HIGHER

ENVIRONMENTAL

SCIENCE

Unit 1: Living Environment

Revision Notes

oak tree

leaf-eating insect

shrew

fox

ECOSYSTEM DEFINITIONS

• Species - organisms which can breed successfully and produce fertile offspring

• Population - a group of organisms of the same species

• Habitat - a place where an organism lives

• Community - all of the animas and plants in a habitat.

• Ecosystem - the community and the habitat. It can also be described as all of the

living things together with the non living environment

• Niche - is the role occupied by an organism in a habitat - what it eats, what preys

on it and where it lives (e.g. tree bark)

• Ecology - the study of ecosystems and the relationship between organisms and

their environment

FOOD CHAINS & FOOD WEBS

• The source of energy for a food chain / web is always the sun.

• A food chain shows the relationship between organisms which pass on their energy

by feeding

• The arrows in a food chain indicate the direction of energy flow e.g.

• A food web shows all the possible feeding relationships in an ecosystem or habitat.

The term autotroph or primary producer means a green plant which is able to

produce its own food by photosynthesis.

A heterotroph or consumer means an

animal which depends on other living

things (plants or other animals) for its

food. There are 3 types of consumer:

• Carnivores prey on other animals

• Omnivores eat both plants and

animals

• Herbivores eat plants only:

The owl is the top predator in this food web

The levels within a food web are

known as trophic levels

2

ENERGY TRANSFERS

• As energy flows through a food chain a lot of energy is "lost". Usually a maximum of

10% of energy available is passed on to the trophic level above for new biomass

• Energy is lost as heat, movement and undigested waste (NB not death, excrement

and faeces as this is still food for microbes, bacteria and other decomposers).

• Food chains can only support 6 trophic levels before all the energy is used.

• Short food chains (with only 2 or three arrows) are more energy efficient and waste

less energy than longer chains.

• Photosynthesis is a critical process in food webs, where green plants and certain

other organisms transform light energy into chemical energy.

carbon dioxide + water glucose + oxygenLight energy

chlorophyll

• Respiration occurs in cells or organisms, it is the chemical process by which organic

compounds (sugars) release energy for their metabolism.

glucose + oxygen carbon dioxide + water + energy

• Productivity is the amount of solar energy that is incorporated into biomass.

• Gross productivity is the energy "fixed" by the producers in photosynthesis and

stored as chemical energy in glucose.

• Net productivity = Gross productivity - Losses (due to respiration and heat )

• Endotherms are warm blooded animals (mammals, birds) which use more energy for

heat and respiration, so have to eat more food to survive. As a response to this some

species migrate, hibernate or lower their metabolic rate to conserve energy during cold

periods and to reduce their energy demand. Food webs with many endotherms are

often short in length (3 or 4 trophic levels)

• Ectotherms are cold blooded animals (e.g. fish, reptiles) which use less energy for

daily activities. They often survive long periods without food. As they struggle to

regulate their temperatures they can bask in sunlight or seek shade to warm up or cool

down. Food webs with ectotherms are often longer in length.

Decay Processes

Decay is an essential life process, which helps to digest food, and recycle materials

which ensure the energy in dead material is still available to food webs. Decay is the

work of two main groups:

• Decomposers includes fungi and bacteria (single celled organisms) which break

down organic matter chemically by releasing enzymes to speed up chemical reactions.

The soluble components can be absorbed by these micro-organisms.

• Detritivores are larger organisms which feed on detritus (dead material) e.g.

earthworms (break down leaves); maggots (fly larvae which eat animal tissue) and

woodlice (eat dead wood). They also help break down organic matter into smaller

pieces, so increasing the surface area for the bacteria and fungi.

3

ECOLOGICAL PYRAMIDS

Energy flows in ecosystems can be shown using pyramids:

1. Pyramid of Numbers

This is a very simple way of showing the number of organisms at each trophic level.

Pyramids of numbers are often triangular (or pyramid) shaped, but can be almost any

shape, depending of the size of the organisms. In particular very large producers

(like trees) and very small consumers (like parasites) cause inverted pyramids.

The drawbacks with a pyramid of numbers is that they do not consider the size of

organisms or the energy transferred.

mice

snails

grass

parasites

caterpillars aphids

2. Pyramid of Biomass

This is another fairly simple way of

showing the number of organisms at each

trophic level. The pyramid always narrows

towards the top showing energy loss at

each trophic level. However it doesn't

reveal anything about the chemical

composition of organisms and how much

energy is passed on (fat, protein); they

also don't consider ecosystems with a

high turnover rate such as grass in a field

with an apparent low biomass.

