Early introgression of dog genes during re-expansion of wolf in Italy

Randi, E., Hulva, P., Fabbri, E., Galaverni, M., Galov, A., Kusak, J., Bigi, D., Černá Bolfíková, B., Smetanová, M. & Caniglia, R. (2014). Multilocus Detection of Wolf x Dog Hybridization in Italy, and Guidelines for Marker Selection. PLOS ONE, 9(1), e86409.

Hybridization and introgression can impact the evolution of natural populations. Several wild canid species hybridize in nature, sometimes originating new taxa. However, hybridization with free-ranging dogs is threatening the genetic integrity of grey wolf populations (Canis lupus), or even the survival of endangered species (e.g., the Ethiopian wolf C. simensis). Efficient molecular tools to assess hybridization rates are essential in wolf conservation strategies. We evaluated the power of biparental and uniparental markers (39 autosomal and 4 Y-linked microsatellites, a melanistic deletion at the β-defensin CBD103 gene, the hypervariable domain of the mtDNA control-region) to identify the multilocus admixture patterns in wolf x dog hybrids. We used empirical data from 2 hybrid groups with different histories: 30 presumptive natural hybrids from Italy and 73 Czechoslovakian wolfdogs of known hybrid origin, as well as simulated data. We assessed the efficiency of various marker combinations and reference samples in admixture analyses using 69 dogs of different breeds and 99 wolves from Italy, Balkans and Carpathian Mountains. Results confirmed the occurrence of hybrids in Italy, some of them showing anomalous phenotypic traits and exogenous mtDNA or Y-chromosome introgression. Hybridization was mostly attributable to village dogs and not strictly patrilineal. The melanistic β-defensin deletion was found only in Italian dogs and in putative hybrids. The 24 most divergent microsatellites (largest wolf-dog F_ST values) were equally or more informative than the entire panel of 39 loci. A smaller panel of 12 microsatellites increased risks to identify false admixed individuals. The frequency of F1 and F2 was lower than backcrosses or introgressed individuals, suggesting hybridization already occurred some generations in the past, during early phases of wolf expansion from their historical core areas. Empirical and simulated data indicated the identification of the past generation backcrosses is always uncertain, and a larger number of ancestry-informative markers is needed.


Read more about canine hybidisation and gene introgression

Dog distemper affecting wolfs

Di Sabatino D, Lorusso A, Di Francesco CE, Gentile L, Di Pirro V,  Bellacicco, A.L., Giovannini, A., Di Francesco, G., Marruchella, G., Marsilio, F. & Savini, G. (2014) Arctic Lineage-Canine Distemper Virus as a Cause of Death in Apennine Wolves (Canis lupus) in Italy. PLoS ONE 9(1): e82356. doi:10.1371/journal.pone.0082356

Canine distemper virus (CDV) infection is a primary threat affecting a wide number of carnivore species, including wild animals. In January 2013, two carcasses of Apennine wolves (Canis lupus) were collected in Ortona dei Marsi (L'Aquila province, Italy) by the local Veterinary Services. CDV was immediately identified either by RT-PCR or immunohistochemistry in lung and central nervous tissue samples. At the same time, severe clinical signs consistent with CDV infection were identified and taped (Videos S1–S3) from three wolves rescued in the areas surrounding the National Parks of the Abruzzi region by the Veterinary Services. The samples collected from these symptomatic animals also turned out CDV positive by RT-PCR. So far, 30 carcasses of wolves were screened and CDV was detected in 20 of them. The sequencing of the haemagglutinin gene and subsequent phylogenetic analysis demonstrated that the identified virus belonged to the CDV Arctic lineage. Strains belonging to this lineage are known to circulate in Italy and in Eastern Europe amongst domestic dogs. To the best of our knowledge this is the first report of CDV Arctic lineage epidemics in the wild population in Europe.

Farm dogs aroung protected areas: problem or solution?

Sepúlveda, M. A., Singer, R. S., Silva-Rodríguez, E., Stowhas, P., & Pelican, K. (2014). Domestic Dogs in Rural Communities around Protected Areas: Conservation Problem or Conflict Solution?. PLOS ONE, 9(1), e86152.

