MBBRP - Initial Field Assessment

[Mark Walker]

Sorry for the cross posts, but I want to make sure this is well distributed.
 
On May 5th, shortly after agreeing to help coordinate the efforts of the
scientific arm of the Miami Blue Butterfly Restoration Project (MBBRP), I
posted an announcement for an Initial Field Assessment (see attachment).
This first phase (focusing on the Upper and Lower Florida Keys) would depend
largely on the field work of David Fine, an entomologist and research
assistant from South Florida who is also a master butterfly rearer for
Butterfly World (the well known butterfly house located outside Ft.
Lauderdale).  We would also rely heavily on the expertise of a number of
respected entomological advisors.
 
Below, I provide a project status that summarizes the first 6 weeks of field
efforts.  This summary provides information as to where we are, how
effectively we have met our initial objectives, and what recommendations are
being made for the next phase.  As always, I strongly encourage all to
provide insights and suggestions.  The MBBRP is dedicated to taking a
grassroots approach to conservation where individuals from all walks of life
and levels of experience are encouraged to participate.
 
Data Collection
 
In the past six weeks Dave and a number of colleagues have clocked in over
100 hours of field work.  This includes six extended trips to the upper and
lower keys, focusing on non-intrusive examination and assessment of habitat,
identification of any unrecorded colonies, and the extent of available
hostplant.  It has also involved periodic monitoring visits to the single
remaining site where a number of colonies are known to thrive.  I had the
extreme pleasure of joining David on the most recent field trip, taking
place June 14, 15, 2002.
 
Through these efforts, we have generated a wealth of new information on the
biology of this insect and its prospects for the future.  Additional data is
essential prior to drawing any official conclusions, so it is our plan to
continue this data collection over many months and present our data formally
in a preliminary report sometime next Fall.  An earlier report may be
published sooner, if warranted.
 
Habitat Assessment and Hostplant Availability
 
While there are many documented species of hostplant, it would appear that
the butterfly's two best opportunities for survival in the Florida Keys are
through its association with the exotic Cardiospermum halicacabum, a dainty
climbing vine which used to be found more commonly in disturbed areas and on
edges of hammocks; and with Caesalpinia bonduc, a sturdy coastal strand and
hammock dweller that particularly excels in sheltered dune habitat where
there are shrubs that it can exploit for support.  
 
Cardiospermum halicacabum (a.k.a. Balloon Vine) has mysteriously disappeared
from much of its former (introduced) range, with the most probable causes
being forced eradication (through mechanical removal or herbicidal
defoliation) and/or severe weather conditions (i.e. hurricanes and unusual
cold spells).  Whatever the cause, many of the lepidopterists who frequent
the Florida Keys have documented the recent decline of this species
particularly in and around Key Largo.  When it thrives, the vine is capable
of climbing to the very top of the tallest hammock canopy, weaving its way
in and out of the host trees to maximize exposure to sunlight.  The plant
can also survive in sparser habitat, like open abandoned fields, where when
left alone it can creep its way over any vertical precipice or shrubbery.
Unfortunately, it doesn't appear to compete well with heartier plants that
are also fighting to take control of such disturbed habitats.  It also
doesn't do well in such habitats when they are subjected to regular mowing
and clearing.  It would appear that its best opportunities are along hammock
edges whenever it gets a chance to propagate there.  Most of these edges in
the keys exist along major thoroughfares which are prone to annual cutting.
Making matters worse for the insects that live in this type of habitat,
regular spraying of insecticides occurs along these highways to help control
mosquito infestation.  David and I experienced this spraying on June 15
along highway 1 near Tavernier.  It is severe, especially at the hammock
edge.
 
There appear to be relatively few remaining locations in the Florida keys
where C. halicacabum is widespread.  The few locations that have been
identified after 6 weeks of intensive searching are relatively isolated from
each other.  It would appear that until this plant is allowed to propagate
more freely, it may not currently represent a satisfactory hostplant for
reintroduction of the Miami Blue.  We will continue to monitor the success
of the plant wherever it occurs naturally.
 
