Diversity loss with persistent human disturbance increases vulnerability to ecosystem collapse.

Area of Science:

• Ecology
• Environmental Science
• Conservation Biology

Background:

• Human disturbances alter ecological systems, reducing diversity and functional attributes like invasion resistance.
• Theoretical predictions suggest diversity loss increases ecosystem collapse risk, but empirical evidence is scarce.

Purpose of the Study:

• To investigate the long-term effects of human disturbance on grassland ecosystem stability and diversity.
• To demonstrate the link between biodiversity loss, ecosystem function, and vulnerability to collapse.

Main Methods:

• Analysis of a degraded pyrogenic grassland ecosystem subjected to fire suppression and species loss.
• Comparison of ecosystem function (productivity, resilience, invasion resistance) under different disturbance regimes.
• Assessment of ecosystem response to fire re-introduction in relation to remnant native species diversity.

Main Results:

• Fire suppression led to species loss but increased productivity and invasion resistance, contrary to theory.
• The loss of biodiversity created a hidden vulnerability to collapse upon fire re-introduction.
• Remnant native species facilitated grassland persistence and prevented woodland conversion after fire.

Conclusions:

• Biodiversity loss, driven by human disturbance, can create deceptively stable but vulnerable ecosystems.
• High species diversity is critical for ecosystem stability and resilience, providing crucial buffering effects.
• Conservation of biodiversity is essential for maintaining ecosystem functions and preventing irreversible collapse.