SOIL'S ROLE IN RESTORING ECOSYSTEM SERVICES
AN ECOSYSTEM SERVICES APPROACH TO THE EVALUATION OF SOIL CONSERVATION POLICY IN NEW ZEALAND HILL COUNTRY
Estelle Dominati, Alec Mackay, March 2014 SOILS: A FINITE RESOURCE GETTING SCARCER EVERYDAY
Misconception: NZ is blessed with large areas of versatile and elite soils
→ 5.2 % High class soils (LUC 1&2 – 14.4% if add LUC 3)
Challenging Government Goals: • Double exports earning by 2025 • Cut emissions to the environment by half • Increase well-being of kiwis Greater demands on the environment
High demand for a holistic value for Land: Assess the multi-functionality of land to achieve sustainability.
Ecosystem services approach future of resource management Ecosystem services = “direct and indirect contributions of ecosystems to human well-being” (TEEB, 2010) Hawke’s Bay coastal zone SOIL CONSERVATION
Damage from April 2011 storm: 43 km2 (4300 ha) of bare ground from a total area of 5900 km2
GNS science, Jones et al., 2011 LOCALISATION OF DAMAGE
Land Use Capability 1 2 3 4 5 6 7 8 other Total class
Area in Sheep 1,661 6,100 39,467 20,026 3,764 207,979 65,588 3,985 1,624 348,569 & Beef
Area lost to 4.7 24.4 109.7 54.3 25.5 2,156.7 1,341.3 503.8 2.9 4,220 erosion
Bare ground (% of total land 0.3% 0.4% 0.3% 0.3% 0.7% 1.0% 2.0% 12.6% 0.2% NA in that LUC)
Bare ground (% of total area 0.1% 0.6% 2.6% 1.3% 0.6% 51.1% 31.8% 11.9% 0.1% 100% lost)
94.8% SOIL CONSERVATION
COSTS OF THE APRIL 2011 STORM TO HAWKE’S BAY REGIONAL COUNCIL: NZ$ 39 million = infrastructure, land, personal and commercial damage claims
BROADER ENVIRONMENTAL COSTS? USE AN ECOSYSTEM SERVICES APPROACH • Loss of ecosystem services from landslides? • Recovery of the provision of ES ? • Impact on the provision of ES of Soil Conservation practices • Cost Benefit Analysis of an investment in soil conservation (wide-spaced trees) SOIL NATURAL CAPITAL SOIL ECOSYSTEM SERVICES
Soil Degradation Cultural Services Inherent Properties Self-actualisation •Depth Needs Degradation •Clay types Processes •Texture •Wetness class Esteem needs •Erosion •Compaction Regulating Services
Social needs Supporting Human Processes Manageable Needs •Nutrient cycling Properties •Water cycling •Mp Safety and security •Soil biological activity •OM needs •N and P Provisioning Services
•pH Physiological needs Soil Formation and Maintenance
External Drivers
Natural & Anthropogenic Key: Climate, Land use Stocks Flows
Processes Dominati E, Patterson M, Mackay A (2010) A framework for classifying and quantifying the natural capital and ecosystem Drivers services of soils. Ecological Economics, 69(9), 1858-1868. IMPLEMENTATION OF THE FRAMEWORK
1 MODELLING OF SOIL RECOVERY AND SOIL CHANGE WITH MANAGEMENT: • Typical Sheep and Beef farm of Hawke’s Bay • Follow soil properties recovery after erosion, • Follow soil properties of pasture planted with wide-spaced poplars
2 QUANTIFICATION OF THE SOILS SERVICES : • Flows /ha/yr • proxies to measure each service = focus on part played by the ecosystem • Use of OVERSEER® nutrient budget to calculate proxies
3 ECONOMIC VALUATION OF ES: Economic value of each soil service in NZ$/ha/yr. Techniques used: Market prices, Replacement costs, Provision costs, Defensive expenditures FARM CHARACTERISTICS AND SOIL PROPERTIES
Block 1 Block 2 Land Use Capability 1-5 6-8 classes Stocking rate (SU/ha) 13 8 Area (ha) 255 (45%) 315 (55%) Waimarama sandy Wanstead clay loam Soil type loam (sedimentary, (recent, pallic) brown) Olsen P 25 16 Anion Storage Capacity 43 21 N fertiliser applied 20 0 (kgN/ha/yr) P fertiliser applied 20 15 (kgP/ha/yr)
Analysis done on Block 2 = 95% of damage and 100% of conservation ECOSYSTEM SERVICES FROM SOIL AND TREES PROVISIONING SERVICES: • Provision of food (pasture quantity and quality) • Provision of food: Tree foliage • Provision of fibre: Wood • Provision of physical support to human infrastructures and animals • Provision of shade and shelter to farms animals from trees
REGULATING SERVICES: • Filtering of nutrients (N and P) and contaminants • Flood mitigation • Recycling of wastes and detoxification • Carbon storage in soil • Carbon storage in trees
• Regulation of N2O and CH4 emissions • Biological control of pests and diseases
