Plant diversity modifies multi-trophic interactions in croplands, grasslands and forests

Area of Science:

• Ecology
• Agricultural Science
• Biodiversity Research

Background:

• Multitrophic interactions are crucial for ecosystem structure and function.
• The impact of plant diversity on these interactions across different ecosystems is not fully understood.
• Understanding these dynamics is key for ecosystem management and agricultural sustainability.

Purpose of the Study:

• To investigate how plant diversity influences the direction and predictability of multitrophic interactions.
• To compare these effects in agricultural (croplands) versus natural ecosystems (grasslands and forests).
• To determine the balance of top-down and bottom-up effects under varying plant diversity.

Main Methods:

• A meta-analysis synthesizing data from 149 field studies across five continents.
• Comparison of invertebrate natural enemy-to-herbivore abundance ratios in response to increased plant diversity.
• Distinguishing between top-down control (predator-driven) and bottom-up effects (productivity-driven).

Main Results:

• Increasing plant diversity led to a higher ratio of natural enemies to herbivores in croplands (846% organic, 148% non-organic), indicating top-down control.
• In grasslands and forests, increased plant diversity showed bottom-up effects, enhancing both herbivore and predator populations.
• The enemy-to-herbivore ratio increased by 4.73% in grasslands and 21.2% in forests.

Conclusions:

• Biodiversity effects on productivity involve complex top-down and bottom-up interactions, varying by ecosystem and management.
• Crop diversification can be a strategy for preventative pest management, enhancing agricultural sustainability.
• Plant diversity's influence on multitrophic interactions is context-dependent, impacting ecosystem services differently.