caa a22 4500 445384174 CHVBK 20180317143026.0 cr unu---uuuuu 170323e20110801xx s 000 0 eng 10.1007/s10021-011-9450-x doi (NATIONALLICENCE)springer-10.1007/s10021-011-9450-x Hot Spots of Inorganic Nitrogen Availability in an Alpine-Subalpine Ecosystem, Colorado Front Range [Elektronische Daten] [Anthony Darrouzet-Nardi, William. Bowman] Inorganic nitrogen (N) availability hot spots have been documented in many ecosystems, but major uncertainties remain about their prevalence, timing, and causes. Using a novel mathematical definition of hot spots, spatially explicit measurements of KCl-extractable inorganic N, 2-week soil incubations in the field, ion-exchange resins deployed for 1year, and a set of associated biotic and abiotic variables, we investigated inorganic N availability hot spots within a 0.89km2 alpine-subalpine ecosystem in the Colorado Front Range. Measurements of KCl-extractable NH4 + and NO3 − taken on multiple dates showed that hot spots of N availability were present in some but not all parts of the study site and that hot spot location varied over the course of the season. Ion-exchange resins showed that over a 1-year period hot spots were important contributors to resin-available N at the landscape level, with 14% of resin locations accounting for 58% of total resin-extractable inorganic N. The KCl-extractable and resin-available inorganic N measurements showed that although spatial variation in the timing of hot spots (that is, hot moments) spreads the influence of short-term hot spots across the landscape to some extent, spatial variation in inorganic N availability is still important when integrated over 1year. Resin-available N was poorly correlated with the biotic and abiotic variables that we measured, though we did observe that hot spots of resin-available N were twice as common below tree and shrub canopies than in herbaceous areas. Beyond this relationship with canopy structure, neither KCl-extractable nor resin-available inorganic N hot spots were closely related to plant species identity. Instead, the most effective predictor of KCl-extractable NH4 + was the size of the soil organic matter (SOM) N pool, with nearly all hot spots appearing in soils that had greater than 1.4% SOM N. Springer Science+Business Media, LLC, 2011 nutrient availability nationallicence Lorenz curve nationallicence spatially explicit nationallicence inequality nationallicence Niwot Ridge LTER nationallicence random forest model nationallicence disproportion nationallicence Darrouzet-Nardi Anthony Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, N122 Ramaley, 334 UCB, 80309-0334, Boulder, Colorado, USA aut Bowman William Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, N122 Ramaley, 334 UCB, 80309-0334, Boulder, Colorado, USA aut Ecosystems Springer-Verlag 14/5(2011-08-01), 848-863 1432-9840 14:5<848 2011 14 10021 https://doi.org/10.1007/s10021-011-9450-x text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10021-011-9450-x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Darrouzet-Nardi Anthony Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, N122 Ramaley, 334 UCB, 80309-0334, Boulder, Colorado, USA aut NATIONALLICENCE 700 1- Bowman William Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, N122 Ramaley, 334 UCB, 80309-0334, Boulder, Colorado, USA aut NATIONALLICENCE 773 0- Ecosystems Springer-Verlag 14/5(2011-08-01), 848-863 1432-9840 14:5<848 2011 14 10021 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer