Skip to main content

Full text of "Endangered habitat : wildlife in danger"

See other formats




Edited by Richard C. Passmore 


a WWdYuvI0d | 

magine yourself on aspaceship about to blast off for a distant 

planet. The spaceship would be carrying all the food you were 
going to use on the journey. It would carry all the water you 
would need, all the air that you would breathe and it would 
have to be heated so that you could survive the sub-zero 
temperatures of outer space. It would have to contain means 
of storing all the wastes that were produced enroute, and 
if the trip was to be a long one, the wastes would have to be 
recycled or used again, to help grow additional food. The 
spaceship, in short, would have to contain a complete system 
for supporting life. Needless to say, if anything went wrong, 
the lives of all the people on the spaceship would be in danger. 

Does this seem far fetched? Does it seem unlikely that you 
will ever take a space voyage? If, at first thought, your answer 
is yes, it would be wise to think about it again. For you are ona 
spaceship and we call it the planet earth. It contains all the air 
we need to breathe, all the water we will use for drinking 
and for many other purposes, and it is a complete life support 
system. Furthermore, if anything goes wrong with this system, 
the lives of all the passengers on Spaceship Earth will be in 

When we think of the planet earth as a system that supports 
life, we must realize that various kinds of life exist on earth. 
Each type of life has certain requirements for its own survival. 
Wherever these requirements may be found, we can say that 
there is a suitable environment for that type of life. 

As a people, we are one of many species inhabiting earth. It is 
our “habitat” — a “habitat” is a place where something lives. 
As Canadians, we inhabit Canada, but we cannot divorce 
ourselves from the rest of the world. If our habitat deteriorates, 
everyone suffers. In a narrower sense, some plants and animals 
are totally dependent on habitats threatened now with 
destructive changes, even with annihilation. We all share in the 
responsibility of doing something to correct this situation. 

After little more than a century, Canada has built a modern 
society based on abundance, freedom, and enterprise. Yet 
during the last decade, we have awakened to a deteriorating 
environment, shortages, pollution, and high cost resources. 
We thought “it couldn’t happen here”. 

The irony is that we are the second largest country on earth, 
a richly diverse land with supposedly inexhaustible resources 
to supply our small population. How could this paradox come 

Rec’ . mAUKS 2.4| 74 

Order Not Evee 
Ace. Naz CVSS 

The answer is that the environment has always been taken 
for granted as infinite, free, and forgiving. We now know that 
environments are more like bank accounts. No matter how 
large, there is only so much. Some environments are like 
savings accounts and bear interest. If we use only the 
productivity of renewable resources like interest, we can 
continue to do so forever. If we use more, some day the capital 
will have vanished. 

Other environments are like current accounts. Nonrenew- 
able resources bear no interest. What is used is gone, forever. 

When Europeans first came to Canada, it was aland rich with 
life. Forests stretched coast to coast. Huge herds of bison and 
caribou roamed open land. Lakes and streams were full of fish. 
The air was sometimes dark with birds. 

Now the passenger pigeon is gone along with the great auk, 
Labrador duck and sweet chestnut tree. Bison and muskoxen 
barely survived, caribou remain in jeopardy and are not 
likely ever again to darken the landscape with their numbers. 

The forests, once thought inexhaustable, are depleted. Some 
forest types persist only in farm woodlots or as parkland 
samples. It is authoritively stated that one third of all native 
plant species are now seriously depleted, rare or endangered. 

Oceans have been heavily exploited for about one century. 
As recently as a decade ago, their productivity was touted as 
the great hope of abundant food for mankind. Now, fish 
stocks are depleted, and some of the great sea mammals, 
whales, are threatened with extinction. We are consuming the 
bank balance itself instead of living on its sustainable 

New automobiles are now equipped to reduce air pollution. 
Yet the industries that produce raw materials, the car and the 
gasoline to run them still lack adequate emission controls. 
Some cities may have cleaner air but industrially polluted air 
may be affecting distant lives and landscapes, even in other 

Little fresh water in settled parts of Canada is fit to drink in 
its natural state. Raw sewage still enters major waterways 
and mercury contamination renders fish in some watersheds 
unfit for human consumption. International waters are 
affected. In a country that controls more than ten percent 
of all fresh water in the world, yet has only half of one percent 
of total world population, such conditions are inexcusable. 


During recent days, reports of poisoned air and death in Los 
Angeles, unfit and deteriorating water quality in the Great 
Lakes, and declining quality of prairie lands indicate that 
everything we depend upon is deteriorating and at risk. Who 
is naive enough to think that we are immune? 

The ecology of an entire continent has been changed in little 
more than two centuries. 

We have received warning of serious environmental trouble 
ahead. Declining quality of our habitat, endangered life 
forms andthe rising cost of obtaining resources from the earth 
are alarm bells ringing loudly. 

Wild living things respond to degrading habitats by dying same 

or leaving. We have witnessed declines, decimations and 
extinctions. We foresee many more, soon. These foretell that 
all life, man included, is vulnerable. : 


by M.j. Harvery Department of Biology 
Dalhousie University 

here is the famous story of King John of England (of Magna 

Carta fame) who, in 1216, was crossing the Wash, a large 
saltmarsh in eastern England, when a part of his retinue was 
trapped by the rising tide and great deal of gold and silver, 
and all of the crown jewels were swept away and lost forever. 
The jewels are still there, deeply embedded in one of nature’s 
own treasures — the saltmarsh. The story of King John 
concentrates on the people involved. It doesn’t tell you about 
the natural wonder of the marsh world and its importance to 
the existence of many life forms on earth. : 

A mire or marsh is any wet area of ground that forms 
wherever the lie of the land prevents water from draining away 

_easily. If the water is fresh, then a range of wetland areas can 
form, ranging from grassy and sedgy wet areas (fens) to © 
bogmoss dominated areas (bogs). However, there is another 
type called saltmarsh which forms where the shelter of a bay or 
estuary allows certain plants to grow undisturbed by the 
more powerful waves of the sea. 

