DOI: 10.5061/dryad.31zcrjf1d
title: Plant defense trait responses to grazing along an aridity gradient in Inner Mongolian grasslands

description: Silicon (Si) and phenolics are vital players in the plant kingdom,
 enabling plants to combat both biotic stresses, like herbivory, and
 abiotic challenges, such as drought. Yet, the interplay between
 community-level silica and phenolic defenses in response to livestock
 grazing and climatic factors across large spatial scales remains
 underexplored. We analyzed the Si and phenolic concentrations of plant
 communities from 15 widely distributed sites, strategically selected along
 a 1700 km aridity gradient in the temperate grasslands of northern China,
 with livestock grazing manipulated (grazed vs. ungrazed) at each location.
 Our findings revealed that grazing significantly enhanced community-level
 silica-based defenses in less arid grasslands, mainly due to increased
 intraspecific Si concentration, while its impact on phenol-based defenses
 was minimal. Notably, as aridity increased, Si concentration surged while
 phenolic concentration dwindled, indicating a shift from phenol- to
 silica-based defenses in drier environments. In ungrazed grasslands,
 silica and phenolic defenses were negatively correlated, a relationship
 that vanished in grazed treatment. Further analysis revealed that Si
 concentration was primarily influenced by grazing management, while
 phenolic concentration was mainly associated with aridity. Our study
 provides the community-level and regional-scale assessment of how grazing
 management impacts plant silica- and phenol-based defenses along an
 aridity gradient in the temperate grasslands. Together, our results showed
 that plants accumulated Si but not phenolics as a defense mechanism in
 response to decades of livestock grazing. Importantly, our findings
 suggested that grazing disrupted the trade-off between the two plant
 defense strategies along the aridity gradient. These insights emphasize
 the critical role of grazing management and aridity in shaping silica and
 phenolic defenses, revealing a complex interplay between environmental
 conditions and plant defense strategies in grassland ecosystems.
description: # **README for Dataset: Plant defense Trait Responses to Grazing along an
 aridity gradient in Inner Mongolian Grasslands** **Dataset:**
 data_defense_traits.xlsx **Related Manuscript:** Grazing disrupts the
 trade-off between silica- and phenol-based plant defenses along an aridity
 gradient in grasslands **Authors:** Kaicun Yan, Wen Xia, Ketao Yu, Xiaoyu
 Yang, Xiaomin Wang, Jianmin Wang, Yi Zhou, Xin Jing, Haiyang Zhang, Yong
 Jiang, Xingguo Han, Lingfei Yu **Correspondence:** Lingfei Yu
 **Repository:** Dryad Digital Repository **1. Overview** This dataset
 accompanies the manuscript titled “Grazing disrupts the trade-off between
 silica- and phenol-based plant defenses along an aridity gradient in
 grasslands” (submitted to *Functional Ecology*). Data were collected from
 a field study across a natural aridity gradient in the grasslands of Inner
 Mongolia, China. The study used a paired design of grazing exclusion
 (fenced) versus grazing to examine how aridity and grazing interact to
 affect plant defensive traits (silicon and phenolics). The dataset
 includes two files: ·        **Plant community-level data**: Plant
 community and soil variables across sites and treatments. ·       
 **Leaf-level data**: Leaf defensive traits of species common to both
 grazing treatments. **2. Data Collection Methods** ·        **Site
 Selection**: 15 sites were established along a natural aridity gradient in
 Inner Mongolia. ·        **Experimental Design**: Each site contained
 paired plots: Ungrazed: Plots protected from livestock grazing. Grazed:
 Plots under ongoing livestock grazing. ·        **Plant Community
 Sampling**: Aboveground biomass was harvested by species. Soil samples
 were collected for nutrient and property analysis. ·        **Leaf Trait
 Sampling**: Leaves from species present in both grazing treatments at each
 site were sampled and analyzed for defensive traits (silicon, phenolics).
