Abidi itAgrobiodiversityand EtE cosystem SiS ervices · Biodiversity in agroecosystems • Ai lt...
Transcript of Abidi itAgrobiodiversityand EtE cosystem SiS ervices · Biodiversity in agroecosystems • Ai lt...
A bi di it d E t S iAgrobiodiversity and Ecosystem ServicesRe‐evaluating the benefits of agricultural landscapes
Charles Perrings
ecoSERVICES Group, Arizona State University
The Seventh Nekudat Hen Seminar3 November 2009
Biodiversity in agroecosystemsBiodiversity in agroecosystems
A i lt l bi di it ( bi di it )• Agricultural biodiversity (agrobiodiversity)– the variety and variability of plants, animals and micro‐organisms that
are useful in managed ecosystems, and h l i l l f hi h h i l di i– the ecological complexes of which they are part, including genetic, species, population, ecosystem and landscape interactions (McNeely & Scherr 2003)
Declining agrobiodiversityDeclining agrobiodiversity
7 000 l t i h b d• 7,000 plant species have been used as food (Hammer et al. 2003), but just 15 crops now provide 90% of the15 crops now provide 90% of the world's food energy intake
• Traditional medicines from natural sources provide health care for 80% of the world’s population (WHO 2003)
• 28% of livestock breeds (3237 breeds at present) have become rare or
i i h l 100 (Ti d llextinct in the last 100 years (Tisdell2003)
Threatened species (IUCN)Threatened species (IUCN)
1% f ll i• <1% 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 andmammal, 70% of bird and 49% of plant threatened species (Dirzo & Raven 2003)2003)
mammal bird reptile amphibian fish
insect mollusc crustacean other
moss gymno dicot monocot
Biodiversity and functioning of ecosystemsBiodiversity and functioning of ecosystems
• Higher plant diversity increases productivity of grasslands• Higher plant diversity increases productivity of grasslands (Tilman et al. 2002, Loreau et al. 2004)– Functional complementarity: different species function in different waysFunctional 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• Resilience: persisting and adapting to change– Adaptive capacity: options for
reorganization followingchange that reduce vulnerability
– Insurance value: risk mitigationespecially at the landscape scaleespecially at the landscape scale
Habitat complexity can enhance biodiversity and ecological functioning• Moderately disturbed agricultural habitats support more
speciesIntermediate disturbance hypothesis (Connell 1978)– Intermediate disturbance hypothesis (Connell 1978)
• Crop mixtures decrease arthropod herbivoresCrop 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 i fl d bi di itincreases gene flow and biodiversity – Metapopulation theory (Soulé 1987)
Landscape level agrobiodiversityLandscape level agrobiodiversity
HomeTraditional
extensive
Shifting
high
HomeGarden
Compound Farm
ShiftingCultivation
Nomadic Rotational Inter-Pastoralism Fallow
Compound A ib i
cropping
Plantations, O h d
Species Diversity
Agribusiness
IntensiveCereal
P d ti
Orchards
intensive
Production
Multiple Singlelow Field System
p gMcNeely and Scherr 2003
Landscape Configuration and Ecosystem Services
“Land sparing” agriculture:coarse grain, abrupt change
“Wildlife‐friendly” agriculture:fine grain, spatial continuity
Tradeoff model Synergy model
(Slide due to A. Power, from Fischer et al. 2008)
From ecological functioning to ecosystem services
Millennium Ecosystem Assessment (2005) Ecosystems and Human Well Being: Synthesis Island pressand Human Well‐Being: Synthesis. Island press, Washington D.C.
