Introduction
What I'm speaking about today I have had a long
time to consider. And what I think about ecosystem management is in
essence "knowing your ecosystems and knowing your neighbors"--partly
borrowed from Steve Yaffee in the book that he prepared with students
of the School. My objective today is to speak about knowing and understanding
ecosystems. And, specifically, landscape ecosystems and their approach
in relation to the occurrence of the Kirtland's Warbler, which is a
case study. So, my presentation has two parts. The first is on landscape
ecosystems and what are they and how are they conceived. And the second
part is on the application of the landscape ecosystem approach in understanding
the occurrence of the Kirtland's Warbler, and assisting wildlife biologists
and managers in conserving and maintaining populations of the Warbler.
I have three points to make. First, there's no
shortage of methods for distinguishing, describing and mapping landscape
ecosystems. In Germany and Canada, it's been in progress for over 50
years. At Michigan, we've been directly engaged in this research for
over 20 years. We've tried to provide an ecosystem framework at regional
and local levels for the conservation, management and restoration of
segments of the earth. In part, due to the efforts of SNRE students,
Michigan's National Forests were the first to adopt an ecosystem approach
to a land survey, which spread to the eastern region of the U.S. Forest
Service. You'll find landscape ecosystem maps, called Ecological Land
Type Phases or ELTPs, in virtually every national forest of the eastern
and mid to western states, and applications of this in the southeastern
United States.
The second point is about the focus of management.
An understanding of landscape ecosystem units, their properties and
processes can be applied to a management focus for resources such as
water or timber or species such as the Kirtland's Warbler. The focus
can also be applied to entire landscape ecosystems. As we think about
what is being termed ecosystem management, it is important to identify
the focus of management. Whether it is on entire landscape ecosystems
or some part of a landscape ecosystem, such as a species, a commodity,
or a resource such as soil and water. Third, landscape ecosystems that
we distinguish and map, especially at the broader scales, can also serve
as sources of insights about people who are integral parts of ecosystems
and about societal issues specific to those landscapes. So, the maps
that I show and illustrate aren't just for ecological interests.
The Landscape Ecosystem Concept
Now, for over 35 years, landscape ecologist Jay
Stanwell has been most articulate in providing ecological and ethical
insights about landscape ecosystems and, as food for thought, I have
distributed a handout that includes a selection of his writings about
landscape ecosystems. I'd like to continue by examining three illustrations
of slides of landscape ecosystems. The discipline of landscape ecology
has brought a sustainability to the traditional concept of ecosystem
as a functional unit. Landscape ecology came to us from Europe and we
visualize this as a new way of sensing the world. It's a study of land
systems, and the relationships to one another for each is set in the
environment of its surrounding neighbors. Thus, practically, we see
landscape ecology as a science of landscapes understood concretely and
correctly as spatial and volumetric ecosystems in their regional context.
And so, in our work, we conceive ecosystems, the ecosphere and its landscape,
as ecosystems large and small nesting within one another in a hierarchy
of spatial sizes. So, the hierarchy of spatial sizes is very important
in the landscape ecosystem concept.
What are landscape ecosystems? These are structured,
volumetric units of the exosphere, and occur at multiple spatial scales.
A single ecosystem is a topographic unit, an air layer over the earth
layer with organisms sandwiched at the solar energized surface. These
are extended aerially over part of the earth's surface for a given time.
Tangelly, who coined the word, identified ecosystems as the basic units
of nature on the face of the earth. Here is such a volumetric unit [slide].
As you see on the upper left, this landscape is a continuum and we carve
out of this continuum these volumetric units. So, on the right you see
the layered structure, the macroclimate, the topoclimate, the biota
of the land form, the soils, the groundwater and the bedrock. Now, these
are layered units--the climate is layered, the soils are layered, and
bedrock as well. So, we have a layered volumetric unit. Notice it's
inseparable. So, what we try to study is something that's inseparable
as units.
Furthermore, because sight is a main human function,
we only see and therefore we only often perceive only about one-third
of ecosystems because the atmosphere is invisible and we don't recognize
the layers of it. The soil is under our feet and we rarely look under
the ground and, furthermore, the processes which characterize ecosystems
are out of sight/out of mind. So we're only seeing about the biota and
the land form a third, perhaps, of landscape ecosystems. They occur
in different units and so we can identify here in different landscape
areas three segments, three volumetric and layered segments, of the
ecosphere. This is the idea of the volumetric units. Here, we can identify
two ecosystems and we can study these on a horizontal basis. The ecosystem
on the left upslope, it has a different structure, a different land
form, climate and soil. And the downslope are lower slope ecosystems.
