Ecosystems, Populations and Sustainability

Question 1

What is an ecosystem

Answer 1

-any group of living and nonliving organisms and the interrelationships between them is an ecosystem
-can be on a large scale e.g. grassland or small scale e.g. rock pool, single tree

Question 2

Components of an ecosystem

Answer 2

-habitat- place where organism lives
-population- all of organisms of one species who live in same place, same time and can breed together
-community- all populations of different species who live in same place, same time and can interact with each other
-the role of each species in an ecosystem is its niche
-its impossible to define niche entirely due to abiotic and biotic interactions however it could include things such as how and what it feeds on, how it reproduces etc
-its impossible for two species to occupy exactly same niche in same ecosystem
-ecosystems do not have clear edges; cannot draw line around group of living things and say they only interact with each other

Question 3

Biotic factors affecting ecosystems

Answer 3

-producers= plants which supply chemical energy to all other organisms
-consumers= primary consumers are herbivores which feed on plants and which are eaten by carnivorous secondary consumers; these in turn are eaten by carnivorous tertiary consumers
-decomposers= bacteria, fungi and some animals feed on waste material or dead organisms
-because these components of ecosystem require own source of materials and energy they can affect other organisms food supply
-can also be responsible for predation and disease

Question 4

Abiotic factors affecting ecosystems

Answer 4

-describe the effects of non living components of ecosystems e.g. pH, humidity, temperature
-these can vary in space and time
-such factors could also be disturbance to ecosystem by other factors such as turbulence and storms
-abiotic factors may also be influenced by biotic components
-at extreme values of an abiotic factors, species may perform better or worse or even die
-a generalised curve can be drawn to show effect of abiotic factors on organism activity
-where there is not lethal level at both extremes an organisms response can be plotted differently
-for example at low levels of pollutants an organism may survive without any detrimental effect
-however at high levels, pollutants may be lethal

Question 5

Describe dynamic ecosystems

Answer 5

-because ecosystem change, we refer to them as dynamic
-the non living elements change and living factors grow or die with populations of particular species rising and falling
-in most ecosystems, population sizes rise and fall very slightly or very noticeably
-living things in ecosystem interact with each other and physical environment; any small changes can affect each other
-for example increase predation=decrease prey
-increase nitrogen levels= increase plant growth

Question 6

Cyclic changes

Answer 6

-changes repeat themselves in a rhythm
-for example movement of tides and changes in day length are cyclic as well as predator-prey fluctuations

Question 7

Directional changes

Answer 7

-these changes are not cyclic
-they go in one direction and tend to last longer than lifetime of organisms within ecosystem
-within such change, particular variables continue to increase or decrease
-for example erosion of coastline or deposition of silt in estuary

Question 8

Unpredictable/ erratic changes

Answer 8

-have no rhythm and no directional, constant change
-for example effects of hurricanes or lightning

Question 9

Energy and materials in an ecosystem

Answer 9

-materials are constantly recycling within an ecosystem- nutrient cycles such as nitrogen and carbon are examples
-energy is not recycled- it flows through the ecosystem
-all living things need energy and materials
-energy is captured by plants and photosynthesis and carbon dioxide; such energy is released from glucose during respiration
-products of photosynthesis are not only used immediately for respiration but incorporated into tissues and organs- e.g. cellulose
-mineral ions are also absorbed through plant roots
-the organic and inorganic components of plant make up its biomass- so when plant eaten, its biomass consumer by a primary consumer
-example of flow of biomass through food chain
-each level of a food chain is a trophic level
-tracking how biomass changes in food chain helps us to track movement of materials and energy through food chain

Question 10

Biomass transfers through ecosystems

Answer 10

-at each trophic level some biomass is lost from food chain and therefore unavailable to organism of next trophic level
-at each trophic level living organisms need to carry out life processes
-respiration releases energy from organic molecules like glucose
-some of this energy is eventually converted to heat and materials are lost in carbon dioxide and water
-biomass is also lost from food chain in dead organisms and waste material which is then only available to decomposers such as fungi and bacteria
-this waste material also includes parts of animals and plants that cannot be digested by consumers such as bones and hair

