Species and Ecology of Lagunita

Table of Contents

• Like a Vernal Pool: Dramatic Changes from Wet to Dry
• Species Interactions
  • Aquatic Predation
  • Swimmer's Itch Parasite Life Cycle
  • Ground Squirrels: Important Prey and Ecosystem Engineers
  • Bugs and Plants
  • Living Soil
• Year-in-the-Life Species Fun Facts
• Species Lists

Like a Vernal Pool: Dramatic Changes from Wet to Dry

Lagunita is a heavily managed wetland where water pools during years with sufficient rainfall and dries over the summer months. As a result, Lagunita supports many of the species endemic to California’s vernal pools. A vernal pool, is a type of wetland that fills with rainfall over the winter and spring and completely dries up over the summer.  In years with low rainfall, vernal pools may not fill with water at all. 

Though Lagunita may look very different when it is wet versus when it is dry, it remains a vibrant ecological community regardless of water level. In fact, most species at Lagunita are present year round, and are well adapted to change their behavior between seasons. Species evolved in vernal pools have unique adaptations that allow them thrive in wetlands with dramatic changes in water availability.

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Species Interactions

Aquatic Predation

Great Blue Herons (Ardea herodias) are wetland birds that can hunt in the water of Lagunita. (During the dry season, they forage for pocket gophers and other small mammals and reptiles in the grassland.)

California tiger salamander (Ambystoma californiense) larvae are completely aquatic, developing salamanders. They have gills, and look a bit like Axolotls. They prey on smaller aquatic organisms that fit in their mouths. Read fun facts about amphibian larvae below.

Sierran chorus frog (Pseudacris sierra) tadpoles are completely aquatic, developing frog larvae. They are a very important and abundant source of food for other aquatic species, including California tiger salamander larvae. Read fun facts about amphibian larvae below.

Fairy shrimp (Linderiella occidentalis) are small invertebrates that have an aquatic adult stage. They are dormant in cysts (like eggs) in the soil during dry times, but once there is enough pooling water, they hatch and develop in the water. Fairy shrimp are an important food source for other species, including California tiger salamander larvae. Read fun facts about fairy shrimp below.

Swimmer’s Itch Parasite Life Cycle

“Swimmer’s Itch” is a rash that is caused by parasites in the family Schistosomatidae. These parasites have a multi-host life history strategy.

Mallard ducks (Anas platyrhynchos) and other waterfowl can be infected by the swimmer’s itch parasite when the parasite burrows into the skin of their feet.

Parasite eggs in poop of infected waterfowl sink through Lagunita’s waters.

Miracidia hatch from the parasite eggs. In this life stage, the swimmer’s itch parasites are free swimming and able to infect snails.

Acute bladder snails (Physella acuta) and other aquatic snails can be infected by the miracidia and become the next host for this parasite. The parasite develops within the snail until it is released back into the water as cercariae.

Cercariae are free-swimming parasite larvae. They can restart the life cycle by infecting waterfowl, or they may burrow into human skin, causing swimmer’s itch rash.

Ground Squirrels: Important Prey and Ecosystem Engineers

California ground squirrels (Otospermophilus beecheyi) can be prey for many predators at Lagunita, including coyotes, Pacific gopher snakes, and Red-tailed Hawks. They also perform an important role as an ecosystem engineer, meaning their behaviors create structures that other organisms use to survive. California ground squirrels are compulsive hole builders and maintainers. They build so many holes that there are plenty left over for other species–such as salamanders and toads–to use as shelter.

Coyotes (Canis latrans) are important predators in Lagunita’s ecosystem. While it is important to stand back from coyotes and respect their space, they are very easily scared away by humans and loud noises. Stay safe by keeping dogs on leash and clapping your hands if one is near you.

Pacific gopher snakes (Pituophis catenifer catenifer) are non-venomous, meaning they don’t inject poison with their bite. Instead, they kill their prey through constriction, meaning by suffocating their prey by wrapping them tightly or pressing them into the ground.

Red-tailed Hawks (Buteo jamaicensis) can be seen circling above Lagunita, searching for prey. They have an identifiable cinnamon-red tail. Read fun facts about Red-tailed Hawks below.

California tiger salamander (Ambystoma californiense) adults seek refuge in underground burrows when it is dry. They seek out any refugia with moisture and temperature conditions that they prefer, such as in holes made by small mammals (including California ground squirrels), in small cracks and cavities in the soil, and underneath logs.

California toad (Anaxyrus boreas halophilus) adults also use holes made by small mammals to stay cool, wet, and safe. Read fun facts about California toads below.

Bugs and Plants

Narrow leaf milkweed (Asclepias fascicularis), like other native plants at Lagunita, is adapted for the dramatic changes in water levels that vernal pools provide. Narrow leaf milkweed blooms in the summer through fall, when Lagunita is completely dry. During wet and cool times of year, this plant is dormant and looks like a thin stick in the soil.