So, we can study these horizontally, side by side, or in space. Secondly,
we can study them vertically or study the processes and function of
the ecosystems. So, these are functional units. The ecosystem on the
lower slope has a different function in terms of carbon balance and
biomass accumulation, nutrient cycling, water cycling than the upper
slope ecosystem. So, we're interested in ecosystems because of these
functional processes to learn how ecosystems work. And this is a key
process for identifying and distinguishing ecosystems.
Here is a spatial example of how they occur in
the field [slide]. This is in northern Michigan and you see all of these
different kinds, different shapes, sizes, patterns of ecosystems related
to the lake, related to swamps, with many different kinds of patterns.
And here, the small swamps repeating again and again and again over
the landscape. So, once we learn these and map these and identify their
processes, we can extrapolate and use such maps in the management of
these units and their biota.
Ecosystem Classification
I first learned about ecosystems in Bodenvertenbarek
in southwestern Germany 40 years ago when I studied there, and discovered
that they were mapping and using these units in management. They developed
for the first time, perhaps, the heirarchical structure of identifying
for this whole landscape regional ecosystems for the Vine Valley, the
Black Forest, the Swabish Alp of Limestone, and here near the Swiss
Ura. These regional landscapes, landscape ecosystems, were subdivided
into districts units, a second heirarchical division, and then each
of these units could be subdivided again into a third level of hierarchy,
which could then be subdivided in local ecosystem units in each of these
regions. This approach was developed by a Jurist after the second World
War who was interested in humans and their relation to the landscape.
He wrote a book called Volatile Mench, that is "the forest in humans,"
and he was interested in human settlement and how they had changed the
landscape of southwestern Germany. And so, this whole research at a
research station--a team approach--was developed to understand how humans
had changed the landscape and how they could restore it to more natural
processes and functioning. What you see here was not done simply to
grow more Norway Spruce, but was for restoration of many of these whole
landscapes.
There are three examples. This is an example
of a landscape ecosystem map from the Black Forest. It is quite a different
picture from that in the Swabish Alp which is limestone based. So the
foresters who have charge of this, map whole units like this, and their
individual parts. Here's one on a river valley which is in a different
region, a different climate, has different public issues related to
the drainage and the canals along the river. In North America, we have
examples of ecosystem mapping. In 1976, Bob Bailey of the Forest Service
published his ecoregions. And here is an ecoregional map of ecosystems
at the broadest scale. You see these large, black lines differentiate
domains. That's large ecosystems and then they are divided into divisions
here. Then into provinces so you get to accepting these names for landscape
ecosystems at a regional level.
Well, we found this broad approach okay as far
as it went. But in Michigan there were only three units here for the
whole state. So, in the late 70s and early 80s, we set about to determine
the regional landscapes of the state of Michigan combining climate [the
work of Shirley Denton] using 30 years of records from 125 stations
with 225 variables over 7,200 townships. We integrated and developed
this climatic map of the state with lines put along physiographic boundaries.
Then we related this to the physiographic classification that Denny
Albert did over several years and integrated climatic classification
and the physiography and soil relationships to the integrated classification
in Michigan, using vegetation as well along the boundaries. So we have
regional ecosystem map for the state which could be used to identify
species and organism occurrences as well as managing whole units. This
is the Ann Arbor area. Here's the Detroit heat island. Although this
is an ecological map, it has many characteristics of human occupation
such as the agriculture in this subdistrict here. Such as the Traverse
City area of tourism and cherry growing.
Now going to the very local level in Northern
Michigan, we developed a protocol for mapping ecosystems using a physiographic
diagram. Physiographic diagrams show the lay of the land and the topography.
Each of these arrows distinguishes ecosystem type defined by the topography--the
soil, and the vegetation of overstory and understory, and ground cover
plants. And so, using this concept, using this physiographic diagram,
one can map ecosystem types at the local level. And this creates opportunities
to distinguish hot spots of diversity of ecosystems and, since bio-diversity
depends on ecosystems diversity, we can save and conserve many species
by identifying these hot spots of ecosystem diversity.
At the biological station we did another thing
in relationship to climatic change. The biostation is located in Region
II. The first hierarchical level is located in District 12 and Subdistrict
12.1. Those are three hierarchical levels and studying ecosystems within
that we can identify these major land forms: outwash plain, marine,
and ice contact. That's the first cut, that's the fourth hierarchical
level of ecosystems. We can then have a baseline for setting organism
change, ecosystem change, through time. Then we can subdivide these
major land forms into minor lands of rivers, sand dunes, more sand dunes,
carass fillings, outwashes of different kinds, gorges, and lake levels.
And so we subdivide again into ecosystems and finally, at the lowest
level, we can take an area like this land form, a gorge, and look at
its ecosystems and find and look at ecosystem diversity. See how diverse
this gorge area is compared to its associated outwash plain? There is
virtually no variation here but there are eight different kinds of ecosystems
in this one piece. So we find that wetlands and rivers are highly diverse
and important to conserve for ecological diversity and biodiversity.
