Ecological Relationships

ECOLOGICAL RELATIONSHIPS

Food webs and other ecological relationships illustrated in ink and watercolor

Spotted Owls among the Firs

Throughout the mature conifer forests of North America, Northern Spotted Owls have been impacted by both deforestation and the arrival of Barred Owls (Strix varia) across their range. However, in Marin County, the Spotted Owls remain relatively stable to date, likely due to large areas of protected habitat throughout the county, and low numbers of Barred Owls.

This piece was created after an artist-in-residence at Point Blue Conservation Science’s Palomarin Field Station in West Marin County. Through art and science collaboration, 7 Ravens Studio and Point Blue hope to engage more people in conservation action.

Garter Snake among the Brambles

San Francisco Garter Snakes (Thamnophis sirtalis tetrataenia) and California Red-legged Frogs(Rana draytonii) are two endangered species that call the Bay Area home. Both tied to freshwater, they are most impacted by the decline of suitable habitat in a heavily developed region. Still, they manage to hold on in pockets of habitat strewn across a landscape populated with more familiar species like Poison Oak (Toxicodendron diversilobum), California Blackberry (Rubus ursinus), Barn Swallows (Hirundo rustica), California Darner dragonflies (Rhionaeschna californica), and mayflies (Baetis sp.).

Oystercatchers in the Tidepools

In some places, the rock surfaces around tidepools look black from a distance. Look closer and you will see that the black is actually the deep indigo of California Mussel colonies or a dense coat of marine algae that are actually green, purple, red, gold, or brown. Every pool teems with life - including small molluscs we know as Purple Olivella and wildly colored Anenomes (here A. sola). The piercing calls of Black Oystercatchers can be heard over the crashing waves and their orange bills and yellow eyes set against nearly black plumage are a striking sight as they hunt for food among the rocks.

Orcas near the Farallones

White Sharks (Carcharodon carcharias) and Orcas (Orcinus orca) both occupy a position as apex predators in their ocean habitat. When sharks move out of an area to avoid orcas, that impacts the prey the both hunt - here, Northern Elephant Seals (Mirounga angustirostris). The prescence or absence of apex predators also impacts the foraging strategies, which are different for male and female Elephant Seals. Where males forage near the sea floor along the continental shelf, relying on species like Silvergray Rockfish (Sebastes brevispinis) and Pacific Hake (Merluccius productus), females forage in the open ocean, relying on species like Humboldt Squid (Dosidicus gigas). Small, bioluminescent Blue Lanternfish (Tarletonbeania crenularis) are prey for many species, including both squid and seals, as they migrate vertically in the water column.

Whipsnakes among the Fairy Lanterns

In the oak woodlands of Mount Diablo, Feralia februalis caterpillars munch on Blue Oak (Quercus douglasii) leaves while an Oak Titmouse (Baeolophus inornatus) chatters noisily nearby. Rocky outcrops provide habitat for Western Fence Lizards (Sceloporus occidentalis), commonly known as "blue-bellies" for their turquoise and indigo undersides. The stealthy and lightning-fast Alameda Whipsnake (Masticophis lateralis euryxanthus) may make a quick meal of a basking lizard. In cooler, shadier places, the plant community shifts to include a variety of moisture-loving plants. Here an astute observer may be rewarded with a glimpse of the Mount Diablo Fairy Lantern (Calochortus pulchellus). This distinctive yellow-green lily with elegant 'wings' atop its drooping head is only found on the slopes of Mount Diablo and blooms for just a few weeks each year.

Slugs in the Redwoods

Banana slugs (Ariolimax californicus) live in close association with Coast Redwoods (Sequoia sempervirens), along with a variety of moisture-loving species. Their only known predator is the California Giant Salamander (Dicamptodon ensatus), a unique species limited to the coastal forests and fresh water marshes between Santa Cruz and Mendocino Counties. Western Azalea (Rhododendron occidentale) enjoys the fog drip provided by life in a redwood canopy and Fetid Adder's Tongue (Scoliopus bigelovii) is an early-blooming wildflower limited to mossy, damp slopes in the deep shade of the forest. The Hermit Thrush (Catharus guttatus) song is a hauntingly beautiful whistle that carries through the understory, providing a soundtrack to the thrum of life beneath these iconic trees.