 ·        **Climate Data**: Aridity Index were derived from the Global
 Aridity Index Database v2. Mean Annual Precipitation (MAP) and Mean Annual
 Temperature (MAT) were obtained for each site from the China
 Meteorological Data Service Center
 ([http://data.cma.cn/en)](http://data.cma.cn/en\)). **3. File
 Descriptions** **·        Sheet: Community_Data** **Description**:
 Contains plant community biomass, soil properties, and site-level climate
 variables. **Key Variables**: §  Site, Treatment, Age (fence
 age), Vegetation_type §  Phenolics, Si, C, N, P (leaf traits from
 community-level samples) § 
 Forb_biomass, Grass_biomass, Biomass (community biomass) § 
 Soil_N, Soil_P, Soil_available_Si, Soil_pH, SWC (soil properties) § 
 Aridity, MAP, MAT (climate variables) **·        Sheet: Leaf_Data**
 **Description**: Contains species-specific leaf traits from samples
 collected in both grazing treatments. **Key Variables**: § 
 Site, Treatment, Vegetation_type, Sample_id §  Species, Functional group
 §  Leaf Si, Leaf phenolics (defensive traits) **4. Data Dictionary** **4.1
 Sheet: Community_Data** | **Column Name** | **Unit / Format** |
 **Description** | | :---------------------- | :---------------- |
 :------------------------------------------------------------- | |
 **Site** | Text | Unique identifier for each sampling location. | |
 **Treatment** | Text | Grassland management: Ungrazed (grazing exclusion)
 or Grazed. | | **Age** | Years (yr) | Age of the grazing exclusion
 fence. 0  for grazed plots. | | **Vegetation\_type** | Text | Dominant
 grassland type (e.g., Typical Steppe, Desert Steppe). | | **Sample\_id** |
 Text | Unique identifier for each sample. | | **Phenolics** | g kg⁻¹ |
 Plant community-level phenolic concentration. | | **Si** | g kg⁻¹ | Plant
 community-level silicon concentration. | | **C** | % | Plant
 community-level carbon concentration. | | **N** | % | Plant
 community-level nitrogen concentration. | | **P** | g kg⁻¹ | Plant
 community-level phosphorus concentration. | | **Forb\_biomass** | g m⁻² |
 Aboveground biomass of forbs. | | **Grass\_biomass** | g m⁻² | Aboveground
 biomass of grasses. | | **Biomass** | g m⁻² | Total aboveground plant
 community biomass. | | **Soil\_N** | g kg⁻¹ | Total soil nitrogen
 concentration. | | **Soil\_P** | g kg⁻¹ | Total soil phosphorus
 concentration. | | **Soil\_available\_Si** | mg kg⁻¹ | Bioavailable
 silicon concentration in soil. | | **Soil\_pH** | - | Soil pH measured in
 a soil-water solution. | | **SWC** | % | Soil Water Content. | |
 **Aridity** | Unitless | Aridity Index for the site. | | **MAP** | mm |
 Mean Annual Precipitation. | | **MAT** | °C | Mean Annual Temperature. |
 **4.2 Sheet: Leaf_Data** | **Column Name** | **Unit / Format** |
 **Description** | | :------------------- | :---------------- |
 :------------------------------------------------------------------ | |
 **Site** | Text | Unique identifier for each sampling location. | |
 **Treatment** | Text | Grassland management: Ungrazed or Grazed. | |
 **Vegetation\_type** | Text | Dominant grassland type. | | **Sample\_id**
 | Text | Unique identifier for each sample. | | **Species** | Text |
 Scientific name of the sampled species. | | **Functional group** | Text |
 Plant functional group (e.g., Grass, Forb). | | **Leaf Si** | g kg⁻¹ |
 Silicon concentration in leaf tissue of the sampled species. | | **Leaf
 phenolics** | g kg⁻¹ | Total phenolic concentration in leaf tissue of the
 sampled species. | **5. Usage Notes** ·        Missing data are
 represented as NA. ·        All chemical analyses were performed using
 standard laboratory protocols detailed in the associated manuscript.
 ·        The two files can be linked via Site and Treatment for integrated
 analyses. ·        Leaf trait data include only species that were present
 in both grazing treatments at each site, enabling direct comparisons of
 intraspecific trait variation.