Month: October 2020

Hi everyone! Previously I shared my observations of Free-ranging domestic dog (FRDDs) packs. Not only are the pack gaining more dog members, I realised that the FRDD packs are venturing into residential areas more frequently as well. These occurrences started happening after the establishment of new residential flats in Tampines.

This photo was from 7 November 2018, which coincides with the construction period of Build-To-Order flats in Tampines. I wonder if this observation has got to do with the increasing land use for residential areas. If so, are they venturing to new territories they have yet to explore?

Indeed, there were reports by some park visitors of the stray dog packs in Tampines nature parks under the National Parks Board. I suspect there would be an increased probability of dog-wildlife conflict in the parks, considering there are stray dog-cat conflicts.

    “Fatal attack of a cat by stray dogs” Photo by Rachel Ong

 

My suspicion is confirmed by the predation on primates by FRDDs in Bukit Timah Reserve (Riley et al., 2015). It was observed that a pack of 3FRDDs killed a juvenile Long-tailed macaque (Macaca fascicularis). Though Singapore’s Animal Veterinary Authority has culled 360 macaques in 2013 in response to 920 complaints from residents living near the reserve borders or park visitors, of “monkey nuisance”. The Macaca fascicularis is considered “Vulnerable” under the IUCN Red List, meaning they face high extinction risk in the wild.

The unfortunate attack happened on a man-made bicycle path within the reserve. Well, being on an anthropogenic landscape has decreased the macaque’s probability of survival since it was not on a tree where the dogs cannot reach, nor did it had time to respond and climb onto trees. Hence, one seemingly harmless man-made path raised the susceptibility of the prey to FRDD attacks. This occurrence reflects my sentiment on how anthropogenic factors are tied to the increasing impacts of FRDDs.

I wondered if humans have unknowingly paved the way for FRDDs in becoming effective predators of wildlife species, with our modifications to the environment?  Let us investigate if Australia has magnified impacts of FRDD due to human-modified environments.

The study by Taylor et al. (2018) addresses how the environmental impacts by FRDD could potentially be amplified by urbanisation. The data collected from Australia Zoo Wildlife Hospital and Wildlife Rehabilitation Centre showed that dog attacks were the second most common reason for wildlife to be admitted for medical treatment, with car strikes being the first. It was highlighted that Koala bears (Phascolarctos cinereus), classified as vulnerable under IUCN Red List, were attacked by FRDDs in urbanised areas at bridges and telegraph poles. This signifies how human-modified environments not only cause habitat loss and habitat fragmentation, but it could also facilitate hunting of wildlife by dogs as well.

This highlights the need for wildlife conservation methods to be reconsidered in the process of urban expansion, with the FRDDs in mind.

I’ll side-track here: Do you think the culling of Macaques by Singapore is appropriate or just a knee-jerk reaction to complaints? The vulnerability of the Macaca fascicularis species reflects the intra-specific taxa assessment of the subspecies Macaca fascicularis ssp. philippensis in Philippines, threatened by sport hunting, research purposes and consumption by humans. On the other hand, the macaque is considered invasive under the Global Invasive Species Database (GISD), managed by IUCN, due to their impacts on native biodiversity. Isn’t Singapore doing biodiversity a favour? I’ll discuss more about environmental ethics in decision making related to FRDD in my next post!

 

References:
Eudey, A., Kumar, A., Singh, M. & Boonratana, R. 2020. Macaca fascicularis. The IUCN Red List of Threatened Species 2020: e.T12551A17949449. https://dx.doi.org/10.2305/IUCN.UK.2020-2.RLTS.T12551A17949449.en. Downloaded on 30 October 2020.

Riley Koenig, Crystal & Koenig, Bryan & Gumert, Michael. (2015). Observation of a fatal dog attack on a juvenile long-tailed macaque in a human-modified environment in Singapore. Nature in Singapore. 8. 57-63.

