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AS Biology Module 2 - Organisms and Biodiversity > Chapter 12 - Human Impact on Biodiversity > Flashcards

Chapter 12 - Human Impact on Biodiversity Flashcards

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1
Q

Biodiversity is a reflection of …

A

Both the number of species in an area and how evenly distributed the numbers of living organisms are spread across the range of species present.

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2
Q

Biodiversity is a reflection of both the number of species in an area and how evenly distributed the numbers of living organisms are spread across the range of species present. Agricultural practises can …

A

Significantly reduce biodiversity or help to promote biodiversity depending on the strategies used.

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3
Q

Biodiversity is a reflection of both the number of species in an area and how evenly distributed the numbers of living organisms are spread across the range of species present. Agricultural practises can significantly reduce biodiversity or help to promote biodiversity depending on the strategies used. Historically, in …

A

Highly developed countries such as Northern Ireland

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4
Q

Biodiversity is a reflection of both the number of species in an area and how evenly distributed the numbers of living organisms are spread across the range of species present. Agricultural practises can significantly reduce biodiversity or help to promote biodiversity depending on the strategies used. Historically, in highly developed countries such as Northern Ireland, the agricultural strategies that …

A

Maximise productivity and economic gain

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5
Q

Biodiversity is a reflection of both the number of species in an area and how evenly distributed the numbers of living organisms are spread across the range of species present. Agricultural practises can significantly reduce biodiversity or help to promote biodiversity depending on the strategies used. Historically, in highly developed countries such as Northern Ireland, the agricultural strategies that maximise productivity and economic gain have …

A

A serious impact on biodiversity.

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6
Q

What are intensive agricultural practices?

A

Intensive agricultural practices are those practices that are designed to maximise productivity (increased food production) and profit (economic gain).

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7
Q

Agricultural intensification in Northern Ireland has resulted in …

A

A very significant reduction in biodiversity

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8
Q

Agricultural intensification in Northern Ireland has resulted in a very significant reduction in biodiversity as a consequence of …

A

Habitat loss and habitat change

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9
Q

Name some agricultural practices that reduce biodiversity

A
  1. Increased use of monoculture.
  2. Nutrient enrichment of soils.
  3. Loss of hedgerow (and woodland).
  4. Increased use of pesticides.
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10
Q

Name some agricultural practices that promote biodiversity

A
  1. Polyculture.
  2. Increased use of organic fertiliser.
  3. Hedgerow conservation and maintenance.
  4. Integrated pest management and biological control
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11
Q

Why is increased use of monoculture an agricultural practice that reduces biodiversity?

A
  1. Whole areas of farmland are often given over to one species of crop, for example, barley or perennial ryegrass, the latter providing rich swards for silage or for grazing by cattle or sheep.
  2. Monoculture is a common practice on large farms due to the ‘economies of scale’ involved in ground preparation, planting and harvesting.
  3. However, as well as reducing biodiversity there are other problems with monoculture.
  4. These include the build-up of pests specific to the crop being grown and the fact that growing the same crop on the same land (year after year) can lead to the reduction of particular minerals in the soil because each successive crop has the same mineral ion requirements.

Note: the depletion of specific soil minerals with monoculture is exacerbated by the fact that the crop is invariably harvested before decay and decomposition can take place and return minerals to the soil.

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12
Q

Why is nutrient enrichment of soils an agricultural practice that reduces biodiversity?

A
  1. Monoculture is often associated with nutrient (particularly nitrate and phosphate) enrichment of soils in order to maximise crop yield.
  2. The use of artificial fertiliser, with high levels of nitrate, to encourage fast growth of a particular crop is particularly harmful to biodiversity, as it allows the target crop to outcompete and eliminate many other slower growing species.
  3. Nutrient enrichment is also used to maintain high stocking rates in livestock farming.
  4. It can also lead to loss of soil crumb structure, which can lead to increased soil erosion.
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13
Q

Why is loss of hedgerow (and woodland) an agricultural practice that reduces biodiversity?

A
  1. The loss of hedgerow and woodland, and its increasing fragmentation leads to loss of biodiversity through the loss of habitat and food for many hedgerow species.
  2. This in turn impacts adversely on other species, for example, those higher up in the food chain.
  3. As well as being habitats in their own right, hedgerows act as wildlife ‘corridors’, linking areas of woodland or other species-rich habitats.
  4. These ‘corridors’ facilitate the movement and dispersal of many species, including small mammals, birds, amphibians and insects, such as butterflies.
  5. Removal of hedgerows can occur for many reasons, for example, increasing the area of land available for agriculture and facilitating the use of larger agricultural machinery (which is often associated with monocultures).
  6. Hedgerow loss can also lead to more soil erosion due to the land being more exposed to wind and rain, and the reduction of the soil binding role of tree and shrub roots.
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14
Q

Why is increased use of pesticides an agricultural practice that reduces biodiversity?

A
  1. Pesticides are used to maximise crop production through eliminating pests that reduce production.
  2. Broad spectrum pesticides (insecticides) can reduce biodiversity by killing organisms of species other than the intended target.
  3. They kill many of the soil organisms that are involved in decomposition and improving soil structure.
  4. In addition, the pesticide can eliminate natural predators of the main pest and cause pest resurgence, allowing the pest to return in even greater numbers.
  5. The use of herbicides (a particular type of pesticide used to eliminate weeds/competitor plant species) both reduces plant biodiversity (as it eliminates non-crop species) and reduces the variety of food available to a variety of animal species, thereby reducing animal species diversity.
  6. Some species can become resistant to pesticides and there can be issues with bioaccumulation (the build-up of concentrations in the tissues of organisms at progressively higher tropic levels).
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15
Q

What is a pest species?

A

A species that damages a valuable/commercial crop species, causing economic damage

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16
Q

Why is polyculture an agricultural practice that promotes biodiversity?

