How the ecosystem service concept can help make better

decisions

Bob Scholes

CSIR Natural Resources and EnvironmentUniversity of the Free State, 3 Feb 2012

Biodiversity or ‘Life on Earth’

Ecosystem Services‘the benefits people derive from Nature’

MA 2005 Ecosystems and human wellbeing: a framework for assessment Island Press

Human wellbeing

Material needs

Social relations

Health

Security

Freedoms & choice

A slightly modified version

Scholes et al 2010 Assessing State and trends in ecosystem services and human wellbeing. Ecosystems and Human wellbeing: A manual for practitioners. Island Press

Stocks and flows

• Ecosystem services are always flows – they have units of quantity per unit area per unit time

• The underlying resource that allows the flow to be delivered may be a stock, measured in quantity per unit area

• For example, the stock of carbon in the soil and vegetation may reach hundreds of tonnes per hectare, but it has no value…changes in the stock do. If they represent flows from the atmosphere into the land, they have a value of around R800/tonne

Bundles and simplificationsHypothesis: in any given land use most of the value is

represented by just a few services

Can you put a value on Nature?Specifically, can and should we assign a Rand value?

• A ‘common currency’ makes tradeoffs and optimisation explicit and possible to build into the price

• ‘Money talks’ – persuasive measures for development funders

• Facilitates inter-study comparisons

• Ethical questions – what is the value of a life or a species?

• Non-market services (eg the value of a view) require indirect methods which may be very unreliable

Total Economic Value has many partsScholes, RJ et al 2001 Ecosystem services and human wellbeing: A handbook for Practitioners. Ed Ash, N et al Chap4 Island Press

Total economic value often goes down with ecosystem transformation for ‘development’

– Why does this apparently irrational behaviour occur?• because private financial

benefits are often greater in the converted system, while the public costs increase even more

The ‘Natural Capital’ approach

• Natural capital is a consistent way of converting diverse flows of ecosystem services into common-metric stocks, which can be added to other measures of wealth, such as Manufactured Capital or Human Capital, to give ‘Inclusive Wealth’

• Natural Capital is the net present value of the future yields of ecosystem services

• It is a useful conceptual way of quantifying the effects of degradation

Arrow,K, P Dasgupta,L Goulder, G Daily, P Ehrlich,G Heal, S Levin, K-G Maler,S Schneider, D Starrett and B Walker 2004 Are We Consuming Too Much? Journal of Economic Perspectives 18 (3): 147–172

Despite economic growth,Africa is getting poorer

Inclusive wealth = Manufactured capital+Human Capital+Natural CapitalArrow,K, P Dasgupta,L Goulder, G Daily, P Ehrlich,G Heal, S Levin, K-G Maler,S Schneider, D Starrett and B Walker 2004 Are We Consuming Too Much? Journal of Economic Perspectives 18 (3): 147–172

Real savings,corrected for

resource depletion,

are negative

Millennium Ecosystem Assessment 2005Ecosystems and Human Wellbeing: Synthesis

Scholes, RJ 2009 Syndromes of dryland degradation in southern Africa. AJRFS 26, 113-125

Using natural capital todefine and quantify

degradation

Degradation of ecosystem services causes loss of value

– Degradation tends to lead to the loss of non-marketed benefits from ecosystems

– The economic value of these benefits is often high and sometimes higher than the marketed benefits

Timber and fuelwood generally accounted for less than a third of total economic value of

forests in eight Mediterranean countries.

You don’t strictly need to bring everything to common metrics….

…for tradeoff analysis, it is only necessary that you be able to quantify the service yield, in its own metrics, relative to a common measure of intensity of use

It is the shape of this function that matters most

Non-monetary metricsexample: greenhouse warming potential

1 t CO2 = 1/25 t CH4 = 1/298 t N20 ~ a few picoWatts/m2

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Rangefed Feedlotted

Production system

kgC

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CO2 from feed production

Manure CH4

Enteric CH4 finishing

Enteric CH4 juveniles

Enteric CH4 breeding stock

Fire

Land use intensification exampleBalmford, A., R. E. Green, and J. P. W. Scharlemann. 2005. Sparing land for nature: exploring the potential

impact of changes in agricultural yield on the area needed for crop production. Global Change Biology 11:1594–1605.

Phalan, B et al 2011 Reconciling Food Production and Biodiversity Conservation: Land Sharing and Land Sparing Compared Science 333: 1289-1291.

Pre-cultivation biodiversity

Level of agricultural inputs

Bio

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rsity

Cro

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Conclusion: if you want to have a given level of agriculture, but protect as much biodiversity as possible, it is often best to have intensive agriculture on a limited area

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Degree of intensification

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Area converted

Ag inputs/area

Crop yield

In reality, intensification involves both area expansion and increased inputs per area, and they have different

consequences for biodiversity on- and off-site

Crop area * yield per area

Progressively more marginal land needs more inputs

Constructing the agricultural output curve

intensification

Area cultivated Inputs per area

Agricultural output

Building up the biodiversity loss curve

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Degree of intensification

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Biodiv index

Fragmentation

Nutrient leakageintensification

Area cultivated Inputs per area

Habitat loss Fragmentation Nutrient leakage

Freshwater biodivloss

Terrestrial biodivloss

Biodiversity Index

Relative responses to a shared fundamental driver

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Biodiv index

The independent axisneeds to be shared

The dependent axes do notneed to be in common units

Look at the differentials and their ratios

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Degree of intensification

dB/di

dC/di

dC/dBA B

Likely rangeNice, but doesnot meet theminimum foodproduction target

Marginal food gainsfor major off-site biodiversity impacts

Have lost much biodiv, so you may as well intensify

Is biodiversity per se an ecosystem service?

• In my opinion, generally no, with the following exceptions:– Where the biodiversity itself is the reason for tourism

• Specialist birdwatchers• Botanical tourists

– Indirectly, where biodiversity enhances a supporting service (eg primary production, pollination) or a regulating service (eg constancy of production, or suppression of pest outbreaks)

• Individual elements of biodiversity clearly provide services– All domesticated species and wild-harvested resources