Taylor-Brown A, Booth R, Gillett A, Mealy E, Ogbourne SM, et al. (2019) The impact of human activities on Australian wildlife. PLOS ONE 14(1): e0206958. https://doi.org/10.1371/journal.pone.0206958

Woinarski, J. & Burbidge, A.A. 2020. Phascolarctos cinereus (amended version of 2016 assessment). The IUCN Red List of Threatened Species 2020: e.T16892A166496779. https://dx.doi.org/10.2305/IUCN.UK.2020-1.RLTS.T16892A166496779.en. Downloaded on 30 October 2020.

Hi everyone!

This week I want to share with you my trip to the coastal farms. Let me show you this video on Animal Veterinary Service’s rabies vaccination exercise for dogs, where Rabies is a zoonotic disease that can spread from animals to humans and other animals.

Vaccination for dogs on floating farms. 

As we traveled to various coastal farms, I pondered why Singapore is worried about the dogs that are offshore and on seemingly isolated coastal farms. I spoke to the veterinarians and found out that dogs are mostly stray dogs and utilised as guard dogs. As mentioned by Dr. Fernandez, the dogs are mostly unsupervised and can get Rabies by swimming to watercraft from other countries (Goh, 2019).  Turns out, dogs can swim very well!

Meaning to say, free-ranging domestic dogs (FRDD) can be the perfect recipe for a disastrous spread of rabies, if not managed well. I can imagine how hard it is to manage and monitor the spread of diseases in countries that has a much greater FRDD population than Singapore.

Other than the fact that rabies extremely fatal to humans, its zoonotic potential extends to wildlife as well. Unfortunately, the endangered species of Ethiopian Wolf (Canis simensis) is not spared from the disease. In 2004 on the Bale Mountains of Ethiopia, there was an outbreak of Rabies resulting in 38 deaths of Ethiopian Wolves. The number may seem small, but their population of 300 is not huge to begin with (Randall, 2005).

“Ethiopian Wolf with rodent prey” by Magnus.

And their cause of death?

The FRDDs!

The period of outbreak coincides with the appearance FRDDs with signs of rabies around their habitat. Though how it transmits from FRDD to the dogs were not discovered, Rabies mainly transmit through bites, but can also spread through open wounds, eyes, and lips via infectious saliva (Rabies, 2020).

So what makes them “Endangered” under the IUCN Red List? The wolves are threatened by habitat loss due to agriculture. With only 197 mature Ethiopian wolves left to produce offspring, it is time to question farming methods like pastoralist grazing, where farmers move their livestock to a new land when the previous land is overgrazed. This farming method not only takes up space, but it also wipes out the habitat of the wolves’ prey, the Giant Mole Rat (Tachyoryctes macrocephalus), which is an endangered species under the IUCN Red List.  Let’s not forget the angry farmers who killed the wolves for murdering their cattle (or were the true culprits the dogs?).

Since the Ethiopian wolves are keystone species, they have direct influences on their food webs. The declining numbers would highly impact the ecosystem and cause a collapse (Keystone Species, n.d.). Moreover, changes to ecosystem cues the chance for FRDDs or any other invasive species to invade it.

Though not intentionally, the FRDDs are undeniably carriers or hotbed for pathogens. Their presence itself will always pose a threat to the whole ecosystem via transmitting diseases to wildlife.

To add on to the never-ending list of problems, there are other diseases like Canine Distemper Virus and others here that FRDDs can be transmitted to wildlife as well. Though there are rabies vaccination programs for FRDDs, in 2008, another rabies outbreak caused 75% of the Ethiopian wolves to die (Reproductive Physiology of Ethiopian wolves, n.d.).

How do we then protect wildlife species?

Reference:

Goh, T., 2019. Anti-Rabies Operation On Dogs On Coastal Farms Keeps Singapore Safe From Virus. [online] The Straits Times. Available at: <https://www.straitstimes.com/singapore/health/anti-rabies-operation-on-dogs-on-coastal-farms-keeps-singapore-safe-from-virus> [Accessed 9 October 2020].

National Geographic Society. n.d. Keystone Species. [online] Available at: <https://www.nationalgeographic.org/encyclopedia/keystone-species/> [Accessed 9 October 2020].