3. Pyramid of Energy

This is the most reliable pyramid and

represents the amount of energy flowing

from one trophic level to the next. It is

usually expressed in kilojoules per metre

squared per year (kJ/m2/year). Since

energy is always lost at every trophic

level, they always form upright pyramids

4

INTERDEPENDENCE

All organisms are connected to other organisms by their need for food, this creates

food webs - the simplest form of interdependence. Organisms are also

interdependent when resources are scarce (e.g. food, space, water, shelter and light)

and they will compete for them and given adequate resources and an absence of

disease or predators, populations of organisms in ecosystems can increase at rapid

rates.

The maximum number of species an ecosystem can support is known as the

carrying capacity. Finite resources and other factors limit their growth.

Population Dynamics

Population sizes of species groups change over time. Density-dependent factors

are factors (usually biotic factors) that control the growth of large populations, which

are related to the number of species living within a certain area

1. Predator-Prey Relationship

If the prey population increases, then there is more food for the predators, and their

numbers will increase as there is more food for their offspring. However as more

predators feed, available prey stocks will decline. Decreased availability of food then

will cause predator numbers to fall back. There is often a time lag between the

predator and prey numbers as each has to complete a breeding cycle for the impact

to take effect.

2. Competition between Species

There are 2 main types of competition:

• Intraspecific competition occurs between member s of the same species, who

may compete for food, light, nesting sites, mates. Many species adapt to this be

being territorial, to avoid direct competition with a member of the same species.

• Interspecific completion occurs between members of different species e.g. red

and grey squirrels. The alien grey species out competes the grey for food and also

transmits the papoxvirus which is often deadly for the red squirrel leading to a

dramatic fall in its numbers across the UK.

5

Lag time

3. Symbiotic Relationships

A symbiotic relationship (symbiosis) is a close and often long-term interaction

between two different biological species. There are three types:

4. Disease

High population density of a species can allow infectious disease to be transmitted,

particularly where there is a shortage of food and organisms are malnourished and

cannot fight off infections. Parasites are also easily transmitted. This is often a

natural check on population growth.

5. Toxic Waste

At high population densities, waste products from organisms build up, creating

poisonous conditions which prevent further growth of the population.

Symbiosis Relationship Example

Mutualism Where both organisms

benefit from each

other

Lichens consists of both a fungus and an

alga. The fungus attaches itself to objects

and helps protect the alga. In return the

alga photosynthesizes, producing food for

the fungus

Commensalism When one organism

benefits but the other

is largely unaffected

Cattle egrets (a small type of heron) feed

in pastures next to livestock, which stir up

insects as they move. The cattle are

largely unaffected

Parasitism Where one organism

benefits at the

expense of another

(the host), although

killing the host will not

benefit the parasite

Roundworms and tapeworms (endo-

parasites) live inside the internal another

(the host),organs of mammals e.g. small

intestines of dogs. They survive by

drawing nutrients from digested material

from their host.

6

Density Independent Factors

These are usually abiotic factors

(including temperature, rainfall, pH,

oxygen concentration and salinity)

which limit the size of a population, but

are not dependent on the number of

individuals in the population. Many

abiotic factors vary with the seasons,

and this can cause a seasonal variation

in population sizes as warmer, brighter

conditions promote growth and

reproduction.

BIODIVERSITY

Biodiversity is the total variety of life in an ecosystem or on the earth. It is important for

ecosystems to have biodiversity because it helps to maintain stability in ecosystems

Biodiversity is important to humans because it helps support a range of ecosystem

services, which include:

• Resource provision e.g. the production of food resources and soils

• Regulating e.g. the control of climate (by photosynthesis) and disease

• Supporting services e.g. nutrient cycles and pollination

• Cultural services such as tourism and recreational benefits

Changes in Scotland

During the Holocene period (the time since the last Ice Age ceased around 12,000

years ago, Scotland has gone through a number of changes, natural and man made.

7

Years Ago Changes

12,000 Climate is tundra like (mild summers, cold winters) , supports some insect

and plant life. Elk, bear, reindeer and snowy owl resident.

10,000 Last of the ice goes and Caledonian Pine Forest becomes widespread,

Woodland mammals and birds arrive - roe deer, wildcat, red squirrel, pine

marten, capercaillie and crossbill. Tundra retreats uphill.

8,000 Rising sea level makes Britain an island.

6,000 Temperatures are 2°C warmer than present. It is also wetter and the area

of bog increases. Forest grows up to 610m above sea level.

4,000 It becomes drier and forest increases as bogs shrink. Trees grow up to

1000m on hillsides.

2,500 A return to the cool, wet weather that continues to the present day. The

treeline stabilises at 600m and moor increases. Humans start to influence

vegetation - deforestation for firewood and for land for agriculture..

1,500 Widespread use of tools and farming, following Roman colonisation.

500

(1500 AD)

By 1600 only 5% of ancient woodland remains. Farming systems have

developed with crops such as oats, barley; farm animals domesticated.

