A framework for assessing ecosystem dynamics in response to chronic resource alterations induced by global change

Area of Science:

• Ecology
• Environmental Science
• Global Change Biology

Background:

• Global changes, including elevated CO2 and nitrogen deposition, induce chronic resource alterations, unlike pulse disturbances.
• Existing disturbance-based ecological frameworks are insufficient for predicting responses to these ongoing changes.

Purpose of the Study:

• To present a conceptual framework, the hierarchical-response framework (HRF), for assessing ecological change under chronic resource alterations.
• To provide a theoretical basis for testing hypotheses on ecosystem dynamics and sensitivity to global change drivers.

Main Methods:

• The HRF organizes ecological change mechanisms into a temporal hierarchy: individual (physiological/metabolic) responses, community species reordering, and species loss/immigration.
• It links these mechanisms to ecosystem attributes like species longevity, biogeochemical cycling rates, biodiversity, and trophic complexity.

Main Results:

• The HRF predicts nonlinear changes in ecosystem dynamics.
• It suggests that ecosystem sensitivity varies based on inherent attributes and interactions with natural disturbances and other global change drivers.
• The framework is designed for comparative analysis across ecosystems to understand differential sensitivities.

Conclusions:

• The HRF offers a robust approach to forecasting contemporary and future ecosystem dynamics under chronic environmental change.
• It can guide the design of coordinated, cross-site experiments for more reliable ecological predictions.
• Understanding these hierarchical responses is crucial for managing ecosystems facing global change.