Temperature and functional traits influence differences in nitrogen uptake capacity between native and invasive...

Area of Science:

• Plant Ecology
• Invasive Species Biology
• Physiological Ecology

Background:

• Invasive plant performance is often assumed static, but temperature influences growth.
• Western North America shrublands and steppes are susceptible to invasive grasses.
• Understanding nitrogen (N) uptake differences is key to predicting invasive success.

Purpose of the Study:

• To examine temperature-dependent N uptake differences between native and invasive grasses.
• To investigate the role of morphological traits in N uptake across temperatures.
• To compare invasive annual grasses with native and non-native perennial grasses.

Main Methods:

• Compared N uptake and morphological traits of five grass species (two native, two invasive annual, one non-native perennial) at 5-25 °C.
• Applied data to path models to analyze correlations between morphology and N uptake.
• Focused on leaf and root N and mass as key morphological variables.

Main Results:

• N uptake differences were small at low temperatures but significant at high temperatures.
• At low temperatures, leaf traits influenced N uptake for all grasses.
• At high temperatures, invasive annual grasses relied solely on leaf traits, while perennials also depended on root traits for N uptake.

Conclusions:

• Invasive annual grasses face fewer morphological constraints on N uptake than perennial grasses.
• Warmer temperatures or increased warm periods may enhance the competitive advantage of invasive annual grasses.
• Temperature is a critical factor influencing the success of invasive grasses in western North America.