This document summarizes a study that estimated the conservation value of open space nature preserves in Wake County, North Carolina by quantifying the ecosystem services they provide. The study identified properties containing important ecological resources and habitats. It then measured benefits from ecosystem services including carbon sequestration and storage, nutrient retention, biodiversity and wildlife habitat protection, and wildlife-associated recreation. The total annual ecosystem service value across the study area was estimated to be over $226 million. The properties providing the highest per hectare benefits varied depending on the ecosystem service.

1. Estimating the Conservation Value of
Open Space Nature Preserves
Aimee Schmidt
North Carolina State University
March 2012

2. Project Objectives
Identify conservation quality properties containing
exceptional features of significant ecological value
Quantify benefits offered through a portfolio of
ecosystem services
Identify
 habitat of conservation concern
 high quality and rare natural communities
 significantly rare, threatened or endangered species

3. Presentation Sequence
Open Space Property Selection
Ecosystem Service Benefits
Regulation of Climate: carbon sequestration
Water Purification: nutrient retention
Biodiversity: habitat provisioning
Wildlife-associated Recreational Opportunities
Summary of Ecosystem Service Benefits
Insight and Observations

4. Study Area:
Property Selection
Wood Ducks (Triangle Delta Waterfowl photo)

5. Definitions
Publicly Managed Open Space is protected land owned and
managed in the public interest to
 protect water quality
 preserve natural resources
 manage production of resources (forest and farmland)
 preserve historic and cultural property
 protect scenic landscapes and outdoor recreation opportunities
 protect public health, safety and welfare
Element Occurrences are rare species and habitat suitable to
conserve endangered species
Significant Natural Heritage Areas identify land and water
resources important for the conservation of biodiversity that
generally contain Element Occurrences

6. WakeNature Preserves Partnership
MISSION
Provide resources to identify ecologically valuable, publicly owned
open spaces within Wake County, NC and build capacity for appropriate
management and long-term stewardship.
GOALS
• Identify and designate as “WakeNature Preserves” protected open
spaces containing important ecological or geological resources
• Create public awareness and appreciation of our highest quality
natural areas
• Conduct natural resource inventories and develop management plans
for Preserves
• Develop an organized volunteer base of citizen-scientists to monitor
Preserves

7. Study Area Selection Criteria
• Publicly managed open space in Wake County
• Contiguous parcels >16.2 ha (40 ac)
• Property designated as Significant Natural Heritage Area
• Extant Element Occurrences seen since 1985
• Conducive to enjoying and learning about
nature in a contemplative, natural setting

8. Study Area
39 properties — 14,175 ha
• 12,655 ha terrestrial habitat
• 1,214 ha forested wetlands
• 306 ha aquatic habitat

9. Properties of Interest to WakeNature
included in the Study Area
Anderson Point Park Lake Myra Open Space
Hemlock Bluffs Lake Raleigh Woods
Horseshoe Farm Park Marks Creek Open Space
Lake Johnson Open Space Mitchell Mill Park

10. Climate Regulation:
Sequestration and
Storage of Carbon
Piedmont Beech Natural Area, Umstead Park
(National Park Service photo)

11. Definitions
Sequestration refers to the annual rate
carbon is stored in an ecosystem over
time
Storage represents the mass of carbon
held in an ecosystem at any given
point in time
Social Cost of Carbon (SCC) reflects
the price of economic damage caused
by releasing additional carbon into the
atmosphere CNBC photo

12. Method for Measuring Benefits of
Carbon Sequestration and Storage
Sequestration benefit = Ton-C in A-G biomass ∙ Area ∙ SCC
landcover class
Storage benefit = ∑ Ton-C in 4 carbon pools ∙ Area ∙ SCC
landcover class
Model: InVEST, v 2.0
Datasets: SEGAP Landcover (’01), NHP SNHA-EO (‘11), Wake Open Space (‘10)

13. Carbon Sequestered in the Study Area
144,617 tons (annual est.)
$ 8,677,016 in damage
avoided @ $60/ton
Highest value per hectare:
Falls Lake Recreation Area
Wake County Open Space
Crabtree Greenway
Tobacco Trail

14. Carbon Sequestered on Properties of Interest
(normalized)
$1,000 18
$900 16
$800
14
$700
12
$600
10
Ton-C/Ha
SCC/Ha
$500
8
$400
6
$300
4
$200
$100 2
$0 0
Lake Myra Hemlock Horseshoe Mitchell Mill Marks Creek Anderson Lake Lake Raleigh
Open Space Bluffs Farm Park Park Open Space Point Park Johnson Woods

15. Carbon Stored in the Study Area
2,170,264 tons (est.)
$ 130,215,840 in damage
avoided @ $60/ton
Highest value per hectare:
Falls Lake Recreation Area
City of Raleigh Greenway
Underhill mitigation
Drewry Hills Park

