Phenotypic Plasticity and Local Adaptation in a Wild Hibernator Evaluated through Reciprocal Translocation

Area of Science:

• Ecology
• Climate Change Biology
• Animal Behavior

Background:

• Phenological shifts are key ecological responses to climate change, often driven by phenotypic plasticity.
• The limits of plasticity and its sufficiency for maintaining local adaptation are not fully understood.
• In Columbian ground squirrels (Urocitellus columbianus), increased winter precipitation causes phenological delays and reduced fitness.

Purpose of the Study:

• To assess the extent of phenotypic plasticity in emergence dates across natural elevation gradients in Columbian ground squirrels.
• To investigate the relationship between emergence dates and individual annual fitness in this species.
• To determine if phenotypic plasticity is sufficient to buffer against environmental changes impacting phenology.

Main Methods:

• A reciprocal translocation experiment was conducted across two Columbian ground squirrel populations separated by 500m in elevation.
• Natural monitoring and data collection were coupled with the translocation experiment.
• Emergence dates and annual fitness were recorded for resident and translocated individuals.

Main Results:

• Individuals in both populations exhibited plastic responses in emergence dates to spring temperature and winter precipitation.
• Translocated individuals adjusted their emergence dates, but still differed significantly from residents in adoptive populations.
• No significant differences in annual fitness were found among treatment groups, and no selection on emergence date was detected within the study year.

Conclusions:

• Phenotypic plasticity is sufficient for Columbian ground squirrels to respond to wide environmental gradients.
• The direct influence of emergence date variation on annual fitness warrants additional investigation.
• Further research is needed to fully understand the long-term implications of phenological plasticity on population dynamics and adaptation.