Agricultural Intensification

Question 1

Food security

Answer 1

over the last 40 years major increase in production sees main grains produced 3x more in 50 years, and 4.5x more chicken, 2x more pigs

This is due to expansion of agricultural land and intensification of agriculture

Question 2

Around 35% of global land is agricultural area

Answer 2

But hectares per capita is decreasing, yield increasing

Question 3

5% increase per annum meat consumption in developing countries (livestock production causes 18% greenhouse gases)

Answer 3

2012 - 7 billion people; 2046 - 9 billion people

Question 4

Prices for meat, cereal, and all foods

Answer 4

has increased dramatically over the last 20 years. Controversy with biofuels as it’s burning food

Question 5

Food prices impacted by

Commodity trading
e.g. 2010 Russian wildfires & drought.
Yield reduced by <5%. Prices increased 50%

Increased oil prices

Answer 5

Climate trends were large enough in some countries to offset a significant portion of the increases in average yields that arose from technology, carbon dioxide fertilization, and other factors.

Question 6

A third of food produced is wasted

Answer 6

But tackling waste not sufficient to meet demand

Developing countries 1/3 waste is on-farm, 1/3 through transport and processing Godfray et al. 2010 Science 327, 812-818

Developed countries 1/3 of waste is at home and municipal

Question 7

AGRICULTURAL EXTENT

Answer 7

Globally humans acquire 30% of net primary productivity; 72% western Europe. Imhoff et al 2004 Nature 429, 870–873

Question 8

Change in area of annual crops 1999-2008 increasing greatly in Africa and brazil and India

Answer 8

Land converted to crop and pasture has increased 50% in 300 years. Most of which are endemic bird areas

Question 9

Pesticide and land use

Answer 9

are increasing a lot

Question 10

AGRICULTURAL IMPACTS

Answer 10

20-25% of pre-agricultural bird numbers lost by 1990 Gaston et al 2003 Proc Roy Soc B 276, 1293-1300

Agriculture is the biggest threat to globally endangered bird species

Similar for other groups eg 80% of threatened vertebrates (amphibians and reptiles)

Question 11

Increased yield and intensive productions lead to

Answer 11

decreased population in farmland birds

Question 12

More plants become classified as rare or threatened

Answer 12

as yield increases and production is intensified

Question 13

Intensification of agriculture and bees

Answer 13

Organic areas near to natural areas increase plant diversity but not when organic far from natural areas and not with conventional far from natural areas

Question 14

Livestock and wild environments

Answer 14

livestock grazed lands have 10 times less total animal biomass than livestock-free lands, same for overall density

Question 15

Cattle & zebra diets & habitat selection very similar Experiment Laikipia, Kenya (Young et al. 2005)
c. 10 cattle/km2 & 0 cattle/km2
excluding cattle increases zebra by 46%

Answer 15

Grass cover reduced by cattle & correlates +ve zebra Indirect facilitation - effects reduced by elephants

Question 16

Wild game better adapted than livestock Fewer inputs & less habitat modification Britain: deer, rabbits etc.

Answer 16

BUT
Needs policy and legislative change
Setting quotas
Creates extra bushmeat demand? Enforcement

Question 17

Strategy for policy change

Answer 17

Monitoring - Diagnosis - Design & test solutions - Deploy effective management - Monitor Outcome

Requires sound science, economic and environmental drivers, government, NGOs, Farmers and Industry, Effective technology transfer

Question 18

Philpott et al 2008 Conservation Biology

Answer 18

Certification in coffee in costa rica

Question 19

Cirl bunting distribution

Voluntary set-aside - RSPB stubble - Set-aside - Countryside stewardship special projects increased cirl population

Answer 19

Habitat requirements
• Weedycerealstubbles(winter)
• Mix of grassland (insects) & cereals (ripening grain) (summer)
• Winter & summer habitat close together
• Polarization of farmland & increased herbicide, insecticide and fertilizer use have all contributed to cirl decline

Question 20

UK agri-environment schemes

Answer 20

Entry level stewardship:
−Launched 2005
−Uptake relatively high
−Clearly defined broad objectives
−Evidence-based simple prescriptions

Higher level stewardship handbook
-- Launched 2005
− Uptake lower
− Clearly defined, narrow objectives
−Evidence-based complex prescriptions
− Geographical targeting
− Project officers
− Payments linked to delivery of habitat quality

Question 21

Review of agri-environment schemes

Answer 21

5 European countries & 202 paired fields
Marginal to moderate benefits in all countries
Common species benefit more than rare ones Red data book species rarely benefit
More detailed tailoring of schemes required

Question 22

RSPB Hope Farm Breeding Bird Index 2017

Answer 22

Skylark 10 to 35 pairs from 2000 to 2017 Grey partridge 0 to 7 pairs Starling 3 to 16 pairs
Linnet 6 to 22 pairs Yellowhammer 14 to 34 pairs
Average profit £60,000 per annum

Question 23

Land sparing is best for most populations

Answer 23

aka by the highest permissible yield

Question 24

But low intensity farming can be essential

Answer 24

30 globally endangered bird species rely on low intensity farming

Question 25

Land-sparing core assumption

Answer 25

Intensification means inefficient farms are abandoned and rural to urban migration which lead to forest regeneration

Question 26

Land-sparing model’s core assumption

Perfecto & Vandermeer 2010 PNAS 107, 5786-5791

Answer 26

El Salvador: local rural population density uncorrelated with forest recovery
Argentina: rural population declining, but forest cover also declining
Mexico: 16 of 17 studies conditions meet forest transition model, but still net deforestation
Costa Rica: intensification, rural to urban migration & ecotourism revenues, but forest fragmentation continues

Question 27

SUMMARY

Answer 27

Much of the globe’s land is used for food production

Area of farmland and intensification will increase in the future

Agricultural expansion and intensification drive wildlife declines

But agri-environment schemes based on strong science can reduce the negative impact
Much debate regarding land-sharing vs sparing approaches

Question 28

Reading list

Answer 28

Phalan et al 2011 Science 333, 1289-1291

Macedo et al 2012 PNAS 109, 1341-1346

Perfecto & Vandermeer 2010 PNAS 107, 5786-5791