2010 SOUTHEASTERN NATURALIST 9(3):573–586
Landscape Scale Correlates of Fox Squirrel Presence on
Golf Courses in Coastal South Carolina
Kristin Meehan1,2 and Patrick G.R. Jodice3,*
Abstract - The coastal plain of the southeastern United States has experienced rapid
and intense urbanization that has substantially changed the area’s landscape. Much of
this landscape change has been associated with the development of golf courses and
associated communities, and cumulatively, these landscape units occupy thousands
of hectares in the region. The opportunity for these golf courses to support native
wildlife requires examination as these habitats are becoming more common and often
represent some of the largest tracts of remaining open space within an area. Although
declining throughout the southeastern US, Sciurus niger (Fox Squirrel) populations
are still found on golf courses in this region. We investigated the relationship
between Fox Squirrel presence and landscape characteristics on 98 golf courses in
coastal South Carolina. Visual and telephone surveys indicated Fox Squirrels were
present on 68 of the courses surveyed. The best predictor of Fox Squirrel presence
on a course was the presence of a Fox Squirrel population on the nearest neighboring
course. The probability of Fox Squirrels being present on a course if they were
also present on the nearest neighboring course was 87.3%. Course age was the best
predictor of Fox Squirrel presence on golf courses without a Fox Squirrel population
on their nearest neighboring course. Our results suggest that regional Fox Squirrel
populations may be stabilized by multi-patch population dynamics.
Introduction
The role of golf courses in wildlife conservation has become increasingly
important in areas where development is prevalent, where native habitats are
declining and becoming fragmented, and where golf courses often represent
some of the largest tracts of remaining open space (Angold et al. 2006, Yasuda
and Koike 2006, Zipperer et al. 2000). For example, the coastal plain
of the southeastern United States was historically characterized by a mix
of forest, agricultural land, and rural communities. Since the mid-1960s,
rapid and intense urbanization has substantially changed the landscape of
the Southeast (Allen and Lu 2003). A common change to this landscape has
been the development of golf courses and associated communities, which
now occupy thousands of hectares in the region (Jones et al. 2005). Many of
these golf courses were created from large parcels of undeveloped or rural
land, and when originally constructed, were surrounded by coastal forest.
As such, the landscape was often characterized by isolated golf courses
1Department of Forestry and Natural Resources and South Carolina Cooperative
Fish and Wildlife Research Unit, Clemson University, Clemson, SC 29634. 2Current
address - Landmælingar Íslands, Stillholti 16-18, 300 Akranes, Iceland. 3US Geological
Survey, South Carolina Cooperative Fish and Wildlife Research Unit, Clemson
University, Clemson, SC 29634. *Corresponding author - pjodice@clemson.edu.
574 Southeastern Naturalist Vol. 9, No. 3
surrounded by a matrix of undeveloped or lightly developed lands. However,
as urban areas have expanded and as development has increased adjacent to
golf courses, many golf courses have instead become surrounded by higherintensity
development. In these instances, golf courses frequently become
the largest parcels of open space remaining in a matrix of development and
may represent important wildlife habitat.
Currently, the maintenance or preservation of specific types of habitat for
wildlife on golf courses occurs infrequently by design, and any planning that
does occur appears to happen at a within-course scale. The potential for golf
courses to act as wildlife habitat could be improved if species requirements
were considered prior to development (Love 1999, Terman 1997) and if
landscape-scale factors (e.g., multiple courses, adjacent undeveloped lands,
corridors) were considered, the latter being especially critical for species that
require habitat patches that are larger than those offered by most courses.
Such an approach, however, requires species-specific studies that provide
an understanding of the factors which affect species presence specifically
in a setting comprised of urban golf courses (Hodgkison et al. 2007, Mason
2006). Often these data are lacking, or in cases where data do exist, much
of it pertains to requirements of avian species (e.g., Cristol and Rodewald
2005) or to species that do not require extensive landscapes, such as small
mammals or herpetofauna (Barthelmess 2004, Montieth and Paton 2006).
