Agrobiodiversity and Ecosystem Services Reevaluating the benefits of agricultural landscapes

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Agrobiodiversity and Ecosystem ServicesRe-evaluat
ing the benefits of agricultural landscapes

• Charles Perrings
• ecoSERVICES Group, Arizona State University

The Seventh Nekudat Hen Seminar 3 November 2009
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Biodiversity in agroecosystems

• Agricultural biodiversity (agrobiodiversity)
• the variety and variability of plants, animals
  and micro-organisms that are useful in managed
  ecosystems, and
• the ecological complexes of which they are part,
  including genetic, species, population, ecosystem
  and landscape interactions (McNeely Scherr
  2003)

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Declining agrobiodiversity

• 7,000 plant species have been used as food
  (Hammer et al. 2003), but just 15 crops now
  provide 90 of the world's food energy intake
• Traditional medicines from natural sources
  provide health care for 80 of the worlds
  population (WHO 2003)
• 28 of livestock breeds (3237 breeds at present)
  have become rare or extinct in the last 100 years
  (Tisdell 2003)

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Threatened species (IUCN)

• lt1 of all species are globally threatened, but
  24 of mammal and 12 of bird species are
  threatened
• Agriculture affects 92 of mammal, 70 of bird
  and 49 of plant threatened species (Dirzo
  Raven 2003)

mammal bird reptile amphibian fish
moss gymno dicot monocot
insect mollusc crustacean other
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Biodiversity and functioning of ecosystems

• Higher plant diversity increases productivity of
  grasslands (Tilman et al. 2002, Loreau et al.
  2004)
• Functional complementarity different species
  function in different ways
• Spatial heterogeneity favors coexistence of
  different species
• Redundancy number of species is less important
  for ecosystem services than the presence of
  functional groups
• Resilience persisting and adapting to change
• Adaptive capacity options forreorganization
  followingchange that reduce vulnerability
• Insurance value risk mitigationespecially at
  the landscape scale

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Habitat complexity can enhance biodiversity and
ecological functioning

• Moderately disturbed agricultural habitats
  support more species
• Intermediate disturbance hypothesis (Connell
  1978)
• Crop mixtures decrease arthropod herbivores
• Natural enemies and resource concentration
  hypotheses (Root 1973)
• Soil biodiversity and activity may reduce disease
• General and specific suppression hypotheses (Cook
  Baker 1983)
• More heterogeneity within and between vegetation
  fragments increases gene flow and biodiversity
• Metapopulation theory (Soulé 1987)

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Landscape level agrobiodiversity
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Landscape Configuration and Ecosystem Services
Land sparing agriculture coarse grain, abrupt
change
Wildlife-friendly agriculture fine grain,
spatial continuity
Synergy model
Tradeoff model
(Slide due to A. Power, from Fischer et al. 2008)
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From ecological functioning to ecosystem services
Millennium Ecosystem Assessment (2005) Ecosystems
and Human Well-Being Synthesis. Island press,
Washington D.C.
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Ecosystem Services status
Millennium Ecosystem Assessment (2005) Ecosystems
and Human Well-Being Synthesis. Island press,
Washington D.C.
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Ecosystem services in agroecosystems
Priced in the market
Affects mean output

• Supporting services
• Nutrient recycling
• Photosynthesis
• Pollination

• Provisioning services
• Foods, fuels, fibers
• Water yields
• Genetic material

• Regulating services
• Soil erosion control
• Pest control
• Hydrological control
• Pollution buffering
• Microclimatic control

• Cultural services
• Recreation
• Spiritual renewal
• Aesthetic pleasure
• Sense of place
• Scientific information

Agroecosystems
Not priced in the market
Affects the variance of output
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Biodiversity, ecological functioning and
ecosystem services
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Agrobiodiversity and ecosystem services the
economic problem

• Ecosystem services are the benefits that people
  obtain from ecosystems.
• Since the value of any asset is the discounted
  stream of benefits it produces, the discounted
  stream of ecosystem services defines the value of
  ecosystems.
• In some circumstances (well-defined property
  rights, complete markets, perfect information
  etc) the market prices of ecosystem services will
  be good measures of their value.

