Domestic dogs threaten endangered species worldwide

The bark side: domestic dogs threaten endangered species worldwide 

Humans and their canine companions share many close bonds. Wolves (Canis lupus) were the first animal domesticated by people, some time between 15,000 and 50,000 years ago. 

There are now an estimated 1 billion domestic dogs across their near-global distribution.

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Vagrant dogs the most harmful disturbance to great bustard in central Spain

Sastre, P., Ponce, C., Palacín, C., Martín, C. A., & Alonso, J. C. (2009). Disturbances to great bustards (Otis tarda) in central Spain: human activities, bird responses and management implications. European Journal of Wildlife Research, 55(4), 425-432.


We investigated the effects of human activities on the behaviour of great bustards (Otis tarda) in a Special Protection Area in central Spain. We recorded 532 disturbances, at a rate of 0.93 disturbances per hour, a high value compared to other studies. Escape (flight/running) was observed more often than alert. Flight was more frequent than running. Car traffic and walkers were the main sources of disturbance. Motorcyclists, dogs, helicopters and aeroplanes were also harmful in relation to their abundance and time of permanence. Farming and shepherding produced few disturbances and usually did not cause a flight response. These activities are thus considered compatible with the conservation of the great bustards. Hunting caused an increase in the frequency of disturbance on weekends and holidays with respect to working days. We propose access restrictions to car traffic and helicopters/airplanes and hunting limitations in those areas more frequently used by the species.

People and dogs disturbing birds on the beach

Lafferty, K. D. (2001). Birds at a Southern California beach: seasonality, habitat use and disturbance by human activity. Biodiversity & Conservation, 10(11), 1949-1962.

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.

Human and dog disturbance to shorebirds

McCrary, M. D., & Pierson, M. O. (2000). Influence of human activity on shorebird beach use in Ventura County, California. In Proceedings of the fifth California Islands symposium (pp. 424-427).

We studied the potential influence of human and dog activity on shorebird abundance at 13 sandy beaches in Ventura County, California. The 13 study beaches were randomly selected, and each beach was 1 km long. From June 1994 to May 1997, we counted all shorebirds, humans and dogs at each beach once per month for a total of 36 counts. We found no significant relationship between instantaneous counts of either shorebirds and human or dogs. However, there was a significant relationship among the 13 beaches between total shorebird and human use. The beaches with the greatest number of shorebirds (Ormond Beaches 1 through 3) were among those with the lowest number of humans. The results suggest that inaccessibility to humans may be an important aspect of shorebird habitat quality. Relatively undisturbed sandy beaches are quite rare in southern California, and the inaccessibility of the few remaining undisturbed beaches should be maintained. 

Dogs disturbing wintering plovers

Lafferty, K. D. (2001). Disturbance to wintering western snowy plovers.Biological Conservation, 101(3), 315-325.

In order to better understand the nature of disturbances to wintering snowy plovers, I observed snowy plovers and activities that might disturb them at a beach near Devereux Slough in Santa Barbara, California, USA. Disturbance (activity that caused plovers to move or fly) to wintering populations of threatened western snowy plovers was 16 times higher at a public beach than at protected beaches. Wintering plovers reacted to disturbance at half the distance (∼40 m) as has been reported for breeding snowy plovers (∼80 m). Humans, dogs, crows and other birds were the main sources of disturbance on the public beach, and each snowy plover was disturbed, on average, once every 27 weekend min and once every 43 weekday min. Dogs off leash were a disproportionate source of disturbance. Plovers were more likely to fly from dogs, horses and crows than from humans and other shorebirds. Plovers were less abundant near trail heads. Over short time scales, plovers did not acclimate to or successfully find refuge from disturbance. Feeding rates declined with increased human activity. I used data from these observations to parameterize a model that predicted rates of disturbance given various management actions. The model found that prohibiting dogs and a 30 m buffer zone surrounding a 400 m stretch of beach provided the most protection for plovers for the least amount of impact to beach recreation.

An integrated assessment of the impact of wild dogs in Australia

Wicks, S., Mazur, K., Please, P., Ecker, S., & Buetre, B. (2014). An integrated assessment of the impact of wild dogs in Australia. ABARES Research report no. 14.4, Canberra.

Wild dogs are a significant pest animal in Australia. They are widespread in Queensland, the Northern Territory and much of Western Australia and South Australia, as well as being present in parts of New South Wales and Victoria. Wild dogs are known to have a significant detrimental effect on the agricultural sector (market impacts), but they also cause non-market impacts in terms of adverse social impacts and environmental damage. These impacts are described in more detail below.

