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“When
biodiversity
brings my city
to life!”
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What is
biodiversity?
Document produced by Veolia Environnement
sheet 1
Biodiversity –
everyone is talking about it.
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But what is it?
Biodiversity is the whole range of life which surrounds us. Biodiversity… is life!
Look around your classroom, your village or simply in the street – how many different
people there are! There are no two people the same, even in your family. We all look
like our father, our mother, our brother or our sister, even our grandparents. But only
a little bit. We are each unique. We each have our own character, personality and
talents… even identical twins.
This diversity can also be seen between ethnic groups and peoples. Each one has its
own customs, its view of the world, its language and sometimes its own morphology.
The same is true in nature.
In the school yard, in a park or in the forest, listen to the songs and calls of the
animals. Identify their tracks (paws, claws, droppings, abandoned feathers, etc.).
Finally, look at the shapes of the plants. So much diversity…
But to be certain, you need to compare. Go to a park, a forest, an area of grassland, a
meadow, a simple copse, a farm, the side of a road or a river. How many types of plants
can you count in each of these places? Try to grade them: which environments appear
to you to be poor and which rich?
—
Keywords
Biotope: natural habitat of one
or more species.
Food chain: series of living
organisms which eat each other.
Ecosystem: a food web within
a biotope.
Species: collection of individuals
capable, through reproduction,
of producing fertile offspring
(capable of reproducing).
Ethnic group: group of humans
who share a common language
and culture.
Habitat: place where individuals
from one or more species live.
Individual: representative
of a species (plant, animal,
fungus… anything!)..
Morphology: shape, structure
and appearance.
Sexual reproduction:
production of a new generation
of individuals using the sex
organs. Sexual reproduction
enables the mixing of the male
and female genes.
Asexual reproduction:
reproduction without sex,
through budding, division,
etc. There is no mixing of genes
so the descendents are almost
clones of their genitors (almost,
since there are always some
errors in the transmission
of genes).
Int
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Biodiversity means both
the number and… the diversity.
It is landscapes, ecosystems, habitats, living environments and all that they
contain – species – and above all the relationships they have among themselves and with their environment. Within each species are individuals, which
are all different.
Specific diversity
Genetic diversity
Ecological diversity
The first thing you notice when you
observe your surroundings, “looking for”
biodiversity, is that it is everywhere.
There is a biodiversity of individuals, e.g.
your class or village. This biodiversity
comes from reproduction, which mixes the
genes of the mom and dad. Specialists call
this “genetic diversity”. There are more
similarities between two individuals from
the same family than between two individuals from different ethnic groups.
Then there is diversity of species. This is
called "specific diversity". Bacteria, plants,
animals, whales and earthworms, grass and
baobabs… Specialists have identified 1.8
million species, but have not agreed on a
total number. Probably between eight million and… 100 million! Why is this
important? If more species can be counted
in a forest than in a meadow, does it mean
the meadow is not as “rich”? Certainly not.
On another level, there is "ecological diversity”. This refers to various landscapes and
habitats. A region may have few species,
but many landscapes. This is true of France,
which specialists refer to as "megadiverse"
since it contains many very different landscapes in a small area. However, it has less
species than Alto Mayo, a very small region
of northern Peru…
There is also less diversity in relationships,
“interactions” between individuals in populations, between populations, between
species in their habitats, and between
species and their habitats. Everything is
linked. The living world is a giant tapestry,
in which each thread is a species, an individual or an ecosystem. When a thread
becomes loose, there is the threat that one
day the whole tapestry will disappear…
Biodiversity does not like standardization.
In a very small surface area, there can be
a very high level of biodiversity if there
are a lot of different habitats.
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There’s more
to life than
species!
Sexual reproduction –
a good thing for biodiversity!
A species which divides or buds produces descendants very
quickly and in very high numbers. But all its descendants are
identical! This is asexual reproduction. If a disease or parasite
arrives, the whole of this little world risks being affected.
With sexual reproduction, however, individuals from a single
species are all different. This means each will react differently to
the disease or parasite. Ultimately, sexual reproduction enhances
genetic diversity.
“There were so many species in the
past and there are fewer today.”
That is easy to understand. But it is
meaningless, since biodiversity is
about more than simply species. It is
much more complicated than that!
Species alone do not make biodiversity… What is important is the
network that species form with one
another.
Asexual reproduction
Sexual reproduction
Biodiversity is like a tapestry in which each thread
is a species. The more threads there are, and the
tighter they are, the better an attacked ecosystem
will be able to return to health.
“When
biodiversity
brings my city
to life!”
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Can cities
be part of
“nature”?
Document produced by Veolia Environnement
sheet 2
In search of
urban
biodiversity
—
Keywords
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Are cities enemies of nature because
they are artificial?
You only find what you look for. Look for nature around your town or city! Look for the
wild grasses, enormous trees, birds, mammal tracks and frogs’ calls!
Explore your neighborhood, village or town in a small group for a set amount of time (e.g.
two hours). Cross it from one side to the other, in a straight line, in any direction. This is
called a "transect". Mark any "places of nature" you find on a map. A copse, a garden, a
pond or just a crack in the wall – for each one, note down the different forms of life (flowers, trees, moss, butterflies, etc.) and, for each one, estimate how abundant they are
(using symbols, e.g. stars, from “not many” to “a lot”).