Although domestic dogs play many important roles in rural households, they can also be an important threat to the conservation of wild vertebrates due to predation, competition and transmission of infectious diseases. An increasing number of studies have addressed the impact of dogs on wildlife but have tended to ignore the motivations and attitudes of the humans who keep these dogs and how the function of dogs might influence dog-wildlife interactions. To determine whether the function of domestic dogs in rural communities influences their interactions with wildlife, we conducted surveys in rural areas surrounding protected lands in the Valdivian Temperate Forests of Chile. Sixty percent of farm animal owners reported the use of dogs as one of the primary means of protecting livestock from predators. The probability of dog–wild carnivore interactions was significantly associated with the raising of poultry. In contrast, dog–wild prey interactions were not associated with livestock presence but had a significant association with poor quality diet as observed in previous studies. Dog owners reported that they actively encouraged the dogs to chase off predators, accounting for 25–75% of the dog–wild carnivore interactions observed, depending on the predator species. Humans controlled the dog population by killing pups and unwanted individuals resulting in few additions to the dog population through breeding; the importation of predominantly male dogs from urban areas resulted in a sex ratios highly dominated by males. These results indicate that dog interactions with wildlife are related to the role of the dog in the household and are directly influenced by their owners. To avoid conflict with local communities in conservation areas, it is important to develop strategies for managing dogs that balance conservation needs with the roles that dogs play in these rural households.

Ascension frigatebird - the return continues

... For over a century, these seabirds have been confined to breeding on the small outlying islet, Boatswainbird Island, after taking refuge there from the feral cat population on Ascension’s mainland. Cats were introduced onto the island in the early 19th Century to control introduced rats and mice, but instead made a significant dent on the seabird populations. The RSPB initiated a project in 2002, supported by funding from the Foreign and Commonwealth Office, to remove feral cats from the island that proved successful, with Ascension being declared feral cat free in 2006. The seabirds began to return to nesting on the mainland immediately, starting with the masked boobies, but it wasn’t until 2012 that the island’s most iconic seabird began its return.

From RSPB 

Bird assemblage and cat density

Victoria Sims, Karl L. Evans, Stuart E. Newson, Jamie A. Tratalos and Kevin J. Gaston. 2008.  Avian assemblage structure and domestic cat densities in urban environments. Diversity and Distributions, 14, 387–399

While there is intense debate regarding the impact of domestic cat populations on wildlife, its resolution is hindered by the lack of quite basic information. Domestic cats are generalist and obligate predators that receive supplementary food, and their population density reflects that of humans more than the density of their prey. In such a predator–prey system there is the potential for cat populations to have negative impacts on avian assemblages, which may be indicated by negative correlations between cat density and avian species richness and density. Here we report on the nature of such correlations across urban areas in Britain both for groups of species classified regarding their vulnerability to cat predation and individual species.
Taking the availability of green space into account, we find negative relationships between cat densities and the number of bird species breeding in urban 1 km × 1 km squares. These relationships are particularly strong among groups of species that are vulnerable to cat predation. We find positive correlations between cat and avian densities; these have low explanatory power and shallow slopes among the species groups that are particularly vulnerable to cat predation. Evidence that the densities of individual species that are vulnerable to cat predation are negatively correlated with cat densities is equivocal, with at least half the species showing no marked pattern, and the remainder exhibiting contrasting patterns. Our results appear not to be confounded by the density of nest-predating corvids (carrion crow, magpie, and jay), as the density of these species was not strongly negatively correlated with avian species richness or density. The general lack of marked negative correlations between cat and avian densities at our focal spatial scale may be a consequence of consistently high cat densities in our study areas (minimum density is 132 cats per square kilometre), and thus uniformly high impacts of cat populations on urban avian assemblages.

Cats on islands: impacts other than predation

Medina, F. M., Bonnaud, E., Vidal, E., & Nogales, M. (2014). Underlying impacts of invasive cats on islands: not only a question of predation. Biodiversity and Conservation, 23 (2): 327-342.

