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Module 6- Genetics and Ecosystems > 6.6- Populations > Flashcards

6.6- Populations Flashcards

1
Q

What determines population size

A

The balance between mortality rate and rate of reproduction

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2
Q

Name different ways in which population size can change

A
  • stay stable
  • rise/fall suddenly
  • oscillate up/down in regular pattern
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3
Q

Graph of how many populations grow, explanation

A

A:
- lag phase
- may only be a few individuals who are still acclimatising to their habitat
- rate of reproduction low
- growth in population size slow

B:
- log phase
- resources are plentiful
- conditions are good
- reproduction can happen quickly, rate of reproduction exceeds mortality
- population size increases rapidly

C:
- stationary phase
- population size levelled out to carrying capacity of habitat- habitat can’t support larger population
- rates of reproduction and mortality equal
- population size therefore stays stable (or fluctuates up/down slight due to small variations in environmental conditions

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4
Q

What prevents a habitat that has reached carrying capacity from supporting a larger population

A

limiting factors

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5
Q

Name 2 types of limiting factors

A

Density dependent, density independent

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6
Q

Describe density-independent limiting factors

A
  • act just as strongly irrespective of population size
  • e.g. temperature drop effects same proportion regardless of size
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7
Q

Describe density-dependent limiting factors

A
  • factor influences population more strongly as population size increases
  • e.g. availability of resources- food, water, light, oxygen, nesting sites, shelter
  • similarly, as population size increases, leaves of parasitism, predation, and competition from other species may increase (and with own species for competition)
  • carrying capacity is the upper limit that these factors place on population size
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8
Q

Name 2 types of stratagists

A

R and K stratagists- represent 2 ends of a continuum of strategies adopted by living things

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9
Q

Describe K strategists characteristics

A
  • low reproductive rate
  • slow development
  • late reproductive age
  • long lifespan
  • large body mass
  • examples- birds, larger plants, larger mammals like humans, elephants and lions
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9
Q

Describe R strategists characteristics

A
  • high reproductive rate
  • quick development
  • young reproductive age
  • short life span
  • small body mass
  • examples- mice, insects, spiders, weeds
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10
Q

Describe K strategists population growth

A
  • population size is determined by the carrying capacity
  • limiting factors extert a more and more significant effect as the population size gets closer to the carrying capacity, causing population size to gradually level out
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11
Q

Describe R strategists population growth

A
  • population size increases so quickly that it can exceed the carrying capacity of the habitat before the limiting factors start to have an effect
  • once the carrying capacity has been exceeded, there are no longer enough resources to allow individuals to reproduce, or even survive
  • excessive build-up of waste products may start to poison the species, and they begin to die- entering a death phase
  • population growth called boom and burst
  • most important influence on population growth is the physical rate (r) at which individuals can reproduce
  • this type of growth is characteristic of species with short generation times (e.g. bacteria) and of pioneer species
  • quick population growth means pioneer r-strategist species colonise a disturbed habitat before k-strategists, dispersing to other habitats once limiting factors start to have an effect
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12
Q

R and K strategists population growth graph

A
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13
Q

What is a predator

A

An animal that hunts other animals (prey) for food- predation can act as a limiting factor on preys population size which in turn can affect the predators population size

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14
Q

Describe the stages of predator-prey interactions

A

1) when the predator population gets bigger, more prey are eaten
2) The prey population then gets smaller, leaving less food for the predators
3) With less food, fewer predators can survive and their population size reduces
4) With fewer predators, fewer prey are eaten and their population size increases
5) with more prey, the predator population gets bigger, and the cycle starts again

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15
Q

Predator prey graph, describe conditions of this

A
  • comes from experiment conducted in laboratory, where the predators only ate one type of prey, and predation was the main limiting factor on the preys population
  • however, in the wild, predators often eat more than one type of prey, and there are a number of other limiting factors
  • because of this, studies of predators and prey in the wild yield graphs of a similar, but not so well defined, shape
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16
Q