A
  1. This is the growing of a range of different at the one time or sequentially in the one place.
  2. There are many advantages with polyculture, including the provision of a wider range of food sources and habitats for wildlife.
  3. This in turn leads to a greater number of, and more complex, food webs.
  4. Crop rotation is a particular type of polyculture.
  5. It is the planting of different crops in the same field over a period of years.
  6. Crop rotation helps conserve soil fertility as the different crops (for example, wheat and turnip) make different demands on soil nutrients.
  7. Crop rotation can be particularly effective in improving soil fertility when nitrogen-fixing crops, such as peas, beans and clover, are part of the cycle.
  8. Crop rotation also reduces the likelihood of a build-up of pests specific to one crop in an area.
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17
Q

Why is increased use of organic fertiliser an agricultural practice that promotes biodiversity?

A
  1. The use of organic fertiliser (farmyard manure) and the consequent decreases in the use of artificial (bagged) fertiliser also helps to promote soil fertility.
  2. This helps preserve soil crumb structure as the humus in the farmyard manure holds the crumb structure together.
  3. Farmyard manure also releases nutrients at a slower rate with less mineral loss due to leaching, as the plants can make better use of a greater proportion of the more slowly released nutrients.
  4. Organic fertiliser is more difficult to store and spread than artificial fertiliser and its nutrient content is more variable.
  5. Artificial fertiliser still has its role but there is now a greater awareness of the need to match mineral content of the fertiliser used to the specific nutrient needs of the crop being grown.
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18
Q

Why is hedgerow conservation and maintenance an agricultural practice that promotes biodiversity?

A
  1. The planting of new hedgerows and the restoration and maintenance of existing ones help support biodiversity.
  2. Hedgerows most likely to encourage biodiversity are those that contain a range of shrub and tree species, which in turn provide a range of different habitats and food sources for birds and other animals.
  3. Biodiversity-friendly hedgerow trimming will further increase biodiversity through:
    • Allowing hedgerow trees to grow to maturity at intervals in the hedge.
    • Only trimming on a 2-3 year rotation. This allows shrubs to flower and produce berries, providing food for birds over the winter months.
    • Trimming during late winter (January-February) to avoid the destruction of bird nests during the spring and summer, and allowing berries to develop in the autumn, again providing food for birds.
    • Maintaining a range of hedge heights and widths by staggering trimming regimes. This maintains a wide range of habitats. For example, different bird species have different preferences for hedgerow heights and width. Hedges cut in an ‘A’ shape, as opposed to box shape, can be particularly diverse as this allows more light to penetrate to ground level.
  4. When establishing a new hedgerow, or carrying out substantial repairs to an existing one, it is important to protect the young hedgerow trees/shrubs from grazing.
  5. This can be done by planting the hedge between a double fence, which both protects the young hedge and forms an effective boundary in the interim.
  6. In due course the fence can be removed.
  7. It is also important to plant a mixture of woody species in a new hedge with associated biodiversity benefits, ie avoid a monoculture of hawthorn.
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19
Q

Biodiversity-friendly hedgerow trimming will further increase biodiversity through:

A
  • Allowing hedgerow trees to grow to maturity at intervals in the hedge.
  • Only trimming on a 2-3 year rotation. This allows shrubs to flower and produce berries, providing food for birds over the winter months.
  • Trimming during late winter (January-February) to avoid the destruction of bird nests during the spring and summer, and allowing berries to develop in the autumn, again providing food for birds.
  • Maintaining a range of hedge heights and widths by staggering trimming regimes. This maintains a wide range of habitats. For example, different bird species have different preferences for hedgerow heights and width. Hedges cut in an ‘A’ shape, as opposed to box shape, can be particularly diverse as this allows more light to penetrate to ground level.
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20
Q

Why is integrated pest management and biological control an agricultural practice that promotes biodiversity?

A
  1. Broad spectrum pesticides have been widely used in the past and these have proved to be detrimental to biodiversity.
  2. They may kill many of the target pests but also eliminate the natural predators of the pest and kill soil organisms important in the decomposition of organic matter and the maintenance of soil fertility.
  3. More integrated pest management approaches are now being encouraged, which include the use of narrow-spectrum pesticides that only affect the target pest species.
  4. Additionally, strategies such as crop rotation help prevent the build-up of large pest populations, as the absence of a specific crop for a few years may prevent the pest being able to complete its life cycle.
  5. Biological control can also be used as an alternative to pesticide use.
  6. Biological control will benefit the environment by reducing the need for chemical pesticides and also because broad-spectrum pesticides often do not work very well.
  7. The graph below shows that a pest can experience pest resurgence in that its numbers increase rapidly due to the elimination of a natural predator. (Textbook page 212).
  8. The graph below shows how effective biological control can reduce pest numbers below the threshold of economic damage.
  9. With effective biological control, the introduced predator integrates naturally into the ecosystem, building a sustainable population and therefore does not need to be continually re-introduced.
  10. Effective biological control possesses the following advantages:
    • There is no chemical damage to the environment with the risk of significant ecological harm and bioaccumulation in food chains.
    • Biological control targets only the pest species - there is reduced collateral damage affecting other organisms.
    • The development of resistance by the pests is unlikely.
    • Pest resurgence is unlikely.
    • Biological control, if successful, needs little additional action and saves money on the continued use of pesticides.

Note: insect populations treated with insecticides frequently develop resistance to the pesticide and it ceases to become effective. Before the pesticide is applied, a small number of individuals in a population will have resistance due to mutation. However, when the pesticide is used, the non-resistant individuals are killed leaving only the resistant individuals (that survive and reproduce), resulting in the population becoming resistant.