Habitat-use data for meso- or large mammals that move among patches in an
urban landscape (e.g., Adkins and Stott 1998, Ditgen et al. 2007) are rare due
to the difficulty of observing these species and the complexity of examining
landscape-level attributes.
Our goal was to investigate the occurrence of Sciurus niger (L.) (Fox
Squirrel) on golf courses along the coast of South Carolina. This species
is declining throughout much of the southeastern US (Loeb and Moncrief
1993), but is often observed on golf courses in the region. Use of golf courses
by Fox Squirrels may be due in part to similarities in habitat structure
between this species’ commonly used native habitat (mature pinelands with
open-understory and mast producing hardwoods) and that provided by many
of the golf courses in the region, and to abundant food resources that often
occur on courses (Jodice and Humphrey 1992, Lee et al. 2008). Population
viability for this species may be affected, however, not only by within-course
habitat attributes but also by the matrix and landscape-scale characteristics
surrounding golf courses (Ditgen 1999, Jodice and Humphrey 1993). For
example, Fox Squirrels inhabiting golf courses move between courses either
as part of their naturally high rate of natal dispersal or simply to access other
individuals or areas for breeding or feeding (Ditgen 1999). Thus, both within-
course habitat structure and landscape characteristics require attention for
the conservation of this species in these golf course settings. Although neither
of these relationships have been examined extensively, the former has
received more attention than the latter in the southeastern US (e.g., Ditgen
et al. 2007; Jodice and Humphrey 1992, 1993; Lee et al. 2008). Therefore,
2010 K. Meehan and P.G.R. Jodice 575
our objective was to use a model-selection approach to assess the relationship
between Fox Squirrel presence on golf courses along the South Carolina
coast and landscape-scale features. Determining the importance of habitat
features for Fox Squirrel presence on golf courses at the landscape-scale will
provide insight into the potential long-term viability of this declining species
in the southeastern coastal plain.
Methods
Study species and study area
The southeastern Fox Squirrel is listed as a species of concern in South
Carolina. Fox Squirrel populations appear to be declining throughout much of
the southeastern US due in large part to the loss of native Pinus palustris Mill.
(Longleaf Pine) habitat (Harrigal 1993, Loeb and Moncrief 1993, Weigl et al.
1989). Home ranges of southeastern Fox Squirrels vary by region and habitat
conditions, but often are >35 ha (Ditgen 1999, Jodice 1993, Kantola and
Humphrey 1990, Perkins and Connor 2004). Road mortality can be significant
(McCleary et al. 2008), even in areas with relatively low traffic volumes (Lee
et al. 2008), and dispersing subadult Fox Squirrels may move between habitat
patches in urban regions, traveling up to 6 km (Ditgen 1999).
Our study was conducted on 98 golf courses that were located within
the Coastal Plain and Coastal Zone ecoregions of South Carolina (Fig. 1).
Figure 1. Location of study area in coastal South Carolina, showing coastal ecoregions.
576 Southeastern Naturalist Vol. 9, No. 3
The Coastal Zone ecoregion is a subset of the Coastal Plain and is found
seaward of the state inland marine waters boundary. The courses included
in this study occurred along the entire length of the South Carolina coast,
although there was a large unstudied area in the central part of the coast
which included numerous public lands and few golf courses (Fig. 2). We
only included golf courses in the study if the landscaping was complete as
of 1999 to ensure that the landcover data, based on 1999 satellite imagery,
matched the study courses. Golf courses which substantially differed in appearance
between aerial photos and the national landcover dataset (NLCD)
were not included in the study. Furthermore, any golf courses located on sea
islands where Fox Squirrels were absent outside of golf course habitats were
not included in analyses. Golf courses were counted as one entity for data
analysis when they adjoined each other, shared the same owner, and were
managed as one unit.
Fox Squirrel surveys
The goal of the surveys was to determine presence or absence of Fox
Squirrels on southeastern golf courses. We conducted phone surveys
with staff at 98 golf courses. Typically the contact was either a course
Figure 2. Extents for which land-cover data were analyzed to determine models of
Fox Squirrel presence on 98 golf courses along the coast of South Carolina. Study
courses were not located along the central portion of the coast because that area is
relatively undeveloped, with large parcels of land in public ownership.