250

(1750 AD -)

Highland Clearances - landowners evicted crofters from their land to

make way for sheep; triggering migration to cities and overseas (USA,

Growth of the Sporting Estate - Victorian desire for recreation (wealthy).

Woodland cleared for heather moorland (grouse habitat)

Agricultural & Industrial Revolution. Urbanisation due to rise of heavy

industries e.g. Glasgow / Clydeside. Migration from rural areas to towns

100

(1900 AD -)

Continued urbanisation and growth of towns; massive increase in car

ownership and road network. Huge changes in farming since WW2 -

larger fields, fewer hedges, mechanisation and use of agrochemicals.

Also growth in forestry; aquaculture and tourism / recreational activities

HUMAN IMPACT ON BIODIVERSITY 1

Issues Impact Solutions / Strategies

1. Climate Change

Attributed to

increase in

greenhouse gases

(CO2, methane,

CFCs) through

combustion of fossil

fuels in vehicles,

factories and power

stations, increased

deforestation and

agriculture (rice

fields and livestock

farming create

methane)

• Sea level rise and flooding

of low-lying areas due to

thermal expansion of

oceans and melting of land

based glaciers

• Acidification of oceans

(more CO2 absorbed)

• Increased extreme events

e.g. drought (African Sahel)

and flooding

• Increased hurricane and

storm activity (more energy

in atmosphere)

• Extinction and more

endangered species e.g..

polar bear (needs ice caps)

• Range of species changing

(moving north to warmer

climate

• Increase in pests and

disease that can survive

milder winters

• Increase in invasive/alien

species

• Crops such as rapes may

be able to be cultivated

further north (e.g. British

Isles)

• International co-operation to

reduce greenhouse gas

emissions. UN efforts to

achieve consensus have not

been adopted globally (USA,

China did not sign Kyoto)

• Tax systems to penalise

polluting activities (road tax,

landfill tax)

• Move to renewable energy

supplies (HEP, solar, wind)

• Reduce resource needs by

recycling and reusing

resources

2. Acid Rain

Gases released by

industry and transport

(nitrogen and sulphur

oxides) dissolve in

rain lowering pH

• Aquatic ecosystem are too

acidic for fish and other life

• Acidic water absorbs the

(toxic) aluminum that makes

its way from soil into lakes

and streams .

• Trees are stressed and

struggle to resist disease and

have difficulty seeding /

reproducing

• Add lime to affected areas

(expensive and needs to be

continually repeated)

• Fit scrubbers to catch pollutants

from power stations

• Catalytic converters now

standard on cars

• Legislation to reduce pollution e.g.

UK Clean Air Acts

• Switch to renewables (e.g. wind power)

Issues Impact Solutions / Strategies

3. Agriculture

Fertiliser usage

• Excess fertilisers cause algal

blooms and eutrophication

(reduced O2 in aquatic systems)

• Reduced light in ponds and

streams - fall in biodiversity

• Monitor pollution levels (e.g.

release of slurry into river

systems)

• Create Nitrate Vulnerable Zones

- restrict use of fertiliser run-off

Pesticide usage • Bioaccumulation - the

accumulation of a chemical in

the tissue of an organism.

• Biomagnification - the

increased concentration of a

toxin the higher an animal is

on the food chain (top

predators e.g. birds prey).

• Cannot be broken down or

digested in animal tissues

• Pesticides (neonicotinoids)

cause harm to pollinators

(bees), reducing crop yield

• Regular monitoring of insect

(bee) population to gauge

impact

• EU has banned certain

pesticides (neonicotinoids)

Hedgerow removal

and changing land

use

• Loss of habitat, food supplies,

nesting sites

• Windbreaks removed - causes

soil erosion

• Subsidies and grants for farmers

to move to sustainable

practices (restoring wild flower

meadows and hedgerows)

4. Urbanisation • Sewage / wastewater reduces

biological O2 demand - causing

eutrophication

• Heavy metal toxins released

from factories and industry

• Thermal pollution - changes in

temperature from factories Air

pollution and smogs reduce

atmospheric quality

• Loss of open spaces and trees

for construction

• Fragmentation of habitats

• Transport blocks wildlife

routes, noise, causes roadkill

• Light pollution can upset and

disorientate birds.

• Creates habitats and food

sources for some species

(gulls, pigeons, rats) who have

thrived

• Monitor water and atmospheric

quality (in Scotland this

function is performed by

SEPA) - fines for polluters

• Create green corridors and

underpasses along roads and

railways to allow wildlife (e.g.

mammals) to migrate

• Promote use of public

transport to reduce vehicle

usage

• Reduce landfill and waste

dumping (encourages vermin)

through recycling schemes

Human Impact on Biodiversity (continued) 9

SUCCESSION

This is the process by which a habitat changes over time as different plants get

established. There are two types:

1. Primary succession occurs in areas where there is no soil or bare rock

2. Secondary succession occurs in areas where soil is already present and there

has been disruption to the ecosystem (e.g. fire).