Salmon in the San Lorenzo

In the wet, rocky places up in the far reaches of the San Lorenzo River watershed lives the Santa Cruz Black Salamander (Aneides flavipunctatus niger). As springs and seeps grow into streams, Big Leaf Maple (Acer macrophyllum) provides shade as the American Dipper (Cinclus mexicanus) dives for aquatic insects in the flowing water. Further downstream, Arroyo Willow (Salix lasiolepis) leaves flash grey and green as they sway in the breeze. In late spring, the Eyed Sphinx Moth (Smerinthus cerisyi) emerges to mate and lay eggs on the willow leaves. Unlucky adults may become a meal for Coho Salmon (Oncorhynchus kisutch) who are making their way back to their natal waters to breed after maturing in the open ocean.

Peregrines in the Baylands

Peregrine Falcons (Falco peregrinus) have come back from the brink of extinction and are now even using urban buildings and bridges for their nest sites. Peregrines prey on a wide variety of birds, including the abundant and invasive European Starling (Sturnus vulgaris) as well as the endangered California Least Tern (Sternula antillarum browni). California Least Terns populations are in decline primarily because of threats at their nesting sites, where development destroys important habitat and feral cats or birds like the American Crow (Corvus brachyrhynchos) eat eggs and young birds. Least Terns feed almost exclusively on small fish, here represented by Topsmelt (Atherinops affinis), making them indicators of the health of aquatic ecosystems.

Wrens in the Hazelnuts

This piece is inspired by an experience of listening to Pacific Wrens (Troglodytes pacificus) sing in the California Hazelnuts (Corylus cornuta) outside my window on the edge of the redwood forest. The forest edges are also inhabited by California Bay Laurel (Umbellularia californica) and Tanoak (Notholithocarpus densiflorus) trees. The Dusky-footed Woodrat (Neotoma fuscipes) uses laurel leaves to fumigate its huge stick nests. The aromatic compounds in the laurel leaves discourages pests in the woodrat's home, which it can use over many generations.

Foxes at the Meadow's Edge

If you sit quietly along the edge of a grassy meadow in the Santa Cruz Mountains, you might be surrounded by Giant Chinquapin (Chrysolepis chrysophylla) and Yerba Santa (Eriodictyon californicum). On warm spring days, watch for a small butterfly the color of toasted marshmallows flitting about. This is the Golden Hairstreak (Habrodais grunus), looking to lay it's eggs on the chinquapin. You might also notice a small brown mammal that looks like a large mouse. If you look closely, you'll notice it has a short tail and small ears - this is a Meadow Vole (Microtus californicus), the favorite food of both the Long-tailed Weasel (Mustela frenata) and White-tailed Kite (Elanus leucurus). Kite populations are closely tied to the abudance or scarcity of Voles, just as the abundance of Long-tailed Weasel is tied to the presence or absence of Grey Foxes (Urocyon cinereoargenteus).

Kestrels in the Sandhills

The Sandhills of the Santa Cruz Mountains include two habitats that are home to organisms that live nowhere else on earth. Silverleaf Manzanita (Arctostaphylos silvicola), Santa Cruz Wallflower (Erysimum teretifolium), and Ben Lomond Spineflower (Chorizanthe pungens var. hartwegiana) are all specially adapted to live in the sandy, well-drained, and sparsely vegetated soils found in this otherwise volcanic mountain range. The mottled grey and tan Zayante Band-winged Grasshopper (Trimerotropis infantilis) is perfectly camoflaged until it flies from its sandy perch. Then you might catch a glimpse of its bright blue hindlegs and pale yellow wings with a curved dark brown band. The Mount Hermon June Beetle (Polyphylla barbata) looks similar to more common June Beetles but is distinguished by its reddish color and limited range. Both of these federally endangered insects may be favorite meals for the American Kestrel (Falco sparverius).