16. Carbon Stored on Properties of Interest
(normalized)
$14,000 250
$12,000
200
Social cost of carbon per hectare
$10,000
Ton-C per hectare
150
$8,000
$6,000
100
$4,000
50
$2,000
$0 0
Hemlock Lake Myra Mitchell Mill Horseshoe Marks Anderson Lake Lake
Bluffs Open Park Farm Park Creek Open Point Park Johnson Raleigh
Space Space Woods

17. Water Purification:
Nutrient Retention
Marks Creek (George Hess photo)

18. Definitions
Replacement cost estimates ecosystem
service value by measuring the cost of
filtering and chemically treating water to
meet quality standards
Nutrient export is excess nutrient runoff
influenced by slope and landcover class
Nutrient retention reflects filtration efficiency
of landcover (plants and soil)
Water treatment costs reflect EEP offset
rates applied to excess nitrogen and
phosphorus reaching surface water in the
Neuse and Cape Fear watersheds

19. Sub-watersheds Transecting the Study Area

20. Method for Measuring Benefits of
Nutrient Retention
Retention Benefits = ∑HP (kg of net retention)HP ∙ treatment cost($)
sub-watershed
where the net retention of each nutrient is summed as it makes its way down the
hydrologic pathway (HP) to the pour point in each sub-watershed.
Model: InVEST, v 2.0
Datasets: SEGAP Landcover (‘01), USGS Hydrology (‘11), NRCS Soil (‘06),
Precipitation (‘71-’00), Evapotranspiration (‘04), NHP SNHA-EO (‘11),
Wake Open Space (‘10)

21. Nutrient Retention in the Study Area
22,064 Kg of nitrogen retained
5,012 Kg of phosphorus retained
Annual benefits of:
$ 899,329 @ $ 40.76/kg (nitrogen)
$ 1,569,354 @ $ 313.10/kg (phosphorus)
Most valuable properties per hectare:
Anderson Point
Falls Lake Recreation Area
Little River Open Space
Lake Myra Open Space
Upper Tar Guthrie (NCEEP photo)

22. Nitrogen Retention in the Study Area

23. Phosphorus Retention in the Study Area

24. Nutrient Retention on Properties of Interest
(normalized)
$350 9.0
8.0
$300
7.0
$250
Nutrient retention
6.0
Replacement cost
$200 5.0
$150 4.0
3.0
$100
2.0
$50
1.0
$0 0.0
Anderson Point Lake Myra Mitchell Mill Horseshoe Hemlock Bluffs Lake Raleigh Marks Creek Lake Johnson
Park Open Space Park Farm Park Woods Open Space Open Space
Nitrogen Retention Benefit ($/ha) Phosphorus Retention Benefit ($/ha)
N Retained (Kg/ha) P Retained (Kg/ha)

25. Biodiversity:
Habitat Protection

26. Protected Plant and Animal Habitat
within the Study Area
12 45%
40%
10
35%
Share of EOs Countywide
8 30%
Number of EO's
25%
6
11 20%
4 15%
6 10%
5 5
2 4
5%
0 0%
Significantly Threatened Endangered High quality Species of
rare species species species resources special
[DOT] concern
State Protection Status
Source: NC Natural Heritage Program ( August 2011)

27. Extant Species’ Habitat in the Study Area
Protection Status Property
Significantly Mitchell Mill Park (2);
rare Lake Johnson (1)
Threatened Mitchell Mill Park (2)
Marks Creek (1);
Endangered
Mitchell Mill Park (2)
High quality
Mitchell Mill Park (2)
(imperiled)
Special concern Mitchell Mill Park (1)
Source: NC Natural Heritage Program
( August 2011)

28. Definitions
Contingent Valuation (CV) measures
existence value by eliciting statements about
willingness to pay for specific ecosystem
services based on hypothetical scenarios
Existence Value is placed on simply knowing
something exists even if you will never see or
use it
Benefit Transfer is the adaptation of economic
data from study sites under certain resource
and demographic conditions to a site with
similar characteristics
Consumer Surplus is the monetary difference
between actual price paid and the maximum
one would have been willing to pay

29. Method for Measuring Benefits of
Biodiversity through Habitat Protection
WTP = Δ Service Q, Substitute/compliment, Site characteristics, Research procedure
Aquatic Habitat Benefit = 𝒆 MHI + Baseline WQ + Δ Fish population ∙ Households
Δ WQ(spp.)
Terrestrial Habitat Benefit = 𝒆 Area + CV(OS + spp. habitat)
Wetland Service Benefits = Service ∙ 𝒆 MHI + Area + CV(service)
Species’ Preservation Benefit = +Δ (spp.)+ CV(bird spp.) ∙ Households
Model: Defenders of Wildlife Habitat Estimation Toolkit , v1.0
Datasets: SEGAP Landcover (‘01),NHP SNHA-EO (‘11),US Census (‘10), Wake Open Space (‘10)

