Biodiversity and ecosystem stability in a decade-long grassland experiment

Area of Science:

• Ecology
• Environmental Science

Background:

• Human activities often simplify ecosystems, raising questions about the relationship between species diversity and ecosystem functioning.
• While biodiversity's impact on ecosystem productivity is established, its effect on ecosystem stability remains a subject of debate.

Purpose of the Study:

• To experimentally test the long-term effects of plant species diversity on ecosystem stability.
• To investigate how varying species numbers influence temporal stability of ecosystem productivity in a prairie environment.

Main Methods:

• A decade-long field experiment directly controlled the number of perennial prairie plant species.
• Monitored year-to-year variations in plant species abundance, ecosystem productivity, and climate conditions.
• Measured temporal stability of ecosystem annual aboveground plant production at different time intervals (2, 5, and 10 years).

Main Results:

• Higher plant species diversity significantly increased the temporal stability of ecosystem annual aboveground plant production.
• Ecosystem stability was positively correlated with root mass (perenniating biomass) and tended to increase with plot maturation.
• Despite lower individual species stability, overall ecosystem stability was enhanced by diversity through portfolio and overyielding effects, not covariance.

Conclusions:

• Biodiversity is a key driver of ecosystem temporal stability, enhancing the reliability of ecosystem functions.
• Maintaining or increasing plant diversity can lead to more stable and sustainable provision of ecosystem services, such as livestock fodder and biofuels.
• The findings support the diversity-stability hypothesis, underscoring the importance of biodiversity for resilient ecosystems.