Question 11

Describe the pyramid for ecosystems

Answer 11

• biomass is less at higher levels of food chain
  -when organisms of food chain are about same size this means there will be fewer consumers at higher levels
  -ecologists draw pyramid of numbers to represent this idea
  -area of each bar in pyramid is proportional to number of individuals as an approximation for total biomass at that level
  -pyramids can be drawn for individual food chains or whole ecosystem

Question 12

How to calculate efficiency of biomass transfer

Answer 12

(biomass at higher trophic level/ biomass at lower trophic level) x 100

Question 13

What is productivity

Answer 13

-rate at which energy passes through each trophic level in a food chain is measure of its productivity
-gross primary productivity is rate at which plants convert light energy to chemical energy through photosynthesis
-even at start of food chain this is inefficient

Question 14

MANIPULATING EFFICIENCY: light levels

Answer 14

-light levels limit rate of photosynthesis and hence production of biomass
-some crops are planted early to provide longer growing season to harvest more light
-others grown under light banks

Question 15

MANIPULATING EFFICIENCY: drought resistance

Answer 15

-as well as irrigating crops, drought resistant strains have been bred, for example drought resistant barely, wheat and sugar beet
-water is reactant in photosynthesis when glucose is produced

Question 16

MANIPULATING EFFICIENCY: nutrients

Answer 16

-lack of available nutrients slows down production of biomass through photosynthesis
-crop rotation can help (growing different crop in each field on rotational cycle)
-this stops reduction in soil levels of inorganic materials such as nitrate or potassium
-including a nitrogen fixing crop like peas or beans in that cycle can replenish nitrogen levels
-many crops bred to respond to high levels of fertiliser providing ammonium, nitrate, potassium and phosphorus

Question 17

MANIPULATING EFFICIENCY: pests

Answer 17

-pests like insects or nematodes eat crop plants, removing biomass from food chain and lowering yield
-spraying with pesticides may help
-some plants also bred to be pest resistant or genetically modified with bacterial gene
-e.g. US cotton resistant to bollworm

Question 18

MANIPULATING EFFICIENCY: fungal diseases

Answer 18

-fungal diseases reduces biomass
-fungi cause root rot reducing water absorption, damage xylem vessels interfering with water transport, damage foliage through wilt, blight or spotting directly interfering with photosynthesis, damage phloem tubes interfering with translocation or damage flowers interfering with reproduction
-farmers spray crops with fungicides
-many crops have been bred to resist fungal infections and potatoes genetically modified to resist potato blight

Question 19

MANIPULATING EFFICIENCY: competition

Answer 19

-competition from weeds for light, water and nutrients reduces a crops NPP
-farmers use herbicides to kill weeds
-the herbicide usually binds to enzyme, stopping it from working and leading to a toxic build up of enzymes substrate

Question 20

What is secondary productivity

Answer 20

-transfer of biomass between trophic levels is inefficient
-primary consumers do not make full us of plants biomass- some plants die, consumers do not eat every part of plant and do not digest everything they eat
-even when food is digested and absorbed most of it is respired with only small amount contributing to increase in biomass and being available to next consumer in food chain

Question 21

How do humans manipulate energy transfer (improve secondary productivity)

Answer 21

-a young animal invests a larger proportion of its energy to growth than an adult. Harvesting animals just before adulthood minimises loss of energy from food chain
-selective breeding has been used to produce improved animal breeds with faster growth rates, increased egg production and increased milk production
-animals may be treated with antibiotics to avoid unnecessary loss of energy to pathogens and parasites
-mammals and birds waste a lot of energy finding food and keeping their body temperature stable. Zero grazing for pigs and cattle farming maximises energy allocated to muscle by stopping animals from moving about, by supplying food to them and by keeping environmental temperature constant

Question 22

Role of organisms in nitrogen cycle

Answer 22

-azotobacter- convert atmospheric nitrogen to ammonia
-rhizobium- fixate nitrogen
-nitrosomonas- convert ammonia to nitrites
-nitrobacter- convert nitrites to nitrate

Question 23

Recycling within ecosystems

Answer 23

-bacteria and fungi involved in decomposition feed in a different way from animals
-they feed saprotrophically so described as saprotrophs
1) saprotrophs secrete enzymes onto dead and waste material
2) enzymes digest the material into small molecules which are then absorbed into saprotroph body
3) having been absorbed, the molecules are stored or respired to release energy
-if bacteria and fungi did not break down dead organisms energy and valuable nutrients would remain trapped within the dead organisms
-by digesting dead and waste material, microorganisms obtain a supply of energy to stay alive and trapped nutrients are recycled

