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

Area of Science:

• Ecology
• Agricultural Science
• Conservation Biology

Background:

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

Purpose of the Study:

• To investigate how plant diversity affects multitrophic interactions in agricultural and natural ecosystems.
• To determine if plant diversity elicits top-down or bottom-up effects and how these vary by ecosystem type and management.
• To assess the potential of crop diversification for pest management.

Main Methods:

• Conducted a meta-analysis of 149 field studies across five continents.
• Compared invertebrate natural enemy-to-herbivore abundance ratios under varying plant diversity.
• Differentiated analysis between croplands (organic and nonorganic) and natural ecosystems (grasslands and forests).

Main Results:

• Increasing plant diversity led to significantly higher natural enemy-to-herbivore ratios in croplands (846% organic, 148% nonorganic), indicating top-down control.
• In grasslands and forests, plant diversity was linked to bottom-up effects, increasing both herbivore and predator populations (4.73% and 21.2% ratio increase, respectively).
• Biodiversity effects on productivity are complex and not solely due to plant-plant interactions.

Conclusions:

• Plant diversity influences multitrophic interactions differently in croplands versus natural ecosystems.
• Top-down control dominates in diverse croplands, aiding pest management, while bottom-up effects prevail in diverse grasslands and forests.
• Crop diversification presents a promising strategy for sustainable agriculture and preventative pest management.