The domestic cat has been introduced on most islands worldwide, where it has established feral populations and is currently known to be one of the worst invasive mammalian predators. Predation is the strongest deleterious effect of cats on wildlife, inducing a direct negative impact on population size and dynamics, breeding success and changes in species assemblages. Direct predation is not the only damaging impact on native wildlife, since cats can be responsible for other poorly-documented underlying ecological impacts, like competition, hybridization, disease transmission, ecological process alteration, and behavioral change. Here, we pinpoint relevant examples of these ecological impacts, by searching for accurate data from published literature. We used electronic databases covering most of the world islands where the effects of cats were documented. Knowledge of these impacts can be of great importance to preserve insular ecosystem functions and persistence of endangered native species. We emphasize that direct predation processes should not be the only factor considered in the management of invasive cats on islands.

Impact of introduced cats on island biodiversity

Hervías, S., Oppel, S., Medina, F. M., Pipa, T., Díez, A., Ramos, J. A., Ruiz de Ybáñez, R. & Nogales, M. (2014). Assessing the impact of introduced cats on island biodiversity by combining dietary and movement analysis. Journal of Zoology, 292: 39-47

Populations of feral (not owned by humans) and domestic cats Felis catus coexist in most inhabited islands, and they have similar impacts on native species. Feral cats are generally believed to vary their diet according to prey availability; however, no previous studies of diet have tested this hypothesis on insular ecosystems with a limited range of available prey. Because domestic cats kill prey independently of hunger, the spatial extent of their impact on wildlife will be influenced by home-range size. In this study, we combined dietary information with cat movements to assess the impacts of feral and domestic cats on island biodiversity. We quantified the diet of cats from scat samples collected across one year and tested whether diet varies by season. The abundance of main prey categories was also estimated to document seasonal variation in prey availability for cats. Finally, we tracked domestic cats by global positioning system units in all four seasons to examine whether home-range patterns varied seasonally. The diet of cats constituted three prey groups (rodents, birds and invertebrates), and the seasonal variation in consumption of each taxon matched the seasonal variation in prey availability, thus supporting the generalist behaviour of cats on oceanic islands. Roaming behaviour varied among individuals and across seasons, but could not be explained by availability of prey. Unconfined cats had larger home-ranges than confined cats, but most domestic cats strayed <1 km from home. Thus, confinement of domestic cats might reduce the spatial extent of cat impact on native prey populations on oceanic islands.

Dispersal partner of domestic cats

Devillard, S., Say, L., & Pontier, D. (2003). Dispersal pattern of domestic cats (Felis catus) in a promiscuous urban population: do females disperse or die?.Journal of animal ecology, 72(2), 203-211.

1. The domestic feral cat (Felis catus L.) is a good model for studying intraspecific variability of dispersal patterns in mammals because cats live under a large diversity of socio-ecological conditions. We analysed both the natal and breeding dispersal patterns of domestic cats in a promiscuous urban population and tested whether or not it differed from the male-biased natal dispersal pattern observed for polygynous rural populations.
2. During an 8-year study we recorded the exact date of in situ death for 148 marked cats and the exact date of disappearance from the population for 99 other cats. Because undiscovered deaths might over-estimate dispersal probabilities when considering only disappearance probabilities, we made an novel application of multistrata capture–recapture methods in order to disentangle dispersal from true mortality.
3. We showed that mature females dispersed, both before and after their first reproduction, at 1 and 2 years old. Contrary to females, no dispersal seemed to occur in males. Before sexual maturity, females that disappeared at 1 and 2 years old were in worse body condition than females that stayed in the population area after 2 years old. However, they did not reproduce less successfully before their disappearance than females that died later in the population area.
4. The female-biased and low natal dispersal pattern in this population was atypical compared to other promiscuous/polygynous mammals and differed from that observed in rural polygynous populations of domestic cat. Neither local mate competition nor inbreeding avoidance appeared to be sufficient pressures to counterbalance ecological constraints on dispersal in an urban environment. However, local resource competition for den sites between potential matriarchies could lead to the breeding dispersal of less competitive females.

Early cat taming in Egypt

Linseele, V., Van Neer, W., & Hendrickx, S. (2007). Evidence for early cat taming in Egypt. Journal of Archaeological Science, 34(12), 2081-2090.

The remains are described of a young small felid found in a Predynastic burial at Hierakonpolis, Upper Egypt. Osteometric and zoogeographical arguments indicate that the specimen, dated to around 3700 B.C. on the basis of the associated pottery, belongs to Felis silvestris.

