Means-Ends Exercise: Great Dismal Swamp Example
MEANS-ENDS DIAGRAM DEVELOPMENT SMALL GROUP EXERCISE A
Created by: Christy Ihlo, Nicholas Institute for Environmental Policy Solutions at Duke University
Description of Exercise
The goal of this exercise is to experiment with developing means-ends diagrams. Via email, you received
background information for each of those examples and each table is assigned one of the examples
(noted on the index card in the center of the table). One copy of background materials has been
provided per table.
Use the background materials to diagram ecological changes driven by the given management option
and their connections to ecosystem services.
Getting Started: An Example Generic Means-Ends Diagram
For each example, the management alternative is given. Some ecosystem services are noted in the
background information. However, your diagram should not be limited to the services given. Also,
remember that ecological changes includes structures (e.g., forest or wetland structure, but also things
like the soundscape or viewscape of an area), processes (e.g. evapotranspiration, filtration, erosion), and
conditions (e.g., air or water quality).
Means-Ends Exercise: Great Dismal Swamp Example
Example: Great Dismal Swamp National Wildlife Refuge
Located on the border of northeastern North Carolina and southeastern Virginia, the Great Dismal
Swamp provides ecosystem services to a population of more than 1.6 million in the adjacent Virginia
Tidewater metropolitan area. These services include (but are not limited to) recreation opportunities
such as hunting and wildlife watching and carbon sequestration.
The natural landscapes and hydrologic functioning of the Swamp have been significantly altered over
the last several hundred years. These alterations, combined with natural stressors like climate change,
have created multiple challenges for the ecosystem. Some of these challenges extend beyond the
borders of the refuge, such as an increase in severe wildfire events, with smoke impacts over a wide
area. The FWS is working to restore the natural hydrology of the Swamp ecosystem in an effort to
restore the Swamp’s biological diversity, but also recognizes that doing so can benefit a number of
additional ecosystem services.
Task: Create a means-ends diagram using the management objective of hydrological restoration to
map the connections between restoring hydrology and the provision of ecosystem services.
The immediate goal of restoring hydrology is to “sustain or improve viability of wetland communities
and their associated wildlife species.” For example, restoring seasonal flooding of forests supports
nesting and brood habitat for migratory waterfowl (e.g. wood ducks). Monitoring surface flooding
conditions to assure that conditions are favorable to ground foraging neotropical migratory birds
supports refuge and agency objectives and maintaining higher ground water levels within Atlantic white
cedar forest supports restoration and maintenance of this rare habitat.
Water levels and flow can be altered using water control structures that are present throughout the
Swamp. The Refuge can employ a number of strategies to restore hydrology including conserving water
in certain areas, monitoring surface flooding conditions, and maintaining ground water at appropriate
levels. Any of these strategies can alter the overall flow regime of the Swamp, changing many factors
like the frequency of inundation in certain areas, the soil depth to the water table, and the amount of
exposed peat.
Getting Started
• Read the following short sections of the document “Incorporating Consideration of Ecosystem
Services into Plans for the Great Dismal Swamp National Wildlife Refuge” (provided and also
available online at https://nespguidebook.com/cms/wp-content/uploads/2014/11/FRMES-CE-5FULL-PDF.pdf ), paying particular attention to notes about ecosystem services and how they relate
to hydrology:
o Introductory paragraphs and Management Challenges (p. 2-3)
o Weighing Tradeoffs (p. 4-5)
o Options (p. 5)
• Based on those sections, make a list of ecosystem services and write those on the far right side of
the paper.
• Write the management objective on the far left side of the paper.
• Consider the first service in the list. How could changing hydrology affect the provision of this
service? What ecological changes would occur because of that alternative? Think about different
Means-Ends Exercise: Great Dismal Swamp Example
•
•
•
•
ecosystem structures, such as forest or wetland; processes, like how water moves through the
system, erosion, or evapotranspiration; and conditions, such as air or water quality. (If the
connection between the service and hydrology is not apparent, start with another service.)
What indicators could be used to measure those ecological changes?
What additional services do those ecological changes affect? (It may be helpful to think about how
specific indicators may relate to ecosystem services.) Could those services be affected by other
ecological changes?
Continue this iterative process of identifying ecological changes/indicators and services until the
group feels that most of the interactions have been captured. Additional information on the
hydrology and ecology of the Swamp is summarized on the next couple of pages and will be helpful.
Some important things to remember:
o The process of creating the diagram may identify additional services that were not on the
original list.
o Not all services originally listed may be affected by hydrological restoration.
