5 – The extent and adequacy of monitoring for Australian threatened frog species^65responses to climate change. This information has driven the establishment of ex
situ insurance populations as well as pre-emptive translocations to habitats
predicted to be more resilient to changes in hydrology (Kim Williams pers. comm.).
This assessment identified that some threatened frogs are detected in general
biodiversity monitoring programs that target a broad range of species (e.g.
Earthwatch); however, although this information is valuable, it is usually inadequate
for providing guidance on population trends and informing the management of
threatened species. Most threatened frog species require targeted monitoring (fit-for-
purpose) to ensure adequate detectability, with detection rates of rare frog species in
multi-species/surveillance monitoring programs being generally low (Pellet and
Schmidt 2005). Finally, although the focus was on monitoring of threatened species,
surveillance monitoring of Least Concern and Data Deficient species is also
necessary (Petrovan and Schmidt 2016). Surveillance monitoring programs can
potentially identify early stages of decline and may enable threats to be mitigated
before species experience widespread, severe declines. Conserving species before they
decline is more cost effective than implementing remedial actions.
A range of survey techniques have been employed to monitor effectively
various threatened frog species in Australia including: spotlighting visual
encounter and acoustic surveys with simple counts; capture–mark–recapture
sampling; tadpole survey; and breeding site occupancy. New technologies such as
eDNA and automated acoustic data loggers also have potential application for
monitoring frog populations, but as yet have not been widely applied to threatened
frog species. Irrespective of the method(s) used, key criteria that need to be meet to
ensure effective monitoring are: (1) adequate detection probabilities at appropriate
sampling units (individuals, choruses, populations) in order to be able to measure
temporal change; (2) appropriate sampling techniques with respect to the ecology,
behaviour, life history, and distribution of the species; (3) monitoring satisfying
management and policy objectives; and (4) monitoring is sustainable with respect
to resources availability.
The first step in successful monitoring, is to clearly articulate management and
policy objectives, and then determine what measures are needed to meet these
objectives. In some instances, threatened species monitoring will be focused on
macro-level changes (e.g. site occupancy). Often these measures can be relatively
easy and affordable to collect for threatened frogs, because adults of many species
form conspicuous breeding choruses at relatively predictable times of year. For
example, three 5-minute acoustic surveys during the breeding season can provide
strong inference on presence/absence at a site level (Scheele et al. 2012, 2014a).
However, for species with detailed recovery plans and specific management
interventions, more sensitive measures of population trajectories are often
required. In such cases, it is important that monitoring can discern the
effectiveness of management.