Lecture 12 - managing farming to reduce biodiversity loss Flashcards

1
Q

what is the biggest driver of the global extinction crisis

A

extreme global expansion of tropical agriculture - primarily at the expense tropical rainforest (global imbalance in deforestation)

  • resulting in massive loss of biodiversity
  • 1980-2012 = 154 Mha converted
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2
Q

why is agriculture such a big problem?

A

agricultural systems are vastly simplified compared to rainforests
- forest conversion is set to continue due to rapidly expanding population, more people =more mouths to feed (1.5 billion overweight/obese people)

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3
Q

explain the issue of meat consumption

A

there is currently more meat consumption per capita but you can get 18x more protein Ha-1 from soy than beef - beef is less sustainable

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4
Q

what is another use of agriculture other than direct food

A

increase in biofuel use - more US corn grown for biofuel than animal feed in 2010

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5
Q

what is the future of agriculture production

A

in the next 40 years, agricultural production could grow by 60-100%

  • may need to double farm output by 2050
  • future of global biodiversity in hands of agricultural policy makers
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6
Q

2 ways to manage agriculture expansion to minimise biodiversity loss

A

1) land sharing or land sparing farming

2) expand in low biodiversity areas

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7
Q

describe land sharing

A
  • farm at lower intensity
  • organic farming
  • set-aside strips
  • hedgerows
  • woodlots/fragments
  • biodiversity protected within agricultural matrix
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8
Q

describe land sparing

A
  • farm at high intensity
  • ‘industrial farming’
  • use less land to meet demand
  • biodiversity protected within remaining natural forest
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9
Q

how do you calculate which method of agriculture is best for a species

A
  • calculate the total abundance of each species across landscapes
  • plot a density-yield curve
  • shape of curve determines if land-sharing or land-sparing is best for a species
  • land sharing best = concave curve
  • land-sparing best = convex curve
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10
Q

describe the oil palm experiment in Ghana looking at land sharing vs land sparing

A
  • sampled birds and trees
  • compare the abundance of each species under land-sparing and land-sharing
  • divide them by winners and losers from farming
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11
Q

what are the results fo the Ghana experiment

A
  • in oil palm - land sparing is best - especially for species with small ranges
  • potential role of surrounding landscapes - species could disperse into test landscapes from forest elsewhere - species could use resources from outside landscape
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12
Q

what are source sink dynamics?

A

spillover of wildlife

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13
Q

describe an example where landscape configuration has an impact on which agricultural strategy is best

A

cattle farming in the Andes - sample birds in cattle pastures and forest

  • sample at a range of distances from contiguous forest
  • total species richness decreases with distance from forest for land sharing but stays relatively constant for land sparing
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14
Q

land sparing advantages

A

land sparing - best for biodiversity

  • need adequate safeguards
  • more species have higher abundance
  • higher landscape-level species richness
  • increasingly better further from contiguous forest edge
  • best for carbon storage
  • need to intensify existing tropical farmland
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15
Q

describe management of agriculture expansion by expanding in low biodiversity areas

A
  • using areas which have already been degraded across the tropics e.g. burned multiple times, erosion, converted farmland, imperata grasslands in SE Asia
  • can meet 2020 oil palm demand without forest loss if we focus on degraded lands
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16
Q

what two habitats dominate in the Llanos?

A

1) Anthropogenic/semi-natural grassland

2) natural forest patches

17
Q

describe the experiment investigating into development of oil palm at minimal cost to either habitat (anthropogenic/ semi natural grassland and natural forest patches)

A
  • study taxa - ants, dung beetles, birds, herpetofauna
  • study area
  • look at 3 effects of oil palm on biodiversity
    1) species richness - differs
    2) species composition - differs
    3) occurence of forest species in oil palm and pasture - declines
18
Q

summary of llanos experiment?

A
  • forest patches have most species
  • oil palm more species rich than pasture
  • forest species have higher occurence in oil palm than in pasture
  • minimal biodiversity impacts of converting llanos pasture to oil palm but is vital to preserve forest patches
19
Q

describe sustainability labelling

A
  • technique to persuade oil palm industry to develop in such areas
  • media and consumer pressure
  • advertising products that come from sustainable oil palm agriculture
  • 400 global retailers cut al deforestation from supply chains by 2020
  • deforestation free palm oil increases cost of production by what translates into mars bar price increase of 0.0001p
20
Q

what is the issue with expanding in low biodiversity areas

A

not enough forest free areas to meet demand beyond 2025

21
Q

what is a possible solution to meet high oil palm demand?

A
  • higher yielding varieties - produce more crop per ha on existing land
  • genome sequencing for producing pest and drought resistance - big forest saving potential
22
Q

what is the danger of yield increases?

A
  • markets are globally interconnected, buyers can substitute one crop for another - transfer from temperate to tropics
  • governments must zone areas for high-yielding crops coupled with forest estates
  • without this safeguard land sparing could be in the temperate zone