Question 24

RECYCLING NITROGEN: nitrogen fixation

Answer 24

-although nitrogen gas makes up 79% of earths atmosphere it is very unreactive- impossible for plants to use it directly
-instead plants need a supply of fixed nitrogen such as ammonium ions or nitrate ions
-nitrogen fixation can occur when lightning strikes or through haber process in making fertiliser
-nitrogen fixing bacteria supply rest of fixed nitrogen
-azotobacter are bacteria that live in soil and fix nitrogen gas which is in air, in soil to manufacture amino acids
-nitrogen fixing bacteria such as rhizobium also live in root nodules of plants such as beans, peas have a mutualistic relationship with the plant
-bacteria provide plant with fixed nitrogen and receive carbon compounds such as glucose in return

Question 25

RECYCLING NITROGEN: ammonification and nitrification

Answer 25

-ammonium ions are released through ammonification by bacteria found in dead or waste materials
-rather than getting energy from sunlight some chemoautotrophic bacteria in soil (nitrosomonas) obtain it by oxidising ammonium ions to nitrites
-nitrobacter obtain it by oxidising nitrites to nitrates by a process called nitrification
-oxidation requires oxygen therefore reactions only happen in well aerated soils
-nitrates can be absorbed from soil by plants and used to make nucleotide bases and amino acids

Question 26

RECYCLING NITROGEN: denitrification

Answer 26

-other bacteria convert nitrates back to nitrogen gas
-when bacteria involved growing under anaerobic conditions such as waterlogged soils, they use nitrates as source of oxygen for their respiration and produce nitrogen gas (N2) and nitrous oxide (N2O)

Question 27

Describe recycling of carbon

Answer 27

-carbon is also cycled in a/biotic components of ecosystem
-carbon cycle driven by processes of respiration and photosynthesis with carbon dioxide being the main driving component
-animals, plants and microorganisms respire to release carbon dioxide
-microorganisms are particularly important in decomposition of dead organisms and waste
-terrestrial plants use gaseous carbon dioxide in photosynthesis whereas aquatic plants use dissolved carbonates
-carbon is exchanged between air and water when carbon dioxide dissolves in water and then reacts to form carbonic acid
-carbon also enters rivers and lakes from weathering of limestone and chalk in form of hydrogen carbonate
-combustion of fossil fuels has increased across last century so balance of carbon cycle has changed and atmospheric carbon dioxide levels are higher- responsible for global warming

Question 28

Define climax community

Answer 28

-final stable community that exists after the process of succession has occurred

Question 29

Define deflected succession

Answer 29

-happens when succession is stopped or interfered with such as by grazing or lawn mowed

Question 30

Define pioneer species

Answer 30

-progressive change in community organisms over time

Question 31

How does succession occur

Answer 31

-the island of surtsey in iceland was created by volcanic eruption in 1960s but now home to community of plants
-development of such community from bare ground is known as primary succession and comes about by:
1) algae and lichen begin to live on bare rock- pioneer community
2) erosion of rock and build up of dead/ rotting organic material produce enough soil for larger plants like mosses and ferns to grow; these replace or succeed, algae and lichens
3) in similar way, plants that are larger succeed until a final, stable community is met- called climax community
-succession does not always start from bare ground
-secondary succession takes place on previously colonised but disturbed or damaged habitat

Question 32

Succession on sand dunes

Answer 32

-sand dunes display all stages of succession at same place and time
-sand nearest to sea is deposited more recently than sand further away- shows start of succession to climax community
1) pioneer species like sea rocket and prickly sandwort colonise sand just above high water mark. They can also tolerate sprays of salty water, lack of fresh water and unstable sand
2) wind blown sands build up around base of plants form mini sand dunes. As plants die and decay, nutrients accumulate. As sand dunes gets bigger, plants like sea sandwort and sea couch grass colonise it. They help stabilise the sand
3) with more stability and accumulation of more nutrients, plants like sea spurge and marram grass grow. Marram grass trap wind blown sand with its shoots. As sand accumulates, shoots grow taller trapping more sand, growing the dune
4) as sand dune and nutrients build up, other plants grow. Many are leguminous which convert nitrogen to nitrate. With nitrate available, more plants like sand fescue colonise, stabilising dunes further

