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Abundance Estimates And Vegetation Preferences Of The Suisun Song Sparrow In The Interior And Along Edges Of Impounded Wetlands
By Debi Fanucchi, Oscar Garzon, Julia F. Herring, and Kevin M. Ringelman
ABSTRACT
The Suisun Song Sparrow (Melospiza melodia maxillaris) is a subspecies of Song Sparrow that is endemic to the Suisun Marsh of California. It is listed as a state species of special concern by the California Department of Fish and Wildlife due to its restricted range, small breeding population, and susceptibility to encroaching human development. The Suisun Marsh ecosystem is highly altered, and is comprised of both natural tidal wetlands and impounded wetlands that are cut off from the natural tidal cycle. Suisun Song Sparrows are believed to prefer natural tidal wetlands, but there is a lack of information on sparrow densities and habitat associations in impounded wetlands. To address this knowledge gap, we examined the abundance and habitat preferences of Suisun Song Sparrows in an impounded and heavily managed wetland complex. We conducted surveys at seven sites within interior managed (impounded) wetlands, and seven sites along edges between tidal and impounded wetlands. We found significantly more birds in interior sites than at edge sites, but within edge habitat, abundances were higher on the tidal side of the levee. We found that Song Sparrows used tall vegetation in greater proportion than its abundance, and specifically preferred bulrush and common reed as calling perches. Interior sites contained relatively less of this preferred vegetation than edge sites, suggesting that beneficial habitat heterogeneity in interior sites, and/or deleterious edge effects along the dikes may be important drivers of abundance. In the face of sea-level rise and shifting conservation priorities, many managed wetlands are expected to be converted back into fully tidal systems, and our results provide an important baseline for future research on the effects of tidal restoration.
Vector and Disease Management Research to Reduce the Effects of Pierce’s Disease in California’s Vineyards
By Natalie Swinhoe, Anthropology and Evolution, Ecology, and Biodiversity, 2015
Pierce’s Disease in grapevines is a major threat to California’s viticultural economy. Caused by the bacterial strain Xylella fastidiosa, the disease blocks water transfer in the xylem of stems, leading to water stress and eventual death. Until the 1990s, the only carriers for the disease were native Blue-Green Sharpshooters, Graphocephala atropunctata. However, between 1994 and 2000, a devastating outbreak occurred in Southern California, destroying more than 1000 acres of vineyards (Ringenberg et al., 2014). This epidemic was caused by a new nonnative vector- the Glassy-Winged Sharpshooter, Homalodisca vitripennis (Tumber et al, 2013). Compared to the Blue-Green Sharpshooter, the Glassy-Winged Sharpshooter has a much greater capacity to spread Pierce’s Disease because it can fly further and feed on a larger variety of plant parts (Alston et al., 2013, Baccari and Lindow, 2010).
Learning from Drought in California: Past and Present
By Marisa Sanchez, Molecular and Cellular Biology, ’15
The most current drought in California is considered to be one of the worst droughts in the past century, and many wonder if this severity is due to climate change. However, California has had a long history of unpredictable weather fluctuations, and is familiar with severe droughts. Many droughts can have devastating effects, particularly in the agricultural industry and the hydropower industry. Most Californians have also experienced the effects of a drought first-hand, such as having enforced water rationing. Even though, California’s history has shown that most droughts have devastating effects, droughts can also great learning experiences.
Viruses and the Global Metabolic Pathway
By Oyang Teng, Biological Sciences ’14
Microbes are the planetary engineers of the biogeochemical cycles that sustain all life on earth. At the molecular scale, the biological turnover of such key elements as hydrogen, carbon, oxygen, nitrogen, iron and sulfur depends on the enzymatic transfer of electrons from reduced (electron-donating) to oxidized (electron-accepting) forms of these elements. On the global scale and over geological time, reduced substrates and oxidized products map to a vast, often circuitous flux between the interior depths of the mantle and the oceans, land, and atmosphere.