Then visit the suburbs or the countryside outside the town. Conduct the same experiment
– take a walk! Note down what you see and estimate the abundance. Mark these "places
of nature" on a map and describe in detail the environments you come across (field,
meadow, vineyard, cattle farm, etc.).
Back in the classroom, draw up a nature profile of your neighborhood, village or
town and decide which environment (city/town, suburb, village or countryside) is the
"richest”?
Intensive farming:
type of production involving
immense plots of land and
the massive use of pesticides,
fertilizer and agricultural
machinery.
Wildlife corridor: space
linking natural environments
to one another. A path, road,
tunnel or series of parks
and gardens could all be
corridors.
Fauna: all the animals
living in a single place.
Flora: all the plants in
a region.
Fragmentation: separation
of a biotope, habitat or
ecosystem, into several
fragments as a result of
urbanization and agriculture.
Wasteland: space without
a use, abandoned, taken
over by flora and fauna.
Pesticide: chemical product
used to combat any sort
of parasite (animal, plant,
fungus, etc.).
Chicago, United States
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It is surprising to discover
how much “wild” life there is
in cities.
By taking a closer look at towns and cities we can rediscover parks and gardens,
appreciate the height of buildings and street lamps, notice damage to walls and
roofs and cracks in the sidewalk...
Ljubljana, Slovenia
Yes, towns and cities are rich in fauna and
flora. You can find birds, reptiles, amphibians and mammals. How does this miracle
come about? Because the city provides a
whole range of habitats for plant and animal life. Cities contain holes, cracks, walls,
courtyards, embankments, gardens, flower
pots, parks and ponds… In other words a
range of soils, different levels of exposure to
the sun and varying levels of humidity. This is
of great benefit to “wild” life.
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Bombay, India
And water is also always available in towns
and cities, even though it may be lacking in
the surrounding countryside. And towns
and cities contain streets, sewers, canals,
railroads – all paths of communication for
fauna. These wildlife corridors allow animals to travel between their various
habitats which may be divided up by urbanization. Other corridors exist in the air: tall
buildings, lampposts and trees in parks are
also sanctuaries for birds!
It is no surprise that some towns and cities
can be richer than the countryside: sometimes they are surrounded by countryside
that is arid, polluted or fragmented by
roads and parking lots. This is an example
of the “refuge effect”: threatened or disturbed everywhere else, flora and fauna
can find relative peace in towns and cities.
For us, cities are artificial. For plant and
animal life, cities provide a wide range of
habitats.
Towns and cities are full of food –
our waste! This attracts many animals
and some end up not being able to live
without humans.
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The city is
a good mother
In the city there is always shade even when it is very
hot. When it is cold, there is always a source of heat
(heating, subway, traffic, etc.). The city is a haven for
plant and animal life.
The protective city
The city provides a whole range of habitats for
plant and animal life: gardens, embankments,
flower pots, etc. It provides animals with
communication channels: sewers, railroads,
canals, etc. This helps them get around!
Plant life can grow in the smallest patch of bare soil. A crack, a hole,
the edge of the road or a huge abandoned plot, these “wastelands”
are an opportunity for biodiversity.
They should be left to live, without pesticides, and only occasionally
cleared.
“When
biodiversity
brings my city
to life!”
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Nature in cities,
but where?
Document produced by Veolia Environnement
sheet 3
But why is there
so much life in cities?
In one place there are flowers, butterflies
and mammal tracks, but not in another.
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Why?
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[Same activity as sheet 2, but in a different way]
Explore a neighborhood for a set amount of time…
Each group sets out to look for "stations" — places where flora and fauna are to be found. Firstly
these need to be marked on a map, then described as accurately as possible: what is the surface area (small, medium, large, very large), what is the soil like (earth, stone, pebbles, rubble, a
wall, etc.), is the station in shade or well lit (by the sun or a street lamp?), is there water, humidity, or is the station “dry”, what sound is there… "type" (edge of the road or river, a garden, a
square…), is it looked after or abandoned?
Don’t forget to note down an important piece of information on your sheets: is the station
affected by human life? (Is there noise, pollution, waste? Do a lot of people pass it, trample over
it, etc.?)
Once each station has been fully described, try to assess the variety of species. Do you think it
is low, medium or high?
All the groups compare notes to identify anything which the richest and poorest stations have
in common. What seems to encourage or discourage biodiversity in towns and cities?
Finally, the groups meet up and share their observations. All the stations, with their level of richness and surface area, are plotted on a map. Is the richness or poverty of the stations localized?
Is the richness linked to stations’ surface area?
—
Keywords
Archipelago: chain
of islands.
Noise: this disturbs many
animals, which therefore
avoid it.
Trampling: repeated
crushing of plants which
leads to a decline in plant
biodiversity, in favor of a
few very ground-hugging
and hardy species.
Residential
neighborhood: quiet
neighborhood made up
of houses or low
apartment buildings.
Surface area/species
ratio: the larger the
surface area of a natural
environment, the higher
the number of species
found there.