Growth of the saltmarsh is by a filter mechanism; the eaves 
and stems of the plants slow down the water as it passes — 
through with each tide, allowing the particles in suspension to 
settle to the bottom. The roots and rhizomes then complete 
the job, binding the loose mud into a strong mass by growing 
through it and forming a network. The mud is made up of 
mineral particles, bacteria, living and dead parts of plants and 
animals, and water containing dissolved salts. Of course, this 
type of build-up goes on in fresh as well as saltwater; the 
saltmarsh differs in having the water level fluctuate with each 
tide and in having a much higher concentration of salts. These 
conditions place a special strain on survival, and only a 
limited number of plants and animals can stand the physical 
and chemical stresses. 

The age of most of the saltmarshes of Canada and the 
northern USA cannot be older than the end of the last glacia- 
tion, and in most cases is younger. Since the shores became | 
ice free some 6,000 to 10,000 years ago (depending on latitude), | 
all our northern marshes started growth some time after those — 
dates. This may sound incredibly old, but when you think 
about it, it is nothing compared to most geological events. 

Anyone who has walked across a marsh, especially in hot 
weather, will be familiar with the bubbling of gas at each 
footstep and the noxious smell that arises. The major partofthe _ 
gas is composed of odourless methane and carbon dioxide. 
Appropriately enough, it is called “marsh gas” and will bu 
with a pale blue flame if collected andignited. You can actually 
do this by holding an inverted funnel with a finger over the _ 
end in a poo! to collect the gas while someone else pushes a_ 
stick vigorously into the mud below. The methane is produced — 
by a group of bacteria which decompose the remains of the — 

_ plants which bind the mud, in the absence of oxygen. 

Methane is produced vigorously only when conditions are — 

: warm. This probably accounts for one of nature’s mysteries, 
the “will-o’-the wisp”, being reported flickering over marshes 
after sunset only on warm, windless nights. To the medieval — 

mind, the will-o’-the-wisp was direct evidence of fairies, 
hobgoblins or devils, but to us it is evidence of the complex — 

_ chemistry which goes on in. the mind. Actually, we still do not 

know what causes the will-o’-the-wisp. We do know that 
methane is bubbling up, but methane, by itself, does not 
ignite spontaneously. The method by which it is ignited, if 
that is what happens, remains a mystery. The chemical 
phosphine which does ignite spontaneously in air has been | 
suggested as the agent which ignites the methane. Minute 
quantities of phosphine can be produced by bacteria, but no 

Ba tae 

chemist seems to have tested the idea. Today very few 
people have even seen this phenomenon. 

The nauseous smell of the marsh gas is familiar to anyone 
with a little knowledge of chemistry, since it is due to rotten-egg 
gas, hydrogen sulphine. Its presence in the marsh is due to 
another group of bacteria: those which use various sulphur 
compounds as part of the process of obtaining the energy 
necessary for their growth. The sulphur initially gets into the 
marsh from the sea in the form of sulphate ions which are 
present in seawater. The bacteria reduce them to sulphur or 
to hydrogen sulphide as part of their metabolism, which has 
several interesting effects. Since hydrogen sulphide is toxic, 
the mud itself becomes poisonous and only organisms which 
can withstand the toxicity can survive. This severly restricts the 
number of plants and animals which can live on the marsh. The 
problem is partly the lack of oxygen below the mud surface 
where bacteria keep the mud oxygen free (anaerobic). Only 
organisms which can get around this oxygen deficiency can 

Before mentioning the ingenious tricks that plants 
and animals use to obtain oxygen, one group of bacteria 
should be mentioned which actually use up the hydrogen 
sulphide, thus extending to the bacterial world the old adage 
about one man’s meat being another man’s poison. These 
bacteria are the purple sulphur bacteria, and although an 
individual cell is visible only through the microscope, they 
become so abundant in pools and on the mud surface in 
summer that they sometime form a pinkish-purple film. They 
are photosynthetic, using a chemical reaction so strange 
that it is thought likely that it is a survivor from the early history 
of the earth at the time when there was no oxygen in the 
atmosphere and the only organisms were bacteria. 

To start with, oxygen is poisonous to the purple sulphur 
bacteria, but they require hydrogen sulphide -— the complete 
reverse of almost all other organisms. They obtain hydrogen 
sulphide and carbon dioxide from the mud, and energy from 
sunlight. Using these chemicals and their own special 
brand of chlorophyll, they produce carbohydrates using 
carbon dioxide and the hydrogen from hydrogen sulphide. 
The sulphur, which is a waste product, accumulates as a whitish 
powder and eventually is used by the non-photosynthetic 
sulphur bacteria mentioned earlier. So you see, the mud of 
the saltmarsh is one vast chemical factory changing carbon 
dioxide to carbohydrates to methane and back again to carbon 
dioxide (the carbon cycle), and sulphate to sulphur and 
sulphide and back again (the sulphur cycle). Now it is time 
we pulled ourselves out of the mud and looked at the plants 
and animals. 

Saltmarshes provide excellent examples of zonation along an 

environmental gradient. The lowest plant on the shore is the 

eelgrass, Zostera, growing from below low tide mark to 

halfway up the shore. It has the distinction of being the only 

flowering plant in the north which can carry out its life 
cycle entirely submerged in salt water, the most unusual 
adaptation being that its pollen floats in seawater and is carried 
_ by current to the stigmas of the female flowers. Next up the 
gradient is cord grass, Spartina alterniflora. This is the most 
conspicuous and abundant grass on the marsh and it is 
responsible for most of the mud accumulation and produc- 
tivity. It grows in the zone of hydrogen sulphide production 

and hence its roots may extend into anaerobic mud. It gets 
over this difficulty by ingeniously having air channels in the 
roots, thus supplying oxygen and taking away the carbon 
dioxide produced in respiration. It also has nitrogen-fixing 
bacteria associated with the roots, and it excretes salt on the 
leaf surfaces, getting rid of salt absorbed by the roots. These 
tricks seem to account for its dominance on the shore. 