  1. The development of predator strips (small areas of rough grass left undisturbed at field hedges) will encourage the increase in numbers of many crop pests’ natural predators on the farmland.
  2. Carabid beetles and ladybirds can thrive in relatively species-rich predator strips (undisturbed through the absence of harmful fertiliser or pesticides) and feed on the harmful aphids that damage the crop.
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21
Q

What is biological control?

A

Biological control involves deliberately introducing predator (or parasitic or pathogenic) species that target the pest.

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22
Q

What are the disadvantages of biological control?

A
  1. Biological control has its limitations and is not always successful.
  2. For example, the pest will not be totally eliminated - its density is reduced (ideally to below the threshold of economic damage).
  3. Biological control will only work well if the biological control species can adapt and thrive in the ecosystem into which it is introduced - often an ‘unnatural’ crop ecosystem not found in the wild can be hostile to the introduced biological control species.
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23
Q

What are predator strips?

A

Small areas of rough grass left undisturbed at field hedges.

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24
Q

What are the advantages of effective biological control?

A
  • There is no chemical damage to the environment with the risk of significant ecological harm and bioaccumulation in food chains.
  • Biological control targets only the pest species - there is reduced collateral damage affecting other organisms.
  • The development of resistance by the pests is unlikely.
  • Pest resurgence is unlikely.
  • Biological control, if successful, needs little additional action and saves money on the continued use of pesticides.
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25
Q

Inappropriate farming practices can also …

A

Harm the environment and reduce biodiversity in a number of other ways

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26
Q

Inappropriate farming practices can also harm the environment and reduce biodiversity in a number of other ways, including …

A

The pollution of waterways.

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27
Q
  • The pollution of waterways

Waterways, including …

A

Oceans, seas, lakes and rivers

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28
Q
  • The pollution of waterways

Waterways (oceans, seas, lakes and rivers) have been subject to …

A

Pollution for centuries due to human activity.

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29
Q
  • The pollution of waterways
    Waterways (oceans, seas, lakes and rivers) have been subject to pollution for centuries due to human activity. Increased …
A

Urbanisation

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30
Q
  • The pollution of waterways
    Waterways (oceans, seas, lakes and rivers) have been subject to pollution for centuries due to human activity. Increased urbanisation, particularly in …
A

The developing world

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31
Q
  • The pollution of waterways
    Waterways (oceans, seas, lakes and rivers) have been subject to pollution for centuries due to human activity. Increased urbanisation, particularly in the developing world, often results in …
A

Poor sanitation levels

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32
Q
  • The pollution of waterways
    Waterways (oceans, seas, lakes and rivers) have been subject to pollution for centuries due to human activity. Increased urbanisation, particularly in the developing world, often results in poor sanitation. This, combined with …
A

Increasing amounts of industrial waste

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33
Q
  • The pollution of waterways
    Waterways (oceans, seas, lakes and rivers) have been subject to pollution for centuries due to human activity. Increased urbanisation, particularly in the developing world, often results in poor sanitation. This, combined with increasing amounts of industrial waste, has resulted in …
A

Many of the world’s rivers being polluted to the extent that very little life more complex than prokaryotes and protoctistans can survive.

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34
Q
  • The pollution of waterways
    Waterways (oceans, seas, lakes and rivers) have been subject to pollution for centuries due to human activity. Increased urbanisation, particularly in the developing world, often results in poor sanitation. This, combined with increasing amounts of industrial waste, has resulted in many of the world’s rivers being polluted to the extent that very little life more complex than prokaryotes and protoctistans can survive.

In Northern Ireland, …

A

Sanitation standards are high and industrial pollution has been much reduced in recent decades.

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35
Q
  • The pollution of waterways
    Waterways (oceans, seas, lakes and rivers) have been subject to pollution for centuries due to human activity. Increased urbanisation, particularly in the developing world, often results in poor sanitation. This, combined with increasing amounts of industrial waste, has resulted in many of the world’s rivers being polluted to the extent that very little life more complex than prokaryotes and protoctistans can survive.

In Northern Ireland, sanitation standards are high and industrial pollution has been much reduced in recent decades. Consequently, …

A

Much of the pollution affecting out waterways at the start of the twenty-first century is agricultural-related.

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36
Q

Name two causes of water pollution

A

Organic pollution

Eutrophication

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37
Q

What is organic pollution?

A

The pollution of water by organic material.

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38
Q

Name some organic pollutants

A

Sewage
Slurry
Silage effluent

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39
Q

What happens if organic pollutants enter waterways?

A
  • If organic pollutants enter waterways they provide a rich source of nutrients for bacteria involved in the decay process.
  • The rich organic food supply results in a population explosion of saprobiotic bacteria that subsequently use up much of the oxygen in the water due to aerobic respiration.
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40
Q

What does BOD stand for?

A

Biological oxygen demand

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41
Q

What is the biological oxygen demand (BOD)?

A

The biological oxygen demand (BOD) is an indication of water quality, measured as the usage of oxygen in the water.

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42
Q

The biological oxygen demand (BOD) is an indication of water quality, measured as the usage of oxygen in the water. High levels of …

A

Organic substances in the water

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43
Q

The biological oxygen demand (BOD) is an indication of water quality, measured as the usage of oxygen in the water. High levels of organic substances in the water will lead to …

A

More bacteria

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44
Q

The biological oxygen demand (BOD) is an indication of water quality, measured as the usage of oxygen in the water. High levels of organic substances in the water will lead to more bacteria, therefore …

A

More aerobic respiration

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45
Q

The biological oxygen demand (BOD) is an indication of water quality, measured as the usage of oxygen in the water. High levels of organic substances in the water will lead to more bacteria, therefore more aerobic respiration and therefore …

A

Higher BODs and vice versa.

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46
Q

The biological oxygen demand (BOD) is an indication of water quality, measured as the usage of oxygen in the water. High levels of organic substances in the water will lead to what?

