DOI: 10.5061/dryad.4mw6m90p5
title: Species turnover and climates co-dominate the carbon–water relationship in grasslands along an elevational gradient

description: Water use efficiency (WUE) serves as a core function reflecting
 vegetation-climate interactions and terrestrial carbon-water cycle.
 However, direct measurements of WUE are largely constrained to indoor
 experiments, individual plant, and instantaneous physiological reaction,
 and neglect the effects of long-term climate change and species
 composition of natural ecosystems. Here, we built an elevational gradient
 (40-3800m), which can be viewed as an open-air laboratory for studying
 plant physiological responses to climate change and species adaptation,
 and we conducted an intensive field survey (98 sites) and collected
 datasets (plants, climates, soils) to investigate the geospatial of
 instinct water use efficiency (iWUE) of grasslands and its potential
 drivers. We found an uptrend and downtrend in iWUE for C3 and C4 herbs in
 grasslands with the rising elevation, respectively. Those patterns of iWUE
 primarily driven by variations in microclimatic factors (e.g,.
 temperature, vapor pressure deficit), species turnover, and plant
 stoichiometry rather than species richness. These results challenge the
 prevailing climate-centric paradigm in WUE studies, highlighting the
 critical role of species turnover and nutrient allocation strategies with
 environmental change. Our results revealed the integrated interactions
 between species composition and climates could more precisely predict
 shifts in WUE, thereby providing empirical evidence to strengthen in-depth
 understanding of carbon-water cycles under future climate change.
description: # Species turnover and climates co-dominate the carbon–water relationship
 in grasslands along an elevational gradient Dataset DOI:
 [10.5061/dryad.4mw6m90p5](10.5061/dryad.4mw6m90p5) ## Description of the
 data and file structure Based on an intensive field survey (98 sites)
 along an elevational gradient in Southwest China, we collected a dataset
 of 207 samples, including plants, climates, and soils, to investigate the
 geospatial distribution of intrinsic water use efficiency (iWUE) and
 isotopic evidence from grasslands and its potential drivers. ### Files and
 variables | Variables | Detailed Description | Units | | :-------- |
 :------------------------------------------------------------------------
 | :--------- | | sites | sites name | unitless | | plot | plot ID |
 unitless | | spe\_en | species  latinname  | unitless | | region | sample
 region YN:yunan provinve, GX:Guangxi province | unitless | | class | plant
 type,C3 plant,C4 plant | unitless | | lat | lattitude | unitless | | lon |
 longitude | unitless | | alt | elevation | m | | mat | mean annual
 temprature | ℃ | | map | mean annual precipitation | mm | | ai | aridity
 index | unitless | | pet | potential evapotranspiration | mm·yr-1 | | vpd
 | vapor pressure defict | kPa | | shannon | shannon diversity index |
 unitless | | simpson | simpson diversity index | unitless | | species |
 species richness | unitless | | C | leaf carbon concentration | g·kg-1 | |
 N | leaf nitrogen concentration | g·kg-1 | | P | leaf phosphorus
 concentration | g·kg-1 | | C\_N | leaf carbon-nitrogen ratio | unitless |
 | C\_P | leaf carbon-phosphorus ratio | unitless | | N\_P | leaf
 nitrogen-phosphorus ratio | unitless | | δ13C | leaf carbon isotope | ‰ |
 | DTC | cabon isotopic discrimination relative to the source | ‰ | | Ci/Ca
 | the ratio of partial pressures of CO2 in the atmosphere and
 intercellular | unitless | | WUE | intrinsic water use efficiency |
 μmol·mol-1 | | stp | soil total phosphorus concentration | g·kg-1 | | soc
 | soil organic carbon | g·kg-1 | | stn | soil total nitrogen | g·kg-1 | |
 scn | soil carbon nitrogen ratio | unitless | ## Access information Data
 was derived from the following sources: * Data deposited in the Dryad
 Digital Repository:
 [https://doi.org/10.5061/dryad.4mw6m90p5](https://doi.org/10.5061/dryad.4mw6m90p5) (Bai* et al.* 2025)