Assessing the value of monitoring to biological inference and expected management performance for a European goose population

1. Informed conservation and management of wildlife require sufficient
monitoring to understand population dynamics and to direct conservation
actions. Because resources available for monitoring are limited,
conservation practitioners must strive to make monitoring as
cost-effective as possible. 2. Our focus was on assessing the value of
monitoring to the adaptive harvest management (AHM) program for
pink-footed geese (Anser brachyrhynchus). We conducted a retrospective
analysis to assess the costs and benefits of a capture-mark-resight (CMR)
program, a productivity survey, and biannual population censuses. Using
all available data, we fit an integrated population model (IPM) and
assumed that inference derived from it represented the benchmark against
which reduced monitoring was to be judged. We then fit IPMs to reduced
sets of monitoring data and compared their estimates of demographic
parameters and expected management performance against the benchmark IPM.
3. Costs and the precision and accuracy of key demographic parameters
decreased with the elimination of monitoring data. Eliminating the CMR
program, while maintaining other monitoring instruments, resulted in the
greatest cost savings, usually with small effects on inferential
reliability. Productivity surveys were also expensive and some reduction
in survey effort may be warranted. The biannual censuses were inexpensive
and generally increased inferential reliability. 4. The expected
performance of AHM strategies was surprisingly robust to a loss of
monitoring data. We attribute this result to explicit consideration of
parametric uncertainty in harvest-strategy optimization and the fact that
a broad range of population sizes is acceptable to stakeholders. 5.
Synthesis and applications: Our study suggests that existing or potential
monitoring instruments for wildlife populations should be scrutinized as
to their cost-effectiveness for improving biological inference and
management performance. Using Svalbard pink-footed geese as a case study,
we show that the loss of some existing monitoring instruments may not be
as adverse as commonly assumed if data are jointly analyzed in an
integrated population model. Finally, regardless of the monitoring data
available, we suggest that conservation strategies that explicitly account
for uncertainty in demography are more likely to be successful than those
that do not.