Question 33

Population size and carrying capacity

Answer 33

-population size of a species may remain stable, rise and fall suddenly or oscillate up and down with regular pattern
-the balance between death rate and rate of reproduction determines the size of a population
1) lag phase may only be a few individuals who are still acclimatising to their habitat
-rate of reproduction is low and growth of population size is low
2) resources are plentiful and conditions are good
-reproduction can happen quickly, exceeding rate of mortality
-population size increases rapidly
3) stationary phase- population size has levelled out at carrying capacity; the habitat cannot support a larger population
-the rate of reproduction and mortality are equal
-population size therefore stays stable or very slightly fluctuates in responses to small environmental variations each year

Question 34

Limiting factors

Answer 34

-a habitat that has reached carrying capacity cannot support growth in population size due to limiting factors
-some are density independent- act just as strongly, irrespective of the size of population e.g. particularly low temperatures
-other limiting factors are density dependent- the factor influences population more strongly as population size increases
-for example availability of resources like food, water, light, oxygen and shelter may decrease
-similarly as population size increases, levels of parasitism and predation from other species may increase as does competition intensity for resources

Question 35

K strategists

Answer 35

-species whose population size is determined b carrying capacity are called k strategists
-limiting factors exert more significant effect as population size gets closer to carrying capacity, causing gradual level off
-species include birds, larger mammals, elephants, lions and larger plants
-have characteristics of:
-low reproductive rate
-slow development
-late reproductive age
-large bodymass
-long lifespan

Question 36

R strategists

Answer 36

-species whose population increase so quickly that it can exceed carrying capacity of habitat before limiting factors have effect are r strategists
-once carrying capacity exceeded, no longer enough resources to allow individuals to reproduce or even survive
-likewise, build up of waste products may poison the species, entering death phase
-this type of population growth is known as boom and busts
-r strategists such as mice, insects, spiders and weeds exhibit:
-high reproductive rate
-young reproductive age
-quick development
-short lifespan
-small bodymass
-pioneer r strategists colonise a disturbed habitat before k strategists, dispersing to other habitats when limiting factors have effect

Question 37

Predator and prey interactions

Answer 37

-a predator is an animal that hunts others for food
-predation can act as a limiting factors on a preys population size, which in turn effect predator population size
1) when predator population gets bigger, more prey eaten
2) prey population then gets smaller, leaving less food for the predators
3) with less food, fewer predators can survive and their population size decreases
4) with fewer predators, fewer prey eaten and population increases
5) with more prey, predator population gets bigger and cycle starts again

Question 38

Competition

Answer 38

-competition happens when resources are not present in adequate amounts to satisfy the needs of all individuals who depend on those resources
-if resource is in short supply in ecosystem there will be competition between organisms for that resource
-as intensity of competition increases, rate of reproduction decreases because fewer organisms have enough resources to reproduce
-death rate increases because fewer organisms have enough resources to survive

Question 39

Intraspecific competition

Answer 39

-intraspecific competition happens between individuals of the same species
-as factors become limiting, individuals compete- those individuals best adapted to obtaining food survive and reproduce, while those not so better adapted, fail to reproduce or die
-this slows downs population growth and population enters stationary phase
-although there are slight fluctuations in population size during the stationary phase, intraspecific competition keeps population size relatively stable
-if population drops, competition reduces and population increases
-if population increases, competition increases and population drops

Question 40

Interspecific competition

Answer 40

-interspecific competition happens between individuals of different species and can affect both population size of a species and distribution of species in an ecosystem
-if two species have exactly same niche, one is outcompeted by other and dies out or becomes extinct in that habitat; two species cannot occupy same niche
-idea become competitive exclusion principle and explains why particular species only grow in particular areas

Question 41

Small scale timber production

Answer 41

-coppicing provides a sustainable supply of wood
-the stem of a deciduous tree is cut close to the ground
-once cut, new shoots grow from the cut stem and mature into narrow stems
-these can be used for fencing, firewood or furniture
-after cutting them off, new shoots start to grow and cycle continues

