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The Catalina Islander
Avalon, California
September 19, 2014     The Catalina Islander
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September 19, 2014

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Conservancy Times BY ALEXA JOHNSON From the tiny Catalina Island fox to one of the world's rar- est butterflies, Catalina Island is home to at least 60 plants and ani- mals found nowhere else. Known as endemic species because they are found exclusively in one geo- graphic area, their survival is essential to preserving the world's genetic diversity. Catalina's endemics are also one more fea- ture of this island that fascinates our visitors. Endemic species are fairly common on remote islands where isolation limits the addition of new individuals and can offer pro- tection from destructive mainland forces. Some endemics evolve from ancestors that arrived thousands of years ago. Over the genera- tions, individuals carrying traits that make them more successful under island conditions become more numerous. Those carrying other traits pro- duce fewer young, and some fea- tures die out over time. Selection pressures come from changes in the resources available. Those include food, water, materials, or space. Resource changes carl also affect mate selection and alter competition with and predation by other species. For example, the Catalina Island fox, known to science as Urocyon littoralis cataline, likely evolved to become a smaller ver- sion of its ancestor, the gray fox, for three reasons. Space on the island is limited, menu options are reduced compared with the mainland, and larger competitors, such as coyotes and wolves, are absent. Other endemics were once widely distributed on the conti- nent or even globally. Since colo- nizing the island in the distant past, their populations elsewhere have disappeared due to changing climate or interactions with other plants and animals. Meanwhile, the island popula- tions are protected from those pressures and continue to sur- vive. A local example is the Catalina ironwood, also known as Lyonothamnus floribundus flo- ribundus. It once had a broad distribution across North America and can now be found only on Catalina. Catalina's endeinic animals are a varied group, represented by five mammals, three birds and more than 45 species of inverte- brates (mostly insects). They're each genetically dis- tinct from their ancestors as con- firmed by DNA analysis. Some, like the fox, also have visible, physical differences that set them apart. Among the rarest of the endemic species is the Avalon hairstreak (Strymon avalona), a one-inch gray butterfly with faint yellow marking on its hind wings. It is considered to be vulnerable to extinction because it occupies such a limited range. Yet its closest relative, the gray hairstreak (Strymon melinus), is one of the most widespread but- terflies in North America. Eight plants are thought to be endemic to Catalina Island, including the Trask's yerba santa, Eriodictyon traskiae var. traskiae. Another, the Trask's monkeyflow- er, Mimulus traskiae, is presumed Come Visit ! Fun, Exciting & Unique Toys For All jesl Pet Supplies Games Puzzles Arts and Crafts Books Educational Toys Video Games Indoor~Outdoor Sports Items And so much more! The Avalon Hairstreak butterfly is one of the rarest insects in the world, left. Photo by Denise A. Knapp Trask's yerba santa, Eriodictyon traskiae subsp, traskiae, is one of Catalina's endemic plant speoies, Photo by Amy E. Catalano to be extinct because it hasn't been seen on Catalina since 1901. It's important to note that the field of taxonomy, or the classi- fication of organisms, is an ever- changing science, thanks espe- cially to DNA analysis. As further research is con- ducted, organisms that were once considered to be the same as their mainland counterpart may end up getting re-classified as endemic species, or vice versa. The protection of endemics is a high priority for conservation groups because these plants and animals are truly irreplaceable. Our efforts to remove introduced species particularly benefit our rare plants and animals. By preserving Catalina endem- ics, we are maintaining the plan- et's genetic diversity, supporting ecosystem function andultimately improving human welfare. Alexa Johnson is the Catalina Island - Conservancy's outreach and naturalist training specialist. For more information, please visit Or design your own experience on a fully equipped vessel with cabin, restroom, and satellite TV irsarlo 424.738.0080 When: Saturday & Sunday September 20th & 21 st Saturday- lO:O0am to 4:00pm Sunday- 10:00am to 3:00pm FUN Silent Auction Saturday lO:00am to 2:00pm Where: Hotel Metropole Conference Room 205 Crescent Avenue For information contact Linda at: THE CATALINA ISLANDER Friday, September 19, 201419 t