The remaining plants are usually less abundant. The smaller 
cord grass, Spartina patens, forms a finer turf just above the 
previous zone and nearby is the blue-flowered sea lavender, 
Limonium, which also excretes salt from microscopic glands 
on its leaves. Nice to eat is glasswort, Salicornia, sometimes 
called marsh greens. The plants look like miniature organ-pipe 
cacti and accumulate salt in the tissues which accounts for the 
pleasant flavour. Salicornia also occurs inland around salt lakes. 
The upper parts of the shore around high tide mark have a 
greater variety of less specialised plants since the stresses of the 
tide salt and anaerobic mud are less. 

The problems that animals face in the mud are similar to 
those facing plants, especially the need to obtain oxygen. 
Clams, for instance, often bury themselves in anaerobic mud 
but obtain oxygen and food particles by their system of 
syphons which draw aerated water down to the animal. Salt- 
marsh mosquitoes deserve a mention if only because they bite 
harder than others. Their larvae live in the pools of water (pans) 
on the upper marsh feeding on plankton in the water. They are 
not troubled by any shortage of oxygen in the water since they 
wriggle to the surface and fill their tracheae with air. Some 
current research is aimed at ‘mosquito control’, but many 
scientists consider this to be misdirected science, since 
mosquitoes are part of the food chain. To eliminate them cuts 
off a portion of food to the animals that feed on them. Better 
clothing or repellents may be the answer. During the 1950’s and 
60’s, many marshes were sprayed with DDT and other 
insecticides with disastrous results to some bird populations. 
Their effects on humans are still unassessed. 

Are saltmarshes threatened? They certainly are. The first 
threat was agricultural. In the Maritimes, the Acadian settlers 
created fertile farmland by constructing dykes around the 
marshes to keep out the sea, converting the landto non-saline — 
hay and pastureland. Approximately 10,000 hectares of = 
undyked marsh out of an estimated 30 ,000 hectares still exist = 
around the Bay of Fundy. rae 
Now-a- days the threat is not agricultural bu 

fae level land. A common way of obtaining t s is to dump = : 
fillon the | local marsh ices in this way the edges of many 

yo ciated i one ioe Hoveve: | in this case the new eS 
owners belatedly discover the marsh mosquitoes and put 
enormous pressure on the local authority to spray or drain or 
do anything to get rid of the the insects. Sewage is another 
threat; many marshes are now closed to clam digging because 

of bacterial contamination. 

The non-destructive uses to which saltmarshes are put 
include general recreation, birdwatching, hunting, clam- 
digging and cranberry picking. The Micmac Indians collect 
sweetgrass, Hierochloe odorata, from saltmarshes for weaving 
into baskets which have a sweet, vanilla-like odour. 

It is also possible to regard saltmarshes as vast chemical 
factories, taking chemicals from the land, the sea and the air, 
changing them into other important substances. It has slowly 
come to be realized that the salt marshes play a key role in 
maintaining the fertility of the entire costal region. Organic 
matter, produced by such plants as the grass Spartina, passes 
from organism to organism along a complex food chain, and 
residues of this are eventually exported into the surrounding 
coastal waters. This is one of the important factors which make 
coastal waters so much more productive than areas of the open 
ocean. Apparently Spartina is one of the more efficient plants 
of the temperate zone at converting the sun’s energy into 
organic matter. Just exactly what happens to this organic matter 
and just how it gets into the sea are topics under investigation 
by teams of specialists applying the principles of trophic 

One must also recognize the importance of saltmarshes to a 
group of animals that are not present much of the year: the 
geese and some species of ducks. These depend absolutely on 
the existence of a chain of marshes connecting their wintering 
grounds to their nesting areas. They must have a series of 
relatively undisturbed stopping points of sufficient size to 
enable them to migrate. If a large number of marshes are 
eliminated, the annual migrations will be put in jeopardy. 

Rare Plants and 
Their Habitats 

by George W. Argus 
National Museum of Natural Sciences 

t is often difficult to be heard when we talk about the 
importance of rare plants and their habitats, or about the 
threats to their existence, because the popular conception of 
Canada is one of endless forests and plains, inaccessible 
mountains and avast Arctic wilderness. But, even in our large 
and sparsely settled country, we are, year by year, increasingly 
modifying our environment. Many natural habitats are now 
suffering from misuse. Fortunately, there are people who are 
aware of what is taking place and who are examining the 
consequences of our actions. There is a growing understanding 
of the ecological fact that a decline in the abundance of a 
species, or its extinction, is a reflection of environmental 
deterioration. Giving some thought to rare plants and some 
of the threats to their existence can help us understand what 
we must do to prevent a decline in the quality of our life in 

We find it useful to direct our attention to rare plants for 
several reasons. Rare plants often indicate the occurrence of 
a unique set of environmental conditions. These may be 
uncommon habitats such as bogs, marshes or active sand 

dunes. They may be mountains where plants were able to 
survive the ice ages, or they may be places where plants are 
evolving into new types. 

Some rare plants are the survivors of widespread vegetation 
that once covered parts of Canada, but that has been largely 
removed or changed by our activities. If we study changes 
in populations of rare plants, they can be used as a kind of 
early-warning system to tell us when we are seriously altering 
our environment. 

An understanding of rare plants can best start with the end of 
the ice ages in Canada, about 10,000 years ago. At that time, 
the ice that had blanketed Canada, with the exception of a 
few areas, or refugia, was receding. The plant life that we see 
here today slowly became established as plants moved across 
the newly exposed landscape from southward and from 
places where they survived (refugia) in central Alaska and 
the Yukon, and from smaller refugia on both coasts. Rare plants 
in Canada are therefore the result of many factors, including 
different times of arrival and rates of travel, the survival of 
plants in certain refugia, inability to compete with more 

aggressive species, the adaptation to new habitats that 
sometimes lead to the evolution of new species, and human 
modification of the landscape. 