Question 42

Rotational coppicing

Answer 42

-to provide consistent supply of wood, woodland managers divide a wood into sections and cut one section each year- rotational coppicing
-by time they want to coppice the first section again, the new stems have matured and are ready to be cut
-in each section some trees left to grow larger without being coppiced- these trees are called standards and eventually harvested to supply larger pieces timber
-rotational coppicing is good for biodiversity
-left unmanaged, woodland goes through process of succession blocking out light to woodland floor, reducing number of species
-in rotational coppicing, different areas of woodland provide different types of habitat letting more light in and increasing diversity of species

Question 43

Clear felling

Answer 43

-in past, large scale production of wood for timber often involved clear felling all trees in one area
-this could destroy habitats on large scale, reduce soil mineral levels and leave soil vulnerable to erosion
-trees usually remove water from soil and stop soil being washed away
-soil may run into waterways, polluting them
-trees also maintain soil nutrient levels though their role in carbon and nitrogen cycles
-clear felling is now rarely used in UK

Question 44

Large scale timber production: selective cutting

Answer 44

-any tree which is harvested is replaced by another tree, either grown naturally or planted
-the forest as a whole must maintain it ecological function regarding biodiversity, climate and mineral and water cycles
-local people should benefit from forest
-selective cutting involves removing only largest most valuable trees, leaving habitat broadly unaffected
-sustainably managing forests involves balancing conservation against need to harvest wood, both to maintain biodiversity and to make woodland pay for itself
-if each tree supplies more wood, less trees need to be harvested
-to achieve this:
-control pests and pathogens
-only plant particular tree species where they will grow well
-position trees optimal distance apart, so they are not in competition for light and grow too thin

Question 45

Fisheries

Answer 45

-the fishing industry has high economic value, not just from sales of fish, but in providing livelihoods for people
-the marine stewardship council has proposed three principles for sustainable management of fisheries:
-fishing must take place at a level which allows it to continue indefinitely. Overfishing must be avoided as it reduces fish populations
-fishing must be managed to maintain structure, productivity, function and diversity of ecosystem; this means there is no permanent damage to local habitat and any effect on dependent species is minimised
-a fishery must adapt to changes in circumstances and comply with all regulations

Question 46

Aquaculture

Answer 46

-aquaculture can also provide sustainable fish stocks
-raising stocks of fish in aquaculture restricts the impact on oceanic fish stocks
-aquaculture is expanding rapidly, particularly in developing world and is expected to feed more people than traditional capture fisheries

Question 47

Preservation

Answer 47

-keeping species and habitats as they are now
-focuses on keeping things natural and eliminating any human effects on ecosystem

Question 48

Conservation

Answer 48

-more active management process involving human intervention
-focuses on maintaining or improving biodiversity including diversity between species but also genetic diversity
-many people believe a preservation strategy will not help as habitats are no longer natural due to human impacts

Question 49

BIODIVERSITY THREATS: overexploitation

Answer 49

-wild populations e.g. cod, for sport e.g. sharks, for commerce e.g. pearls means species harvested at faster rate than they can replenish themselves

Question 50

BIODIVERSITY THREATS: habitat disruption and fragmentation

Answer 50

-result of more intensive agriculture practices, increased pollution or widespread building

Question 51

BIODIVERSITY THREATS: introduced species

Answer 51

-brought by humans, they out compete native species, leading to their extinction

Question 52

BIODIVERSITY THREATS: conservation strategies

Answer 52

-raise carrying capacity by providing extra food
-move individuals to enlarge populations or encourage natural dispersion of individuals between fragmented habitats by developing dispersal corridors
-restrict dispersal of individuals by fencing
-control predators and poachers
-vaccinate individuals against disease
-preserve habitats by preventing pollution or disruption or intervene to restrict progress of succession by for example, coppicing, mowing or grazing

Question 53

Ethics to conserve

Answer 53

-many conservationists argue every species has value and therefore humans have ethical responsibility to look after them- however this is subjective
-they aim to drive governments into prioritising conservation by expression value of conservation in economic terms

