UCR
BIOL X431.8: Natural
History of the Channel Islands
31 May 2013-2 June 2013
Kurt Leuschner, Instructor
Recommended Text: Schoenherr, Feldmeth and Emerson, Natural History of the Islands of California (1999)
Friday, 31 May 2013
Meeting in the breakfast room of the HI at 6PM. Introduction covering the Bight of California (roughly from Point Conception to San Diego) and some oceanography. Complex geology including volcanic origins and sedimentary layers as well. Brief discussion of continental versus oceanic islands including the concept of island biogeography introduced by Robert McArthur and E. O. Wilson who suggested “an equilibrium determined by the balance between immigration rates and extinction rates.”[1] Introduction to the SLOSS debate—the role of a single large island versus several small islands in “conserving biodiversity in a fragmented habitat.” For example, the largest island, Santa Cruz, has the most biodiversity. Moved on to methods of colonizing: 1) land bridge, 2) swimming or flying, 3) rafting (the most notable reported example being a live, but emaciated jack rabbit (Lepus californicus or bennettii) found floating on a 40x25 foot pelagic raft of giant kelp (Macrocystis pyrifera) near Lat. 33 degrees, 13 minutes N and Long. 118 degrees, 45 minutes W (defining the basin between Santa Catalina, Santa Barbara and San Clemente Islands), the latter being the closest island, but still 39 miles (62 km) “from the nearest point of the California coast” in August 1955,[2] 4) air flotation, 5) passive transport, and 6) vicariant transport. Brief discussion of likely animals which could be seen, given that there are about 1,000 possibilities including 12 endemic animals such as Santa Cruz Island Deer Mouse, the Anacapa Deer Mouse, and the Santa Cruz Scrub Jay (see role of AOU) and birds such as bald eagles, house finch, Bewick’s wren, orange-crowned warbler, logger head shrike (the SCI has only 13 but seems to be making a comeback) and plants such as the giant coreopsis. Then, the issue arose of island gigantism (and reasons for it such as more prey, better efficiency with water, especially retention, better dispersal and finally, fewer competitors) as opposed to insular dwarfism (and less resources, so you are smaller, no trees/cover so less places to hide). Note Cope’s Rule about organisms getting bigger over evolutionary time.
Field Notes:
Saturday, 1 June 2013
9AM departure on “The Island Adventure” with Island Packers with Laurie, Dede and Joel, as staff guides. Overcast—light coastal fog aka June gloom, no wind (in harbor, but a 20MPH head wind out in the channel), calm water. Sat on the starboard side, upper deck under the canopy as per Larry Loeher[3] suggestion. Birds: peregrine falcon (on mast in harbor), blue heron, western grebe, double crested cormorant, surf scooter, barn swallow, oyster tern, Brandt’s cormorant, California brown pelican, red-necked phalarope, Sooty Shear Water (Puffinus griseus), raven, pelagic cormorant, pigeon guillemot, and dolphins off the stern as we left the harbor.
Arrived at
11:30AM at Prisoners Harbor[4]
of Santa Cruz Island. High tide
will be 4PM. Cool, fog. Dr. Carey Stanton died on the island in 1987
and is buried in the island chapel yard.
An 1887 building made from local materials. Saw the endemic scrub jay. Trail upward with Joel as our guide toward
Pelican Bay: island buckwheat versus SCI buckwheat (with light/dark green
leaves), coastal sagebrush, spotted towhee (Pipilo
maculatus), agave, red gum eucalyptus, fennel, coyote brush, island morning
glory, giant coreopsis, more coastal sage, Northern flicker, monkey flower,
Live-forever (Dudleya cymosa), silver lupine and deer weed (both good nitrogen
fixers), manzanitas, oak (gargled trunks), acorn woodpecker, scrub oak,
lemonade berry, osprey, summer holly (red berries not to be confused with
toyon-- Heteromeles arbutifolia), bishop pine (tight cones), Ceanothus
(island lilac, purple berry seed pod), Humboldt’s lilies (Lilium humboldtii), old man’s beard (indicative of
good air quality), lizards (including western fence and side blotched),
hazardia, ironwood tree (something like 13 clones extant), and western fence
lizard (Sceloporus occidentalis).