Some rare plants occur over large areas but are scarce 
wherever they occur. These plants are usually confined to 
localized, unique habitats such as wet limey meadows (the 
habitat of the small lady’s-slipper) or limestone cliffs (the 
habitat of the smooth cliff-brake fern). It is difficult to know 
just how abundant such widespread, rare plants are because of 
their scattered occurrence. Some plants that we call 
widespread, rare species may be more common than we think. 

Other rare plants occur only in small geographical areas and 
may represent one of a number of types of rarity. Some may 
be the last representatives of a plant life that once was much 
more common (relict species), others may be newly evolved 
species, and yet others may be plants at the edge of the main 
range of a species that just barely extends into Canada. 
Examples of the last category of rare plants occur all along the 
border of the United States. These plants are of particular 
importance because they represent the advancing front of 
species that are adapting to a more northerly climate. The 
genetic types represented by these new immigrants are 
valuable breeding stock for Canada. 

In southern Alberta, many rare plants from more southerly 
mountains fall within Waterton Lakes National Park and 
are protected there. In southwestern Ontario, the once 
widespread deciduous forests (containing many species from 
the Appalachian Mountains) have been generally cleared for 
agriculture, industrial development and for cities. Certainly 
we need land for these purposes, but surely there must also 
be places in Canada for dense forests of magnolias, tulip trees, 
black gum trees, oaks and maples. Such forests are now found 
only as isolated woodlots. 

The grasslands of Canada have suffered a similar fate. The 
tall-grass prairie has been largely replaced by grain fields. In 
Manitoba, there are only three known tall-grass prairie 
sites left, the largest of which is only 100 acres. Whether a 
grassland of this size can long survive is questioned by some 
ecologists. Some grassland species in the drier mixed-grass and 
short-grass prairies of Saskatchewan and Alberta exist only 
in coulees, along rivers or on poorer prairie land. Some of 
these habitats are under threat from the ploughing of marginal 
land, overgrazing, replacement of natural prairie with 
community pastures seeded with introduced grasses, or from 
drainage of prairie wetlands. Fortunately, some prairie lands 
in Manitoba and Alberta are being protected as natural areas. 
However, attempts to set aside a grassland in the southern 
part of Saskatchewan have met with much opposition and 

Because the flora of Canada is so young (less than 10,000 
years old) there are not many areas where evolution has 
resulted in new species. The presence of new kinds of plants 
in some areas tells us that here are unusual habitats of great 
scientific and educational value. One of our best examples is 
the great inland sand dune region in northwestern Saskat- 
chewan. Here the unstable sand dune habitat has given rise to a 
number of new kinds of plants. 

On the mountains of both the Gaspé Peninsula in Quebec 
and the Queen Charlotte Islands in British Columbia, there 
are refugia, or places where plants survived the ice ages. 
They sustain many rare plants, including some new species. 
Since these areas are also of scenic and recreational value, we 
must make sure that our use of them for these purposes does 
not threaten rare plants or the habitats that gave rise to them. 

In some places, there are rare plants with no obvious reason 
for their location. For instance, the Furbish lousewort, an 
attractive herb, appears to exist only in the upper St. John 
River valley in western New Brunswick and in northern Maine. 
It is protected by law in Maine, and a dam that would have 
flooded its habitat has been prohibited. This plant is also 
threatened in New Brunswick by the construction of dams, but 
the law that could protect the species has not yet been used. 
We hope that before long this plant will be protected in 

During the past few years, most provinces have passed laws 
that could be used to protect rare plants and their habitats. 
Some provincial and national parks are giving protection to 
unique plant habitats. 

Most of the laws needed to protect rare plants are already in 
place; all that seems to be lacking is a sense of urgency. Not 
enough people are convinced that natural habitats are really 
important. Governments should be providing coordination 
and direction, scientists should be providing information, 
and people should be pressing for conservation action. 

There are reasons for being both optimistic and pessimistic 
about the future, but any action that is taken, no matter how 
small, to prevent the loss of species or habitats tells us that 
some people are heeding the message. They know that the loss 
of aspecies is a sign of environmental deterioration that cannot 
be ignored long — because it is our environment as well. 

Arctic Landscape 

by Richard Passmore 

f one were to travel northward from any part of the rather 

narrow strip of populated, developed area that crowds 
against the southern border of Canada, the first few hundred 
kilometers of the journey would be quite variable, depending 
on thestarting point. But sooner or later, one would enter 
the broad band of boreal forest, dense and somber in its 
heavy growth of spruce, fir, and pines, that stretches across 
the breadth of the country. Continued northward travel would, 
however, proceed through forests in which trees are shorter 
and more widely spaced until the last of the stunted spruces 
lies behind the traveller who now looks northward over a 
treeless, undulating plain dotted with ponds and lakes. This 
is the tundra, typical of the Arctic landscape that occupies 
about one third of the land mass of Canada. 

Not all of the Arctic landscape is flat. It may be ruggedly 
mountainous, or covered by thick glacial ice-caps. It may 
occur well south of the Arctic Circle (66°30’ north latitude) as in 
the vicinity of Churchill, Manitoba, and in northern Quebec 
and Labrador. Typically Arctic vegetation clothes the upper 
part of high mountains in more southerly latitiudes. Con- 
versely, the relatively sheltered MacKenzie Valley supports 
sub-Arctic forest growth well north of the Arctic Circle. It 
is the tundra vegetation — a mix of grasses, sedges, lichens, and 
low-growing shrubs — that gives a degree of uniformity to the 
Arctic landscape. 

A number of climatic factors combine to give the Arctic 
tundra its characteristic appearance. In terms of precipitation, 
the Arctic is a cold desert with total annual precipitation 
averaging only a few centimeters in the drier locations — yet 
few places suffer from insufficient moisture to support growth. 
The incredibly dwarfed shrubs reflect another aspect of the 
climate — the fierce winter winds that drive icy pellets against 
bark or buds exposed above the snow. Only those shrubs 
growing in the lee of sheltering objects, or those covered by 
snow drifts, can achieve heights that greatly exceed that of the 
general vegetation mix. 

