Alison H. Purcell

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Urban streams have been the focus of much research in recent years, but many questions about the mechanisms driving the urban stream syndrome remain unanswered. Identification of key research questions is an important step toward effective, efficient management of urban streams to meet societal goals. We developed a list of priority research questions by:(More)
Numerous bacteria have been isolated from within plants, and many reported from xylem, but only three species of xylem-limited bacteria (XLB) that are fastidious in cultural requirements, are plant pathogens, and exclusively occupy xylem, have been well characterized. Two XLB, Xylella fastidiosa and Pseudomonas syzygii, are transmitted by sucking insects(More)
Long-term variability of bioassessments has not been well evaluated. We analyzed a 20-year data set (1984-2003) from four sites in two northern California streams to examine the variability of bioassessment indices (two multivariate RIVPACS-type O/E scores and one multimetric index of biotic integrity, IBI), as well as eight metrics. All sites were sampled(More)
A bacterial parasite (designated as BEV) of the leafhopper Euscelidius variegatus, which is passed transovarially to offspring, was transmitted from insect to insect via feeding of the insects in plants. The rate of bacterial infection of leafhoppers fed upon plants that had previously been exposed to BEV-infected leafhoppers declined with an increase in(More)
Spiroplasmas were cultured from nonsurface-sterilized flowers of magnolia tree (Magnolia grandiflora L.) and tulip tree (Liriodendron tulipfera L.) in Alameda, Solano, and Yolo counties in California. Spiroplasmas were also isolated from honey bees (Apis mellifera L.) collected in the vicinity of Davis and Berkeley, CA. Most of the isolates grew relatively(More)
Step-pools sequences are increasingly used to restore stream channels. This increase corresponds to significant advances in theory for step-pools in recent years. The need for step-pools in stream restoration arises as urban development encroaches into steep terrain in response to population pressures, as stream channels in lower-gradient areas require(More)
Despite the biological, social, and physical challenges that exist in urban creek restorations, there are opportunities to effectively involve local residents in ecological rehabilitation projects. An urban riparian restoration project along Strawberry Creek (Berkeley, CA) began with the goal of removing exotic vegetation and restoring native plant(More)
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