There are a number of stages (or seres) in succession:

Climax communities, the end point of succession, have a number of characteristics:

• They are self sustaining ecosystems, replaced only by themselves

• The area usually has the greatest biodiversity and the tallest species

• It is in balance /equilibrium with its environment

Human Intervention in Succession

Climax communities are subject to change, particularly through the action of humans.

Where human activity has prevented the ecosystem from developing further, a

plagioclimax develops. Examples include:

1. Heather Moorlands

Heather moorland is managed by humans for grazing and for shooting game,

principally grouse. Gamekeepers will burn patches of heather (known as muirburn)

to create different types of habitat and cover for grouse as burning stimulates

secondary succession and it can also remove long grasses which harbour ticks and

parasites which can affect livestock (sheep). There are restrictions on muirburn and it

can only occur in winter (outside nesting seasons).

2. Chalk Grasslands

Human activities (principally grazing) and the influence of rabbits prevent the

development of the scrub woodland climax community of beech and box . The

grassland ecosystem which is allowed to prevail (by conservationists) actually

supports a wide diversity of flowers (orchids), insects and butterflies, which thrive in

the thin, but well drained alkali soils. Some of these landscapes have been lost for

arable farmland since WW2.

1010

Primary coloniers Climax communityIntermediate colonisers

Pioneer species which

can adapt (to the lack

of soil)

Taller plants which take hold

in deeper soils formed as

pioneer plants die off

The end point of succession

(usually woodland)

Zone Embryo/Fore

Dunes

Yellow Dune Grey Dunes &

Dune Slacks

Climax

Changes

inland

Main

Plant

Types

• Frosted orache

• Saltwort

• Sandwort

• Sea rocket

• Sand couch

• Lyme grass

• Marram grass

(80%)

• Sea Holly

• Sand sedge

• Ragwort

• thistles

Dunes:

• Lichens & Mosses

(grey colour)

• Red fescue

• Dandelion

Slacks:

• Cotton grass

• Reeds & Rushes

• Willow

• Heather

• Gorse

• Dog Rose

• Sea buckthorn

• Oak

• Scots Pine

Plant

Features

&

Adaptions

• Scattered

individuals (lack

nutrients)

• Alkaline

tolerance e.g.

sea rocket

(shells)

• low growing (out

of wind)

• Salt tolerant

(sea spray)

• Waxy leaves

(reduce

moisture loss) -

drought tolerant

plants

• Marram grass

thrives on being

buried by sand

• Underground

rhizomes

stabilise sand

and dune system

• Long tap roots

(probe for

moisture)

• Inrolled leaves

(reduce water

loss)

• Stabilising plants like

dandelions succeed

marram as it dies out

- increased soil depth

and humus

• Surface lichens give

dune grey colour

• Increasing shelter

restricts supply of sad

blown from shore

• Damp hollows

(slacks) colonised by

cotton grass and

rushes, thrive in wet

conditions

• Woody

perennials plus

understorey -

heathland and

woodland

• Increased range

of species due

to increased

organic matter

in soils; soils

which prefer

more acidic

conditions

(heather)

SUCCESSION ON SAND DUNES

Young / fore dunes oldest dunes

pH declines

Salinity decreases

Age of dune increases

Available nutrients increases

Available fresh water increases

Humus content (soil increases)

Shelter increases

11

INDICATOR SPECIES

Some organisms only thrive well under certain environmental conditions. These are

known as indicator species as their presence (in numbers) shows a particular

condition relating to the environment. Indicator species must be easy to obtain and

study (e.g. large fish are not used as they are more difficult to catch)

Fresh Water Indicators

The diagram below shows how species change after sewage enters a river

Waterlouse

Mayfly nymphs1

23

4

mayfly

nymph

waterlouse

rat-tailed

maggot

1. Before the sewage outfall the river is clean and well oxygenated. Species such as

mayfly and stonefly nymph thrive in the clean conditions.

2. The river is badly polluted and only pollutant tolerant species such as rat-tailed

maggots and sludgeworms can survive in the dirty water

3. Pollution starts to decrease; organisms such as waterlouse and bloodworm

which can adapt to slightly polluted conditions and lower oxygen levels thrive.

4. The river recovers its original state and clan water species such as mayfly

nymphs return

Lichens

Lichens are a very useful indicator

species as they can indicate the

presence of pollutants (sulphur

dioxide) in the atmosphere: Different

types of lichens differ in their

sensitivity to SO2; crusty lichens

indicate an area as highly polluted as

they will often be the only species

prevalent, hairy lichens are found in

areas free of atmospheric pollution.

