Identifying Significant Ecological Hubs
in Watauga County, North Carolina
David Ponder
Geographic Information Systems
for Environmental and Social Science
Appalachian State University
December 2005
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Introduction
North Carolina was the ninth fastest growing state between 1990 and 2000, with a net increase of
more than 1.4 million residents (CensusScope). While most of North Carolina’s population
growth occurred in urban and urban-adjacent areas significant growth also occurred in highamenity areas such as the High Country (NC Rural Center). During the same period, Watauga
County experienced a 15.5% increase in population while notably Boone, the county’s largest
municipality, experienced only a 4% increase in population, suggesting much of this growth
occurred in unincorporated parts of the county (High Country Council of Governments).
Furthermore, the rate of land consumption for the county, the conversion of undeveloped to
developed lands, between 1986 and 1999 was nearly 52% while the consumption rate in
unincorporated portions of the county was 66% (MountainKeepers).
These recent trends have many residents concerned that development pressures will result in
undesirable changes to the character of the landscape and deterioration in the quality of life.
Furthermore, the fragmentation of landscapes due to rapid development may result in threats to
the integrity of ‘ecosystem services,’ those benefits people derive from healthy ecosystem
functioning such as the procurement of clean drinking water (Daily). Given the value of these
services, local communities across the country are seeking to protect the integrity of natural
landscapes, through both voluntary and mandatory conservation techniques.
Both public agencies and private organizations play an active role in land conservation in
Watauga County. Public agencies participate through the acquisition and ownership of property,
the sponsorship of temporary binding agreements, and by providing funding and technical
support. Private land trusts and conservancies also play an important role through the acquisition
of private property, the purchase or donation of conservation easements, partnering with
developers to mitigate impacts, and collaborating with government agencies. All told at least
four federal agencies, six state agencies, two local government agencies, two private land trusts
working exclusively in the region, three regional or national land trusts, as well as, a number of
other conservation organizations play a role in land conservation efforts in Watauga County
While, these groups and agencies work towards common ends and opportunistically collaborate,
they tend to pursue their objectives in isolation (Trew and Coffey 2005).
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The lack of a shared comprehensive strategy among private organizations and public agencies
stands in contrast to the trend among land preservation advocates toward ‘smart’ conservation
planning that is “proactive not reactive; systematic not haphazard; holistic not piecemeal;
multifunctional not single purpose; multi-jurisdictional not single jurisdictional; and multiple
scale not single scale” (Benedict, and McMahon p14). Such comprehensive approaches are
intended to maximize protection of the most vulnerable and valuable landscapes and the
‘ecosystem services,’ they support.
The purpose of this project therefore is to construct a Geographic Information System (GIS)
model that begins to identify an interconnected network of open lands that conserves significant
ecosystem values and function which can serve as a strategic guide toward future conservation
planning in Watauga County, North Carolina.
Rationale
While ad hoc approaches to conservation can yield protection for some sensitive lands, absent a
guiding framework, such efforts may result in a patchwork protected lands that fail to sustain
critical ecosystem functions, due to size and relative isolation. Increasingly communities are
moving away from piecemeal approaches and towards “strategic and comprehensive open space
protection” within a framework of planning for ‘green infrastructure’ (Hopper 8). Green
infrastructure is an “interconnected network of green space that conserves natural ecosystem
values and functions and provides associated benefits to human populations” (Benedict and
McMahon p12).
The conservation planning principle of maintaining ecosystem services through the designation
and management of a linked network of areas of particular ecological significance is rooted in
conservation biology scholarship and in particular the notion of ‘conservation area networks’
(CANs). CANs (see Figure 1) are networks of core areas, or hubs, which have been prioritized
for protection based on biodiversity value surrounded by buffer areas that allow for restoration
and sustainable resource use. These core zones in turn are connected by natural corridors to
allow for flows between the zones (Tukel 67).
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Figure 1: Conservation Area Network
Almost all methods used in conservation planning assume that data are recorded in a GIS model.
GIS facilitates the delineation of these networks through its ability to layer multiple features.
When these layers are superimposed upon one another patterns in the landscape begin to emerge.
These patterns in turn can be used to identify significant ecological hubs.
Methodology
Based on these principles, between 1998 and 2001 the University of Florida’s GeoPlan Center
conducted a region wide GIS “landscape analysis of ecological significance and the
identification of critical landscape linkages” (SEF, i). While the resulting Southeastern
Ecological Framework (SEF) is most appropriately used to guide conservation decisions at a
regional scale, the final project report includes a case study on how the framework methodology
might be applied at a local scale. Given my limited experience with ArcGIS, the project
methodology relies heavily on the methods advanced in the SEF report. Indeed, I sought to
follow the work as closely as possible, supplementing with additional research and trial and
error.
