Human Impact on Biodiversity

Question 1

what is biodiversity?

Answer 1

-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

Question 2

what are intensive agricultural practices meant to do?

Answer 2

-designed to maximize productivity (increased food production)
-maximize profit

Question 3

what has been the result of agricultural intensification in N.I ?

Answer 3

-significant reduction in biodiversity as a consequence of habitat loss and habitat change for a number of reasons

Question 4

what are the 5 things that can result in habitat loss and change?

Answer 4

-increased use of monoculture
-nutrient enrichment of soils
-loss of hedgerow and woodland
-increased use of pesticides
-broad spectrum pesticides which can also be known as insecticides

Question 5

what is monoculture? what is an example of this?

Answer 5

-whole areas of farmland that is given over to one species of crop e.g. barley which is ideal for grazing for cattle and sheep

Question 6

where is monoculture commonly practiced ?

Answer 6

-common on large farms due to the economy of scale which is involved in ground preparation , planting and harvesting

Question 7

what are some of the problems with monoculture?

Answer 7

-can cause the build up of pests specific to the crop being grown
-growing the same crop in the same land can lead to the reduction of certain minerals in soil because each successive crop has the same mineral ion requirements
-the crop is invariably harvested before decay and decomposition can take place and return the mineral ions back to the soil

Question 8

what practice is nutrient enrichment associated with and what impact does nutrient enrichment have on biodiversity?

Answer 8

-monoculture is associated with nutrient enrichment of soils to maximize crop yield
-use of artificial fertilizer with high levels of nitrate encourages the fast growth of a particular crop
-this is harmful to biodiversity as it allows target crop to outcompete other slower growing species

Question 9

what are the two common mineral ions associated with nutrient enrichment ?

Answer 9

-nitrate and phosphate

Question 10

how can nutrient enrichment result in increased soil erosion?

Answer 10

-it can lead to loss of soil crumb structure

Question 11

what is the main job of nutrient enrichment?

Answer 11

-used to maintain high stock rates in livestock farming

Question 12

how can a loss of hedgerow and woodland result in decreased biodiversity?

Answer 12

-leads to loss of biodiversity through loss of habitat and food for many hedgerow species
-this impacts adversely on their species e.g. those higher up the food chain as they now don’t have a food source

Question 13

what are wildlife corridors?

Answer 13

-hedgerows can also act as wildlife corridors which links areas of woodland or other species rich habitats

Question 14

what are the 4 advantages of wildlife corridors?

Answer 14

-provide habitats for species
-provide shelter for species
-cuts down on wind speed which prevents erosion
-provides food for species

Question 15

what are 4 reasons why hedgerows can be removed?

Answer 15

-increase the size of the field
-hedgerows could be damaged and need replaced
-saves time and money on its maintenance
-machinery needed to maintain hedgerows in very large so only works effectively in large fields where there is lots of space

Question 16

how can increased use of pesticides result in loss of biodiversity?

Answer 16

-used to maximize crop production through eliminating pests that reduce population
-specific pesticide is necessary to eliminated specific pests

Question 17

what is the definition of a pest?

Answer 17

-pest can be defined as a species that damages a valuable crop species which causes economic damage

Question 18

what is another name for broad spectrum pesticides?

Answer 18

-insecticides

Question 19

why can broad spectrum pesticides/ insecticides cause a loss in biodiversity?

Answer 19

-they kill organisms of species other than the intended target
-they kill soil organisms that are involved in decomposition and improving soil structure
-they eliminate natural predators of the main pest and cause pest resurgence which allows the pest to return in greater numbers

Question 20

what are herbicides and what is its effect on biodiversity?

Answer 20

-they are a particular types of pesticide used to eliminate weeds
-it reduces plant biodiversity as it eliminated non-crop species and reduces the variety of food available to animal species which reduces animals biodiversity too

Question 21

what happens of some species become resistant to pesticides?

Answer 21

-there can be issues with bioaccumulation which involves the build up of concentrations of potentially harmful substances in the tissues of organisms at higher trophic levels

Question 22

what some of the agricultural activity that promotes biodiversity?