A

More bacteria, therefore more aerobic respiration and therefore higher BODs and vice versa.

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47
Q

Silage effluent has a very (blank) BOD

A

High

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48
Q

Silage effluent has a very high BOD (about 65,000 mg/l). Milk has …

A

An even higher value

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49
Q

Silage effluent has a very high BOD (about 65,000 mg/l). Milk has an even higher value (about 140,000 mg/l). Why is this?

A

As milk is a high energy organic food for mammals, animals that have high metabolic needs.

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50
Q

Often organic pollution occurs …

A

As isolated and specific events

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51
Q

Often organic pollution occurs as isolated and specific events. An example is …

A

Sewage entering waterways as a result of flooding affecting the sewage system or from a slurry tank leak.

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52
Q

Draw a graph showing the changes in BOD and water oxygen levels in a waterway after an incident of organic pollution

A

Textbook page 214

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53
Q

What is eutrophication?

A

The (gradual and long term) nutrient enrichment of waterways, in particular nitrates and phosphates (as opposed to an organic pollution incident).

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54
Q

Under natural conditions, eutrophication is …

A

Not a problem as the amount of nutrient naturally entering waterways is very low and has little effect on aquatic ecosystems.

55
Q

Nutrient enrichment, as a consequence of …

A

Farming activities

56
Q

Nutrient enrichment, as a consequence of farming activities, has been a significant problem in …

A

Northern Ireland and other intensively farmed countries.

57
Q

Nutrient enrichment, as a consequence of farming activities, has been a significant problem in Northern Ireland and other intensively farmed countries. Much of the nutrient enrichment comes from …

A

The nitrate and phosphate in artificial fertilisers.

58
Q

How does the nitrate and phosphate in artificial fertilisers enter the waterways, causing nutrient enrichment?

A

If too much fertiliser is applied, or it is applied on sloping ground too close to waterways or applied in wet conditions, the nitrate and phosphate can leach through the soil into the water.

59
Q

Nutrient enrichment, as a consequence of farming activities, has been a significant problem in Northern Ireland and other intensively farmed countries. Much of the nutrient enrichment comes from the nitrate and phosphate in artificial fertilisers. If too much fertiliser is applied, or it is applied on sloping ground too close to waterways or applied in wet conditions, the nitrate and phosphate can leach through the soil into the water. When this …

A

Happens in large enough quantities

60
Q

Nutrient enrichment, as a consequence of farming activities, has been a significant problem in Northern Ireland and other intensively farmed countries. Much of the nutrient enrichment comes from the nitrate and phosphate in artificial fertilisers. If too much fertiliser is applied, or it is applied on sloping ground too close to waterways or applied in wet conditions, the nitrate and phosphate can leach through the soil into the water. When this happens in large enough quantities the following sequence typically results:

A
  1. The increased nitrate and phosphate causes a very large increase in algal growth - known as algal blooms. (Under ‘normal’ non-enriched conditions the levels of nitrate and phosphate in lakes and rivers limit algal growth).
  2. The rapid and extensive growth of the dense algal blooms (found in highest amounts on the surface of the water) prevent light penetrating through the water to the plants at lower levels. The algae also deplete the water of nutrients.
  3. These plants die due to a shortage of light (or nutrients) and are decomposed by saprophytic bacteria.
  4. The bacteria use up the oxygen in aerobic respiration.
  5. The shortage of oxygen results in the death of many species of invertebrates and fish, and a consequent loss of biodiversity.

The algae is blue-green algae (cyanobacteria).

61
Q

Name a substance ,other than artificial fertiliser, which causes eutrophication

A

Washing powder (containing phosphate)

62
Q

Why is phosphate pollution from washing powder no longer a significant cause of eutrophication?

A

Due to the development of phosphate-free detergents and more efficient filtering systems in sewage works

63
Q

Before phosphate-free detergents and the development of more efficient filtering systems in sewage works, phosphate pollution from …

A

Washing powder was a significant cause of eutrophication.

64
Q

Before phosphate-free detergents and the development of more efficient filtering systems in sewage works, phosphate pollution from washing powder was a significant cause of eutrophication. This was a factor in …

A

The original development of Lough Neagh as a highly eutrophic lake

65
Q

Before phosphate-free detergents and the development of more efficient filtering systems in sewage works, phosphate pollution from washing powder was a significant cause of eutrophication. This was a factor in the development of Lough Neagh as a highly eutrophic lake (the leaching of phosphate and nitrate from …

A

Agricultural land has been a more important factors in recent decades.

66
Q

Reducing eutrophication of waterways - The main objective has been to …

A

Reduce the leaching of nitrate and phosphate into waterways

67
Q

Reducing eutrophication of waterways - The main objective has been to reduce the leaching of nitrate and phosphate into waterways, and many of the measures taken are linked to …

A

European legislation

68
Q

Reducing eutrophication of waterways - The main objective has been to reduce the leaching of nitrate and phosphate into waterways, and many of the measures taken are linked to European legislation, for example …

A

The European Nitrates Directive

69
Q

Reducing eutrophication of waterways - The main objective has been to reduce the leaching of nitrate and phosphate into waterways, and many of the measures taken are linked to European legislation (for example, the European Nitrates Directive). These strategies include:

A
  1. Testing the mineral ion content of soil before application of fertiliser.
    - This will ensure that only the correct amount of fertiliser is used and that the balance of nutrients (for example, nitrate and phosphate) is appropriate for the crop’s needs.
  2. Only applying the fertiliser immediately prior to or during periods of crop growth, ie the need for ‘closed periods’ at certain times of the year when it is not beneficial or appropriate to apply fertiliser.
    - This ensures that the nutrients are not in excess and do not get a chance to build up in the soil with the subsequent risk of leaching into surrounding waterways.
  3. Not applying fertiliser when heavy rain is forecast.
  4. Not applying fertiliser on land that is close to waterways (this can be a particular issue if the land is sloping).
  5. The requirement to have adequate storage facilities for slurry and other farm wastes that can cause water enrichment.
  6. Government guidelines at both European (for example, the Nitrates Directive) and local levels (DAERA NI Code of Good Agricultural Practice) provide both legislation and guidelines aimed at reducing eutrophication and the encouragement of conservation in agricultural settings in general.
70
Q
  • Other initiatives to conserve habitats and promote biodiversity

