Oh, the places you’ll go: Anza-Borrego Desert State Park

Earlier this year, I completed a survey of the plants and arthropods in a weed management area of Anza-Borrego Desert State Park.

The University of California Steele-Burnand Anza-Borrego Desert Research Center in Borrego Springs, CA.

The University of California Steele-Burnand Anza-Borrego Desert Research Center in Borrego Springs, CA.

This particular area along Henderson Canyon Road in Borrego Springs, right in the center of Anza-Borrego Desert State Park, has been used as a demonstration plot for the effects of hand-weeding Brassica tournefortii (Sahara Mustard) over the past ~10 years. Every winter, a team of volunteers sweeps the area removing all of the seedling plants before they grow, flower, and reproduce. I visited 3 times over the growing season – check out the dramatic change in the landscape in these photos each 1 month apart!

Similarly to my other field survey experiment (click here) I use pitfall and pan traps to collect arthropods that walk, crawl, fly and otherwise move through the study site.

The traps are left out for 24 hours, then all the specimens captured are collected and brought back to the lab.

In the course of studying the flora and fauna of this area, I had the great pleasure of viewing flowers upon flowers, and insects galore!

The field season is long over for Anza-Borrego – it’s a very short field season! The organisms in this harsh desert come and go quickly while conditions are favorable, and wait out the long, hot summers as seeds, eggs, dormant live stages, or even migrate somewhere else. Here’s hoping for a good rain year in 2015-2016 to bring up lots of desert wildflowers next winter and spring!

*This research was supported by the Anza-Borrego Foundation Howie Wier Memorial Conservation Grant (2014).

Oh, the Places You’ll Go: Oasis de Los Osos Reserve

Today’s post is all about the work I’ve been doing at a University of California Natural Reserve in eastern Riverside County, Oasis de los Osos. For nearly 2 years, I’ve been visiting Oasis de los Osos regularly to monitor plants and arthropods.

Oasis de Los Osos Reserve Sign

Welcome to the Oasis de los Osos Reserve! Source: http://www.wikiloc.com/wikiloc/imgServer.do?id=3734415

Oasis de los Osos is a small reserve (65 hectares) adjacent to the Snow Creek community of Palm Springs, CA. A perennial stream “Lamb’s Creek” runs through the reserve and supports dense riparian vegetation, amphibians, and many other critters seeking reprieve from the desert heat. The remains of a former home sit alongside the stream near the southwestern edge of the reserve; it was allegedly built in the 1930s by Denver and Lucy Ellen Lamb (see this site for more details).

Snow Creek House

The old Lamb house at Lamb’s Creek. Source: http://www.wikiloc.com/wikiloc/imgServer.do?id=3734443

My monitoring study is set up to assess the plant and arthropod biodiversity that occurs close to and distant from the perennial stream, and changes that occur along its drying portion. In particular, I aim to figure out how plants and arthropods respond to the presence and dominance of the invasive weed, Brassica tournefortii.

Twelve transects are established at every 100 meters along the stream, from the perennially flowing region at slightly higher elevation, to the seasonally wet/dry region below. Within each of these transects, five plots are set up at 0, 4, 8, 16, and 32 meters away from the stream edge. This design allows me to compare the identity and diversity of plants and arthropods that occur at varying positions along the stream, and at varying distances away from it.

Snow Creek Transect Map

A Google Earth view-map of my monitoring study area at the Oasis de los Osos reserve. Each red balloon indicates the twelve transects where plants and arthropods are regularly censused November – June.

At each plot, I have set up one pitfall trap and one platform for a set of pan traps. Pitfall and pan traps are used to passively sample arthropods that occur in the area. Pitfall traps capture critters walking along the ground, and are often used when targeting detritivores, predators, and shy critters. Pan traps capture flying arthropods that come in to land on what they likely thought was a flower; pan traps are generally used when targeting pollinators and other flower-visitors. Because they sample different kinds of arthropod critters, I use both kinds of traps at each plot to assess what kinds of animals live there.

A pitfall trap (left) in the soil, and one set of three pan traps (right) mounted on a platform above the soil.

A pitfall trap (left) in the soil, and one set of three pan traps (right) mounted on a platform above the soil.

Pitfall and pan traps are left open for 24 hours each census period. At this time, the plants growing at each plot are also censused to document variation in which species are present.

Several people help me with each census – 60 plots is a lot! We each set up traps at a few transects on the first day, carefully opening pitfall traps, attaching pan traps, and filling them with soapy water. Hiking with water jugs is made much easier with several helping hands.

On day 2, we each work at a few transects to collect all of the specimens captured in the pitfall and pan traps at every plot. The soapy water and contents are emptied from the trap cups into special baggies to be transported back to the lab, all the cups are collected, and the pitfall traps are closed and covered up to prevent any critters getting in there between censuses.

We’ve found some pretty interesting critters in these traps! There have been 30 different orders of arthropods identified (An order is a taxonomic grouping level above family but below class. For example, ants and bees are in the order Hymenoptera, while butterflies and moths are in the order Lepidoptera).

Back at the lab, all the samples are transferred to glass vials with ethanol and given labels to keep track of where and when they came from.

Once all specimens are transferred into glass storage vials with ethanol, they are ready to be examined under a microscope, identified and counted. This data will be used to understand the arthropod community at Oasis de los Osos, how it changes in response to the plant community, time of year, and other environmental variables.

Stay tuned for updates as more data is generated and analyzed!

A beautiful view of the Oasis de los Osos reserve, Lamb's Creek, and the San Jacinto Mountains

A beautiful view of the Oasis de los Osos reserve, Lamb’s Creek, and the San Jacinto Mountains

Unless otherwise noted, all photos used here are my own. Please feel free to comment or contact me with questions!

