About This Project

The San Francisco Bay Area's salt ponds represent a vital part of California's history and biodiversity. Hypersaline ponds, with salinities up to 3X that of the ocean, are toxic to most forms of life, yet some invertebrates flourish in or around these waters. This study documents insect biodiversity in ponds or ditches of varying salinities. We hypothesize that increasing salinity will lead to minimal impacts on terrestrial species, but reduce diversity of aquatic species.

Ask the Scientists

What is the context of this research?

The South Bay Salt Ponds (SBSP) in the San Francisco Bay Area have a storied history. They were originally natural salt marsh ecosystems utilized by the Indigenous Ohlone. They were then bought up by the food conglomerate Cargill, which utilized ponds for massive salt mining operations. Since 2003, many of the salt ponds have been or are being converted back to natural tidal wetlands, the result of a massive effort known as the South Bay Salt Pond Restoration Project (SBSPRP).

Hypersaline ponds are osmotically stressful. They can lead to ion toxicity due to disrupted cellular gradients, and deactivate enzymes. Despite this, many organisms live in or near saline ecosystems. Insects living in or near these ponds are not as documented as other taxa, despite serving as an important food source for charismatic fauna such as snowy plovers. Some studies show negative relationships between salinity and diversity, but it is unclear if this is true for insects, and salinities >30 ppt.

What is the significance of this project?

By using sweep-net sampling techniques, we can get a better understanding of which insects are living in the current or former salt ponds, using both genetic tools (e.g. ATBI) and morphological specimens that will be maintained in perpetuity at the Cal Academy of Sciences. While the ideal time to have begun these surveys is 20 years ago, now is the next best time.

As some of the ponds being sampled are part of the SBSPRP, these surveys may also serve as baselines for us to determine how restoration efforts are affecting insect populations and phenotypes over time.

What are the goals of the project?

Genetic curation: ATBI sampling. Insects will be sweep-netted from different ponds in the SBSP system. Important chemical information about the water, such as the salinity, pH, and temperature will be collected. There will be one set of samples that includes insects in the water and those near the water. Results will tell us about how insect diversity and composition differs between ponds of different water chemistries, and between those living in aquatic vs. terrestrial environments.

Morphological curation: Specimen collection for deposition at Cal Academy. Insects will be aspirated with sweep-nets or aquatic collection nets using the same sampling methods as above; however, physical specimens will be preserved and pinned for deposition at the Cal Academy of Sciences. The goal is to collect at least 50 representative insect specimens per site.

Outreach: Results will be shared with the public at Don Edwards, which hosts weekly free lectures and events.