The protection and conservation of specific habitats are supported through:

(Name the initiatives)

A
  1. Areas of Specific Scientific Interest (ASSI)
  2. Special Areas of Conservation (SACs)
  3. Biodiversity Action Plans
  4. Department of Agriculture, Environment and Rural Affairs (DAERA) agri-environment schemes
  5. Northern Ireland priority habitat and species list
71
Q

What are Areas of Specific Scientific Interest (ASSI)?

A
  • These are ecologically important areas with high conservation value that are managed in cooperation with the landowners.
  • In Northern Ireland there are over 200 ASSIs, ranging in size from large expanses of water and their shores (for example, Lough Neagh), to small areas of woodland or grassland.
  • In general, the plan is that the ASSIs are managed in a way to promote biodiversity.
72
Q

What are Special Areas of Conservation (SACs)?

A
  • These areas are given special protective status under the EU Habitats Directive to conserve threatened species and habitats.
  • There are over 50 SACs in Northern Ireland, which are protected to conserve threatened habitats and/or the species they contain.
  • For example, Rathlin Island has a SAC status in an attempt to conserve the reefs, vegetated sea cliffs and the sea caves around its coast, and the rare endangered species they contain.
73
Q

What are Biodiversity Action Plans?

A
  • These involve policies and activities organised at a local council level in Northern Ireland.
  • They involve local initiatives including meetings, activities (for example, hedgerow planting), the production of leaflets promoting biodiversity and projects in conjunction with other conservation groups such as Ulster Wildlife.
74
Q

What are DAERA agri-environment schemes?

A
  • These schemes provide financial and other support to farmers and landowners with the aim of supporting biodiversity and conservation in areas such as maintaining rare habitats, improving water quality and the removal of harmful weeds and invasive plants.
75
Q

What is the Northern Ireland priority habitat and species list?

A
  • The Wildlife and Natural Environment Act (Northern Ireland) requires the DAERA to identify priority habitats and species which are most important from a conservation and biodiversity perspective.
  • This is to assist those bodies involved in conservation and biodiversity, and other bodies that impact on the environment (for example, Council Planning Departments).
  • Habitats that have been identified include blanket bogs and estuaries.
  • There are nearly 500 species that have been identified, including the very rare corncrake and the frog orchid as well as some more common species.
76
Q
  • Global warming and climate change

Global warming and associated climate change also affect …

A

Biodiversity.

77
Q
  • Global warming and climate change

Global warming and associated climate change also affect biodiversity. For millions of years the carbon cycle has …

A

Remained relatively balanced with the carbon dioxide removed from the atmosphere in photosynthesise being approximately the same as the carbon dioxide added in respiration (and relatively small scale combustion).

78
Q
  • Global warming and climate change

Global warming and associated climate change also affect biodiversity. For millions of years the carbon cycle has remained relatively balanced with the carbon dioxide removed from the atmosphere in photosynthesise being approximately the same as the carbon dioxide added in respiration (and relatively small scale combustion). However, since …

A

The industrial revolution two major changes have taken place.

79
Q
  • Global warming and climate change

Global warming and associated climate change also affect biodiversity. For millions of years the carbon cycle has remained relatively balanced with the carbon dioxide removed from the atmosphere in photosynthesise being approximately the same as the carbon dioxide added in respiration (and relatively small scale combustion). However, since the industrial revolution two major changes have taken place:

A
  • Increased combustion of fossil fuels has added much more carbon dioxide into the atmosphere.
  • Deforestation on a major scale to create land for farming, industry or urban development has reduced the amount of photosynthesis taking place and consequently the removal of carbon dioxide from the atmosphere.
80
Q
  • Global warming and climate change

Global warming and associated climate change also affect biodiversity. For millions of years the carbon cycle has remained relatively balanced with the carbon dioxide removed from the atmosphere in photosynthesise being approximately the same as the carbon dioxide added in respiration (and relatively small scale combustion). However, since the industrial revolution two major changes have taken place:

  • Increased combustion of fossil fuels has added much more carbon dioxide into the atmosphere.
  • Deforestation on a major scale to create land for farming, industry or urban development has reduced the amount of photosynthesis taking place and consequently the removal of carbon dioxide from the atmosphere.

These changes have …

A

Resulted in the carbon cycle becoming unbalanced and the concentrations of carbon dioxide in the atmosphere have increased as a result.

81
Q
  • The link between increasing carbon dioxide and global warming
    There is clear evidence that atmospheric …
A

Carbon dioxide levels are increasing.

