DOI: 10.5061/dryad.prr4xgxtn
title: Plant biomass in three subalpine grasslands on Qinghai-Tibetan Plateau

description: Aims: Multiple studies have addressed the relationship between plant
 biomass and species richness, often reporting a hump-shaped curve.
 However, such research in natural grassland was mostly conducted in
 temperate, arid and semiarid areas, with few studies focused on alpine
 regions. Moreover, in most cases, plant community biomass was the main
 variable of interest, with few studies considering also plant individual
 biomass, calculated by dividing plant community biomass by plant
 abundance. Location: To explore the relationship between plant biomass and
 species richness in subalpine regions, a field survey was conducted in
 three locations with fenced subalpine grasslands on the Qinghai-Tibetan
 Plateau in China in 2020 and 2023. Methods: Plant aboveground biomass and
 species richness were recorded along four transects in each location.
 Analyses were performed using both plant community biomass and plant
 individual biomass to test whether using a different biomass measure
 affected the plant biomass-species richness relationship. Results:
 Location and year × location significantly affected species richness,
 plant community biomass and plant individual biomass. Curve estimations
 demonstrated a positive nonlinear relationship between plant community
 biomass and species richness, and a negative nonlinear relationship
 between plant individual biomass and species richness. These patterns were
 modified by the locations of the three grasslands. Competition can explain
 some of the different patterns between plant community biomass-species
 richness relationship and plant individual biomass-species richness
 relationship. Conclusions: In general, the choice of biomass approach
 affected the relationship between plant biomass and species richness in
 subalpine grasslands, which indicates that plant abundance impacts plant
 biomass-species richness relationship. Future research should consider
 further modulators and drivers when exploring the plant biomass-species
 richness relationship in grasslands in a climate change context.
description: Transect sampling is assumed to be an effective method to
 incorporate variation between grassland communities. Accordingly, four
 transects were randomly set in each location. All transects had a length
 of 105 m, and quadrats with a size of 0.5 m × 0.5 m were laid out at 0, 5,
 15, 30, 50, 75, and 105 m along each transect, with the quadrat size
 matching previous studies conducted in these locations. In each quadrat,
 species richness was quantified (i.e. the total number of different
 species), plant abundance (i.e. plant density in this case) was measured
 by counting the total individual number of each species, and dry biomass
 was determined after harvesting all plants in each quadrat and oven drying
 at 105 °C for 48 hours.
description: # Plant biomass in three subalpine grasslands on Qinghai-Tibetan Plateau
 [https://doi.org/10.5061/dryad.prr4xgxtn](https://doi.org/10.5061/dryad.prr4xgxtn) ## Description of the data and file structure A description of the dataset can be found as follows: the letters in the dataset are explained, and Y refers to the year that collected the data. Locations of HY, MQ and DR refer to the three locations of the grasslands involved in this study, and they are Hongyuan, Maqu and Dari, respectively. Biomass1 refers to the plant community biomass, and biomass2 refers to the plant individual biomass. Moreover, the meaning of evenness, richness and density can be found from the description of the method in this study: Four transects were randomly set in each location. All transects had a length of 105 m, and 7 quadrats with a size of 0.5 m × 0.5 m were laid out at 0, 5, 15, 30, 50, 75, and 105 m along each transect to allow better (future) comparisons to other studies in this area. The quadrat size matched previous studies conducted in these locations . In each quadrat, species richness was quantified (i.e. the total number of different species) and plant abundance (i.e. plant density in this case) was measured by counting the total individual number of each species. Because some species in our study (notably Potentilla anserina and Kobresia humilis) are clonal, it was not always possible to distinguish individual plants. This is why we counted the ramets of clonal species, in line with previous studies. This therefore does not allow studying effects of intra-clonal facilitation in clonal species on the relationship of plant biomass and species richness, which could be addressed in more targeted future research. Finally, dry biomass was determined after harvesting all plants in each quadrat and oven drying at 105 °C for 48 hours. The aims of this study: Multiple studies have addressed the relationship between plant biomass and species richness, often reporting a hump-shaped curve. However, such research in natural grassland was mostly conducted in temperate, arid and semi-arid areas, with few studies focused on sub-alpine regions. Moreover, in most cases, plant community biomass was the main variable of interest, with few studies considering also plant individual biomass, calculated by dividing plant community biomass by plant abundance. To explore the relationship between plant biomass and species richness in sub-alpine regions, a field survey was conducted in three locations with fenced sub-alpine grasslands on the Qinghai-Tibetan Plateau in China in 2020 and 2023. Plant aboveground biomass and species richness were recorded along four transects in each location. Analyses were performed using both plant community biomass and plant individual biomass to test whether using a different biomass measure affected the plant biomass-species richness relationship. ### Files and variables #### File: Dataset.xlsx **Description:**  Four transects were randomly set in each location. All transects had a length of 105 m, and 7 quadrats with a size of 0.5 m × 0.5 m were laid out at 0, 5, 15, 30, 50, 75, and 105 m along each transect to allow better (future) comparisons to other studies in this area. The quadrat size matched previous studies conducted in these locations . In each quadrat, species richness was quantified (i.e. the total number of different species) and plant abundance (i.e. plant density in this case) was measured by counting the total individual number of each species. Because some species in our study (notably Potentilla anserina and Kobresia humilis) are clonal, it was not always possible to distinguish individual plants. This is why we counted the ramets of clonal species, in line with previous studies. This therefore does not allow studying effects of intra-clonal facilitation in clonal species on the relationship of plant biomass and species richness, which could be addressed in more targeted future research. Finally, dry biomass was determined after harvesting all plants in each quadrat and oven drying at 105 °C for 48 hours. ##### Variables * the letters in the dataset are explained, and Y refers to the year that collected the data. Locations of HY, MQ and DR refer to the three locations of the grasslands involved in this study, and they are Hongyuan, Maqu and Dari, respectively. Biomass1 refers to the plant community biomass, and biomass2 refers to the plant individual biomass. Moreover, the meaning of evenness, richness and density can be found from the description of the method in this study: ## Code/software All the analyses were conducted with SPSS 21.0.