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Wetland Basics | Ponds
| Bogs & Fens
| Pollution | Wetlands
What exactly is going on in a natural pond?
pond ecosystem consists of different tiers, with the water
forming the foundation of the ecosystem. These levels are
dependent on the other for health and growth. In the backyard
pond you create, the same relationship exists as in the
natural pond. The difference lies in human intervention to
provide plants, filtration, and fish to speed up the natural
6-tiered food chain defines your pond's ecosystem
- Bacteria, diatoms, phytoplankton,
protozoa, and plants (including algae) - In a pond you create,
your bio-filter gives bacteria a medium in which to grow so it can
turn harmful ammonia into more neutral fertilizers (see Nitrogen
- Zooplankton (daphnia and rotifers) -
These tiny creatures drift through water, feeding on algae and
protozoa from Tier 1.
- Larval insects, worms, leeches, snails,
and insects - Members of this tier consume zooplankton as well as
individuals in Tier 1.
- Amphibians (frogs, toads, salamanders,
and newts) - These consume some of the lower tiers. Salamanders
and newts frequent natural ponds much more often than backyard
ponds, but most likely frogs will find a home in your pond.
- Fish - Most fish are omnivorous, which
means they will eat just about anything. Besides any food you give
them, fish will also eat all members of the lower tiers.
- Birds, reptiles, snakes, turtles, and mammals - These
travelers are the connection to the surrounding environment, both
for natural ponds and for your backyard paradise. Although
predators may be unwanted, they do represent a vital part of the
ponds begin to age the moment they are formed. As a pond ages, the
nutrient level and amount of organic material increases. This aging
begins when algae begin to grow, releasing oxygen during the day and
carbon dioxide at night. Algae provide microscopic creatures with a
food source, and as those creatures begin to thrive and die back,
they become nutrients for higher orders of plant life. These plants
help balance the nutrients and waste and deliver even more oxygen
into the water, allowing higher levels of the ecosystem to thrive.
Zooplankton feed insects and the other creatures of tier three,
which in turn feed the amphibians in tier four. All of the tiers
below tier five help fish thrive. Fish create waste and phosphorus
(from their food) which cause plants - including algae - to grow.
Thus perpetuating the cycle.
A pond is a small area of still, fresh
water. It is different from a river or a stream because it
does not have moving water and it differs from a lake because
it has a small area and is no more than around 6 feet
deep. Some ponds are formed naturally, filled either by an
underwater spring, or by rainwater - sometimes known as
‘dewponds'; other ponds are man-made.
If a pond is to be a successful habitat it
must have plants growing in it. They provide food, oxygen and
shelter for the animals. Green plants need sunlight to make
their food (photosynthesis)
so a pond in the open will be more successful than one in the
shade. The smallest plants in a pond are the microscopic phytoplankton and these provide
most of the food in a pond. The phytoplankton and larger algae form the first part of the
pond's food chains.
Plant-eating animals - the herbivores - eat the plants and the
herbivores are eaten by carnivores (meat eating
Pond vegetation grows in areas called zones. Plants such as great
willowherb and meadowsweet grow in the bankside zone: they like damp
places but are not true water plants. The emergent plants grow nearest to the
pond edge in the marsh zone
e.g. yellow iris and mud-sedge. These fringing
plants provide good hiding places for some pond animals such
as young frogs, and the tall stems are used by dragonfly
nymphs when they climb out of the water before emerging as an
In the aquatic
zone live the truly aquatic plants. Some of them float
on the surface with tiny roots dangling in the water e.g.
duckweed and frogbit. Others have their roots
buried in the mud at the bottom of the pond and their leaves
float on the surface e.g. water-lilies and
Then there are fully submerged plants such
as starwort and Canadian pondweed. These produce
most of the oxygen so it is important that they receive plenty
of sunlight (oxygen is produced during photosynthesis). If the
plants on the surface are completely covering the pond then
some of them should be pulled out or the submerged plants will
Some species of pond plants, such as the
water-violet, are becoming very rare indeed.
LIFE IN A POND
A pond is a fascinating habitat to study, a
good one teeming with a great variety of both animal and plant
life. The community (all the
species of animals and plants present) in one pond may be
quite different from that in another, even if the ponds are
This is because most pond animals cannot
travel from one pond to another. Also the water temperature,
oxygen content, water cleanliness and the material of the pond
bottom have an influence on the kind of life present. In any
pond it is essential that there is a balance of different
kinds of organisms so that there is enough food for them all
to live and reproduce.
