Data from: Changing climate cues differentially alter zooplankton dormancy dynamics across latitudes

1. In seasonal climates, dormancy is a common strategy that structures
biodiversity and is necessary for the persistence of many species. Climate
change will likely alter dormancy dynamics in zooplankton, the basis of
aquatic food webs, by altering two important hatching cues: mean
temperatures during the ice-free season, and mean day length when lakes
become ice free. Theory suggests that these changes could alter diversity,
hatchling abundances and phenology within lakes, and that these responses
may diverge across latitudes due to differences in optimal hatching cues
and strategies. 2. To examine the role of temperature and day length on
hatching dynamics, we collected sediment from 25 lakes across a 1800 km
latitudinal gradient and exposed sediment samples to a factorial
combination of two photoperiods (12 and 16 hours) and two temperatures
(8°C and 12 °C) representative of historical southern (short photoperiod,
warm) and northern (long photoperiod, cool) lake conditions. We tested
whether sensitivity to these hatching cues varies by latitudinal origin
and differs among taxa. 3. Higher temperatures advanced phenology for all
taxa, and these advances were greatest for cladocerans followed by
copepods and rotifers. Although phenology differed among taxa, the effect
of temperature did not vary with latitude. The latitudinal origin of the
egg bank influenced egg abundance and hatchling abundance and diversity,
with these latter effects varying with taxa, temperature and photoperiod.
4. Copepod hatchling abundances peaked at mid latitudes in the high
temperature and long photoperiod treatments, whereas hatchling abundances
of other zooplankton were greatest at low latitudes and high temperature.
The overall diversity of crustacean zooplankton (copepods and cladocerans)
also reflected distinct responses of each taxa to our treatments, with the
greatest diversity occurring at mid latitudes (~56° N) in the shorter
photoperiod treatment. 5. Our results demonstrate that hatching cues
differ for broad taxonomic groups that vary in developmental and
life-history strategies. These differences are predicted to drive
latitude-specific shifts in zooplankton emergence with climate change, and
could alter the base of aquatic food webs.