1. DRAFT
Report: The Impact of Recreational
Trail Development
for Human and Domestic Dog Use
on Urban Wildlife Habitat
J. Young
June 2012
NOTE: This research was not commissioned by South Fork Conservancy or Park Pride. The author
resides on Robin Lane on a lot extending to the center of the South Fork of the Peachtree Creek. He does
not assert neutrality on the issue of trail construction in all segments of the proposed corridor, and
encourages readers to review the articles cited below and form their own conclusions.

2. TABLE OF CONTENTS
1. Introduction............................................................................................................. 3
2. Abstracts of Papers ................................................................................................. 5
a. General........................................................................................................ 5
b. Mammals..................................................................................................... 7
c. Birds............................................................................................................ 9
3. Conclusions with Discussion ................................................................................ 13
a. Value of wildlife habitat ........................................................................... 13
b. Trails: Impact on wildlife.......................................................................... 13
c. Dogs: Impact on wildlife .......................................................................... 13
d. Vulnerability of stream corridor ............................................................... 14
e. Need for studies of impact on wildlilfe..................................................... 14
f. Selected rather than connected development............................................ 14
4. Recommendations................................................................................................. 15
a. Slow down the process now being pushed forward by South Fork
Conservancy. Before proceeding, provide wildlife impact studies
suitable for EPA/EPD review. .................................................................. 15
b. Give weight to neighbor knowledge of wildlife populations and the
negative impacts they have witnessed when access has been
increased. .................................................................................................. 15
c. Consider that some segments may be inappropriate for trail
development leading to a need to abandon the concept of a
connected alternative transportation system of trails................................ 15
d. Set aside sensitive South Fork segments as “no trail wildlife
preservation zones,” including the segment between Zonolite and
MNP (this segment has beach zones flanked by narrow areas
containing animal nests and burrows that are sensitive to dog
activity). .................................................................................................... 15
5. Closing Comments................................................................................................ 15
6. References:............................................................................................................ 17
DRAFT 2

3. 1. INTRODUCTION
South Fork Conservancy is promoting the development of an alternative
transportation corridor consisting of 30+ miles of connected trails along the South Fork
of Peachtree Creek in Atlanta and DeKalb County Georgia. The trails would extend from
near the beginning of the Georgia 400 expressway at I-85 to Decatur, Georgia. The trails
would pass through a number of widely varying urban environments, including woodland
wildlife habitats. See http://www.parkpride.org/get-involved/community-programs/park-
visioning#southfork.
The South Fork is part of The City of Atlanta’s FINAL APPROVED
GREENWAY ACQUISITION PLAN (GAP), approved by EPA and EPD on March 29,
2001. Wildlife habitat preservation is a repeated goal of the GAP. For example:
The term “greenway”, as used in this Greenway Acquisition Plan, means a
network of natural areas in corridors immediately adjacent to rivers or lakes and
managed for conservation, non-point source pollution abatement, and protection
of aquatic and stream corridor habitats, which are compatible with low impact
uses by the public. In other words, the term “greenway” may be interpreted to
mean a “natural stream buffer”.
The Greenway System to be implemented under this project allows the
implementation of public access facilities such as hiking trails, bicycle trails, and
canoe launches. However, only 10 percent of the area acquired under this
project may be used for public access or use facilities. Due to the potential for
human activities to adversely affect water quality and habitats, public access or
use facilities must be designed, constructed, and managed with non-point source
pollution prevention as the primary consideration.
...
The recreational benefits associated with greenways have been known for
several years and are well documented; however, the benefits associated with
the protection of water quality and aquatic and stream corridor habitats are still
unfolding and the full extent of the capacity of greenways to protect water quality
and aquatic and stream corridor habitats may not be clear for several years.
...
Other benefits associated with greenways include the following: they protect
plant and animal life within the greenway, they distance relatively impervious
surfaces from rivers and lakes, they provide space for best management
practices (BMPs), they provide effective flood control, and they control erosion.
Greenways provide a sanctuary within which living tissue live and multiply in
space and time. Some of the species living within greenways are endangered or
threatened. Greenways protect riparian corridors from human activities such as
development, recreation, and resource extraction. This in return protects species
that may be in danger of becoming extinct. Since greenways are natural buffers,
the living and non-living tissue function together as an ecosystem which is
healthy for humans and the environment.
South Fork, despite being a narrow riparian zone, does provide habitat for a range
of wildlife. Neighbors report seeing deer, opossum, coyotes, barred owls, ducks, pileated
woodpeckers, downy and redheaded woodpeckers, red tailed hawks, chipmunks,
DRAFT 3