2010 K. Meehan and P.G.R. Jodice 577
superintendent or golf professional, as they were generally the most familiar
with landscaping and ecological issues on the course. Along with
questions about design and characteristics of golf courses, we also asked
whether or not Fox Squirrels had been observed on the golf course during
the past year. Although we requested estimates of Fox Squirrel abundance
based upon number of sightings per month, we only used presence
or absence categories for data analysis because we were not certain that
estimates from course personnel were accurate and we were not able to
conduct on-site surveys that resulted in adequate or balanced coverage
across all golf courses (see below). Because the Fox Squirrel differs substantially
from Sciurus carolinensis (L.) (Gray Squirrel) in size, coloration,
and behavior, and because we included questions in our interviews that focused
on coloration and behavior, we were confident that respondents were
correctly reporting presence of Fox Squirrels.
We also conducted on-site surveys for Fox Squirrels at 51 of the 98 golf
courses to determine the accuracy of the interviews with respect to Fox
Squirrel presence or absence and to obtain relative estimates of abundance.
These abundance estimates were not used in data analysis, but rather as a
qualitative assessment of population status on our study courses. We did not
attempt to obtain a more accurate measure of density or abundance because
we were restricted to conducting surveys from golf carts and from cart paths
by most course personnel and had limited time on each course. These restrictions
made it difficult to survey all portions of a golf course. Nonetheless, the
high visibility within golf courses allowed for a thorough search of the active
areas such as greens, fairways, tee boxes, and other managed landscapes
which appear to represent the majority of habitat used by Fox Squirrels on
golf courses in the southeastern US (Ditgen et al. 2007, Jodice and Humphrey
1992). Therefore, we are confident that presence and absence could be
determined accurately.
All surveys were conducted from golf carts driven at ca. 3.5 km/h along
cart paths. We surveyed for squirrels using a strip-transect design (50 m on
either side of the cart path). Because golf courses maintain a relatively open
understory, we are confident that we met the assumption of equal detectability
of individuals located on or near the ground throughout the strip transect.
Surveys were conducted twice on each course: once between May and
June 2005, and once between November 2005 and February 2006. Spring
and summer surveys were conducted between sunrise and 1200 h, while
fall and winter surveys were conducted between sunrise + 1 h and 1400 h.
Survey times coincided with higher incidences of foraging and traveling activity
of Fox Squirrels in the southeastern US (Jodice and Humphrey 1992)
and provided the highest probability of detection. Given that Fox Squirrels
in the southeastern US allocate substantial time to foraging and traveling
on the ground during our survey hours and that these activities often occur
along the ground (Jodice and Humphrey 1992, Koprowski 2005), we suggest
that our ability to determine presence or absence was not compromised by
578 Southeastern Naturalist Vol. 9, No. 3
limiting our surveys to the area observed from the cart (ground, lower tree
boles, lower canopy).
Remote sensing/GIS
We used aerial photos taken in 1999 (most recent complete set available),
mailing addresses from the United States Golf Association member
listings, GPS data collected during field visits, or geocoding of street
addresses using ArcGIS 9.1 (ESRI, copyright 1999–2005) to locate and
identify golf courses in the geographic information system. Because cadastral
data were not universally available, we were not able to spatially define
all golf courses by property boundaries. Instead we created a minimum
convex polygon that circumscribed the outermost fairway for each course.
This method resulted in each golf course being represented by a polygon
that included all of the actively managed areas of the course. This delineation
also matched the spatial extent of our on-site survey data, which
were collected from cart paths. On some courses, this delineation resulted
in an area that excluded associated housing developments or unmanaged
land. These excluded areas were, however, included in analyses as buffers
clipped to each course (see caption for Fig. 2 and description below for
landscape clipping at three different scales).
Land cover, tree canopy closure, and paved surface cover were extracted
from the 2001 National Land Cover Database (http://www.mrlc.
gov/mrlc2k_nlcd.asp accessed 12/12/2006), the most current land-cover
data available for the study area. The NLCD is recommended for analysis
of wildlife habitat data at the landscape scale (Cunningham 2006).
