TY - JOUR
AU1 - Rao, Leela E.
AU2 - Allen, Edith B.
AB - Primary production in deserts is limited by soil moisture and N availability, and thus is likely to be influenced by both anthropogenic N deposition and precipitation regimes altered as a consequence of climate change. Invasive annual grasses are particularly responsive to increases in N and water availabilities, which may result in competition with native forb communities. Additionally, conditions favoring increased invasive grass production in arid and semi-arid regions can increase fire risk, negatively impacting woody vegetation that is not adapted to fire. We conducted a seeded garden experiment and a 5-year field fertilization experiment to investigate how winter annual production is altered by increasing N supply under a range of water availabilities. The greatest production of invasive grasses and native forbs in the garden experiment occurred under the highest soil N (inorganic N after fertilization = 2.99 g m−2) and highest watering regime, indicating these species are limited by both water and N. A classification and regression tree (CART) analysis on the multi-year field fertilization study showed that winter annual biomass was primarily limited by November–December precipitation. Biomass exceeded the threshold capable of carrying fire when inorganic soil N availability was at least 3.2 g m−2 in piñon-juniper woodland. Due to water limitation in creosote bush scrub, biomass exceeded the fire threshold only under very wet conditions regardless of soil N status. The CART analyses also revealed that percent cover of invasive grasses and native forbs is primarily dependent on the timing and amount of precipitation and secondarily dependent on soil N and site-specific characteristics. In total, our results indicate that areas of high N deposition will be susceptible to grass invasion, particularly in wet years, potentially reducing native species cover and increasing the risk of fire.Electronic supplementary materialThe online version of this article (doi:10.1007/s00442-009-1516-5) contains supplementary material, which is available to authorized users.
TI - Combined effects of precipitation and nitrogen deposition on native and invasive winter annual production in California deserts
JF - Oecologia
DO - 10.1007/s00442-009-1516-5
DA - 2009-12-05
UR - https://www.deepdyve.com/lp/pubmed-central/combined-effects-of-precipitation-and-nitrogen-deposition-on-native-YM80Ts9rjs
SP - 1035
EP - 1046
VL - 162
IS - 4
DP - DeepDyve
ER -