Predator-prey graph over number of years

A
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17
Q

Describe competition

A
  • happens when resources (e.g. food/water) are not present in adequate amounts to satisfy the needs of all individuals who depend on those resources
  • if a resource is in short supply in an ecosystem, there will be competition between organisms for the resource
  • as the intensity of competition increases, the rate of reproduction decreases (because fewer organisms have enough resources to reproduce)
  • death rate increases (as fewer organisms have enough resources to survive)
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18
Q

Name two types of competition

A
  • interspecific
  • intraspecific
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19
Q

Describe intraspecific competition

A
  • between individuals of same species
  • as factors e.g. food supplies become limiting, individuals compete for food
  • those individuals better adapted to obtaining food survive and reproduce, while those not so well adapted fail to reproduce, or die
  • this slows down population growth, and the population enters the stationary phase
  • intraspecific competition keeps the population size relatively stable but there are slight fluctuations
  • keeps stable as if population size drops, competition reduces and population size increases, and if population size increases, competition increases and population size drops
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20
Q

Describe interspecific competition

A
  • happens between individuals of different species, and can affect both the population size of a species and the distribution of a species within an ecosystem
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21
Q

Describe an example of research into interspecific competition

A
  • Gause (1934)
  • grew 2 species of paramecium- P. Causatum and P. Aurelia, both separately and together
  • when together, there was competition for food, with P.A. obtaining ffod more effectively than P.C.
  • over 2- days, the population of P.C. reduced and died out, while the population of P.A. increased- eventually being only species remaining
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22
Q

Describe Gause’s conclusions

A

Competitive exclusion principle:
- more overlap between 2 species niches results in more intense competition
- if 2 species have exactly the same niche, one is out-competed by the other and dies out or becomes extinct in that habitat- 2 species can’t occupy same niche
- principle explains why particular species only grow in particular places

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23
Q

Why isn’t the competitive exclusion principle always straight forward in the wild

A
  • other reserach suggests extinction isn’t inevitable
  • sometimes, interspecific competition simply results in one population being much smaller than the other, with both population sizes remaining fairly constant
  • also, in lab it is easy to exclude the effects of other variables, so the habitat of the 2 species remains stable
  • in the wild, however, a wide range of variables may act as limiting factors for the growth of different populations and may change on a daily basis or river the course of a year
  • e.g. experiments on the competition between flour beetles Tribolium confusum and T. castaneum initially confirmed the competitive exclusion principle- the T.Cas population size increased while the T.Con population died out, but even a small chang in the temperature could change the outcome, so T.Con would survive instead
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24
Q

Gause experiment/ competitive exclusion principle graphs

A
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25
Q

Flour beetles population interactions graph

A
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26
Q

Describe preservation

A

Maintenance of habitats and ecosystems in their present condition, minimising human impact

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27
Q

Describe conservation

A
  • maintenance of biodiversity, including diversity between species, genetic diversity with species, and maintenance of a variety of habitats and ecosystems
  • involves active human management and intervention
  • change in many ecosystems is inevitable- due to human activity in past and natural succession- very few UK habitats truly ‘natural’- adopting preservation strategy wouldn’t preserve a natural habitat
  • therefore, conservation programs focus on maintaining or improving biodiversity
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28
Q

Describe threats to biodiversity

A
  • over exploitation of wild populations for food (e.g. cod in North sea), for sport (e.g. sharks), and for commerce (e.g. pearls from mussels)- species harvested at faster rate than they can replenish themselves
  • habitat disruption and fragmentation as a result of more intensive agricultural practices, increased pollution, or widespread building
  • species introduced to an ecosystem by humans that out-compete other native species, leading to their extinction
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29
Q

What does successful conservation require

A
  • consideration of the social and economic costs to the local community, and effective education and liaison with the community
  • maintaining biodiversity in dynamic ecosystems requires careful management to maintain a stable community, or even reclamation of an ecosystem to reverse the effects of human activity
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30
Q

List different methods of conservation

A
  • establishing protected areas like National parks, green belt land or sites of special scientific interest (SSSIs)
  • giving legal protection to endangered species, or conserving them ex situ in zoos or botanic gardens
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31
Q

