Exploring the Legal Status of Wolf‐Dog Hybrids and Other Dubious Animals: International and EU Law and the Wildlife Conservation Problem of Hybridization with Domestic and Alien Species

• Author: Arie Trouwborst
• Published date: 01 April 2014
• Date: 01 April 2014
• DOI: http://doi.org/10.1111/reel.12052

Exploring the Legal Status of Wolf-Dog Hybrids and

Other Dubious Animals: International and EU Law

and the Wildlife Conservation Problem of

Hybridization with Domestic and Alien Species

Arie Trouwborst

Hybridization with domestic or alien species poses a

threat to many species of wild fauna. However,

hybridization is not explicitly addressed in the provi-

sions of the principal international legal instruments

on nature conservation. This article reviews the rel-

evance, scope and substance of wildlife protection

obligations under the Bern Convention on European

Wildlife and Natural Habitats and the European

Union’s Habitats Directive with respect to this issue.

The problem of wolf-dog hybridization is singled out

as a case study. The article concludes that addressing

hybridization through preventive and mitigation mea-

sures is in conformity with the obligations of States

under the Convention and the Directive, and may

indeed be essential in order to comply with these obli-

gations. In the wolf-dog context, this includes dealing

with feral and stray dogs and captive hybrids, and

removing hybrid animals from the wild. At the same

time, it appears that the national prohibitions on the

killing and capturing of wolves and other strictly pro-

tected species, as prescribed by the Convention and the

Directive, also cover free-ranging wolf-dog hybrids

and similar hybrids living in the wild. This entails that

the removal of such hybrid animals from the wild is

subject to the rules concerning derogations from strict

protection. These rules, however, do not appear to

stand in the way of such removal. The article’s central

recommendation is for the Standing Committee of the

Bern Convention and the European Commission to

adopt express guidance concerning hybridization.

INTRODUCTION

Hybridization is an increasingly significant biodiversity

conservation problem.1This is especially so when wild

animals interbreed with domestic ones or with alien

species introduced by man. The adverse effects of the

‘introgression’ of foreign genes into original popula-

tions poses a significant threat to many populations of

wild animals, and may in some cases even lead to the

genetic extinction of entire species. For instance, inter-

breeding with domestic dogs poses an important threat

to the dingo (Canis lupus dingo),2the highly endan-

gered Ethiopian wolf (Canis simensis)3and various

other canids.4Hybridization affects many species

around the world. To give an idea, at a European scale,

one study has estimated that at least 6% of all mammal

species are subject to some degree of hybridization.5

Interbreeding with domestic and exotic species and

other cases of anthropogenic (human-caused) hybrid-

ization are widely perceived as biodiversity conservation

problems. In addition, there are many cases of so-called

‘natural’ hybridization, involving two wild, indigenous

(sub)species.6This may or may not, depending on the

circumstances and one’s perspective, constitute, or be

perceived as, a conservation problem.7The focus of the

present article is restricted to anthropogenic hybridiza-

tion, which is the most problematic type from a conser-

vation point of view. Although natural hybridization also

gives rise to intricate legal questions, it is beyond the

scope of a single article to deal with both categories.

Incidentally, there are also interesting cases where the

boundaries between the two categories are blurred – for

instance, when hybridization is the consequence of the

natural adaptation of species to anthropogenic climate

change.8

1Generally, see J.M. Rhymer and D. Simberloff, ‘Extinction by Hybrid-

ization and Introgression’, 27 Annual Review of Ecology and System-

atics (1996), 83; F.W. Allendorf et al., ‘The Problem with Hybrids:

Setting Conservation Guidelines’, 16:11 Trends in Ecology and Evo-

lution (2001), 613; and J. Mallet, ‘Hybridization as an Invasion of the

Genome’, 20:5 Trends in Ecology and Evolution (2005), 229.

2See, e.g., A.E. Elledge et al., ‘Assessing the Taxonomic Status of

Dingoes Canis familiaris dingo for Conservation’, 36:2 Mammal

Review (2006), 142; M.J. Daniels and L. Corbett, ‘Redef‌ining

Introgressed Protected Mammals: When is a Wildcat a Wild Cat and

a Dingo a Wild Dog?’, 30:3 Wildlife Research (2003), 213.

3D. Gottelli et al., ‘Molecular Genetics of the Most Endangered

Canid: The Ethiopian Wolf Canis simensis’, 3:4 Molecular Ecology

(1994), 301.

4J.A. Leonard, J. Echegaray, E. Randi and C. Vilà, ‘Impact of Hybrid-

ization with Domestic Dogs on the Conservation of Wild Canids’, in:

M.E. Gompper (ed.), Free-ranging Dogs and Wildlife Conservation

(Oxford University Press, 2013), 70.

5See J. Mallet, n. 1 above.

6M. Genovart, ‘Natural Hybridization and Conservation’, 18:6 Biologi-

cal Conservation (2009), 1435; F.W. Allendorf et al., n. 1 above.

7See M. Genovart, n. 6 above; and F.W. Allendorf et al., n. 1 above.

8A clear example is the recent, presumably climate-induced arrival of

the originally African long-legged buzzard (Buteo ruf‌inus cirtensis)as

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Review of European Community & International Environmental Law

RECIEL 23 (1) 2014. ISSN 2050-0386 DOI: 10.1111/reel.12052

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