
is. So the discomforture that ecologists feel when we start talking
about landscape ecology comes down to differences in the way we perceive
the reality that we're talking about in terms of ecosystems, and often
in the words and the boundaries that we're talking about when we use
the word 'ecosystem.' And it's a simple case example that Burt just
went through. Burt was showing you maps of regional ecosystems of Michigan,
and there was a very large major boundary there cutting across the middle
part of the state. River managers look at that and say, "But, gee, there
are four major river systems that come across that ecosystem--that major
eco-region boundary." The correct unit for ecosystems, they would say,
aquatic ecosystems, something like a river, must be different. We must
be talking about something different. So, that's the issue I'd like
to address. When we say ecosystem management, what are we really talking
about in terms of units on the ground? If the common tradition is to
shape your science so that it fits the real ecological reality that's
out there, then to address the question of what is ecosystem management
in the context of rivers requires looking very carefully at what a river
ecosystem is, and then trying to build some kind of a statement about
what that must mean in terms of ecosystem management. And so what I'd
like to do pretty rapidly is just tick off for you some of the major
characteristics of river ecosystems and contrast them a bit with the
kinds of terrestrial systems that we've been talking about.
Riverine Ecosystems
First of all, river ecosystems are landscape
scale systems. In other words, they're very large systems, and although
we've talked lots about landscapes in the sessions today, river systems
are, in terms of a truly integrated unit, amongst the largest kinds
of systems we have. This is a local system, a local stream, Milk Creek,
just right outside of town. It's a piece of the Huron River basin and
it's about 15 square miles. But a river manager would recognize it as
an ecosystem, a part of the Huron River system, which is a part of the
Lake Erie basin, which is a part of the St. Lawrence River system, and
the St. Lawrence system is on the scale of hundreds of thousands of
square miles. And so, the first important feature, if we're going to
talk about ecosystem management of rivers is to recognize that we're
talking about very large systems on the scale of the landscape. Secondly,
rivers are somewhat different than the kind of systems we've talked
about so far in their internal structure. We say in class they are hydrologic,
geomorphic, biologic systems. That is to say, they have a very real
physical component in a way that's different than a lot of the terrestrial
systems when you're talking about managing. For example, if you take
the biology out of a river system, you still have a river system. If
you take the biology out of a forest, you don't exactly have a forest
anymore. There's something different about the way we use the terms
'ecosystem' in these two contexts.
It is a fundamental nature of river systems that
they are arranged spatially, and this gets us to this idea of watershed
in a hierarchy nested fashion. Every river system can be viewed as consisting
of a series of catchment areas on the landscape that contribute water
and sediment and nutrients to that system and link the river system,
which is a discrete ecosystem visually, to the overall landscape it
sits in. The idea of the watershed as the length between ecosystems
in the landscape is, as I say, fundamental to the way we've been talking
about managing aquatic ecosystems for some time. And there's really
no better demonstration of the essential power of this way of thinking
about aquatic ecosystems than a quick 3-dimensional view, if you will,
of the river systems of Michigan. In this case, we're going to look
at three slides in succession here. The first is very much like the
slide that Burt showed a while back. This is a picture of the surficial
geology of the state. This is sort of the under layer of the State of
Michigan. The yellow is glacial, thick deposits of glacial drift of
outwash. Sandy areas of, as Burt said, well rinsed soils carried by
glaciers and deposited in a thick layer. The green is recessional marine
feature and till plain, and the pink is old lake bottom. So, that's
the bottom layer and the structural foundation of the large scale picture
of the State of Michigan. This is the topography. Wherever we had the
sand, the yellow, notice now that we have high, thick deposits of outwash.
Where we had lake bottom it's kind of dark, and relatively low elevation
topography in the marine.
The next slide is a picture of the river systems
in Michigan. It's just a map. But notice that the river systems--if
you let your eyes blur a little--notice this is the same map. This is
a map of the landscape of Michigan. The underlying surficial geology,
the topography, the river nets upon them, is the same map. Rivers are,
because of the way they integrate the landscape and their catchments,
they essentially are the landscape. Or, that's a good metaphor for them
at any rate. But they are tightly, tightly connected to the landscape.
So, the idea of watershed management and real physical units that an
aquatic ecologist would argue are the units around which one should
structure management is a powerful concept for thinking about these
systems. But it isn't the only way to think about these systems. It's
also true that a river is a network and the network has pieces and anyone
who's a canoeist or a fisherman or spends time on a river knows that
as you traverse a river net there are areas that are pretty much the
same and other areas that are very different. They share physically
important similarities in things like chemistry and the biology that's
there. This is a clear segment and you could walk the segment for 3
or 4 or 5 or 10 miles and it essentially will look like this and essentially
will have roughly the same chemistry and biological character. This
is another segment. It's in the same river. It's part of, in some sense,
the same ecosystem, but it is distinct. This is another segment. It
has a different fish fauna, a different chemistry, a different relative
energetic balance in terms of energies of the flow and its riparian
environment, etc. But it is part of the same overall watershed system.
