Data for: Testing the match-mismatch hypothesis in bighorn sheep in the context of climate change

In species with long gestation, females commit to reproduction several
months before parturition. If cues driving conception date are
uncoupled from spring conditions, parturition could be mistimed. Mismatch
may increase with global change if the rate of temporal changes in autumn
cues differs from the rate of change in spring conditions. Using 17 years
of data on climate and vegetation phenology, we show that autumn
temperature and precipitation, but not vegetation phenology, explain
parturition date in bighorn sheep. Although autumn cues drive the timing
of conception, they do not predict conditions at parturition in spring. We
calculated the mismatch between individual parturition date and spring
green-up, assessed whether mismatch increased over time and investigated
the consequences of mismatch on lamb neonatal survival, weaning mass and
overwinter survival. Mismatch fluctuated over time but showed no temporal
trend. Temporal changes in green-up date did not lead to major fitness
consequence of mismatch. Detailed data on individually marked
animals revealed no effect of mismatch on neonatal or overwinter
survival, but lamb weaning mass was negatively affected by mismatch.
Capital breeders might be less sensitive to mismatch than income breeders
because they are less dependent on daily food acquisition. Herbivores in
seasonal environments may access sufficient forage to sustain lactation
before or after the spring ‘peak’ green-up, and partly mitigate the
consequences of a mismatch. Thus, the effect of phenological mismatch on
fitness may be affected by species life-history, highlighting the
complexity in quantifying trophic mismatches in the context of climate
change.