This rule applies
particularly to isolated
environments, such as
islands and city parks.
Street lamps: artificial
light disturbs many
species, e.g. birds,
because it prevents them
from properly sensing
the change from day
to night.
Int
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Cities are a sanctuary
for flora and fauna –
a real archipelago.
Gardens, squares and parks are islands which form an enormous and varied
surface area if they are connected by corridors.
Paris, France
The places in the town or city where biodiversity is strongest are naturally parks
and gardens. Why?
Because they contain different sorts of
environments: copses, hedges, shrubs,
trees of various heights, areas of water,
ponds and rivers. Because they are generally large. And yet the larger the space, the
more chance flora and fauna will have of
finding habitats which suit them. In principle, the diversity of species in city parks
and public gardens is therefore high.
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Chicago, United States
In practice these parks and gardens sometimes do not have a high level of ecological
diversity, since the habitats they offer are
all similar. This happens if gardeners have
only planted a single type of tree and grass,
for example. This very small number of
habitats will encourage a very small number of species.
Scientists think that parks, squares and
gardens are like islands. An island’s flora
and fauna is isolated from other islands by
the streets and buildings. But there is a
solution! Rows of trees, river banks, tunnels
and hedges help flora and fauna travel from
one green space to another. They become
wildlife corridors and can be compared to
bridges linking islands to one another.
Thanks to these wildlife corridors, the total
surface area of green spaces in towns and
cities can be considerable. That explains
why residential neighborhoods are often
“greener” than city centers: they contain a
lot more varied gardens, hedges and trees
close to one another.
Fauna does not like being disturbed and flora
does not like being trampled. Biodiversity
moves into quieter areas of towns and cities
to escape the noisy, overcrowded areas.
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The biotope of skyscrapers
Pollution?
Not for
everyone!
At first glance, polluted areas do
not appear particularly favorable
to biodiversity. However, if humans
do not clean them up, they are colonized by strange plants which do not
mind pollution. These plants gradually absorb the pollutants in the soil as
they grow.
United Kingdom
In city centers, skyscrapers and religious buildings are often a
haven for birds which, in the wild, like cliffs and tall trees. They
are also home to birds of prey which feed on the fauna in parks
and gardens…
There are a lot of birds in towns and cities, thanks to tree-lined
avenues. Unfortunately if the same species of tree is always
planted, the habitats available to birds will always be identical.
Habitats, and therefore plantings, need to be diversified for
there to be many different animal species in a town or city.
“When
biodiversity
brings my city
to life!”
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They are
invasive!
Document produced by Veolia Environnement
sheet 4
Colonized
cities?
Cities can favor biodiversity.
Some species have taken advantage of
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invaded it and can cause damage.
Cities are a refuge and have a high level of biodiversity. However… have you noticed
how some species are a lot more common than others?
Let’s take the example of birds. In a city park, look for a long time at the top of the highest buildings or a large area of water. Take the time to let your eyes adjust. Then note
down on a sheet of paper the “types” of birds you see the most often. It doesn’t matter if you do not know the name of a species! Just note the “type” — a shape, a way of
flying, or the particular formation of a flock of birds. The aim of the exercise is to identify the types which are there all the time, i.e. those which are more numerous than
others.
You can do the same with butterflies, by assigning yourself a “post” in a meadow or
flowered garden.
The same exercise can be carried out for plants. In a park or a public garden, then in
an area where vegetation grows “spontaneously” (without having been planted, e.g. in
the street or on wasteland). Finally, in a neighborhood with a lot of private gardens, ask
yourself this question: are there “types” which are also there all the time?
—
Keywords
Anthropized: influenced,
controlled, modified or
managed by humans.
Commensalism:
a relationship between
organisms in which one
benefits from the other
without harming it too
much – humans and species
in cities, for example.
Invasive: a species, breed
or variety which directly or
indirectly harms humans.
Resting place: tree or pond
on which flocks of birds sit
to exchange information.
Int
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The living conditions
offered by cities are often so
favorable that some species find
it hard to live without them.
Some have grown in number so much that they have become a serious nuisance.
Biodiversity is especially strong in
towns and cities because “green” spaces
(woods, gardens, planted land, wasteland,
etc.) are large and linked to each other.
However, one thing is noticeable in even a
very green town or city: the same species
are always seen. There are few of these
species, but their numbers are very high.
Let’s take the example of a city and a natural ecosystem. In cities, you often notice
that some species have very high numbers
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compared to others. In the natural ecosystem, species’ numbers are often similar to
each other. This permanent unbalance is
how you can recognize an artificial or
anthropized ecosystem, i.e. one influenced
by humans.
As a result of this “refuge effect” in towns
and cities, some species reproduce better
and faster than in the wild. Their way of life
has been modified so that they can make
the most of the “benefits” offered by
humans. And some species have become…
urban. Why is this? Because it is difficult for
these species to live without humans. They
are commensal… on humans. They are the
ones you see the most because their numbers are huge: pigeons in European and
American towns and cities, or rats, cockroaches and termites all around the world.
Humans sometimes find these species a
nuisance!
What can be done to avoid invasion by certain
animals? Firstly, we must avoid feeding them.
