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Lecture 8

Lecture 8

Biological Sciences
Course Code
Rudy Boonstra

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November 6, 2007
Future projections for vegetation.
National Parks and Reserves.
Now we will look at the future projections re: eco regions in the world.
Actual biological impacts of climate change we are observing right now. This portion
will cover the end of this one and the start of next one. I indicated the .pdf so hopefully
you got that.
What does the future hold for the world’s eco systems?
Tree and animal species are controlled by climate. If you get shifts in climate you will have
shifts in these eco systems. These are not unusual and we have seen these shifts continuously for
the last 1.8 million years and in fact longer than that. There is a problem for biological life now.
The first major problem is the speed at which change will occur in climate. It will be so fast it
will dwarf anything seen in the past.
Second major problem is that you no longer have a continuous land area to go across. It is
bisected and interrupted by human changes. Movement of plants is prevented from moving up
north whereas animals can at least walk to move.
Dispersal at the heart of movement might not be possible so we have to create corridors for
movement to occur.
Most plants won’t be able to maintain equilibrium with their current geographical ranges. If
plants and their communities they make up and try to keep their equilibrium they will only be
able to move approximately 10 km/year. They will have to move 5 x faster than the fastest
species we have seen in the past in rates of movement. Most species will have to be 50 x faster
as rates observed in the past.
The other thing to bear in mind is that the equilibrium where you get some sort of constancy
established won’t occur for about another 200 years with respect to what humans do to C02 and
other greenhouse gases.
On a slide last week, by in large communities are not organized like bodies or organized systems,
they are individuals so if we try to use the past to predict the future, can we see something
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similar in the past compared to the future we don’t think there is any analog that will allow us to
predict where the communities will be or what they will look like regarding adaptive
For many species of plants establishment of babies (seeds, dispersals) requires a disturbance of
the environment i.e. fire. Fire is a normal part of the environment because it prepares the ground
to provide a seed bed. So there has to be a natural disturbance. Another disturbance could be
pathogens and insects but normally species don’t get insect outbreaks on a regular basis. Ever
heard of spruce budworm? Algonquin has Balsam Fir which is very soft and people in the 50’s
looked at the budworm. It is a natural insect pathogen and the cycle is about 40 years and it
clears out the vegetation and then it grows again. I haven’t seen an outbreak lately because
Algonquin is about 60% logged.
Warmer climates are likely to have their most major impact on unmanaged eco systems
particularly the forests. The prediction is that by the time the atmosphere settles about 1/3 of the
world’s forests will have undergone major changes. The greatest changes will be at high
latitudes i.e. Canada, Europe, U.S.A., etc.
There is going to be a mismatch between the abilities of the plants and animals and the changing
environment. They won’t be in a locked step. Each animal and plant has a range of tolerance
and they have to be able to adapt but the environment they will find themselves in will be
mismatched in regards to their ‘niche or ‘characteristics’. So the animals and plants will be
vulnerable to all sorts of things i.e. spruce vulnerable to bark beetles. Some species will die and
stagnate and others will benefit particularly the invaders. In general the warmer temperatures
will be most stressful to species that are close to their warm tolerance limits and most beneficial
to those near their cold tolerance limits. We tend to focus on the terrestrial environment but the
aquatic environment will suffer as well. Basically you expect the shorter ice cover season on our
lakes, less ice cover means more time for biological production (plankton, fish, etc). The deep
waters of lakes have longer time to become anoxic (thermal stratification) and at lower levels in
the lake in summer they become oxygen depleted and that could last for longer. You expect fish
species composition to change. Cold water species will move south and warm water species will
increase. With global change it will be bass and those types of fish.
The other thing to remember is simultaneously the climate changes the aquatic eco systems and
terrestrial eco systems are being affected by other human insults like acid rain as well.
Temporarily at least we have a problem with UV radiation caused by ozone depletion.
Vegetation Changes
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Let’s look at the projections with respect to vegetation changes. This shows the global
vegetation in the year 1990. In Canada you see the Boreal forest and the open Boreal forest and
then the Tundra. You can see the Great Planes and the Grasslands. The tropical rain forests are
large. Now we will see what happens on the next slide. This is what it will be with the doubling
of CO2. Basically certain forest regions will increase markedly. You can see the forests in
Canada moving north and the Eastern Deciduous forests are moving to the west. Grasslands are
also moving and then we will be in trouble as that is where the ‘breadbasket is. They produce
the food we eat. Notice in Australia you have the dry inland areas and with global warming (in
this model) they will decline and you get the Grassland instead. Remember there is uncertainty.
If you look for potential for changes you will see the red squares and they indicate the areas that
would have changed as a function of doubling of C02 over 100 year span. I won’t ask you for
this number but the expectation of change in vegetation with this model is 34%. This chart is the
proportion of changes that will occur. Grey is not analyzed (Greenland) but the darker you get
represents a greater degree of change. Most changes will be in the northern hemisphere so you
can see they grayed from deep beige to brown. The changes are going to occur in northern
Europe and northern Russia. Some changes in the Amazon forest area as well. Australia also
changes especially as you get further away from the equator. If you look at the Canadian scene
you see the Boreal forest and eastern deciduous forests. You can see the Boreal forest increases
under this scenario (Potential Vegetation 2100). What aren’t uncertain are the Canadian forests
which will change very drastically.
You get the picture. It is rapid and major for Canada and much of the world at high latitudes.
Let’s take a look now as an example of change and the factors that will occur in causing that
change. Last week we looked at a wonderful American Beech tree that is about 100 years old.
What do we expect to happen with trees like that? What types of changes are likely to occur?
What will the future look like for these trees? I am giving the broad spectrum change and that is
hard to understand but if I talk about specific trees it is more understandable.
People have been making predictions for the last 20 to 30 years. The EPA (Environment
Protection Association of the U.S.) is a separate arm from the government, or at least it is
supposed to be. Once legislation is passed in the U.S. they have to do it unlike Canada. Our
Prime Minister can decide to do or not do things in Canada but it isn’t so in the U.S. The EPA
has been forward in thinking and in the 80’s they decided to protect the environment so they
wanted to predict where vegetation will go under the doubling of C02 so they can be proactive in
the future. They contacted a Paleo-ecologist (Margaret Davis, Katharine Zabinski) and they
modeled the Eastern deciduous trees i.e. Sugar Maple, American Beech, Yellow Birch, and
Eastern Hemlock. All these we know about. What they did is asked what is important about the
tolerance limits of the trees. They decided what was important was January temperature, July
temperature, and annual precipitation. If we can project where those conditions will be and
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