The tundra is greatly influenced by the fact that it is underlain 
by permafrost (permanently frozen ground) which occurs 
wherever the mean annual temperature of the surface of the 
ground is lower than 0°C. Freezing of the soil, which may 
have taken place several thousand years ago in some areas, 
and which has proceeded to depths as great as several hundred 
meters, brought about great changes in the moisture (ice) 
distribution within the soil. Soil that contained considerable 
moisture at the time of freezing may now contain ice of varying 
dimensions, or massive accumulations of clear ice of various 
sizes and shapes. 

The warmth of the summer sun (lasting 24 hours per day, fora 
few weeks) induces thawing of the soil to a depth of half a 
meter or so. Moisture is released to permit a remarkable 

outburst of vegetative growth. Soon the leaves, flowers and 
fruiting bodies of a variety of plants combine to produce a 
colourful scene whose real beauty becomes apparent only 

upon close examination. 

Annual thawing and re-freezing of the ‘active layer” also 
contributes to development of the “‘patterned ground” which 
is so characteristic of Arctic tundra. These patterns are some- 
times strikingly apparent when viewed from the air. 

Although the general level of biological activity is low, the 
Arctic landscape is home to asurprising variety and abundance 
of wildlife. Lemmings, ptarmigan, arctic hares, barren-ground 
caribou, muskoxen, arctic foxes, birds of prey, arctic wolves 
and barren-ground grizzly bears make up the significant 
resident fauna of the tundra. Local concentrations of one 
species, particulary the caribou, may, at times, be spectacular. 
Spectacular too, is the number and variety of migratory birds 
which nest in the Arctic and, following a short period of rapid 
growth of the young in the continuous daylight of the Arctic 
summer, migrate southward again with the approach of 
autumn. Outstanding among these long distance migrants is 
the arctic tern which rears its young in the High Arctic and 
then returns to the Antarctic to enjoy the summer season in 
the southern hemisphere. 

The short, dense, spongy mat of vegetation of the tundra 
provides excellent insulation for the frozen soil which 
underlies it. A delicate balance between inflow and outflow 
of heat from the soil preserves the permafrost and, most 
importantly, maintains any massive ground-ice structures in 
their frozen condition. This balance can be upset by distur- 
bances as minor as trampling or compressing the tundra 
vegetation. More serious disturbance of the insulating vegeta- 
tion can have devestating consequences as soil thaws and 
ground-ice melts. Resulting erosion channels can leave 
permanent scars on the landscape and may seriously interfere 
with wildlife populations. 

The sensitivity of the Arctic landscape to serious long-lasting 
damage has become all too apparent, in recent years, as 
Canadians have sought to develop some of the resources of the 
Arctic. Is there really such urgency that inappropriate or 
untested technologies, with all of their potential for long term 
damage, must be pressed into immediate use? Future develop- 
ment in the Arctic must avoid the risk of disturbing delicately 
balanced natural systems. And some of the more sensitive 
landscapes, and those which have particular aesthetic, historic 
or biological values, should surely be left unchanged, for the 
benefit of future generations. 

Status and 
Habitat of 
Canadian Fishes 

by Dr. D.E. McAllister and Dr. C.G. Gruchy 
National Museum of Natural Sciences 

Adapted from “Canada’s Threatened Species and 
Habitats”, Canadian Nature Federation, 1976. 

hree and a half centuries ago, when Champlain ascended 

the St. Lawrence and viewed the Great Lakes, he found 
the waters clear, alive with fish, the land richly endowed with 
plants and animals, and peopled with natives who lived in 
relative balance with nature. In Bartlett’s day in the 1800s, 
salmon could be speared by the dozen in creeks along the 
shores of Lake Ontario. Today, many rivers are cloudy with 
eroded soil carrying invisible synthetic chemicals. In place of 
trout, whitefish and walleye we have bullheads, suckers, 
introduced carp and lampreys. The story of changes in the fish 
fauna of the Great Lakes is repeated in different ways for 
many of Canada’s southern rivers and lakes. 

In some ways catastrophic accidents such as the wreck of 
a supertanker are worse than gradual changes. Slow 
deterioration of environmental quality such as gradual 
deforestation, siltation and decrease in fish population is 
insidious because one adapts to it. It is only when we contrast 
past and present we become aware. The hereditary chief of the 
Children of the Sea Foam, Chief Pachena of Port Renfrew, 
British Columbia, who celebrated his 100th birthday 7 July 1976, 
said of his band: “At one time the people — more than 1,200 — 
could live on fish and game. Now the few of us left would 
starve if we tried to do the same.” 

Of Canada’s native fish fauna, we know that at least two 
species are extinct in our waters, nine species or subspecies 
are at the edge of extinction, six are likely to become 
endangered and 19 are so rare that they could easily be wiped 
out. Seven of these 36 forms are found only in Canadian waters. 
About half of the remainder exist in an equally precarious 
condition in adjacent areas of the United States. 

We suspect that other species were lost before we began 
studying Canada’s fish fauna. We know that the once abundant 
lake sturgeon is still on the decline. The little known 
deepwater sculpin, once numerous in the depths of Lake 
Ontario, has virtually disappeared. No one knows why. 

It is obvious that knowledge of the taxonomy and 
distrubution of Canadian fishes is incomplete. We are still 
discovering species of fish previously unknown in our waters. 
The need for a thorough zoological survey of Canada is 
evident. In reading Scott and Crossman’s (1973) monumental 
volume, The Freshwater Fishes of Canada, one is struck by 
the absence of habitat studies for noncommercial, non-sport 
fishes. They state: “It is the hope of the authors that this text 
will perform a useful service by highlighting the lack of 
information on many aspects of the biology of many Canadian 
fish species. Particularly glaring is our (lack of) knowledge of 
the basic life history of many common species.” 

Deterioration in habitat has affected 18 forms of fishes, 
introduction of exotics eight forms, overfishing seven forms 
and dams two. Some fish have been affected by two or three 
factors simultaneously. For example, ciscos of the Great Lakes 
have been reduced by overfishing, introduction of alewife and 
sea lamprey, pollution and eutrophication of lakes. 