Update: Additional information and press on this research and the Oasis de Los Osos Reserve can be found here and here.

Oh, the Places You’ll Go: San Clemente Island

Recently, I had the privilege of visiting San Clemente Island. San Clemente is one of the Channel Islands, off the coast of southern California. It’s south of Santa Catalina and is not visited by tourists.

San Clemente Island, the whole island, is a base of the U.S. Navy. As a military base, and particularly as an island military base, the entry of persons is highly restricted and carefully regulated. So, when the opportunity to visit San Clemente Island presented itself, I took it!

My opportunity came thanks to two friends and colleagues in Dr. Erin Rankin’s lab (http://www.faculty.ucr.edu/~eewilson/).

Sheena is a post-doctoral researcher who studies bees and pollination ecology, and has recently begun a suite of studies on the island to identify who the pollinators are, what plants they are pollinating, and how important those pollination services are to the plants. Some of these plants are threatened or endangered, and knowledge like this can make a huge difference for ultimately helping to prevent their extinction. (Check out Sheena on twitter @sheenabees).

Korie is a graduate student in Dr. Rankin’s lab, and truly the expert among us on all things San Clemente. Korie has worked on San Clemente Island as a field biologist with Soil Ecology and Restoration Group (SERG) for 5 years. She knows the plants by sight, and is primarily responsible for the eradication of argentine ants, Linepethima humile, from the entire island (this is the topic of her thesis).

The process of getting to the island is indeed exactly that. First, Sheena and I drove from Riverside to San Diego, where the navy base is. There are physical checkpoints, my own background check had been completed earlier, and Sheena has a special ID badge that identifies her as an authorized visitor. We park at the airport on base, drop off our luggage, check in and meet up with Korie. When our flight is called, we walk on to the tarmac, up the steps and into a small plane that could hold maybe 24 passengers. I’ve never been on a plane this small and I am anxious about turbulence and my sensitive stomach. Luckily everything stays down.

At the end of the short flight, the first thing that truly strikes me about the island is the caterpillars. There are so many caterpillars, literally everywhere.

On our first day of fieldwork, we surveyed areas throughout the eastern, mesic side of the island for Castilleja grisea through the overcast morning and into the afternoon. Castilleja grisea is commonly known as San Clemente Island Indian paintbrush. It was historically very rare and listed as a federally endangered species.  It was recently downgraded to a threatened species due to increased population size and reduction in threats. Management efforts to support its recovery, including the removal of feral goats and pigs from the island, appear to have been successful. Today, Castilleja grisea is far more common than it once was.

At our first site, we found several clumps of our target plant quite quickly. Our next site proved to be a bit trickier. We walked across ridges, up and down hillsides, around canyons and inlets searching, unsuccessfully. We heard the barks and calls of an endemic Channel Islands fox, and soon after watched it trot along the opposite edge of a canyon from us until it was in clear view. It stopped for pictures and to watch us for a moment before heading off in the opposite direction.

We continued on our search for Castilleja grisea, following in the direction of the fox. Eventually, we found it! Yay!

We even saw large digger bees (Habropoda depressa) visiting the flowers.

We break for lunch at a perfect spot overlooking the ocean and an impressively steep canyon.

Later, Sheena and I visit a few more sites on the opposite side of the island. The western side is noticeably different. It’s drier and rockier, there is much more bare ground and less plant cover, little grass and so much cactus! Despite our best efforts to carefully avoid the cholla cactus all over the place, we end up with spines and brittle cladodes in our shoes, and sometimes on our pants and hands. We found the two populations we expected, and it is evident how challenging this arid environment is for Castilleja grisea. While we found populations of 50 – 200 individuals in the east, we found populations of 2 and 4 in the west.

The next day, we set up vane traps all over the island. Sheena has established a transect that runs north-south along the length of the island, to most effectively sample the diversity of pollinators there. We start at the southernmost end and work our way north all morning, hanging the traps from electric poles and garden hooks. The traps are yellow and blue; these two colors are the most attractive to insect pollinators like bees. The insects fly toward the trap, encounter the blue panels attached to the lid and fall, fly or crawl down into the yellow bowl where they are submerged into soapy water. Vane traps are left up for at least a whole day at a time, in order to ensure that pollinators flying at all times of day and night are sampled.

On my last day on San Clemente, we headed to the southernmost end of the island to visit populations of another of Sheena’s focal plants, Sibara filifolia.

These teeny tiny plants are endemic to San Clemente Island, Santa Catalina Island, and Santa Cruz Island, but they haven’t been found on Santa Cruz Island in about one hundred years.  This species is federally endangered and there are only hundreds to thousands of plants present each year depending on rainfall. Sibara filifolia is thought to have been driven to extremely low population sizes by the trampling impacts of grazing animals, similar to Castilleja grisea. Sheena set up a field experiment using naturally occurring individuals to determine whether pollination increases the fitness of these plants (this can be measured in multiple ways, including greater seed set, greater seed mass or greater seed viability). She used small fabric “tents” to exclude pollinators from being able to visit experimental individuals, while leaving neighboring individuals out in the open.

While we were there, Sheena collected the mature fruits of pollinator-excluded and pollinator-allowed plants to compare them back at the lab.

By late morning, it’s time for me to pack up and get ready to head home. A few days of work on the island was fun and went by quickly, it was a fantastic place to visit. Sheena drops Korie and me off at the airport for our flight; she stays on island for the remainder of the week to continue fieldwork. Once back on mainland California, Korie takes me to a great taco truck in San Diego.

I order too many fish tacos, they are delicious and I am quite full. It has been a great weekend.