The SEF report outlines a four stage process for identifying a local scale ecological network: 1)
determining the model parameters, 2) identifying ecological hubs, 3) identifying links between
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hubs, and 4) combining hubs and linkages. In turn, each of these stages consists of a series of
sub-process (SEF 101). The analysis presented in this paper completes the first two of these
stages (Figure 2).
Figure 2: Outline of SEF Methodology
Determine Model Parameters
 Define goals and
objectives
 Asses, collect, process
data
Identify Ecological Hubs
 Identify Significant
Ecological Areas
 Exclude unsuitable land
uses
 Optimization
 Identify Hubs

Identify Landscape Linkages
Ecological Framework
Stage One: Determining model parameters
The first step in creating the local ecological network was to determine the conservation goals
and objectives. The second step was to collect and asses the data that would serve as a proxy for
goals and objectives. Based on the recommendation in the SEF report, the availability of suitable
proxies, consideration of local newspaper accounts, as well as, review of local watershed
planning documents this analysis established the following parameters:
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Goal 1: Protection of Water Resources:
Objective 1.1 Protection of drinking water resources
Drinking water supplies, especially those reliant on surface resources, are under increasing
pressure as a direct result of the recent rapid development experienced in the county (Nicholson).
Any deterioration to existing supplies from contamination or sedimentation would only serve to
increase this scarcity. Therefore protection of water supply watersheds, those drainage basins
above water supply intakes, was included in the GIS model. The location of water supply
watersheds in Watauga County was acquired by clipping a statewide shapefile produced by the
N. C. Center for Geographic Information and Analysis (NCGIA) and the The North Carolina
Department of Environment and Natural Resources (NCDENR), Division of Water Quality
(NCDWQ).
Objective 1.2 Protection of High Quality and Outstanding Resource Waters
NCDWQ has designated certain water bodies as High Quality or Outstanding Resource Waters
(HQW or ORW) based on their exceptional water quality. These resources are among the few
pristine in the state and deserve special consideration as a result of the exception ecological and
recreational significance. HQW and ORW streams in Watauga County include the headwaters
of four major river networks and wild trout waters. NCGIA has created a GIS data set
representing the location of waters surrounding regions of stream or bodies of water identified as
HQW or ORW by NCDWQ. For this analysis these zones were clipped to Watauga County.
Goal 2: Protection of Ecological Processes:
Objective 2.1 Protection of wetlands
Wetlands are areas typically inundated or saturated with water for periods long enough to
support vegetation adapted to these types of conditions to thrive. Wetlands, such as bogs and
marshes, support healthy ecosystem functioning through the filtration of sediment and other
contaminants, the recharge of water supplies, the mitigation of flood waters, and the provisioning
of habitat (EPA). The wetlands data used in the GIS model was acquired from the U.S. Fish and
Wildlife Services National Wetlands Inventory and buffered by 300 feet per the SEF
methodology.
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Goal 3: Protection of Biodiversity:
Objective 3.1 Protection of Significant Natural Heritage Areas
The NC Natural Heritage Program (NCNHP), a division of DENR, identifies Significant Natural
Heritage Areas (SNHAs) as the most important areas for natural diversity of the state.
A SNHA may derive its significance from the presence of rare species, rare or high quality
natural communities, or other important ecological features. Biological inventories have
identified 136 species of concern known to occur in Watauga County (NCNHP). The boundaries
of SNHAs in Watauga County were derived from NCGIA shapefiles.
Objective 3.2 Protection of existing conservation lands and areas immediately surrounding them
Local land trusts as well as federal and state agencies have already worked to protect x acres of
sensitive lands in Watauga County. Since these areas already enjoy protection from
development they tend to have high densities of biota, however in order to maintain the integrity
of these systems from negative edge effects the SEF methodology recommends buffering these
lands by 300 meters. No single data source existed for all conservation lands in Watauga County
so one had to be created. This was accomplished by merging several shapefiles and adding
additional parcels known to be under conservation easements. The result is a shapefile that
includes federally and state managed lands (Blue Ridge Parkway and associated parks, , Elk
Knob State Natural Area, Appalachian State University’s Tater Hill Bog Research Area, state
managed gamelands, etc.) as well as private lands managed for conservation (private parcels
receiving conservation easement tax credits, Grandfather Mountain, etc.).
Objective 3.3 Protection of roadless areas
Roads are a leading cause of habitat fragmentation and loss because in addition to creating
physical barriers between habitats they bring with them negative edge effects such as noise,
contaminated runoff, and the proliferation of invasive species. Therefore roadless areas are
important for biodiversity because they offer unfragmented patches of habitat. To determine
roadless areas all primary, secondary, and local road centerlines from NCGIA were merged,
buffered by 100 feet, and clipped to the study area. Resulting polygons greater than 1000 acres
were designated roadless.
