Fieldtrip Cancelled: Sears Point Tidal Wetland Fieldtrip

Sears Point Tidal Marsh 

This fieldtrip is cancelled- we will meet as usual for class at 12 noon- this quiz will be extra credit!

We will be visiting the tidal marsh restoration project that is adjacent to Sears Point Raceway. The goal of this fieldtrip will be to learnabout

• wetlands- tidal marshes specifically
• the impact of human development on marshes
• the important role they play in protection of wildlife, against flooding

the process of restoring these wetlands.

Assignment

Part I: Read the background material below and take the online quiz

Part II: attend the fieldtrip- in order to receive full credit on this assignment you will need to do both. 

Directions

• 12 noon: We will leave from the classroom - please do not be late, we will not be able to wait for you  Here is the link to sign up for spots in the van (there are 11 spots) 
• 12:45pm: Meet at the Sears Point Trailhead  The address 7699 Reclamation Rd, Petaluma, CA 95476 will also get you there.
  • If you're coming from Lakeville Hwy, you'll arrive at the stoplight intersection with 37. Proceed straight through and drive to the parking lot at the end of the road, next to the yellow gate. This is where we'll meet. As a group, we will drive through the gate and park near the levee where we can walk around. 
  • If you get lost finding the trailhead, you can call Riley Scaff from the Sonoma Land Trust who will be leading the trip  (310) 913-4318). 
  • She recommends that you NOT use Apple Maps.
• 3:30pm  We will return to campus and start lecture at 3:30pm 

Background Information- by Riley Scaf

Sears Point Tidal Restoration Project

TLDR: Restoring diked (built up barrier to retain water) Baylands to tidal wetland is an important piece of climate adaptation in the Bay Area. North Bay is one of the best places to do it (less infrastructure and development than South Bay). Sears Point is one of dozens of tidal projects all over the bay area. Even though it’s young (almost 10 years old!) it already hosts a vibrant community of migratory shorebirds (come visit in January for birding!), fish and plants.

Baylands History

Before the 1850s, much of the land on the shore of the San Francisco Bay was tidal marsh that had probably been around for up to 6,500 years (sea level was way lower before this because of the ice age so the whole SF bay would’ve actually looked a lot like the Delta does now). Indigenous groups including the Coast Miwok and Southern Pomo (now represented by the Federated Indians of Graton Rancheria) stewarded these marshes for millennia and utilized them for food, waterways, etc.

Displacement of these tribes began during the Spanish Rancheria system (~1769-1821) when Spain set up missions all over California (look for those little mission bells along highways). CA was part of Mexico for about 30 years before it became part of the US, when settlers continued displacing Indigenous tribes and built levees (elevated earthworks to keep water from flooding an area) to drain the Baylands and convert them to farmland. Many of these lands are still hay farms and ranches. Over the past 150 years, the land has sunk as much as 5-7 feet as the organic matter in the soil is exposed to oxygen and breaks down.

Tidal Restoration:

Climate change is expected to drive significant sea level rise in the coming decades, as well as more extreme storms. Already, a storm surge combined with a very high tide could flood sections of the SMART rail line. Tidal marshes are critical to breaking waves and buffering coastal communities from sea level rise. They also support vibrant ecological communities, sequester(storing) carbon dioxide, cycle nutrients, filter groundwater and provide outdoor spaces for people.

By digging tidal channels and breaching levees, we can give these former marshes back to the bay. Tides bring in sediment and reverse the land subsidence. If we restore these in the 20-30 years, the marshes will rise along with the sea level, preventing them from drowning. If we don’t many of these marshes will be lost.

The tidal restoration that we’re going to see (full name: Sears Point Tidal Wetland Restoration Project) was done in 2015. The whole place began as “subtidal” habitat, meaning it was constantly underwater. Shallow subtidal habitat often supports eelgrass—great habitat for fish. Over time, it has evolved into a “mudflat” where mud (without plants) is exposed at low tide. In the future, it’ll make its way to “low marsh” dominated by cordgrass (we’ll see cordgrass growing at the edges), and mid/high marshes dominated by pickleweed (we’ll see lots of that too). The sequence from subtidal-mudflat-low marsh-high marsh is called an ecotone. Complete ecotones are critical to healthy salt marshes because different creatures utilize different habitats, and some of them move through habitats with the tides (if you’re a western sandpiper, you munch in the mudflat, but where do you go when the tide rises?)

Extra for anyone who loves birds: (this was written the supervisor who spearheaded this project, Julian Meisler)

The site has been utilized extensively by resident and migratory shorebirds and waterfowl. Species assemblages and uses have changed as site elevations rose. In the early days, the deeper water attracted more diving ducks and pelicans with shorebirds found less often and only around the intertidal margins. As elevations rose, the emerging mudflats presented vast habitat extents for shorebirds and more narrow use by deeper water birds as suitable water depths had shorter durations. That being said, thousands of waterfowl have been observed each year during surveys, with Canvasbacks being the most abundant followed by Ruddy Duck, Greater Scaup, and Bufflehead. Dabbling ducks were present in lower numbers, led in abundance by Northern Pintail, American Wigeon, and Green-winged Teal. Least sandpiper, Dunlin, Willet, Western Sandpiper, American Avocet, Marbled Godwit, Black-bellied Plover, and Long-billed Dowitcher were the most abundant shorebirds. Canada geese were observed nesting and raising broods in the early years but have not been observed more recently.

Extra for anyone who loves fish: (also by Julian Meisler)

One of the most striking (and expected) uses is by bat rays, evidenced by the thousands of foraging divets readily observable in air photos. Beyond that, fisherman are commonly observed on their boats in the site especially near the breaches, catching striped bass. Two fish sampling events were completed in May and October 2017, which yielded a total catch of 14,358 individual fish, with far higher fall abundance (12,766 fish) vs. spring (1,592 fish). Eighteen species total were collected along with three crustacean species. The fish community in spring was dominated by native Bay Goby, Starry Flounder, Topsmelt, and Pacific Staghorn Sculpin. Non-native gobies (Chameleon, Shimofuri, Shokihaze, and Yellowfin) and Striped Bass were also abundant. In fall, the native Topsmelt and Pacific Herring accounted for about 88 percent of the entire fish catch. Striped Bass was the most abundant non-native fish, followed by Chameleon and Yellowfin gobies. Two additional fish species, White Sturgeon and Bat Ray, were visually observed by field crews but were never collected.