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E-M:/ Amphibian losses and forest litter

Enviro-Mich message from Gary Stock <gstock@net-link.net>

No wonder we can't fix it -- we don't even know yet what's wrong:

   ...our data suggest that declines are due to climate-driven 
   reductions in the quantity of standing leaf litter, a critical
   microhabitat for amphibians and reptiles in this assemblage..."

The abstract below puts the study in perspective.  Consider that
non-native earthworms are reducing forest litter throughout Michigan and
the Midwest.

Also, I frequently see bees using forest litter for cover on cold
evenings, late in fall, or early in spring.  Perhaps they're having the
same problem...



   'Fewer leaves' behind frog demise


   Published online before print April 20, 2007

   Proc. Natl. Acad. Sci. USA, 10.1073/pnas.0611256104

   Amphibian and reptile declines over 35 years at La Selva, Costa Rica

   Steven M. Whitfield *, Kristen E. Bell *, Thomas Philippi *,
   Mahmood Sasa, Federico Bolanos, Gerardo Chaves, Jay M. Savage,
   and Maureen A. Donnelly *

   * Department of Biological Sciences, Florida International 
   University, University Park Campus, OE 167, Miami, FL 33199; 
   Hudsonia, Ltd., P.O. Box 66, Red Hook, NY 12571; Instituto 
   Clodomiro Picado, Facultad de Microbiologia, Universidad de
   Costa Rica, San Jose, Costa Rica; Escuela de Biologia, 
   Universidad de Costa Rica, San Pedro, Costa Rica; and 
   Department of Biology, San Diego State University, San Diego,
   CA 92182

   Edited by Peter Vitousek, Stanford University, Stanford, CA,
   and approved March 6, 2007 (received for review December 31, 2006)

   Amphibians stand at the forefront of a global biodiversity crisis.
   More than one-third of amphibian species are globally threatened, 
   and over 120 species have likely suffered global extinction since
   1980.  Most alarmingly, many rapid declines and extinctions are
   occurring in pristine sites lacking obvious adverse effects of 
   human activities.  The causes of these "enigmatic" declines remain
   highly contested.

   Still, lack of long-term data on amphibian populations severely
   limits our understanding of the distribution of amphibian 
   declines, and therefore the ultimate causes of these declines.

   Here, we identify a systematic community-wide decline in 
   populations of terrestrial amphibians at La Selva Biological 
   Station, a protected old-growth lowland rainforest in lower 
   Central America. We use data collected over 35 years to show that
   population density of all species of terrestrial amphibians has 
   declined by 75% since 1970, and we show identical trends for all
   species of common reptiles. The trends we identify are neither
   consistent with recent emergence of chytridiomycosis nor the
   climate-linked epidemic hypothesis, two leading putative causes
   of enigmatic amphibian declines. Instead, our data suggest that 
   declines are due to climate-driven reductions in the quantity of
   standing leaf litter, a critical microhabitat for amphibians and 
   reptiles in this assemblage. Our results raise further concerns
   about the global persistence of amphibian populations by 
   identifying widespread declines in species and habitats that are
   not currently recognized as susceptible to such risks.

# # #

Gary Stock                                        gstock@unblinking.com
UnBlinking                                   http://www.unblinking.com/
Googlewhack                                 http://www.googlewhack.com/

               Alberto Gonzales is a liar and traitor. 
               No wonder his boss has kept him around.

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