And so, it is a characteristic of river systems
that they, in fact, have two distinctly different physical expressions.
They have what I'm going to call structural ecosystem expression--that
is, they have a channel unit that's distinctive--and linked to a functional
ecosystem, another spatial unit, that creates it. But notice in a river
system, they're not the same place. And this has been a key factor in
thinking about the problem in the management of these sorts of systems.
That is, this bottom segment in the diagram is a discrete piece of real
estate and the catchment that produces it is a discrete piece of real
estate but they're not the same piece of real estate. They're not even
at the same scale. A river segment that is ecologically homogeneous
and structurally homogeneous may be 15, 20, 30 miles long, but the catchment
that produces it may be 300 square miles in size. And so, there is a
very different way that the basic ecology of a river system lays on
the landscape than if we take as contrast the nested hierarchy of ecosystem
types that Burt talked about in terms of the Kirtland's Warbler. Rivers
are maybe the most extreme example of this, but we know that this is
fundamentally the same in lakes. That is, we manage lakes and we've
learned through the eutrophication crisis of the mid-part of the century
that a lake has a very nice boundary, but if you're going to manage
it that isn't the boundary you have to worry about. There is a functional
system boundary that is discrete and is real, but that is the unit one
manages.
And so, there's in aquatic systems of all types
this sort of dichotomy. There's two sides of a coin because of the physical
way, the physical reality of the structure of aquatic systems. There
is a local effect and there is a regional effect and we routinely have
built this into the way we think about aquatic ecosystems. Three very
quick examples. This is so obvious that most of us don't think about
it. But the last 10 or 15 years in river management we've spent a lot
of effort and time focusing on the distinction of managing for point
source effects and nonpoint source effects. Essentially point source
and nonpoint source effects are the difference between chemical controls
at this place in the river based on the catchment, and chemical controls
at this point in the river based on some discrete place on the channel.
The chemistry of any particular type of site depends upon not what's
at that site but on the landscape in the catchment. Data from a very
small catchment, less than 50 square miles of drainage in the Titabiwassi
River in the Saginaw Valley area, shows tremendous differences in alkalinities
between agricultural, lowland forest, and swamp catchments all inside
the same river system. This same principle is true at almost every level
of aquatic systems we look at, particularly in river systems. That is,
there is an off-site set of processes and properties that affect it,
they come from a real spatial unit, it has real boundaries, and there's
an on-site set of properties. And, together, they produce some physical
expression that we recognize on the landscape.
Another example: In stream ecology when we talk
with engineers about discharge, the most fundamental parameter in describing
any place in the river is how much water goes through it. We use routinely
two essential equations to describe the same thing. If the discharge
is the water going through that cross-section we can describe Manning's
equation, which says essentially that the water going through that cross-section
depends upon the slope and the frictional resistance. It's true. It's
always true. You can fit it anywhere. It describes the discharge through
that section. But on the right is another equation. It says the discharge
through that section is the result of the water balance for the entire
catchment. It's a difference between precipitation, evapotransporation,
and change in storage. These equations are the two sides of the river
ecosystem--the large unit and the local unit--and they're both always
true. And in fisheries habitat we see the same kind of principle. In
fact, we teach students to watch for and to think about whether the
particular problems at a site in a river are due to the catchment unit
[big spatial unit] or whether they're due to the local unit. And in
this case the slide is illustrating the difference between a site that
has reasonable fish habitat potential [it has good undercut banks, it
has good woody debris structure, it has good flow during the summer]
and one that has none of these things. It has poor flow, sediment has
impounded the channel, the channel is too big, the water is barely snaking
through, and the woody debris that's there has removed the actual flowing
water, so it's of no use to the fish. The difference between these two
kinds of sites--real sites that Dave Allen's group has been working
on for a number of years in the River Raisin--has to do with manipulations
in the catchments. They're not due to the spatial unit we're looking
at. They're due to the spatial unit that functionally controls this
local expression.
Ecosystem Management for Rivers
So, what is ecosystem management for rivers?
Is it just watershed management? I think if the river managers are going
to take something away from the discussion of ecosystem management and
we look at it carefully and we use the principle that ecosystem management
is shaping your management to the reality, then the answer is it is
something more than watershed management. It is watershed management
but it's also channel management, and it's also the conscious integration
of all the systematic forces that shape the nature and the piece of
nature that we're interested in, that both aquatic ecologists and terrestrial
ecologists in short-hand refer to as ecosystems.
