FRIENDS OF EDGEWOOD NATURAL PRESERVE
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FRIENDS OF EDGEWOOD NATURAL PRESERVE
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BAY CHECKERSPOT UPDATE By Stuart Weiss, Ph.D. There are Bay checkerspots at Edgewood this year. But not very many. Our larval surveys in February turned up a single postdiapause larva. Doing a back-of-the-envelope calculation, there are likely less than 100 larvae across the habitat. We will look for adult butterflies fairly intensively this spring. Many factors contributed to this admittedly disappointing result. Obviously the 2007 drought may be to blame. Relatively rapid drying of Plantago and low densities of owl's clover cause high mortality of prediapause larvae. Other factors to consider are pupal mortality, parasitoid loads, and perhaps most importantly for population establishment, the tendency of adult butterflies to wander off the 35 acres of Edgewood habitat because they do not recognize edges. Butterflies on thousands of acres of continuous habitat on Coyote Ridge rarely encounter the edges of the habitat. Butterfly reintroductions can fail; it’s the nature of the game. Successes may require many years, even decades to "take." A deeper consideration of Edgewood’s results will be presented after the Coyote Ridge data are in. We will carefully consider our options, and likely will ask for a permit amendment to repeat the reintroduction several times over the next 5 years. |
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