Urban fauna takes advantage of the abundance
of food. Make sure trash cans are properly
closed!
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Too many
Imported plants
Gardeners often plant the same varieties of plants because they
grow quickly, require little maintenance and are cheap. These
plants then re-seed themselves and become… invasive.
birds?
Clip your
hedges…
Some birds live in enormous
flocks. They need resting places,
trees or shrubs to meet up and
exchange information. So if there
are really too many, prune some of
those trees and shrubs!
The droppings of town and city animals
are a source of dirt and degradation.
They can contain infectious parasites
and need to be cleaned up.
“When
biodiversity
brings my city
to life!”
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Let’s encourage
biodiversity in cities!
Document produced by Veolia Environnement
sheet 5
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Why are some
neighborhoods
"greener"
than others?
Explore the architecture and
urban planning of green neighborhoods…
Keywords
Architecture: the art of
designing plans of buildings
and then constructing them.
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Based on the other sheets and the work already done, make suggestions to explain
why some places are “greener” than others.
Here are a few little gardening jobs to help you.
Find a part of the school where there is nothing: no plants and no insects. How can you
change that? Make suggestions! You will need flowers, so sow some in pots, bags or
anything else suitable. You can also add plants and shrubs you find in the wild (don’t
take too many), in your gardens or bought from a store. Arrange them however you
want – on the ground, on chairs, etc. Also place containers of water between the pots.
If the “poor” part of the school happens to be earth, dig it over. Then sow an assortment of seeds, and plant other plants and shrubs in the ground. Create small ponds and
place pebbles and stones in them.
Have fun! Try whatever you want!
The main thing is that the plants grow and that the insects and birds come. If you think
there are not enough insects and birds, start the experiment again. Make suggestions
to improve the biodiversity in your school… then in your town or city!
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Residential block: group
of houses organized around
a courtyard, garden or a park.
Organic matter:
matter containing carbon
which is produced by living
things: plants, animals
and micro-organisms.
Soil microfauna: fauna
in the soil invisible to the
naked eye.
Monotypic: habitats
comprising a single species.
Green wall or roof: wall or
roof covered in a surface on
which plants can grow. It is a
construction technique also
used to insulate buildings
from the outside.
Urban planning: the art of
designing and constructing
towns and cities.
Urban planners are a bit like
architects, but instead of
designing buildings, they
design towns or areas of
a town or city.
Int
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Even modern, dense, noisy,
polluted cities can prove very
favorable to biodiversity.
By agreeing to “lose” a little space, green islands can be created, connected by
corridors. Life is even possible in city centers!
Puteaux, France
It is obvious when you walk through the
streets that biodiversity can be found
anywhere there is vegetation! So the only
thing you need to do to increase biodiversity in towns and cities is make them greener:
plant or give nature a chance to “selfplant”.
But how can this be done in very “tightly
packed” cities, where land is scarce and
therefore very valuable? How can this be
done in cities surrounded by a great expanse
of suburbs which divide the natural environment up into lots of fragments?
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In cities, in a very concentrated habitat, we
can agree to lose a little “useful” space to
help nature: planting the courtyards of apartment buildings, climbing plants up walls,
laying out flower borders, creating “green”
balconies and even roofs. But be careful of
always planting the same thing, either to
make it easier, because it is fashionable or to
keep costs down. Biodiversity not only
means green, but several shades of green!
Nature also benefits hugely from wasteland.
Often an area of grass which has never
been mowed is enough to attract insects,
birds and small mammals!
City gardeners can put the same idea into
practice in parks and gardens. They can
leave a small area fallow, digging or mowing
as late as possible. They can leave dead
leaves to rot on the lawn or the earth. These
provide a home to microfauna and enhance
the soil with organic matter.
“Green” urban planning favors small
islands of biodiversity (parks, gardens, vegetable plots) and corridors connecting
them (tree-lined avenues, river banks, etc.).
Towns and cities must agree to leave some space for
vegetation. This space need not necessarily be used
to create city parks – planting a little everywhere
can achieve a lot!
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Vertical nature
Architecture can also favor biodiversity. Climbing plants,
balconies with trees, “green roofs” and even “green walls”?
Housing
estates
in blocks
There is something even better than
back-to-back houses: the ideal is
small apartment blocks of different
sizes with patios and balconies – real
little “islands” around parks.
Chicago, United States
Puteaux, France
By encouraging biodiversity in town and cities, we
attract birds. But these can hurt themselves on
windows, which they can’t see. To help them avoid
these, silhouettes of birds of prey can be stuck to
the glass!
“When
biodiversity
brings my city
to life!”
6
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Biodiversity?
Vegetable plots!
Document produced by Veolia Environnement
sheet 6
Is my vegetable
plot part of biodiversity?
Growing vegetables and fruit is not
very difficult. You just need to know
a few “tricks” which city-dwellers
have often forgotten.
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Together, collect some vegetable seeds and plants.
As many as possible – you'll need a lot!
Split yourself into two groups. One group will sow seeds and put the plants into several pots –
as large as possible. The other group will sow and plant in the ground. Where? If possible in the
soil in the school yard, which will need to be dug over. You can also create a plot in an authorized area, bordered by four planks which you fill with earth (up to 30cm high).
