"dire straits faced by most of our butterfly fauna"

Roger Kuhlman rkuhlman at hotmail.com
Mon Apr 30 08:50:40 EDT 2007

I too found this article excellent and glad it was posted. We here in southeast Michigan have not been having droughts but we have a huge problem with habitat destruction and isolated patches of habitat. I wish we had detailed, rigourous observations going back 35 years here. I am sure they would also show a serious decline in butterfly populations. 
What I do know is that we have lost somewhere between 5 and 10 butterfly species in southeast Michigan during this time including Karner Blue, Frosted Elfin, and Regal Fritillary. A number of other species that have been here for a long time are hanging on by a thread.
Roger Kuhlman
Ann Arbor, Michigan
4/30/2007> Excellent article, thanks for posting it. Great insights on the Central> Valley and surrounding area by Dr. Shapiro, who I have personally observed> keeping superb records at his sites.> Best wishes,> Doug> > > ----- Original Message ----- > From: "Paul Cherubini" <monarch at saber.net>> To: "Leps-L" <LEPS-L at lists.yale.edu>> Sent: Sunday, April 29, 2007 3:06 AM> Subject: "dire straits faced by most of our butterfly fauna"> > > Dr. Arthur M. Shapiro, professor of Evolution and Ecology at UC Davis,> is in the news this Spring again with yet another doomsday newspaper> article in regards to butterfly abundance and diversity in the southern> Sacramento Valley of California:> http://www.dailydemocrat.com/areanews/ci_5780407> This time Shapiro fully authored the article so there can be no doubt> about what he said or meant.> > Professor Shapiro's article is abundantly laced with worrisome,> emotion stirring terminology and phases like: "serious trouble", "most> alarming trend", "last year was catastrophic","dire straits", "grim> outcome", "obviously in trouble", "most likely villain",> "is the crisis over? Hardly.", "highway to Hell." See below.> > Drought not all bad for butterflies> By Dr. ARTHUR SHAPIRO> Article Created: 04/29/2007 09:46:18 AM PDT> > Butterflies in our part of California have had some tough times lately.> Most people say there aren't as many butterflies now as there were> when they were kids. Because I've been monitoring butterflies on a> biweekly basis at up to 10 sites in this part of California since 1972,> I was in a position to say whether or not that was true. And by and> large, it wasn't. I used to argue that butterflies are just more> conspicuous to kids than to adults, and it was all just a matter of> perception. Until 1999, that is.> > In 1999, more than a dozen species in our area showed a sharp> downturn. I began to sit up and take notice. Was something actually> going on? In a word, yes.The North American Butterfly Association> sponsors a Fourth of July butterfly count modeled on the Audubon> Christmas Bird Count. This is a free-form, rather unconstrained> activity, and it's questionable what, if anything, the data it generates> can tell us about trends in butterfly numbers or diversity. But since> the '70s I had been doing my own count right here in Davis, and> it was completely standardized in methodology - so it was potentially> informative. The question was, what if anything can one day's> sampling a year tell us?> > Several years ago a group of us set out to explore that question,> using a variety of statistical tools. One of them was a diversity> measure called "Fisher's alpha," brought to our attention by> Professor Michael Rosenzweig of the University of Arizona.> There were no grossly obvious trends in the data set, but when> it was analyzed using Fisher's alpha, a grim outcome resulted.> The analysis told us we were already experiencing a decline> ("subclinical," in epidemiological parlance), and it was likely> to accelerate to the point where it would become obvious.> Well, in 1999 it did. But in retrospect, we can see signs of it> already in 1998.> > Most of the species that went downhill in 1999 recovered to> some degree in subsequent years, but not completely, and> some began drifting downward again. The most alarming> trend was the loss of common, weedy species - the antithesis> of the stereotypical endangered super-specialist. The Large> Marble butterfly disappeared from one after another of my> long-term sites, despite the fact that it breeds on weedy> mustards and wild radish, which are not exactly in short> supply. The Common Sootywing breeds on amaranth> pigweeds and garden cockscomb and was in every weedy> yard and vacant lot in Yolo County (it doesn't occur in> wildlands!).