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The overall goal of the rainfall manipulation project is to understand the coupled ecological and hydrological responses of a grassland, shrubland and a mixed grass-shrub vegetation community to extended periods of increased or decreased rainfall. Rainfall manipulation plots have been established in each of these three vegetation communities in the Five Points area of Sevilleta National Wildlife Refuge. In each vegetation community, three control plots, three drought treatment plots, and three water addition plots have been installed, each approximately 10 x 15 m in size. In each plot, vertical profiles of soil moisture probes have been installed under each cover type (canopy and interspace in grassland and shrubland; grass canopy, shrub canopy and interspace at the ecotone (mixed grass-shrub) site). The probes measure differences in infiltration and soil water content and potential associations with these different cover types. In addition, TDR probes have been installed diagonally in each cover type to integrate the water content of the top 15 cm of soil. Each plot contains 18, 1m2 quads made up of 6, 1m2 quads along each of the 3 transects located across each plot. Each spring and fall, the following parameters are measured in every quad: live plant cover, height, and abundance by species; dead plant cover; soil cover; litter cover; and rock cover. Data collection began in the drought and control plots in the spring of 2002. Data collection began in the water addition plots in the spring of 2004.In the grassland and shrubland communities, all nine currently established plots are located together. The three drought plots were located under a single large roof with a 0.5 m path separating each plot (drought treatments ended in 2006). The control plots and water addition plots are similarly grouped, but without the shelter structure. In the ecotone community, the plots are in three groups; each group is comprised of one drought plot, one water addition plot, and one control plot. Control plots received no experimental treatment, while the sliding roofs over the drought plots were used to divert precipitation, producing a long-term drought. The roofs covering the drought plots were lowered when there was no precipitation so that the amount of sunlight received by the drought plots was minimally affected. Water addition was intended to impose a complementary increase in water supply on the water addition plots.
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Drought Impact on Desert Ecosystems, Drought Network precipitation manipulation experiment in desert grasslands
Climate change amplifies the global water cycle, making droughts more frequent and more severe. The hot deserts of the U.S. rely on the stability and frequency of water availability in order to sustain biological communities, making these ecosystems incredibly vulnerable to anticipated alterations in the water cycle. This project seeks to understand which biotic and abiotic variables are principle in determining desert ecosystem sensitivity to drought? To answer these questions, we have installed a drought manipulation that will simulate an extreme drought event by reducing annual precipitation by 66% in seven desert sites. Plant abundance data are collected annually to track changes in the plant community. Data collection began in Spring 2018. Treatments at three Sevilleta sites began in Fall 2018 after data collection in October 2018. Treatments started at four sites in Arizona and California in March and April of 2019 and spring pretreatment data collection. The treatments will last for four years.
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- PAR ID:
- 10424094
- Publisher / Repository:
- Environmental Data Initiative
- Date Published:
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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