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Objective 3.4 Protection of areas important for endangered aquatic species
The N.C. Wildlife Resource Commission in conjunction with NCGIA has mapped the extent of
extent of endangered or threatened aquatic species populations and the tributaries and headwaters
of their habitats. These waterways were then buffered by 100 feet and clipped to Watauga
County.
Stage 2: Identifying Ecological Hubs
Identify Significant Ecological Areas
After data layers were created to represent all of the conservation goals and objectives they were
merged into a single shapefile and polygon boundaries were dissolved, creating a single polygon
called Significant Ecological Areas or SEA (Figure 3).
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Exclusion of Unsuitable Land Uses
After the identification of SEAs those portions overlapping incompatible land use were removed.
The determination of exclusion areas again closely follows the methodology set out in the SEF
report and included:
Primary road exclusion
U.S. 421, U.S. 321, U.S. 221, and Highways 194, 105, 88, and 188, were selected from the
NCGIA primary road data ad buffered by one quarter mile. These highways are the backbone of
the transportation infrastructure in Watauga County with average daily traffic counts typically
exceeding 10,000 vehicles. The heavy traffic volume and associated negative edge effects are
the reason for their exclusion.
Areas with high road densities
Areas with road densities greater than or equal to three miles per square mile were excluded
because they exceed road density thresholds for sensitive species. A line density analysis was
preformed on a combined (primary, secondary, and local) road file. Those areas that exceed the
standard were reclassified and converted into a shapefile for exclusion.
High intensity land use
High intensity land uses were extracted from a land cover file obtained from Highland Mapping
of Banner Elk, NC and prepared for the MountainKeepers Forces of Change Report. The land
use raster was based on satellite imagery from 1999. Those areas designated as ‘developed’ or
‘cultivated’ were reclassified and converted into a shapefile for exclusion.
Areas in close proximity to urban land uses
Per the SEF methodology, all areas within "neighborhoods" with extensive urban land use in 90meter 3X3, 9X9, and 27X27 windows that exceed greater than or equal to 50% urban land use
were identified and converted into shapefiles for exclusion. This addition to the exclusion layer
is intended to mitigate the influence of clusters intensive land use. Additionally all clusters of
intensive land use greater than 100 acres were buffered by 270 meters.
The exclusion values were merged into a single shapefile and overlaid on the SEA to produce a
new layer, Significant Ecological Area after Exclusion, or SEAX (Figure 4).
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Identification and Optimization of Ecological Hubs
After SEAX are identified they were ‘optimized’ by filling internal gaps and smoothing outside
edges where compatible land uses occurred. This was accomplished by reclassifying suitable
land use data (forest and grassland cover) and converting it to a shapefile then a select by
location. Those areas of suitable land use that intersected with gaps were then merged into the
SEAX shapefile. Edge smoothing was accomplished by applying a 10 meter buffer to the new
SEAX.
All contiguous SEAX polygons greater than 1000 acres were then selected and designated
Ecological Hubs. A final optimization and is preformed to add back in all currently protected
conservation lands and all resulting polygons greater than 1000 acres constitute the final set of
ecological hubs (Figure 5).
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Discussion
Nine ecological hubs emerged from the analysis. Below is a description of each hub and its
primary SEAs components. Names were given to each hub in order to better conceptualize the
location of each.
Hub 1: Grandfather Mountain
Hub one consist of areas along the Blue Ridge Parkway and adjacent to Grandfather Mountain.
It contains the tip of Grandfather Mountain which extends into Watauga County, as well as,
Julian Price and Moses Cone Memorial Parks. The area also contains the headwaters for
Winkler’s Creek upstream from the Town of Boone’s drinking water intake point.
Hub 2: Watauga Lowlands
This hub contains the lower elevation areas in the eastern part of the county. These lands are of
primary concern because of the large tracts of undeveloped roadless areas. The also contain the
headwaters for the Yadkin and Catawba River.
Hub 3 and 5: Valle Crucis
This hub contains the historic Valle Crucis community. The hub emerges from the analysis
because of the aggressive acquisition of conservation easements in the valley including the 430
acres easement for the Valle Crucis Conference Center. The area also include the Valle
Mountain SNHA.
Hubs 4 and 7: New River
These hubs are located along the county’s north east boundary with Avery County. These hubs
are included because of their relative location to the New River and large tracts of undeveloped
roadless areas.