CULTURAL SERVICES: • Aesthetic experience • Recreation • Cultural uses • Spiritual enrichment (Earth sacredness) FODDER FROM TREES
1 QUANTIFICATION:
• Estimate the amount of foliage dry matter depending on tree age and density (stems per hectare) Kg DM/ha
2 VALUATION:
• Use the market price of pasture dry matter ($0.14/kgDM) Value of fodder from trees (NZ$/ha/yr) FLOOD MITIGATION 1 QUANTIFICATION:
• Quantify the service with OVERSEER : Rainfall (RF) - Runoff (RO) Water stored by the soil (mm/ha/yr)
Flood mitigation RF service
RO
2 VALUATION: • Use the provision cost method. • Calculate the maximum amount of water stored by the soil for 7 consecutive days • Calculate the size and annualised costs of dams needed to stored that water on farm. Value of flood mitigation (NZ$/ha/yr) METHODOLOGY Three situations over time:
• Uneroded soil: actual management • Eroded soil: follow ES provision during soil recovery • Wide spaced trees: what happens to ES under wide spaced poplars
Soil Properties Provision of Value of & Soil Change Ecosystem Services Ecosystem Services over time RECOVERY Pasture OF SOIL production semi- PROPERTIES permanently reduced by 20%
Rosser B.J., Ross C.W. (2011) Recovery of pasture production and soil properties on soil slip scars in erodible siltstone hill country, Wairarapa, New Zealand. New Zealand Journal of Agricultural Research 54:23-44. TRENDS OF RECOVERY OF ES AFTER EROSION – NO TREES
200%
180% Food Quantity 160%
140%
Flood mitigation 120%
100% Filtering of nutrients and contaminants 80%
% of uneroded level uneroded of % Net Carbon accumulation 60% (10-100 cm)
40% Regulation of pests and 20% diseases populations
0% 0 20 40 60 80 100 120 Years after the erosion event Results of the Economic Valuation & Cost-Benefit Analysis VALUE OF ES BEFORE AND AFTER EROSION – NO TREES
6000 Total value Block 1 Block 2 5000 Eroded block 2 20 years after 50 years after
4000
3000 $/ha/yr
2000
1000
0 Total value ($/ha/yr) Provisionning services Regulating services
Value of the flows of Ecosystem services NOT the Natural Capital stocks Value of regulating services is greater than value of the provisioning services Recovery non linear: rapid between years 1-20, then slows down VALUE OF ES – WITH AND WITHOUT TREES
6000 Block 1 Block 2 Above standard Blok 2 Eroded (Y0) 5000 pasture Trees (Y10) Trees (Y20)
4000
3000 Above eroded levels $/ha/yr
2000
1000
0 Total value ($/ha/yr) Provisionning services Regulating services NET PRESENT VALUE OVER 20 YEARS ($/ha)
30% less than B1 $90,000 Extra 10% with trees $80,000 56% permanently lost $70,000 with erosion
$60,000
Uneroded pasture - $50,000 Block 1 Uneroded pasture -
$40,000 Block 2 NPV in $/ha in NPV Trees on Block 2 $30,000 Eroded Block 2 $20,000 recovering
$10,000
$- 3% 5% 10% Discount rate $1 in soil conservation $68 NPV added services + avoided costs
BENEFIT COSTS ANALYSIS Four scenarios for Block 2: • Option1: Trees not harvested - Services not considered • Option 2: Trees harvested - Services not considered • Option 3: Trees not harvested - Services considered • Option 4: Trees harvested - Services considered
Method: • For each scenario, look at costs and revenues for each year • The value of ES (net Δ) is a benefit, usually NOT considered in BCA • Calculate the NPV over 20 years (4 discount rates) BCA OF 4 MANAGEMENT OPTIONS, FOR 4 DISCOUNT RATES
12000 Option1 = Trees not harvested - Services not considered Option 2 = Trees harvested - Services not considered
10000 Option 3 = Trees not harvested - Services considered
Option 4 = Trees harvested - Services considered 8000
6000
4000
2000 Net present value /ha over 20 years 20 over /ha value present Net
0
-2000 0% 3% 5% 10% Discount rate CONCLUSIONS The Ecosystem Services approach can: • Give new insights into the current use of our natural resources • Focus on performance of the ecosystem under specific combination of land use and management • Holistic approach to the value of land including trade-offs between social, economic and environmental aspects • Guide future investments in Ecological Infrastructure for policy (incentives?)
In New Zealand: • NC/ES used for a NEA for environmental reporting • Include ES in regional plans - • Use NC approach for limit setting for NO3 leaching
Thank you!