82
Q
  • The link between increasing carbon dioxide and global warming
    There is clear evidence that atmospheric carbon dioxide levels are increasing. What is the carbon dioxide level of the atmosphere today?
A

Approximately 390 parts per million (ppm)

83
Q
  • The link between increasing carbon dioxide and global warming
    There is clear evidence that atmospheric carbon dioxide levels are increasing. What was the carbon dioxide level of the atmosphere 200 years ago?
A

Under 300 parts per million (ppm)

84
Q
  • The link between increasing carbon dioxide and global warming
    There is clear evidence that atmospheric carbon dioxide levels are increasing. Carbon dioxide levels in the atmosphere are approximately 390 parts per million (ppm) today compared with a level of under 300 ppm 200 years ago, an increase of around …
A

30%

85
Q
  • The link between increasing carbon dioxide and global warming
    There is clear evidence that atmospheric carbon dioxide levels are increasing. Carbon dioxide levels in the atmosphere are approximately 390 parts per million (ppm) today compared with a level of under 300 ppm 200 years ago, an increase of around 30%. In some parts of the world the increase in average temperature has …
A

Exceeded 2°C over the last 100 years

86
Q
  • The link between increasing carbon dioxide and global warming
    There is clear evidence that atmospheric carbon dioxide levels are increasing. Carbon dioxide levels in the atmosphere are approximately 390 parts per million (ppm) today compared with a level of under 300 ppm 200 years ago, an increase of around 30%. In some parts of the world the increase in average temperature has exceeded 2°C over the last 100 years. Furthermore, …
A

The rate of increase is increasing and is now almost 0.2°C per decade.

87
Q

Describe the relationship between carbon dioxide levels and global temperature

A

There is clear evidence that there is a close positive correlation between increasing carbon dioxide and global temperature

88
Q

There is clear evidence that there is a close positive correlation between increasing carbon dioxide and global temperature. Where the debate lies is …

A

Whether the increase in carbon dioxide level is the only, or major, cause of increasing atmospheric temperatures.

89
Q

Carbon dioxide is a …

A

Greenhouse gas

90
Q

There is clear evidence that there is a close positive correlation between increasing carbon dioxide and global temperature. Where the debate lies is whether the increase in carbon dioxide level is the only, or major, cause of increasing atmospheric temperatures. There is no doubt that carbon dioxide is a …

A

Greenhouse gas

91
Q

There is clear evidence that there is a close positive correlation between increasing carbon dioxide and global temperature. Where the debate lies is whether the increase in carbon dioxide level is the only, or major, cause of increasing atmospheric temperatures. There is no doubt that carbon dioxide is a greenhouse gas. Consequently, most of the scientific community believe that …

A

Increasing carbon dioxide levels are the main cause of global warming.

92
Q

Draw a graph showing atmospheric carbon dioxide levels from 1970 to 2010

A

Textbook page 217

93
Q

The graph on page 217 of the textbook shows how the atmospheric carbon dioxide levels are rising. What do the annual fluctuations reflect?

A

The annual fluctuations reflect the higher winter carbon dioxide levels (compared to summer) due to reduced photosynthesis and increased combustion of fossil fuels for heating.

94
Q

What mechanism is the cause of global warming?

A

The greenhouse effect

95
Q

What is the greenhouse effect?

A
  1. The greenhouse effect: the cause of global warming.
  2. Carbon dioxide and other greenhouse gases form a layer (the greenhouse layer) in the atmosphere that traps heat.
  3. Relatively short(er) wave solar radiation (mainly visible light and ultraviolet (UV) radiation) reaches the Earth’s surface.
  4. However, the radiation emitted from the Earth into the atmosphere is long(er) wave (infrared) radiation (heat).
  5. Some of this longer wave radiation escapes the Earth’s atmosphere and enters Space but some is trapped by the greenhouse layer, reflected back and retained in the Earth’s atmosphere.
  6. This reflected and retained heat results in the atmospheric temperatures rising.
96
Q

Draw a diagram showing the greenhouse effect

A

Textbook page 218

97
Q

Why is a greenhouse effect necessary?

A
  • The greenhouse effect is a natural process that is necessary to sustain life as we know it.
  • Without a greenhouse effect the average temperature at the Earth’s surface would fall to -18°C.
  • The problem is that the ability of the greenhouse layer to trap heat energy has increased.
98
Q

What percentage of global warming is carbon dioxide responsible for?

A

60-70%

99
Q

Name some greenhouse gases

A 
Carbon dioxide (CO2)
Methane (CH4)
Nitrous oxide (N2O)
100
Q

What are some of the effects of global warming?

A
  1. The melting of the ice caps in polar regions is an obvious consequence that is being monitored in detail.
  2. This has the effect of raising sea levels with the risk of the flooding of many lowland areas such as Holland, Bangladesh and even parts of Britain including East Anglia.
  3. In the summer of 2012, the extent of the Arctic ice cap had shrunk to its smallest ever size (the previous smallest extent was in 2007).
  4. The shrinkage is exacerbated by the fact that the ice is also getting thinner.
  5. The average thickness of the polar ice was only about 1.5 m in summer 2012, whereas 20 years earlier it was close to 4 m in thickness - reduction in volume of around 70%.
  6. The extra water in the oceans is likely to disrupt ocean currents.
  7. Britain would be adversely affected if the Gulf Stream current brining warmer water across the Atlantic was pushed further north.

Note: the higher global temperatures will also make the water in the oceans expand. Some scientists believe that this might have as much an effect on sea levels as melting ice caps.

  1. Changing climates are another consequence of global warming. The meteorological data for the British Isles shows that in recent years, summers are getting warmer and wetter.
101
Q

How will global warming and climate change affect ecosystems?

A
  1. The distribution of many plant and animal species change as the temperatures change.
  2. In the British Isles this could mean the loss of some of our more northerly species but also the introduction of some species that currently do not extend as far north as the British Isles. (ie The distribution of species will shift northwards or to higher altitudes).
  3. Global warming could lead to the introduction into Britain of the heat-requiring mosquito (and its malarial parasite), a change that would have potentially deadly consequences.
  4. Global warming can also affect biodiversity through changing habitats.
  5. It can lead to increased desertification (in already very warm areas), but also increased flooding.
  6. It is also important to remember that if climate change affects any one species in a food web (perhaps because this species is at the limits of its ecological range anyway), then other species in the food web can be affected.
  7. There are many other ways in which biodiversity can be affected, for example, the more rapid spread of disease in warmer climates.
  8. It is thought that perhaps as many as one in ten species are at risk of extinction over the next few decades as a result of global warming.
  9. Obviously species that are already rare or endangered are at greatest risk and of course the harm that climate change causes is not acting in isolation; it is operating in tandem with habitat fragmentation and destruction and other harmful agricultural practices.
  10. The acidification of the oceans (CO2 is acidic and very soluble in water) is a threat to coral reef ecosystems.
102
Q

Knowledge check 49

What are the advantages of crop rotation? What are the disadvantages?

