Wayne Sousa, Professor

Closed (1) Population dynamics of bloom-forming algae in San Francisco Bay

Closed. This professor is continuing with Fall 2018 apprentices on this project; no new apprentices needed for Spring 2019.

Green algal blooms occur naturally following the clearing of space by sand or loose cobble scouring on temperate rocky shores in spring and summer or by ice-scour at higher latitudes. Typically, the duration and size of these blooms are controlled by molluscan and crustacean herbivores, but high nutrient loading can generate unnaturally prolonged blooms of high biomass. In the later stages of these blooms, senescent individuals detach from the substrate and can accumulate in large floating or benthic mats, which gradually die and decay, creating harmful anoxic conditions. This study will monitor standing stock biomass of blooming macroalgae populations through time along a shoreline in SF Bay and investigate overwintering potential of Ulva's microscopic reproductive stages.

Most of the work will be done in the lab, the URAP intern will have the opportunity to assist with any of the following tasks:
1. Processing photos and percent cover estimation of algae in photographs using Photoshop

Students applying to this project should mention in their application why they are interested in the study system, techniques and any related previous experience.

Students will learn to identify common seaweeds found in San Francisco Bay and how to use image software to collect data. Interns will have the opportunity to discuss their work and career interests with Professor Sousa and his other graduate students, who conduct research in a variety of ecosystems.

Day-to-day supervisor for this project: Rosemary Romero, Ph.D. candidate

Qualifications: Reliable individuals with good communication skills, ability to pay strong attention to detail and not afraid to ask questions should apply. Experience with photography, Photoshop and Excel spreadsheets are a desirable, but not a requirement. Students must be willing to spend time managing data in Excel spreadsheets; data entry and management can be tedious but is very important to the success of these projects.

Weekly Hours: 6-8 hrs

Related website: https://doi.org/10.3733/ca.2017a0014
Related website: http://ib.berkeley.edu/labs/sousa/romero.html

Closed (2) Effects of non-native plant invasions on the diversity, species composition, and trophic structure of grassland invertebrate assemblages

Closed. This professor is continuing with Fall 2018 apprentices on this project; no new apprentices needed for Spring 2019.

California coastal grasslands have been reduced to less than 10% of their original area, and invasive, non-native plants often dominate remaining patches. These invasive species can greatly impact key ecosystem processes such as nutrient cycling, either directly through their unique traits or indirectly by altering food web dynamics. Along with litter quality and abiotic conditions, ground-dwelling invertebrates can play a critical role in litter decomposition. This study will document how invasions of plants with different life history and structural traits are altering the ground-dwelling arthropod communities in a coastal prairie on the edge of SF Bay.

Each URAP will have the opportunity to assist with lab work in the Sousa lab, and field work at the Richmond Field Station, including:
- Deploying and collecting pitfall traps,
- Sorting and keying collected arthropods to order and functional group,
- Characterizing pitfall trapping plots (including plant cover, litter depth, soil moisture and temperature)

Interns will gain experience in field sampling methods, experimental design, and arthropod collection and sorting., Graduate Student

Qualifications: A good candidate will be reliable, enthusiastic, able to work independently, and interested in both field and lab work. A background in arthropod identification and light microscopy as well as Excel is desirable but not essential.

Weekly Hours: 6-8 hrs

Off-Campus Research Site: Richmond Field Station, 1301 S 46th St, Richmond, CA 94804

Related website: http://ib.berkeley.edu/labs/sousa/index.html
Related website: http://rfs-env.berkeley.edu/index.html

Closed (3) Nocturnal transpiration in parasitic plants

Applications for Spring 2019 are now closed for this project.

Parasitic pants are plants that obtain water and/or nutrients from host plants. Although parasitic plants are found in nearly all ecosystems, the role of this distinct group has not been well-studied. Increasingly, however, parasitic plants are recognized for their considerable impact on community structure and function through a variety of mechanisms (including impacts on host species, effects on herbivores via their hosts, deposition of nitrogen rich litter, and high transpiration rates). This project focuses on diurnal transpiration patterns in a sub-group of parasitic plants, root hemiparasites, and how they deviate from typical transpiration patterns.

As a URAP you will primarily be responsible for processing leaf samples collected in the field. This includes photographing leaves and digitally analyzing them.

If there is interest, you may also conduct some field work with myself and/or independently. Fieldwork consists of taking soil moisture and transpiration measurements on parasitic plants and their hosts both in the daytime and nighttime (i.e. after dark). The extent to which you conduct fieldwork largely depends on your enthusiasm and interest.

In addition, some weeks may be devoted to helping with other URAPS or graduate students with other projects,aiding in various other aspects of maintaining and executing field experiments. Tasks may include: preparation of field materials, literature searches, and data entry.

You will be required to log a certain number of hours per week. Once you're trained in the lab techniques the scheduling is flexible and digital image analysis may be done remotely. many folks prefer to work in the lab, and space will always be available for you. By the end of the semester the URAP will gain an understanding of the project background and goals, selected lab techniques in ecology.

Day-to-day supervisor for this project: Audrey Haynes, Ph.D. candidate

Qualifications: A good candidate will be reliable, enthusiastic, thorough, able to work independently and not afraid to ask questions. Some coursework in ecology and experience with excel, R, and/or digital image analysis is desirable but not essential.

Weekly Hours: 3-5 hrs

Closed (4) Herbivory and nutrient cycling after chaparral fire

Closed. This professor is continuing with Fall 2018 apprentices on this project; no new apprentices needed for Spring 2019.

Periodic fire in California’s dense chaparral shrub vegetation can have complex effects on plant and soil nutrient dynamics. Nutrients are volatilized from live plant fuels and soils or deposited in a rich ash layer, which is highly susceptible to leaching. Immediately after fire, chaparral ecosystems experience a pulse of ephemeral flora from dormant seed banks, which almost entirely dies back by the third year after fire, thus not forming a long-term component of the shrubland community. While floristic studies have characterized this “charismatic” suite of herbaceous plants, few studies have examined the role this short-lived community plays in ecosystem nutrient dynamics and shrub community succession. In this experiment, fire-following herbs will be selectively removed from plots to evaluate the extent to which these plant communities immobilize soil nitrogen after chaparral fire. In addition, large exclosures will be erected to test how mammalian herbivory affects soil nutrient cycling in post-fire chaparral.

The URAP will primarily assist in soil science lab work at U.C. Berkeley. Tasks will include extracting available nitrogen from soils, measuring soil carbon and nitrogen cycling, and preparing samples for elemental analysis. The URAP will have the option of participating in some weekend fieldtrips to the Hopland Research and Extension Center. This intern will gain skills in field sampling methods, experimental design, and soil science.

Day-to-day supervisor for this project: Lindsey Hendricks-Franco, Ph.D. candidate

Qualifications: A good candidate will be reliable, enthusiastic, and willing to take part in detailed lab work. Background in plant or soil ecology would be helpful, but it is not required. Good common sense and attention to detail are a must.

Weekly Hours: to be negotiated
Related website: https://baynature.org/articles/landscape-shaped-fear/