Human Impacts

Question 1

What is Monoculture

Answer 1

Growing a single crop in large fields, year after year, eg barley

Question 2

What are the benefits of Monoculture

Answer 2

-Economic Benefit- food can be grown more cheaply as the increase in mechanisation and the reduction in labour means that continuous harvesting of one crop brings a greater economic return per unit area of land

Question 3

What are the problems with Monoculture

Answer 3

-reduces biodiversity- hedgerow removal and increased mechanisation
-problem with weeds
-depletion of minerals in the soil due to specific demands of one crop in addition to the crop being harvested before decay and decomposition
-problem with pests and diseases causing a loss in crop yield

Question 4

What is artificial fertiliser

Answer 4

-Mainly Nitrates and phosphates
-maximise cropyield by increasing the use of artificial fertiliser
-nitrates- promote faster growth
-maintain high stocking rates of livestock

Question 5

Problems with artificial fertiliser

Answer 5

-target crop outcompetes and eliminates slower growoing crops
-decline in the soil crumb structure as no organic matter is added- soil erosion
-risk of Eutrophication- fertiliser leaches from soil
-reduces biodiversity

Question 6

Hedgerow removal

Answer 6

-land cleared for crop growing, and meet increased food demands

Question 7

Problems with Hedgerow removal

Answer 7

-loss of habitats for plant and animal species
-loss of food for animals
-loss of wildlife corridors to facilitate the movement of small species
-increased soil erosion- exposure of wind and rain and reduction of roots to bind the soil

Question 8

Pesticides

Answer 8

-A pest is a species that damages a commercial crop causing economic damage
-Increased dependancy on pesticides to maximise crop production by eliminating pests

Question 9

Problems with pesticides

Answer 9

-Broad spectrum- kill other species other that the target species- reduces biodiversity
-kiss soil organisms- including those that play a role in improving soil structure
-eliminates natural predators- leads to pest resurgence
-pesticide use is increasing but efficiency is decreasing- reduction in biodiversity
-mammals and birds may be affected by bioaccumulation or pesticides (build up in tissues) in the food chain and loss of food sources

Question 10

What is Organic Pollution

Answer 10

-Water pollution by organic material, eg slurry, sewage, silage effluent and spilled milk

Question 11

What effect does organic pollution have on biodiversity

Answer 11

-Pollutants contain a rich source of nutrients for BACTERIA
-explosion of the bacteriac (saprophytic) uses up the oxygen by aerobic respiration
-Deoxygenation is the main effect of organic effluent- results in high BOD and reduced Biodiversity

Question 12

What is Biological Oxygen Demand

Answer 12

-Water quality
-Measured as the usage of oxygen in the water
-high bacteria levels due to pollution results in more aerobic respiration leading to high BOD

Question 13

What is an Indicator Species

Answer 13

Specific species that are adapted to different levels of oxygen in the river, and act as Indicator Species

-HIGH OXYGEN- unpolluted, eg stonefly

-MEDIUM OXYGEN- moderate pollution, eg midge larvae (bloodworms)

-LOW OXYGEN- polluted, eg sludge worms- red in colour due to rich stores of haemoglobin (oxygen stores), low metabolic rate and low oxygen demands