Data from: Demographic compensation does not rescue populations at a trailing range edge

Species' geographic ranges and climatic niches are likely to be
increasingly mismatched due to rapid climate change. If a species'
range and niche are out of equilibrium, then population performance should
decrease from high-latitude "leading" range edges, where
populations are expanding into recently ameliorated habitats, to
low-latitude "trailing" range edges, where populations are
contracting from newly unsuitable areas. Demographic compensation is a
phenomenon whereby declines in some vital rates are offset by increases in
others across time or space. In theory, demographic compensation could
increase the range of environments over which populations can succeed and
forestall range contraction at trailing edges. An outstanding question is
whether range limits and range contractions reflect inadequate demographic
compensation across environmental gradients, causing population declines
at range edges. We collected demographic data from 32 populations of the
scarlet monkeyflower (Erythranthe cardinalis) spanning 11˚ latitude in
western North America and used integral projection models to evaluate
population dynamics and assess demographic compensation across the
species' range. During the 5-year study period, which included
multiple years of severe drought and warming, population growth rates
decreased from north to south, consistent with leading-trailing dynamics.
Southern populations at the trailing range edge declined due to reduced
survival, growth, and recruitment, despite compensatory increases in
reproduction and faster life history characteristics. These results
suggest that demographic compensation may only delay population collapse
without the return of more favorable conditions or the contribution of
other buffering mechanisms such as evolutionary rescue.