Benny at Sedgwick.
Undergrad Research Symposium
Undergrad Research Symposium

Vernal Pool DNA

Alyssa Jain, Jessica Sofian, McKenzie Goetz, Phil Arrajj, Cara Orndahl, Bridget Murphey, and Ingrid Serafin are developing a new methodology to detect aquatic invertebrates in vernal pools by scooping up water samples.  From this water, we can extract fragments of DNA sloughed off from the invertebrates, amplify the DNA, and sequencing it to determine what species are present in a restored vernal pool.  Alyssa, Phil, and Ingrid presented their work at the EEMB Undergraduate Research Symposium, which is an annual event that brings together all the undergraduate researchers in EEMB to share their projects and experiences in the department.

Benny with exclusion cages at Sedgwick.
Benny with exclusion cages at Sedgwick.

Grassland Restoration - Benny Drescher

After assisting with the lab’s research on grassland restoration for several years, Benny was inspired to investigate why one experimental site at Sedgwick Reserve garnered substantially less native plant establishment than the other experimental site nearby. In collaboration with Maddie Nolan, he used field and greenhouse experiments to test two hypothesized drivers: seed loss to foraging animals vs. different soil characteristics at the two sites. In his field experiments, he constructed seed-baited track pads to assess granivore activity, deployed trail cameras to capture animal visits, and applied native seed mixes to caged and uncaged plots to tease apart the effects of soil, seed mix, and seed foragers.

From his greenhouse experiments, he found that germination did not differ between the two soils. This suggests that seed foragers, rather than soil dynamics, were the likely cause of the distinct restoration outcomes. Evidence from his field experiments also supports this finding. After Benny finishes working through the data from his field work, he plants to submit his project's findings to a peer-reviewed journal for publication. In addition to having conducted a study that will serve useful to restoration practitioners and researchers of California grasslands, Benny has provided himself with a much deeper learning experience than any university classroom could provide.

GIS Mapping - Shane Dewees

Obligate seeders fill the critical role of extending chaparral communities to more xeric and nutrient poor areas (Keeley 1986). This also helps to lower chaparral’s overall vulnerability, since xeric, nutrient-poor areas are less vulnerable to invasion by invasive species (Keeley 2004). Obligate Seeders are also a more drought resistant functional group than either obligate or facultative resprouters are (Keeley 1986); a feature of growing importance as Southern California’s drought persists and available groundwater continuously diminishes.  Therefore, a potential reduction in obligate seeders could pose a detrimental threat to the long-term stability and perseverance of chaparral communities. This study uses Vegetation Type Mapping (VTM) data collected by Wieslander in 1934 and CALVEG (Classification and Assessment with LANDSAT of Visible Ecological Groupings) data from the U.S. Forest Services, collected in 2009 to look at the change in chaparral and obligate seeders’ distribution in the Ventura and Los Angeles counties of Southern California from 1934 to 2009. We have found that while 77.81% of the original chaparral area identified in 1934 still remains as chaparral, only 35.36% of the original area defined as obligate seeders remains as obligate seeders. We then analyzed the influence of 10 different variables on the observed conversion with a random forest analysis. This showed that elevation, minimum January temperature, and mean annual precipitation were the most influential variables on conversion, with conversion occurring at lower elevations, with higher minimum January temperatures, and less precipitation. These findings can help us identify future areas of obligate seeder dominated chaparral most vulnerable to conversion and allow us to focus more conservation efforts there.


Germination in native soil - Thomas Aronson

Germination of native woody species in the field has almost no successful establishment despite success in the greenhouse. Therefore, we investigated possible inhibitors of several native woody shrubs used in chaparral restoration.  We investigated whether inhibition was occurring due to soil differences between the greenhouse and field. Our results showed that germination was higher in the native soil versus greenhouse soil. These findings show that native field soil is not inhibiting germination, pointing towards environmental factors as the germination and/or establishment inhibitors.