Answer 22

-polyculture
-increased use of organic fertilizer
-hedgerow conservation and maintenance
-integrated pest management through the use of narrow spectrum pesticides

Question 23

what is polyculture?

Answer 23

-this is the growing of a range of different crops at the one time or sequentially in the one place

Question 24

what are some of the advantages of polyculture?

Answer 24

-provision of a wider range of food sources
-more habitats for wild life
-greater number of and more complex food webs

Question 25

what is the main type of poly culture?

Answer 25

-crop rotation which is the planting if different types of crops in the same field over a period of years

Question 26

why is crop rotation effective?

Answer 26

-helps to conserve soil fertility as different crops have different demands of soil nutrients
-it improves soil fertility when nitrogen fixing crops like peas are part of the cycle
-reduces the likelihood of a build up of pests specific to one crop

Question 27

why does an increased use of organic fertilizer help promote biodiversity?

Answer 27

-use of organic fertilizer (farmyard manure) and the consequent decrease of artificial fertilizer helps to promote soil fertility
-this helps to preserve soil crumb as the humus (dark organic material formed in soil when plants or animals decay) helps to hold soil crumb structure together
-it releases nutrients at a slower rate due to less leeching with less mineral loss as the plants make better use of these slow released ions

Question 28

what is one of the disadvantages of organic fertilizer?

Answer 28

-more difficult to store and spread than artificial fertilizer and its nutrient content is more variable

Question 29

how can hedgerow maintenance help promote biodiversity?

Answer 29

-hedgerows that are most likely to encourage biodiversity are those that contain a range of shrub and tree species which provides a range of different food sources for animals

Question 29

how can biodiversity friendly hedgerow trimming increase biodiversity? (4 ways)

Answer 29

-allows hedgerow trees to grow to maturity
-only trim of 2-3 year rotation which allows shrubs to produce berries which is food for birds over winter
-trimming in late winter avoids destruction of birds nest, during spring and summer, lets berries develop in the autumn which provides food for birds
-maintain a range of height and widths by staggering trimming regimes which allows a range of habitats, hedges cut in A shape can be very diverse as this allows more light to penetrate to ground level

Question 30

how can young hedgerows be protected from grazing by animals?

Answer 30

-this can be done by planting the hedge between a double fence which both protects the young hedge and forms an effective boundary
-in due course the fence can be removed

Question 31

how can integrated pest management help promote biodiversity?

Answer 31

-more integrated pest management approaches are now being encouraged which include the use of narrow spectrum pesticides that only affect the target pest species

Question 32

what is biological control?

Answer 32

-involves deliberately introducing a predator species that target the pest

Question 33

how can biological control promote biodiversity?

Answer 33

-benefits the environment by reducing the need for chemical pesticides and broad spectrum pesticides that often do not work well

Question 34

look in booklet and learn the graphs for pest resurgence

Answer 34

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Question 35

what are the 5 advantages to biological control?

Answer 35

-no chemical damage to environment which decreases the risk of ecological harm and bioaccumulation in food chains
-targets only the pest species and so there is reduced collateral damage affecting other organisms
-pest resistance is unlikely
-pest resurgence is unlikely
-if successful needs little addition action and saves money on the continued use of pesticides

Question 36

how can insect populations become resistant to insecticides?

Answer 36

-they frequently develop resistance to the pesticides and it ceases to become effective
-before pesticide is added a small number of individuals in population will have resistance due to mutation
-when the pesticide is used the non resistant individuals are killed leaving only the resistant to reproduce and so results in the population becoming resistant

Question 37

what are some of the limitations of biological control?

Answer 37

-pest will not be totally eliminated only its density will be reduces usually below the threshold for economic damage
-it will only work of the biological species can adapt and thrive in the ecosystem it is introduced into
-often due to an unnatural ecosystem not found in the wild it can be hostile to the introduced biological species

Question 38

what are predator strips?

Answer 38

-they will increase the number of many pests’ natural predators on the farmland

Question 39

what is the effect of inappropriate farming practices of waterways?

Answer 39

-it can result in their pollution