caa a22 4500 605516677 CHVBK 20210128100715.0 cr unu---uuuuu 210128e20150501xx s 000 0 eng 10.1007/s10533-015-0090-7 doi (NATIONALLICENCE)springer-10.1007/s10533-015-0090-7 Shifting soil resource limitations and ecosystem retrogression across a three million year semi-arid substrate age gradient [Elektronische Daten] [Gregory Newman, Stephen Hart] The current paradigm of plant nutrient limitation during ecosystem development predicts a change from nitrogen (N) limitation when substrates are young to phosphorus (P) limitation when substrates are old. However, there are surprisingly few direct tests of this model. We evaluated this theory experimentally along a three million year semi-arid substrate age gradient using resource additions to intercanopy spaces dominated by the C4 bunchgrass Bouteloua gracilis. Unlike other gradients in subtropical and temperate ecosystems, soil water availability also increases strongly across this semi-arid system due to finer texture with substrate age. We found that aboveground net primary production (ANPP) of B. gracilis was limited by both water and N on the 55ky substrate; not limited by N, P, or water on the 750ky substrate; and limited by P alone on the 3000ky substrate. Notably, measures of foliar nutrient concentration and N:P mass ratios were unable to predict nutrient limitations in these semi-arid systems. In unamended plots, mean ANPP declined dramatically at 3000ky compared to the younger substrate age sites, presumably due to progressive limitation by P. This decline in ANPP late in ecosystem development is consistent with a reduction in soil total carbon and N storage at this site and provides a mechanism for successional retrogression in ecosystem structure and function. Our results unify biogeochemical theory across disparate ecosystems while illustrating the important water-nutrient interactions in these semi-arid ecosystems to further define the nature of nutrient limitations in terrestrial ecosystems. Springer International Publishing Switzerland, 2015 Chronosequence nationallicence Nitrogen nationallicence N:P stoichiometry nationallicence Phosphorus nationallicence Piñon-juniper nationallicence Soil development nationallicence Newman Gregory School of Forestry, Northern Arizona University, Flagstaff, AZ, USA aut Hart Stephen School of Forestry, Northern Arizona University, Flagstaff, AZ, USA aut Biogeochemistry Springer International Publishing 124/1-3(2015-05-01), 177-186 0168-2563 124:1-3<177 2015 124 10533 https://doi.org/10.1007/s10533-015-0090-7 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10533-015-0090-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Newman Gregory School of Forestry, Northern Arizona University, Flagstaff, AZ, USA aut NATIONALLICENCE 700 1- Hart Stephen School of Forestry, Northern Arizona University, Flagstaff, AZ, USA aut NATIONALLICENCE 773 0- Biogeochemistry Springer International Publishing 124/1-3(2015-05-01), 177-186 0168-2563 124:1-3<177 2015 124 10533