Location: Livestock and Range Research LaboratoryTitle: Evidence, causes, and consequences of a global decline in ecosystem nitrogen availability in terrestrial ecosystems
|MASON, RACHEL - National Socio-Environmental Synthesis Center|
|ELMORE, ANDREW - University Of Maryland|
|FULWEILER, ROBINSON - Boston University|
|GROFFMAN, PETER - City University Of New York|
|CRAINE, JOSEPH - Jonah Ventures Llc|
|LANY, NINA - Us Forest Service (FS)|
|JONARD, MATHIEU - Universite Catholique|
|OLLINGER, SCOTT - University Of New Hampshire|
|READ, QUENTIN - National Socio-Environmental Synthesis Center|
|REICH, PETER - University Of Minnesota|
|TEMPLER, PAMELA - Boston University|
Submitted to: Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/10/2022
Publication Date: 4/15/2022
Citation: Mason, R., Elmore, A., Fulweiler, R.W., Groffman, P., Craine, J., Lany, N., Jonard, M., Ollinger, S., Angerer, J.P., Read, Q., Reich, P.B., Templer, P.H. 2022. Evidence, causes, and consequences of a global decline in ecosystem nitrogen availability in terrestrial ecosystems. Science. 376(6590). https://doi.org/10.1126/science.abh3767.
Interpretive Summary: Although global supplies of nitrogen have more than doubled in the last century due to industrial and agricultural activities, recent studies have reported declines in nitrogen availability in many areas of the world. Nitrogen inputs are not evenly distributed across the planet, and in many locations, global increases in carbon dioxide and rising temperatures are increasing plant demand for nitrogen and may be reducing its supply. For areas experiencing a decline in nitrogen availability, this can lead to lower plant productivity, lower plant nitrogen content, and lower quality forage for herbivores, including livestock, wildlife, and insects. We have examined the current state of knowledge about declining nitrogen availability and the factors that could be causing it and offer ways to respond to these declines. Measures could include strengthening efforts to reduce carbon dioxide emissions, managing nitrogen retention in areas exhibiting declines, strategic and judicious introductions of nitrogen through supplemental feeding or fertilization, along with improving our ability to monitor and assess nitrogen conditions to inform adaptive management and decision making.
Technical Abstract: The productivity of ecosystems and their capacity to support life depends on access to reactive nitrogen (N). Over the last century, humans have more than doubled the global supply of reactive N through industrial and agricultural activities. However, long-term records demonstrate that N availability is declining in many regions of the world. Reactive N inputs are not evenly distributed, and global changes including elevated atmospheric CO2 and rising temperatures are affecting ecosystem N supply and demand. Declining N availability is contributing to lower leaf N concentrations, constraining primary productivity, and reducing the quality of herbivore diets. In this review we outline the current state of knowledge about declining N availability, and propose actions aimed at further characterizing and responding to this emerging challenge.