12

IMPACT OF NON-NATIVE SPECIES 13

A non-native species (also known as alien or invasive species) is a species that has

been introduced into a country by human intervention (deliberately or accidentally)

since the end of the Ice Age 10,000 years ago. Non-native species have been brought

to the British Isles by various groups e.g. the Roman introduced the rabbit and the rat

was introduced during the Middle Ages.

It is estimated that non-native species these cost around £1.7 billion each year to the

economy. Their impact on biodiversity could be much greater. Examples include:

Non-native species Impact Management Strategies

Grey Squirrel

(Introduced from

North America

during the 19th

Century by

landowners)

• Outcompetes native red

squirrel for food and nest

sites

• Carries squirrelpox virus -

deadly to red squirrels

• Bark stripping kills trees

• Trapping and culling

(expensive)

• Offence to release in the wild

once trapped

Sika Deer

(First reported in late

1800s, brought in

from eastern Asia.

Population now over

25,000)

• Damage woodland (through

ring barking)

• Carries a worm parasite

which can infect livestock

• Hybridisation with native red

deer population

• Cause road accidents

• Culling (but difficult to do due

to hybrids with red deer)

• Large fences keep deer out

• Protecting tubing on young

tree samplings to prevent

deer grazing

Rhododendron

Ponticum

(Introduced during

18th century as an

ornamental addition

to large estates)

• Outcompetes native species

(nothing grows below it)

• No benefit to native wildlife

• Spread rapidly - tubers

• Harbours disease parasite

which affects oak and beech

• Cutting and burning

• Cutting and drilling stumps

and injecting with herbicide

("Round Up")

• Spraying regrowth

• Uprooting (labour intensive)

American Mink -

(Escaped / released

from fur farms in mid

20th century)

• Predates ground nesting

birds and water voles (in

steep decline)

• Threat also to fisheries

• Detecting mink activity

using remote cameras

• Trapping and culling using

“mink rafts”

Signal Crayfish

(First reported in

1976, brought in

from North America)

• Endangers native crayfish,

spreads crayfish plague and

through competition

• Can eat all life in river

systems, decimating

biodiversity

• Burrowing causes riverbank

erosion

• Trapping and extermination

(very difficult)

• Encourage fishermen to

clean apparatus to stop

spread of eggs

• Prevent sale of Signal

Crayfish (restaurant trade)

REINTRODUCING EXTINCT SPECIES 14

Scotland's landscape once hosted species such as beaver, lynx, wolf and brown bear

and there a plans to bring some of them back to the benefit of ecosystems

Species Advantages Disadvantages

Sea eagle

(white-tailed

eagle)

• Estimated 100 breeding pairs

reintroduced since 1975 from

Norway

• Wildlife tourism boosts economy

of Western Isles e.g. Mull

• Concerns from farmers, perceived

threat to lambs

• Persecution, some birds have

been shot and poisoned (although

illegal)

• Cost of monitoring and tagging

birds is expensive

Beaver • Trial project in Argyll perceived to

be a success. Already a

population of 150 (escapees) on

the River Tay

• Felling of riverside trees allows

light through to forest floor;

benefits insects and birds

• Important keystone species

• Flooding of forestry and farmland

areas behind beaver dams

• Affect hydrology and water table

of areas

• Affect spawning grounds of fish

which require fast flowing streams

(dams create slow moving pools)

• Beavers can carry parasites

Lynx • No threat to humans and very

rare to predate farm animals

(feeds on rabbits and small

rodents) Help to control rabbit

population in some areas

• EU Habitats directive requires

UK to investigate possibility of

reintroduction

• Deer killed by lynx in European

studies wouldn't reduce deer

populations to the point that they

would allow forest regeneration.

• Will eat grouse and pheasants,

which causes conflict with

landowners and gamekeepers

• May also predate endangered

capercaillie

• Cost may be prohibitive

Wolf Introduced (successfully) in 1990s

in Yellowstone: Park (USA):

• Wolf tourism brings money into

area ($35 million benefit).

• Control deer population

preventing need for expensive

culls. Forest regeneration occurs

• Deters deer from certain areas

so forest has regrown,

benefitting birds, other large

grazers (bison) - increase in

biodiversity

• Public fear of large predators

(although wolves tend to avoid

humans) - may deter hillwalkers

and affect tourism

• Possible large loss of livestock

(sheep), reducing farmers

livelihoods - would require

expensive compensation

payments

• Any potential ecological benefits

(reduced deer numbers) would

take 50 or 60 years to achieve

• Would require reserves to be set

up to manage properly

CONSERVING BIODIVERSITY 15

The natural environment in Scotland can be conserved and protected by:

1. Statutory (Public) Organisations:

These are organisations which are founded by the Scottish Government (taxpayers). They

include:

(a) Scottish Natural Heritage (SNH).