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Agrobiodiversity and ecosystem services the
economic problem

• Many ecosystem services are not priced in the
  market, or if they are their market prices are
  not good measures of their value.
• To understand the social value of agroecosystems,
  we need to understand the value of the ecosystem
  services they produce.
• This requires identification and valuation of
  off-site benefits or costs that lie outside the
  market..
• ..plus mechanisms to internalize those benefits
  or costs (to ensure that farmers are compensated
  or penalized).

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Spatially distributed agricultural
externalities the downside

• La Sepultura Reserve
• 167 000 ha buffer zone another 150 000 ha
• Tropical forest deciduous ? evergreen cloud
  forest
• Buffer zone Heavy extraction of forest products
• Agriculture
• Slash and burn for maize-bean-squash
• Pasture
• Rustic coffee
• Landslides and flooding due to deforestation and
  slash and burn agriculture.

Sierra Madre de Chiapas, MexicoDeforestation
and erosion
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The dead zone in the Gulf of Mexico

• N and P run-off cause seasonal oxygen levels to
  be too low to support life in bottom and
  near-bottom waters.
• Hypoxic conditions results in an overgrowth of
  algae, which decomposes and sinks to the seafloor
  where bacteria break it down and release carbon
  dioxide.
• The dead zone reached a record size of nearly
  9,000 square miles in 2008

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Origins of the dead zone
Watersheds from which nutrient run-off most
affects the dead-zone
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which maps in areas of intensive agriculture
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Solutions to the N pollution problem

• The impacts of nitrate pollution on aquatic
  systems (esp marine systems) is an externality of
  agriculture
• May be internalized with a tax on N fertilizer to
  reflect the external cost of nitrate pollution

Marginal external costs of N
Costs, benefits of N
Marginal net private benefits
C
N application
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Spatially distributed agricultural
externalities the upside

• Positive off-site externalities from on-farm land
  management strategies include a number of
  cultural services
• Provision of habitat for beneficial species
• Maintenance of valued landscape
• Recreation and tourism (markets exist)
• A sense of place
• Satisfaction of cultural need for association
  with the land

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Spatially distributed agricultural
externalities the regulating services

• Many of the most important off-site externalities
  relate to the regulating services
• Regulation of water quality and quantity
• Regulation of soil erosion
• Regulation of pest predation
• Regulation of disease transmission
• Reduced vulnerability to invasive species
• Biocorridor provision mitigates risks to
  metacommunities

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Payments to internalize positive off-site
environmental externalities

• Payments for Ecosystem Services (PES) schemes
  address the market failures involved where
  ecosystem services are public goods or
  externalities of market production.
• PES schemes are designed to stimulate
  transactions in which a an ecosystem service is
  bought by users from providers.
• The payments involve a positive incentive to the
  provider, and are conditional on performance.
• Because of the difficulty in measuring many
  environmental services directly, payments may be
  based on either the actions of the service
  providers or on indirect ecological indicators.

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Current status of PES schemes

• Hundreds of PES schemes are being implemented
  around the world covering four main ecosystem
  services
• water provisioning,
• carbon sequestration,
• landscape amenity, and
• biodiversity conservation.
• Most current PES schemes are local level
  arrangements and involve spontaneous, private
  markets.
• Large PES schemes tend to be government driven,
  working at the state and provincial level (e.g.
  in Australia, Brazil, China and USA), or at
  national level (e.g. Colombia, Costa Rica, China
  and Mexico).

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Payments for ecosystem services

• If land users do not receive compensation for the
  production of valuable ecosystem services, they
  will not provide them.
• PES systems, like other market mechanisms, induce
  land managers to incorporate the economic value
  of ecosystem services into their financial
  decisions.
• Their principal attraction is that they enhance
  efficiency.