 

The effect of design, and dogs, on bird species on urban parks

Paker, Y., Yom-Tov, Y., Alon-Mozes, T., & Barnea, A. (2013). The effect of plant richness and urban garden structure on bird species richness, diversity and community structure. Landscape and Urban Planning.

Urban green areas improve the standard of living in cities and affect people's attitude to nature and conservation. Zoological knowledge may provide data that will help designers to enhance bird diversity in gardens. We studied the effect of plant species richness and structure on bird species richness, diversity and community structure in 25 public gardens in Tel-Aviv city and, neighboring suburbs, Israel. A total of 65 bird species were observed, of which nine were urban, exploiters or alien species. These latter species composed 54% of all individuals seen. Additional 13 bird species, mostly migrants, were observed in gardens further from the observation fixed radius. We found that shrubs species richness positively affected bird species diversity. Most bird species were found where trees and shrubs species richness was high, and trees and lawn cover were medium or low. High trees or high lawn cover attracted only a few bird species, mostly aliens and urban exploiters. Native birds preferred to forage on native trees and alien birds preferred to feed on alien trees. Bird species diversity was higher during spring and fall because of the presence of migrating bird species. Dogs and people had a negative effect on bird presence. Accordingly, we recommend that when planning new gardens, designers will avoid large lawns, prefer diverse and dense shrubberies, native trees, and will create some areas that will not be accessible to dogs and people. Finally, we emphasize the importance of multidisciplinary studies conducted in collaboration between landscape designers and zoologists.

Fragmentation and disturbance effect on the impact of feral predators in Australia

May, S. A., & Norton, T. W. (1996). Influence of fragmentation and disturbance on the potential impact of feral predators on native fauna in Australian forest ecosystems. Wildlife Research, 23(4), 387-400.

The current knowledge is reviewed of the diet and predator–prey relationships of the feral cat (Felis catus), fox (Vulpes vulpes) and dingo (Canis familiaris dingo) (including wild dogs). The effect of forest fragmentation by roads on the use of native forest ecosystems by these species and the significance of this for native fauna is considered. The cat, fox and dingo are significant predators in Australia that interact with native fauna in various ways, including predation, competition for resources, and transmission of disease. On the basis of current knowledge, it is clear that the nature and impact of predation by the cat, fox and dingo on native fauna are primarily determined by prey availability, although there are exceptions to this rule. Generally, dingoes prey upon large to medium-sized prey species (e.g. wallabies, common wombats, and possums), foxes prey upon medium-sized to small prey (e.g. possums and rats) and consume a significant component of scavenged material and vegetation, while cats also prey upon medium-sized to small prey, but may have a greater proportion of reptiles and birds in their diet. The cat is generally considered to be an opportunistic predator and to have contributed to the demise of a number of mammals. The fox is considered more of a threat to small native mammals and it has been asserted that all species of mammals that fall within the critical weight range (CWR) of 120–5000 g are at risk of local extinction when the fox is present. The severity of the impact of the dingo upon the native fauna is considered to be minimal, at least in comparison with the impact that the cat and fox can have on populations. The dingo is not considered a threat to CWR mammals in undisturbed environments. The fox, feral cat and dingo are all considered to have the ability to selectivity prey upon species and, to some extent, individual sexes and age-classes of a number of larger prey species.

Although many of Australia's forested areas are relatively heavily fragmented by roads, there are no published studies specifically investigating the use of roads by feral predators. Information on the distribution and abundance of foxes, cats and dingoes in these ecosystems, their ecology and their impact on native fauna is particularly limited. Further, the extent to which roads influence the distribution and abundance of these species and the consequences of these for native fauna are poorly known. One of the most important research needs is to establish the relative impact that exotic predators may have on native fauna under varying degrees of road construction within native forests. For example, are areas with and without roads in forests used differently by exotic predators and what is the significance of this in terms of the potential impact on fauna? The extent to which feral predators forage away from roads needs further investigation, as does the rates of predation within edges, because this may have several consequences for the design, location and size of retained strips and wildlife corridors as well as restoration programmes. Further observations on regional differences influencing predator–prey interactions are required, as is research on the potential impacts on native fauna resulting from prey selection in forests subjected to various degrees of fragmentation and modification.