Caesalpinia bonduc (a.k.a. Nickerbean) is found throughout the keys in
various coastal habitats.  More conspicuous than the vine, it can readily be
identified poking its way out of hammock edges or along the thinnest of
coastal strands.  When it is found growing in the hammock, it is usually
found as a solitary plant fighting for survival and available sunlight.  To
propagate, this plant extends stalks full of its 2" diameter seed pods which
open to deposit the very large ½" diameter seeds.  In its sand dune habitat,
the plant appears to be able to take more control and perhaps propagate
faster than when competing with hammock vegetation.  Unfortunately, life on
exposed dune habitat is equally difficult on account of weather and impact
by human recreation or development.  Many of the locations where C. bonduc
has been found involve only one or two individual plants.  We have
discovered at least four locations, however, where the foodplant is
plentiful and thriving.  We believe that these locations could provide a
suitable habitat for sustaining active colonies of the Miami Blue.  It is
not apparent why these stands of C. bonduc do not already support
populations of the Miami Blue.
 
 
Population Monitoring
 
Previously widespread throughout the keys, the Miami Blue (Cyclargus thomasi
bethunebakeri) has been mysteriously reduced to a single known location
where it thrives as a number of possibly connected populations that thrive
on sizeable stands of Caesalpinia bonduc.  The butterfly has been monitored
in this location for several years now, and appears to be doing very well.
During each visit over the 6 week MBBRP study period the butterfly has been
seen ovipositing on its hostplant.  Larvae in various stages have also been
recorded.  On June 16, 2002, the butterfly was plentiful and active, in
spite of excessive wind and torrential rain.  The extent of foodplant at
this location is great.  It is obvious when you see it why the butterfly has
done well there.
 
In spite of a careful combing, no other populations of C. thomasi
bethunebakeri have been discovered during our first 6 weeks of
investigation.  Surprisingly, only a few other locations have been
discovered that would even support sufficient hostplant for reintroduction.
These are being carefully documented.  Ongoing searches are planned
throughout the summer, when we will also begin searching mainland Florida.
 
Captive Breeding Program
 
The MBBRP has been preparing for the need of a captive breeding program for
the Miami Blue.  Many botanists, gardeners, nursery owners, and enthusiasts
have begun propagating hostplant in anticipation of this captive breeding.
As has been mentioned, there are several locations that have been identified
in the wild that would be appropriate for a reintroduction.  Until the
hostplants have been restored to necessary levels, however, a reintroduction
may prove to be futile.  Much work is required before such activities can be
recommended.
 
Research Permits
 
Part of the recommended strategy outlined in our proposal included the
request for research permits in the various protected locations that may
harbor healthy populations of the butterfly and/or one of its foodplants.
Permits were officially requested from the State of Florida some number of
weeks ago, but these permit applications requested the right to potentially
remove individuals from the protected sites.  After soliciting information
from leading entomologists, the State of Florida declined the permits on the
grounds that not enough information had been obtained to guarantee that the
removal of females would not be detrimental to the survival of the colony.
The MBBRP Science organization agrees with this decision, and regrets that
the original permit applications requested the right to remove individuals
from protected habitats.  On the other hand, such permissions may ultimately
be required.  Obtaining authorization once for all foreseeable research
activities seems prudent.
 
In actuality, the above request for permits would have gone more easily had
we followed the recommendations made by John Calhoun at the onset of the
project.  John strongly suggested that a formal letter be sent to the State
of Florida describing the organization and its agenda.  Had this been done,
we would surely have been able to secure the confidence necessary to gain
state approval.  This was a costly mistake.
 
Contact has since been made with Florida's leading entomologists in an
attempt to promote our organization and its agenda.  Permit requests are
being revisited.  Weekly trips into the field will continue, as will the
collection of data.  When appropriate, a recommendation will be presented.
 
Mark Walker
Science Coordinator
Miami Blue Butterfly Restoration Project
 
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