Abstract
Detection of animals is influenced by species traits, environment,
season and the methods used. Analytical techniques can address imperfect
detection, such as false absences, but data limitations hinder accurate
density estimation. Identifying field survey methods that optimize
detectability is therefore a high research priority, especially for
species of conservation concern. We consider a model species, the sugar
glider Petaurus notatus, to evaluate how optimizing detections
can affect survey outcomes. A literature meta-analysis found little
innovation in baiting approaches for sugar gliders over four decades.
Honey-based baits prevailed, despite emerging evidence of opportunistic
carnivory. We compared sugar glider detection probabilities using honey
and fish-based baits in a spatially explicit capture-recapture study.
Fish bait increased detections 33-fold, and density estimation (0.12ha-1) was only possible using the fish-baited data –
detections were too sparse using honey-bait to facilitate analysis.
Other factors that influence detectability include trap height and
habitat connectivity, which were top moderators in our meta-analysis,
but these may be secondary to the bait or lure used. By using (i)
species-specific bait that accounts for the biology of the target
species, and (ii) analytical tools to account for imperfect detection
and heterogeneous movement of animals, we achieved good enough detection
probabilities to undertake detailed analysis of the spatial ecology of
sugar gliders. Compared to honey-based baits (the prevailing approach of
other studies on this species), the high detection probability attained
with fish-based baits provides an improvement on conventional practices.
Our study is an important reminder that accounting for the biology of
the target species during survey effort may mean the difference between
collecting enough data for analysis or not. In the context of species
conservation, optimizing detection likelihoods is critical for answering
ecological questions about cryptic species, and our results demonstrate
the need to reappraise generic approaches when better information is
available.