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learning about biodiversity Ecosystems

CAPS

In January 2012, a single comprehensive

Curriculum and Assessment Policy Statement

(CAPS) was put in place for each subject. As this

section of Veld & Flora is specifically targeting

the Further Education and Training (FET) phase

that incorporates grades 10 to 12, we will be

highlighting sections in which Veld & Flora can

be used as a resource to complement the FET

curriculum. The whole FET CAPS can be downloaded

from http://www.education.gov.za/Curriculum/

C u r r i c u l u m A s s e s s m e n t P o l i c y S t a t e m e n t s /

CAPSFETPhase/tabid/420/Default.aspx.

Be informed

Veld & Flora updates teachers and learners on what

is happening in the world of science, especially

in Life Sciences and Geography. Even if an article

is not directly about teaching the curriculum,

it will widen your and your classs general

knowledge, and give you a step up the academicladder. Download this fact sheet and the poster

overleaf on the BotSoc website http://www.

botanicalsociety.org.za.

Shapes and sizes

In the table opposite there are excerpts from the

Life Sciences curriculum for Grade 11. The poster

overleaf will assist in the teaching of ecosystems

as it demonstrates how our indigenous trees have

Living together

The flagship article on p. 56 of this issue of Veld & Flora,

Sunburst: Colourful associations between sunbirds and

flowers at Kirstenbosch by Johan Booyens, illustrates

perfectly the concepts of mutualism and urban ecology.

Kirstenbosch National Botanical Garden is b no means

And tis my faith that every ower enjoys

the air it breathes. William Wordsworth

An excerpt from the new Life Sciences curriculum for Grade 11

STRAND: Environmental Studies

Organisms interact with other organisms and with the environments in which they live.

TOPIC: Population Ecology

CONTENT

Interactions in the Environment

Predation

Competition - interspecific (for light, space, water, shelter, food).

- intraspecific (for food, access to mates, water, space, shelter).

Specialisation - Competitive exclusion and resource partitioning: One example of

coexistence in animals, one example in plants.

Parasitism - (Organisms that obtain food and shelter from another living organismat the expense of the other.) Two examples from Southern Africa.

Mutualism - (A form of symbiosis in which two organisms exist in a close

relationship of mutual benefit.) Two examples from South Africa: both

species benefit.

Commensalism- (An association between two organisms in which one benefits and

the other derives neither benefit nor harm.) Two examples from

South Africa: one species benefits.

Social organisation (mention only): Benefits of herds/flocks (avoidance); packs

(hunting) dominance; division of tasks (castes).

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as it demonstrates how our indigenous trees haveKirstenbosch National Botanical Garden is by no means

In South Africa, one region, very rich in plant

species, is characterized by the fact that many of the

shrubs and small trees present do not coppice. In

fact a characteristic of this biome, the Fynbos Biome,

is that many of the woody plants are obligative re-

seedersafter they are kill ed by fire. This means that

they only survive by producing seeds and cannot

coppice or re-sprout. This is the reverse of our

savanna and forest biomes.

Re-sprouters also have seeds, but young plants are

rare as survival is mostly by re-sprouting. So whereas

95-100% of the shrubs in grasslands and savannas

(and forests) are re-sprouters, only about 30% of

fynbos species are re-sprouters, the rest (about 70%)

being obligate re-seeders.

The Breede River Yellowwood (Podocarpus elongatus),

above, is one of our four species of yellowwood and the only one with the capacity to coppice or

re-sprout. A Western Cape endemic, it prefers to grow along rivers i n fynbos where it is subject to

episodic flooding. When the trees are knocked down in floods, the ability to re-grow ensures its

place on the river bank.

In the savannna and

bushveld it seems that alltrees are capable of coppicing.

Examples range from the

largest of trees like the

African Baobab (Adansonia

digitata), and Ebony Jackal-

berry (Diospyros mespiliformis)

to the smaller thorn trees

(Acacia), bushwillows

(Combretum) and Buffalo-

thorn Jujube (Ziziphus mucronata), all of which coppice

prodigiously. Of course all the shrubs coppice too. The

Red Bushwillow (Combretum apiculatum) shown left is

a vigourous re-sprouter, which is of great advantage

in times of drought. Elephants partially knock the trees

down and chew the roots to get water. The trees are also subjected to fires and are able to survive

thanks to their coppice growth. In fact the whole tree architecture, with its characteristic wand-like

branches, is totally adapted to survive such damage. Elephants

love the African Marula (Sclerocarya birrea) and break off branches

to eat the leaves and fruits, tearing off huge chunks of bark and

toppling trees to get water from the roots. As a result the trees

ability to coppice is a good survival strategy, as you can see on the

right where the new branches growing up from the fallen trunk

are clearly visible. Above right is a Knob Thorn (Acacia nigrescens)

showing recent elephant damage.

