Differing nutritional constraints of consumers across ecosystems

Area of Science:

• Ecology
• Biogeochemistry
• Nutrient Cycling

Background:

• Stoichiometric mismatches between resources and consumers influence ecological interactions like predation and herbivory.
• Nitrogen (N) and phosphorus (P) mismatches are well-studied in aquatic systems, but less so in terrestrial communities.
• Understanding resource-consumer stoichiometry is crucial for predicting consumer behavior and growth.

Purpose of the Study:

• To characterize nutritional constraints in a terrestrial arthropod community.
• To compare terrestrial resource-consumer stoichiometry with aquatic (stream and lake) ecosystems.
• To investigate the potential for nitrogen and phosphorus limitation in terrestrial consumers.

Main Methods:

• Collected and analyzed stoichiometric data (N and P content) for terrestrial arthropod consumers and their resources.
• Compared terrestrial N:P ratios with existing data from stream and lake ecosystems.
• Assessed potential nutrient limitation based on resource-consumer stoichiometric relationships.

Main Results:

• Nitrogen and phosphorus levels varied significantly across different trophic levels in the terrestrial community.
• Terrestrial herbivores may face strong nitrogen limitation due to high N:P ratios in their diet.
• Low phosphorus content in plant foliage suggests potential phosphorus limitation for herbivores, comparable to nitrogen limitation.
• Arthropod predators may also experience significant phosphorus limitation.
• Nutrient limitation patterns in terrestrial systems resemble those in aquatic ecosystems.
• Terrestrial consumers exhibit simultaneous strengthening or weakening of N and P limitation, unlike the trade-off observed in lakes.

Conclusions:

• Phosphorus may be a critical limiting nutrient in terrestrial ecosystems, often overlooked in ecological studies.
• Similar stoichiometric constraints operate across terrestrial, stream, and lake ecosystems.
• Understanding nutrient dynamics is essential for comprehending terrestrial food web structures and functions.