Habitat is one of the most critical factors in the survival of 
a species. For fishes, the elements of habitat that must be 
considered include water clarity, water temperature, oxygen, 
vegetation shelter, type of bottom and the absence of toxic 
chemicals. Equal consideration must also be given to boulders, 
gravel, sand or mud, seasonal water flow and depth, absence of 
obstructions, presence of pools or riffles, shade, leaf fall, 
competition, parasites, predators, food supply and spawning 
substrate. The effect that one biotic factor may have on fish 
populations can be illustrated by trees. Trees provide shelter 
and shade; they moderate temperature and runoff. Indirectly, 
they are also the source of food. Nearly half of the food of 
young coho salmon in an Oregon study consisted of terrestrial 
insects, most from the forest. Another study showed that thirty 
per cent of primary invertebrate food in a Pennsylvania creek 
came from detritus such as leaves. The leaves are broken 
down slowly by bacteria and fungi. The latter are fed upon by 
invertebrates, which in turn serve as food for fishes. 

Farms and logging operations influence habitat more than 
any other industries because of their effect on tree cover. 
Provinces should pass laws which would ensure that logging 
companies leave a 10 metre buffer strip of untouched trees on 
either side of streams, and that logging roads (which can 
cause heavy siltation) are constructed outside of the buffer 
strip. Farmers should also be given incentives to leave similar 
buffer strips, and provide for restricted access to streams 
by cattle. 

The rage for exotic fauna and flora has led to many 
introductions, such as the carp, to North America. The effects 
of these introductions on native fishes are exceedingly 
complex and have had undesirable effects. For example, 
aquarists introduced tropical fishes into a hotspring at Banff, 
threatening endemic subspecies of dace. The planting of 
normal brook trout in lakes inhabited by aurora brook trout 
led to the loss of that subspecies through hybridization. The 
introduction of several species into the Great Lakes, in 
combination with environmental disturbances, has made 
good management difficult. 

It is of course possible to restore fish habitat. Fish are running 
again in the Thames River in England, a river that was so badly 
polluted that the stench forced the adjournment of Parliament, 
which is located on the banks of the river. 

More nature reserves could be created for rare, threatened 
or endangered species. British Columbia was one of the first 
provinces to establish a reserve especially for a fish — Drizzle 
Lake in the Queen Charlottes for the giant stickleback. 

In southern British Columbia one can find unique species of 
fishes that apparently spread there after surviving the 
Wisconsin glaciation in Washington. Several species also 
survived in the upper Mississippi region and now occur in 
southern Ontario. Fishes that survived in the Beringian region 
are now found in the Yukon. In the Milk River some species 
came from the presumed Missouri refugium, and in New 
Brunswick and eastern Quebec from the Atlantic coastal 
refugium. A number of species spread to New Brunswick 
and eastern Quebec. These areas would be priority candidates 
for reserves, each with its own management program. Similarly, 
species-rich regions could be selected for each of Canada’s 
three coasts. 

Likewise, a new type of natural history reserve could be 
established for the continental shelf and slope. Besides their 
normal role in preserving living samples of marine faunas, 
these reserves would enable scientists to check on the effects 
of trawlers fishing off Canada’s coasts, and the soon to be 
expected marine mining operations. These reserves could be 
indicated on marine charts for fishermen, just as underwater 
city garbage dumps and munitions disposal sites are presently 

What is less obvious is that reserves should be set up to 
preserve as much as possible of currently non-threatened 
fauna and flora. It is much more difficult to save the last 
remnant of a species. 

Prairie Wetlands 

by W.G. Leitch Ducks Unlimited (Canada) 

Prive wetlands, those semipermanent ponds that dot 
the prairies and parklands, come in many shapes 

and sizes. They vary from temporary field ponds, farmed 
in all but the wettest years, to those that hold water all 
year except for periods of extreme drought. Some are 
open-shored, surrounded by cultivation or grassland, 
others are rimmed by low willows or groves of poplars. 

Individual wetlands differ greatly from year to year, 
depending on the runoff into them from spring snow 
melt and rainfall. In the spring they may be flooded, 
partly filled, even dry, and, depending on the year 
may be dry or filled again by fall. In wet years, the deeper 
larger areas may resemble small lakes, with an extensive 
expanse of open water. In average years the same area 
may be marshlike, with thick and wide-spread stands 
of bulrush and cattail, while in years of drought, it may 
be dry and dominated by dry, land plants. 

But for all their variety, prairie wetlands have one 
thing in common — high fertility — and the abundant 
plant and animal life associated with it. 

As might be expected, the plants and animals associ- 
ated with prairie wetlands are remarkably well adapted 
to changing conditions. Floods retard the growth of 
shallow water plants, yet these plants retain a foothold 
on the shallower margins until lower water returns 
when they spread through the wetland once more. 
Furthermore, their seeds are drought resistant 
and can remain fertile through many dry years until 
conditions are again right for growth. The many kinds of 
small animals which swarm in their millions in a fertile 
wetland are wholly dependent on water and cannot 
move elsewhere as waterfowl and muskrats do when the 
pond dries up. These creatures have adapted to dry 
periods by producing drought resistant eggs which can 
remain alive through many dry years. 

This is one of the wonders of wetlands. How, after 
years of drought, they can so quickly teem with life once 
water returns. 

Each species of bird and animal uses the wetlands in a 
different way. Their demands for food and space are 
seldom in serious conflict. Each utilizes a particular 
part of the wetland; each has its own place. 

For example, different kinds of ducks are adapted to 
feed primarily in particular parts of the wetland and 
though there is some overlapping at times, any or all of 
the food sources can be used. Thus some feed on the 
small animals near the surface of the pond straining them 
out of the water with their specially designed bills. 
Others feed on the seeds, leaves and stems of aquatic 
plants growing at and below the surface of the water 
or on the small animals associated with them. Still 
others dive for the animals and seeds buried in the 
bottom muds. 