SNH is the main public for conserving Scotland's wildlife and landscapes. SNH has a

number of functions:

• Providing expert advice to the government

• Educating the public

• Creating species action plans for threatened species

• Controlling and eradicating non-native or invasive species

• Considering the reintroduction extinct species back into Scotland

• Managing Scotland’s deer population using culls

• Managing areas with landscape designations

(b) Scottish Environmental Protection Agency (SEPA)

SEPA has responsibility for:

• Monitoring environmental quality (air, water and land pollution). It has powers to

prosecute those who pollute

• Providing advice to the public and business on environmental concerns

• Managing Scotland’s Zero Waste Plan

• Delivering Scotland’s flood warning system

(c) Forestry Commission Scotland (FCS)

The Forestry Commission was created to ensure the nation had a supply of wood after

WW1. Despite reforesting large areas, there was criticism that the use of non-native

species (e.g. Sitka spruce) did not benefit local wildlife and were unsightly scars on the

landscape. The FCS now has additional aims:

• Conservation. The FCS is involved with planting native species (e.g. Scots pine)

and developing habitats working with charities such as the RSPB.

• Tourism and Recreation. Opening up large areas for public enjoyment (e.g.

walking, camping, bird watching, mountain biking)

(d) Marine Scotland

Marine Scotland's purpose is to manage Scotland's seas for prosperity and

environmental sustainability. Functions include:

• Managing sea fisheries and aquaculture (fish farming)

• Controlling marine planning issues e.g. marine renewables

• Providing advice to government and other marine businesses

• Compliance and enforcement (e.g. pollution)

CONSERVING BIODIVERSITY (continued)

2. Conservation Designations

The landscape can be given a number of levels of protection, including:

• National Nature Reserves. Scotland has 55 including Isle of May, Clyde Valley

• National Scenic Areas. 40 in total e.g. Glencoe, Ben Nevis

• Sites of Special Scientific Interest (SSSIs). Over 1400 smaller areas which have

significant plants, animals or geology e.g. Ailsa Craig, River Ayr Gorge. These

areas have special protection; it is illegal to build or develop the area without

permission from SNH.

• Ramsar sites. Voluntary designation for wetland areas (e.g. Solway Firth)

Designation raises awareness of the areas and gives additional protection from

development. Most of these are managed by SNH.

3. Legislation

The environment in Scotland also has a number of laws (legislation) which protect it:

• Wildlife and Countryside Act (1981). This made the collection of birds eggs and

trading wild animals illegal; banned certain types of traps and snares, and made it

an offence to release any non-native species into the wild.

• Environmental Impact Assessments (EU, 1985). Developers (e.g. new road, quarry, factory)

must undertake this to gauge the impact of development on wildlife is to identify the impact of a

development, and to propose means to avoid or reduce the impacts.

• National Parks (Scotland) Act 2001. Allowed for the creation of Loch Lomond and the

Cairngorm National Parks which have strict rules on development (controlled by

National Park Authorities)

• Local Biodiversity Plans (1996). Managed by local councils with other agencies (e.g.

wildlife organisations). The Ayrshire Local Biodiversity Action Plan currently focuses on

improving habitats such as coastal ecosystems, wetlands and meadows to create

habitats for species such as the brown hare, lapwing and water vole. It works with

landowners to achieve this.

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ECOSYSTEM CASE STUDIES

1. Terrestrial Ecosystem: Caledonian Pine Forest (Scotland)

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Habitat: • Short growing season due to altitude and wet climate

• Broken forest cover on Scottish Highlands. Mainly coniferous

species (Scots Pine) due to climate

• Canopy is naturally interrupted to allow light through and

shrubs can flourish.• Abundance of dead and rotting trees

Main species: Producers:

Herbivores:

Omnivores:Carnivores:

Scots pine (keystone species), rowan, willow,

juniper, blueberry, ferns, lichens, mosses

Capercaillie, crossbill, siskin (both finches), red

deer

Red squirrel, pine marten, crested tit

Scottish wildcat, osprey, sparrowhawk, goshawk, otter

Issues / Threats:

• Removal of forest over last 5,000 years for human activities;

only 1% of forest remain in approximately 40 locations

• Unmanaged deer population eats young saplings

• Fragmentation of forest cover

• Hybridisation of wildcat population (breeding with feral

domestic cats) is reducing the gene pool)

• Risk of forest fires (result of increased recreational visitors)

Management Strategies

• Trees for Life charity (working with landowners and other groups

such as SNH, RSPB and the Forestry Commission) aims to

replant 2 million trees to join up habitats and increase the

amount of habitat

• Deer fences being removed (threat to low flying birds such as

capercaillie). Plastic tubes can protect bark of young saplings

• SNH has a Species Action Plan in place, including the

captive breeding of Scottish Wildcat to maintain genes

• Rhododendron removal (non native species on Highland

estates out competes native shrubs) by cutting and using

weedkillers (injected into wood)