Ecosystem Services statusRegulating Services
Provisioning services
Ecosystem Services status Air quality regulation
Climate regulation – global
Climate regulation – regional andg
Food crops
livestock
Climate regulation – regional and local
Water regulation +/–Erosion regulation
capture fisheries
aquaculture
Erosion regulation
Water purification and waste treatment
Disease regulation +/q
wild foods
Fiber timber +/–
Disease regulation +/–Pest regulation
Pollination
cotton, silk +/–wood fuel
Genetic resources
Natural hazard regulation
Cultural Services
Genetic resources
Biochemicals, medicines
Fresh water
Spiritual and religious values
Aesthetic values
Recreation and ecotourism +/–
Millennium Ecosystem Assessment (2005) Ecosystems and Human Well‐Being: Synthesis. Island press, Washington D.C.
Ecosystem services in agroecosystemsEcosystem services in agroecosystemsPriced in Affects
Supporting services Provisioning
the marketmean output
Supporting services‐Nutrient recycling
‐Photosynthesis‐Pollination
Provisioning services‐Foods, fuels, fibers‐Water yields
Regulating services‐Soil erosion control
‐Genetic material
Cultural services‐Recreation
AgroecosystemsSoil erosion control
‐Pest control‐Hydrological control‐Pollution buffering
Mi li i l
Recreation‐Spiritual renewal‐Aesthetic pleasure‐Sense of placeS i ifi i f i‐Microclimatic control ‐Scientific information
Not priced in the
Affects the variance of in the
marketvariance of output
Biodiversity, ecological functioning and ecosystem services
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 ecosystembenefits 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 pricescomplete markets, perfect information etc) the market prices of ecosystem services will be good measures of their value.
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 valuevalue.
• To understand the social value of agroecosystems we need to• 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……..or costs that lie outside the market……..
• …..plus mechanisms to internalize those benefits or costs (to…..plus mechanisms to internalize those benefits or costs (to ensure that farmers are compensated or penalized).
Spatially distributed agricultural externalities: the downside
L S l R• La Sepultura Reserve– 167 000 ha; buffer zone another
150 000 ha
Sierra Madre de Chiapas, Mexico:Deforestation and erosion
– Tropical forest: deciduous → evergreen cloud forest
– Buffer zone: Heavy extraction of
Deforestation and erosion
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 anddeforestation and slash and burn agriculture.
The ‘dead zone’ in the Gulf of MexicoThe 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.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.
Th d d h d d• The dead zone reached a record size of nearly 9,000 square miles in 2008
Origins of the dead zoneOrigins of the dead zone
Watersheds from which nutrient run‐off most affects the dead‐zonedead zone
…which maps in areas of intensive agriculture
Solutions to the N pollution problem
• The impacts of nitrate pollution on aquatic systems (esp marine systems) is an externality of agricultureis an externality of agriculture
• May be internalized with a tax on N fertilizer to reflect the external cost of nitrate pollution
M i l
Tax rate equal to the marginal external cost of fertilizer
Costs, benefits of N
Marginal net private
Marginal external costs of N
C*
external cost of fertilizer applications (red line)
Constant unit tax rate equal to the
private benefits
C Constant unit tax rate equal to the marginal external cost of fertilizers at the socially optimal level of fertilizer applications (blue line)
N application
Spatially distributed agricultural externalities: the upside
• Positive off‐site externalities from on‐farm land management strategies include a number ofstrategies include a number of cultural services– Provision of habitat for beneficial
species
– Maintenance of valued landscape
R i d i ( k– Recreation and tourism (markets exist)
– A sense of placep
– Satisfaction of cultural need for association with the land
Spatially distributed agricultural externalities: the regulating services
• Many of the most important off‐site externalities relate to the regulatingexternalities relate to the regulating services:– Regulation of water quality and
quantity
– Regulation of soil erosion
Regulation of pest predation– Regulation of pest predation
– Regulation of disease transmission
– Reduced vulnerability to invasive yspecies
– Biocorridor provision mitigates risks to metacommunitiesmetacommunities
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.externalities of market production.
• PES schemes are designed to stimulate transactions in which a an gecosystem 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 y, p y yservice providers or on indirect ecological indicators.