Wetland classes were combined because previous research demonstrated
that Fox Squirrels rarely use these land classes (Jodice 1993, Kantola and
Humphrey 1990, Koprowski 1994). Grassland classes also were combined
because Fox Squirrels appear too use these habitats primarily as movement
corridors (Nupp and Swihart 2000). The multiple classes for developed
land also were merged because the developed land-cover subtypes had
lower levels of accuracy compared to other classes in our study area (Homer
et al. 2004). A roads layer was created from 2000 Census Tiger/Line
data, which was converted to a raster dataset based on the average width of
each road type in the data set (American Association of State Highway and
Transportation Officials 2004).
We used Hawth’s Analysis Tools (Beyer 2004) and ArcGIS (ESRI, Redlands,
CA) to clip the land-cover and road grids to individual golf courses
at three different scales: the golf course itself, the golf course with a 1-km
buffer, and the golf course with a 5-km buffer (Fig. 2). We used Fragstats
3.3 (McGarigal et al. 2002) to calculate landscape-, patch-, and class-scale
metrics for all datasets.
Data analysis
We developed 22 logistic regression models (Table 1) to assess the relationship
between presence of Fox Squirrels on a golf course and various
2010 K. Meehan and P.G.R. Jodice 579
landscape and habitat attributes on and adjacent to the course. We considered
various aspects of the ecology of Fox Squirrels, urban ecology, and fragmentation
effects on wildlife when developing these a priori models. For
example, models included factors such as the proximity of other populations
of Fox Squirrels (models 1–8), the extent of development on or surrounding
the golf course (models 9–14), vegetation structure on and adjacent to
the golf course (models 15–17), and individual attributes of golf courses
(models 18–22). Select models included habitat and landscape characteristics
surrounding the golf course by including the area within 1 and 5 km of
the golf course polygon. We also used 19 of the 22 models to analyze data
only on golf courses (n = 35) that did not have Fox Squirrels on their nearest
neighboring golf course (Table 1).
Table 1. Logistic regression models used for analysis of Fox Squirrel presence on 98 golf
courses in coastal South Carolina.
ModelA Parameters included in model
Models that consider proximity of Fox Squirrel populations
1 Distance to edge of nearest neighboring course with Fox Squirrels; total area of courses
within 5 km with Fox Squirrels
2 Distance to edge of nearest neighboring course with Fox Squirrels; total road area within
1 km of course
3 Presence of Fox Squirrels on nearest neighboring course
4 Distance to nearest golf course with Fox Squirrels
5 Total area of all courses within 5 km with Fox Squirrels
6 Distance to edge of nearest neighboring course with Fox Squirrels; total road area within
1 km of course; Presence of Fox Squirrels on nearest neighboring course
7 Distance to edge of nearest neighboring course with Fox Squirrels; total area of courses
with Fox Squirrel populations within 5 km; presence of Fox Squirrels on the
nearest neighboring course
8 Distance to nearest golf course with Fox Squirrels
Models that consider the amount of developed area on and nearby the course
9 Total developed landcover within course
10 Total developed landcover within 1km of course
11 Developed landcover within 5 km of course
12 Total area on course with >50% impervious cover
13 Area of all road types within the course boundary
14 Area of all roads within 1km of the course
Models that consider the amount of various vegetation classes on and nearby the course
15 Area within course of coniferous, deciduous, mixed, and shrub/scrub forest; grass,
wetland, and open water
16 Area of cover within 1 km of course of coniferous, deciduous, and scrub/shrub forest;
grass, wetland, and open water
17 Area of cover within 5 km of course of coniferous, deciduous, and scrub/shrub forest;
grass, wetland, and open water
Models that consider individual course attributes
18 Total course area; patch fractal dimension
19 Simpson's diversity index
20 Gray Squirrel presence or absence
21 Latitude of course
22 Year course was built
AModels 6 and 7 were not used in instances where Fox Squirrels were absent from the nearest
neighboring course.