List management strategies for maintaining biodiversity

A
  • 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 of appropriate habitat
  • restrict dispersal of individuals by fencing
  • control predators and poachers
  • vaccinate individuals against disease
  • preserve habitats by presenting pollution or disruption, or intervene to restrict the progress of succession e.g. by coppicing, mowing, or grazing
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32
Q

What does which management strategies are adopted depend on

A

The specific characteristics of the ecosystem and the species involved

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33
Q

Why is simple management sometimes inappropriate, what is done instead

A
  • disruption of a community may have gone too far
  • understanding which species was part of the original community is not always clear, and succession is likely to take a long time before it allows such a community to survive again
  • short-cutting that process requires detailed knowledge of all species involved
  • where environmental conditions have remained entirely stable, it is possible to clean up pollution, remove unwanted species, or reconolise with the original species e.g. from captive breeding programmes
  • however, it is often easier, and more successful, to ‘replace’ a disrupted community with a slightly different community rather than to rehabilitate the original community
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34
Q

Name 3 reasons to conserve

A
  • ethics
  • economic
  • social
35
Q

Describe ethical reasons to conserve, evaluate these arguments

A
  • every species has value- humans have ethical responsibility to look after them

These are subjective arguments- arguments in favour of human activities that work against conservation (e.g. burning fossil fuels, open-cast mining etc) are objective and driven by economics. Expressing the value of conservation in economic terms is more effective in driving governments to prioritise conservation.

36
Q

Describe the nature of economic value of species

A
  • many species have direct economic value when harvested- easiest to measure
  • others may also have direct value that isn’t yet recognised
  • may provide benefit in the future- hard to estimate
37
Q

Describe ways in which species can have direct economic benefits

A
  • many plant and animal species provide a 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 and improved yield in animals and plants, and drought tolerance in plants- likewise, new plant species may be domesticated for food use
  • natural environments are a valuable source of potentially beneficial organisms- many of the drugs we use today were discovered in wild plant species
  • natural predators of pests can act as biological control agents- preferable to causing pollution with artificial chemical, but few such species are being used currently
38
Q

Describe ways in which species can have indirect social and economic benefits

A
  • insect species are responsible for pollinating crop plants- without insects, a species may fail and farmers would go out of business
  • likewise, other communities are important in maintaining water quality, protecting soil, and breaking down waste products
  • evidence that a reduction in biodiversity may reduce climatic stability, with such loss of diversity resulting in drought or flooding and an associated economic cost
  • ecotourism and recreation in the countryside also have significant social and financial value, which derives from the aesthetic value of living things- ecotourism in particular depends on maintenance of biodiversity, and there is even a sizeable industry in natural history books, films, and other media
39
Q

Describe the need for sustainable management of ecosystems

A
  • human population getting larger increasingly quickly- using more intensive methods to exploit our environment for resources
  • such approaches can disrupt or destroy ecosystems, reduce biodiversity, and even completely remove the resource we originally wanted to harvest- our use of natural resources is not sustainable
  • potential conflict between our need for resources and conservation e.g. in wood/timber and fish production
  • however, sustainable management and exploitation of these resources are possible and can mean that biodiversity is maintained, whilst ensuring supplies and maintaining their economic benefits
40
Q

Describe how small-scale timber production can be managed

A
  • Coppicing provides stable supply of wood- stem of a deciduous tree is cut close to the ground
  • once cut, new shoots grow from the cut surface and mature into narrow stems
  • these can be used for fencing, firewood, or furniture
  • after cutting them off, new shoots start to grow again, and the cycle continues
  • Pollarding involves cutting the stem higher up, to prevent deer eating the emerging shoots
  • to provide a consistent supply of wood, woodland managers divide a wood into sections and cut one section each year- rotational coppicing
  • By the 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 are left to grow larger without being coppiced- ‘standards’- eventually harvested to supply larger pieces of timber
41
Q

Describe how rotational coppicing is good for biodiversity

A
  • rotational coppicing is good for biodiversity
  • left unmanaged, woodland goes through a process of succession, blocking out light to the woodland floor and reducing the number of species growing there
  • in rotational coppicing, different areas of woodland provide different types of habitat, letting more light in, and increasing the number and diversity of species
42
Q