Question 54

Economic and social reasons to conserve

Answer 54

-many species have direct economic value by harvesting
-some species have unestimated, unrecognisable value that have potential to provide benefits in future
-many plants and animals provide valuable food source and were originally domesticated from wild species
-genetic diversity in wild strains may be needed in future to breed for disease resistance, improved yield and drought tolerance in plants
-natural environments are a valuable source of potentially beneficial organisms- such as potential medicines
-natural predators of pests can act as biological control agents
-this is preferable to causing pollution with artificial chemicals but few such species are yet being used
-many species also have indirect economic value
-for example insect species responsible for pollination and without harvest fail
-other communities important maintaining water quality, protecting soil and breaking down waste products
-ecotourism and recreation in countryside also have significant social and financial value derived from aesthetic value
-ecotourism depends on maintenance of biodiversity

Question 55

Balancing conflict between conservation and human needs

Answer 55

-balancing competing needs/ requirements for natural resources by humans and other living things is essential to help secure sustainable use of natural resources which is compatible with conservation
-two successful examples of conservation being implemented alongside development are Terai region of Nepal and Maasai Mara in Kenya

Question 56

Describe the Terai region

Answer 56

-the Terai region in South Nepal is made up of marshy grasslands, savannah and forests
-it is densely populated and home to endangered species
-there are many national parks in the region
-for over 10yrs the forests in the Terai region have been under pressure from expansion of agriculture into forested area, grazing from farm animals, over exploitation of forest resources and replacement of traditional agricultural crop varieties with modern ones
-in response, World Wide Fund for Nature (WWF) found rural livelihoods are heavily dependent on forests
-forest can provide people with sustainable source of food, fuel, building materials, medicines etc

Question 57

Conservation of Terai region

Answer 57

-to ensure conservation with development they introduced community forestry initiatives in which local people had rights to exploit forest as well as responsibilities to care
-these communities helped create forest corridors between national parks which are essential to dispersal and survival of tigers as well as taking initiative in counteracting poachers and illegal felling
-forestry work also developed and diversified on and off farm activity, build entrepreneurial skills and marketing schemes
-other contributions to Terai project included construction of waterholes, monitoring endangered species and eradicating invasive species

Question 58

Describe Maasai Mara

Answer 58

-in kenya, famous destination for wildlife watchers with large populations of antelope and other large mammals
-because Maasai Mara combines high endemic poverty with abundant wildlife populations that attract tourism, there has been scope to develop conservation-compatible land use that rewards local people financially whilst conserving habitats and species that are the basis for tourism

Question 59

Conservation of Maasai Mara

Answer 59

-partnerships between conservancies and tourism operators have developed payment for wildlife conservation (PWC) schemes
-conservancies are paid PWC revenue proportional to area of land set aside for conservation
-these conservancies are successful because they have positive social outcomes as well as positive conservation outcomes
-there are some negative consequences of conservancies
-landowners must move their livestock out during tourist season leading to increased stocking densities outside reserve with no PWC
-likewise, landowners forced to settle elsewhere and there are constraints on how to use land

Question 60

Controlling effect of human activities

Answer 60

-human activities can affect populations in a number of different ways including habitat destruction, competition for natural resources, hunting and pollution
-to overcome these problems some areas are protected such as national parks/ reserves, green belt land, world heritage sites, marine protected areas and areas of outstanding natural beauty
-there is also legal protection of endangered species and eradication of invasive species

Question 61

GALAPAGOS ISLANDS

Answer 61

-galapagos islands have high numbers of native species including giant tortoises and darwin finches
-unfortunately many species are endangered
-human population has grown in response to increased demand for marine products and increased tourism

Question 62

GALAPAGOS ISLANDS: habitat disturbance

Answer 62

-population size increase has placed huge demands on water, energy and sanitation services- more waste and pollution have been produced and demand for oil increased
-building and conversion of land for agriculture has caused destruction and fragmentation of habitats
-forests of unique species have been almost eradicated on Santa cruz to make way for agricultural land

Question 63

GALAPAGOS ISLAND: over exploitation of resources

Answer 63

-whaling boats and fur traders killed 200,000 tortoises in less than half a century
-charles darwin research station has captive breeding programme to supplement tortoise number
-fishing for exotic species has depleted populations
-depletion of sea cucumber has drastic effects on underwater ecology
-hunt for shark fin decreased shark species numbers

