30 – Recovery of the red-finned blue-eye^383consequences. Genetic monitoring undertaken in 2010, and compared with
samples collected in the 1990s, revealed both low levels and ongoing loss of genetic
diversity in red-finned blue-eye (Faulks et al. 2016). Thus, increasing genetic
diversity to avoid inbreeding depression must become a management priority.
However, allowing natural dispersal of red-finned blue-eye during f lood events is
fraught due to the threat posed by gambusia, necessitating careful planning and
monitoring of translocated populations to increase genetic diversity and reduce
extinction risk.
Discussion
Adaptive management of threatened species is dependent on real-time monitoring
to provide timely feedback on the effectiveness of interventions. However,
threatened species managers rarely have the benefit of controlled experimentation
on which to base decisions due to limitations imposed by distribution, habitat
specificity and rarity of their target species, and the urgency with which
management often needs to be undertaken. The Red-finned Blue-eye Recovery
Program at Edgbaston is an example of such an unreplicated, uncontrolled
experiment. The program of barrier fencing, gambusia eradication and red-finned
blue-eye translocation does not have absolute ‘controls’ – that option simply does
not exist. Instead, managers have established a series of one-off trials testing
various management interventions and tactics. Each spring and intervention is
unique, but through repetition of approach coupled with monitoring, inference can
be drawn about the effectiveness of particular actions. For example, the fact that
gambusia colonised only one of five fenced springs suggests that barrier fencing is
effective, despite the fact that this was an uncontrolled treatment.
Insight comes through coupling regular and consistent monitoring with
management interventions over time. Periodicity of monitoring will be determined
by species attributes (e.g. longevity, generation cycle) and the nature of the threat(s)
and management responses. In this case, threats are episodic (triggered by rain
events), management responses are prolonged, and red-finned blue-eye are capable
of rapid population growth under favourable conditions but they are also
susceptible to rapid declines. Monitoring every 2–3 months has proven adequate to
track population persistence, capture population f luctuations and identify trends.
Monitoring helps overcome ‘management paralysis’ by validating effective
interventions and allowing failures to be recognised and either aborted or
remedied. In the absence of remedial action, red-finned blue-eyes were facing
extinction. The novel and untested manipulative interventions implemented at
Edgbaston have resulted in red-finned blue-eye now occupying seven springs
instead of only one (NW30/70) had no action been taken.
Although a rigorous experimental framework is ideal, in many circumstances
threatened species managers are severely limited from realising this ideal.