Describe traditionally large-scale timber production in the UK, issues with this

A
  • often involved clear felling all the trees in one area
  • this could destroy habitats on a large scale, reduce soil mineral levels and leave soil susceptible to erosion
  • trees usually remove water from soil and stop soil being washed away by rain
  • soil may run off into waterways, polluting them
  • trees also maintain soul nutrient levels through their role in the carbon and nitrogen cycles
43
Q

Describe current large-scale timber production in the UK

A
  • clear felling now rarely practiced in the UK
  • leaving each section of woodland to mature for 50-100 years before felling allows biodiversity to increase
  • however, such a time-scale is not cost-effective
    Instead, modern sustainable forestry avoids this by working on these principles:
  • any tree which is harvested is replaced by another tree, either grown or naturally planted
  • the forest as a whole must maintain its ecological function regarding biodiversity, climate, and mineral/water cycles
  • local people should benefit from the forest
    Selective cutting involves removing only the largest, most valuable trees, leaving the habitat broadly unaffected
44
Q

Describe sustainable management of forests

A
  • involves balancing conservation against the need to harvest wood, both to maintain biodiversity and to make the woodland pay for itself
  • if each tree supplies more wood, fewer trees need to be harvested
    To achieve this foresters:
  • control pests and pathogens
  • only plant particular tree species where they know they will grow well
  • position trees an optimal distance apart- if they are too close, this causes too much competition for light, and they grow tall and thin, producing poor-quality timber
45
Q

Name 2 ways of managing fish stocks

A
  • fisheries
  • aquaculture
46
Q

Describe the impact of the fishing industry

A
  • has high economic value- through both sales of fish and providing livelihoods for millions of people
47
Q

Describe fisheries

A

The Marine Stewardship Council has proposed 3 principles for sustainable management of fisheries:
- fishing must take place at a level which allows it to continue indefinitely- over-fishing must be avoided as it can reduce fish populations to zero- if over-fishing happens, reducing fishing to let stocks recover can rapidly increase productivity and is good for profitability, given high stock valued can support a more efficient harvest- optimum is to maintain fish populations at the carrying capacity of their environment, while fishing continues to harvest fish in the excess of that capacity
- fishing must be managed to maintain the structure, productivity, function and diversity of the ecosystem- means there should not be permanent damage to the local habitats, and any effect on dependent species is minimised
- a fishery must adapt to changes in circumstances and comply with local common national and international regulations

48
Q

Describe aquaculture

A
  • raising stocks of fish in aquaculture restricts the impact on oceanic fish stocks
  • aquaculture is expanding rapidly, particularly in the developing world, and is expected to feed more people than traditional capture fisheries in the near future
49
Q

What is necessary to secure sustainable use of natural resources, name 2 successful examples of this

A
  • Balancing the competing requirements for natural resources by humans and other living things
  • The Terai region of Nepal
    The Maasai Mara in Kenya
50
Q

Describe the Terai region

A
  • In the south of Nepal
  • made up of marshy grasslands, savannah and forests
  • densely populated
  • home to endangered species incl. the Bengal tiger and the greater one-horned rhinoceros
  • many national parks in the region
51
Q

Describe pressures in the Terai region, what has been done in response

A

For 10+ years, the forests have been under pressure from:
- expansion of agriculture into forested areas
- grazing from farm animals
- over-exploitation of forest resources
- replacement of traditional agricultural crop varieties with modern ones

In response, the world wide fund for nature (WWF) found that rural livelihoods are heavily dependent on the forests, which are also home to many of the region’s endangered species

52
Q

Examples of what the Terai regions provide for rural livelihoods

A

The forests can provide local people with a sustainable source of:
- fuel
- animal feed
- food
- building materials
- agricultural and household tools
- medicines

