Pacific Grove Prunes Monarch Cluster Trees

[Paul Cherubini]

PACIFIC GROVE TREE TRIMMING MIGHT HAVE CAUSED LOW
MONARCH TURNOUT
By Kera Abraham Nov. 19, 2009 http://tinyurl.com/ydo6f2f

In a city nicknamed Butterfly Town, USA ­ where an annual
Butterfly Parade marks the beginning of the monarch overwintering
season, and tourists flock to visit the famous Butterfly House ­ the
absence of thousands of orange-and-black-winged annual visitors
is something of an identity crisis.

"If Butterfly Town loses its monarchs ­ not good," says Pat Herrgott,
a long-time volunteer docent at Pacific Grove's Monarch Grove Sanctuary.

The sanctuary is low on butterflies this year, and some monarch
enthusiasts suspect that the city's heavy-handed trimming of eucalyptus
branches is to blame.

"It was obvious to me this amount of pruning will substantially degrade
the suitability of the sanctuary as a cluster site, "entomologist Paul
Cherubini wrote on a monarch listserv in late October. "The butterfly
population is likely to be substantially lower and less stable this year
and for years to come."

P.G. Public Works Director Celia Perez Martinez says the trimming
was done for public safety in late September, before the Oct. 1 start
of monarch overwintering season. (In 2004 an 85-year-old woman
was killed by a falling branch while visiting the sanctuary; the city
settled with her family for $1 million.)

"Eucalyptus trees are very vulnerable to limb breakage," she says.
"[But] we would not have trimmed any branches that had butterflies
on them."

City arborist Rick Katen directed a tree service on which branches
to cut, Perez Martinez says, but the city didn't document the work.
"In the future we1ll do that, but we've never done it in the past,"
she says.

This year's low butterfly numbers could be caused by any number
of things, she says, including October's storms:  "They could have
gone to Santa Cruz for all we know."

Dr. Francis Villablanca of Cal Poly is tasked with reviewing the
monarch count data. "At the current time we do not know if the
P.G. Sanctuary population count is low because of something
peculiar to this site (e.g.: tree trimming), or if the populations
are low range-wide and across all sites," he wrote in an e-mail
to Perez Martinez.

Villablanca expects to have some findings within the next few
weeks.  "I would call for calm minds to prevail until we have
some data," he wrote. "The story will make itself evident."

But Bob Pacelli, who has been filming P.G.'s monarchs for
two decades, has a strong hunch that the trimming messed
up the particular microclimate ­ humidity, temperature, precipitation
and wind shelter ­ that makes the P.G. sanctuary a critical
overwintering site.

Last year at this time, he says, the monarch clusters were dense.
This year he could barely spot any butterflies. "Every single place
that the monarchs could hang onto is gone," he says morosely.
"I hope I'm totally wrong, but in my heart I know it's not true.
No more butterflies. Oof."
=========================================
ANNUAL BUTTERFLY COUNT SHOWS DRAMATIC DECLINE IN PACIFIC
GROVE'S MONARCH GROVE SANCTUARY
By Kera Abraham November 30, 2009 http://tinyurl.com/yhjf5t6

An annual count of monarch butterflies shows dramatically low
turnout at Pacific Grove's Monarch Grove Sanctuary this year,
confirming the suspicions of monarch enthusiasts who blame
heavy tree pruning done by the city in late September.

According to El Dorado-based entomologist Paul Cherubini, this
year's monarch population estimates, as compared to
Thanksgiving 2008, are:

Up 34 percent in Santa Cruz's Lighthouse Field State Park;
Down 38 percent at Moran Lake, Capitola;
Down 34 percent at a private property near Big Sur:
Down 96 percent at P.G.'s Monarch Grove Sanctuary.

Cherubini blames the disproportionate decline in the P.G. sanctuary
on the trimming. He predicts that the butterflies will abandon the
sanctuary between mid-December and mid-January, and may not
return to it as a regular overwintering spot.

"The city itself inadvertently ruined its own butterfly habitat via
the tree pruning," Cherubini writes by email. "The city could have
used tree rope or wire cables to secure the dangerous branches
instead of cutting them."

City Public Works Director Celia Perez Martinez has said that the
low butterfly turnout this year could be due to any number of
factors besides the trimming. She is awaiting a more comprehensive
assessment by Cal Poly professor Francis Villablanca.

The relative absence of butterflies in P.G. comes in the context of
what appears to be a long-term decline in the western monarch
population, which may be caused by a variety of factors, including
summer droughts, invasive parasites, habitat degradation and the
disappearance of the Central Valley's native milkweed, the only
plant on which monarchs will lay their eggs.

 
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