Monarch butterfly (Danaus plexippus) larvae live and feed on the narrow leaf milkweed plant. Milkweeds are host plants for monarch butterflies, meaning monarch caterpillars use milkweed species as their exclusive food source to survive and develop into adult butterflies.

Adult tarantula hawks (Pepsis) are parasitic wasps that lay their eggs inside of tarantulas. Their developing larvae consume their host. As adults, tarantula hawks eat nectar. The narrow leaf milkweed is one of the few plants that can provide these wasps with nectar late into the fall.

California ebony tarantula (Aphonopelma eutylenum) males can be seen migrating during the fall, in search of a mate. Read fun facts about California ebony tarantulas below.

Living Soil

Many organisms live in the soil at Lagunita. During the dry season, many invertebrate species are lying dormant, waiting for the next rainfall.

Fairy shrimp (Linderiella occidentalis) cysts are similar to eggs, and are the dormant form of fairy shrimp that live in the soil during dry seasons and years. If the soil remains dry, they can stay in cysts for multiple years. Read fun facts about fairy shrimp below.

Swimmer’s Itch Eggs also wait in the soil for the next time that Lagunita holds water.

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Year-in-the-Life Species Fun Facts

Fairy Shrimp

Linderiella occidentalis

Fairy shrimp seem to magically appear in seasonal bodies of water like Lagunita. Though they only live about 90 days, they lay eggs called cysts, which can last decades. Once cysts have been laid, they sink to the bottom of the vernal pool and begin a dormant stage called diapause. Diapause makes them virtually indestructible. They can survive extreme drought conditions, heat, and even the freezing cold of Antarctica where they have been found in melt ponds. Once the wet season arrives, some of the cysts hatch fully developed fairy shrimp, while others remain dormant. This means that in places like Lagunita, a huge bank of dormant fairy shrimp is always present. There are over 300 species of fairy shrimp, the one at Lagunita being called Linderiella occidentalis. They are an important food source to waterfowl and amphibian larvae. 

Read the Fairy Shrimp Year-in-the-Life sign

California Toad

Anaxyrus boreas halophilus

California toads are a subspecies of the Western toad, which is widespread across the Western U.S. They can live up to 10 years, reaching sexual maturity between 2-5 years of age. During the breeding season, a female can lay thousands of eggs in long jelly-like strings near the water’s edge. This is the only time of year you may see them out and about, walking, rather than hopping. Winters are spent in the burrows of ground squirrels and gophers, evading the cold. 

Read the California Toad Year-in-the-Life sign

Amphibian Larvae

California Tiger Salamander (Ambystoma californiense), Sierran chorus frog (Pseudacris sierra), and California Toad (Anaxyrus boreas halophilus)

During the wet season of the vernal pool, Lagunita is full of amphibian larvae, from Pacific tree frogs to California toads. Some larvae compete with each other, like the California tiger salamander, who preys on the larvae of its own species when other food can’t be found.  Different species can be distinguished from each other at this early age by physical features. The eyes of Pacific tree frogs, for example, are set on the edge of the head, while the eyes of the California toad are located on the top of the head. The larvae of tiger salamanders develop distinct, feathery gills. Egg clutches look different among the species, as well. Tiger salamanders lay individual eggs, Pacific tree frogs lay globs of multiple eggs, and California toads lay long strings of thousands of eggs.

Read the Amphibian Larvae Year-in-the-Life sign

Coastal Tidy Tips

Layia platyglossa

Tidy tips are a native species of wildflower that are part of the sunflower family. They prefer drier soils, so at the end of spring, they burst from the ground like bright little stars around vernal pools that have begun to dry. Besides brightening the scenery with a yellow pop of color, they are also an important source of nectar for the endemic Bay Checkerspot butterflies, an endangered species in the area. 

Read the Coastal Tidy Tips Year-in-the-Life sign

Killdeer

Charadrius vociferus

Possibly the cutest seasonal residents of the vernal pool are killdeers, who have a two-syllable, high-pitched shrill that enhances their charm. You can spot these tiny birds searching for worms and other small invertebrates in shallow water, where they will stand on one foot, shaking the other to disturb the water and catch their prey. During the breeding season, they lay clutches of 4-6 eggs. The eggs are only about 1.5 inches long and are laid directly on the ground in small depressions. These nests are camouflaged expertly with stones and twigs that blend into the speckled pattern of the eggs. Since they are small and well-disguised it's important not to walk off trail where you may accidentally step on a killdeer nest.

Read the Killdeer Year-in-the-Life sign

Red-Tailed Hawk

Buteo jamaicensis

The red-tailed hawk is one of the most common raptor species across North America, and can be found in a wide variety of ecosystems including deserts, grasslands, coastal areas, and even densely populated urban areas like New York City. With eyesight 7 times sharper than the human eyes, they perch on high trees and telephone poles waiting for subtle movements of ground squirrels and other small mammals below. When diving down for the kill, they can reach up to 120 mph, while in normal flight, they soar at 20-40 mph. Red-tailed hawks mate for life. Their courtship, which begins in the spring, consists of an aerial performance where the two hawks soar together while the male repeatedly flies high above the female, then dives back down, lightly touching its mate each time.