Perception of threatened species management on urban beaches

Maguire, G. S., Rimmer, J. M., & Weston, M. A. (2013). Stakeholder Perceptions of Threatened Species and Their Management on Urban Beaches.Animals, 3(4), 1002-1020.

Simple Summary: Coastal urbanisation brings humans into contact with beach-dwelling wildlife. Where wildlife are disturbance prone, active management is required to promote coexistence between beach-goers and endangered wildlife. Coexistence relies on people adopting wildlife-sensitive behaviours. This study examines factors, which influence people’s awareness and perceptions of threatened species management in southern Australia, using Hooded Plover Thinornis rubricollis management as a model. The inconvenience experienced by beach goers in regard to plover management was low. Awareness and support for plover conservation were high. Frequency of beach use, whether a person was a dog walker, and awareness of the species and its plight, influenced perceptions.


Abstract: We surveyed 579 recreationists regarding management of the threatened, beach-dwelling Hooded Plover Thinornis rubricollis. We postulated that: (1) lower awareness of the species and higher ‘inconvenience’ of management would engender less favourable perceptions of conservation and management; and (2) that frequency of beach use and dog ownership may mediate perceptions and levels of awareness and inconvenience. Overall, inconvenience was low while awareness and support for plover conservation were high.
Education and awareness strategies were considered less effective than regulations; exclusion and regulations were considered less desirable than on-ground protective measures. Awareness, frequency of beach use and dog walking did not influence the perceived effectiveness of different managements. More frequent beach users had greater awareness of the species and their plight but reported greater inconvenience associated with management. Respondents with high awareness rated the severity of human-related threats higher; low awareness was associated with more inconvenience associated with on-ground protection, and exclusion and regulations. Dog walkers reported more inconvenience associated with exclusions and regulations than non-dog walkers. Dog walkers who used the beach infrequently rated threats significantly higher than frequent beach users. Conservation and education strategies could usefully be tailored to beach users’ level of use and pet ownership.

Domestic dogs in Wildlife habitats

Sime, C. A. 1999. Domestic Dogs in Wildlife Habitats. Pages 8.1-8.17 in G. Joslin and H. Youmans, coordinators. Effects of recreation on Rocky Mountain wildlife: A Review for Montana. Committee on Effects of Recreation on Wildlife, Montana Chapter of The Wildlife Society. 307pp.

It is difficult to segregate human demographic trends from trends in rural development and outdoor recreational participation in settings like the West where they appear to be interrelated. One extension of human recreation in wildlife habitats is the effect of disturbance, harassment, displacement, or direct mortality of wildlife attributable to domestic dogs that accompany recreationists. At some level, domestic dogs still maintain instincts to hunt and/or chase. Given the appropriate stimulus, those instincts can be triggered in many different settings. Even if the chase instinct is not triggered, dog presence in and of itself has been shown to disrupt many wildlife species. Authors of many wildlife disturbance studies concluded that dogs with people, dogs on-leash, or loose dogs provoked the most pronounced disturbance reactions from their study animals. During winter, concerns are primarily related to human activity on ungulate winter ranges. Dogs extend the zone of human influence when off-leash. Many ungulate species demonstrated more pronounced reactions to unanticipated disturbances, as a dog off-leash would be until within very close range. In addition, dogs can force movement by ungulates (avoidance or evasion during pursuit), which is in direct conflict with overwinter survival strategies which promote energy conservation. During summer, concerns are primarily related to the birth and rearing of young for all wildlife species. Dogs are noted predators for various wildlife species in all seasons. Domestic dogs can potentially introduce diseases (distemper, parvovirus, and rabies) and transport parasites into wildlife habitats. While dog impacts to wildlife likely occur at the individual scale, the results may still have important implications for wildlife populations. For most wildlife species, if a “red flag” is raised by pedestrian-based recreational disturbance, there could also be problems associated with the presence of domestic dogs. Managers may consider the following when evaluating recreational impacts of dogs in wildlife habitats: species biology, reproductive potential, abundance, density, distribution, degree of habitat specificity or reliance on certain habitat components, and predisposition and sensitivity to disturbance by other agents. This information is intended to increase awareness among natural resource professionals and the public about the potential implications of uncontrolled domestic dogs in wildlife habitats and to encourage responsible outdoor recreation ethics.

