Fecal standing crop with real time correction using scat detection dogs to estimate population density

Population density is fundamental information for assessing the
conservation status of species and support management and conservation
actions for in situ populations, but is unknown for many forest species
due to their difficulty in detection. The Fecal Standing Crop (FSC) method
using detection dogs is an alternative for cryptic or elusive species. An
intrinsic difficulty of FSC is the ability to find fecal samples in the
field and to estimate the probability of which feces detection is
influenced by degradation due to climatic conditions. Our goal was to
propose a concurrent FSC parameter estimation using a scat detection dog
under different climatic conditions and apply those parameters in a wild
deer population. Ten fecal samples of gray brocket deer (Subulo
gouazoubira) were placed weekly in a transect (24 x 1200 m) in both dry
and wet seasons (12 weeks each). A scat detection dog was then employed to
find experimental fecal samples to determine the FSC parameters that were
subsequently used with naturally occurring fecal samples (also
dog-detected) to estimate population density. The oldest dog found samples
were 21 (Dry) and seven (Wet) days after placement, resulting in dog
efficiency of 23% (Dry) and 30% (Wet). Adjusting the model to account for
efficiency and scat durability, we estimated similar, seasonal, densities
of 4.54 individuals km-2 (SD = 2.21, Dry) and 5.52 indiv. km-2 (SD = 3.71,
Wet). Synthesis and applications: Our results demonstrate that our
concurrent methodology corrected the effects of weather and habitat on FSC
parameters thereby allowing for accurate population density estimation.
Additionally, this method can provide reasonably precise density estimates
with a logistically feasible sample size, as demonstrated by simulation.
Following our recommendations, this method allows a reliable estimate of
population density because it incorporates any influence of study area,
dog ability, and climate in fecal sample detection, providing fundamental
information for the conservation of many cryptic and elusive species.