Abstract
Tree and shrub planting is a widely used strategy to restore degraded semi-arid grasslands. Although nutrient resorption is a key adaptation to nutrient-limited environments, its dynamics at decadal scales remain poorly understood. In this study, we measured species-averaged nitrogen resorption efficiency (NRE) at both community and functional group levels, together with soil nutrients, across 20- and 40-year shrub-planted sites and a 40-year tree-planted site in Inner Mongolia, China. At the community level, green and senesced leaf nitrogen (N) concentrations, NRE, and aboveground biomass did not differ significantly among sites. However, clear differences emerged at the functional group level: Poaceae exhibited higher NRE than forbs and lower senesced leaf N than both forbs and Fabaceae. As restoration progressed, Poaceae replaced forbs as the dominant group, coinciding with increased soil nutrient availability. Notably, NRE in Poaceae declined with increasing soil nutrients, suggesting a shift toward greater reliance on direct soil nutrient uptake. This shift, combined with the production of low-nitrogen litter by dominant Poaceae species, may ultimately slow soil nutrient accumulation. Our findings highlight the importance of functional group dynamics in regulating long-term nutrient resorption and cycling and suggest that managing Poaceae dominance could enhance long-term soil nutrient enrichment and biodiversity in restored semi-arid grasslands.
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Claims 12
Claim · model-written summary
Community green leaf nitrogen concentration did not differ significantly among restoration sites.
Not reportedTaxon
Verbatim
e0“At the community level, green and senesced leaf nitrogen (N) concentrations, NRE, and aboveground biomass did not differ significantly among sites”
Claim · model-written summary
Community senesced leaf nitrogen concentration did not differ significantly among sites.
Not reportedTaxon
Verbatim
e0“At the community level, green and senesced leaf nitrogen (N) concentrations, NRE, and aboveground biomass did not differ significantly among sites”
Claim · model-written summary
Community nitrogen resorption efficiency did not differ significantly among sites.
Not reportedTaxon
Verbatim
e0“At the community level, green and senesced leaf nitrogen (N) concentrations, NRE, and aboveground biomass did not differ significantly among sites”
Claim · model-written summary
Community aboveground biomass did not differ significantly among sites.
Not reportedTaxon
Verbatim
e0“At the community level, green and senesced leaf nitrogen (N) concentrations, NRE, and aboveground biomass did not differ significantly among sites”
Claim · model-written summary
Poaceae had higher nitrogen resorption efficiency than forbs.
Verbatim
e0“Poaceae exhibited higher NRE than forbs and lower senesced leaf N than both forbs and Fabaceae”
Claim · model-written summary
Poaceae had lower senesced-leaf nitrogen than forbs and Fabaceae.
Verbatim
e0“Poaceae exhibited higher NRE than forbs and lower senesced leaf N than both forbs and Fabaceae”
Claim · model-written summary
Poaceae replaced forbs as the dominant group during restoration.
Not reportedDirection
Verbatim
e0“As restoration progressed, Poaceae replaced forbs as the dominant group, coinciding with increased soil nutrient availability”
Claim · model-written summary
Soil nutrient availability increased as restoration progressed.
Not reportedTaxon
Verbatim
e0“As restoration progressed, Poaceae replaced forbs as the dominant group, coinciding with increased soil nutrient availability”
Claim · model-written summary
Poaceae nitrogen resorption efficiency declined with increasing soil nutrients.
Not reportedCompound
Verbatim
e0“NRE in Poaceae declined with increasing soil nutrients”
Claim · model-written summary
The authors suggest greater reliance on direct soil nutrient uptake as Poaceae nitrogen resorption declines.
Verbatim
e0“NRE in Poaceae declined with increasing soil nutrients, suggesting a shift toward greater reliance on direct soil nutrient uptake”
Claim · model-written summary
The authors suggest that Poaceae low-nitrogen litter and nutrient uptake may slow soil nutrient accumulation.
Verbatim
e0“This shift, combined with the production of low-nitrogen litter by dominant Poaceae species, may ultimately slow soil nutrient accumulation”
Claim · model-written summary
The authors suggest managing Poaceae dominance to improve nutrient enrichment and biodiversity in restored grasslands.
Verbatim
e0“managing Poaceae dominance could enhance long-term soil nutrient enrichment and biodiversity in restored semi-arid grasslands”