3.6. Summary of findings
Insights from this case study suggest that interactions between domestic
dogs and dingoes, and hence risk for disease transmission at the
wild−domestic interface, are more likely to occur around the communities
during the dry season, whereas the risk seems to be increased in bush
areas away from the communities during the wet season. The former is
likely driven by the availability of freely accessible food sources
which attracts wild dogs and the presence of roaming domestic dogs, and
the latter is apparently driven by an intensification of hunting
activities with domestic dogs coupled with a higher level of wild dog
activity in these same areas. These two potential disease pathways need
to be incorporated into any model of disease spread within this
ecosystem.
Monitoring of roaming domestic dogs at the study site demonstrates that
most dogs will “stay at home” and only explore their immediate
surroundings. However, there is a proportion of the population
(estimated to be 29% by Hudson et al. (2017)) which will explore their
surroundings, including areas of bushland where contact with wild dogs
is possible. Dog factors such as age, sex, and neuter status do not
appear to be strong predictors of this roaming behaviour. However,
recognition of the heterogeneity of roaming behaviour in populations of
roaming dogs in Indigenous communities presents an opportunity to reduce
disease spread at the wild−domestic interface (Hudson et al., 2016).
Wild dogs often reside near human settlements (Allen et al. 2013;
Sparkes et al. 2016) and their home range can be configured
around supplementary food sources, such as mine sites and refuse
facilities (Allen et al. 2013; Newsome et al. 2013;
McNeill et al., 2016). It is likely that sites are more frequented when
wild dogs have unrestricted access to resources such as food, water and
vegetation coverage (Sparkes et al. 2015). Therefore, locations
such as waste disposal sites pose a risk because higher wild dog
activity around human-provided resources could increase contact
opportunities with free-roaming domestic-type dogs (Fleming et
al. 2001; Newsome et al. 2013; Bombara et al. 2017b;
Hudson et al., 2016; Hudson et al., 2017), and provide opportunity for
disease transmission between the two dog populations. The findings of
hybridisation studies also support the existence of this wild−domestic
interface (Bombara et al., 2017a; Gabriel-Rivet et al., 2021c). In
addition, greater activity in wild dog populations between dusk and dawn
have been observed, due to aversion to human activity and more
profitable foraging opportunities following dusk (Allen et al.2013; Newsome et al. 2013; Ward et al., 2021). Thus contacts are
more likely during these times of the day. The presence of
community-associated food resources which attract wild dogs –
particularly during the dry season − need to be incorporated into
disease spread models. Monitoring of these sites to estimate contact
rates is a priority for such research.
The role that hunting might play at the study site, and more broadly
across northern Australia, needs more investigation. During hunting
trips, dogs can travel in the bush for long distances (up to 4 km) and
for a considerable amount of time (up to 9 h), whilst being remotely
monitored by hunters using GPS technology. This hunting behaviour can
increase the chances of encountering wild dogs (Gabriel-Rivet et al.,
2019a). Studies in the NPA (Gabriel-Rivet et al., 2021b) indicate that
opportunities for encounters are likely, which is consistent with the
results of a previous survey of Australian hunters (Sparkes et al.,
2016), in which 50% of the hunters interviewed witnessed at least one
encounter with wild dogs throughout their hunting experience. However,
the probability or rate of effective contact needs quantification for
the purpose of disease spread modelling to determine the relative risk
posed by this interface compared to others such as the wild−domestic
peri-community interface.