Managing farming to reduce biodiversity loss Flashcards
Global expansion of agriculture
- Oil palm 56% expansion from 1999 - 2008
- Soya bean 33%
- Cocoa bean 32%
- Bamboo 26%
1980-2012
154 Mha converted, 77 x Wales
Global imbalance in deforestation
mainly in southern hemisphere, in tropical regions
Massive loss of biodiversity
Threats to IUCN status of species in the tropics are higher than elsewhere
Cultivated lands are vastly simplified systems
And human population is rapidly expanding (will reach 11 billion by 2100)
1.5 billion overweight and obese people
More meat consumption per capita as population increases
Usable protein per acre of farmland
18x more protein per hectare from soy than from beef
More biofuel use boosts agriculture
More US corn grown for biofuel than for animal feed in 2010
In the next 40 years agricultural production could grow by
60-100%
Agriculture is key driver of extinction crisis
Growing demand for food and biofuels
Future of global biodiversity in hands of agricultural policymakers
How best to manage agriculture expansion to minimize biodiversity loss?
(1) “Land-sharing” or “land-sparing” farming
(2) Expand in low biodiversity areas
Land-sharing
Farm at lower intensity Organic farming Set-aside strips Hedgerows 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
Which strategy (sharing or sparing) is best for species?
plot a density-yield curve for total abundance of each species across landscapes
A convex relationship between yield of food and species abundance means land-sparing is best.
A concave relationship means land-sharing is best.
Sharing or sparing for oil palm?
Trees are all “losers”, but land-sparing is best, especially for species with small ranges.
But previous work has ignored potential role of surrounding landscapes
- Species could disperse into test landscapes from forest elsewhere
- Species could use resources from outside test landscape
Land-sparing is best for biodiversity
More species have higher abundance
Higher landscape-level species richness
Land-sparing is increasingly better further from contiguous forest edge
Land-sparing also best for carbon
Need to intensify existing tropical farmland
Many areas have already been degraded across the tropics
Burned multiple times
Erosion
Converted to farmland
Imperata grasslands in SE Asia
What if Imperata is the focus of new farmland?
Can meet 2020 oil palm demand without forest loss if focus on degraded lands
Predictions from coarse-grain species layers
Can overlook important habitat for conservation at smaller scales
Two habitats dominate in the Llanos:
Anthropogenic / semi-natural grassland
Natural forest patches
Can oil palm develop at minimal cost to biodiversity in either of these two habitats?
Effect of oil palm on biodiversity
1) Species richness differs
2) Species composition differs
3) Forest species decline
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
Sustainability labelling
Media and consumer pressure
Greenpeace vs
400 global retailers ($2.8 trillion) cut all deforestation from supply chains by 2020
Cost of removing deforestation?
Simulate where to put new oil palm to avoid deforestation: Meet 2025 production Calculate rent of current land use Predict oil palm rent Choose most profitable cells