The first group, with the pots, will grow half of them in the classroom and the other half outdoors (try to have several examples of the same plants in each half if possible). The group will
arrange them in all possible combinations: side by side, at various intervals, horizontally, vertically, at an angle, etc. The first group will also try all possible living conditions: in the shade,
in the light, in a dry and a humid atmosphere, in the heat and in the cold, etc. How do plants
grow? What are the ideal conditions?
The second group will discover the joys of the vegetable plot. Can it manage on its own? Why
not ask advice from adults who have their own vegetable plots.
Students from both groups will come together regularly to discuss their difficulties and their
observations. Together they will discover flowering and pollination. They will organize a gathering for all the students’ parents to celebrate the first harvest…
—
Keywords
City-dweller: someone
who lives in a city.
Organic waste: dead
plant or animal matter.
Parasite: organism which
lives off particular crops
in the vegetable plot.
Proper maintenance and
watering make it possible
to control some of them.
Seedling: a plant at the
start of its growth, which
will later be transplanted
(replanted).
Herbs: plant with a strong
flavor used in cooking.
Herbs store up pollutants
from the air.
Vegetable plot: special
sort of garden for growing
fruit and vegetables.
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There are many advantages to
vegetable plots in towns and cities. They are
economical, attractive, social and environmental.
They need watering of course…
Vegetable plots have the advantage of
increasing the town or city’s green space.
There is also another advantage – they
provide us with something to eat! Yes, eat,
because a vegetable plot means food as
well as plants! Fresh food which those who
eat it, who want to know where their food
comes from, can have confidence in.
But where can you plant vegetables, shrubs
and fruit trees? Almost anywhere. In any
container high enough and with a hole at
the bottom (so the water can escape). You
can grow a plant in almost any position
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(including in a vertical support, such as a
trellis). The main thing is that the plants
have light and, most importantly, water –
that is vital. When the weather is hot,
plants need to be given a lot of water. One
way of watering them is to collect rainwater…
Owners of gardens can mark out a vegetable plot. All you need is enough space.
Towns and cities can also allow green
spaces or wasteland to be transformed into
communal vegetable plots. As well as the
food they provide, communal gardens
encourage contact between inhabitants.
Growing fruit and vegetables in towns and
cities is also a way of preserving agricultural knowledge which is being lost. And by
encouraging city-dwelling gardeners to
grow rare varieties, society makes them
curators of agricultural biodiversity!
Finally, vegetable plots are relaxing for
city-dwellers. Working the soil, seeing what
you have sown grow and harvesting after
months of waiting all help reduce stress.
You can grow fruit and vegetables at home.
If there is not much room, they can also be
grown in a window box on a balcony!
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Vegetable
plots mean recycling!
A vegetable plot is also a way of recycling organic
waste if you fertilize it with compost. It is also an
effective way of filtering the air of its pollution. But
make sure you wash the fruit and vegetables before
eating them!
Tomatoes
Companion planting
for a less chemical
vegetable plot
If correctly combined, some varieties of vegetables
and flowers protect each other from their respective
parasites. It is therefore not always necessary to use
chemicals to protect your vegetable plot. Here are some
examples:
Basil
Radishes
French marigolds
Lettuces
Chives
Carrots
Beans
Rosemary
Sweetcorn
Beans
Sunflowers
Cabbages Thyme
Celery
Potatoes
Keeping bees in the city? Why not! Bees sometimes find more
flowers to gather pollen from in towns and cities than in the
surrounding countryside. The honey they produce has more flavor
and sometimes also contains less pollutants. And establishing
beehives in towns and cities also means protecting bees, which
are on the decline all around the world.
“When
biodiversity
brings my city
to life!”
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Biodiversity and
our waste?
Document produced by Veolia Environnement
sheet 7
Garbage-collecting
animals and
recycling worms
We can cut down on waste by turning
one
o be d
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Activ with your
it into fertilizer. Give it a try!
tes
assma
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Compost can be used to make natural fertilizer.
How? It’s very simple.
You need quite a large plastic container 1 20cm to 30cm high. Pierce about 10 holes
5mm to 8mm wide at the bottom. Then, about 5cm high, spread out a mixture made up
of organic waste (not grass), very fine soil, paper and shredded card.
Sprinkle water over the top… then drop some earthworms into the mixture. What type? Ones
that live in the soil where you live. You can find them by digging the ground. How many? A
2
maximum of 500g for 10cm (be careful, the bin will be heavy when you’ve filled it up!).
After you’ve added the worms to the mixture, cover with a thin layer of kitchen waste
(no acidic products like citrus fruit, onions or leeks).
It’s almost finished. All you need to do now is place two other identical containers
2
3 on top of this one. Fill them every day with organic waste, paper and card… As
soon as the worms have digested the contents of the first container, they will move onto
the second, and so on.
Don't forget to put a cover over the highest container as worms don’t like the light.
Also remember to place another container under the first, pierced with a single large
hole 4 . After a few weeks a juice, the “tea”, will run out of this hole. And all that will
be left in the first container is a very fine soil, the compost.
