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United States Department of Agriculture (USDA) 2009

DEMOGRAPHY OF ARID-LAND SHRUBS : BASIC RESEARCH IN PLANT ECOLOGY WITH APPLICATIONS FOR RESTORATION AND MANAGEMENT OF DEGRADED ARID-LAND ECOSYSTEMS IN CALIFORNIA

Shrubs Restoration Degraded

United States Department of Agriculture (USDA) Research, Education & Economics Information System (REEIS)

Titre : DEMOGRAPHY OF ARID-LAND SHRUBS : BASIC RESEARCH IN PLANT ECOLOGY WITH APPLICATIONS FOR RESTORATION AND MANAGEMENT OF DEGRADED ARID-LAND ECOSYSTEMS IN CALIFORNIA

Identification : CA-D-EVE-5963-H

Pays : Etats Unis

Durée : Oct 1, 2009 à Dec 31, 2011

Domaine : Management of Saline and Sodic Soils and Salinity ; Desert and semidesert shrub land and shinnery ;

Partenaire : UNIVERSITY OF CALIFORNIA, DAVIS 410 MRAK HALL DAVIS,CA 95616-8671

Objectifs
This 5-year project investigates the dynamics of native arid-land ecosystems in the eastern Sierra Nevada of California. This research : 1) addresses the still unresolved debate on the occurrence of and mechanisms of plant succession in deserts ; and 2) tests hypotheses on the demography of perennial desert shrubs, from seeding establishment, recruitment of juveniles into the reproductive class, growth and reproduction of adults, and senescence. The 30-year span of data collection also enables reliable projections about long-term climate change and its effect on California’s arid-land ecosystems. The basic research contributions from this project have direct application to restoring natural ecosystems to ameliorate the impacts of stream diversions and groundwater pumping that cause ’desertification’ of large areas of the arid West. The primary application will be to aid restoration of self-sustaining ecosystems that suppress the generation of toxic dust (PM10 and smaller) on dry lakebeds or in areas adversely affected by groundwater pumping or grazing. OBJECTIVES : 1) To document long-term demographics of perennial shrub populations and recruitment, survivorship of seedlings along the environmental gradient created by the receding Mono Lake ; 2) to use the projected transgression of Mono Lake after the 1994 water rights decision as a natural (uncontrolled) experiment to document effects of ground-water depth on recruitment of seedlings to phreatophytic status (defined as reaching groundwater) ; 3) to test hypotheses about the recruitment of juveniles into the reproductive class, in particular whether episodic short-term climatic fluctuations caused by ENSO determines the timing of recruitment of reproductives ; 4) to build predictive models of long-term demographic trajectories of rabbitbrush, as a representative perennial, arid-land shrub, to explore among other things the effect of projected climate change due to global warming on arid-land ecosystems ; and 5) to apply information obtained at Mono Lake to design lakebed restoration protocols in the Owens Valley and other degraded arid-land ecosystems.

Descriptif
1) Two sites of different successional stages (500 years and 50 years since transgression of Mono Lake) will continue to be monitored for several environmental variables including depth to ground water and soil quality using standard methods in physical geography and ecological studies ; 2) at these two sites, we will continue collection of basic demographic data on previously marked shrubs (adults and large juveniles), specifically size of canopy, flowering and survivorship. Standard statistical methods and canonical vegetation ordination will be used to analyze these data ; 3) at these two sites, we will continue to follow seedlings mapped in the previous phase of study and annually to mark new seedlings to add to this census, again using standard field methods ; 4) a predictive population projection matrix model will be created and tested with a complete re-census of the 50-year-old plot, which has recruited many unmarked individuals into the juvenile and reproductive class since 1993. We will use RAMAS or specially written software.

Présentation : USDA

Page publiée le 29 novembre 2015, mise à jour le 7 novembre 2017