Current status of PES schemesCurrent status of PES schemes
H d d f PES h b i i l d d h• Hundreds of PES schemes are being implemented around the world covering four main ecosystem services: – water provisioning,water provisioning,– carbon sequestration,– landscape amenity, and
bi di i i– biodiversity conservation.
• Most current PES schemes are local level arrangements and• 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 d USA) t ti l l l ( C l bi C t Ri Chiand USA), or at national level (e.g. Colombia, Costa Rica, China
and Mexico).
Payments for ecosystem servicesPayments for ecosystem services
• If l d d t i• If land users do not receive compensation for the production of valuable ecosystem services they willecosystem services, they will not provide them.
PES t lik th• PES systems, like other market mechanisms, induce land managers to incorporate the economic value ofthe economic value of ecosystem services into their financial decisions.
• Their principal attraction is that they enhance efficiency.
PES schemes for water provisionPES schemes for water provision
• PES schemes for water provision exist in all countries shaded green.
PES schemes for agrobiodiversityPES schemes for agrobiodiversity
• Countries implementing schemes for agrobiodiversity are shaded yellow.
Evaluation of the effectiveness of PES schemes
Arriagada R. and C. Perrings (2009) Making Payments for Ecosystem Services Work, Working Paper, UNEP, Nairobi.
Agrobiodiversity conservationAgrobiodiversity conservation
• While there are agrobiodiversity PES schemes, and while agrobiodiversity is a recognised target for some payments under the CAP and other major agricultural policiesunder 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.pp
• In situ conservation of associated species attracts even less.In situ conservation of associated species attracts even less.
Biodiversity conservation priorities by society at present
Hi h P d l/ ildl d• 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• 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?
Protected areasProtected areas
11% f ll l d i i d• 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 conservation`boundaries’ to include
forest‐agriculture ecotones as an inclusive landscape unit
– Increase income from off‐site ecosystem service flows from agricultural landscapes
What should motivate conservation of crop genetic diversity
• Homogenization of production agriculture increases the spatial correlation of riskscorrelation of risks
• In Vavilov megadiversity areas• In Vavilov megadiversity areas farmers are able to manage risk through conservation of crop g pgenetic diversity
• In genetically depauperate areas risks are highly correlated spatially
What should motivate conservation of crop agrobiodiversity more generally
• Agrobiodiversity has an important regulatory function – not just for crop production – but for a range ofcrop production – but for a range of off‐site ecosystem service flows.
• Arobiodiversity also supports important cultural services, and p ,these grow as communities become more urbanized
Optimal conservationOptimal 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 Hotellingagrobiodiversity). The test is due to Harold Hotelling.
• It will be optimal to refrain from converting a resource to• 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 socialThis 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.
Investing in agroecological assetsInvesting in agroecological assets
I f ll h i h ld i i h• It follows that it should pay to invest in the agroecosystemsthat 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) itthe market (because the services are, e.g., public goods) it may be necessary to implement a PES scheme funded through taxation.
The consequence of underinvestment in agroecosystems: Adjusted Net Savingsin Poor Countriesin Poor Countries
25
10
15
20
gs Rate %
High income countries
0
5
10
ed Net Saving
Heavily indebted poor countries (HIPC)Low income countries
-10
-5
Adjuste
Middle income countries
-15
http://web.worldbank.org/WBSITE/EXTERNAL/TOPICS/ENVIRONMENT/EXTEEI/0,,contentMDK:20502388~menuPK:1187778~pagePK:148956~piPK:216618~theSitePK:408050,00.html 35
Concluding remarksConcluding remarks
Whil i d l d i b i• 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.y
• 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 culturalthe core provisioning services, but also for many cultural services, and for the regulating effects of farm systems on water quality and quantity.
AcknowledgementsAcknowledgements
• DIVERSITAS Agrobiodiversity Network (Louise Jackson)
• Alison Power
• NSF BESTNet Project