Behaviour of deers chased by hunting dogs

Sweeney, J. R., Marchinton, R. L., & Sweeney, J. M. (1971). Responses of radio-monitored white-tailed deer chased by hunting dogs. The Journal of Wildlife Management, 35 (4): 707-716.

Studies were conducted on three separate areas-Auburn, Alabama; Eglin Air Force Base, Florida; and Savannah River Plant, South Carolina-to determine the responses of white-tailed deer (Odocoileus virginianus) to chasing by hunting dogs (Canis familiaris). Deer chosen for harassment were animals that had been studied by telemetry until normal behavior, movement patterns, and ranges were delineated. In every chase the deer escaped the hounds, and all deer remained in good physical condition throughout the study. Behavior that resulted in escape was classified into five categories: holding, distance running, circuitous zigzag running, separating from a group, and using escape habitat. Chases averaged 33 minutes in duration and 2.4 miles in distance with maximums of 155 minutes and 13.4 miles recorded. Deer in high populations were more difficult to chase for extended periods than those in low populations. Although the deer did not require water for escape, they usually selected swamps or other bodies of water when these were available. The deer could readily be chased out of their home ranges, but usually they returned in 1 day or sooner.

Interactions among dogs, people and wildlife

Bekoff, M., & Meaney, C. A. (1997). Interactions among dogs, people, and the environment in Boulder, Colorado: A case study. Anthrozoos: A Multidisciplinary. Journal of The Interactions of People & Animals, 10(1), 23-31.

From September 1995 to April 1996 we studied interactions among dogs, people, and the environment in Boulder, Colorado. Data on behavioral disturbances by off-leash dogs who were accompanied by a person were collected with respect to dog-dog and dog-human interactions, dog-wildlife encounters, dogs trampling vegetation, and dogs entering and disturbing bodies of water. A questionnaire also was administered. Behavioral data showed that off-leash dogs generally did not travel far off trail, that when they did it was for short periods of time, and that they rarely were observed to chase other dogs, disturb people, chase wildlife, destroy vegetation, or enter bodies of water. Results from analyses of the questionnaire (skewed toward non-dog owners) showed that dog owners and non-dog owners agreed that people were more disruptive to the environment than dogs and that unruly people were more problematic than unruly dogs. We conclude that the well-being and interests of dogs should not summarily and dismissively be compromised when dogs and people attempt to share limited space that can be used by all parties for recreational purposes. Indeed, a higher percentage of people reported that the quality of dogs' experience of the outdoors would be compromised more than their own enjoyment if dogs could not walk off-leash in areas where this is currently permitted. The methods used and the results from this case study can serve as a model for other locations in which dogs and people compete for limited spatial resources.

BOOK: Free-Ranging Dogs and Wildlife Conservation

Gompper, M.E. (Ed.) 2013. Free-Ranging Dogs and Wildlife Conservation. Oxford University Press. 

Table of contents

Luigi Boitani: Foreword
Matthew E. Gompper: Introduction: Outlining the Ecological Influences of a Subsidized, Domesticated Predator
1: Matthew E. Gompper: The Dog-Human-Wildlife Interface: Assessing the Scope of the Problem
2: Euan G. Ritchie, Mike Letnic, Christopher R. Dickman and Abi Tamim Vanak: Dogs as Predators and Trophic Regulators
3: Abi Tamim Vanak, Christopher R. Dickman, Eduardo A. Silva-Rodriguez, James R. A. Butler and Euan G. Ritchie: Top-dogs and Under-dogs: Competition between Dogs and Sympatric Carnivores
4: Michael A. Weston and Theodore Stankowich: Dogs as Agents of Disturbance
5: James R.A. Butler, John D.C. Linnell, Damian Morrant, Vidya Athreya, Nicolas Lescureux and Adam Mckeown: Dog Eat Dog, Cat Eat Dog: Social-ecological Dimensions and Implications of Dog Predation by Wild Carnivores
6: Darryn Knobel, James R. A. Butler, Tiziana Lembo, Rob Critchlow and Matthew E. Gompper: Dogs, Disease, and Wildlife
7: Jennifer A. Leonard, Jorge Echegaray, Ettore Randi and Carles Vilà: Impact of Hybridization with Domestic Dogs on the Conservation of Wild Canids
8: Ryan H. Boyko and Adam R. Boyko: Dog Conservation and the Population Genetic Structure of Dogs
9: Kurt VerCauteren, Michael Lavelle, Thomas M. Gehring, Jean-Marc Landry and Laurie Marker: Dogs as Mediators of Conservation Conflicts
10: Deborah A. (Smith) Woollett, Aimee Hurt and Ngaio Richards: The Current and Future Roles of Free-ranging Detection Dogs in Conservation Efforts
11: Jeremy Koster and Andrew Noss: Hunting Dogs and the Extraction of Wildlife as a Resource
12: Kelly K. Miller, Euan G. Ritchie and Michael A. Weston: The Human Dimensions of Dog-Wildlife Interactions