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PES schemes for water provision

• PES schemes for water provision exist in all
  countries shaded green.

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PES schemes for agrobiodiversity

• Countries implementing schemes for
  agrobiodiversity are shaded yellow.

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Evaluation of the effectiveness of PES schemes
Arriagada R. and C. Perrings (2009) Making
Payments for Ecosystem Services Work, Working
Paper, UNEP, Nairobi.
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Agrobiodiversity conservation

• While there are agrobiodiversity PES schemes, and
  while agrobiodiversity is a recognised target for
  some payments under the CAP and other major
  agricultural policies, agrobiodiversity has a
  generally low priority.
• In situ conservation of land-races, wild crop
  relatives and traditional livestock strains
  attracts little support.
• In situ conservation of associated species
  attracts even less.

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Biodiversity conservation priorities by society
at present

• High Protected natural/wildland areas
• Existence value of species threatened by
  extinction
• Moderate Agricultural production systems
• Direct use value from ecosystem goods and
  services
• Option value for the future, e.g., gene banks
• Low Agricultural landscapes
• Complex mosaic of ecosystems and biota how do
  they interact?
• Human-induced environmental change Does a
  biodiverse landscape provide resilience and risk
  mitigation?

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Protected areas

• 11 of all land is in protected areas, e.g. parks
  and reserves (IUCN 2000)
• Agriculture occurs in 29 of the protected
  reserves (McNeely and Scherr 2003)
• Agrobiodiversity objectives
• Widen conservationboundaries to include
  forest-agriculture ecotones as an inclusive
  landscape unit
• Increase income from off-site ecosystem service
  flows from agricultural landscapes

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What should motivate conservation of crop genetic
diversity

• Homogenization of production agriculture
  increases the spatial correlation of risks
• In Vavilov megadiversity areas farmers are able
  to manage risk through conservation of crop
  genetic diversity
• In genetically depauperate areas risks are highly
  correlated spatially

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What should motivate conservation of crop
agrobiodiversity more generally

• Agrobiodiversity has an important regulatory
  function not just for crop production but for
  a range of off-site ecosystem service flows.
• Arobiodiversity also supports important cultural
  services, and these grow as communities become
  more urbanized

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Optimal conservation

• There is a simple test for the conditions under
  which it is optimal to conserve any resource
  (whether stocks of oil or agrobiodiversity). The
  test is due to Harold Hotelling.
• It will be optimal to refrain from converting a
  resource to some alternative use so long as its
  in situ social value is rising at least as fast
  as the return to be had from its conversion.
• This supposes that the resource is valued at its
  social opportunity cost, and not its market price
  i.e. at its value to society and not its value
  to the private individual.

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Investing in agroecological assets

• It follows that it should pay to invest in the
  agroecosystems that yield services whose value is
  rising faster than the return on the land if
  converted to some alternative use.
• If the value of ecosystem services can be
  realized through the market it may be sufficient
  to support establishment of a market.
• If the value of ecosystem services cannot be
  realized through the market (because the services
  are, e.g., public goods) it may be necessary to
  implement a PES scheme funded through taxation.

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The consequence of underinvestment in
agroecosystems Adjusted Net Savings in Poor
Countries
http//web.worldbank.org/WBSITE/EXTERNAL/TOPICS/EN
VIRONMENT/EXTEEI/0,,contentMDK20502388menuPK118
7778pagePK148956piPK216618theSitePK408050,00
.html
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Concluding remarks

• While agroecosystems in developed countries are
  not being degraded in the same way, there is
  still a significant gap between their market
  value and their value to society.
• To assure the efficient use of agroecological
  resources it is important to identify and value
  off-site ecosystem service flows
• Increasing urbanization means increasing demand
  not just for the core provisioning services, but
  also for many cultural services, and for the
  regulating effects of farm systems on water
  quality and quantity.

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Acknowledgements

• DIVERSITAS Agrobiodiversity Network (Louise
  Jackson)
• Alison Power
• NSF BESTNet Project