Late lunch break with a good view; just after lunch at 2PM, medical evaluation
Joel (who is an RN as well!) of classmate by who lost her footing and tumbled
over the edge of the trail; small gash on right ear. 3PM arrival at large oak and have to turn
back before Pelican Bay, if we are to leave island today; maximum gain in
elevation was about 400 feet. In the
distance, we could hear the foghorn of a container ship, which is required to
sound it every two minutes. 3:47PM I saw
the island fox and pointed it out to Dede and Nance. Nance and I discussed the odd scat behavior
of the fox, which seems much more feline like, based our AB tracking
classes. 4:03 departure with a 5 foot
tide; discussion of binoculars--Kurt likes the 8x42 Vortex Crossfire and
suggested we might visit Optics4birding
in Irvine. The captain maintained a
steady 1850-1860 RPM on the way back to the dock. Dinner at Capriccio’s in downtown Ventura with Kurt and Nigel Hunter,
head of development for the East African Wild Life Society
who is in the US working on developing ideas on to disseminate “SWARA:
The Voice of Conservation in East Africa,” more widely.
Figure 1. US Coast Survey, 1854; engraving by J. A. Whistler
who lost his job for unauthorized inclusion of Western gulls in this image
Sunday,
2 June
9:20AM with fog—marine
layer, calm, 66 degrees. Under
way to Anacapa Island on the “Vanguard,” we saw three Mylar balloons (but
didn’t pick them up like the two we did yesterday), a couple of sea lions and
fourteen pelicans flying in a v-formation.
At the Arch by 10:40AM, landed at the East Anacapa Landing Cove, and at
11AM had an orientation about nesting behavior/dive-bombing of gulls (if they
are squawking, then keep walking!) and the 1932 buildings in the style of a
Mexican fishing village; early history includes a 1853 shipwreck and a 50 foot
beacon by 1912; 1938 established as a National Monument and then a National
Park in 1980. Nothing
very large on this island.[5]
The island is either one big
colony of western gulls or giant coreopsis, or both because some
gulls sit on top of them. No
sexual dimorphism among gulls. Typically
2-3 eggs; chicks are spotted like their eggs—good camouflage. Red spot on mother may be a target for chicks
to peck and get fed. About
50% survival rate in first year.
Threats: red-tail hawks, ravens, and each other. Aka “garage gulls,” because they go to the
city dump and fly back and regurgitate BBQ bones rather than squid. Also saw
pelagic cormorant and pigeon Guillemot at the cove. A beautiful female yellow warbler and song
sparrow at the Visitor Center; later, a savannah sparrow (Passerculus sandwichensis) and we watched an oyster
catcher for a long time. Gum weed
(yellow flower used by the Chumash as a salve). Bush mallow (endemic),
non-native crystalline ice plant (from Africa, which is salt tolerant), Island
buckwheat, and prickly pear. Extensive
midden site, at least two feet deep; Chumash visited this site repeatedly
because of the wonderful view, but most likely would have to have brought their
own water—a small supplement could be obtained at a nearby cave, but perhaps
only one-to-two gallons per day. At
Inspiration Point (1.5 miles roundtrip), we could see a cave on the cliffs in
the distance, where 3 peregrine falcon chicks were nesting. On the return, talked with Sarah Chaney (NPS restoration biologist) about
ironwood; she says that she has seen 2 or 3 seedlings when two different clones
come together—they do produce seeds and they are viable. She thinks this introduction would be a good
restoration strategy. Walked up to the
lighthouse, but can’t get too close due to potential hearing damage. Prompt 3:02PM departure
from dock; overcast. Sea lion nearby. Went to the south side, around the arch for
seals; saw a shortfin mako shark (or, less possibly, it was a blue shark
(Prionace glauca), given its behavior, not so likely). Sighted
a porpoise at 4:17PM as we entered harbor. Thinking about likely topics for exam and
doing a species profile on ironwood and/or jay.
Useful
resources:
58 photographs at https://plus.google.com/photos/115191388542813037913/albums/5885388777701068049/5885388827759156354?authkey=CM6qk-z-ypiYPw&pid=5885388827759156354&oid=115191388542813037913
(accessed 3 June 2013).
Bill McCawley,
“Native Plant Garden: Guide to Island Plant Adaptations” (July 2007).
Bill McCawley,
“Native Plant Garden: Guide to Island Chumash Indians Plant Usage” (undated).
“The Nature Conservancy
Interpretive Trail Between Prisoners Harbor and
Pelican Bay” (undated).
NPS, “Channel Islands” (undated).
NPS, “Channel Islands: Hiking
Eastern Santa Cruz Island” (undated).
Created: 3 June 2013; revised: 5 June 2013.