Does the temporal mismatch hypothesis match in boreal populations?

Area of Science:

• Ecology
• Evolutionary Biology
• Climate Change Biology

Background:

• The temporal mismatch hypothesis links fitness to the synchrony between offspring energetic needs and food availability.
• This hypothesis is foundational for studying climate warming's ecological impacts.
• Previous research has focused on the consequences of temporal mismatches, particularly in response to climate change.

Purpose of the Study:

• To investigate the prevalence and consequences of temporal mismatches in boreal bird populations.
• To evaluate whether prey synchrony or breeding timing itself is a better predictor of reproductive output.
• To question the primacy of the temporal mismatch hypothesis in explaining the evolution of breeding timing.

Main Methods:

• Comparative analysis of North European parid populations (great tit, blue tit, willow tit).
• Examination of phenological shifts in bird breeding and caterpillar prey over recent decades.
• Correlation of phenological changes with spring temperatures and assessment of breeding success in relation to synchrony and timing.

Main Results:

• Caterpillar and great tit phenologies advanced, correlating with spring temperatures; blue tit phenology did not show significant advancement.
• Great and blue tit breeding remained synchronous with their caterpillar food source.
• Synchrony significantly explained breeding success, but this effect was conditional on factors like caterpillar abundance and breeding density.
• Early breeding before peak synchrony appeared advantageous at higher latitudes, particularly for willow tits.

Conclusions:

• While prey synchrony is important for breeding success, it is not the sole driver and its effect is context-dependent.
• The temporal mismatch hypothesis alone is insufficient to explain the evolutionary pressures shaping bird breeding timing.
• Breeding strategies, especially at high latitudes, may involve anticipating food availability rather than solely relying on current synchrony.