4. snapping turtles, box turtles, blue birds, goldfinch, great blue heron, beaver, foxes,
raccoons, and fish.
The research reported below was conducted because of concerns (as referenced in
the GAP quoted above) about the impact trail development could have on some relatively
undisturbed segments of the proposed corridor, such as the South Fork between Zonolite
and the Morningside Nature Preserve (MNP). Do the recreational benefits outweigh the
environmental impact on existing wildlife? Simply assuming this is true may be a
significant error.
Furthermore, there is a concern that the serious off-leash dog problem now
existing at the Johnson/Taylor Preserve in Morningside will be duplicated at other
locations along South Fork, such as the beaches in the segment mentioned above between
Zonolite and the MNP. Neighbors living near the Johnson Taylor Nature Preserve assert
that increased human and dog recreation there has driven away nesting turtles as well as
foxes, and decreased the frequency of sightings of bird species. Serious efforts to enlist
the police and city agencies to enforce the leash law have failed.
We must face the ironic possibility that building out and using the trail plan,
instead of putting urban dwellers in more contact with nature may, like other
developments, reduce that contact by decreasing urban wildlife populations.
DRAFT 4

5. 2. ABSTRACTS OF PAPERS
Abstracts or excerpts from several research papers listed at the end of this paper are
organized by the species on which they focus in this section: a) General, b) Mammals,
and c) Birds. A Reference table of citations for seventeen research papers and articles
can be found in numbered sequence on pages 17-18.
a. General
[6] Wildlife responses to pedestrians and dogs
Miller, SG | Knight, RL | Miller, CK
Wildlife Society Bulletin [Wildl. Soc. Bull.]. Vol. 29, no. 1, pp. 124-132. 2001.
Abstract:
As participation in outdoor recreational activities escalates, land managers struggle to
develop management policies that ensure coexistence of wildlife and recreation.
However, this requires an understanding of how wildlife responds to various forms of
recreational activities and the spatial context in which the activities occur. Therefore, we
measured responses of 2 species of grassland songbirds, one species of forest songbird,
and mule deer (Odocoileus hemionus) exposed to a pedestrian, a pedestrian accompanied
by a dog on leash, and a dog alone (only for grassland birds), on and away from
recreational trails. We assessed the "area of influence" for each treatment by determining
the probability that an animal would flush or become alert (for mule deer only) given its
perpendicular distance to a trail or a line of movement in areas without trails. When
animals were disturbed, we measured flush distance (the distance between the
disturbance and the animal when flushed), distance moved, and, for mule deer, alert
distance (the distance between the disturbance and the deer when it became alert). For all
species, area of influence, flush distance, distance moved, and alert distance (for mule
deer) was greater when activities occurred off-trail versus on-trail. Generally, among on-
trail and off-trail treatments in grasslands for vesper sparrows (Pooecetes gramineus) and
western meadowlarks (Sturnella neglecta), the smallest area of influence and shortest
flush distance and distance moved resulted from the dog-alone treatment, and these
responses were greater for the pedestrian-alone and dog-on-leash treatments. In forests,
for American robins (Turdus migratorius), the area of influence, flush distance, and
distance moved did not generally differ between the pedestrian-alone and dog on- leash
treatments. For mule deer, presence of a dog resulted in a greater area of influence, alert
and flush distance, and distance moved than when a pedestrian was alone. Natural lands
managers can implement spatial and behavioral restrictions in visitor management to
reduce disturbance by recreational activities on wildlife. Restrictions on types of
activities allowed in some areas such as prohibiting dogs or restricting use to trails will
aid in minimizing disturbance. Additionally, managers can restrict the number and spatial
arrangement of trails so that sensitive areas or habitats are avoided.
[6] WILDLIFE RESPONSES TO PEDESTRIANS AND DOGS
Final Report Submitted to City of Boulder Open Space Department
Richard L. Knight and Scott G. Miller 1996
Department of Fishery and Wildlife Biology Colorado State University
Abstract:
DRAFT 5