Links to additional background information:
• The full Comprehensive Conservation Plan (CCP) can be found at
http://www.fws.gov/uploadedFiles/Region_5/NWRS/South_Zone/Great_Dismal_Swamp_Complex/
Great_Dismal_Swamp/FinalCCP_GDS.pdf .
• For more information about the refuge, see
http://www.fws.gov/uploadedFiles/Region_5/NWRS/South_Zone/Great_Dismal_Swamp_Complex/
Great_Dismal_Swamp/GDSNWRgeneral.pdf .
Background on Ecology/Hydrology (summarized from the CCP)
Hydrology in the Great Dismal Swamp
Water Dynamics
• Direct precipitation is a major source of water, accounting in part for the fact that more water flows
out of the refuge than enters it as surface inflow in the form of stream and sheet flow from the west
along the Suffolk Scarp.
• Evapotranspiration accounts for the biggest portion of water removal from the swamp ecosystem. It
exceeds rainfall during the growing season and causes a lowering of water levels in the refuge
throughout the summer. The rate of transpiration is not known.
• Surface water runoff through the swamp is also a major means of outflow. Historically, much of the
winter discharge within the swamp was in the form of sheet flow. During low flow periods, the
water would follow the random channels cut during high flow.
• Over the last two centuries natural outflow patterns have been altered; most surface water now
drains through the refuge in the network of canals and ditches with minimal sheet flow.
• Ground water discharge is a secondary output event. Wherever the upper layer confining the
shallow aquifer is absent, ground water wells up into the overlying peat and is discharged from the
peat by evapotranspiration. Ground water is also discharged by seeping directly into Lake
Drummond. Where the aquifer is breached, groundwater is discharged from the refuge as surface
flow through outlet channels that are left uncontrolled.
Means-Ends Exercise: Great Dismal Swamp Example
Current hydrologic setting
• The amount and rate of annual surface inflows into the refuge have increased due to upland land
use practices such as field tiling, road building, and housing along the Suffolk Scarp.
• Water that used to recharge the shallow aquifers and enter the swamp as much delayed ground
water, is now intercepted and diverted into the refuge as surface water.
• This increase in the volume of surface water contributes to higher surface water levels during winter
and storm events and may be in part responsible for reduced volumes of water to recharge the
swamp during dry summer periods.
• The effects of the roads on ground water are not clearly understood, but it is assumed that
associated soil disturbance, compaction, and addition of outside materials to swamp soils have
significantly altered historical patterns of ground water movement through the swamp.
• Surface water levels and the ground water table are highest from December through April and
lowest from May through November.
• Previous owners (prior to acquisition by FWS) installed 115 water control devices and culverts over
the years. Many of the structures deteriorated over time, but the Service has repaired or replaced
most of the critical water control structures since the refuge’s establishment. These control
structures have reduced water losses in the swamp.
Ditches
• The 158 miles of canals and ditches with their attendant spoil bank roads have combined to form
the single most significant alteration to the swamp’s water regime.
• Many of the refuge’s ditches form a network that channels much of the current surface flow into
Lake Drummond, which in turn drains into the Feeder Ditch through a gated spillway and then into
the Dismal Swamp Canal.
• The Dismal Swamp Canal has had a powerful effect on the hydrology of the swamp. The canal
intercepts a majority of the surface water flowing out of the swamp and has breached the artesian
aquifer. Lake Drummond is the primary source of water to operate the canal. Water flow through
the canal is managed by locks at either end of the canal and by the spillway on Feeder Ditch at Lake
Drummond.
Chapter 3
Characteristics of Key Habitats
Peatland Atlantic White Cedar Forests.
• Atlantic white cedar stands are found on deep organic soils where the surface has become elevated
above the water table.
• The vitality of cedar is severely reduced if it is subjected to surface flooding during the growing
season.
• Atlantic white cedar has been harvested in the swamp since the 18th century when the Dismal
Swamp Land Company began operations.
• Loggers usually cut the Atlantic white cedar but left hardwoods to take over the site, or left so much
slash on the ground that Atlantic white cedar seedlings were unable to develop in such shaded
conditions. Other important factors in the gradual succession of Atlantic white cedar stands to
hardwoods include suppression of wildfire and changes in the swamp’s water regime.