Read the Red-Tailed Hawk Year-in-the-Life sign

Black-Tailed Jackrabbit 

Lepus californicus

Born fully-furred and with eyes wide open, the black-tailed jack rabbit is only nursed for a few days before it is ready to forage on its own. From then on, it lives year-round in a one-square mile area. This means the jack-rabbits you spot on campus are lifelong residents of the Stanford community. These agile animals can run at speeds of up to 40 mph (64 kmh) and jump up to 10 feet. They move from shrub to shrub eating grasses and forbs, and will freeze in an eerie stance when approached in the open as an attempt to evade predation. 

Read the Black-Tailed Jackrabbit Year-in-the-Life sign

Intergrade Gartersnake

Common gartersnake (Thamnophis sirtalis) intergrade between two subspecies: the San Francisco gartersnake (Thamnophis sirtalis tetrataenia) and the red-sided gartersnake (Thamnophis sirtalis infernalis) 

The gartersnakes found at Lagunita are a cross between two subspecies: the endangered San Francisco gartersnake and the red-sided garter snake. For that reason, it is referred to as an integrase species. Like most garter snakes, this intergrade species needs both freshwater and dry upland areas to survive. They go down to the water to feed on frogs and other amphibians and return to dry grasslands to find cover or hibernate. During breeding season, females can give birth to anywhere from 6 to 30 live young. 

Learn more about this intergrade gartersnake at Stanford
Read the Intergrade Gartersnake Year-in-the-Life sign

Acorn Woodpecker

Melanerpes formicivorus

The acorn woodpecker is a specialist species of oak woodlands that lives year-round in California. They have a fascinating social structure, in which groups of around 5-6 birds live, breed, and defend their food together for life. During the breeding season, eggs laid by the females are incubated and cared for by every individual in the group. In addition to taking shifts parenting the young, they also take turns defending their “granary trees”. One granary tree can have over 50,000 holes where multiple generations of a single group have stored acorns. 

Read the Acorn Woodpecker Year-in-the-Life sign

California Ebony Tarantula

Aphonopelma eutylenum

Ebony tarantulas live most of their long lives in underground burrows that they cover with a mat of their own silk. The silk mat is used to sense small invertebrates that unknowingly walk across it on the surface, alerting the spider of the presence of potential prey. While they are deadly to small insects, to humans they are no threat to and are quite docile when handled.  The only time you might see a tarantula on the surface is during mating season from mid-September to mid-October, when male tarantulas leave their dwelling and migrate in search of a female’s burrow. Male tarantulas mate once, after they’ve reached sexual maturity at around 8-12 years old, and die soon after. Females, on the other hand, can live up to 25 years. 

Read the California Ebony Tarantula Year-in-the-Life sign

Chestnut-Backed Chickadee

Poecile atricapillus

The Chestnut-backed Chickadee is a curious species of bird that won’t hesitate to approach you in search of food. They eat a wide variety of seeds, fruits, and nuts, and can become quite tame and comfortable with humans who feed them. The chirp of a chickadee breaks down to six syllables that forms the basis of an extensive chirping language. This language includes warning calls where they will increase the number of “dees” in their chirps based on the severity of the imminent threat and the location of the threat.

Read the Chestnut-Backed Chickadee Year-in-the-Life sign

Hooded Merganser

Lophodytes cucullatus

The Hooded Merganser’s iconic crest makes them distinct from the rest of the waterfowl of the vernal pools. This species is sexually dimorphic, meaning the females and males have different appearances. While the crest of the male is black and white, the female flaunts cinnamon colored plumage on her head. They have specialized eyesight for underwater vision, in order to dip below the surface and hunt aquatic insects and fairy shrimp.

Read the Hooded Merganser Year-in-the-Life sign

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Species Lists

Working Lagunita species lists (updated October 2024)

please contact us if you see anything missing or inaccurate

• lagunita_species_list.pdf (262.66 KB)

• full_lagunita_species_list.xls (269.5 KB)

• full_lagunita_species_list_csv.txt (53.19 KB)

• Lagunita species lists by taxa:
  • lagunita_amphibians.pdf (52.95 KB)
  • lagunita_birds.pdf (36.86 KB)
  • lagunita_fungi.pdf (32.24 KB)
  • lagunita_invertebrates.pdf (43.83 KB)
  • lagunita_mammals.pdf (21.08 KB)
  • lagunita_plants.pdf (66.9 KB)
  • lagunita_reptiles.pdf (17.92 KB)
  • other_lagunita_species.pdf (23.23 KB)
• Note: Any historic records of fish in Lagunita are incidental and were due to water diversion methods that are no longer in use. No persistent population of fish exist in Lagunita.

Stanford property species lists can be found here

Learn more about biodiversity at Stanford here

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