• Possible studies into the reintroduction of beaver, wild boar,

lynx and wolf

• Area is protected under the EU Habitats Directive

ECOSYSTEM CASE STUDIES

2. Aquatic Ecosystem: Estuarine Environments (e.g. Solway Firth)

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Habitat: • Mixture of fresh, brackish and saltwater environments

• Variety of habitats - tidal mudflats, saltmarsh, sand dunes and

open farmland

• Very important habitat for migrating waders and wildfowl in

autumn and winter

Main species: Producers:

Herbivores:

Carnivores:

Apex predators:

Plankton, seaweeds, grasses

Mussels, molluscs, lugworm, shrimps, small

fish

Common crab, eel, salmon, oystercatcher,

curlew

Otter, grey seal, heron, peregrine falcon

Issues: • Threats from human activity: urbanisation; industry; dredging;

fish farming, agriculture (pesticides and fertilisers causing

eutrophication); tourism and recreation activities causing

disturbance of wildlife e.g. powerboats

• Waste products from sewage disposal and fishing waste (nets)

• Plastic waste is non-biodegradabale (swallowed and cannot be

digested by organisms)

• Climate change: sea level change and more extreme storms

causing coastal erosion and rapidly changing habitats

• Invasive / non-native species e.g. Chinese mitten crab

outcompetes native species and burrows into river banks

Management Strategies

• Ramsar (wetland) status raises awareness of these unique

habitats and provides funding for conservation e.g. Solway Firth

• Designation as National Nature Reserves and SSSIs, which

restrict development (construction, industry)

• Managed retreat (allow coastal areas to flood naturally) to create

new habitats and use nature as a coastal defence

• Restrict bait collection for fishing during winter - food for wildfowl

• Restrict shooting of wildflowl

• Marine Scotland has legislative powers to manage fisheries and

off shore developments (e.g. coastal wind farms)

• SEPA monitors pollution levels (water quality) and can prosecute

landowners f required

• No take zones (e.g. off Lamlash, Arran) has allowed sea bed

ecosystem to recover naturally once fishing banned

INVESTIGATING ECOSYSTEMS

Plants and animals can be sampled using both quantitative and qualitative

techniques

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Quantitative Techniques

These techniques provide information

about the number (quantity) of species

that live in an area.

Data collected can relate to the

abundance, density, and coverage of

certain species

Qualitative Techniques

These techniques provide information

about the different type of species that

live in an area.

Keys are used to help identify plant

and animal species.

Sampling Methods

Sampling

It is impossible to count all the species in an ecosystem, so sampling is a way of

getting a quantitative measurement which is an estimate of the actual number. It

involves finding the average number of organisms of a species in a particular area

and then multiplying this by the total area being studied. Ideally many samples

need to be taken, repeated and then averaged to ensure the estimate is as reliable

a figure as possible.

Common sampling techniques include:

• Using a transect, a line across a habitat or part of a habitat. The number of

organisms of each species can be observed and recorded at regular intervals

• Using a quadrat, a square of metal or wire which can count the number of plant

species within a defined area

Reliability & Validity

All sampling techniques should strive to ensure:

Reliability. This relates to the sample size and repeating procedures. Results become

more reliable if they are repeated more times and averages taken.

Validity. This correctly tests the aim of the experiment, so all factors are kept constant

aside from those being investigated, only one variable should be changed at a time e.g.

when comparing soil samples from different locations the same size of sample needs to

be taken, using same apparatus to analyse them

Ecosystem Sampling Technique Improving Results

Tree Beating Stick & Tray A walking stick is used to

give the branch of a tree a

few taps.

invertebrates fall on to a

collecting tray or sheet

underneath.

• Take several samples

from different branches

of the same tree

• Use a large tray with

raised edges to stop

other insects crawling in

Soil Pitfall Trap Animals the are active on

the soil surface and leaf

litter fall into the trap (a

sunken beaker). Pitfall

traps should be placed at

random or regular intervals

across the area of survey

• Set up several traps

• Disguise the opening

with a leaf or stone

• Check traps regularly or

put preservative liquid

(ethanol) in the beakers

Tullgren Funnel This can be used to trap

tiny organism which live in

the soil. After a soil sample

has been taken, tiny

creatures in the soil move

down away from the hot,

dry and bright conditions

created by the light and fall

through the sieve into the

collecting beaker.

• Use mesh with larger

holes to allow more

invertebrates to pass

through

• Make layer of soil on

sieve thin

• Run experiment for

longer

• Set up several funnels

Pond /

Stream

Water Net In ponds the net is moved

rapidly through the water,

catching animals which are

transferred into jars.