Hunting cat with several bird preys. Tomb of Nebamun 

Thebes, Egypt, 18th dynasty, ca. 1400-1350 BCE.

In the same cemetery several other animal species, both wild and domestic, have been found. The left humerus and right femur of the cat show healed fractures indicating that the animal had been held in captivity for at least 4–6 weeks prior to its burial. We believe that this pathology suggests early cat taming more convincingly than a buried cat recently reported from Neolithic Cyprus (7500 B.C.). Such taming events were probably part of the processes that eventually led to the domestication of Felis silvestris. However, the absence of the cat in Predynastic and Early Dynastic depictions and its rare attestation in the archaeozoological record indicates that domestic status had not yet been attained during those early periods. Other species that were also held in captivity by Ancient Egyptians probably never became domesticated because they had one or more characteristics that prevented it.

Feral cats in a urban conservancy in South Africa

Tennent, J., & Downs, C. T. (2008). Abundance and home ranges of feral cats in an urban conservancy where there is supplemental feeding: a case study from South Africa. African Zoology, 43(2), 218-229.

There is much debate surrounding the impact of feral cats (Felis catus) on wildlife. Conservancies are usually areas where indigenous flora and fauna are protected and aliens excluded or managed. The University of KwaZulu-Natal's Howard College campus (HCC) is an urban conservancy containing feral cats that are presently not managed, and little is known about their ecology and behaviour. Consequently a feral cat population census was conducted, and their home range investigated. Estimates of the overall campus feral cat population numbers ranged between 23.4–40.0 cats/km²  with a minimum of 55 identified as resident. They were not randomly distributed in the study area, with spacing patterns being related to resource availability. Home range area and core distribution of eight radio-collared cats were determined over 13 months. Total home range areas were relatively small, with considerable overlap between them. Home ranges were clustered in areas with permanent feeding stations and these were also within the cats' core ranges. Supplemental food resources appear to have a major influence on numbers, home and core range area, and behavior of cats. It is clear that cat densities grow to high levels with reliable and abundant food supply and only ad hoc sterilization. This has implications for their management in the HCC urban conservancy.

Interbreeding of feral and wild cats in Britain

Hubbard, A.L., S. McOrist, T.W. Jones, R. Boid, R. Scott & N. Easterbee. 1992. Is survival of European wildcats Felis silvestris in Britain threatened by interbreeding with domestic cats? Biological Conservation, 61: 203-208.

The relationship of the domestic cat Felis catus in Britain to the European wildcat Felis silvestris remaining in northern Britain includes a significant overlap of the phenotypic features of introgressive hybrids. The status of wildcats as a separate endangered species requiring protection to remain viable in the wild required analysis of their genetic relationship to domestic cats. Despite the discovery of free-living cats with both phenotypic resemblance to F. silvestris and close genetic similarities to F. catus, as measured by nucleic acid probe analysis, albumin heterogeneity (immunological distance) and isoenzyme analysis, eight of 42 putative wildcats caught in remote areas of northern and western Scotland showed clear differences from F. catus in the genetic analyses used. These eight wildcats had pelages consistent with the wildcat; however, 15 of the remaining cats had pelages containing domestic cat characters and had either one or no wildcat genetic character. The results suggest that some genetically distinct European wildcats remain in Britain, and the efforts to prevent interbreeding with domestic cats may enhance their conservation.

See more on domestic cat introgression in wildcat

Parasite transmision from feral cat to captive neotropical felids

Rendón-Franco, E., Romero-Callejas, E., Villanueva-García, C., Osorio-Sarabia, D., & Muñoz-García, C. I. (2013). Cross transmission of gastrointestinal nematodes between captive neotropical felids and feral cats. Journal of Zoo and Wildlife Medicine, 44(4), 936-940.