580 Southeastern Naturalist Vol. 9, No. 3
Once the models were created, we analyzed each using PROC LOGISTIC
(SAS/STAT system version 9.1, 1999–2005 SAS Inc., Cary, NC) and
then used a model-selection approach to rank and assess models (Burnham
and Anderson 2002). Models were ranked using AIC values corrected for
small sample size (AICc), and we used AICc weights (wi ) to define a set of
models which included the best model in 90% of samples (i.e., 90% confi-
dence set of models, sensu Burnham and Anderson [2002]). This group was
comprised of all the models which, when ranked, had a cumulative weight
of approximately 90%. When using the model-selection approach, it is common
to calculate estimates for regression coefficients (and hence odds ratios)
for each variable in the confidence set, and to do so using a weighting scheme
based on the model averages (Burnham and Anderson 2002). We applied this
strategy to results that included all courses and present the weighted odds ratios
in the results. For results that included just the subset of courses for which
there were not Fox Squirrels present on the nearest neighboring course, we
only present the odds ratios for variables from the highest ranked model because
that model weight was substantially higher than all other models.
All means and coefficient values are reported ± 1 SE unless otherwise noted.
Results
Survey and landscape summary statistics
Fox Squirrels were reported as “present” on 35 of 47 (74.5%) golf
courses contacted by telephone only and were observed on 33 of 51
(64.7%) golf courses where onsite surveys were conducted. On these latter
golf courses, the maximum number of Fox Squirrels counted was 55,
although on only 8 of these courses did we count ≥10 Fox Squirrels. Of the
51 golf courses where surveys were conducted, 36 reported via telephone
surveys that Fox Squirrels were present. Hence, there was a 91.7% agreement
in determining presence of absence or Fox Squirrels between phone
and on-the-ground surveys. The three golf courses with conflicting results
each categorized Fox Squirrels as very rare with <1 observation estimated
per month. The proportion of courses with Fox Squirrels present did not
differ between those surveyed in person and those for which presence
was determined via telephone interviews (χ²=1.1, P >0.2). Based on these
results, we therefore considered the phone surveys to be accurate for classification
of Fox Squirrels as present or absent and subsequently analyzed
data from all 98 golf courses.
The golf courses included in this study had a mean age of 24 ± 1.5
years and a mean area of 126.8 ± 7.2 ha (range 25.5 to 400.4 ha). The golf
courses included in this study were moderately forested, with 44.0 ± 1.7%
(range 9.3%–83.4%) of the total area of the course having greater than
20% canopy cover (n.b., these values refer only to the course polygon
itself and hence primarily include the fairways and interior roughs). The
mean distance from a course to the next nearest course was 1.4 ± 0.2 km.
For golf courses with Fox Squirrels, the mean distance to the nearest
2010 K. Meehan and P.G.R. Jodice 581
neighboring course that also supported Fox Squirrels was 1.9 ± 0.5 km,
while for golf courses without Fox Squirrels the mean distance to the
nearest neighboring course that supported Fox Squirrels was significantly
(t96 = 2.2, P = 0.03) greater at 2.5 ± 0.4 km.
Modeling Fox Squirrel presence
Two models best predicted the presence of Fox Squirrels on golf courses
along the South Carolina coast, and the 90% confidence set of models included
only these two models (Table 2). The difference in the AIC values
between the first and second-ranked models, however, was only 1.04, and
hence these two models are not easily differentiated. Nonetheless, both the
first- and second-ranked models included a term for the presence or absence
of a Fox Squirrel population on the nearest neighboring course (NNFP).
The odds ratio for NNFP indicated there was an 87.3% probability that Fox
Squirrels would be present on a course if they also were present on the nearest
neighbor course, but only a 31.4% probability that Fox Squirrels would
be present on a course if they were not present on the nearest neighboring
course. The second-ranked model also included variables that reflected proximity
to nearby populations of Fox Squirrels (Table 2).
