19
3. Would mass rearing and release of beetles be required?
A single cow deposits about 2.5kg of faeces between
10 and 24 times a day in one large, or several smaller pats.
If we consider that 20 beetles are required to bury 1kg of
dung in approximately 48 hours, then between 500 and
1 200 beetles are needed to process the dung produced by
a single cow in one day. On average, 309 individual beetles
are collected from each mine site during each sampling
trip. Therefore ,we can safely assume that the numbers
of naturally occurring beetles required to process all the
dung produced even by a small herd of cattle will initially
be insufficient to bury all of their dung on rehabilitated
mine sites. Although the population would grow with time,
mass-rearing and release would provide an initial boost to
the population and would be recommended.
Recommendations for future research
The benefits of dung beetle activity are well established for
agro-ecosystems and, based on the results of this project, have,
for the most part, been shown to apply to reclaimed mine sites.
Therefore, future research should focus on methods for the
application, management and monitoring of dung beetles on
reclaimed mines.
Livestock would need to be introduced to a number of
reclaimed mine sites. Ideally sites could include some of those
assessed in this project as we have a good understanding of
the baseline dung beetle assemblage and environmental
conditions. Livestock could be introduced to suitably grassed,
fenced areas and rotated after a period of four to six weeks.
Once livestock have been introduced, we could then attempt
to answer the following research questions:
y
y
Given the provision of dung producing livestock, how
would naturally occurring versus mass-reared and released
dung beetle populations fluctuate and influence their
environment?
y
y
How do naturally present dung beetle assemblages respond
to the presence of dung-producing livestock on reclaimed
mines?
y
y
When applying mass-reared beetles, at what point can we
be certain that a sufficiently numerous and self-sustaining
population of beetles has been established?
y
y
Is the vegetation growth response to grazing and dung
beetle activity sufficient to provide a sustainable grazing
system on reclaimedmine sites?What quantities of livestock
could be supported?