30. Habitat Protection
Willingness to pay to protect aquatic and terrestrial
habitat to ensure species’ survival
Willingness to pay to increase a bird species’
population through habitat protection
RCW (Steve Allen photo)
Protection Annual Value
Aquatic habitat $ 22,327,620
Terrestrial habitat 603,285
10% increase in bird species’ population 17,610,138
Benefits of Habitat Protection $ 40,541,043

31. Forested Wetlands in the Study Area
Ecosystem Share of
Annual Value
Function Total Value
Bird watching opportunities $ 2,351,518 48%
Water purification 1, 682,604 34%
Habitat provisioning 428,542 10%
Flood prevention 303,500 6%
Amenity 106,832 2%
Wetland Service Value $ 4,872,966
Little River (NC Div of Water Quality photo)

32. Biodiversity:
Wildlife-associated
Recreational
Opportunities
Umstead Park (Aimee Schmidt photo)

33. Definitions
Travel Cost Method assumes value is
reflected in how much people are willing
to pay to travel to a site
Consumer Surplus measures enjoyment
received from visiting a site or knowing
that a species exists.
Economic Impact represents dollars
spent by visitors that ripple through local,
regional and state economies generating
additional sales, income and employment

34. Method for Measuring Benefits of
Biodiversity through Recreational Opportunities
Wildlife-viewing Activity Days = 𝒆 Area + MHI + Wake residents
Daily Viewing Value = Trip expenses + c. surplus + Economic impact
Visit
Recreational Benefits = Daily Viewing Value ∙ Wildlife-viewing Activity Days
Model: Defenders of Wildlife Habitat Estimation Toolkit , v1.0
Datasets: SEGAP Landcover (‘01), NHP SNHA-EO (‘11), US Census (‘10),NHP SNHA-EO (‘11),
Wake Open Space (‘10)

35. Wildlife-associated Recreation
in the Study Area
Wildlife-viewing activity days 715,037
Daily economic impact and
WTP for wildlife viewing $ 55
Annual Recreation Benefit $ 39,327,035

36. Ecosystem Service
Portfolio Summary
Cheryl Harner photo

37. Ecosystem Service Benefits in Study Area
Nitrogen Retention $899,313
Phosphorus Retention $1,569,354
Carbon Sequestration $8,677,016
Wildlife-associated Recreation $39,327,035
Wildlife Habitat Protection $45,414,039
Carbon Storage $130,215,840

38. Insight and
Observations
White-tailed Deer (Photo by Steve Allen)

39. Costs that quantify service benefits
social
economic
regulatory
Valuation methods
direct market transactions
net willingness to pay
Ground-truth data
geo-spatial imagery
scientific research
Barred “hoot” owl (Photo by Jody Hildreth)
benefit value transfer

40. Acknowledgments
Committee members Dr. Bob Abt, Dr. George Hess and
Dr. Toddi Steelman
Technical assistance from Curtis Belyea, Rich Gannon,
Dr. Alexa McKerrow, Mike Templeton, Dr. Heather Cheshire,
Manu Sharma and Stacie Wolny
John Finnegan, NC Natural Heritage Program
Michael Kirschman, Nature Preserves & Natural Resources,
Mecklenburg County Park & Recreation

41. Thank
you
Crow and Hawk (Photo by Steve Allen)

42. Geospatial Data Resources
Data Date Agency
1997- Prism Climate Group, Oregon State University
Precipitation
2001 http://www.prism.oregonstate.edu.
Food and Agriculture Organization of the United Nations
Evapotranspiration 2004
http://www.fao.org/geonetwork/.
Biodiversity & Spatial Information Center, USGS NC Cooperative
NC SEGAP Landcover 2001 Fish & Wildlife Research Unit, NCSU.
http://www.basic.ncsu.edu/segap/
Wake County Public Open
10/10 Wake County GIS Department wakegov.com/gis
Space
Open Space - NHP SHNA Datasets compiled by Dr. Cheshire's GIS class (Spring 2008 ) to
2008
and EO intersection assess potential natural areas in Wake County. WakeNature wiki
Significant Natural NC DENR, Div. of Parks and Recreation, Natural Heritage
2008
Heritage Areas Program, Raleigh, NC. nconemap.org
Natural Heritage Element NC DENR, Div. of Parks and Recreation, Natural Heritage
Occurrences 8/11
Program, Raleigh, NC nconemap.org
Biodiversity & Spatial Information Center, USGS NC Cooperative
HUC-10 Watersheds 2008
Fish & Wildlife Research Unit, NCSU. http://www.basic.ncsu.edu
Digital Elevation Model United States Geological Survey 10-meter National Elevation
4/11
(DEM) Dataset. http://seamless.usgs.gov
Soil Survey Staff, NRCS. March 2003 soil survey geographic
Soil Depth and Plant
2006 (SSURGO) database for Wake County, NC
Available Water Content
http://soildatamart.nrcs.usda.gov