Tea and compost – you have just made two very effective natural fertilizers!
3
2
1
4
—
Keywords
Compost: mixture of earth
and the product of the
natural decomposition
of organic matter.
Waste: what is thrown into
the trash can.
Organic waste: dead plant
or animal matter.
Fertilizer: product added to
soil to help plants become
big. Compost is a natural
fertilizer.
Organic matter:
matter containing carbon
which is produced by living
things: plants, animals and
micro-organisms.
Methanization:
transformation of organic
waste into compost and
methane. This process occurs
in a “reactor” sealed off
from oxygen and light.
Phytoremediation: removal
of pollution from the soil by
plants.
Tea: the “juice” which runs
out of a composter after
a few weeks.
Int
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Nature has the ability to recycle.
Biodiversity transforms part of the waste
it produces.
1
Composting is a system which reveals biodiversity’s role as a recycler. This is what
happens in nature, as well as in parks and
gardens: fauna and micro-organisms in the
soil (worms, insects, mites, bacteria, ants,
fungus, etc.) eat abandoned organic matter
(dead leaves, pine needles, etc.) 1 . They
transform them into a sort of very fine soil
(compost) 2 and a dark liquid (the “tea” in
the experiment). This solid and this liquid
contain nutritious matter which feeds
plants. In this way, biodiversity maintains
2
itself by recycling its dead organic matter
into fertilizer. This natural fertilizer will
ensure that the soil is good quality. New
plants and trees will be able to grow 3 .
Composting also has a symbolic value,
since it shows that waste nourishes fauna
in towns and cities.
One major reason there are so many animals
in towns and cities is because there is so
much waste: abundant food all year round,
without the need to hunt it. This is a blessing
to animals!
3
It is a hazard to humans, however. Animal
droppings are a source of dirt, which is harmful to health and hygiene.
Flora can also be of service to humans. When
the soil is polluted, specific vegetation
always develops. By clearing it regularly, the
pollution is cleaned from the soil since these
plants concentrate it in their tissue…
Plants can therefore help clean up a polluted
area. After a few years, the site can even
become a garden or a park! This is called
phytoremediation.
Towns and cities nourish their
st
biodiversity. But 21 -century humans
produce a lot of waste.
It is very important for us to give
nature a helping hand, through the
sorting, disposal and treatment, as well
as recycling, of waste.
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Waste can also be used
to produce energy!
They take
advantage
of our waste
Waste that builds up in the street
attracts animals. That causes damage
which is harmful to health and hygiene.
And it’s also not very pretty! Waste
should be placed in garbage containers.
Make sure the lids are properly closed!
Grass clippings and kitchen waste placed in sealed tanks is transformed into compost by bacteria, as well as into methane. This
gas can be used directly for cooking or to turn turbines to generate electricity.
Humans produce a lot of waste. Biodiversity is naturally
capable of recycling a small proportion of it… Humans must
obviously lend a hand – by sorting and recycling their waste
they can give it a second life! This also benefits nature
since recycling waste means using fewer natural resources.
“When
biodiversity
brings my city
to life!”
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Biodiversity,
going with the flow!
Document produced by Veolia Environnement
sheet 8
How can
biodiversity
reduce flooding?
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mates
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Nature controls our water
supply.
How? In particular using plants.
Experiment 1 /
Take a rectangular container 20cm high. Fill it to the top with earth, without tamping it down. Then support it, so that it is tilting, above a sink. All
set? Now slowly pour the contents of a watering can over the container.
Repeat the process until the water overflows. How long (or how many
watering cans!) did it take?
Repeat the experiment, but this time tamp down the earth. Now let the
container dry and, when the earth is really hard, repeat the experiment
again. Which earth (not tamped down, tamped down and wet, or tamped
down and dry) did the water overflow from the quickest?
Experiment 2 /
Now fill up a container of earth and plant a lawn in it. Pour over the contents of the watering can when the lawn is short. Time how long it takes
for the water to overflow. Then leave the grass to grow until it is high, and
pour over the contents of the watering can again. In another container,
plant wild grass or put in a square of wild grass or flowers you have dug
up. Again, time how long it takes for the water to overflow…
Can you now grade the containers of earth used?
—
Keywords
Agglomeration: collection of towns linked
to each other.
Upstream: above, part of a river
located before a city, for example.
Downstream: below, part of a river located
after a city, for example.
Compacted: soil which is so tamped down
it is impermeable.
Impermeable: waterproof, does not
let water or gas pass through.
Lawn: fine grass cut regularly so that it
remains short. A lawn contains very few
species.
Humidity: presence of water or water
vapor in the air.
Soil microfauna: fauna in the soil invisible
to the naked eye.
Grassland: natural surface covered in a
large number of plant species, which can be
mown twice a year (particularly to feed
cattle).
Soil: fertile part of earth.
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Living soil
is essential to reduce flooding
and naturally clean water.
In the experiment, water flowed faster over
the surface of the bare soil soil than the
planted soil. It is even faster over the surface of tamped down, dry soil! Why?
Because when rainwater falls, the soil
“drinks” it.