Dogs and cats in the mammal assemblage in a urban forest patch in Brazil

Bernardo, P. V. D. S., & Melo, F. R. D. (2013). Assemblage of medium and large size mammals in an urban Semideciduous Seasonal Forest fragment in Cerrado biome. Biota Neotropica, 13(2), 76-80.

Nowadays, the processes of deforestation and loss of habitats represent a major threat to many species of mammals. These processes cause changes in natural landscapes by decreasing area, connectivity, and fragment size, and increasing edge effects and number of fragments. Understanding which and how many species persist in disturbed fragments may indicate the species' minimum requirements and might contribute to their conservation. Here we show how the mammalian fauna of medium and large size (higher than 1 kg) are structured in a semideciduous seasonal forest fragment of 36.5 ha in the urban area of Jataí, Goiás. We performed the sampling with 30 sand track plots (1 x 1 m). We analyzed the relative record frequency and built a collector's curve to demonstrate the sampling effort. With a total effort of 600 track plots × days, we recorded twelve species of mammals with our tracks sampling method, from which only the wild mammals were included in the analyzes (11 species). The estimated species richness reached 13 species (SD (Standard Deviation) = ±1, CI (Confidence Interval) = ±2 (11 – 15 species). The species with the highest relative record frequency was Didelphis albiventris and the species with the lowest was Tamandua tetradactyla. The fragment size must be a limiting factor to the richness and to the occurrence of species, as it may not be sufficient to allow the persistence of a population or an individual. Disturbances that originated from houses, like domestic animals and movement of people, also contributed to the removal and extinction of species. To conserve the species in the fragment, we suggest the prevention of entrance of people and of domestic animals. We also recommend increased connectivity of the fragment with the landscape external to the urban area in order to allow the movement of the currently present species.

Antipredator strategies of house finches in towns

Valcarcel, A., & Fernández-Juricic, E. (2009). Antipredator strategies of house finches: are urban habitats safe spots from predators even when humans are around?. Behavioral Ecology and Sociobiology, 63(5), 673-685.

Urbanization decreases species diversity, but it increases the abundance of certain species with high tolerance to human activities. The safe-habitat hypothesis explains this pattern through a decrease in the abundance of native predators, which reduces predation risk in urban habitats. However, this hypothesis does not consider the potential negative effects of human-associated disturbance (e.g., pedestrians, dogs, cats). Our goal was to assess the degree of perceived predation risk in house finches (Carpodacus mexicanus) through field studies and semi-natural experiments in areas with different levels of urbanization using multiple indicators of risk (flock size, flight initiation distance, vigilance, and foraging behavior). Field studies showed that house finches in more urbanized habitats had a greater tendency to flock with an increase in population density and flushed at larger distances than in less urbanized habitats. In the semi-natural experiment, we found that individuals spent a greater proportion of time in the refuge patch and increased the instantaneous pecking rate in the more urbanized habitat with pedestrians probably to compensate for the lower amount of foraging time. Vigilance parameters were influenced in different ways depending on habitat type and distance to flock mates. Our results suggest that house finches may perceive highly urbanized habitats as more dangerous, despite the lower number of native predators. This could be due to the presence of human activities, which could increase risk or modify the ability to detect predators. House finches seem to adapt to the urban environment through different behavioral strategies that minimize risk.

Dog, the most recorded carnivore in Brazilian Atlantic forest

Paschoal, A. M. O., Massara, R. L., Santos, J. L., & Chiarello, A. G. (2012). Is the domestic dog becoming an abundant species in the Atlantic forest? A study case in southeastern Brazil. Mammalia, 76(1), 67-76.