Grebes live in the open water and build wet soggy 
nests from floating vegetation. One wonders if the eggs 
will ever survive to hatch — but they do. Black terns 
skim over the water picking up their food at the surface; 
building their nests almost at water level, defending 
them bravely with much noise and excitement and 
occasional sharp pecks on the head of an intruder. 
Shorebirds probe the wet mud edge for food and nest 
along the shore. 

At the edge of larger ponds the great blue heron 
stands motionless, silently awaiting the passage of an 
unwary minnow or frog. The noisy but musical, red- 
winged and yellow-headed blackbirds nest in the 
bulrush and cattail edge. Muskrats build their houses, 
raise their young and forage for food in the same edge; 
remaining active under the ice through the long winter. 

As you can see — a wetland is exciting and changeable. 
In short — if you want action — a wetland is where it’s at! 

When looking at a wetland with its associated birds 
and animals, there is little evidence of the multitude of 
tiny plants and animals, the complex biological pyramid, 
which supports so much obvious activity. All you see 
is the tip of the pyramid, the top of the iceberg, so to 
speak. The rest, and perhaps the most interesting, is 
hidden from the casual eye though partially apparent 
if one looks more closely. 

A whole fascinating world, swarming with life, lies in 
the water. A world almost separate from that around 
us yet profoundly influenced by it. One with its own 
prey and predators, food chains and pyramid of 
numbers, where the strong prey on the weak as they 
do on land. 

To begin at the beginning requires a microscope, 
and, even before that, a chemical analysis of the water. 
For the variety and abundance of plants and animals 
depends very much on the fertility and other chemical 
characteristics of the water and bottom muds. If the 
wetland is on fertile soil, or if the water moves across 
or through fertile soils enroute to the wetland, then the 
fertility of the pond will be reflected in an abundance 
and variety of aquatic plants and animals. 

Infertile waters will produce fewer plants and animals 
both in numbers and diversity. Those that do exist 
will be particularly adapted to the special conditions 
which the infertility, or other characteristics, of the 
particular water body imposes. 

One of our present problems can be excess fertility 
resulting from pollution from several possible sources. 
Human sewage, animal wastes and extensive use of 
fertilizers on the surrounding uplands are the common 
ones. Over fertilization favors primitive plants which 
can quickly utilize high concentrations of nutrients. 

An imbalance occurs in the wetlands and it becomes 
dominated by algal growth which is pleasing neither to 
the eye or nose of human beings. 

Pollution of a different kind results when poisonous 
wastes, usually from an industrial source, are discharged 
into a wetland. All the plants and animals in the water 
may be killed and the birds and animals dependent 
on them die or forced to leave. The wetland becomes 
silent and dead. 

An unpolluted wetland is a thing of beauty with clear 
water, bright plants and abundant life — visible and 
invisible. Something to be cherished and protected. 

In the water as on land, plants both large and small, 
are the base on which all the animals depend. Many 
plants are extremely small, microscopic in size, and enter 
the food chain at that stage. Other plants are larger and 
easily seen. Typically these larger plants occupy 
characteristic zones in and around a wetland. 

Some plants are completely under water while the 
leaves of others may just reach the surface or float upon 
it. In shallow water or along the shore, the emergent 
plants are found. These include the well known cattail 
and bulrush and are called emergents because, although 
they grow in two or three feet of water, most of the 
plant stands erect above the water line. Further shore- 
ward are the wetland grasses and sedges which soon 
disappear when the water becomes too deep. 


On this plant base, large and small, is built the animal 
community, only the larger members of which we 
usually see. The perch or pike we catch in a larger 
wetland is at the top of a long food chain which began 
with small microscopic plants which were able to use 
the fertility of the water and the energy of the sun to 
produce plant tissue. These plants were utilized by small 
organisms playing the same role as grazing cattle and 
other herbivores on land. These were preyed upon by 
larger animals in the same way that foxes prey on mice. 
Each successive predator became prey, the larger ate the 
smaller until the top of the chain was reached with 
the pike or perch. In smaller water bodies which contain 
no large fish, the top of the chain may be missing, but 
the other links are present. 

Some food chains are short. Thus the muskrat 
performs his role as a herbivore feeding on the roots 
and shoots of emergent plants. In turn, he is a prey 
species for mink, coyote and predaceous birds. 

In the same sense that we have animal communities on 
the land, in the trees and in the air, so we have similar 
communities in water. Distinct animal communities are 
associated with the bottom muds, the submerged and 
floating leafed plants and the emergent plants along 
the edge. 

Animals associated primarily with the bottom muds 
are called benthos or benthic animals. These include 
the well known clams, aquatic worms and some larval 
insect forms which are free flying when adult. The 
dragonfly is one of the best known examples of the 

Other organisms large and small, prey and predator, 
make their homes in the dense stands of submerged 
and floating leafed plants — a situation similar to the 
forests on land. These are animals of many kinds and are 
collectively known as plankton. Like birds, they may 
leave the shelter of their underwater forest to swim 
through the open water. 

Look then at a wetland with wonder. It is a fascinating . 
world — one waiting to be enjoyed once you have the 
keys — and the keys are curiosity, knowledge and awe 
of its beauty and complexity. 

From what has been said so far, it is clear that prairie 
potholes enrich our lives. Their endless variety gives 
beauty and charm to the landscape. The wildlife 
associated with them adds excitement. Bird watching, 
even casual observations, hunting and just the unique 
aquatic situation all provide recreation. Water seems 
to have a fascination for all of us. We come to accept 
all these things as part of our daily lives without really 
being aware of them, their value to us, and how poor we 
would be without them. 

include stabilization of runoff and reduction of erosion 
and flooding both local and distant. It makes little sense 
from a national viewpoint to drain water from local 
upland wetlands and flood rich bottom lands elsewhere. 
Large scale wetland drainage can also have significant 
adverse effect on ground water supplies. Wetlands 
supply water for farm use. In years of drought, last year’s 
wetland may well be the only source of this year’s hay. 