53
Q

What has been done in the Terai region to balance conflicts

A
  • As local people have such a high stake in the forest, the WWF and Nepalese government in the Terai-arc landscape programme focused on conservation of the forest landscape as a whole
  • to ensure conservation with development, they introduced community forestry initiatives- local people had rights to exploit the forest as well as responsibilities to look after it
  • these community groups helped create forest corridors between national parks- essential to the the dispersal and survival of tigers, and taking the initiative in counteracting poachers and illegal felling
  • Forestry work- developed+diversiffied on-and-off farm activity, built entrepreneurial skills, and stimulated small crit and marketing schemes
  • WWF scheme introduced bogas plants and wood-efficient stoves to reduce demand for firewood
  • construction of waterholes, monitoring endangered species, eradicating invasive species
54
Q

Describe the effects of the schemes in the Terai region

A
  • Community involvement combined with non-governmental (WWF) leadership appears to have been successful
  • recent data (from southern Nepal_ suggests tigers are using corridors between national parks and their population size is steadily growing
55
Q

Describe the Maasai Mara

A
  • in Kenya
  • famous destination for widelife watchers
  • large populations of antelope and other large mammals
56
Q

Why is there scope to develop conservation-compatible land use in the Maasai Mara

A
  • combined high endemic poverty with abundant wildlife populations that attract tourism - potential for land-use that rewards local people financially, whilst conserving habitats and species that are the basis for tourism
57
Q

What happened to the Maasai after 1945

A
  • After creation of national parks in 1945, the remaining Maasai land was held in trust till 1968, when the lands were designated as ‘group ranches’
  • worried about their tenure on the land, many Maasai took individual title over smaller portions of land
  • this triggered land-use change, including intensification of agriculture
  • this limited wildlife to increasingly small islands and contained the mobility of livestock
  • e.g. wheat farms occupy 40000 acres of the previous wet-season-range of migratory wildlife- the population of wildebeest that use the wet-season-range shrank decreased from 150000 in 1977 to 40000 in 2010
  • the density of other wildlife has dropped 65% over the last 30 years, while the density of sheep and goats increased
58
Q

What happened in the Maasai Mara Reserve to combat the loss of wildlife

A
  • in 2005, several land owners to the north of the MMR consolidated their land to form conservancies, in order to generate tourism income
  • partnerships between conservancies and tourism operators have developed payment for wildlife conservation (PWC) schemes
  • Conservancies are paid PWC revenue proportional to the area of land set aside for conservation
  • these conservancies are successful, because they have positive social outcomes, as well as positive conservation outcomes
59
Q

What are negative consequences of the conservancies in the Maasai Mara

A
  • land-owners must move their livestock out during the tourist season, which leads to increased stocking densities outside the reserve, where no one receives the PWC money
  • likewise, land-owners are often forced to settle elsewhere, and there are constraints on how they use their land
60
Q

Describe the relationship between livestock and conservation in the Maasai Mara

A
  • livestock have been seen as a problem for conservation
  • However, there is evidence that limited livestock grazing can have positive impacts on diversity
  • given how important livestock are in the Maasai culture, it would make sense to continue to integrate conservation and livestock management more directly
61
Q

List ways in which human activities can affect populations

A
  • habitat destruction
  • competition for natural resources
  • hunting
  • pollution
62
Q

How can the effects of human activities be overcome

A
  • some areas are protected, such as national parks and 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
63
Q

Name 4 examples of where humans have strived to control their effects on the environment

A
  • The Galapagos Islands
  • The Antarctic
  • The Lake District
  • The Snowdonia national park
64
Q

Describe the species of the Galapagos islands

A
  • high numbers of native species incl. Darwin’s finches, giant tortoises, marine iguanas.
  • 50% of vertebrate species and 25% of plant species are endangered
  • The Galapagos human population has grown in response to increased demand for marine products and increased tourism
65
Q

Describe Habitat disturbance in the Galapagos Islands

A
  • population size increase- placed huge demands on water, energy and sanitation services
  • More waste and pollution have been produced
  • demand for oil has increased- an oil spill in 2001 had dramatic effect on marine and coastal ecosystems
  • Building and conversion of land for agriculture- caused destruction and fragmentation of habitats
  • Forests of Scalesia trees and shrubs (a species unique to the islands) have been almost eradicated on Santa Cruz and San Christobal, to make way for agricultural land
66
Q