We also assessed the relationship between Fox Squirrel presence and
landscape and habitat variables just on courses where Fox Squirrels were
not present on the nearest neighboring golf course (n = 35). We did this to
determine which factors may be important to Fox Squirrel presence in the
absence of a nearest neighboring course population. Fox Squirrel presence
on this subset of golf courses was best predicted by the age of the golf course
(Model 22; Table 3). This model had a 57% relative likelihood of being the
best model for predicting Fox Squirrel presence on this subset of golf courses
and was approximately 6.3 times more likely to be the best model than the
next-highest ranked model. The odds ratio from this model indicated that the
probability of a course having Fox Squirrels improved by 1.74% with each
1-year increase in course age. Coefficient estimates for other parameters in
the 90% confidence set of models were very close to zero; since these parameters
did not contribute strongly to the predictive power of these models,
they are not discussed.
Table 2. Model selection statistics from logistic regression modeling of Fox Squirrel presence
on 98 golf courses in coastal South Carolina. Only models included in the 90% confidence set
are presented.
Cumulative
sum of
Model AICc AICc
# Variables KA ΔAICc weight weights
3 Presence of Fox Squirrels on nearest neighboring 2 0 0.59 0.590
course
7 Distance to edge of nearest neighboring course with 4 1.044 0.35 0.939
Fox Squirrels; total area of courses with Fox
Squirrel populations within 5 km; presence of Fox
Squirrels on the nearest neighbor course
ANumber of parameters in the model.
582 Southeastern Naturalist Vol. 9, No. 3
Discussion
The models that best predicted the presence of southeastern Fox Squirrels
on golf courses in coastal South Carolina included terms that were related
to the presence of conspecifics on the nearest neighboring golf-course and
the distance to and prevalence of those golf courses. Furthermore, the mean
distance between two neighboring courses when each had Fox Squirrels
was less compared to the distance between two neighboring courses where
only one had Fox Squirrels. Perhaps surprisingly, variables that accounted
for the amount of forested land within 1 km and 5 km of the golf course did
not have a strong relationship with Fox Squirrel presence on a golf course.
These results demonstrate that the proximity of golf courses with conspecifics
increases the probability of Fox Squirrel presence on a golf course.
Although we did not specifically assess movement patterns, the importance
of the nearest neighboring course variable suggests that golf courses
may be acting as habitat patches and that movement between these patches
may be critical for maintaining populations. For example, Fox Squirrels can
range widely and exhibit high rates of dispersal in both natural and urban
patches (Ditgen 1999, Jodice 1993). Most of our study courses, which averaged
ca. 125 ha in area, were small relative to the reported home-range size
for Fox Squirrels in similar landscapes in the southeast. For example, Ditgen
(1999) reported that home-range size of Fox Squirrels on golf courses in
southwestern Florida were as large 304 ha across genders and age groups.
The courses in that study are best characterized as open spaces within a matrix
of intense development and formed an overall landscape similar to many
of those available in our study area (e.g., the Myrtle Beach region along the
northern coast and the Hilton Head region along the southern coast). Ditgen
Table 3. Model selection statistics from logistic regression modeling of Fox Squirrel presence on
golf courses in coastal South Carolina, which did not have a Fox Squirrel population on their nearest
neighbor course (n = 35). Only models included in the 90% confidence set are presented.
Cumulative
Model AICc sum of
# Variables KA ΔAICc weight AICc weights
22 Course age 2 0 0.571 0.571
15 Area within course of coniferous, deciduous, 7 3.672 0.091 0.662
mixed and shrub/scrub forest; grass, wetland,
and open water
13 Area of all road types within the course boundary 2 5.235 0.042 0.703
16 Area of cover within 1km of course of coniferous, 6 5.239 0.042 0.745
deciduous, and scrub/shrub forest; grass, wetland,
and open water
4 Distance to nearest course with Fox Squirrels 2 5.649 0.034 0.779
19 Simpson’s diversity index for habitat 2 6.045 0.028 0.806
12 Total area on course with >50% impervious cover 2 6.155 0.026 0.833
21 Latitude of course 2 6.526 0.022 0.855
10 Total developed landcover within 1 km of course 2 6.84 0.019 0.873
11 Total developed landcover within 5 km of course 2 6.87 0.018 0.892
9 Total developed landcover on course 2 6.886 0.018 0.91
ANumber of parameters in the model.