Hubs 6 and 9: Amphibolite Mountains
The mountain peaks in this hub are part of the and contain headwaters for the New River. The
presence of amphibolite soils makes the region one of the most important "hotspots" for natural
diversity in the entire Southeast. Among the landmarks of the New River Headwaters are Bluff
Mountain, Tater Hill Lake Bog, Rich Mountain, Elk Knob and Long Hope Valley.
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Hub 8: Cove Creek
This hub includes the Cove Creek drainage and areas adjacent to Snake Mountain along the
North Carolina and Tennessee boarder. Snake Mountain is the highest peak in Watauga County
and contains the headwaters of the North Fork of the New River.
Limitations of analysis
These results also come with some caveats and the acknowledgement of a flaw in methods. First
the caveats; the network is the result of one person’s work and imagination. While I attempted to
incorporate what I though of as community concerns, no other members of the community
participated or contributed to the work. This is significant because the results may have been
different if other ‘knowledges’ had been represented. A participatory approach may have
revealed more specific knowledge about the place or taken the analysis in an entirely different
direction. Members of the Audubon Society might know the location of wetlands that do not
appear in satellite imagery. Others might have sought the inclusion non-ecosystem ‘values,’ like
the social and cultural functions of agricultural landscapes.
Secondly, while the intent of my mapping effort was to produce a more ‘objective’ framework
for where land conservation efforts might be directed, it is still a generalization and as such does
not reveal the nuances of a place. The methods I relied upon to produce the ‘ecological hubs’
have no reality check built in, no on the ground confirmation about the claims made about the
place. This is a notorious concern for map making that relies on remote sensing and satellite
imagery because computers models do not always accurately reflect actual land use and because
the resolution of these images obscures multiple land uses in a given cell.
Finally other data concerns also prevented a complete analysis. For example, the land use and
land cover data was from 1999 at a resolution of 82 square meters and my limited GIS skills
precluded the inclusion of more current imagery. My novice abilities precluded the inclusion of
other data sets as well; I would have liked to have included a layer delineating first and second
order headwater streams. My own limits were not the only thing prevent other data layers from
being included; data availability was also an issue. I was unable for example to locate data about
non municipal drinking water supply, such as groundwater recharge areas.
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In hindsight I made at least mistake in my methods. Because my original interests revolved
around the affects of growth in Watauga I failed to consider the edge effects of adjacent areas.
This is most readily seen in the clustering of final ecological hubs along the county’s boundaries.
My failure to consider the land use and ecological systems functioning in adjacent areas likely
skewed the results in favor of larger ecological hubs.
Conclusions
Because of the limits inherent with this analysis it is my opinion that the determination of these
particular ecological hubs are not sufficient to serve as a strategic guide toward future
conservation planning in Watauga County, North Carolina the issues. This is not to say that the
general approach followed is itself flawed. Indeed, I believe that given enough time some of
these limits might have been overcome. Potential application of a more robust analysis might
suggest where to set priorities for future open space and conservation planning by local agencies
or land trusts.
Finally, I believe that GIS ability to reveal the complex and interconnected character of
landscape features can help reinvigorate people’s ‘sense of place.’ When we have a better
understanding of where we live then we are more likely to make personal choices and policy
decisions that support ecosystem functions.
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Works Cited
Benedict, Mark and Edward McMahon. "Green Infrastructure: Smart Conservation for the 21st
Century." Renewable Resources Journal. Vol. 20, No. 3: 12-17, 2002.
Daily, Gretchen, et al. “Ecosystem services: Benefits Supplied to Human Societies by Natural
Ecosystems.” Issues in Ecology, Number 2, 1-16, 1997.
Hopper, Kim, ed. Local Greenprinting for Growth: Using Land Conservation to Guide Growth
and Preserve the Character of Our Communities, Vol. 1. Trust for Public Land, 2002.
Nicholson, Scott. “County receives water estimate,” Watauga Democrat, Boone, NC, November
21, 2005. Accessed December 3, 2005 at
http://www.wataugademocrat.com/2005/1121web/countyreceiveswaterestimate.php3
Trew, Phil and Kelly Coffey. “Open Space Protection & Priorities in the High Country Region.”
Boone, NC: High Country Council of Governments, 2005.
Tokel, George. “Wild at the Heart: Planning from the Wild Center Out,” in Boundries of Home:
Mapping for Local Empowerment, Doug Aberley, ed. New Society Publishers:
Philadelphia, PA, 1993.
“Functions and Value of Wetland,” EPA Office of Wetlands, Washington DC, September 2001.
Accessed December 3, 2005 at http://www.epa.gov/owow/wetlands/pdf/fun_val.pdf
“Final Report: Southeast Ecological Framework.” University of Florida GeoPlan Center,
Gainsville, Fl., May 2002. Accessed December 3, 2005 at
http://www.geoplan.ufl.edu/epa/download/sef_report.pdf
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