In streams the net is held

at a fixed position and

invertebrates in the stream

bed can be dislodged by

kicking the pebbles, they

will be carried downstream

into the nearby net (known

as “kick-sweep” method)

• Choose a net with finer

mesh to catch smaller

invertebrates

• Repeat the procedure

many times

Mud Baermann Funnel Used to sample tiny

nematodes (worms) in

mud. A muslin bag with

mud is submerged in a

funnel and the worms sink

to the bottom

• Choose a net with finer

mesh to catch smaller

invertebrates

• Repeat the procedure

many times

SAMPLING ORGANISMS

Methods of sampling will depend upon the ecosystem under investigation:

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SAMPLING ORGANISMS (2) 21

Specialist equipment is required to sample some species plants and animals

Mammal traps The Longworth small mammal trap works by enticing small

mammals into a rectangular tube using food as bait; when the

door is sprung it closes behind the mammal

Moth traps Most moth traps consist of a light to attract the moths and a box

in which the moths can accumulate and be examined later. The

moths fly towards the light and spiral down towards the source of

the light and are deflected into the box.

Camera traps A camera trap is a remotely activated camera that is equipped

with a motion sensor or an infrared sensor, or uses a light beam

as a trigger. Camera trapping is a method for capturing rare or

reclusive wild animals on film when researchers are not present

Bat detector A bat detector is an electrical device used to detect the

presence of bats by converting their echolocation ultrasound

signals, as they are emitted by the bats, to audible frequencies.

However they often only have a range of around 30m.

Electro fishing Electrofishing in rivers uses a direct current electricity flowing

between a submerged cathode and anode. This affects the

movement of the fish so that they are stunned where they can

be caught using a dip net. When performed correctly,

electrofishing results in no permanent harm to fish, which return

to their natural state in as little as two minutes after being caught

MEASURING ABIOTIC FACTORS

Abiotic Factor Sampling Technique / Equipment Improving Results

Soil

temperature

Soil thermometer. Place bulb of

thermometer in soil and take readings

• Repeat and average to give

greater accuracy

• Ensure probes of equipment

are clean before use to avoid

inaccurate readings

Soil moisture Soil moisture probe

pH • Soil pH meter

• Take a sample of soil and add

distilled water and universal

indicator. Compare colour against

pH chart.

• Ensure probes of equipment

are clean

• Avoid using rainwater (slightly

acidic)

Light levels Use a light meter • Repeat and average

• Light meters re difficult to use

(change in cloud cover,

shadows) can influence results

Oxygen

concentration

• Colorimetric methods (chemical

agents react with O2 in the water to

give a colour change)

• Use an electrochemical or optical

sensor to measure O2 levels

• Repeat and average

Salinity • Use a hydrometer

• Use a refractometer (measures how

light is altered by salts in solution)

• Repeat and average

Flow rate

(stream

discharge)

• Use a flow meter

• Calculate average depth across the

stream channel and multiply it by

width to give channel shape.

Mutiply this by the speed (timing an

object to flow a certain distance)

• Ensure sampler does not

stand in front of the flow meter

to reduce (shelter) readings

• Use an object that is heavy

enough to move downstream

(orange not a ping pong ball)

• Repeat and average (floats

can get stuck behind stones

when river levels are low)

Wind speed /

direction

• Speed is measured by an

anemometer and direction by a wind

vane

• Need to be located in an area

which is not sheltered

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How to Measure Soil Fertility (Humus Content)

This can be done by:

• Take a soil sample (damp) and weigh

• Dry in a cool oven and weigh again (allow moisture to evaporate)

• Repeatedly burn off organic content and keep weighing until no change in weight

• Calculate percentages at each stage for water, organic and mineral content (base

don initial damp weight of soil)

USING KEYS 23

Keys are qualitative methods used to identify a species. A key can be branching or a

series of paired statements with simple 'yes / no' answers. They are based on the

physical characteristics of the species to be identified.

1. Branching Tree Example

This tree could help you identify a

new vertebrate. For example, if it

had no fur or feathers and dry skin,

you would follow the right-hand

pathway at the first and second

junctions, but the left-hand pathway

at the third junction. This would

lead you to identify the animal as a

reptile.

2. Paired Statement Keys

Based on physical characteristics, paired statement keys can also be used to identify organisms e.g.

Question 1 Are the leaves like needles?Yes ? go to question 2 No ? go to question 3

Question 2 Are the needles in pairs?Yes ? go to question 4 No ? go to question 5

Question 3 Are the leaves simple or compound (several leaflets)?Yes ? go to question 6 No ? go to question 7

Question 4 It could be a Scots Pine.[Start again.]

Question 5 Are the needles in circular clusters?

Question 6 Is the leaf heart-shaped?