Beetles in the Coastal Prairie

Ohlone Tiger Beetles (Cicindela ohlone) are only found in a few pockets of Coastal Prairie in Santa Cruz County. They need disturbance in the prairie to provide the open ground they rely on for breeding habitat. But a bright green beetle sitting out in the open may be easy prey for a hungry Northern Flicker (Colaptes auratus). Flickers eat mostly on the ground - consuming beetles, earthworms, pill bugs, and other invertebrates. A healthy coastal prairie is home to a wide variety of native plants, including the state flower - California Poppy (Eschscholzia californica) and the state grass - Purple Needlegrass (Nassella pulchra). Butter and Eggs, a relative of the paintbrushes and owls clovers, also share the prairie habitat.

Grouse in the Sagebrush Sea

The sagebrushes (Artemisia sp.) that are the dominant shurbs across much of the Great Basin are an important source of food and shelter for the Greater Sage Grouse (Centrocercus urophasianus). During the late summer, Sage Grouse fatten up on insects, represented here by the Hairy Bear Scarab Beetle (Paracotalpa granicollis). During the winter, Big Sagebrush (Artemisia tridentata) and other sagebrush species, are the primary source of food for the birds. Paintbrush (Castilleja chromosa), Sagebrush Lizard (Sceloporus graciosus) and White-tailed Antelope Squirrel (Ammospermophilus leucurus) also share this arid landscape. The increased frequency and intesity of wildfires, fueled by invasive non-native grasses, continues to strain the resiliency of this unique western ecosystem.

Pikas among the Bristlecones

High in the White Mountains of California stand the world's oldest non-clonal trees, the Bristlecone Pine (Pinus longaeva). The pines provide food and shelter to a raucous bird known as Clark's Nutcracker (Nucifraga columbiana). Because Bristlecones are particularly sensitive to variances in precipitation, they provide an excellent record of long-term climatic conditions. Bristlecones share their high-elevation homes with a number of other species that are uniquely adapted to life shaped by particularly harsh conditions. This includes the American Pika (Ochotona princeps), a relative of rabbits and hares, who has a low tolerance for warm daytime temperatures. Suitable Pika habitat is limited to small, disconnected habitat "islands" as they retreat to higher elevations in response to climate change.

Nuthatches in the Jeffrey Pines

Jeffrey Pine (Pinus jeffreyi) needles are eaten by caterpillars of the Pandora Moth (Coloradia pandora). In turn, the caterpillars are food for the White-breasted Nuthatch (Sitta carolinensis tenuissima). The moth pupae ("piagi") and Jeffrey Pine nuts are traditional foods for the indigenous people of the Eastern Sierra.

In the Fall of 2019, as I was preparing for Open Studios, I revisited a few of my older food web drawings and decided to add some color. This one was a natural choice as one of my favorites. I’ve been very inspired by the ecosystems of the Eastern Sierra over the past few years and this piece pays special tribute to the pure stands of Jeffrey Pine that are just south of Mono Lake.

Pupfish in the Owens Valley

Introduced species such as trout and bass have decimated pupfish populations in the Owens River. These little pupfish do not need any special conditions to survive, yet they are extirpated from their traditional home in the Owen’s River and are barely hanging on in isolated locations in the Owen’s Valley of California. Pupfish share habitat with a wide variety of other species that live here on the edge of the Great Basin: Grey Willow, Desert Spiny Lizard, and Mourning Cloak butterfly.

Shooting Stars in the Wet Meadows

Inspired by my residency in the Plumas National Forest in 2018, this piece focuses on the creatures that inhabit the wet meadows of the Sierra Nevada and Cascade Mountain ranges. Coming upon a wet meadow in the dry forests of the Western U.S. is similar to finding an oasis in the desert. A unique community of plants and animals depends on the year-round water there. Leopard Lillies (Lilim pardalinum) and Shooting Stars (Primula jeffreyi) both require wet places to grow. Sierra Nevada Blue Butterfly caterpillars (Plebejus podarce) eat Shooting Stars and Hunt's Bumblebee (Bombus huntii) pollinates many different flowers. Sierran Chorus Frogs (Pseudacris sierra), Mountain Garter Snakes (Thamnophis elegans elegans), and Tree Swallows (Tachycineta bicolor) are each both predator and prey in this complex ecosystem.