Pathogen cross transmission between wildlife and domestic animals represents an extinction risk for wildlife; however, reliable verification is difficult to perform, and in some cases, it is even considered unlikely to be conducted. The aim of this work was to identify cross transmission of helminths between feral cats and captive wild felids at a zoological park in southeastern Mexico. Feces were collected from jaguars (Panthera onca), cougars (Puma concolor), ocelots (Leopardus pardalis), margays (Leopardus wiedii), and jaguarundis (Puma yagouaroundi). A flotation technique and macroscopic sieving were performed on the feces. Additionally, as part of the noxious fauna control program of the park, feral cats were captured and euthanized. To perform parasitologic studies, helminths from these animals were recovered. Toxocara cati and Trichuris campanula were shared by jaguarundis and feral cats. Ancylostoma sp. was found in jaguar and ocelot and Ancylostoma tubaeforme in feral cats. Additionally, during this study, a couple of jaguarundis died with clinical signs of trichuriasis. This is the first report of T. campanula in jaguarundi. Because feral cats roam freely in the park, transmission could occur from these vertebrates to wild felids. This study shows the risk that parasites represent to wild felids; a similar situation could be found in free-living species, especially in fragmented habitats that favor contact with domestic animals.

Invasive mammal eradication on Macquarie Island

Springer, K. 2014. Pest Eradication on Macquarie Island. Australia's State of the Islands Report. Pp. 70-80.

Invasive vertebrate species have been present on Macquarie Island for over 200 years, and have had devastating impacts on flora, fauna and landforms. Weka (Gallirallus australis) were successfully eradicated by 1989 and feral cats (Felis catus) by 2001. Planning for the eradication of ship rats (Rattus rattus), house mice (Mus musculus) and European rabbits (Oryctolagus cuniculus) began in 2004. Funding of AUD$24.7M was secured in 2007 for a multi-year project based on aerial baiting that targeted rabbits and rodents, followed by hunting of any surviving rabbits. Following three years of planning, the first aerial baiting attempt in 2010 was abandoned after two months due to unfavourable weather and shipping delays. The degree of non-target seabird species mortality from the limited baiting in 2010 lead to a renewed examination of non-target mitigation options. Rabbit Haemorrhagic Disease Virus (RHDV) was introduced in February 2011, to reduce the pre-baiting rabbit population and thus minimise non-target mortality amongst scavenging seabirds. Aerial baiting resumed in May 2011 using four AS350 helicopters and a team of 27 people, and was completed by July 2011. No rodents have been detected post-baiting and the estimated rabbit population in excess of 150,000 has been reduced to less than an estimated 30 at the conclusion of baiting. Some rabbits were expected to survive baiting, and the hunting phase commenced in July 2011 using a team of 15 hunters and 12 dogs. By December 2011thirteen rabbits had been accounted for. Hunting efforts are ongoing, and together with a monitoring phase are planned to continue for five years. A minimum of two years monitoring for rabbits will be conducted. Continued effort each year will be based on annual progress reviews. Rodent detection dogs will deploy in 2013 to assist in determining rodent eradication success. After one summer since baiting, vegetation recovery is already evident and increased burrow-nesting seabird activity has also been observed in the first breeding season postbaiting.

Evaluating two census methods

Edwards, G. P., De Preu, N. D., & Crealy, B. S. I. (2000). An evaluation of two methods of assessing feral cat and dingo abundance in central Australia.Wildlife Research, 27(2), 143-149.

We evaluated the efficacy of spotlight surveys and passive track surveys conducted along roads for assessing the relative abundance of feral cats and dingoes in a semi-arid rangeland environment in central Australia. Track surveys were more time-efficient than spotlight surveys and offered higher precision. We cover a range of issues that need to be considered when using track-based surveys to assess population change. We also discuss the merits of other techniques used to monitor the abundance of mammalian carnivores.

Attractans for feral cats

Clapperton, B. K., Eason, C. T., Weston, R. J., Woolhouse, A. D., & Morgan, D. R. (1994). Development and testing of attractants for feral cats, Felis catus L. Wildlife Research, 21(4), 389-399.

As part of a programme to improve feral-cat control and eradication techniques, various odours were tested as candidate lures. They included food odours (fish oils), social odours (urine and its components, anal-sac secretions and commercial wild-animal lures) and plant materials (catnip, matatabi and their essential oils). Pen bioassay experiments used a preference procedure on captive feral and domestic cats to compare the time spent investigating the odours and the number of cats visiting each odour. Field trials at rubbish dumps used scent stations to assess cat activity. Catnip and matatabi were the most promising candidate lures in both the pen bioassay and the field trials. Future directions for lure developments are suggested.