6. We measured the responses of two grassland passerines, one forest passerine, and one
large mammal exposed to recreational treatments both on- and off-trail, including a pedestrian
alone, a pedestrian accompanied by a dog-on-leash, and a dog alone. Responses measured
included flush response (whether the animal flushed or not), flush distance (distance between
disturbance and animal when flushed), distance of flush (distance the animal moved after
flushing). All wildlife species in our study exhibited greater responses when the treatment
occurred off-trail than when on-trail. In the grasslands, the dog-alone treatment elicited the
least response by vesper sparrows (Pooecetes gramineus) and western meadowlarks (Sturnella
neglects), whereas pedestrian-alone and pedestrian accompanied by a dog-on-leash elicited
greater responses. In the forest, American robins (Turdus migratorius) responded similarly to
@ a pedestrian-alone and a pedestrian accompanied by a dog-on-leash. Mule deer (Odocoileus
hemionus) exhibited the greatest response when a pedestrian was accompanied by a dog. Our
results have important implications for the design and implementation of management policies,
such as using spatial and behavioral restrictions, to ensure the coexistence of wildlife and
recreationists .
[17] WILDLIFE RESPONSES TO RECREATION AND ASSOCIATED
VISITOR PERCEPTIONS
AUDREY R. TAYLOR1 AND RICHARD L. KNIGHT2
1Department of Fishery and Wildlife Biology, Colorado State University, Fort Collins, Colorado 80523 USA
Abstract. Outdoor recreation has the potential to disturb wildlife, resulting in energetic
costs, impacts to animals’ behavior and fitness, and avoidance of otherwise suitable habitat.
Mountain biking is emerging as a popular form of outdoor recreation, yet virtually nothing
is known about whether wildlife responds differently to mountain biking vs. more traditional
forms of recreation, such as hiking. In addition, there is a lack of information on the ‘‘area
of influence’’ (within which wildlife may be displaced from otherwise suitable habitat due
to human activities) of different forms of recreation. We examined the responses of bison
(Bison bison), mule deer (Odocoileus hemionus), and pronghorn antelope (Antilocapra
americana) to hikers and mountain bikers at Antelope Island State Park, Utah, by comparing
alert distance, flight distance, and distance moved.Within a species, wildlife did not respond
differently to mountain biking vs. hiking, but there was a negative relationship between
wildlife body size and response. We determined the area of influence along trails and offtrail
transects by examining each species’ probability of flushing as perpendicular distance
away from a trail increased. All three species exhibited a 70% probability of flushing from
on-trail recreationists within 100 m from trails. Mule deer showed a 96% probability of
flushing within 100 m of recreationists located off trails; their probability of flushing did
not drop to 70% until perpendicular distance reached 390 m. We calculated the area around
existing trails on Antelope Island that may be impacted by recreationists on those trails.
Based on a 200-m ‘‘area of influence,’’ 8.0 km (7%) of the island was potentially unsuitable
for wildlife due to disturbance from recreation.
Few studies have examined how recreationists perceive their effects on wildlife, although
this has implications for their behavior on public lands. We surveyed 640 backcountry trail
users on Antelope Island to investigate their perceptions of the effects of recreation on
wildlife. Approximately 50% of recreationists felt that recreation was not having a negative
effect on wildlife. In general, survey respondents perceived that it was acceptable to approach
wildlife more closely than our empirical data indicated wildlife would allow. Recreationists
also tended to blame other user groups for stress to wildlife rather than holding
themselves responsible.
The results of both the biological and human-dimensions aspects of our research have
implications for the management of public lands where the continued coexistence of wildlife
and recreation is a primary goal. Understanding wildlife responses to recreation and the
‘‘area of influence’’ of human activities may help managers judge whether wildlife populations
are experiencing stress due to interactions with humans, and may aid in tailoring
recreation plans to minimize long-term effects to wildlife from disturbance. Knowledge of
recreationists’ perceptions and beliefs regarding their effects on wildlife may also assist
public lands managers in encouraging positive visitor behaviors around wildlife.
[11] Paul M. Cavanagh, PhD, RECREATION IMPACTS:What Science Tells Us
About
DRAFT 6

7. Managing Conservation Lands (Presentation)
Excerpt:
• 78 Land Trusts (69.6%) identify protection of wildlife
habitat and natural resources as part of their mission
• Many have trails on their lands
• Recreation and Public Access may not be compatible with this mission
[8] Impacts to the threatened desert tortoise from dogs: a growing threat at the
urban interface in the Mojave Desert, California. Desert tortoise (Gopherus agassizii)
populations have declined for numerous reasons in recent decades to the point where
populations north and west of the Colorado River were federally listed as threatened in
1990. One important issue identified in the tortoise recovery plan is attack by domestic or
feral dogs. USGS research reveals that attacks from dogs are likely to be a growing threat
to recovery of the species. USGS scientists developed a method of grading trauma to live
tortoises using 35-mm slides and data sheets, and then retrospectively created a database
that includes more than 6,000 tortoises from more than 30 long-term and specialized
research plots in California. The data set, collected between 1977 and 2005, includes
potential source and severity of trauma. The objectives of this research were to
characterize types of trauma affecting live tortoises by size, sex, and location; determine
if signs of attacks by domestic or feral dogs could be separated from those of wild canids;
determine if types and amounts of trauma differ in tortoise populations living near towns
and settlements versus remote areas; and prepare a risk model. The scientists found that,
in general, attacks by dogs differed from attacks by wild canids in the amount and type of
scute (scale covering of the tortoise shell) removed and bone exposed, especially to the
gular horn (on the underside of the tortoise shell), which is critical for courtship,
aggression and protection. Tortoise populations most likely to be affected by dogs occur
within 2-6 kilometers of settlements and towns. The percent of tortoises with moderate to
severe trauma from predators was significantly higher at sites near settlements than in
remote areas. One tortoise population, under study since 1980 and near a settlement, also
showed significantly increased frequency in moderate to severe trauma over time Since
1994, when the Desert Tortoise Recovery Plan was published by the U.S. Fish and
Wildlife Service, urban pressures have increased on critical habitat boundaries in several
areas. Kristin Berry, Session 19, Monday, Sept. 24, 4:30 pm.
Contact: kristin_berry@usgs.gov; 951-697-6361)
b. Mammals
[14] Reed, S. E. & Merenlender, A. M. Effects of Management of Domestic Dogs and
Recreation on Carnivores in Protected Areas in Northern California. Conservation
Biology, 25, 504-513.
Abstract: In developed countries dogs (Canis lupus familiaris) are permitted to
accompany human visitors to many protected areas (e.g., >96% of protected lands in
DRAFT 7