Describe over-exploitation of resources in the Galapagos islands, what has been done to counter this

A
  • 19th century- whaling boats and fur traders killed 200 000 tortoises in less than half a century
  • The Charles Darwin Research Station has a captive breeding programme to supplement tortoise numbers
  • The more recent boom in fishing for exotic species has depleted populations
  • Depletion of sea cucumber populations has a drastic effect on underwater ecology
  • international market for shark fin has led to the deaths of 150000 sharks each year around the islands, including 14 endangered species
67
Q

Describe the effects of introduced species on the Galapagos islands

A
  • Alien species can out-compete local species, eat native species, destroy native species habitats, or bring disease onto the islands
  • Cats hunt a number of species, incl. the lava lizard and young iguanas
  • Goats feed on Galapagos rock-purslane (a species unique to the islands), and trample and feed upon giant tortoises’ food supply and disrupt their nesting sites
  • On northern Isabela Island, the goat has also transformed forest into grassland, leading to soil erosion
  • The red quinine is an aggressively invasive species on Santa Cruz Island- occupies the highlands, spreads rapidly- has wind-dispersed seeds
  • The ecosystem in the highlands has changed from low scrub and grassland, to a closed forest canopy because of this
  • the native Cacaotillo shrub has been almost eradicated from Santa Cruz and the Galapagos petrel has lost its nesting sites
  • The red quinine also successfully out-competes native Scalesia trees
68
Q

Describe the management of the effects of human activity in the Galapagos islands

A
  • 1999- the Charles Darwin Research Station adopted two strategies- to prevent the introduction and dispersion of introduced species and to treat the problems caused by such species
  • They search arriving boats and tourists for foreign species
  • Natural predators have also been exploited to reduce the damage caused to ecosystems by pest populations- e.g. controlled release of a ladybird wiped out
    a scale insect, which was damaging plant communities
  • Culling has also been successful against feral goats on Isabela Island and pigs on Santiago Island
69
Q

What is a challenge to conservation on the Galapagos islands

A
  • most residents were not born on the islands- fostering a culture of conservation and educating new arrivals about the islands is a challenge
70
Q

Describe an example of how stakeholders can work together to sustainably manage a resource on the Galapagos islands

A
  • The Galapagos marine reserve
  • The reserve is managed by the National Park Service, the Charles Darwin Research Station, and representatives of local fishermen, the tourist industry and naturalist guides
  • At least 36% of coastal zones have been designated ‘No-Take’ areas, where no extraction of resources is allowed, and communities are left undisturbed
70
Q

Describe an example of how stakeholders can work together to sustainably manage a resource on the Galapagos islands

A
  • The Galapagos marine reserve
  • The reserve is managed by the National Park Service, the Charles Darwin Research Station, and representatives of local fishermen, the tourist industry and naturalist guides
  • At least 36% of coastal zones have been designated ‘No-Take’ areas, where no extraction of resources is allowed, and communities are left undisturbed
71
Q

Name challenges to the Galapagos islands

A
  • Habitat disturbance
  • over-exploitation of resources
  • introduced species
72
Q

Describe the Antarctic

A
  • not governed by any one country, but countries have research stations there under the terms of the Antarctic Treaty
  • As such, the continent is relatively untouched by human influence,
    but with an increasing number of tourists and scientists, and with increased interest from the fishing industry, it remains important to actively protect the Antarctic ecosystem and biodiversity within it
73
Q

Name species needing protection in the Antarctic

A
  • krill
  • Albatrosses and petrels
74
Q

Nae a method of protection in the Antarctic

A

Protected areas

75
Q

Describe krill in the Antarctic

A
  • tiny shrimp-like organisms which provide food for whales, seals, penguins, albatrosses and squid
  • used to make nutritional supplements and for animal feed
  • Recent changes in technology mean that large amounts of krill can be harvested very quickly and easily
  • Fishing boats tend to congregate in those areas with the largest numbers of krill
  • However, natural predators of
    krill cannot adapt as easily to find krill elsewhere e.g. penguins do not migrate very far when raising young
  • To avoid over-exploitation, there is a trigger level catch size in particular areas
  • When reached, fishing must be conducted equally across all areas up to the total catch limit to avoid a catastrophic impact on predators
  • However, given the size of the krill fishery there are new recommendations to force the industry to fish evenly across all areas anyway
76
Q