> > It disappeared from all my sites but one. Some of the other> species obviously in trouble, while not weedy, had been> superabundant not so long ago and hardly seemed good> candidates for extinction. The Willow Hairstreak used to> swarm by literal millions along Putah Creek on the Valley> floor. Now it was gone - completely gone.> > Meanwhile, several billion migrating Painted Ladies originating> in the waterlogged deserts of Southern California filled our> skies in the spring of 2005, masking from the general public> the dire straits faced by most of our butterfly fauna.> > When we did statistical analyses comparing butterfly trends to> climatological data, we got no consistent patterns. Some> climatic variables were better correlated with the trends than> others, but their relative importance was inconsistent from> place to place as well as from species to species. At any rate,> correlation does not prove causation. "Green" folks were> quick to suggest agrochemicals or genetically-engineered> crops were behind the declines, but they did not "fit" the> picture well.> > For example, despite all the hoopla about BT corn pollen> being toxic to Monarch butterfly larvae, not only had there> never been any convincing evidence of impacts in the field,> but there wasn't any BT corn here anyway and besides,> the pollination season didn't mesh with the life cycles of> most of the declining species.> > The most likely villain seemed to be the changing pattern of> land use in our region, and especially the loss of connectivity> among habitat patches. That's what we're working on now.> > Meanwhile, the weather in late winter and spring 2006 was just> about the worst possible for butterflies in the Central Valley - cool,> cloudy and very wet. Areas of the Yolo Bypass and the> American River floodplain remained under water into June! Last> year was catastrophic for many butterflies, and for the species> already in decline it appeared to be the coup de grace. It looked> like a substantial number of species had been lost, perhaps even> regionally. In 2006 there weren't even any significant numbers> of Painted Ladies; it was a very dry year in the desert.> > Well, it's been a dry year here in water year 2006-07. So dry, in> fact, that the Yolo Bypass never filled up with water. Even the> vernal pools never filled up with water. Drought may be bad for> Painted Ladies in the desert. But the winter of 2006-07 brought> a miraculous rebirth to our moribund butterfly fauna! Species> that seemingly had disappeared were back, sometimes in quite> respectable numbers. Some things, including the Large Marble,> were seen at some localities for the first time in five or six years.> The Purplish Copper, which had been on the skids, had a very> good summer in the Yolo Bypass in 2006. It normally would> have been largely or completely drowned out over winter.> > It wasn't, and the first adults came out extremely early. And then> on April 10 I counted 39 of them in my study site, which is more> than I had seen at all my sites put together in most of the last> several years! Similarly, the Pygmy Blue, which is normally> eradicated by flooding in the Suisun Marsh every winter, flew> all winter and resumed breeding in March for the second time> in 35 years!> > So is the crisis over? Hardly. My "take" on this is as follows:> butterfly populations normally suffer heavy mortality over winter,> probably due to a mixture of drowning, freezing, and bacterial> and fungal diseases favored by mild and wet conditions near> the ground. This droughty winter providentially reduced this> mortality to the point where populations that had declined to> the point of invisibility became visible again. But the underlying> mechanisms of decline, whatever they are, are still in place.> What is happening right now might just be a detour on the> highway to Hell. But the message for butterfly lovers is "Enjoy> it while it's here!"> > Paul Cherubini> El Dorado, Calif.> > > ------------------------------------------------------------ > > For subscription and related information about LEPS-L visit:> > http://www.peabody.yale.edu/other/lepsl> > > > > ------------------------------------------------------------ > > For subscription and related information about LEPS-L visit:> > http://www.peabody.yale.edu/other/lepsl > > 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.yale.edu/mailman/private/leps-l/attachments/20070430/0119c928/attachment.html 

More information about the Leps-l mailing list