AboutZoos, Since 2008


Domes­tic dogs almost as dam­ag­ing as cats to endan­gered wildlife

pub­lished 07 May 2017 | mod­i­fied 07 May 2017

dog with hareAuthors: Tim Doherty, Deakin Uni­ver­sity; Aaron J. Wirs­ing, Uni­ver­sity of Wash­ing­ton; Chris Dick­man, Uni­ver­sity of Syd­ney; Dale Nimmo, Charles Sturt Uni­ver­sity; Euan Ritchie, Deakin Uni­ver­sity, and Thomas New­some, Deakin Uni­ver­sity

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. Domes­tic dogs include feral and free-​ranging ani­mals (such as vil­lage and camp dogs), as well as those that are owned by and com­pletely depen­dent on humans (pet dogs).

The lat­est research of an inter­na­tional team of sci­en­tists reveals that the eco­log­i­cal “paw­print” of domes­tic dogs is much greater than pre­vi­ously realised.

Using the IUCN Red List of Threat­ened Species, they counted how many species are neg­a­tively affected by dogs, assessed the preva­lence of dif­fer­ent types of impacts, and iden­ti­fied regions with the great­est num­ber of affected species.

Dogs are third-​most-​damaging mam­mal
They found that dogs are impli­cated in the extinc­tion of at least 11 species, includ­ing the Hawai­ian Rail and the Tonga Ground Skink. Dogs are also a known or poten­tial threat to 188 threat­ened species world­wide: 96 mam­mal, 78 bird, 22 rep­tile and three amphib­ian species. This includes 30 crit­i­cally endan­gered species, two of which are classed as “pos­si­bly extinct”.

These num­bers place dogs in the num­ber three spot after cats and rodents as the world’s most dam­ag­ing inva­sive mam­malian preda­tors.

Even though dogs have an almost global dis­tri­b­u­tion, the threat­ened species they are known to affect are con­cen­trated in cer­tain parts of the globe. South-​East Asia, South Amer­ica, Cen­tral Amer­ica and the Caribbean each con­tain 28 to 30 threat­ened species impacted by dogs. Other hotspots include Aus­tralia, Micro/​Mela/​Polynesia and the remain­der of Asia.

dogs geographical impactRegional con­cen­tra­tions of threat­ened species neg­a­tively impacted by domes­tic dogs (Canis famil­iaris). Num­ber of species is given in paren­the­ses for some small island regions.
The global impacts of domes­tic dogs on threat­ened vertebrates

Lethal and non-​lethal impacts
Pre­da­tion was the most com­monly reported impact of dogs on wildlife. The typ­i­cally omniv­o­rous diet of dogs means they have strong poten­tial to affect a diver­sity of species. For instance, dogs killed at least 19 endan­gered Kagu (a ground-​dwelling bird) in New Cale­do­nia in 14 weeks. Threat­ened species with small pop­u­la­tion sizes are par­tic­u­larly vul­ner­a­ble to such intense bouts of predation.

dog impact on wildlifePer­cent­age of extinct or threat­ened ver­te­brate species that are, or were, affected by dif­fer­ent types of dog impact.
The global impacts of domes­tic dogs on threat­ened vertebrates

Aside from sim­ply killing ani­mals, dogs can harm wildlife in other ways, such as by spread­ing dis­ease, inter­breed­ing with other canids, com­pet­ing for resources such as food or shel­ter, and caus­ing dis­tur­bances by chas­ing or harass­ment. For exam­ple, con­tact with domes­tic dogs increases dis­ease risk for endan­gered African Wild Dogs in Kenya.

Part of the prob­lem is that when wild ani­mals per­ceive dogs as a threat, they may change their behav­iour to avoid them. One study near Syd­ney found that dog walk­ing in park­lands and national parks reduced the abun­dance and species rich­ness of birds, even when dogs were restrained on leads.

None of the Red List assess­ments men­tioned such indi­rect risk effects, which sug­gests that their fre­quency is likely to be much higher than reported.

Friend and foe
Despite their wide­spread and some­times severe impacts on bio­di­ver­sity, dogs can also ben­e­fit some species and ecosys­tems.

For exam­ple, in Aus­tralia, the closely related dingo (Canis lupus dingo) can sup­press pop­u­la­tions of intro­duced preda­tors such as red foxes (Vulpes vulpes), and in doing so can ben­e­fit smaller native prey. It is pos­si­ble that domes­tic dogs could per­form sim­i­lar eco­log­i­cal roles in some situations.

In some regions, dogs and their keen noses have been trained to help sci­en­tists find threat­ened species such as Tiger Quolls. Else­where they are help­ing to flush out and con­trol feral cats.

An emerg­ing and excit­ing con­ser­va­tion role for dogs is their grow­ing use as “guardian ani­mals” for wildlife, with the remark­able story of Odd­ball being the most well known.

Man­ag­ing the prob­lem
Dogs not only inter­act with wildlife, but can also attack and spread dis­ease to humans, live­stock and other domes­tic ani­mals. As such, man­ag­ing the prob­lem requires look­ing at eco­log­i­cal, cul­tural and social perspectives.

Some of the regions with high num­bers of species threat­ened by dogs are also hotspots for urban­i­sa­tion and road build­ing, which make it eas­ier for dogs to access the habi­tats of threat­ened species. Urban devel­op­ment increases food waste, which feeds higher num­bers of dogs. As dogs expand into new areas, the num­ber of species they impact is likely to grow.

We can pro­tect wildlife by inte­grat­ing human health and ani­mal wel­fare objec­tives into dog man­age­ment. Vac­ci­na­tion and desex­ing cam­paigns can reduce dis­ease risk and over­pop­u­la­tion prob­lems. We should also focus on respon­si­ble dog own­er­ship, remov­ing dogs with­out own­ers, and reduc­ing access to food waste.

Given the close rela­tion­ship between humans and dogs, com­mu­nity engage­ment should form the basis of any man­age­ment pro­gram. More research is needed to get a bet­ter pic­ture of the scale of the prob­lem, and of how dogs inter­act with other threats such as habi­tat loss. Such actions are crit­i­cally impor­tant for ensur­ing the con­ser­va­tion of wildlife threat­ened by dogs around the world.

The Conversation

This arti­cle was co-​authored by Dr Al Glen from Land­care Research, New Zealand and Dr Abi Vanak from the Ashoka Trust for Research in Ecol­ogy and the Envi­ron­ment, India. These insti­tu­tions had no role in the design or fund­ing of the research.

This arti­cle was orig­i­nally pub­lished on The Con­ver­sa­tion.

(Source: THE CON­VER­SA­TION The bark side: domes­tic dogs threaten endan­gered species world­wide, 01.05.2017)

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