Environmental Engineering Reference
In-Depth Information
Table 2
Interaction of weather conditions and the suitability for undertaking mortality searchers
with dogs
Wind Speed
Low
Wind Speed
Medium
Wind Speed
High
Wind Speed
Extreme
Ideal weather conditions
Good weather conditions
Ok weather conditions
Poor weather conditions
Temperature
Extreme Cold
Temperature
Mild to warm
Temperature
Extreme Heat
Topography and Vegetation
In addition to the weather, other factors such as topography and vegetation may also
influence scenting ability. Dense or high vegetation reduces the effect of wind at
ground level and dogs need to be given extra freedom to “hop” or “bounce” through
the vegetation. In the field it is often easier to engage the dog by stratifying the site
based on different vegetation types and thus it is important to be able to adapt meth-
odology even within a single survey. In flat terrain with ideal weather conditions
there is no need to search to the full perimeter of the survey area except on the up
wind side. This is because the dog does not recognise the invisible boundary of the
survey area and will readily detect scents 20-40 m away (and further). In contrast,
steep and undulating sites do not provide the same ease of detection and it is impor-
tant to allow the dogs to search to the highest and lowest depressions and slopes in
the survey area.
Target Species
As mentioned previously, there is a great deal of difference in the detectability of
large birds compared with micro bats for both dogs and humans. Dogs undertaking
surveys need to be target trained for both birds and bats if this is the objective of the
carcass survey. In this case, searcher efficiency trials should test for both types of
carcasses to ensure high and reliable detectability. Factors such as weather and veg-
etation have less influence on overall detectability for large species, as the scent of
a large carcass is much stronger then for smaller carcass, under similar conditions.
Therefore it is important when developing search protocols to consider the objec-
tives of the carcass detection program.
