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Treebeard's Stumper
6 September 2002

Catalina Crossings

Here is a link to my hard Catalina Crossings crossword puzzle for Dunn Middle School students to solve while they pack for our Catalina Island adventure next week. We will cross to Catalina by boat, but how did everything else get there? Current opinion is that the California Channel Islands have not been connected to the mainland since at least the Pleistocene age 1.5+ million years ago. Therefore every native plant and animal species that we see next week is a stumper. Endemic plants and animals that occur nowhere else are especially interesting. How did island plants and animals cross the ocean barrier?

Julie and I spent a week on Catalina Island last summer. We camped at the Isthmus for a few days of fabulous kayaking and snorkling and hiking. (We loved it so much that we bought our own ocean kayaks when we got home!) We then joined a volunteer weed survey with the Catalina Island Conservancy. I've collected more Catalina links on the DMS Catalina Research webpage. The first sight coming into the Isthmus harbor is Bird Rock. It's covered with a thick deposit of bird guano, like frosting on a cake. We kayaked out to Bird Rock, and the smell is "interesting," like a diaper pail. But the rock is alive with birds and interesting plants.

The plants growing from the guano on Bird Rock are a dense, low thicket of Malva Rose (Lavatera assurgentiflora), Giant Coreopsis (Coreopsis gigantea), and prickly pear cactus (Opuntia littoralis x O. oricola). It's remarkable that Malva Rose is an island endemic that only grows on Bird Rock and Indian Rock in nearby Emerald Bay. Other races of Malva Rose exist on other Channel Islands. This beautiful endemic is now in cultivation and sometimes escapes on the mainland. How did this rare shrub originally get to the Channel Islands?
There's no mystery how some plants and animals got to the islands. We saw this herd of bison in some unfortunate's campground at Little Harbor. Note the blue ice chest under the bison on the right. As I understand it, the Bison were introduced to Catalina in 1924 during the filming of a silent movie, "The Vanishing American". Fourteen animals were originally released. The bison population is now controlled at about 500, and "Buffalo Burgers" are available. The story is told at Robert Roy Jan van de Hoek's Pimu-Catalina Island Wild Nature page. However plants and animals originally got to the islands, they are still doing it with human aid. Invasive weeds and animals are an on-going management problem. But how did the original native plants and animals get to the islands without people and boats to carry them?
The most interesting Channel Island endemic might be the Pygmy Mammoth (Mammuthus exilis) fossils found on Santa Cruz Island in the Santa Barbara Channel. This photo shows the reconstructed skeleton mounted by Phil Orr at the Santa Barbara Museum of Natural History. (Photo by Wm. B. Dewey, used without permision.) There's more info in Larry D. Agenbroad's Pygmy (Dwarf) Mammoths of the Channel Islands of California (1998), available from the Mammoth Site Museum Shop. These head-high Mammoths lived on the Channel Islands just 12,000 years ago. The world is poorer without them. Pygmy Mammoths are a great oxymoron, but they are also part of the stumper about how plants and animals colonize islands.


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