Competition for time: Evidence for an overlooked, diversity-maintaining competitive mechanism

Area of Science:

• Ecology
• Plant Community Dynamics
• Biodiversity Maintenance

Background:

• Plant community diversity relies on understanding resource competition mechanisms.
• A key distinction exists between resource depletion affecting growth rate versus growth duration (competition for time).
• Current ecological theory often assumes competition reduces growth rate, overlooking competition for time.

Purpose of the Study:

• To introduce the concept of competition for time.
• To experimentally test the prevalence of competition for time in a Mediterranean annual grassland.
• To determine if competition for time is a significant mechanism for biodiversity maintenance.

Main Methods:

• Conceptual modeling of interacting species to define competition for time.
• Field experiment in Mediterranean annual grassland to assess competitive effects.
• Measurement of species' lifespan and growth rate responses to increased competition.

Main Results:

• Species experimentally subjected to increased competition primarily reduced their lifespan.
• No significant reduction in growth rate was observed in response to competition.
• Findings support competition for time as a relevant ecological mechanism.

Conclusions:

• Competition for time, defined by reduced growth duration, is a significant factor in plant communities.
• This mechanism may be overlooked in current ecological frameworks for biodiversity.
• Competition for time can organically generate diversity-maintaining trade-offs.