What do we need to do this kind of work? How
do we become ecosystem managers if we're river managers? Number one,
I think we need to understand the structural and functional realities
of the systems we have. And in fact rivers are structurally and functionally
built differently than lakes, and lakes are built differently than forests,
and forests are built differently than wetlands or whatever other kind
of ecosystem you want. We have to understand the underlying reality
that we want to manage. Number two, whatever that reality is--whether
it's forest or aquatic systems--we need to be able to specify the appropriate
spatial unit. I think one very clear, common thread in ecosystem management
and watershed management is the belief, at least on the part of most
scientists, that these are real units, these are real spatially delimited
units, and it matters what we do where. Identifying them, and that's
one reason mapping is such a powerful tool, is a necessary first step
to doing ecosystem management in rivers or anywhere else. To be true
to the idea that ecosystem management in rivers is the combination of
watershed management and dealing with local issues and expressions we
need to apply integrative tools. And we talk a lot in SNRE about integration
between different disciplines, but now this is integrating between different
views of the same reality--between the regional reality and the local
reality, the watershed and the channel segment. We need likewise to
apply integrative tools to decide what it is we want to do with what
we have. And then finally we need to act. In all these levels, though,
we need to act in a way that's consistent with the actual physical reality
of the systems we're discussing.
Tools for Implementation
Quick review of some tools that have turned out
to be important and that I think are moving us forward towards an ecosystem
approach to managing rivers. One very fundamental tool, the School of
Natural Resources and Environment, has been a leader in this university.
Frankly, this university has been a little behind but is now rapidly
catching up in terms of the application of Geographic Information Systems.
One of the great attractions of this technology is it allows us to deal
with the large scale picture and think about it in terms of its effect
on specific ecosystem components. GIS technologies allow us to think
about and to integrate information at both these scales--the watershed
scale and the local expression. Ecosystem unit mapping and classification
happens to be an area that, in the last two or three years, everybody
is jumping on the band wagon very rapidly in aquatic systems. We're
beginning to realize that mapping the units that are really the expressions
of watersheds is a powerful management tool, particularly a tool for
dealing with specific political and social issues in regard to river
management.
Finally, modeling from the landscape which uses
information at the landscape level to make predictions about the character
of local expressions of ecosystem and local ecosystem structure is,
with the advent of GIS, becoming a very important tool in landscape
management of rivers. Just like we need integrating structures and science
to think about this problem, we also need appropriately scaled social
organizations that do this. This is true whether we call it ecosystem
management or watershed management. One of the things that's been going
on in the last decade that's extremely encouraging has been the development
of alternate big scale structures to think about river systems, which
are so large they normally traverse the organizational boundaries that
we align ourselves in politically. So, watershed councils, an idea that
had early expression in this state and has been particularly successful,
is now a concept.
A watershed council is an alliance of governments
along watershed boundaries to specifically think about managing large
aquatic units. It is now spreading to the East Coast and the West Coast
and more and more one hears of ecosystem management being carried out
for aquatic systems by things known as watershed councils. In Michigan,
maybe some of you aren't as aware of a secondary category [they're not
legally quite the same thing as a watershed council] but resource conservation
development councils have played a tremendous role in the restoration
and management of large pieces of rivers in a number of areas of the
state. One, I think it's called the Pines RC&D in Grayling, has been
a primary organizer of people and money for the restoration of the AuSable
River. The Rouge project is a unique alliance of government and private
concerns spending, with the help of the federal government, major effort
and millions of dollars in the restoration of the Rouge River.
Conclusion
When it comes to these systems and to river management,
our history has been to manage by default. Rivers, because they are
landscape systems, integrate the landscape. People, because there's
a lot of us and because of whatever it is in us that makes us what we
are, modify the landscape. And therefore, we do landscape management
on rivers whether we intend to or not. And that brings us back to the
conclusions of this talk--there's no choice in terms of river ecosystem
management because we are already doing it. The only question is will
we do it well or will we continue probably in the long run of history
not to do it so well. There is no choice and there is no retreat. No
retreat because since 1972 we've begun, in terms of river management
anyway, a path in which we've tried to address the unique problems of
managing these large systems. Today we are making headway, I think,
in terms of the science and we're making headway in terms of the social
organization to do this job. Really, at this point, all we can say is
let's keep on going. This is no time to hesitate and we should be looking
over our shoulders at the terrestrial ecologists and people talking
in more general terms about ecosystem management and we should be applauding
and we should be saying let's together learn how to manage the large
scale environment that we live in.
Please Note: If using
material from this presentation, please cite appropriately.
We suggest the following format:
Wiley, Michael. Ecosystem Management and Rivers:
No Choice and No Retreat. 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.