Means-Ends Exercise: Great Dismal Swamp Example
Non-Riverine Swamp Forests (cypress-gum and maple-gum)
• Cypress-gum forests are typical southern swamp communities adapted to surface inundation (hydric
conditions) for at least part of the growing season. The association covers 12% of the refuge,
occurring in western areas of the swamp where standing water is abundant. Principal species
include cypress (Taxodium distichum), tupelo gum (Nyssa aquatica), and swamp blackgum (Nyssa
biflora). Although cypress and tupelo gum are climax species for undisturbed wet sites, blackgum
and red maple have replaced them over much of their range due to selective cutting of cypress,
drainage, and fire.
• Maple-gum forests cover sixty percent of the Great Dismal Swamp NWR and consist primarily of red
maple and blackgum (often in association with redbay, sweetbay, sweetgum, and yellow poplar).
The range of the maple-gum association has increased in the swamp over the past 30 to 40 years,
and it is the only refuge habitat type that is continuing to expand. Red maple reproduction may be
almost completely suppressed where deer populations flourish.
Pond Pine Woodlands and Pocosins
• Pond pine occurs on soils of high organic matter content in the swamp interior. Historically, this
community type was maintained by fire, limiting hardwood composition. Pond pine woodland still
dominates many acres in the southern portion of the refuge, however fi re suppression has allowed
an increase in the hardwood component.
• Pocosin vegetation is commonly found in the understory of pond pine woodlands. A pocosin is a
specific successional stage of many coastal palustrine wetlands, dominated by broadleaved
evergreen shrub vegetation less than 20 feet tall. Pocosins occur in areas of poorly developed
internal drainage on organic soils. Much of this community is being overtopped by maple and pine.
• The pine/pocosin habitat is prime foraging for the black bears and some of the highest densities of
female bear ranges include this habitat type.
• Biologists involved with recovery of red-cockaded woodpeckers endangered species have indicated
that the pine/pocosin forests within the refuge are potentially valuable habitat for the reintroduction of the Red-cockaded Woodpecker.
Marsh Habitat
• Remnant Marsh (35 acres): Originally over 300 acres, this open marsh area has become overgrown
by red maple. The entire unit has been burned several times and is now maintained as a seasonally
flooded open marsh. The Remnant Marsh once covered over 250 acres and provided brood and
feeding habitat for waterfowl and wading birds.
• Fringe Marsh (75 acres): The natural southward waterflow from the refuge is impounded by U.S.
Highway 158 creating this narrow open marsh. A portion of the unit was cleared using heavy
equipment in 1987. Additional acreage was converted from maple forest to marsh as the result of
an escaped fire.
• Railroad and West Marsh (5 acres): This area of maple/gum forest was cleared in 1985 using heavy
equipment and has now been burned four times to maintain an open marsh habitat. Since 1996
beavers have impounded the area and are currently doing an excellent job of woody plant control.
Means-Ends Exercise: Deschutes National Forest, Marsh Project Example
MEANS-ENDS DIAGRAM DEVELOPMENT SMALL GROUP EXERCISE B
Created by: Christy Ihlo, Nicholas Institute for Environmental Policy Solutions at Duke University
Description of Exercise
The goal of this exercise is to experiment with developing means-ends diagrams. Via email, you received
background information for each of those examples and each table is assigned one of the examples
(noted on the index card in the center of the table). One copy of background materials has been
provided per table.
Use the background materials to diagram ecological changes driven by the given management option
and their connections to ecosystem services.
Getting Started: An Example Generic Means-Ends Diagram
For each example, the management alternative is given. Some ecosystem services are noted in the
background information. However, your diagram should not be limited to the services given. Also,
remember that ecological changes includes structures (e.g., forest or wetland structure, but also things
like the soundscape or viewscape of an area), processes (e.g. evapotranspiration, filtration, erosion), and
conditions (e.g., air or water quality).
Means-Ends Exercise: Deschutes National Forest, Marsh Project Example
Example: The Marsh Project at Deschutes National Forest
The Deschutes National Forest (DNF) in Oregon has been exploring applications of ecosystem services
since 2009. The Forest partnered with the Forest Service’s Pacific Southwest Research Station to
develop an ecosystem services framework for forest management and planning. To test this framework,
DNF chose the Marsh Project as a pilot site. The Marsh Project encompasses a 30,000 acre watershed in
Deschutes National Forest. The focal point of this project is an area known as the Big Marsh, which is
one of the largest high elevation wetland/marsh ecosystems in the continental U.S. This site was chosen
for two reasons: the Marsh offers a wide array of services that are important to very diverse groups of
stakeholders, and it presented a good opportunity to test their ability to engage stakeholders early in
the planning process. By engaging the public at the start of the planning process, the Forest Service
hoped to accomplish three goals: increase public interest and support in the Service’s planning efforts,
increase the number of partnerships to implement projects, and increase the efficiency of the NEPA
process by incorporating values at the start of plan development.
