Potential for bird-insect phenological mismatch in a tri-trophic system.

Area of Science:

• Ecology
• Climate Change Biology
• Phenology

Background:

• Climate change is altering the timing of biological events, leading to phenological asynchrony.
• Phenological asynchrony can cause population declines and disrupt ecosystem functions.
• There is a need for broad comparisons of phenological cue sensitivity across trophic levels.

Purpose of the Study:

• To compare the sensitivity of plant, insect, and bird phenology to temperature changes.
• To identify species and locations most vulnerable to phenological mismatches.
• To assess the potential for using vegetation green-up as a proxy for bird food resource timing.

Main Methods:

• Synthesized over 15 years of data on forest green-up, Lepidoptera emergence, and migratory bird arrival/breeding in eastern North America.
• Quantified phenological shifts in response to accumulated growing degree days (GDD).
• Analyzed latitudinal differences in phenological sensitivity and factors influencing bird arrival shifts.

Main Results:

• Plant and insect phenology showed similar strong sensitivity to GDD; bird phenology had lower sensitivity.
• Vegetation green-up and bird arrival were more sensitive to GDD at higher latitudes, but bird breeding timing was less sensitive.
• Migratory birds with slower migration, earlier arrivals, and northerly wintering grounds showed the greatest arrival shifts.

Conclusions:

• Similar temperature responses of vegetation green-up and insect emergence support using remote sensing for tracking food resource shifts.
• The plant-insect-bird system exhibits a higher potential for bird-insect phenological mismatch than insect-plant mismatch.
• Phenological decoupling risk is elevated at higher latitudes within the studied Eastern Temperate Forests ecosystem.