Category Archives: Undergraduate Research

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.

Continue reading Abundance Estimates And Vegetation Preferences Of The Suisun Song Sparrow In The Interior And Along Edges Of Impounded Wetlands

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Fecundity Decrease in Drosophila simulans in the absence of Wolbachia

By: Jack Taylor, Biochemistry and Molecular Biology ’15

Sponsor: Michael Turelli, Ph.D.

Ecology and Evolution

Many species of arthropods host Wolbachia, maternally transmitted bacteria that often influence host reproduction. This manipulation of host reproduction has contributed to Wolbachia becoming a normally-present infection of many Drosophila simulans. The Y36 isofemale line, a population of Drosophila simulans created from a single female collected in 2010 in Yolo County, produces flies which have an unusual phenotype when reciprocally crossed with uninfected simulans populations denoted U. The cross between Y36 male and U female produces female offspring with significantly lower fecundity than the reciprocal cross (Y36 female with U male). It is possible that this effect is a result of a paternal defect gene that is masked by the Wolbachia infection. Ten separate sublines were created from the Y36 isofemale line. The goal of my experiment was to determine whether this phenotype is still present among each of the ten sublines and if there is any variation in the phenotype among the sublines. Analysis of the data indicates that the qualitative effect of the phenotype has been preserved across the sublines but suggests that there is quantitative variation amongst them.

Dissecting the signaling pathway regulating early stages in parasitic plant, host plant interactions

By Lee Nguyen, Biotechnology ’14

Parasitic plants pose a serious threat to the world’s agriculture and environment.  Understanding the parasitism signaling pathway will help identify methods of pest control as well as pest resistance. One gene that enters the parasitic signaling pathway early is TvQR1, a gene that encodes an enzyme that catalyzes an oxidation-reduction reaction crucial for development of a root like outgrowth called a haustorium. In parasitic plants, TvQR1 is transcriptionally activated upon host contact and my project is to study the promoter of this gene, pQR1, in a nonparasitic plant. Continue reading Dissecting the signaling pathway regulating early stages in parasitic plant, host plant interactions