Briones Regional Park Field Trip,
February 16, 2006

Scorpions were common under logs and rocks in the park. Here Jesse shows one that was slow and docile on this cool morning.

To investigate the diversity of salamanders in the East Bay, Richmond High went on a field trip to Briones Regional Park in Contra Costa County. Before our trip, we examined museum specimens of the species found in the East Bay to create a key. We then set up our study questions: Do salamanders prefer logs or rocks as cover? Do larger cover objects host more salamanders than small? Are larger salamanders found under larger cover objects?

Ryan demonstrates to Erick how to measure the snout-vent-length (SVL) of a newt. The SVL is a good measure of salamander and lizard size because it ignores the tail, which could break off.

When we made it to Briones the next week, students had no problem identifying the salamanders correctly. In all, we saw four species. The slender salamander (Batrachoseps attenuatus) was the most common, and we found them both in the woodlands and out in the open grasslands. The much rarer and larger ensatina (Ensatina eschscholtzii) was found near a small wetland, where the soil was very saturated. Breeding California newts (Taricha torosa) were found by the pond and by the wetland, where we also found their relative, the rough-skinned newt (Taricha granulosa).

Like all scientists, RHS students shared their findings by making oral presentations back in the classroom. Working in pairs or singly, students analyzed the data using Microsoft Excel. They then made bar graphs and scatter plots to show how cover type and area relate to the size and abundance of salamanders. Then, the students presented their findings to each other, and decided whether to accept or reject our hypotheses.

Salamander ID worksheet (pdf) — based on toe shape and number.
Salamander dichotomous key (pdf) — identification based on a series of yes/no questions.

Erick, Stephanie, and Rocio examine salamander specimens from the Museum of Vertebrate Zoology. Students determined which morphological traits — such as number and shape of toes, or the presence of a tail constriction — distinguish between the species found at Briones Regional Park. The students then used these distinguishing traits to make a dichotomous key to identify salamanders in the field.		Before beginning the study, students made observations in their field notebooks about the habitat and weather conditions at Briones Park. Most of the habitat was grassland and oak woodland. Students who went on the Sierra field trip recognized the oaks as coast live (Quercus agrifolia) and blue oak (Q. douglasii) species. Although the beautiful sunny weather made for an enjoyable field trip, we were concerned that the lack of rain and fog would keep amphibians away.		Turning over logs revealed far more biodiversity than just salamanders! Millipedes, beetles, centipedes, termites, and spiders share the same habitat as salamanders. Here, Esme notices the almond-like odor of a millipede in Ryan's hand. Although the scent is sweet, it comes from cyanide, a poisonous compound that protects the slow-moving millipede from predators.
Ms. Robinson showed a southern alligator lizard (Elgaria multicarinata) to the class. The keeled scales, lateral fold, head shape and color pattern distinguishes this species from the other lizards we came across, such as western fence lizards (Scleroporus occidentalis) and western skinks (Eumeces skiltonianus).		Erick shows Yoshi and Ricky the distinctive blue tail of the western skink (Eumeces skiltonianus). Skinks are much quicker than other lizards, and are much harder to catch!		Ricky caught an adult California newt (Taricha torosa). Newts use this pond to breed and lay eggs. We observed many egg masses in the pond. Although newts were not common in the pond on our trip, their bright orange bodies made them easy to see from the shore.
Students learned how to use a pesola to weigh things in the field. Jesse and Ricky weighed the newt Ricky caught in the pond.		The abiotic environment can affect biodiversity, so students made sure to describe the environment in as many ways as possible. Here, Jesse measure the water temperature of the pond where we found the newts.		Pacific tree frogs (Hyla regilla) were very common around the pond. Although some students were squeamish about touching a frog at first, their curiosity overcame the aversion and they learned how to handle live animals without harming them.
To investigate the effect of cover type and area on salamander diversity, students measured the size of logs and rocks, and measured all salamanders they found underneath. Here, Rocio, Yoshi, and Esme measured the surface area of a log.		When we found a salamander, we first identified it to species and then measured its size. Here, Rafi hands Esme a slender salamander (Batrachoseps attenuatus) so she can measure the snout-vent-length (SVL). Rocio has a bag ready to measure the salamander's weight with a pesola scale.		All scientific research requires diligent note taking. Steph helped her group out by recording cover type, length, and width for each log or rock sampled. When we found a salamander, she recorded the species, the snout-vent-length, and weight.
Slender salamanders don't weigh very much, so getting an accurate reading can be tricky. Rocio makes sure to guard the scale from the wind, which can interfere with the reading.		Ensatinas (Ensatina eschscholtzii) were among the largest and most striking salamanders we found. The orange coloring may help them mimic newts, which are highly poisonous and avoided by most predators.		Back at Richmond High, students learned how to use Microsoft Excel to analyze and graph data. Here, Elizabeth creates a plot to show the correlation between the number of salamanders and the size of the logs and rocks under which they were found.
Yoshi shows us her graph. It seems that cover area does not have a strong relationship with salamander snout-vent-length.		Learning how to convey scientific data is an important goal of the GK12 program. RHS students used created graphs to make short presentations to each other about their findings. Here, Steph and Jesse show how salamander mass relates to cover area.

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