Discussion
It is our understanding that the first fencing used for reptiles and
amphibians was for drift fence as a common sampling technique for
herpetofauna studies. We believe it is from this application where other
fencing guidance and best practices have been developed. As guidelines
have developed it shows that recommendations have moved away from highly
transparent, mesh type materials towards more opaque solid barriers.
It is our understanding that the use of readily available cheap
construction materials such as silt fence, shade, and hardware cloth has
been continually recommended despite the absence of any research to test
its suitability, effectiveness or assess animal behaviours when they
encounter such materials. Only in the most recent guidance has animal
behaviour been studied and highly opaque / solid fencing been
highlighted as a more suitable barrier type. Transparent mesh products
have ceased to be acknowledged as appropriate.
One factor that is raised for consideration between solid opaque
barriers is when drainage is a concern. Recommendations suggest using
pre-perforated solid products is a solution along with and should be
considered before any mesh product. If mesh has to be used, then this
should be used sparingly and with holes no larger than 3mm to minimize
the risk of animals becoming entangled.
There are also suggestions for the use of different material types
depending on the duration of the project and application. Lighter grade
products may be more suited for short term projects whereas heavier
grade products should be utilized for long term applications.
Shelters have also been identified as a useful addition to a fence line
to help provide animals refuge as they move along. The details of these
are yet to be determined and require further research.
We identified some significant difference in fence height above ground
ranges for a few species’ groups. Due to this we have split our
recommendations into small & large species variations for some species.
Further research needs to be conducted to improve the understanding of
fencing methods for unique species and localized biological knowledge
should always be considered.
Despite the variations and considerations that need to be made for
species variability (as not all species on all continents are the same
and will respond to fences the same) we believe these recommendations
will be suitable for most herpetofauna species currently and commonly
managed with fencing as a conflict management tool.
Recommendations also take into consideration the presence of other
species that may not be the “target” for the project. If a project is
focused on controlling the movement of turtles, the chances are there
may be other herpetofauna and other wildlife in the same habitat that
might benefit from the installation of a fence or barrier. As it is
known these species commonly share the same habitat types, we feel it
would be advantageous to include the anti-climb lip on all barriers.
When determining recommended heights, we have also taken the presence of
other species into consideration. A slight increase in height will only
positively impact the fences over all functionality without negatively
impacting the potential fence cost, installation method of long-term
maintenance. We have also standardized the depth of the fencing to be
installed below ground along with the inclusion of an anti-dig lip for
the same reasons.
Some guides also suggest an anti-climb top lip to be folded over, but
this is also inconsistent and may only be recommended for certain
species. The exact shape of this lip also varies and although more
research needs to be done on this, we have based our recommendations on
the most effective shape for most species known to date.
Some guides suggest folding an anti-dig lip in the ground, but this is
inconsistent across all of them.
We recommend that in the absence of best practice guidance and for ease
of wider implementation that anti-dig and anti-climb lips be applied to
all fences
The fence profile or shape is represented as a bold black line
comparable to the shape of the letter “C”. Fences can be installed on
their own as a “free-standing” barrier or attached to existing fences.
Irrespective of the installation method the measurements, features and
considerations should remain the same. The illustrations do not induce
details of any supportive posts or fixings that may be required to
ensure the fence is complete. The measurements shown are minimum
requirements appropriate to the specific fence barrier component for the
listed herpetofauna only. These recommendations are just recommendations
and should be considered as such.