This project began with a public scoping process to identify the benefits provided by the Marsh that
people valued. At the end of the scoping process, managers had identified four priority benefits, or
desired outcomes, that were important to stakeholders:
•
•
•
•
•
Sustain wildlife and botanical biodiversity (including Matsutake mushrooms, which are
harvested both commercially and non-commercially)
Maintain cultural values and sense of remoteness, scenic views, and self-discovery
Provide dispersed recreation opportunities (in quantity, and more importantly, quality) – both
camping as well as winter and summer trail use
Maintain functional hydrology for supporting wildlife and biodiversity both within the planning
area as well as the contribution to downstream systems
Provide for forest products (firewood, post and pole, timber) and mushroom harvesting
opportunities
Managers then determined a number of actions that could produce these desired outcomes, one of
which is reducing upland fuels and tree density through prescribed burning.
Task: Create a means-ends diagram using the management action of prescribed burning to map the
connections between fuel treatments and the provision of ecosystem services.
Getting Started
• The list of “priority benefits” can be translated into more commonly recognized ecosystem
services to use in a means-ends diagram. For example, “maintain functional hydrology for
supporting wildlife and biodiversity both within the planning area as well as the contribution to
downstream systems” is relevant to the ecosystem services of canoeing/kayaking, recreational
fishing, biodiversity existence value, and the maintenance of consistent water yield for
downstream communities. Generate a list of ecosystem services from the list of priority benefits
and write them on the far right side of the paper. (The section “Project Purpose and Need” on
page 5 of the provided document “An Ecosystem Services Approach to Management of a
Complex Landscape: The Marsh Project” may be helpful. It is also available online at
https://nespguidebook.com/cms/wp-content/uploads/2014/11/FRMES-CE-7-FULL-PDF.pdf)
Means-Ends Exercise: Deschutes National Forest, Marsh Project Example
•
•
•
•
•
•
(Note: Wildfires in the Marsh do not affect nearby communities as the location of the Marsh is
very remote.)
Write the management action on the far left side of the paper.
Consider the first service in the list. How could prescribed burning affect the provision of this
service? What ecological changes would occur because of that alternative? Think about different
ecosystem structures, such as forest or soundscape; processes, like fire behavior; and conditions,
such as air or water quality. (If the connection between the service and prescribed burning is not
apparent, start with another service.)
What indicators could be used to measure those ecological changes?
What additional services do those ecological changes affect? (It may be helpful to think about how
specific indicators may relate to ecosystem services.) Could those services be affected by other
ecological changes?
Continue this iterative process of identifying ecological changes/indicators and services until the
group feels that most of the interactions have been captured. Additional background information is
summarized on the next couple of pages and will be helpful.
Some important things to remember:
o The process of creating the diagram may identify additional services that were not on the
original list.
o Not all services originally listed may be affected by prescribed burning.
o Indices describing the quality of ecological structures (e.g., soundscape or viewscape) may be
helpful in relating those types of ecological changes to ecosystem services.
Links to additional background information:
• The draft Environmental Impact Statement (EIS) for the Marsh project can be found at:
http://a123.g.akamai.net/7/123/11558/abc123/forestservic.download.akamai.com/11558/www/ne
pa/91281_FSPLT3_2336922.pdf.
Additional Background (summarized from the EIS)
•
(Except from the Scoping letter for this project)
The Forest Service proposes approximately 1,000 acres of thinning and 900 acres of prescribed
underburning. The total footprint of treatments would be 1,750 acres, as some thinning and
burning units overlap. These treatments would be strategically placed to incorporate previous
treatments and minimize impacts to ecosystem services (i.e. sense of remoteness, provisioning of
Matsutake mushrooms, etc.) while providing effective options for future fire suppression. These
treatments would provide defensible areas for fire suppression in the event of a wildfire. Additional
benefits include reduced risk of some tree insects and diseases, as well as benefits to some wildlife
species. Thinning would primarily occur in lodgepole pine and mixed conifer areas. Underburning
would occur primarily in stands dominated by Ponderosa Pine. Proposed treatment areas bisect the
Marsh planning area between areas of past timber harvest and private land in the north and
relatively untreated areas to the south which includes the majority of the Oregon Cascades
Recreation Area in the marsh project as well as late seral reserves. Remaining treatments are
located to protect dense mixed conifer areas that provide suitable spotted owl habitat as well as
within the limited areas of dry ponderosa pine. Thinning would be accomplished using variable
density thinning techniques using both commercial harvest and non-commercial treatments, with
Means-Ends Exercise: Deschutes National Forest, Marsh Project Example
•
•
•
•
•
•
•
the potential for follow-up firewood opportunities for the public. This acreage represents less than
6% of the 30,000 total acres within the project area. In scoping and values gathering for this project,
the Marsh project area was recognized for both its front-country motorized recreation (OHV,
snowmobile, dispersed car camping, scenic driving) as well as backcountry non-motorized recreation
(hiking, fishing, hunting, biking, canoeing and kayaking). Cutting across both types of activities, there
was recognition of the sense of remoteness one gets while visiting the area. Public interest is in
enhancing the recreation features currently in place (trails, campsites, fishing and hunting
opportunities etc.), but not increasing access and thus increasing visitor use.
