Cascading effects of earthworm invasion in tundra increase graminoid density and rodent grazing intensities

Earthworms are being introduced to numerous ecosystems through human activities. Some non-native earthworm species have the potential to ‘geoengineer’ soils and increase plant nitrogen (N) uptake, but if the increased plant N concentrations can cause increased rodent grazing is not well known. In this study, we present findings from a common garden experiment with two tundra communities, meadow (forb dominated) and heath (shrub dominated), half of them subjected to four years of earthworm presence (Lumbricus spp. and Aporrectodea spp.). Within four summers, our earthworm treatment changed plant community composition by increasing graminoid density by on average 94 % in the heath vegetation and by 49 % in the meadow. Rodent winter grazing were more intense on plants growing in soils with earthworms, an effect that coincided with higher nitrogen concentrations in plants indicating a higher palatability. Moreover, although the earthworms decreased soil moisture, our proxy for plant communi..., , , # Cascading effects of earthworm invasion in tundra increase graminoid density and rodent grazing intensities

[https://doi.org/10.5061/dryad.zpc866tbm](https://doi.org/10.5061/dryad.zpc866tbm)

The data set is from a common garden mesocosm experiment in Abisko, sub-Arctic Sweden running between 2017-2020.
More information about each variable is provided in the manuscript methods.

## Description of the data and file structure

**File ‘Data.xlsx’**

Contains variables:
*Variables of Mesocosm_properties:*
“Plot_nr” = Number ID of each mesocosm
“Block_nr” = Number ID of the sand beds in which the mesocosm monoliths were placed.
“Treatment” = Worm /No worm whether the mesocosm plot had earthworm treatment or not
“Vegetationtype” = Mesocosm vegetation type (Heath or Meadow)

*Variables from Vegetation inventory 2020 [hits/pin]:*
“FORBS” = Pin intercept inventory of vegetation functional groups, the number of forb hits per pin for each mesocosm.
“GRAMINOIDS” = Pin intercept inventory of vege...

人类活动正将蚯蚓引入全球众多生态系统。部分非本土蚯蚓物种具备对土壤开展地质工程改造（geoengineering）的潜力，同时可提升植物对氮（N）的吸收效率，但植物氮浓度升高是否会导致啮齿动物取食强度增加，目前尚无定论。本研究基于两项苔原群落的同质园实验（common garden experiment）展开分析，实验群落分别为草甸（以杂类草为主）与灌丛苔原（以灌木为主），其中一半样地经过四年的蚯蚓接种处理（所用蚯蚓为正蚓属（Lumbricus spp.）与寒蚓属（Aporrectodea spp.）物种）。在四年的实验周期内，蚯蚓处理组改变了植物群落组成：灌丛苔原的禾本科植物密度平均提升94%，草甸群落的禾本科植物密度平均提升49%。生长在施加过蚯蚓的土壤中的植物，其冬季啮齿动物取食强度更高；这一现象与植物体内氮浓度升高相吻合，表明此类植物的适口性更佳。此外，尽管蚯蚓接种降低了土壤含水量——本研究中土壤含水量为植物群落的替代指标……
# 苔原蚯蚓入侵的级联效应：提升禾本科植物密度与啮齿动物取食强度
[https://doi.org/10.5061/dryad.zpc866tbm](https://doi.org/10.5061/dryad.zpc866tbm)

本数据集来源于瑞典亚北极地区阿比斯库（Abisko）的中宇宙实验（mesocosm experiment），实验周期为2017年至2020年。各变量的详细说明可参见论文的方法部分。

## 数据与文件结构说明
**文件‘Data.xlsx’**
包含以下变量：
*中宇宙实验样地属性变量：*
"Plot_nr"：每个中宇宙实验样地的编号ID
"Block_nr"：放置中宇宙实验原状土柱的沙床编号ID
"Treatment"：蚯蚓处理分组，分为施加蚯蚓组（Worm）与对照组（No worm）
"Vegetationtype"：中宇宙实验样地的植被类型（灌丛苔原或草甸）

*2020年植被调查变量 [每针接触数（hits/pin）]:*
"FORBS"：植被功能群的针插式调查结果，指每个中宇宙样地每根针接触到杂类草的次数
"GRAMINOIDS"：植被功能群的针插式调查结果……