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 Since
2002, Walter E. Meshaka, Jr., Ph.D., Curator of Zoology/ Botany
at the State Museum in Harrisburg, has been systematically
marking and recapturing snakes that he finds under cover in
three fields at Powdermill. How abundant each species is and
where each is found is not known for Powdermill and poorly
known for Pennsylvania in general. Through long-term study
at Powdermill, he hopes to answer the question: what is the
composition of the snake community? That is to say, how many
of each species of snakes occurs at Powdermill? By knowing
the answer to that question and knowing the life histories
of each species, he can then answer the next logical question:
why are snake communities at Powdermill structured as they
are? That is to say, what is it about the habitat that results
in the particular combination of species and their abundances?
To date,
ten species of snakes have been reported from Powdermill.
Far and away, of the six species he has found at Powdermill,
the eastern garter snake is the dominant snake of the grassland
habitat (68.5%). Although much less common, ringneck snakes
are nonetheless seen throughout much of the active season
(14.7%), whereas the redbelly snake (9.8%) and smooth green
snake (4.4%) are seen most during June when females are full
of young. Rat snakes are uncommon (1.6%), perhaps because
of the thickness of the forest, and water snakes, not surprisingly,
make a rare appearance (1.1%) as they travel between aquatic
habitats. |
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 Begun
at Powdermill in 1958 by Dr. Graham Netting, then-Director of
Carnegie Museum of Natural History, individual mark-and-recapture
research of two long-lived turtle species, the Eastern box turtle
(Terrapene carolina) and the wood turtle (Clemmys
insculpta), continues today under the direction of Powdermill
Research Associate Dr. Walter Meshaka of the State Museum of
Pennsylvania. Long-term study of both turtles at the same place—in
this case near the northern and southern limits of their ranges,
respectively—is exceedingly rare and provides the unique
opportunity to answer questions regarding their growth, longevity,
nesting, and seasonal movements. Such valuable data, in turn,
provide the information necessary to manage populations of these
long-lived, somewhat mysterious denizens of Pennsylvania forests.
As part of his research at Powdermill, Dr. Meshaka has captured
a snapping turtle which he extracts from a specially designed
hoop net. In this image, he removes the 18-pound reptile which
he will mark, record, and then release back into its home in
Crisp Pond.
 With
approximately 450 records of total sightings during this long-term
mark-recapture study, wood turtles outnumber box turtles two
to one in both numbers marked and total numbers of sightings,
but that overall trend has begun to reverse strongly in the
past 10-15 years. Click
here to see a preliminary summary of Powdermill’s long-term
turtle data (1.0 Mb Acrobat PDF; if you do not
have Adobe Acrobat Reader, click
here for the free download).Comprehensive statistical
analysis of the growth, abundance, and movement (home range)
data is currently underway as part of a comparative study
of the two species planned for publication in 2006.
The young
lady with a turtle pictured here is Tricia Miller, our Netting
Environmental Fund Intern in 2004, who worked directly on
the turtle project under the direction of Dr. Meshaka and
Powdermill’s Field Ornithology Projects Coordinator,
Robert Mulvihill, who continued annual data collection for
the study for a few years before and following Dr. Netting’s
death in 1996 at the age of 92.
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In 2006,
Powdermill received a grant to establish a GIS (Geographic
Information Systems) lab. A GIS is basically a computerized
mapping system that allows for the mapping of spatial data
with detailed information in the form of tabular data. There
are many familiar examples of GIS including MapQuest and Google
Earth.
The goals
of the GIS lab are many and include the following:
- Create
detailed vegetation maps at a 20m scale
- Map
surface water and wetlands
- Map
ancillary features such as trapping locations, trails, roads,
buildings, etc.
- Create
maps for staff and research associates
- Provide
GIS support for researchers
- Create
a central repository for all data collected on PN
The establishment
of a GIS lab at Powdermill will facilitate the creation of
an archive of the present ecology of the Reserve and permit
the tracking of changes to the Reserve caused by succession,
establishment of invasive species, and over-browsing by deer.
And, importantly, it enables informed land management
decisions through increased scientific knowledge.
As of
January 2007 over 800 vegetation points have been mapped in
two of Powdermill’s fields. This includes precise geo-referencing
of nearly 13,000 trees! During the winter we expect to complete
the mapping of streams and wetlands and ancillary features.
We have already produced several maps for staff on the Reserve
and are currently collaborating with Dr. Todd Katzner at the
National Aviary on a project tracking Golden Eagles in eastern
North America. (See http://www.aviary.org/csrv/eaglePA.php
and click on Track
an eagle on its migration route). |
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Betty
S. Ferster, Ph.D., Assistant Professor of Biology at
Shippensburg University has been studying bee diversity
at Powdermill Nature Reserve since 2001.
 In ecological
studies it is often important to be able to measure ecosystem
function and health, but researchers struggle to find ways
to measure the health of an ecosystem. Using bee diversity
solves many of the concerns raised about studies using
single species, because there are diverse species that
vary on a basic bee life history strategy. All bees rear
young on pollen and nectar from flowering plants, but species
differ in range of suitable host plants and in nesting
habits. Current methods of maintaining open grassland areas
for conservation (fall mowing and prescribed burning) may
not support healthy native species diversity, but examining
ecosystem function as a consequence of stewardship practices
is not commonly done.
Dr. Ferster
has been collecting bees at Powdermill in the Crisp Pond
area and at the Freidline
fields since 2001 in order to learn about the bee diversity
found in open areas that are maintained for bird diversity.
She is working to compare these data with bee diversity
and plant diversity data collected at other Pennsylvania
sites that differ in the types of disturbances that are
used to maintain open areas for a variety of purposes.
She hopes to be able to show that bee diversity can be
used to measure ecosystem health and function, and to
help us understand what methods work best for maintaining
biodiversity
in old-field grassland habitats of the Northeastern U.S.. |
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Cryptobia
innominata
(photo: Acta Protozoologica)
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Powdermill
Nature Reserve: Type Locality for a Flagellate Protozoan
Powdermill
Nature Reserve (PNR) is now the type locality for a flagellate
protozoan that is a parasite in a land snail. The new
species of flagellate, Cryptobia innominata, is
microscopic with two whip-like flagellae and occurs in
the northern threetooth land snail, Triodopsis tridentata.
PNR is the type locality for the new flagellate because
the “host” snail was collected from PNR by Malacology
Curator Tim Pearce during BioForay in
June 2002.
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Triodopsis
tridentata
(illustration: Emily Ullo)
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The new
flagellate was described in the journal Acta Protozoologica (2004,
vol. 43, pp. 123-132) by protozoologist Eugene N. Kozloff
of Friday Harbor Labs in Washington State. Dr. Kozloff was
skeptical about J. Leidy’s 1846 description of a related
flagellate as occurring in three different species of snails,
because the parasitic flagellate is passed among host individuals
when they mate. Since snails mate with their own species,
different species of snails could have different species
of flagellates. When he examined the flagellates in the PNR
snail, his suspicion was confirmed, and he named the new
species of flagellate from the PNR snail.
A type
locality is where a particular type specimen was found.
The type specimens (individuals he examined when he wrote
the description of the new species) of the flagellate
are deposited in the collection at the Smithsonian. Type
localities are important because if someone needs to
examine additional specimens, the best place to look
is the type locality. For more about this specimen, visit
the online article in Acta Protozooligica: http://www.nencki.gov.pl/pdf/ap/ap725.pdf.
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coming
soon!
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