In forest good examples of coppicing trees are

African Wild Peach (Kiggelaria africana), Forest

lemonwood (Xymalos monospora ), African Assegai

(Curtisia dentata) and Black Stinkwood ( Ocotea bul-

lata). In fact in our South Africa forests almost all

the trees are capable of coppicing certainly when

young, but some are able to coppice as an age sur-

vival strategy. Notable exceptions are the yellow-

woods which dont

coppice, but there

is always one excep-

tion that proves the

rule the Breede

River Yellowwood

(Podocarpus elon-

gatus), which is not

a forest species but rather a riverine and rocky outcrop spe-

cialist in the fynbos (see box below). Old African Wild Peach

(Kiggelaria africana) trees, shown above, usually have many

young coppice shoots, and when the old stem dies, only one

of these coppice shoots becomes the next trunk. Forest Lem-

onwoods (Xymalos monospor a), shown left,on the other hand,

often have a few trunks, as when the original single-trunked

tree dies it is replaced by two to five coppice shoots that all

become big trunks.

What are the evolutionary pressures that have resulted

in so many trees with this amazing ability to coppice?

There are clear advantages for coppicing because

if trees are damaged (for example, pushed over in a

wind storm or in a flood, or by an elephant, or browsed

heavily by other herbivores, or burned) then they can re-

sprout and maintain their space in a highly competitive

environment. One must remember that to germinate,

grow and get established trees have to endure a huge

number of tough environmental pressures. (Read the

article The long walk to treedom by Glen Moncrieff,

vol. 96(1), 22-23, in the March 2010 issue of Veld & Flora.)

Once established, trees would not want to vacate their

space, and those that tend to coppice with age have the

advantage of being able to produce fresh young growth

to replace old and decaying woody tissue; and so also

keep their space in the community. I t thus confers on trees a competitive advantage.

The River Thorn (Acacia robusta) shown above, is a survivor that coppices readily. It is a riverine

specialist that is knocked over in occasional flash floods.

learning about biodiversity Veld & Flora FACTSHEET WHY DO TREES COPPICE?

Digging in:Survival

Read moreDiscover more

about our trees

in these articles

in back issues of

Veld & Flora.

The long walk to treedom by Glen Moncrieff, vol.

96(1), 22-23, March 2010.

Why do grasslands have no trees? by Julia

Wakeling, vol. 96(1), 24-25 March 2010.

How we lost the African acacias, vol 98(1), 26

March 2012.

Text and photographs (unless directly credited) by

Eugene Moll.

Download these articles at http://LABpages.blogspot.com.

Please note that we are still using the name Acacia

although in the future it will be changed to Vachelia

orSenegalia.

Coppicing The production of substantial shoots from

adventitious buds that remain hidden beneath the

bark until such time as the tree is damaged basally, or

the tree starts to age and die. It is a form of vegetative

survival and renewal.

Outwitting fire and grazers:Savanna

Coppicing Surviving into old age: FOREST

Taking advantage:Humans

What does that mean?

Humans have used the ability of

many shrubs and trees to coppice

to our advantage. In Curtisia,

if intentionally damaged,

the resulting coppice makes

excellent spear shafts hence

the common name assegai,

and the Zulu-speaking people

have been exploiting this for

centuries. There are many other

examples. In England, farmers

once used coppicing species to

establish living hedgerows, and

plantations of gums are often

managed for coppice growth

because they produce more

poles per hectare than is possible

from one tree.

There is a great variety of tree shapes, sizes and architecture in southern Africa.

Some have fat stems, others are tall and lean, some are short and squat, and

others are relatively unbranched. There are trees that have a sparse canopy

and there are some with a dense, heavy canopy. The huge variety of forms is a

result of evolutionary pressure. Trees have adapted to their environment in

many ways. Adaptations are features that animals and plants have that allows

them to overcome challenges and live successfully in their habitats.

What are the biggest challenges for trees?

Ensuring that future generations survive this involves pollination,

fertilization, seed dispersal and the germination of seeds.

Coping with a whole range of pests and diseases and herbivores for

example, being eaten by an elephant.

Coping with fire and storms.

Competition from other plants for sunlight, water and space.

Trees have evolved many ways of overcoming these challenges, and one of

their survival strategies is the ability to coppice. Many trees coppice. Coppicing

is a survival response to damage by which

trees produce substantial shoots from

adventitious (dormant) buds that remain

hidden beneath the bark until such time

as the tree is damaged, or the tree starts to

age and die. It is thus a form of vegetative

survival and renewal.

RIGHT: Close up of a Mdoni Waterberry

(Syzygiumcordatum)re-sprouting from its base.

A low coppice zone:Fynbos

Trees come in all shapes and

sizes. FAR LEFT: Umbrella Thorn

(Acacia tortilis ). RIGHT: The

Namibian Kobas (Cyphostemma

currorii). Photo: George

Preschern.

Tree A substantial woody plant with a single stem,

usually unbranched for a metre or two, and more than

3-4 m tall. Shrub A woody plant that is many stemmed

from the base.

(In South Africa our National List of Trees includes shrubs

and woody climbers or lianas).

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learning about biodiversity

Earth Starby Wendy Carstens, Melville Koppies guide and Chairman of the volunteer Melville

Koppies Management Committee

Once upon a time in a dark, leafy wood at Melville Koppies, a ray

of sunlight penetrated the trees and lit up a shining ball. It lay in

the leaf litter of the forest, faintly glowing.

