week 1: Scripps Coastal Reserve

We visited the Scripps Coastal Reserve “Knoll” for our first field trip of the quarter. Some of the most common shrubs are the drought-deciduous ,Artemisia californica (California Sagebrush) and Encelia californica (California Brittlebush). These two species, both in the Asteraceae (sunflower) family, look rather different but have the same strategy of dropping their leaves when the weather turns hot and dry. A shrub with a completely different strategy is Rhus integrifolia (Lemonade Berry). This plant has very deep roots that allow it to maintain access to water throughout the year and evergreen, sclerophyllous (thick and leathery) leaves to resist losing that water.

We also saw the shrub Baccharis pilularis (Coyote brush). This species is diecious, which means it has male and female flowers on different plants. The female plants have fluffy white pappus that helps the seeds to float away on the breeze. I had a surprisingly hard time finding the galls that are usually very common on these plants, but we eventually found both Rhopalomyia californica (Coyote Brush Bud Gall Midge) and Puccinia evadens (Coyote Brush Rust). We didn’t look long enough to find the third gall that is common on this species, Gnorimoschema baccharisella (Coyote Brush Stem Gall Moth), but I’m sure there was some out there.

I passed around the very large seed of the perennial herb Marah macrocarpa (Chilicothe on iNat, but commonly called Wild Cucumber). While I was correct in saying that these seeds are dispersed by mammals, I incorrectly stated that packrats such as Neotoma macrotis (Big-eared Woodrat) are important dispersers. If a packrat cached a seed, it would not have much of a chance of germinating, as they store their food within elaborate nests built out of sticks above the ground. Mammals that are more helpful in dispersing these large seeds are ones that store their seeds in burrows, such as Peromyscus (North American Deer Mice). Other vertebrates such as Aphelocoma californica (California Scrub-Jay) are also important dispersers of this species (Borchert 2004).

We observed the presence of a couple species indirectly thanks to the sharp-eyed students who pointed them out. We saw the lid of a Bothriocyrtum californicum (California Trapdoor Spider). You can watch a video of one capturing prey here (but don’t blink!): https://youtu.be/9miAnM9yCjs?t=109
Trapdoor spiders can be incredibly long-lived, as was noted when the oldest observed trapdoor spider died at the age of 43 in 2016. The study of this spider lasted so long that the original researcher handed over the annual monitoring of the burrow over to her graduate student when she retired. https://www.publish.csiro.au/pc/PC18015
Scientific studies are often limited in time, so I love the persistence these researchers demonstrated in showing up year after year to track this spider.

We also saw some large tracks that we determined were from a Canis latrans (Coyote) and discussed how to distinguish the tracks from a Lynx rufus (Bobcat). I speculated about how likely it might be that bobcats commonly use the Scripps Coastal Reserve. While SCR is the right type of habitat for bobcats, increased urbanization and habitat fragmentation makes life difficult for this species, and I didn’t know for sure how often bobcats actually make it to the Knoll. Shortly after our class, I received an email from my ESYS student who is monitoring wildlife at SCR with a trail camera. She observed a bobcat in the reserve just last month! https://www.inaturalist.org/observations/146384257
Even though the photo is a little difficult to make out, you can definitively identify it as a bobcat because of the distinctive white patches on the ears.

We also talked about the diversity of Opuntia. Here is one source for the number of Opuntia species recognized by indigenous taxonomies, and here is the link to the guide created by @andyjones1

Publicerat 13 januari 2023 18.31 av kuyeda