Describe protected areas in the antarctic

A
  • To protect whales and the marine environment, a series of protected areas have been established
  • The Southern Ocean Whale Sanctuary- est. 1994- covers the summer feeding grounds Of 80—90% Of the world’s whales
  • This followed the 1982 moratorium on whaling established by the International Whaling Commission
  • Within the 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
  • Currently there is an initiative to expand a network of marine protected areas, such as in the Ross Sea (with its high biodiversity levels), which is already attracting the attention of the fishing industry
77
Q

Describe albatrosses and petrels in the Antarctic

A
  • these birds are threatened by human activities, including pollution, hunting and poaching for eggs, habitat destruction and introduction of non-native predators
    -However, the biggest threat
    is long-line fishing- when fishermen trail a long fishing line behind their boat (up to 130 km)- attached to this line are hundreds of baited hooks
  • When behind the boat, the birds try to eat the prey and swallow the hooks
  • To reduce the number of deaths, boats can use bird-scaring lines and
    streamers, weighted lines which sink more quickly out of reach of the birds, use lines at night to avoid albatross and petrel feeding times, and avoid breeding and nesting time
  • By implementing these methods, one Chilean fishery reduced its sea-bird catch to zero
78
Q

Describe the lake district and issues faced by it

A
  • contains an exceptionally rich diversity of species and habitats
  • The whole National Park is designated an Environmentally Sensitive Area
  • However, without grazing causing deflected succession, much of the land would revert to a climax community of oak woodland
  • Financial incentives are available for farmers to reduce chemical use, to safeguard hedges, and to care for hay
    meadows, heather moor, wetland, chalk downland and native woodland
79
Q

The lake district- table of threats and solutions

A
80
Q

Describe the Snowdonia national park

A
  • in North Wales, attracts walkers and climbers
  • On Mount Snowdon itself, good footpaths are maintained to ensure that rare plants are not trodden on
  • Gutters take water from the
    paths, but these can get blocked by rubbish dropped by walkers.
  • To prevent the path eroding, teams of workers clear the rubbish
  • National Park employees work with farmers to reduce sheep grazing on the mountain- asthey graze very low to the ground, they can leave the landscape very barren- Reducing sheep grazing gives the rare plants a better chance of survival
  • Feral goats are a problem for grazing, and their numbers and locations
    are monitored each year
  • Farmers are encouraged to plant hedges and conserve ancient woodland
  • As well as mountain habitat, there is also moorland and bog in Snowdonia- these habitats provide nesting sites for rare birds like the hen harrier, merlin and kestrel, and are home to a number of rare butterflies
  • Use of such wetland leads to humans having an impact upon it, which needs to be controlled
81
Q

Snowdonia- impacts of humans with solutions table

A
82
Q

Describe threats to woodlands

A
  • Easily converted to agricultural land
  • Development – housing
  • Logging; most trees are hardwoods, meaning they have a denser wood than most coniferous trees
  • Pollution - Acid Rain from coal-burning is another threat
  • Global warming - may change rainfall patterns
83
Q

List of benefits of coppicing

A

· new stems grow more rapidly than saplings
· lifespan of tree extended
· provides variety of light levels
· fewer large trees means more light for smaller plants
· provides a variety of habitats
· roots prevent soil erosion
· maintains soil quality
· prevents succession
· large machinery not needed

83
Q

List of benefits of coppicing

A

· new stems grow more rapidly than saplings
· lifespan of tree extended
· provides variety of light levels
· fewer large trees means more light for smaller plants
· provides a variety of habitats
· roots prevent soil erosion
· maintains soil quality
· prevents succession
· large machinery not needed

84
Q

Pros and cons of aquaculture

A

Module 6- Genetics and Ecosystems (6 decks)

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