In fact, the water fills the spaces between the
grains which make up the earth. When all
these spaces are filled (e.g. when the earth is
tamped down), the earth can no longer
absorb anything and water which then falls
on it is forced to flow over its surface – it is
said to “run off”. This can cause flooding.
There are no empty spaces in bare earth
compacted (tamped down) by farming
machinery, dryness or frost, and water
streams almost as quickly as over the surface of a road. Exactly the opposite effect
occurs on grassland – which retains the
water for a long time because it has a lot of
roots and a high level of microfauna – due to
the fact that there are a lot of spaces in the
earth.
Vegetation is therefore very beneficial to us.
It provides natural protection against flooding.
What happens in towns and cities? An
agglomeration is largely impermeable as it
contains a lot of road surfaces. This stops
water infiltrating it. When it rains heavily in a
short space of time, the drains overflow,
rivers downstream fill up and this leads to
flooding.
Unfortunately large areas planted with lawn
or cereal crops do not absorb a lot of rainwater, especially if they are not surrounded by
hedges or trees to hold some of the run-off
water.
Noortalje, Sweden
L
Wetlands (marsh, ponds, wet grassland, etc.)
disperse floodwater as well as providing water
storage, even in summer. It is really very important
to make towns and cities greener upstream!
§
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More worms,
less flooding!
Meadows hold water and remove pollution, since
there are so many roots and so much fauna, including
earthworms.
By drilling through the soil, roots and earthworms
aerate it and increase its ability to absorb water.
Nature plays
a crucial role
upstream of cities
Wetlands help to clean the quality of the water. In a
pond, water can be filtered by aquatic plants and microorganisms. Wetlands also often have a very high level of
biodiversity!
Wetlands help to clean the quality of the
water. In a pond, water can be filtered
by aquatic plants and micro-organisms.
“When
biodiversity
brings my city
to life!”
9
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Biodiversity
cools cities
Document produced by Veolia Environnement
sheet 9
It feels better
in
the shade and the breeze!
It is good to plant trees and hedges and to
create parks and gardens, which increase
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Activ with your
biodiversity in cities!
mates
class
It makes it easier to breathe.
In this experiment you will record the temperature you feel (are you slightly hot, hot or
very hot?), and the temperature shown on the thermometer (make sure you place it at
head height, if possible to the north if you live in the northern hemisphere, if possible to
the south if you live in the southern hemisphere! The most important thing is that the sun
does not shine directly onto the thermometer).
Stand right in the sun. What do you feel? Firstly with a bare head? Then with a hat on? Then
under a parasol or an umbrella? Then with an electric or hand fan? In which situation do you
feel most comfortable? When you feel most comfortable, has the temperature really fallen?
Now stand under a tree in the town or city. Again, record the temperature you feel and the
temperature on the thermometer. Do the same next to a variety of water sources – a river, a
fountain, a pond, a water fall or a jet of water.
When you get back to school, stand in front of a fan. Set it to medium power and throw flour
in front of it. This time repeat the experiment, placing a few plants fairly high up between
you and the fan…
Finally, take a plant and place it in the shade. Entirely cover it in something transparent. What
do you observe? (When it wilts, uncover it and water it!).
—
Keywords
Heat island: accumulation
of hot air above cities.
Evapotranspiration:
accumulation of evaporation
from the land and plant
transpiration. This water
evaporates into the
atmosphere due to the
effect of heat.
Particle filter: device
placed on a chimney or
beneath a chimney pot.
It traps some fine particles
and reduces pollution.
Real temperature:
temperature displayed
by a thermometer. This is
measured in the shade.
Comfort level: perceived
hot or cold.
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Vegetation is an excellent
insulator. It is also a very effective
particle filter and air dehumidifier.
It is important to incorporate
it all around the city.
The big problem with modern cities is the
heat. They concentrate heat, firstly
because they are covered in asphalt.
During the day this road surface absorbs
heat, some of which it releases into the air
at night. This means summer nights are
never cool in big cities! Secondly, in big
cities there are a lot of vehicles which give
off a lot of heat. Unfortunately very little of
the energy contained in gasoline is transformed into movement – most of the energy
is lost in the form of heat!
This heat has trouble escaping. Wide
avenues and straight streets bordered by
skyscrapers capture it. The same phenomenon can be seen in the courtyards of
apartment blocks. All this accumulated
heat creates a sort of bubble above cities,
from which air and pollutants cannot
escape quickly.
However, it feels better in older cities even
when it is very hot. Why? Because their
streets are in shade, because the houses’
thick walls keep the heat out and because
there is… water and vegetation.
In general, trees, shrubs and vegetation benefit us enormously.
Firstly, trees create shade and increase the
movement of the air. Climbing plants insulate walls from the sun’s rays during the
summer and retain some heat during the
winter. This means that green walls provide
good insulation for homes. Vegetation also
has a third advantage: trees and shrubs are
able to retain certain pollutants and particles suspended in the air. They are
therefore very effective filters against pollution. Finally, don’t forget that vegetation
also loses water when it transpires, in a
process called transpiration. When it is hot,
plants and the soil release water into the
atmosphere, in the form of water vapor.