8. California, U.S.A.), and protected-area management often focuses on regulating dogs due
to concerns about predation, competition, or transmission of disease and conflicts with
human visitors. In 2004 and 2005, we investigated whether carnivore species richness
and abundance were associated with management of domestic dogs and recreational
visitation in protected areas in northern California. We surveyed for mammalian
carnivores and human visitors in 21 recreation areas in which dogs were allowed offleash
or onleash or were excluded, and we compared our observations in the recreation areas
with observations in seven reference sites that were not open to the public. Carnivore
abundance and species richness did not differ among the three types of recreation areas,
but native carnivore species richness was 1.7 times greater (p < 0.01) and the relative
abundances of native coyotes (Canis latrans) and bobcats (Lynx rufus) were over four
times greater (p < 0.01) in the reference sites. Abundances of bobcats and all carnivores
declined as the number of visitors increased. The policy on domestic dogs did not appear
to affect species richness and abundance of mammalian carnivores. But the number of
dogs we observed was strongly associated with human visitation (R2= 0.54), so the key
factors associated with recreational effects on carnivores appear to be the presence and
number of human visitors to protected areas.
[15] Reed, S. E. & Merenlender, A. M. 2008. Quiet, Nonconsumptive Recreation
Reduces Protected Area Effectiveness. Conservation Letters, 1, 146-154.
Abstract: Protected areas around the world were created with the goals of preserving
biodiversity and providing nature-based recreation opportunities for millions of people.
This dual mandate guides the management of the majority of the world's protected areas,
but there is growing evidence that quiet, nonconsumptive recreation may not be
compatible with biodiversity protection. We combined noninvasive survey techniques
and DNA verification of species identifications to survey for mammalian carnivores in 28
parks and preserves in northern California. Paired comparisons of neighboring protected
areas with and without recreation revealed that the presence of dispersed, nonmotorized
recreation led to a five-fold decline in the density of native carnivores and a substantial
shift in community composition from native to nonnative species. Demand for recreation
and nature-based tourism is forecasted to grow dramatically around the world, and our
findings suggest a pressing need for new approaches to the designation and management
of protected areas.
[3] The Effects of Dogs on Wildlife Communities
1* 2 3
Benjamin Lenth , Mark Brennan , and Richard L. Knight
February, 2006
Final research report submitted to:
Boulder County Open Space and Mountain Parks
Abstract
Domestic dogs (Canis familiaris) are frequent visitors to open space areas, though little is
known about their ecological impacts. We studied the effects of dogs on wildlife by
comparing the activity levels of wildlife in areas that prohibit dogs, with areas that allow
dogs off-leash under “voice and sight” control. To measure wildlife activity both on trail and
up to 200 m off-trail, we used four methods: pellet surveys, scented tracking plates, remote
DRAFT 8

9. triggered cameras, and on-trail scat surveys. Additionally, in prairie dog (Cyonomys
ludocivianus) colonies we measured the distances of prairie dog burrows to the nearest trail,
and compared the density of prairie dog burrows between areas with and without dogs. The
presence of dogs along recreational trails correlated with altered patterns of habitat utilization
by several wildlife species. Mule deer (Odocoileus hemionus) activity was significantly
lower in proximity to trails in areas that allow dogs, and this effect extended at least 100 m
off-trail. Small mammals, including squirrels (Sciurus spp.), rabbits (Sylviagus spp.),
chipmunks (Eutamias spp.), and mice (Peromyscus spp., Reithrodontomys spp., Onychomys
spp., Zapus spp.), also exhibited reduced levels of activity in proximity to trails in areas with
dogs, and this effect extended at least 50 m off-trail. Furthermore, the density of prairie dog
burrows was lower within 25 m of trails in areas that allow dogs. The presence of dogs also
affected carnivore activity, although in varying ways. Red fox (Vulpes vulpes) detections
were higher in areas that allowed dogs, and bobcat (Felis rufus) detections were lower. These
findings have implications for the management of natural areas regarding dog policies,
particularly those that allow dogs off-leash.
c. Birds
[4] J. Miller et al., “Recreational trails, human activity, and nest predation
in lowland riparian areas.”
Abstract
In areas of human settlement, greenways and open-space land are often intended to serve
recreational purposes as well as provide wildlife habitat, but the compatibility of these
goals is uncertain. We examined the effect of recreational trails on the risk of nest
predation and nest predator activity at four lowland riparian sites along the Front Range
of Colorado. At one site on each of two streams, we placed a transect of artifcial nests
near a recreational trail and another transect on the opposite side of the stream. We also
placed another transect of nests at a second site on each stream that was not associated
with a recreational trail. In 1995, nests were baited with quail eggs; in 1996 a clay egg
was also added to nests to aid us in nest predator identifcation. Artifcial nests are not
perfect surrogates for natural nests, but are useful in generating hypotheses about causes
of nest failure and for detecting changes in predator assemblages. Overall, predation rates
were high (94%). There were signifcant differences in vulnerability to predation on the
different transect types, with a tendency for predation rates to increase with distance from
trails. There was a signifcant effect of time with a greater risk of predation in 1996. In
1996, 83% of the clay eggs that were recovered showed signs of predation. House Wrens
destroyed 11% of the clay eggs; impressions from Black-billed Magpies, Blue Jays, and
Common Grackles were found on 69%; mice preyed on 25%; and squirrels on 12% of the
eggs. Birds attacked more nests near trails than away from trails, whereas mammals
appeared to avoid nests near trails to some extent. These results support the contention
that recreational trails and human activity may affect nesting success for some species,
and suggest that patterns of nest predation reflect the unique, and sometimes, counter-
intuitive responses of individual predator species. Rather than relying on simplistic
DRAFT 9

