Title | Nitrogen limitation in arid-subhumid ecosystems: A meta-analysis of fertilization studies |
Publication Type | Journal Article |
Year of Publication | 2011 |
Authors | Yahdjian L, Gherardi LA, Sala O.E |
Journal | Journal of Arid Environments |
Volume | 75 |
Issue | 8 |
Pagination | 675-680 |
Accession Number | JRN00579 |
Keywords | arid ecosystems, article, journal, meta-analysis, nitrogen fertilization, primary production, resource limitation |
Abstract | Evidence supporting water limitation in arid-semiarid ecosystems includes strong correlations between aboveground net primary production (ANPP) and annual precipitation as well as results from experimental water additions. Similarly, there is evidence of N limitation on ANPP in low precipitation ecosystems, but is this a widespread phenomenon? Are all arid-semiarid ecosystems equally limited by nitrogen? Is the response of N fertilization modulated by water availability? We conducted a meta-analysis of ANPP responses to N fertilization across arid to subhumid ecosystems to quantify N limitation, using the effect-size index R which is the ratio of ANPP in fertilized to control plots. Nitrogen addition increased ANPP across all studies by an average of 50%, and nitrogen effects increased significantly (P = 0.03) along the 50–650 mm yr−1 precipitation gradient. The response ratio decreased with mean annual temperature in arid and semiarid ecosystems but was insensitive in subhumid systems. Sown pastures showed significant (P = 0.007) higher responses than natural ecosystems. Neither plant-life form nor chemical form of the applied fertilizer showed significant effects on the primary production response to N addition. Our results showed that nitrogen limitation is a widespread phenomenon in low-precipitation ecosystems and that its importance increases with annual precipitation from arid to subhumid regions. Both water and N availability limit primary production, probably at different times during the year; with frequency of N limitation increasing and frequency of water limitation decreasing as annual precipitation increases. Expected increase N deposition, which could be significant even in arid ecosystems, would increase aboveground net primary production in water-limited ecosystems that account for 40% of the terrestrial surface. |
URL | files/bibliography/JRN00579.pdf |
DOI | 10.1016/j.jaridenv.2011.03.003 |