Thrashers in the Ceanothus

California's foothills are blanketed with vast swaths of shrubbery, also known as chaparral. This dense growth provides habitat for a number of animals. Buck brush (Ceanothus cuneatus) is one of our dominant chaparral shrubs and it is eaten by caterpillars of the Ceanothus Silk Moth (Hyalophora euryalus). California Thrashers (Toxostoma redivivum) use their long, curved bills to dig for food in the leaf litter beneath shrubs and perch atop them to sing.

In 2019, I revisited some of my older food web drawings and rendered them in color. I love how adding color really brings these images to life.

Prairie Falcons in the Grasslands

Although California Ground Squirrels (Otospermophilus beecheyi) are often considered pests, they play an important role in the ecosystem. They disperse the seeds of native plants such as lupines (here - Lupinus nanus) and the acorns of Blue Oaks (Quercus douglasii). They also consume invasive plants like Erodium cicutarium. The ground squirrel is a major source of food for many predators, including Prairie Falcons (Falco mexicanus), a species of special concern in California. One of the threats to Prairie Falcons is the presence of rodenticides in the food web.

This is another piece I revisited for Open Studios in 2019. It was fun to rework this piece a bit to add a pop of color with the lupine flowers.

Herons in the Cattails

Great Blue Herons use a variety of habitats and consume a wide array of prey items including fish (here, the Three-spined Stickleback), mammals (here, the Western Harvest Mouse), and frogs (here, the American Bullfrog). While herons will hunt just about anywhere there is prey, they are closely associated with wetlands. In California, wetlands often include cattails growing in shallow waters.

Condors in the Ecosystem

California Condors (Gymnogyps californianus) play an important role in cleaning up the remains of a wide variety of species across the ecosystems of the Western U.S.. Along the Pacific coast, they consume dead sea mammals that wash up on the shore, like this California Sea Lion (Zalophus californianus). Inland, condors feast on the carcasses of many land animals, including Mule Deer (Odocoileus hemionus). And as both the birds and fish return to their historic ranges, condors may also feed on the remains of salmon (Oncorhynchus tshawytscha) after they spawn.

Plovers in the Dunes

Snowy Plover populations in California are struggling in part due to loss of dune habitat along the coast. Restoration of the dunes includes reintroduction of native plants (here: lupine, buckwheat, and sand verbena). These plants also provide important resources for other species like the Smith’s Blue butterfly, California legless lizard, and Globose Dune Beetle.

Willets in the Pickleweed

This painting was inspired both by my Artist-in-Residence at Elkhorn Slough and by Younger Lagoon, which is part of the UC Santa Cruz Natural Reserve System. As I continue to learn about the unique aspects of our coastal ecosystems, I’m coming to understand the important role that saltmarsh plays in protecting our coastline. In both Elkhorn Slough and Younger Lagoon, pickleweed is a key feature of the saltmarsh. And there is a huge number of species that occupy the various habitats that saltmarsh provides. The willets, shore crabs, anchovies, waterboatmen, and jaumea featured here are just a few.

Otters in the Slough

This design is inspired by my time as an Artist in Residence at Elkhorn Slough in March 2018. I had the great pleasure of observing Southern Sea Otters (Enhydra lutris) in the wild. I was able to spend time with researchers and scientists learning about the incredibly important role that otters play in both the Monterey Bay ecosystem and the Elkhorn Slough ecosystem.

In this piece, the focus is on the role of otters in the health of the eelgrass beds of Elkhorn Slough. Otters eat crabs, which reduces crab predation of sea slugs. Slugs feed on algae, which improves the health of the eelgrass beds. Eelgrass provides habitat for a variety of other organisms, including bat rays and English sole.

Otters in the Kelp

Another piece inspired by my time as an Artist in Residence at Elkhorn Slough! Out in the Monterey Bay, otters feed on a wide variety of organisms, helping to keep the kelp beds healthy and the ecosystem in balance. This piece includes a favorite otter food - Pacific Purple Sea Urchin (Strongylocentrotus purpuratus) - as well as the endangered Black Abalone (Haliotis cracherodii), Northern Kelp Crab (Pugettia producta), Blue Rockfish (Sebastes mystinus), California Sheephead (Semicossyphus pulcher), and Bat Star (Aserina miniata). All of these creatures (and many, many more!) share the beds of undulating Giant Kelp (Macrocystis pyrifera) that line the edges of the Monterey Bay.