10. assumptions about the compatibility of recreation and wildlife, it is important to consider
how individual species respond to the habitat alteration and human activity associated
with trails when deciding where trails should be located and in developing overall
conservation strategies in human-dominated areas.
[5] INFLUENCE OF RECREATIONAL TRAILS ON
BREEDING BIRD COMMUNITIES
SCOTT G. MILLER,1,3 RICHARD L. KNIGHT,1 AND CLINTON K. MILLER2,4
1Department of Fishery and Wildlife Biology, Colorado State University, Fort Collins, Colorado 80523 USA
2Department of Open Space, 66 S. Cherryvale Road, Boulder, Colorado 80303 USA
Abstract. We investigated the influence of recreational trails on breeding bird
communities in forest and mixed-grass prairie ecosystems in Boulder County, Colorado,
United States, during 1994 and 1995. Species composition, nest predation, and brood
parasitism by Brown-headed Cowbirds (Molothrus ater) were examined near and away
from existing recreational trails. Bird species composition was altered adjacent to trails in
both ecosystems. Generalist species were more abundant near trails, whereas specialist
species were less common. Within the grassland ecosystem, birds were less likely to nest
near trails. Within both ecosystems, nest predation was greater near trails. In forests, the
rate of brood parasitism was not influenced by trails. No brood parasitism was found in
the grassland ecosystem. Our results may be useful to natural-lands managers who must
implement management policies regarding the spatial arrangement of trails and trail-use
restrictions.
[12] Un-happy Trails?
By Mary Hobbs
Biodiversitynotes -- Newsletter of the Biodiversity Project
(http://www.biodiversityproject.org/newsletters/newssp01.htm#trails)
spring 2001
Editor's Note: People are an integral part of many landscapes, and as our
feature article shows, we can affect the land and the life it supports for
good as well as for ill. Yet sometimes even our most subtle activities can
have an impact on our neighboring wildlife. As more and more of us visit
local reserves, parks, forests and wilderness areas every year, it becomes
increasingly important to measure the effects, so we can design trails and
other recreational activities to minimize human impact on sensitive
species.
We're all familiar with the negative impact of roads and motorized off-road
vehicles on wildlife, but few of us stop to consider whether a walk in the
woods has consequences for resident species.
Researchers from Colorado State University (CSU) and the City of Boulder
Open Space Department investigated the effects of recreational trails,
hikers, and dogs on local bird and deer populations. Scott Miller and Dr.
Richard Knight of CSU, and Clinton Miller of the City of Boulder conducted
two separate studies to assess impacts of recreational trails and pedestrian
DRAFT 10