Randall, Dashaun & Williams, Stuart & Kuzmin, Ivan & Rupprecht, Charles & Tallents, Lucy & Tefera Ashenafi, Zelealem & Argaw, Kifle & Shiferaw, Fekadu & Knobel, Darryn & Sillero, Claudio & Laurenson, M. (2005). Rabies in Endangered Ethiopian Wolves. Emerging infectious diseases. 10. 2214-7. 10.3201/eid1012.040080.

World Health Organisation. 2020. Rabies. [online] Available at: <https://www.who.int/news-room/fact-sheets/detail/rabies> [Accessed 9 October 2020].

Hi everyone! This week, I want to share an exciting observation I made on the Free-ranging domestic dogs (FRDDs), a.k.a street dogs.

Out of curiosity and love for dogs, I always lookout FRDDs in the field near Tampines IKEA. Nowadays, I see more FRDDs roaming in packs, and the packs are getting bigger! Previously, it was more common for me to spot them in solitary or pairs. And my recent observation? A pack of 8 stray dogs!

Solitary dog in 2016.

FRDD dog pack from Tampines field in 2020

 

I realised that the dog packs appeared after the new establishments of HDB flats in Tampines. I guess that the urbanization involving the use of land space has shrunk the usual natural spaces these FRDDs can roam, creating more chances to encounter one another and have greater chances to form packs.

This made me wonder, knowing that FRDDs know how to form packs, this surely would have more impacts on the environment. When I was young, I was always in denial when my father told me about how the village dogs (unowned FRDD) would team up to hunt for birds. I mean, aren’t they fed enough? Well, turns out I was wrong. According to Bonanni & Cafazzo (2014), FRDDs prefer to hunt cooperatively in a pack than solitarily, especially in places with suitable prey and fewer food resources by humans. I was curious about what types of prey FRDDs would predate on and how this predatory behaviour contributes to loss of biodiversity, so I did some research to find out more!

In India, FRDD packs compete with the Indian Wolf (Canis lupus pallipes) for the Blackbuck (Antilope cervicapra). On top of that, Jhala & Giles (1991) reported that the FRDDs killed the Antilope fawns. This worries me as they even attack young fawns, would there be enough surviving offspring to maintain their species? Moreover, the Indian Wolf species are listed as “Endangered” under the Wildlife Protection Act, with an estimate of only 3000 of them left. The competition with FRDD is an energetically costly behaviour, which I feel can affect the wolf’s daily activities and behaviour (Too tired to mate perhaps?).

Even though Blackbucks are classified “Least concerned” under the International Union for Conservation of Nature (IUCN) Red List of threatened species, I do feel that the predation of any wildlife species by the FRDDs can pose a significant threat to the environment.

Let us look at this food web I made to better illustrate the significance of the FRDD predation and how interconnected food chains are in the forest ecosystem of India.

From this, we can see that due to the competition with FRDD for Blackbuck, the Indian wolves may resort to consuming more of other prey within their diet, for example, the Indian Hares (Lepus nigricollis). Unfortunately, the Indian Hares are also part of the food chain for the Indian leopard, which is classified as “Vulnerable” under the IUCN Red List, meaning the leopards face high extinction rates in the wild without interventions. The Indian leopard would tend to consume other prey within its diet, which are part of other food chains. Ultimately, this affects the entire ecosystem, where a change in the population numbers in one trophic level can cause a cascade effect, a chain of events that disrupt a balanced ecosystem of the environment, leading to loss of biodiversity of wildlife.

For my next post, let’s see how free-ranging domestic cats impact the environment!

Paws out!

References:

Bonanni, R and Cafazzo, S. (2014). The Social Organisation of a Population of Free-Ranging Dogs in a Suburban Area of Rome: A Reassessment of the Effects of Domestication on Dogs’ Behaviour. 10.1016/B978-0-12-407818-5.00003-6.

Hughes, J. and Macdonald, D. (2013). A review of the interactions between free-roaming domestic dogs and wildlife. Biological Conservation, 157, pp.341-351.

Jhala, Y. and Giles, R. (1993). The status and conservation of the wolf in Gujarat and Rajasthan, India. Biological Conservation, 63(3), p.276.