The Brazilian Atlantic forest has been reduced to a small fraction of its original area, with most remaining fragments being small and surrounded by anthropogenic matrices. This degree of disturbance, together with the increasing sprawl of cities towards the rural zone, greatly facilitates the entrance of domestic animals into these remnants. We used camera traps to compare the abundances of the domestic dog with a similarly sized native carnivore, the ocelot, in a 957-ha reserve of the Brazilian Atlantic forest in a landscape largely composed by pastures and agriculture. The dog was the most recorded species among all 17 mammal species “captured” by the cameras. Dog abundance (32–38 dogs) and density (0.812–1.813 dogs/km²) were significantly higher than that of the ocelot (n=2 ocelots; density=0.158–0.347 ocelots/km²). Although our result is restricted to a single study site, it is supported by an increasing number of recent studies, which have detected dogs inside other Atlantic forest reserves. Our study suggests, therefore, that this invasion might be more widespread than generally thought. The presence of the domestic dog is a threat to native fauna and constitutes an important edge effect of human presence at the rural zone.

Dog as a disturbance agent

Holderness-Roddam, B (2011) The effects of domestic dogs (Canis familiaris) as a disturbance agent on the natural environment. Research Master thesis, University of Tasmania.

This study assesses the impact of domestic dogs on the natural environment. The principal issue investigated is that of disturbance and the consequences for native wildlife, particularly vertebrate species. In addition to the catastrophic effects of killing, maiming and orphaning of wildlife; disturbance can contribute to energetic loss through premature flight or reduced feed intake and reproductive disruption due to nest disturbance. Dogs have been implicated in disease transmission to native wildlife; with faecal contamination of waterways having potential negative affects for marine mammal health. Hybridisation with other canid species is also an issue of concern, as is expropriation of land for the production of food for pet dogs.

The study commences with an overview of ecological disturbance. The literature review then assesses the role of domestic dogs in ecological disturbance, public attitudes towards compliance with dog management legislation and the remediation and mitigation of disturbance by dogs. 

Data obtained from the Resource Management and Conservation section of the Tasmanian Department of Department of Primary Industries, Parks, Water and Environment regarding native wildlife presenting for care was analysed in order to determine the principal reported causes of death and injury to native wildlife in Tasmania. These results were then compared with data from the Australian Wildlife Health Centre - Wildlife Hospital at Healesville Sanctuary in Victoria and the data submitted by Tasmanian veterinarians through a three month diary of wildlife presentations recorded by ten practices.
The data is indicative of domestic dogs having a more deleterious effect than domestic cats on native wildlife in Tasmania; particularly in urban and suburban areas and on beaches.

Impact of dogs on gazelle kids

Manor, R., & Saltz, D. (2004). The impact of free-roaming dogs on gazelle kid/female ratio in a fragmented area. Biological Conservation, 119(2), 231-236.

One of the consequences of fragmentation is a combination of increased proximity to human dominated areas and an influx of free-roaming dogs. In fragmented habitats those dogs are expected to have a considerable impact on ungulate populations since conditions are, in effect, similar to alien species on islands.

 We studied the impact of free-roaming dogs (Canis familiaris) on the kid/mother ratio of mountain gazelle (Gazella gazella gazella) in an isolated area heavily disturbed by human activity. We used the kid/female ratio as an index of recruitment in the gazelle populations and evaluated the impacts of dog presence, intensity of human disturbance, and forage and cover availability on this ratio over space and time. Data were collected from direct observations. Overall, kid/female ratio in the area is too low for population growth; a finding that is in agreement with drive counts indicating a consistent decline over the past four years (1998–2001). Our results show that free-roaming dogs were the overwhelming factor affecting kid/female ratio in this area. Gazelles responded positively and quickly to dog culling. Thus, free-roaming dogs appear to be a considerable threat to the gazelle population in the study area. Removal of those dogs on a regular basis is an adequate short-term management protocol for increasing gazelle recruitment rate. However, a permanent solution would require reducing the number of dogs by limiting human waste disposal. These results suggest that, in addition to the loss of habitat and connectivity, free-roaming dogs can be a major threat to native ungulates in human dominated fragmented landscapes.

Dogs in rural Zimbabwe: disease transmission and competition with scavengers

Butler, J. R. A., & Toit, J. T. (2002). Diet of free‐ranging domestic dogs (Canis familiaris) in rural Zimbabwe: implications for wild scavengers on the periphery of wildlife reserves. Animal Conservation, 5(1), 29-37.