11. traffic on resident species.
A 1994-95 study sought to determine whether bird species diversity,
composition and abundance differed based on proximity to hiking trails. The
researchers found a greater abundance of some specialized species farther
from established human trails. In the grassland ecosystem three bird species
were found in greater abundance on the control sites (where no trails existed): western
meadowlark, vesper sparrow, and grasshopper sparrow. Similarly, five forest species
were more abundant where no trails existed, including the chipping sparrow and the
pygmy nuthatch. Not only were a greater number of species found where no trails
existed, but, the number of individual birds increased relative to distance from the trails.
Additionally, nest survival-the successful fledgling of young birds-also increased farther
from hiking trails.
Not all species suffered from proximity to trails. Generalists, including American robins
and black-billed magpies (a nest predator), did better the closer they were to human
paths.
A 1996 study concentrated on four particular species: three songbird species and mule
deer. The researchers measured the response of these species to three different
"treatments"-solitary pedestrians, a pedestrian accompanied by a dog on a leash, and a
dog alone - both on and off trails. In this study, the researchers found that there was a
significant difference in wildlife response near trails. Moreover, off-trail intruders
negatively affected all four target species.
This doesn't mean that people can't experience or enjoy parks and natural places. But it
does mean that we should stay on trails and be sensitive to the effects we (and our pets)
have on local wildlife. In addition, both studies call on natural resource managers to
reduce the effect trails have on wildlife through public education and to concentrate trails
in particular areas to minimize habitat fragmentation.
[13] Lafferty, K. D., Goodman, D. & Sandoval, C. P. 2006. Restoration of
breeding by snowy plovers following protection from disturbance.
Biodiversity and Conservation 15, 2217-2230. http://www.werc.usgs.gov/lafferty
Abstract: Promoting recreation and preserving wildlife are often dual missions for land
managers, yet recreation may impact wildlife. Because individual disturbances are
seemingly inconsequential, it is difficult to convince the public that there is a
conservation value to restricting recreation to reduce disturbance. We studied threatened
western snowy plovers (Charadrius alexandrinus nivosus) at a public beach (Sands
Beach, Coal Oil Point Reserve) in Santa Barbara, California (USA) before and during a
period when a barrier directed foot traffic away from a section of upper beach where
snowy plovers roost. The barrier reduced disturbance rates by more than half. Snowy
plovers increased in abundance (throughout the season) and their distribution contracted
to within the protected area. Snowy plovers that were outside the protected area in the
morning moved inside as people began using the beach. Experiments with quail eggs
DRAFT 11

12. indicated an 8% daily risk of nest trampling outside the protected area. Before protection,
plovers did not breed at Coal Oil Point. During protection, snowy plovers bred in
increasing numbers each year and had high success at fledging young. These results
demonstrate how recreational disturbance can degrade habitat for shorebirds and that
protecting quality habitat may have large benefits for wildlife and small impacts to
recreation.
Lafferty, K. D. 2001. Disturbance to wintering western snowy plovers.
Biological Conservation 101:315-325.
Abstract: Use of a Santa Barbara beach by people and birds varied in both time and
space. There were 100 birds, 18 people and 2 dogs per kilometer. Bird density varied
primarily with the season and tide while human activity varied most between weekend
and weekday. Bird distributions along the beach were determined mainly by habitat type
(particularly a lagoon and exposed rocky intertidal areas) For crows and western gulls,
there was some evidence that access to urban refuse increased abundance. Interactions
between birds and people often caused birds to move or fly away, particularly when
people were within 20 m. During a short observation period, 10% of humans and 39% of
dogs disturbed birds. More than 70% of birds flew when disturbed. Bird species varied in
the frequency that they were disturbed, partially because a few bird species foraged on
the upper beach where contact with people was less frequent. Most disturbances occurred
low on the beach. Although disturbances caused birds to move away from humans, most
displacement was short enough that variation in human activity did not alter large-scale
patterns of beach use by the birds. Birds were less reactive to humans (but not dogs)
when beach activity was low.
Off-Leash Dog Enforcement – Raleigh, NC
(Anecdotal email from Chris Moorman, used by permission)
Jeff,
Don't know what responses you've received so far, but please see attached a couple of
relevant documents. We had an "unleashed dog problem" at our university research and
demo forest in the Raleigh, NC city limits. We tried everything but dogs remained
unleashed despite a clearly advertised leash law. During this time, we saw a decline in
American Woodcock, a ground-nesting bird. Eventually, dogs were banned from the
forest and woodcock returned. Unfortunately, we have no defendable data to support our
observations.
Good luck,
Chris M.
DRAFT 12

13. 3. CONCLUSIONS WITH DISCUSSION
a. Value of wildlife habitat
Preservation of wildlife and its habitat along South Fork is a worthwhile and
important goal as expressed by neighbors and adopted in the CITY OF ATLANTA
FINAL APPROVED GREENWAY ACQUISITION PLAN. [1] Urban wildlife habitat is
a scarce resource that should be carefully protected. No type of development that could
impact it should proceed without benefits that heavily outweigh preservation.
b. Trails: Impact on wildlife
Even quiet recreational development such as a trail generally results in decreased
abundance of wildlife. [2, 5, 7, 10, 11, 12, 14, 15]
i. “Our results indicate that trails affect the
distribution and abundance, as well as the reproductive
success, of bird species . . .” [5]
c. Dogs: Impact on wildlife
The presence of dogs on leash or off leash significantly increases the negative
impact on wildlife habitat. [2, 3, 5, 6, 8, 11, 14]
i. “Areas with dogs had:
– 35% reduction in bird diversity
– 41% reduction in abundance
• “results…support the long-term prohibition of
dog walking from sensitive conservation areas” [11]
ii. “The presence of domestic dogs may introduce diseases or parasites to small
mammals, and the burrows of fossorial mammals can be physically damaged as a
result of domestic dogs (Stuht and Youatt 1972, Thorne et al. 1982, Durden and
Wilson 1990). In addition, dogs walking across burrows caused alarm reactions
(Mainini et al. 1993). In the case of birds, the presence of dogs may flush
incubating birds from nests (Yalden and Yalden 1990), disrupt breeding displays
(Baydack 1986), disrupt foraging activity in shorebirds (Hoopes 1993), and disturb
roosting activity in ducks (Keller 1991). Many of these authors indicated that dogs
with people, dogs on-leash, or loose dogs provoked the most pronounced
disturbance reactions from their study animals.” [2]
iii. “Keller (1991) found that ducklings were disturbed while roosting on the
shoreline and while feeding in water. The shore-based activities (fishing, people
walking, dogs) caused more disturbance than water-based activities (windsurfing,
boating). Disturbance affected the activity of young eiders for up to 35 minutes.
Keller (1991) reported that small ducklings experienced a numerical increase in
predator encounters during the first 5 minutes post-disturbance.” [2]
DRAFT 13