Land owners who preserve their wetlands are public 
benefactors and should be recognized as such. Unfor- 
tunately, wetlands seem to pose a challenge to many 
land owners — a challenge to their sense of neatness 
and efficiency — and they are destroyed by draining, 
filling and burning. 

It is time we realized that the pioneering era is over. 
Our objectives should no longer be to conquer the land 
but to learn to live with it. If we do not soon learn 
nature’s lessons, it will be to our everlasting sorrow 
both from practical as well as aesthetic points of view. 

When the prairie potholes and the wildlife associated 
with them are gone, the prairie landscape will be dreary 
and all of us much poorer in both spirit and pocket. 

National Parks: 

Protection of Endangered 
Habitats and Wildlife 

by Dave McBurney National Parks Branch 
Department of Indian and Northern Affairs 

F iction writer Ray Bradbury once wrote a short story about 
time machines, entitled ‘““A sound of thunder”. You may 
remember it. The story involved a safari company of the future 
which offered hunters trips into the past to hunt dinosaurs. 
Everything was always meticulously planned to ensure the hunt 
would not interfere with events of the past. Hunters and guides 
walked only on special boardwalks which hovered above the 
ground and dinosaurs were always shot the instant before 
they would have died of some natural cause. You can probably 
guess how the plot develops. 

On one ill-fated trip, an overzealous hunter ventured off the 
boardwalk and accidentally stepped on a rare species of 
butterfly. Travelling back to the present, the group find to their 
horror that the world they left had changed dramatically — all 
from the loss of one butterfly and the influence of several 
million years. 

An exaggeration? Perhaps, but just how much of an 
exaggeration is it today where man’s detrimental impact on 
wildlife habitat far exceeds the misadventures of one butterfly? 


If you could, how far would you venture into our future? Will 
the whooping crane and wood bison be extinct in 100 years? 
Will suitable habitat for salmon, beaver and elk exist 1000 years 
from now? Answers to these questions will depend largely on 
action taken today to protect wildlife habitat. This is an area in 
which both national and provincial parks play an important 

Since parks do serve several purposes, they cannot be 
considered as nature reserves in the strictest sense. However, 
when threatened habitat is known to occur within a park it is 
given the highest degree of protection possible. Size is one 
aspect of national parks which is important in the preservation 
of the habitat of several species, particularly those which 
undertake extensive migrations or are wide ranging in their 
habits. Twenty of our 28 national parks exceed 259 square 
kilometres in area, and each of our five largest parks exceeds 
6,475 square kilometres. 

The mountain parks are particularly important to preserva- 
tion of the larger predator species — wolf, cougar and grizzly 
bear. It would be unrealistic to expect the re-establishment 
of these species over much of their former range. Attitudes 
developed in association with agricultural land use are difficult 
to change, and it would appear that these animals will 
continue to be the object of hunting and predator control 
immediately outside the park boundaries. The wolf is 
particularly vulnerable. Recent studies indicate that population 
fluctuations in some of our parks are directly related to 
management programs of surrounding areas. 

The fact that bears are attracted to garbage and food has 
influenced their natural distribution and occasionally brought 
them into conflict with man. Increased use of wilderness 
areas is creating a similar problem, but with the roles reversed. 
There are no complete solutions to difficulties of this sort; 
however, action can be taken. Incineration of garbage and 
centralization of garbage disposal in the mountain parks 
are steps in the right direction. Continued research and 
monitoring programs should allow us to reduce the likelihood 
of undesirable encounters between bears and visitors. 
Education is a high priority, for it is less likely that anyone 
understanding bears will come into conflict with them. 

Of course, there are situations where the survival of a species 
is currently in doubt and visitor access must be restricted. 
Perhaps the best known example is the whooping crane which 
has been on the edge of extinction for many years. Their 
only known nesting grounds were found in Wood Buffalo 
National Park in 1955 and, since then, they have been strictly 

Often, protection alone may not be sufficient to ensure the 
survival of a threatened species, and active manipulation may 
be required to maintain or restore a particular habitat type. 

Yet the effectiveness of a management program can only 
reflect our knowledge of the processes involved. While our 
understanding of some of the interactions between certain 
species and their habitats are well documented, our overall 
knowledge is fragmented. We do not fully understand the 
complexity of any natural ecosystem. Consequently, any 
attempt to reintroduce a species, restore habitat or maintain it 
at a particular stage, must be approached with caution 

since changes in any part of an ecosystem will alter the system 
as a whole. Let’s consider an actual example. 

The woodland caribou was once abundant on Cape Breton 
Island but, following a series of declines, it disappeared early 1900’s. However, a part of its habitat 
had been preserved within the boundaries of Cape Breton 
Highlands National Park and, in 1968, it was decided to 
reintroduce a herd of 51 caribou. Within five years the herd 
had disappeared. It now appears likely that the caribou were 
killed by a herve disorder caused by a parasitic roundworm. 
In its normal life cycle, the worm parasitizes white-tailed deer 
and is seldom fatal. Over the years, timber harvesting had 
changed the forest cover in the surrounding region. The new 
growth of trees created habitat favourable to deer and 
consequently, their range extended northward, introducing 
it and the parasite into the park. Caribou appear to have 
entered into the worm’s life cycle, replacing the deer as the 
final host and, unfortunately, in caribou, the resulting infection 
is usually fatal. While it is ironic that this relationship was 
not fully understood until after the reintroduction, it is more 
important to realize that such very subtle changes to a species’ 
habitat can threaten its survival. . 

As you Can see, preservation of endangered habitat is seldom 
a simple, straightforward task. Parks do have a valuable 
contribution to make. However, the future status of wildlife 
habitat will ultimately depend on the cooperative efforts of 
government agencies, the private sector and conservation 
groups, with the support of the general public. Concern for the 
protection of habitats is a logical priority for all of us since 
the final question to be answered is the most ominous. Will 
habitat suitable for the existence of mankind exist in 1000 
years? Don’t rely on time machines to give you the answer. 


Univers ity of Alberta Library 


1620 58