Reconnaissance satellite photos show the recent history of shrub recruitment and survival in desert grasslands

Title	Reconnaissance satellite photos show the recent history of shrub recruitment and survival in desert grasslands
Publication Type	Conference Paper
Year of Publication	2000
Authors	Goslee S, Peters DC, Havstad K, Schlesinger W.H
Conference Name	85th Annual Meeting, Ecological Society of America
Date Published	August 6-10, 200
Conference Location	Snowbird, UT
ARIS Log Number	110161
Keywords	desert grasslands, history, Larrea tridentata, prosopis glandulosa, reconnaissance, satellite, shrub recruitment
Abstract	Certain shrub species, particularly Prosopis glandulosa and Larrea tridentata, have increased dramatically in the southwestern US during the past few decades, replacing the original grassland vegetation. We obtained a temporal series of high-resolution military satellite images beginning in the early 1960s, with the goal of monitoring shrub invasion over a large area to determine the topographic and climatic controls on shrub seedling establishment and the rate of expansion of shrub cover. Although the total area of shrub cover increased over time, both the number of shrubs and their size distributions were highly variable. Mortality in small shrubs was high, but once shrubs reached a threshold size, they were likely to persist for long periods. Shrub establishment and survival were related to both climatic factors and topographic features, particularly precipitation and drainage. Our results provide valuable information for those interested din the management and restoration of the desert grasslands of the southwestern US.