14. iv. Local experience has shown that posting leash law notices at trailheads simply
does not deter people from breaking the law in preservation areas.
d. Vulnerability of stream corridor
South Fork is a narrow riparian zone in which the stream and wetland ecosystem
are vulnerable because of the small scale. [2, 4, 5]
i. Fragmentation of the habitat [5, 12] seems likely.
ii. Unpredictable flooding resulting from upstream human developments already
stresses wildlife habitats along the creek [4].
iii. Many of the areas analyzed in the studies mentioned below are much larger than
the woodland borders of the South Fork wetland corridor. It is possible that the
South Fork wetland corridor, being quite narrow in some segments, is more
sensitive than the areas studied to the recreational impacts found by the authors of
these studies.
e. Need for studies of impact on wildlilfe
Developers like South Fork Conservancy and managers who propose to open up
sensitive wildlife habitats should proceed only after thorough and adequate studies of the
development’s impact on wildlife preservation, especially in light of required approval by
EPA and EPD pursuant to the GAP. [1, 3, 4, 15, 17]
i. “there is growing evidence that quiet, nonconsumptive recreation may not be
compatible with biodiversity protection.” [15]
ii. Locating trails and seeking neighborhood commentary therefore is premature
without providing adequate information concerning the impact on wildlife habitats.
[1, 3, 4, 15, 17]
f. Selected rather than connected development
Trail development in South Fork should omit sensitive wildlife habitats that
presently experience little human or dog visitation. [4, 5, 6, 11, 12, 16]
i. “Rather than relying on simplistic assumptions about the compatibility of
recreation and wildlife, it is important to consider how individual species respond to
the habitat alteration and human activity associated with trails when deciding where
trails should be located and in developing overall conservation strategies in human-
dominated areas.” [4]
DRAFT 14

15. ii. “managers can restrict the number and spatial arrangement of trails so that
sensitive areas or habitats are avoided” [6]
iii. “[referenced] studies call on natural resource managers to reduce the effect trails
have on wildlife through public education and to concentrate trails in particular
areas to minimize habitat fragmentation” [12]
iv. “Consolidation of trails to certain areas (e.g., edges of forests and grasslands)
will reduce the fragmentation of large blocks of habitat, maintaining less-disturbed
areas for species sensitive to fragmentation.” [5]
4. RECOMMENDATIONS
a. Slow down the process now being pushed forward by South Fork
Conservancy. Before proceeding, provide wildlife impact studies suitable for
EPA/EPD review.
b. Give weight to neighbor knowledge of wildlife populations and the
negative impacts they have witnessed when access has been increased.
c. Consider that some segments may be inappropriate for trail
development leading to a need to abandon the concept of a connected alternative
transportation system of trails.
d. Set aside sensitive South Fork segments as “no trail wildlife
preservation zones,” including the segment between Zonolite and MNP (this
segment has beach zones flanked by narrow areas containing animal nests and
burrows that are sensitive to dog activity).
5. CLOSING COMMENTS
Looking for appropriate locations for new parklands in Atlanta is a worthwhile
project. However, benefits to human recreation should not automatically be assumed to
trump potential negative impacts on quality of life and wildlife habitats. The author
believes that the projected “transportation” use of a hiking trail has been exaggerated and
should have a low priority when it would have to disrupt scarce urban wildlife habitat.
Providing an experience of the natural world does not require a connected 30 mile trail
and can be done selectively so as not to disturb habitats.
It appears the area covered by the South Fork Conservancy proposal does contain
segments that are less sensitive to habitat disruption and might be used, subject to close
neighbor approval, for parks, including offleash dog parks.
DRAFT 15

