Conservation implications of a mismatch between data availability and
demographic impact
Abstract
Cost-effective use of limited conservation resources requires
understanding which data can most contribute to alleviating biodiversity
declines. Interventions might reasonably prioritise life-cycle
transitions with the greatest influence on population dynamics, yet some
contributing vital rates are particularly challenging to document; such
pragmatic decision-making risks suboptimal management if less is known
about influential rates. We aimed to explore whether study effort aligns
with demographic impact on population growth rate, λ. We parameterised a
matrix population model using meta-analysis of vital rates for the
common eider (Somateria mollissima), an increasingly threatened yet
comparatively data-rich species of seaduck. Female common eiders exhibit
intermittent breeding, with some established breeders skipping one or
more years between breeding attempts. We accounted for this behaviour by
building breeding propensity (= 0.72) into our model with a discrete and
reversible ‘non-breeder’ stage (to which surviving adults transition
with a probability of 0.28). The transitions between breeding and
non-breeding states had twice the influence on λ than fertility (summed
matrix-element elasticities of 24% and 11%, respectively), whereas
almost 15 times as many studies document components of fertility than
breeding propensity (n = 103 and n = 7, respectively). Through
comparative re-analyses, we find similar results for two amphibian
species, further supporting our finding that study effort does not
always occur in proportion to relative influence on λ. Our workflow
could form part of the toolkit informing future investment of finite
resources, to avoid repeated disconnects between data needs and
availability thwarting evidence-driven conservation.