Week 3 in the California Central Valley Wildlife Refuges

I am coordinating a survey that estimates the amount of seeds produced by species that migratory birds need as a food source in the central valley of California. I will be working alongside staff at three wildlife refuges from Kern National Wildlife Refuge (NWR) near Bakersfield to Modoc NWR near the Oregon border. These refuges manage portions of land as wetlands, meaning that they flood the land and then draw down the water periodically during the year. This process allows highly nutritious food sources for waterbirds, like swamp timothy and watergrass, to grow preferentially over other plants.

The interesting thing about my internship is that I am simultaneously refining and adding to the protocol for this survey, writing annual reports using survey data from previous years, and conducting fieldwork to get data for 2021. I spent the first two weeks at the regional Inventory and Monitoring office in Sacramento getting oriented and reading through the protocol for the survey, standards of procedure, and other guidance documents. Then I set off to Kern NWR to begin collecting data.

The refuge biologist, some crew members, and I set out early in the morning to take advantage of the cooler air. We drive on roads and levies that act as borders around the refuge subunits, stopping when close to random sample points on our maps. We then proceed on foot through the dry vegetation in the subunit until reaching the point, stopping to take measurements of swamp timothy and watergrass. One person takes charge of estimating the percentages of the food species within a 15 meter circle plot, while others count the number of seeds within a quadrat (a 30cm2 metal square) and measure the lengths of seeds. These numbers go into a model that estimates the total amount of food in the refuge for waterbirds.

This week I begin processing and analysing the data. I am curious to see how seed production this year compares to the other years where we have data, 2019 and 2020. Once we have three years of data we can begin to see trends in which management actions (tilling or mowing) increase seed production of the food species and which subunits have the most potential for improvement.

In conducting the survey, I have also learned about the planning and management actions that go into running a wildlife refuge. This includes getting water delivered to the refuge and correctly timing the flooding of subunits so that they act as wetlands, even though the area does not naturally flood anymore. The crew and maintenance workers mow the subunits, till the land and remove invasive salt cedar trees. The refuge staff put up cameras to spot shrews and kit foxes, conduct bird surveys, and monitor lizard populations. Now that most of the data for Kern has been collected for the food species survey, I am looking forward to joining refuge staff to observe different tasks they do during a week.

Agency: U.S. Fish and Wildlife Service

Program: US Fish & Wildlife Service - DFP

Location: Modoc National Wildlife Refuge