16. But if the entire 30 mile corridor is developed, would the red-tailed hawks and
owls not have enough prey? Would the ducks be frightened away from their mating and
nesting grounds? Would dogs dig up small animal burrows and destroy nests along the
trail? Would the trail become a coyote highway leading to an abnormal lessening of
animal and bird populations along the trail? None of these potential results should be
ignored.
The author does not believe that a potential for property value increases at
locations near but not along trails should outweigh wildlife preservation concerns.
Studies may assert a correlation between parks and economic development in the context
of property values, but these studies can be inapposite when they relate to areas trying to
bring in developers of subdivisions, apartment complexes and shopping centers. Of
course people want to be within walking distance of a park. The South Fork proposal,
however, covers considerable territory in which residents are already within walking
distance of parks. There are park-deficient areas of southwest and northwest Atlanta
where public and donated money for parks could be focused to improve the city’s rating
for walking access to parks that probably could be located outside of sensitive riparian
habitats.
Finally, the present proposal is not a restoration of existing parks like the
Olmstead Linear Park project in Druid Hills. In contrast, a continuous 30+ mile trail
would add significant disruption to wildlife habitats in some segments of the proposed
route along South Fork.
DRAFT 16

17. 6. REFERENCES:
1. CITY OF ATLANTA FINAL APPROVED GREENWAY ACQUISITION
PLAN (GAP), approved by EPA and EPD on March 29, 2001
http://www.cleanwateratlanta.org/greenway/GreenwayPlan/default.htm.
2. C. Sime, “DOMESTIC DOGS IN WILDLIFE HABITATS
EFFECTS OF RECREATION ON ROCKY MOUNTAIN WILDLIFE” (Chapter
6) http://joomla.wildlife.org/Montana/images/Documents/8dogs.pdf.
3. B. Lenth, et al., “ The Effects of Dogs on Wildlife Communities,” Feb. 2006,
Final research report submitted to Boulder County Open Space and Mountain
Parks,
4. James R. Miller, N. Thompson Hobbs, Department of Biology and Graduate
Degree Program in Ecology, Colorado State University, “Recreational trails,
human activity, and nest predation in lowland riparian areas,” Landscape and
Urban Planning 50 (2000) 227-236.
5. S. Miller, et al., “INFLUENCE OF RECREATIONAL TRAILS ON BREEDING
BIRD COMMUNITY,” Ecological Applications, 8(1), 1998, pp. 162–169.
6. S. Miller, et al., “Wildlife responses to pedestrians and dogs,” Wildlife Society
Bulletin Vol. 29, no. 1, pp. 124-132. 2001.
http://www.friendsofboulderopenspace.org/documents/dogs_wildlife_responses.p
df
7. K. Lafferty, USGS, “Adaptive management of Western Snowy Plovers at Coal
Oil Point Reserve (Presentation)
http://www.southbayrestoration.org/science/PAW/docs/Lafferty%20Talk%20on%
20Snowy%20Plovers.pdf. See also,
coaloilpoint.ucnrs.org/Docs/COPRReport2001-04.doc.
8. K. Berry, “Impacts to the threatened desert tortoise from dogs: a growing threat
at the urban interface in the Mojave Desert,
California.” http://www.usgs.gov/newsroom/article.asp?ID=1785#.T8Ja7-3Da20
9. S. Anderson, “Recreational Disturbance and Wildlife Populations.” (Chapter 9).
http://www.cof.orst.edu/cof/teach/fs453/Anderson_Recreational%20Disturbance
%20and%20Wildlife%20Populations.pdf.
10. Boyle, S. A., and F. B. Samson. 1985. Effects of nonconsumptive recreation on
wildlife: a review. Wildlife Society Bulletin 13:110–116. [First page].
11. Paul M. Cavanagh, PhD, RECREATION IMPACTS:What Science Tells Us
About Managing Conservation Lands (Presentation) [search: recreation impacts
Cavanagh]
12. M. Hobbs, “Un-happy Trails?” Biodiversitynotes -- Newsletter of the Biodiversity
Project, spring 2001
13. Lafferty et al., “Restoration of breeding by snowy plovers following protection
from disturbance,” Biodiversity and Conservation 15, 2217-2230.
14. Reed, S. E. & Merenlender, A. M. “Effects of Management of Domestic Dogs
and Recreation on Carnivores in Protected Areas in Northern California,”
Conservation Biology, 25, 504-513. [Abstract only reviewed]
DRAFT 17

18. 15. Reed, S. E. & Merenlender, A. M. 2008. “Quiet, Nonconsumptive Recreation
Reduces Protected Area Effectiveness,” Conservation Letters, 1, 146-154.
[Abstract only reviewed]
16. Knight, et al., “WILDLIFE RESPONSES TO PEDESTRIANS AND DOGS,”
Final Report Submitted to City of Boulder Open Space Department 1996
17. Taylor, et al., WILDLIFE RESPONSES TO RECREATION AND
ASSOCIATED VISITOR PERCEPTIONS
Acknowledgement: The author appreciates the assistance of members of The Wildlife
Society’s Urban Wildlife Working Group in locating many of these references.
DRAFT 18