Small Mammal Exclosure Study (SMES) Vegetation Data from the Chihuahuan Desert Grassland and Shrubland at the Sevilleta National Wildlife Refuge, New Mexico (1995-2009)

This is data for vegetation canopy cover measured from each of the
SMES study plots. Vegetation canopy cover was measured from each of
the 36 one-meter2 quadrats twice each year. Animal consumers have
important roles in ecosystems, determining plant species composition
and structure, regulating rates of plant production and nutrient,
and altering soil structure and chemistry. The purpose of this study
is to determine whether or not the activities of small mammals
regulate plant community structure, plant species diversity, and
spatial vegetation patterns in Chihuahuan Desert shrublands and
grasslands. The purpose of this study is to determine whether or not the
activities of small mammals regulate plant community structure,
plant species diversity, and spatial vegetation patterns in
Chihuahuan Desert shrublands and grasslands. What role if any do
indigenous small mammal consumers have in maintaining desertified
landscapes in the Chihuahuan Desert? Additionally, how do the
effects of small mammals interact with changing climate to affect
vegetation patterns over time? This study will provide long-term
experimental tests of the roles of consumers on ecosystem pattern
and process across a latitudinal climate gradient. The following
questions or hypotheses will be addressed. 1) Do small mammals
influence patterns of plant species composition and diversity,
vegetation structure, and spatial patterns of vegetation canopy
cover and biomass in Chihuahuan Desert shrublands and grasslands?
Are small mammals keystone species that determine plant species
composition and physiognomy of Chihuahuan Desert communities? Do
small mammals have a significant role in maintaining the existence
of shrub islands and spatial heterogeneity of creosotebush shrub
communities? 2) Do small mammals affect the taxonomic composition
and spatial pattern of vegetation similarly or differently in
grassland communities as compared to shrub communities? How do
patterns compare between grassland and shrubland sites, and how do
these relatively small scale patterns relate to overall landscape
vegetation patterns? 3) Do small mammals interact with short-term
(annual) and long-term (decades) climate change to affect temporal
changes in vegetation spatial patterns and species composition? 4)
Do small mammals interact with other herbivore and granivore
consumers enough to affect the species composition and abundances of
other consumers such as ants and grasshoppers?

本数据集为SMES研究样地中测得的植被冠层盖度数据。研究对全部36个1平方米样方每年开展两次植被冠层盖度测定。
动物消费者在生态系统中扮演着核心角色，可调控植物物种组成与群落结构、调节植物生产与养分循环速率，并改变土壤结构与化学性质。
本研究旨在探究小型哺乳动物的活动是否会调控奇瓦瓦荒漠灌丛与草原中的植物群落结构、植物物种多样性及空间植被格局。本土小型哺乳动物消费者在维持奇瓦瓦荒漠荒漠化景观中发挥着何种作用？此外，小型哺乳动物的影响如何与气候变化相互作用，进而随时间推移改变植被格局？
本研究将通过跨纬度气候梯度的长期实验，检验消费者对生态系统格局与过程的调控作用。本次研究将围绕以下科学问题与假说展开：
1) 小型哺乳动物是否会影响奇瓦瓦荒漠灌丛与草原的植物物种组成与多样性格局、植被结构，以及植被冠层盖度与生物量的空间分布？小型哺乳动物是否为决定奇瓦瓦荒漠群落植物物种组成与外貌特征的关键种？它们是否在维持石炭酸灌丛（creosotebush）群落的灌丛岛结构与空间异质性方面发挥重要作用？
2) 相较于灌丛群落，小型哺乳动物对草原群落植被的分类组成与空间格局的影响是否存在异同？草原与灌丛样地的植被格局存在何种差异？这些相对小规模的格局又与整体景观植被格局存在何种关联？
3) 小型哺乳动物是否会与短期（年度）及长期（数十年）气候变化相互作用，进而影响植被空间格局与物种组成的时间动态变化？
4) 小型哺乳动物是否会与其他草食性、食谷性消费者产生足够强的相互作用，进而影响蚂蚁、蝗虫等其他消费者的物种组成与种群丰度？