A

Advantages: reduced need for fertiliser (because soil fertility is maintained) and pesticides (because build-up of pests is prevented).
Disadvantages: reduced profitability through higher labour costs and greater diversity of machinery required.

103
Q

Knowledge check 50

Why is the annual cutting of hedgerow detrimental to biodiversity?

A

Only a few species are adapted to a habitat of short, well-trimmed hedges. A variety of hedge heights and thicknesses, resulting from a 3-year rotation of hedge trimming, will favour a greater biodiversity because some species will be adapted to conditions in tall, wide hedges while others will be adapted to short, narrow hedges.

104
Q

Knowledge check 51
Suggest how Simpson’s diversity index for a mixed woodland of native trees would compare with that for a conifer plantation.

A

Simpson’s diversity index, D, would be lower for the mixed woodland than for the conifer plantation.

105
Q

Knowledge check 52

Why might the use of pesticides be ineffective in controlling the numbers of pest species?

A

This is because of pest resistance, pest resurgence and secondary pest outbreak.

106
Q

Knowledge check 53
Where discharge of organic matter into waterways is unavoidable (e.g. from septic tanks), reed beds may be constructed at the point of discharge. The common reed has the ability to transfer oxygen from its leaves down through its stem, and out via its root system. Suggest why reed beds are useful in dealing with minor discharges of organic matter.

A

The high levels of oxygen released support a large bacterial population capable of digesting organic matter in the discharge, as long as the latter is not excessive.

107
Q

Knowledge check 54
Suggest one reason why consequences of eutrophication are:
a) more likely to occur in warm water
b) less likely to occur in moving water than in still water

A

a) Higher temperatures stimulate algal growth (increasing enzyme activity and algal metabolism).
b) Movement of the water (e.g. tumbling over rocks) re-oxygenates the water.

108
Q

Knowledge check 55

Explain why organic fertilisers release nutrients over a longer period of time than do inorganic fertilisers.

A

Organic matter needs to be broken down - by soil bacteria and fungi - to release nutrients, and this takes place over time.

109
Q

Knowledge check 56

Why is it important to protect habitats as well as individual species?

A

To protect any individual species (such as an orchid) it is necessary to protect its habitat; and, more importantly, it is likely to be the whole community of plants and animals in the habitat that needs protection.

110
Q

Knowledge check 57

What aspects of biodiversity should be considered in any Biodiversity Action Plan?

A

Species diversity, genetic diversity within species, ecosystem diversity

111
Q

Knowledge check 58

Explain how the use of fertilisers can lead to a loss of biodiversity.

A

It leads to nutrient enrichment of the soil, which selects rapid-growth grass species. These outcompete plant species that are adapted to nutrient-poor soils, which therefore results in a loss of biodiversity.

112
Q

Knowledge check 59

Permafrost contains a large amount of frozen organic matter. What are the consequences of the permafrost thawing?

A

As permafrost thaws, bacteria within the soil will become active, feed on the organic matter and through their respiration release large amounts of CO2 and methane into the atmosphere. This will result in a projected global warming of 0.13-1.69°C by 2020.

113
Q

Knowledge check 60
Temperature rises in the UK could create and environment suitable for mosquitos previously confined to Africa. What health problems would be associated with an invasion of these mosquitoes?

A

Some of these mosquitoes are vectors for a number of tropical diseases, including malaria.

114
Q

Knowledge check 61

Explain the rise in carbon dioxide levels in the atmosphere.

A

The rise in carbon dioxide levels is caused by combustion of fossil fuels and deforestation.

115
Q

What is intensive farming?

A

The growing of high-yield, single-species crops, using fertilisers and pesticides to maximise productivity.

116
Q

What is inorganic fertiliser?

A

A chemical (artificial or synthetic) fertiliser that releases ions quickly into the soil (compared with organic fertilisers, such as manure, which releases nutrients more slowly as they decompose).

117
Q

What is permafrost?

A

Subsoil that remains below freezing point throughout the year, occurring chiefly in polar regions.

118
Q

Why is thawing of arctic permafrost an important issue?

A

As permafrost thaws, bacteria become active, decomposing organic matter in the soil and contributing large amounts of CO2 and methane to the atmosphere - further increasing global warming.

119
Q

Why does methane contribute less to the greenhouse effect and global warming compared to carbon dioxide?

A

Methane is almost 30 times more potent as a greenhouse gas than CO2, though as its concentration is much lower, and it is shorter lasting in the atmosphere than CO2, its overall effect is less.

120
Q

What are the advantages of crop rotation?

A
  1. There is increased soil fertility, because different plant species have different nutrient demands.
  2. It becomes harder for pests and pathogens to become established, because the same crop species is not grown continuously.
121
Q

What are the advantages and disadvantages of polyculture?

A
  1. Pests and pathogens are unable to spread through the entire crop because different species are grown, and so pest control is easier.
  2. There is increased soil fertility, because different plant species have different nutrient demands.
  3. Species diversity is supported

However, labour costs are greatly increased through planting, harvesting and marketing different crops within the same year.

122
Q

How does good hedgerow management through trimming aim to promote biodiversity?

