managing farming to reduce biodiversity loss

Question 1

How is agriculture expanding in the tropics?

Answer 1

• expanding globally
• 154 million hectares converted between 1980-2012
• rapidly expanding human population
• meat consumption growing
• but get 16x more protein per hectare from soy than beef
• more biofuel use (more US corn for biofuel than animal feed)
• production could grow 60-100% in next 40 years
• palm oil 56%
• soya 33%
• cocoa 32%
• sugarcane 26%

Question 2

What are the biological costs of conversion to agriculture?

Answer 2

• massive loss of diversity
• usually loss of abundance
• systems vastly simplified by conversion

Question 3

What is land-sharing vs land-sparing?

Answer 3

Land-sharing:

• farm at lower intensity
• organic farming
• set aside strips
• woodlots/fragments
• biodiversity protected within agricultural matrix

Land-sparing:

• farm at high intensity
• industrial farming
• use less land to meet demand
• biodiversity protected within remaining natural forest

Question 4

Is land sharing or sparing best?

Answer 4

• calculate species abundance across land scape
• density yield curves
• if convex (bends in on itself) land sparing best
• if concave (bends out) land sharing is best

Question 5

Which strategy is better for species?

Answer 5

• land sparing is best in oil palm (Phalan et al., 2011)
• especially for species with small ranges
• previous work ignored potential role of surrounding landscapes (e.g. dispersal from/resource utilisation of areas outside test landscape (source-sink dynamics)

Question 6

What is the impact of landscape configuration (land-sparing/land-scharing)?

Answer 6

Gilroy et al., 2014

• focus on cattle farming in Andes
• sample birds in cattle pastures and forest
• sample at range of distances from contiguous
• land-sparing is best for biodiversity
• more species have higher abundance
• higher landscape-level species richness
• increasingly better from contiguous forest edge
• also best for carbon
• we should intensify existing tropical farmland, not clear more

Question 7

How would expanding in low biodiversity areas?

Answer 7

• many areas already degraded in the tropics
  e. g. burned multiple times, erosion, converted to farmland

e. g. Imperata grasslands in SE Asia
- 2020 oil palm demand could be reached in focus on degraded lands

Question 8

What’s the effect of oil palm & pasture?

Answer 8

• species richness differs
• species composition
• forest species decline

Question 9

What should we conclude about agricultural conversion of tropical forests?

Answer 9

• forest patches have most species
• oil palm more species rich than pasture
• forest species have higher occurrence in oil palm than in pasture
• minimal biodiversity impacts of converting intensive - Llanos pasture to oil palm
• but vital to preserve forest patches
• how can we persuade the oil palm industry to direct development to such areas?

sustainability (‘green’) labelling

Question 10

What is sustainability (“green”) labelling?

Answer 10

• media & consumer pressure
• e.g. greenpeace campaigns: killer vs kitkat
• 400 global retailers to worth $2.8T cut all deforestation from supply chains by 2020

Question 11

What is the cost of removing deforestation from the supply change?

Answer 11

• to meet 2025 production need for oil palm
• simulate where to ut new oil palm to avoid deforestation
• calculate rent of current land use
• predict oil palm rent
• choose most profitable cells
• increases production cost by $30 per tonne
• e.g. increase in mars bars cost for 0.0001p
• demand deforestation free products!!!
• caveat: not enough forest free areas to meet demand beyond 2025

Question 12

What are the pros/cons of high yielding crop varieties?

Answer 12

• more crop per hectare
• Sime Darby “superpalms” 10 tonnes of crude palm oil per hectare vs usual 4
• genome sequencing opens way for producing pest & drought resistance
• big potential for saving forest

BUT

• markets are globally interconnected
• buyers can substitute one crop for another: 53% oil palm yield increase would lead to 4.3% price fall
• transfer of food production from temperate to tropics & leading to more deforestation
• need government to zone areas for high yielding crops coupled with forest estates
• without this safeguard, land sparing could be in the temperate zone

Question 13

summary

Answer 13

• expansion of tropical farmland is the biggest driver of global extinction crisis
• growing demand means production may double by 2050
• land sharing vs land sparing paradigm
• sparing best, but need adequate safeguards
• degraded (non-forest) areas can be used
• sustainability to access western markets
• effective land zoning to stop deforestation