Earth's average temperature has risen by 1.4 degrees Fahrenheit (0.8 degrees Celsius) over the past century, according to the Environmental Protection Agency (EPA). Temperatures are projected to rise another 2 to 11.5 degrees F (1.133 to 6.42 degrees C) over the next 100 years. 

Nitrogen (N) and phosphorus (P) are important nutrient in terrestrial ecosystems and they control many biogeochemical processes. Increased global climate change and human activities bring about more and more N and P inputs to various systems. This will lead to an enrichment of nutrient in vegetation community soil nutrient availability would be increased due to enriched N and P inputs and these should have been a good thing for plants, as well as the ecosystem. However, these results may bring unpredictable consequences when the nutrient balance of ecosystem is broken especially for ecological sensitive regions. 

In the vast outback of northwester China, locates the semi-arid alpine grassland of Kunlun Mountain, with an altitude varying from 2900 m to 3600 m. It is one of the most important areas for livestock grazing in Xinjiang province of China. Ecological system here is particularly sensitive to climate change, and further, to the consequent nutrient addition. Hence, nutrient additions may affect plant nutrient resorption, and alter plant community composition and nutrient cycling in ecosystems. However, there is still much debate about how changes in nutrient availability affect plants nutrient resorption.  

And that is what LI Lei has been doing with his colleague at the Xinjiang Institute of Ecology and Geography. They picked two dominant grass species as their objects and tried to investigate the variation of nutrient resorption between these two grasses through nutrient addition experiments. Researchers took series of field experiments with contrasting nutrients (N and P) addition rates to examine the intraspecific responses of nutrient resorption to N and P addition.  

Findings of this study would be useful for understanding nutrient utilization strategies of alpine perennial grass species, and differences between these two grass species in term of the N and P resorption response to nutrient additions. 

Scientists find that P fertilizer addition decreased P resorption proficiency for both grass species, and P resorption proficiency was generally more sensitive than P resorption efficiency. Therefore, nutrient resorption proficiency is more sensitive than efficiency to increased nutrient availability and is a good indicator for nutrient internal use.  

Moreover, their research suggests that nutrient additions altered the nutrient cycling and storage in plants, and N or P fertilization could alter the plant community composition by the indirect influences on nutrient cycling in ecosystems due to the species-specific responses of nutrient resorption to nutrient addition. 

The study provides detailed insights about the nutrient resorption sensitivity to short-term nutrient additions.  This will help to know the effect of global climate change and human activities on plant community composition and ecosystem stability of Kunlun Mountain which is sensitive to these changes. 

The findings were published in the journal Environmental and Experimental Botany . For more details, please refer to http://dx.doi.org/10.1016/j.envexpbot.2016.03.008 

contact

Lei Li

lilei@ms.xjb.ac.cn