A
  1. Maintain a variety of hedge heights and widths to provide the optimum range of habitats (different bird species have different preferences).
  2. Trim in January/February to avoid destruction of birds’ nests (March-August) and allow the berry crop to be used by wintering birds (September-December).
  3. Trim on a 2- or 3-year rotation rather than annually, to boost the berry crop and insect populations and thereby bird populations.
  4. Avoid trimming all hedges in the same year (to allow hedge diversity).
  5. Avoid cutting native hedgerow trees as these support a greater range of insect and bird species.
123
Q

Crops that are susceptible to pests and diseases may require …

A

The application of pesticides: herbicides, insecticides and fungicides.

124
Q

What are the disadvantages of broad spectrum (indiscriminate) pesticides?

A

Indiscriminate pesticide use has been found to be problematic both in terms of its negative effect on biodiversity and its long-term effectiveness

  1. Pests have rapid rates of population growth, so resistant strains tend to evolve.
  2. Pesticides may be toxic to species other than the pest species (these are ‘broad-spectrum’ pesticides), leading to:
    - Pest resurgence - greater numbers of pests return because a natural predator is killed.
    - Secondary pest outbreak - a minor pest multiplies rapidly in the absence of its competitor.
  3. Pesticides may persist in the environment and adversely affect other ecosystems, for example herbicide spray may drift into adjacent areas and kill plant species important in the food chains of various animals.
  4. Persistent pesticides may also be non-biodegradable (not broken down in animal tissues), so there is a build-up along the food chain, a phenomenon called bioaccumulation, reaching toxic levels in predators.
125
Q

What does IPM stand for?

A

Integrated pest management

126
Q

What is integrated pest management?

A

IPM involves the development of an overall strategy, with a range of control measures and the goal of significantly reducing or eliminating the use of pesticides while at the same time managing pest populations at an acceptable level.

127
Q

Name some IPM measures and comment on why they are effective

A
  1. Selecting varieties best suited for local growing conditions.
    - Comment: The most productive variety would be avoided if it was susceptible to local pests.
  2. Crop rotation and/or intercropping.
    - Comment: Harder for pest species to become established.
  3. Monitoring pest levels.
    - Comment: To determine the need for control measures.
  4. Using photodegradable plastic around and between crop plants (e.g. maize)
    - Comment: Prevents the growth of weeds, reducing dependence on herbicides.
  5. Using methods to disrupt the breeding of pests.
    - Comments:
    • Crop rotation.
    • Use of mechanical traps.
    • Use of sterile males of pest species.
  6. Using specific, natural predators or parasites of pests - biological control.
    - Comments:
    • Long term control without the problems associated with chemical control.
    • Emphasis on control, not eradication.
  7. Using narrow-spectrum, biodegradable pesticides, which target the pest species; only used as a last resort when the pest may cause economic damage to the crop.
    - Comments:
    • Greater specificity in killing pest species means that pollinators and natural predators are not affected.
    • No bioaccumulation in food chains.
128
Q

Farmers are now …

A

More aware of the environmental implications of pesticide application

129
Q

Farmers are now more aware of the environmental implications of pesticide application. Give an example of this.

A

For example, an oilseed rape grower will only apply a (biodegradable) insecticide when an infestation of aphids has reached economic damage levels, and then only during the hours of darkness when bees (priority species) are inactive.

130
Q

Climate is a major factor in determining the distribution of species and the type of ecosystem that exists in an area. So any change in climate may be expected to have profound consequences:

A
  1. The distribution of species will shift northwards or to higher altitudes, if the habitat there is suitable.
  2. The extinction of some species is expected if they are not adapted to the changing environment and have nowhere suitable to move.
  3. The polar bear is threatened as the Arctic ice sheet decreases - it is predicted that there may be no summer ice at all.
  4. Drier conditions will reduce wetlands, important ecosystems for many plant and animals species.
  5. Sea level rises will affect many ecosystems and species dependent on the shoreline: salt marsh ecosystems could be lost; turtles could lose the beaches on which they nest.
  6. The acidification of the oceans (CO2 is acidic and very soluble in water) is a threat to the coral reef ecosystems.
131
Q

Overall, it is expected that climate change will result in …

A

The extinction of many species and the reduced diversity of ecosystems.

132
Q

Overall, it is expected that climate change will result in the extinction of many species and the reduced diversity of ecosystems. How can this be avoided?

A

A major reduction in the use of fossil fuels and a switch to alternative power sources such as wind and nuclear power, allied to increased energy saving schemes, are necessary to avoid major environmental change.

133
Q

DAERA has established a number of agri-environmental schemes, through a series of legislations and incentives, to conserve habitats and promote species diversity through:

A
  1. Hedge replanting and maintenance to promote hedge diversity.
  2. Restrictions regarding the application of organic and inorganic fertilisers.
  3. Leaving ungrazed margins in fields and other farmland areas (field corners and steep slopes) to allow insects and wildflowers to grow, with applications of fertiliser and pesticides prohibited, and so providing a habitat and food source for a range of birds and mammals.
  4. Retention of winter stubble, from cereals or oilseed rape, to benefit seed-eating birds that feed on grain left behind after harvesting.
  5. Planting cereal crops that must not be treated with herbicides (‘conservation cereal’) to allow a range of weeds in the crop to benefit farmland birds that feed on invertebrates and weed seeds.
  6. Maintenance of priority habitats on farmland (e.g. species-rich grassland, wetlands) through restrictions - pesticides, fertilisers (organic or inorganic) and drainage are not permitted.
  7. Other species schemes, for example:
    - Leaving uncultivated (fallow) plots to provide lapwings (a species of bird) with nesting sites.
    - Planting a mix of different legumes to supply pollen and nectar for bumblebees and butterflies.
134
Q

What is flora and fauna?

A

Flora is the plant life occurring in a particular region or time, generally the naturally occurring or indigenous—native plant life. The corresponding term for animal life is fauna.

AS Biology Module 2 - Organisms and Biodiversity (6 decks)

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