So, to summarize this part, a key feature of the landscape ecosystem
approach used in Michigan, if not the entire United States, is first
of all, multi-scale. Secondly, especially at the University of Michigan,
we have emphasized multiple factors used simultaneously in the field
to determine these ecosystems. A cartographic approach is used so the
manager has an area that's tied to the ground. If managers move back
and forth, and don't stay in an area 30 years like they do in Germany,
then there is a testable hypothesis for these ecosystem types. And finally,
we use all the vegetation and especially the ground cover vegetation
in ecological species groups.
The Kirtland's Warbler
To apply this to the Kirtland's Warbler, we were
fortunate to have the encouragement of Dr. Sylvia Taylor, who suggested
that there had been a lot of work on the Warbler itself but little work
on the habitat of the Warbler. So, in 1986 we initiated work to study
the landscape ecology of the breeding grounds of the Kirtland's Warbler,
especially the area of Mack Lake in the northern lower peninsula. This
has expanded to work throughout several counties. The Warbler, discovered
about 1850, is now a rare and endangered species. As of 1960, they were
only 200 singing males, probably a population of about 400. And so people
were concerned about managing the Warbler. The bird nests on the ground
in Jack Pine forest along openings. So the openings of the Jack Pine
and the patchy character of Jack Pine after fires is very important.
It sings in the spring, arriving in May and so we obtained data from
census. People in the wildlife division and others have a census of
the singing Warblers so they can be mapped and we can identify where,
in the landscape, the Warblers are living.
The Warblers are pretty cool. They over winter
in the Bahamas. Not so bad. And then they fly to a very specific ecosystem
in Michigan. This is one of our regional ecosystems. This is the high
plains district and this is the Grayling subdistrict. You'll see this
was taken in late May and the purple and blue indicate frost conditions.
This area is extremely frost prone and characterized in seven counties
by the occurrence of the Kirtland's Warbler. Also growing here are species
like the Hills Thistle, Houghton's Golden Rod; these are rare or threatened
species. The Pale Agoscerus, the Allegheny Plum, and the Rough Ascu
are also plants threatened or rare here. Along this regional ecosystem
you can see how different it is in this May frost from these other regional
ecosystems adjacent to it.
So, we have studied not only intensively at Mack
Lake in this ecosystem, but at over five different sites the Warbler
has occupied over a period of 20 years or so. Our intensive studies
in the 80s and now in the 90s have been at the Mack Lake basin. Here's
Mack Lake and you can see this unique feature on the surficial geology
of Michigan from 20 meters away. It's a striking landscape surrounded
by physiographic systems of morain and ice contact terrain. Here's the
outwash terraces in glacial times--melt water drained the melting ice,
melting ice water moved into this pink channel up through the AuSable
River and on east to Lake Huron. The key thing about landscape ecosystems
and ecology is that we have to know our neighbors; to know the neighboring
ecosystems and to study the ecosystems of interest. The topographic
map shows the pattern of high terrain to the south. A distinctive break
occurs between the warm upper landscape here and the cold lower climate,
as cold air drains into this basin and it drains out. The cold air rains
out of these glacial channels where water once drained to melt water,
to the old AuSable Channel. So we have different levels here.
Here is old growth Jack Pine. On May 5, 1980
there was one of the largest fires in recent history. The Mack Lake
basin fire started as a prescribed burn to enhance the Warbler habitat,
because fire is a dominant ecosystem force perpetuating the Jack Pine
and the Warbler habitat. This fire got away and it burned 23,000 acres
in 13 1/2 hours running at a speed of 2 1/2 miles per hour, which was
one of the fastest moving fires in Michigan history. It burned 270,000
tons of fuel and liberated 3 trillion BTUs. The energy is that of 90
thunderstorms or 9 Hiroshima size atom bombs. This was an enormous fire
that burned over 23,000 acres and therefore provided habitat which the
Warbler then colonized. That fire burns erratically is the key to the
Warbler's success; that there are patches that are burned and patches
unburned. When the young pines regenerate, they regenerate in patches
forming openings that the Warblers prefers to nest near.
Also, I want to mention biological legacies of
the old forest. They burn hot. And where the woody fuel has burned extremely
hot, in this bare mineral soil around these places, excellent seed beds
for Jack Pine are created that develop taller than adjacent trees. So
these biological legacies are therefore very important in the success
of the Warbler. This is the area burned starting over on the upper left
where the fire got away. We have studied this area in detail and in
our approach we first worked from the top down. That is, we look at
the biggest part first. We would map this high elevation terrain, of
outwash terraces and ice contact terrain here. And, as you remember,
this is lower area--outwash plain and low level outwash. And the cold
air drains from the upper high to the low and out the channel. So we
have two basic land forms--the upper elevation and the lower land form.