More than 1,000 species of animals live in
ponds - although you are unlikely to find all of them in any
single pond. Almost every group of living creatures is
represented, except starfish which live only in the sea. In a
large pond you may find mammals such as water voles and
water shrews - and birds like ducks, herons and
Even the smallest pond
will have a population of amphibians
(frogs, toads and newts), small fish e.g.
sticklebacks, and a huge variety of invertebrates
(minibeasts). Some of these are herbivores such as water
fleas and snails, whereas others are aggressive
carnivores, hunting down their prey, the unfortunate
herbivores! One of the largest invertebrate predators in a
pond is the great diving beetle - no tadpole is safe
when one of these hunters is around!
Many different food
chains are to be found in a pond because each animal eats
As with any habitat, if
ponds are in danger of disappearing, then the wildlife in them
is also endangered.
PONDS PAST AND
For centuries, ponds were an essential part
of people's lives. The water was used by both humans and animals. As
technology advanced and water became available at the turn of
a tap, many ponds were neglected. Since most ponds were
man-made, when abandoned by man they were taken over by
nature; plants at the edges took over where there were no farm
animals to trample them down and some ponds ended up as marshy
bogs. Fallen leaves choked ponds and the oxygen vital for
pond-life, was used up as they decayed. Other ponds have been
destroyed by pollution or drained and filled in to make way
for buildings and farmlands.
Ponds of our countrysides
are now an ENDANGERED
The water in a pond
must remain clean if it is to provide a healthy environment
for the organisms (animals and plants) living in it. The natural
waste from the living and dead organisms is ‘recycled' by
special tiny organisms called bacteria.
Plenty of oxygen is needed for the bacteria to ‘break down'
the waste. The pond can take care of its own waste - it's
people who cause pollution!
The most noticeable kind of
pollution is the dumping of
rubbish - anything from old cars and cans to bikes and
bottles have been found cluttering up ponds. Such thoughtless
behaviour not only makes the environment look so unsightly but
it may also destroy pond-life.
Perhaps the most serious threat
to ponds is chemical
pollution as a result of modern farming methods. Over
the years fields have been sprayed with pesticides to rid the crops of
pests. However, rain often washes the excess chemicals off the
crops into nearby ponds, streams or rivers, poisoning some of
the animals living there. Fortunately, these poisonous
chemicals are not used so freely now and, hopefully, this
problem will gradually be reduced.
Another, equally serious, problem
connected with agriculture is the use of artificial fertilisers. Powdery
chemical fertilisers, containing nitrates, are put on the
crops to help their growth but they can also be washed off by
rain into nearby ponds. They do not poison the wildlife but
the rich supply of nitrogen causes the water plants,
especially algae, to grow
very quickly. The plants use up so much oxygen during the
night and when they decay that there is none left for the
other pond-life. The growth also prevents sunlight reaching
the organisms below. Eventually, all the algae die leaving a
stinking, decaying mass. The case of excess nitrates in water
is called eutrophication.
OF PONDS - HOW CAN YOU HELP?
We can all help ponds and their
wildlife in some way. Here are a few practical ideas:
Have a look
around your neighbourhood and see if you can find any ‘wild'
ponds. If you think a pond needs improvement e.g. rubbish or
plants removing, perhaps you and some friends or family could
try to renovate it. It is best to ask for advice and help on
pond management from professional organisations. By the way, ponds can be deep, so
take great care and never go alone! It's best to persuade an
adult to go with you and help.
Pond-dipping is a
lot of fun and a good way of finding out just what is living
in a pond. A wide variety of creatures would indicate that a
pond was healthy. However, always remember that the most
important thing is the safety of the animals. Return them to
the pond as soon as you have finished studying them. It is
fascinating to collect frog or toad spawn to watch it hatch
but return most of the tadpoles to the pond. If you keep a few
tadpoles to observe their development, look after them
carefully and return them to their pond when they have grown
These are obviously much
appreciated by animals such as frogs and dragonflies
whose countryside ponds are disappearing. A garden pond designed with
wildlife in mind is an exciting and worthwhile project to
undertake - and not difficult if you have someone to help
you. You will be surprised just how quickly animals
are attracted to the newly-filled pond. Other garden
residents will welcome the water for bathing and drinking. You
may have birds, hedgehogs, mice, foxes and bats making good use of your
pond. As well as providing a much needed home for wildlife,
you will enjoy watching your pond improve as time goes by. A
seasonal diary of pond events makes a good