This phenomenon explains the coolness
and humidity you feel when you walk in a
forest. The same cool sensation can be felt
by a pond, a river or close to a waterfall or
a fountain.
Shade, wind, water and plants allow
cities to suffer less when the weather
is very hot.
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Natural
insulation
Vegetation is useful even when the
weather is not hot. By acting as a
screen against the wind and the air,
trees, shrubs and climbing plants help
to insulate walls.
Vegetation and water –
two heat pumps
Plants lose water through transpiration. Aquatic areas and soils
lose it through evaporation.
The combined effect, known as
evapotranspiration, is a physical
process which consumes energy.
By transpiring, a plant takes heat
from the atmosphere. So it cools
it – a little! In exchange, it gives
it its water, the humidity which
will later be transformed into…
rain!
Urban forests have a well-known role
in combating pollution – they filter
particles and some pollutants released
by exhaust pipes.
“When
biodiversity
brings my city
to life!”
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Zoos and museums,
guardians of biodiversity
Document produced by Veolia Environnement
sheet 10
Why visit
the zoo?
Zoos are an ideal place to take a walk in cities.
They are also somewhere to learn about the
animal kingdom. Museums, meanwhile,
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offer an insight into the state
Acti with you
mates
class
of biodiversity.
What is the purpose of zoos, zoological parks and menageries?
Visit one. What species can you see there? Are they local (do they come from near you)?
Make a list and, next to each species, note down where it comes from (which continent
is enough). Then go and ask the managers or carers where the animals on display have
come from. Also ask them about any births at the zoo. If there have been any, what do
the newborns do?
Then look at how the animals are cared for. Look at the coats and the feathers. Do you
think the cages and enclosures are big enough, well maintained and decorated? Do the
animals appear to be lively or tired?
Then visit a natural history museum or, in a general museum, its section dedicated to
animals. Are there many local species? As far as possible, for each local species, try to
identify its “status” now (the species is not endangered, it is endangered, or is vulnerable or threatened, or even… extinct). Has species’ survival changed over time? Identify
all the museum’s extinct species and try to rank them by the century in which they
became extinct.
—
Keywords
City-dweller: someone who
lives in a city.
Menagerie: a very small zoo.
Museum: museum dedicated
to the natural sciences
and the study of life.
Mounted: stuffed.
Zoological park: a very
big zoo.
Reintroduction of a species:
release of animals born in
captivity (e.g. in zoos) into
their natural habitat.
Zoo: place where you can
go to see animals.
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Zoos, menageries and zoological
parks now play a very important role
in the conservation and safeguarding
of rare species. And museums’ collections
enable researchers to identify changes
in biodiversity.
Zoos, zoological parks and menageries
are vital attractions for city-dwellers.
Why? Firstly, to provide family days out.
Going to the zoo is one of the leading
leisure activities for families all around the
world. It provides a chance to “rediscover
nature”: seeing it and experiencing it is
vital to our well-being. Even in a cage, biodiversity offers a little fantasy and
relaxation. We all go to the zoo, because
that is where we can see animal life under
the best conditions (it is easier to look at a
tiger and a vulture in an enclosure than a
mammal or a bird that live in a city park!).
Finally, for many of us, biodiversity above
all means the biodiversity of our imagina-
tion. An elephant, for example, attracts
more attention than a red kite.
In the last 20 years, zoos, menageries and
zoological parks have played an essential
role in the preservation of endangered
species. Representatives of each species
live in large, decorated areas, designed to
be reminiscent in some way of their original
natural habitats. Animals now breed in zoos,
since that is where they live. Zoo animals
are therefore no longer captured in the
wild: they are born in zoos. When there are
too many animals in a zoo, individuals are
exchanged for other animals with another
zoo. When they have reached their adult
age, newborns of rare or endangered
species are sometimes reintroduced into
their original habitat.
And museums and galleries of mounted
animals give us an understanding of the
fragility of species. It is upsetting to see
species which no longer exist. And it is disturbing to see species which are still alive,
but perhaps not for much longer. Museums
are often also centers for research into
biodiversity. Mounted examples make it
possible to name and classify new species
without the risk of error. This gives us an
idea of the evolution of species’ biodiversity over time.
Zoos are a magnifying glass for looking
at biodiversity and help us to understand
it. Museums preserve a memory of the past –
they make it possible to assess biodiversity.
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The bond between
Museums are also
research centers
Natural history museums are dedicated to knowledge, conservation of biodiversity and the relationship between humans and
nature. They are also research centers.
humans and nature
In zoos, biodiversity is often more
about heritage than the local area.
The species that live there are part of
our collective imagination. They keep
alive in us the bond that still links our
species with nature.
Museums enable us to learn about species as they
were described by scientists the moment they were
discovered. By comparing these descriptions with
current data, we can gain an idea of their evolution
and their demography.
September 2010 / Document produced by Veolia Environnement’s Communications Department. Editorial coordination: Julie Chavaribeyre / Copywriting: Frédéric Denhez /
Illustrations (design and production): SLR / Illustrations: Laure Duquesne, Gilles Hureau / Graphic design: Valérie Charlanne, Téo Löhrer - Damien Lagier | COMAMA. Translation and layout: TagLine.