Numbers of free-ranging dogs (Canis familiaris) have reached unprecedented levels in Zimbabwean communal lands (agropastoralist rural areas). This study examined the potential competitive interactions between dogs and wild scavengers on the boundary of Gokwe Communal Land (GCL) and the Sengwa Wildlife Research Area (SWRA) in 1995–96. Dietary studies showed that dogs were primarily scavengers of human waste and animal carcasses. Twelve experimental carcasses indicated that dogs were the most successful species in the vertebrate scavenger guild, consuming 60% of available biomass and finding 66.7% of carcasses. Dogs monopolized the supply of domestic animal carrion within GCL, but also consumed wild carrion up to 1 km within the SWRA, and were seen 3 km inside the reserve. Their principal competitors for carcasses were vultures, and to a lesser degree lions (Panthera leo), leopards (P. pardus) and spotted hyaenas (Crocuta crocuta). Dogs outcompete vultures on wildlife reserve boundaries owing to their high densities, nocturnal and diurnal activity, physical dominance and greater tolerance of human disturbance. With a population growth rate of 6.5% per annum the influence of dogs will intensify on the peripheries of reserves, exacerbating their existing threat to wild scavengers. This scenario is probably occurring in many other African countries.

Butler, J. R. A., Du Toit, J. T., & Bingham, J. (2004). Free-ranging domestic dogs (Canis familiaris) as predators and prey in rural Zimbabwe: threats of competition and disease to large wild carnivores. Biological Conservation, 115(3), 369-378.

Domestic dogs (Canis familiaris) arrived in Zimbabwe ca. 1000 years ago. Numbers of free-ranging dogs have reached unprecedented levels in communal lands (agro-pastoralist rural areas), and interact with large wild carnivores along boundaries with wildlife reserves as predators and prey. This study examined a population of 236 dogs in a 33-km² section of Gokwe Communal Land (GCL) bordering the Sengwa Wildlife Research Area (SWRA) in north-western Zimbabwe in 1995–1996. Dogs were found up to 6 km within the SWRA, and were the most common carnivore on the GCL–SWRA boundary. Observations of 16 radio-collared dogs showed that they were inefficient predators. Only 20 kills were recorded amongst the remaining dog population, of which three were wild ungulates. Dogs were unsuccessful predators due to their small group size (mean 1.7) and body mass (mean 14.7 kg), and the abundance of alternative food. It is therefore unlikely that they compete with large carnivores for wild prey. However, leopards (Panthera pardus), lions (P. leo) and spotted hyaenas (Crocuta crocuta) preyed on dogs in GCL, removing ⩾6% of the dog population in 1993. Such predation provides ideal circumstances for disease transmission. Canid disease was prevalent in the study area; including rabies and probably distemper. The risk of infection is greatest during the dry season (May–October), when peaks in rates of disease, carnivore incursions into GCL, and predation on dogs coincided. The role of jackals (Canis adustus and Canis mesomelas) and spotted hyaena predation of dogs is discussed in relation to disease epidemics within wildlife reserves. With a dog population growth rate of 6.5% per annum, and the prevalence of canid diseases, the conservation threat posed by dogs is escalating on communal land–wildlife reserve boundaries in Zimbabwe. Measures to control dog numbers and improve vaccination coverage of dogs are discussed.

Leash regulations lack of impact on small vertebrates

Forrest, A. & C.C. St. Clair. 2006. Effects of dog leash laws and habitat type on avian and small mammal communities in urban parks. Urban Ecosystems, 9:51–66

Remnant natural areas within urban settings can act as important refuges for wildlife, substantially increasing local biodiversity. However, habitat suitability for these species is potentially affected by human recreational activities including the presence of free-running dogs. To compare the diversity and abundance of songbird and small mammal communities between areas with bylaws that require, or do not require, dogs to be leashed, point counts and live-trapping surveys were conducted in three habitat types (deciduous, coniferous, and meadow) in the river valley parks of Edmonton, Alberta. Among birds, there was no difference between areas with different leashing bylaws in species diversity for any of the three habitat types. Similarly, there was no difference in bird diversity for a subset of species that were plausibly breeding at these sites. However, higher bird diversity was recorded in deciduous and coniferous sites than in meadow sites, regardless of leash designation, probably as a function of the horticultural practice of mowing meadows. Among both birds and small mammals, there was no difference in the abundance of individuals as a function of leashing bylaws. Our results suggest that off-leash dogs have no effect on the diversity or abundance of birds and small mammals in urban parks, but it is also possible that other factors, such as leash law compliance, reduced or obscured the effects of off-leash dogs in this study.