Question 64

GALAPAGOS ISLANDS: effects of introduced species

Answer 64

-as well as out competing local species, island species can eat native species, destroy native species habitats or bring disease
-cats hunt a number of species including lava lizard and iguanas
-goats transform forest into grassland leading to soil erosion
-red quinine invasive species

Question 65

GALAPAGOS ISLANDS: managing effects on human activity

Answer 65

-to prevent introduction and dispersion of introduced species and treat problems caused by such species
-search arriving boats and tourists for foreign species
-natural predators have also been exploited to reduce damage caused to ecosystems by pest populations- controlled release of a ladybird wiped out a scale insect which was damaging plant communities
-culling has also been successful against feral goats on Isabella Islands
-reserve is managed by national park service, charles darwin research station and locals

Question 66

ANTARCTIC

Answer 66

-not governed by any one country but countries have research stations there under the terms of Antarctic treaty
-as such, continent relatively untouched by human influence but with increasing tourists and scientists and with increased interest from fishing industry it remains important to actively protect the ecosystem and biodiversity within it

Question 67

ANTARCTIC: krill

Answer 67

-krill are tiny shrimp like organisms which provide for whales, seal, penguins, albatrosses, and squid
-krill used to make nutritional supplements and for animal feed
-recent changes in technology mean large amounts of krill can be harvested very quickly and easily
-fishing boats tend to congregate in areas with highest krill
-however natural predators krill cannot adapt to easily find krill elsewhere
-to avoid overexploitation, trigger level catch size in particular areas- when met, fishing must be conducted equally across all areas up to total catch limit

Question 68

ANTARCTIC: protected areas

Answer 68

-to protect whales and marine environment a series of protected areas have been established
-established international whaling commission
-within sanctuary it is illegal to hunt and kill whales although monitoring of whaling activity still needs to be maintained to ensure the sanctuary is effective

Question 69

ANTARCTIC: albatrosses and pretrels

Answer 69

-they are threatened by human activities including pollution, hunting and poaching for eggs, habitat destruction and introduction of non native predators
-biggest threat is long line fishing- fisherman trail long fishing line behind boat with baited hooks- birds try eat hooks and swallow
-to reduce number of deaths, boat can use bird scaring lines and streamers, weighted lines which sink more quickly out of reach of birds
-use lines at night to avoid albatross breeding and nesting time

Question 70

LAKE DISTRICT

Answer 70

-lake district contains rich biodiversity of species and habitats
-whole national park is designated an environmentally sensitive area
-however without grazing causing deflected succession much of the land would revert to climax community of oak woodland
-financial incentives are available to farmers to reduce chemical use, care for heathermoor, wetland, meadows and native woodland

Question 71

Solutions to reducing biodiversity in lake district

Answer 71

-limited biodiversity of spruce and pine= initiatives to vary planting and felling patterns
-invasive species outcompete native species= physically removed by conservation workers
-limestone pavement with fissures allows rare ferns and butterflies to thrive= legally protected
-meadows support rich diversity= farmers paid to maintain hay meadows
-heathland important for butterflies, moths, beetles, birds etc= maintain areas of different ages, managed by grazing, financial incentives provided to farmers to prevent overgrazing
-mires nutrient poor, waterlogged ecosystems with thriving lichens, mosses, liverworts= mires managed with artificially controlled water levels
-cliff, rock communities provide rich diversity= protect them with seasonal restrictions and paths maintained to prevent people walking off park

Question 72

SNOWDONIA NATIONAL PARK

Answer 72

-snowdonia in north wales attracts walkers and climbers
-mount snowdon has footpaths that are maintained to ensure rare plants are not trodden on
-gutters take water from path
-prevent erosion by clearing rubbish
-reduce sheep grazing to protect rare plants
-feral goats are problem so monitored
-farmers encouraged to plant hedges and encouraged woodland
-moorland and bog provide nesting sites for rare birds like kestrel and hen harrier

Question 73

Management of Snowdonia

Answer 73

-farmers dig open drain ditches to dry land, however increase SRO= drainage ditches blocked by hay bales
-conifers dry out moorland= trees cut down, branches used to block drainage ditches to slow water and hence keep land moist
-moorland was burnt to provide varied habitat but sheep graze and accidental fires high risk= burning controlled fires before heather gets too old and dry important to prevent such damage