A climate-driven switch in plant nitrogen acquisition within tropical forest communities

Area of Science:

• Tropical ecology
• Plant nutrition
• Climate change impacts

Background:

• Understanding plant nutritional strategies is crucial for predicting tropical forest responses to climate change.
• Nitrogen nutrition is a key factor limiting plant growth and photosynthesis in these ecosystems.
• Previous research has not clearly defined the nitrogen nutrition strategies of diverse tropical plant species.

Purpose of the Study:

• To investigate the nitrogen nutrition strategies of various tropical plant species with different growth habits.
• To determine if tropical plant species specialize in different nitrogen pools or utilize a common resource.
• To examine how precipitation changes influence the nitrogen source utilization by tropical plant communities.

Main Methods:

• Utilized stable isotope natural abundances to trace nitrogen sources.
• Analyzed nitrogen uptake strategies across diverse species including trees and ferns from canopy and subcanopy layers.
• Assessed responses to variations in precipitation patterns.

Main Results:

• A diverse group of tropical plant species relied on a common pool of inorganic nitrogen.
• No evidence of specialization on different nitrogen pools was found among the studied species.
• Species exhibited an abrupt, synchronized shift in their dominant nitrogen source in response to precipitation changes.

Conclusions:

• Tropical plant species demonstrate a coherent strategy to exploit the most available soil nitrogen.
• The observed community-wide flexibility in nitrogen uptake suggests physiological adaptation to changing nitrogen cycling.
• Diverse tropical forests possess the capacity to track climate-driven alterations in nitrogen availability.