2010 K. Meehan and P.G.R. Jodice 583
(1999) observed substantial movement among golf courses and, as in our
study, found that landscape-scale factors were more important in determining
population size on a course compared to course-scale factors.
We did observe a positive effect of individual attributes of golf courses
(i.e., factors operating at a spatial scale less than the landscape level) on Fox
Squirrel presence on courses which did not have conspecifics on their nearest
neighboring course. The best model of this subset included only a term for
the age of the golf course. The high ranking of this variable may be due to a
combination of factors. Older golf courses may provide a more stable habitat
since landscaping is more mature and development less active. The age of
the golf course also may have acted as a surrogate for the location of the golf
course in this study. Golf courses in the southern part of the state were older
on average and appeared from our survey data to have higher abundances
of Fox Squirrels (Meehan 2007). A greater frequency of occurrence of Fox
Squirrels on southern courses may ultimately reflect historic abundances,
however, as the central and southern portions of the South Carolina coast
have traditionally had the greatest density of Fox Squirrels in the state (Harrigal
1993).
Research conducted on Fox Squirrels in urban and fragmented settings
has found that a combination of landscape and patch attributes tends to
affect Fox Squirrel presence. Deuser et al. (1988) and Ditgen (1999) reported
that Fox Squirrel presence in fragmented woodlots and golf courses, respectively,
was primarily related to patch isolation and between-patch variables,
which is similar to the nearest neighboring course effect we documented.
Jodice and Humphrey (1992) and Lee et al. (2008), however, both suggested
that local habitat features, or within-patch variables such as food availability,
were important factors affecting Fox Squirrel populations. This observation
is similar to the course-level effects we observed for courses without Fox
Squirrels on their nearest neighboring course. We suggest that these two sets
of apparently conflicting results may rather be factors operating at different
spatial scales, where the ability of individuals to move among courses has
a strong effect on presence versus absence, but local habitat features have a
larger role in determining population abundance. Therefore our data should
not be taken to suggest that Fox Squirrels do not respond to habitat factors
within the boundaries of a golf course. Our inability to detect these effects
is likely due to the scale of our research, as well as our analysis of squirrel
populations at a presence/absence level.
Our data, specifically the nearest-neighboring-course effect, suggest
that movement of Fox Squirrels among golf courses in coastal South
Carolina may be important and that golf courses in this region may have a
greater opportunity to support or retain Fox Squirrel populations when the
land area surrounding or near the course also supports Fox Squirrels. If so,
the population stability of Fox Squirrels on golf courses in this region may
be enhanced by the existence of movement corridors between nearby golf
courses. This connectivity may be especially important in areas comprised
584 Southeastern Naturalist Vol. 9, No. 3
of smaller courses with apparently lower densities of Fox Squirrels, such
as those found along the northern coast of South Carolina (e.g., the Myrtle
Beach area; Meehan 2007). In areas of the state with larger courses and a
lower level of present development overall, those interested in conservation
of Fox Squirrels should consider maintaining large contiguous patches
of habitat within areas experiencing development and by clustering development
of new golf courses. Future research should investigate the
metapopulation structure of Fox Squirrels on golf courses in this region.
Furthermore, the development of a long-term monitoring plan focused on
golf course habitats should be considered.
Acknowledgments
Funding for this research was provided by the National Fish and Wildlife Foundation
Wildlife Links Program through the United States Golf Association. The US
Geological Survey, South Carolina Cooperative Fish and Wildlife Research Unit
supplied logistical support. The staff of the Waddell Mariculture Center, Bears Bluff
National Fish Hatchery, and the Belle W. Baruch Institute for Marine and Coastal
Sciences provided field housing. Thanks go to all the golf courses that participated
in the research, and especially those that allowed repeated access to their course
for surveys. This manuscript benefited from suggestions by J. Allen, S. Loeb, B.
Song, R. Applegate, and anonymous peer-reviewers for constructive comments on
the manuscript. The South Carolina Cooperative Fish and Wildlife Research Unit is
supported jointly by the US Geological Survey, the South Carolina Department of
Natural Resources, and Clemson University.
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