We can study the Warbler occurrence in relation to these land forms
and also to the local ecosystem types that occur in these land forms.
We also learn through our landscape work that the soil is better nearer
the active development of the melting ice. So in this south part nearer
to the glacier we have better soil; we have large clay bands, we have
fine sand. Whereas down in the lower part it is more rinsed of clay
and we have poorer soil. So the combination of better soil conditions
and warmer temperatures has led to taller Jack Pines and more favorable
habitat for colonization of the Warbler. Thus, the Warbler's colonize
the high elevation areas first.
So the pattern has been that colonization is
related to the geology, and the physiography, and the soil, and the
plants; altogether a movement from the high elevation to the low elevation.
This is a pattern we find in other places in Michigan. So, the work
for managers is to identify land form ecosystems of outwash of ice contact
terrain, high level outwash, low level outwash, lower level land forms
related to moisture, water table, and then the lowest level land forms
related to the channel. So we are tracking the Warbler colonization
and occupancy in these land forms. Here's the channel area and you see
it's very short. This is 7-year old Jack Pine, 40 centimeters tall.
Just a mile away on the high level terrain, where there is better soil
and warmer conditions, the Jack Pines are over 2 meters. So, in these
pines and the patchy areas here, the Warblers came first. But the pines
grow very fast in this high level terrain. Here you see over seven years.
They grow much faster than the lower areas so these openings are closed
in and the Warbler moves out and moves into more acceptable habitat
in the lower area. With the work of Glenn Palmer, we've tracked and
measured the Jack Pine growth in relation to these ecosystems and we
see that the lowest level channel, the low outwash plain, the higher
outwash plain, and our best banded soils create significantly different
growth rates in Jack Pine. So the Jack Pine is interrelated to the climate
and the soil and the physiography of these landscape ecosystems and
related to the bird as well.
Conclusions
Population development in 1986 showed a remarkable
rise in the population of Warblers. At one time this area alone accounted
for 60% of all the Warblers in Michigan and along with another one about
80%. So, here is a graph simply of time and years and the number of
singing male Warblers counted in the census for the high level terrain
and for the low level terrain. You can see the dramatic rise in the
low level as the pines developed in size there. On the basis of percent,
you see high level occupancy first and initially colonizing the area
and its rapid drop off as it became less suitable for Warblers, and
then the low elevation coming in after that. So, the combination of
high elevation and low elevation landscapes was very acceptable for
a long duration of the Warbler. The bottom line is the interconnectedness
of the Warbler, not only to the vegetation, but back to the geology
of Michigan. The physiography of the landscape affects the soil and
its temperature which, in turn, affects the Jack Pine's height, coverage,
density and pattern; which is then perceived by the Warbler as quality
habitat. So, this is the interconnectedness of the landscape ecosystems
related, in this case, to the Kirtland's Warbler.
Because fire is dangerous people are cautious
about it. We put it on the back burner so to speak. People are planting
large areas of Jack Pine and they are trying to make openings for the
Warbler to conserve the Warbler. Because we had fire areas, the Warbler
spread into plantations but whether we can continue to use plantations
to conserve the Warbler is not sure. We have provided, through the work
of Dan Kashian, a study of 50 different areas to determine what conditions
of the landscape we should plant. We had two field days this year with
about 40 participants each to show them landscapes of the Kirtland's
Warbler, not only at Mack Lake but throughout these counties. The guideline
we have through landscape ecology is 'where you want to have duration
of Warblers for 5-15 years.' We want poor sites of cold and dry. Through
this procedure we are helping the wildlife biologists identify areas
for plantations.
This is an example of an ecosystem approach applied
to an organism. We could also apply the ecosystem approach to a whole
landscape or whole ecosystems. What is ecosystem management for us?
It's a matter of requiring mapped ecosystems and multiple scales so
we know explicitly where we are working and how ecosystems work. And
further, we recognize that it's an ecosystem approach with people attending
to conservation and sustainability of ecosystems, instead of sharply
focusing on the productivity of individual resources which has been
our traditional mode of operation. Now notice that our work in landscape
ecology has been applied to an individual resource. That is the Kirtland's
Warbler. We could equally apply this to whole landscapes and whole regional
ecosystems. In the words of Stan Rowe, it's important today to change
our understanding of the world; to focus on ecosystems rather than individual
species and organisms that are parts of them. Organisms are extremely
important and notable parts of ecosystems and they come alive when we
study them on an ecosystem basis. That's the message about landscape
ecosystems.
Please Note: If using
material from this presentation, please cite appropriately.
We suggest the following format:
Barnes, Burton. Landscape Ecosystems and the
Occurrence of Kirtland's Warbler in Northern Lower Michigan. 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.
