Convergoing responses of nutrient resorption in plant life forms to nitrogen addition in temperate shrublands: Dataset

Atmospheric nitrogen (N) deposition has significantly altered nutrient availability in most terrestrial ecosystems, which may affect plant nutrient resorption and hence change community composition and nutrient cycling. Nutrient resorption from senesced leaves is a ubiquitous mechanism of nutrient conservation, which is very important for plants to adapt to nutrient deficiency. However, how N deposition affects leaf concentration and internal nutrient cycling of different life forms remains unclear, especially in temperate shrublands. A 4-year N addition manipulation experiment in Vitex negundo and Spiraea trilobata shrublands was conducted, and the green and senesced leaf N ([N]g and [N]s) and phosphorus ([P]g and [P]s ) concentrations and N (NRE) and P (PRE) resorption efficiency of two plant life forms were investigated. We found that both NRE and PRE varied markedly between the two life forms, being lower in shrubs and higher in graminoids, implying that shrubs probably have a higher capability of acquiring nutrients from soil, whereas graminoids rely on acquiring more nutrients via resorption. N addition increased the [N]g, [N]s and N:P ratios ([N:P]) of shrubs and all species, whereas it had negligible effects on graminoids. The [P]g and [P]s, NRE and PRE did not change in either life form or all species combined after N fertilization. Our results suggest that shrubs increase N uptake but do not alter internal N cycling, whereas graminoids do not change N acquisition strategies, in response to increased N supply from the soil. Continuous N addition exacerbated the P limitation of the shrub plants. Both shrubs and graminoids were more likely to adopt nearly complete utilization of P from the soil and senesced leaves under P deficiency, leading to a noneffect of N addition on leaf PRE.