Impacts from vegetation management activities are expected to be short-term and localized in
nature. None of these foreseen impacts would degrade the visitor experience over time and in
many cases should enhance the visitor experience through helping the forest become more resilient
to fire and/or beetle outbreak. Additionally, many of the planned treatments would open up scenic
views and improve the on the ground views; providing a pre-grazing landscape. Views of the marsh
would be enhanced as the project progresses over time, thus providing a positive effect on all
associated recreation activities.
Public comments gathered through external (public) and internal (USFS Agency) scoping, field trips
and focused meetings highlighted the importance of ecosystem services such as the existing value
of wildlife species, hunting opportunities, wildlife viewing, and vegetative biodiversity.
Potential effects of burning on the Northern Spotted Owl: In the short-term, treatments would
reduce understory trees and brush component within a unit, which could lower potential prey
habitat. Post implementation, the stands would maintain the multi-story canopy, with the reduction
in trees with six inch dbh and under. NRF (nesting, roosting, foraging) stands would have a more
open understory which would provide for increased flight maneuverability and access to prey while
reducing stand density and fuel loading. Post implementation, treatments would stimulate tree and
vegetation growth providing habitat for prey species. The gains from project implementation could
produce higher quality, longer lasting NRF in the long-term.
Potential effects of burning on the Pacific Fisher: Prescribed fire is generally used in ponderosa pine
plant associations to remove small diameter fuels and needle cast with minimal large tree loss.
Therefore, this action by would likely have minimal impact on fisher habitat because these stands
may not have the canopy or minimum tree diameter for fisher denning habitat. Fuel treatments take
place in potential denning habitat are not expected to make it unsuitable for denning as design
features are in place to protect large snags and large down wood.
Potential effects of burning on the White-headed Woodpecker: All treatments would improve
existing nesting habitat by decreasing densities of trees in the overstory and understory. Treatments
outside of nesting habitat would have the potential to create additional nesting habitat.
Potential effects of burning on the Northern Goshawk: In the short-term, fuel management
activities could reduce the amount of available habitat for prey species. Reducing prey could
potentially reduce areas utilized by goshawk for foraging as well as minimizing the availability of
prey within nesting areas. Effects from treatments would be short in duration (<10 years) and would
provide a high diversity of prey habitat (grasses, forb and shrubs), resulting in ample areas for
hunting within and outside nesting habitat in the long-term.
Potential effects of burning on the Great Gray Owl: While nesting capability may be reduced, active
forest management would reduce stem densities and improve great gray owl foraging opportunities
because visibility and access to the ground for prey would be increased. Underburning would open
the understory in stands allowing more maneuverability and foraging for great gray owls.
Underburning operations are proposed to reduce needle cast and small diameter down wood less
Means-Ends Exercise: Deschutes National Forest, Marsh Project Example
•
•
than three inches in diameter. This down wood is potential prey habitat, but down wood above 3 in.
dbh would be kept providing ample prey habitat.
Potential effects of burning on Big Game: Immediately after underburning, there would be a
reduction in forage and cover due to fire consumption. Prescribed burning would result in a shortterm loss of forage and cover currently provided by dense patches of bitter brush, ceanothus, and
manzanita on the upper slopes of the project area. Hiding cover would be restricted to treatment
unit retention areas, 15-20 percent of the unit, and untreated stands in the project area. Postimplementation, underburn treatments would increase and stimulate vegetation growth, e.g. shrub,
grass and forb, thus increasing big game forage and cover.
Potential effects of burning on the Matsutake Mushroom: Underground fungal communities or
fungi habitat can be altered by forest management activities that intensively or extensively remove
or consume the woody substrate, forest floor litter, or shrub hosts with which the species is
associated.