Data from: Digital recorders increase detection of Eleutherodactylus frogs

Improved methods for large-scale and long-term amphibian monitoring
projects would aid species status assessments and identification of
potentially declining species (e.g., Stuart et al. 2004). Acoustical
surveys allow researchers to quickly determine species presence and
calling activity level (Lips et al. 2001; Zimmerman 1994). The North
American Amphibian Monitoring Program, a large-scale monitoring effort,
uses acoustical surveys to monitor species in ponds and wetlands (United
States Geological Survey 2004). A challenge of this approach is accurate
species identification, which is particularly problematic in a tropical
area with high anuran species diversity (e.g., anuran species richness in
the Neotropics was greater than in the Neartic, Duellman 1999).
Furthermore, abundant or loud species may lower the detection probability
of other species. An assumption that needs to be tested in acoustical
surveys is that detection is highly correlated with the species presence
or activity. Without an appropriate correction for detection probability,
data will not accurately reflect the status of the species (MacKenzie et
al. 2002). This may result in inappropriate management decisions that
could waste time and money. Digital recorders can be used as a standard
method for species detection and determination of calling activity level
in amphibian choruses in long-term monitoring projects. Digital recordings
can be stored and transferred easily and can allow experts to analyze the
recordings at their convenience. In addition, loud or abundant species can
be filtered using computer software to increase the detection of other
species. I tested the hypothesis that detection of species presence and
calling activity level in anuran choruses will be higher when recordings
are analyzed with the help of computer software compared to only hearing
the recordings. The resulting increase in detection should result in
improved population status data and reduced false negatives during species
inventories (i.e., when a species is not detected due to interference).