At that moment, a tall human in gumboots and overalls came

stomping through the forest, in search of alien weeds. She saw the

shining ball. She picked it up and placed it in the palm of her hand.

The shin ing ball was lying on a soft star-s haped bed. The human

thought it was quite the most beautiful thing that she had ever

seen in the forest. She took it home and placed it on a purple mat.

The shining balls name was Earth Star. It was very unhappy

and lonely on the purple mat. The humans granddaughter tried

to console it, but instead she also got sad. The granny couldnt

stand looking at the sad faces so she took Earth Star back to the

forest where she had found it. Home at last!si ghed Earth Star as

it settled into its warm snug bed of leaf litter on the forest floor.

And the facts

Earth Star is a puff-ball mushroom (a fungus in the division

Basidiomycota) that appears in leaf litter after rain. The outer

covering opens up and peels away like a star. The shining ball

inside is the fruit of the mushroom. Tap it gently and brown

smoke puffs out the little holes that look like eyes. The smoke is

full of minute spores the seeds of mushrooms. The seeds will

only germinate in the correct environment which is in the leaflitter of the forest floor after rain. The ball gradually shrivels up

when all the spores have been dispersed. This may take one or

two days.

Linking to the FET curriculum

In the subject English Home Language for Grade 10, under

section 2 Introducing the language learners are required

to Write and present various texts in order to learn how to

construct and communicate ideas. Using the format of this

magazine story about an interesting mushroom that sends a

conservation message to children, your class can learn howto plan such a story, draft it, edit it, proofread it and present

it to each other in the classroom situation.

Lilliputian or fairy gardens are a delightful way to

encourage younger children to start to learn about

and value their natural environment. Having young

granddaughters in particular has made me even more aware of

how much pleasure fairy gardens can give young people, and

their excitement and imagination is most infectious. Moreover,

this is an ideal way to introduce them to the wild and instil in them

an appreciation for the intricacies of ecosystems.

In a fairy garden, the plants making up the tiny community are

all less than 150 mm tall, and the whole garden covers an area of

a few square centimetres. Gardenslike this can be found in many

parts of South Africa and are generally, but not always, confined

to rocky, shaded areas or on large trees, whose trunks and rough

bark provide ideal niches. They are usually best investigated in the

wet season for it is at this time that you will find bright green moss

species growing on the rock or bark, forming a small, tight mat

or covering. Cracks and small crevices can also provide a suitable

habitat for flowering plants. The moss and lichen cover providesthe substrate (rooting medium) for the taller plants when there

are no cracks for soil to accumulate.

The gardens I fi nd par ticularly enchanting are those where the

taller plants are species like sundews ( Drosera), sorrels (Oxalis),

small lilies and irises, and tiny sedges and grasses. In dry areas

the understorey can be made up of pebbles and lichens, and

occasionally some of the more arid-adapted grey-green mosses

that form tight little cushions that are then colonized by small

succulents and seedlings of the shrubby overstorey, or some

species of annuals and hardy ferns. Certainly in all these places

one can find natural bonsais and with thoughtful dialogue one

FairygardensCreate a Lilliputian fynbos garden

by Eugene Moll, Department of Biodiversity and Conservation

Biology, University of the Western Cape

ABOVE: Sundews (Drosera) in a moss bed growing in a seepage area.

MIDDLE: A clump of moss with a tiny tufter sedge.

BELOW:Tiny Erica seedlings look like miniature fir trees. Photos: Eugene Moll.

BELOW LEFT: In drier areas in the Cape you would find plants like ericas, daisies,

mesembs and Cliffortia species in your fairy garden.

can introduce the young and fertile minds to a whole host of

plant-habitat interactions as well as a range of different plant

forms and species.

You can make your own garden to attract fairies to your home and

in so doing, discover the intricacies of plant habitats, ecosystems

and specializations on a micro-scale. If you want a moist garden

you will need a small fish aquarium or a large jar in which you can

build your garden. If you are able to seal the container you will

have a terrarium that you will not have to water very often. Once

you have a suitable container and lid you will need to collect some

rocks and moss from the garden, and look for some suitably small

plants to grow in the moss. If you want an arid garden then a flat

dish or tray will make an idea base to which you can add and build

your basic garden from rocks, sand or pieces of bark. You may

even start to bonsai a suitable South African tree. Given a little

time and imagination your Lilliputian garden will slowly grow and

give you much pleasure, and to add to the fairy ambiance, let your

imagination run wild and add tiny artefacts where your fairies can

rest, sit or hide. The sky is the limit to what you can do to thrill,

entertain and educate the younger members of your family.

Granny was right to take the mushroom back as it is part of the

ecology of the forest. She also didnt taste it because mushrooms

can be very, very poisonous.

ABOVE: Earth Star on its purple mat. Photo: Wendy Carstens.

BELOW: Earth Star in its natural environment: leaf litter on the forest floor. Photo: Wendy Carstens.

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