Period doubling as an indicator for ecosystem sensitivity to climate extremes.

Area of Science:

• Ecology
• Climate Science
• Dynamical Systems Theory

Background:

• Dryland ecosystems face collapse due to predicted warmer, drier climates and increased extreme weather events.
• Formation of new drylands challenges native species' water-stress tolerance.

Purpose of the Study:

• To investigate the dynamics of dryland ecosystems under climate change using a vegetation model.
• To identify early warning indicators of ecosystem collapse.

Main Methods:

• Utilized a dryland-vegetation model simulating plant species with varying growth and drought-tolerance tradeoffs.
• Analyzed ecosystem dynamics under strong seasonal variability, characteristic of drylands.
• Investigated temporal period-doubling routes to chaos.

Main Results:

• Dryland ecosystems subjected to seasonal variability exhibit period-doubling leading to collapse.
• Fast-growing plants experience period doubling earlier and over wider chaotic ranges than stress-tolerant plants.
• Period-doubling signatures in power spectra serve as effective early indicators of ecosystem collapse.

Conclusions:

• Detection of period-doubling signatures in power spectra is a robust early warning indicator for ecosystem collapse.
• This indicator outperforms existing methods in predicting climate extremes and identifying vulnerable newly-formed drylands.
• The proposed indicator is applicable to other ecosystems, including consumer-resource and predator-prey systems, under specific conditions.