patfoley at csus.edu
Tue Jul 15 21:30:07 EDT 2003
Rather than a fourth of July count, I think American lepsters should
consider some approach similar to the British Butterfly Monitoring
Scheme. Pollard and Yates 1993 describe the Scheme in a book called
Monitoring Butterflies for Ecology and Conservation.
The basic idea as I understand it is to run frequent (weekly) repeated
transects, attempting to account for weather variation by picking only
favorable days. The transects are walkable strip transects in locations
representing a diversity of habitats across the country. Weekly and
annual information results, which should allow easy comparison (of the
visual catch per unit effort sort).
Do any of our British or (my grandmother Bridget Murphy is rolling over
in her grave when I say it) Great British members have any comments
about their experiences with the BBMS?
patfoley at csus.edu
Michael Gochfeld wrote:
>My 4JC Ambivalence #2. Recent postings on one or both lists have both
>criticized and supported the value of the Fourth of July counts (4JC).
>When the 4JCs were started by the Xerces Society people (not NABA) back
>in the mid-1970s, the 15 mile diameter circle was adopted straight out
>of ornithology, with little regard (in my view) for the differences
>between how we find butterflies and birds (spatial scale). However, a
>number of counts made no pretense of covering such a large circle with a
>3 mile circle specified in one case (and a single backyard with a single
>species, guess which?) in another case.
>It may have made sense in terms of the area that a large number of
>people could comfortably cover in a day. And it may make sense in areas
>of the country where there is a lot of homogeneous habitat so that you
>dont need to cover the whole circle to find out whats in the whole
>In reality, most counts dont sample the entire circle, but an outsider
>wouldnt know that. Count circles may be gerrymandered to include prime
>About 15 years ago, I recommended that the 4JCs (or equivalent) focus on
----a park, a forest, a preserve, even a
>town----and get to know the fauna (and flora) in more detail. This
>suggestion was not take seriously.
>My main reasons for not liking the 4JCs
>1) We encounter butterflies at very close range (usually within a few
>meters, perhaps even a net-handle length). We encounter birds at
>distances of dozens to hundreds of meters, and we can even scope out
>ducks on a river at over a kilometer.
>2) Butterfly phenology is such that even a bivoltine species can be
>completely non-flying on the day of the count (not absent of course
>since the early life stages are hiding out). Our 4JC at Vischer Ferry,
>NY, covers the habitat of the endangered Karner Blue (L. melissa), but
>more often than not we are between broods. The editor of the first
>count noted that the 4th of July was generally not optimal and dates
>would have to be changed.
>3) There is a lot of un-tapped information. Counters may note what
>nectar sources are present, but there is no recording scheme for which
>nectar sources are actually used by butterflies on the day of the count.
>My main reasons for liking the 4JCs (apart from the fun of being in the
>field for a day), is that we try to cover the same area year after year,
>and even relatively new counts already have ten years of data.
>Patterns emerging across counts may be more valuable than temporal
>trends within counts.
>Subsequent posts will examine the limitations (and strengths) of such
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