Soil disturbance cover data on 1m x 1m plots from the long-term Small Mammal Exclusion Study (SMES) at Jornada Basin LTER, 1995-2020

This data package contains soil disturbance data from plots with
various levels of herbivore exclusion on the Jornada Experimental
Range. Study sites were established in 1995; one in black grama
grassland and the other in creosotebush shrubland to compare the
impact of herbivores on ecosystem processes between these vegetation
types. Parallel studies were established at the Sevilleta LTER site
(New Mexico, USA) and Mapimi Biosphere Reserve (Durango, Mexico).
Each study site is 1 km by 0.5 km in area. Four replicate
experimental blocks were randomly located at the grassland study
site to measure vegetation responses using exclusion treatments
including a) all mammalian herbivores, including cattle, lagomorphs,
and rodents, b) lagomorphs and cattle only, c) cattle only, and d)
control accessible to all herbivores. Because grazing cattle are
excluded from the entire creosote site, only three replicate
experimental blocks were randomly located there including a) all
mammalian herbivores, including lagomorphs, and rodents, b)
lagomorphs only, and c) control accessible to all herbivores.
Thirty-six sampling points were positioned at 5.8-meter intervals on
a systematically located 6 by 6 point grid within each plot. A
permanent one-meter by one-meter vegetation measurement quadrat is
located at each of the 36 points. Each year in spring and fall from
1995-2005, various forms of disturbances (human, rabbit, cow,
antelope, rodent, etc) were measured by depth . After 2005, sampling
frequency changed to every 5 years. This study is ongoing.

本数据包收录了赫罗纳实验牧场（Jornada Experimental Range）不同食草动物排除梯度样地的土壤扰动数据。研究于1995年设立两处核心样地，分别坐落于黑格兰马草草原与杂酚油灌丛（creosotebush shrubland），旨在对比两类植被类型下食草动物对生态系统过程的影响。美国新墨西哥州塞维利亚长期生态研究（Long-Term Ecological Research, LTER）站点，以及墨西哥杜兰戈州马皮米生物圈保护区，亦同步设立了平行对照研究。
各研究样地的面积均为1平方千米×0.5平方千米。黑格兰马草草原样地随机布设4个重复实验区，通过差异化食草动物排除处理测定植被响应，处理组包括：a) 全面排除所有哺乳动物食草动物，涵盖牛、兔形目动物与啮齿类；b) 仅保留兔形目动物与牛，排除其余食草类群；c) 仅排除牛类；d) 对照组，允许所有食草动物自由进入样地。
由于杂酚油灌丛样地全域禁止放牧牛只，因此仅布设3个重复实验区，处理组包括：a) 全面排除所有哺乳动物食草动物，涵盖兔形目动物与啮齿类；b) 仅排除兔形目动物；c) 对照组，允许所有食草动物自由进入样地。
每个样地内以系统布设的6×6点网格设置36个采样点，采样点间距为5.8米。每个采样点均设有1米×1米的永久性植被调查样方。1995年至2005年期间，每年春、秋两季均会测定各类土壤扰动（人类活动、兔类、牛类、羚羊、啮齿类等）的深度。2005年后，采样频率调整为每5年一次。本研究目前仍在持续进行中。