Watershed Conservation Plan - Destination Erie

Another aquatic-dependent predator that occurs in the northwestern portion of the state is the black
bear. Data in Ternent (2005) indicates that the black bear population in Pennsylvania has been steadily
increasing since 1980 (three to four times more bears in 2000–2004 than in 1980–1982). A total of 21
bears were harvested in the 1B WMU in 2004, although it is unlikely that any were taken in the study area
(Ternent 2005). Forested wildlands including wetlands are important for black bears, which utilize
"brushy swamps" that provide plant forage and wallows (Fergus 2004).
Although white-tailed deer are primarily an upland mammal, they readily utilize densely vegetated
wetland areas for food and cover. White-tailed deer are abundant in the region, as indicated by harvest
statistics of the PGC (Rosenberry and Wallingford 2005). Approximately 17,000 deer were taken by
hunters in the 1B WMU during the 2004–2005 season, despite an apparent decline in population during
2003–2004 (as indicated by "catch-per-unit-effort" deer population index). There were fewer road-killed
deer in Erie and Crawford Counties in 2004 than in 1978 (Rosenberry and Wallingford 2005). Continued
harvesting of white-tailed deer is important for maintaining plant community diversity, since this mammal
has shown a well-documented negative impact on forest regeneration (Bowles and Campbell 1993) and
survivorship of rare and endangered plant species in the study area (Campbell 1993; Campbell et al.
1994).
6.1.6 Invertebrates—Mussels
Twelve of the 17 invertebrates listed in the PNHP database for the Pennsylvania Lake Erie
watershed (see Table 6.1) are freshwater mussels (unionids). Most of these species were presumably
known to occur in Lake Erie waters of Presque Isle. The only study area stream known to support
unionids is Conneaut Creek. Weber and Campbell (2005) recently investigated records of freshwater
mussels from Conneaut Creek found in the Carnegie Museum (historical collections of Ortmann: 1909-
1919), Ohio State University (1969 records), and the Cleveland Museum of Natural History (collections
made between 1989 and 2003). Weber and Campbell also conducted a field survey of Conneaut Creek
unionids at over a dozen different locations in the Conneaut Creek watershed during autumn 2004.
The Weber and Campbell (2005) study found evidence that Conneaut Creek has supported
populations of at least 17 different species of freshwater mussels since the early 1900s, with at least 13
species likely represented in the modern community. The collective list (including species known both
from museum collections and the recent survey) includes nine "special concern" unionid species listed in
the larger state PNHP database. Five of the special concern mussels for Conneaut Creek, including four
species found in recent surveys, are taxa that were not identified in the PNHP database for the
Pennsylvania Lake Erie watershed (see Table 6.1). It should be noted that the autumn 2004 survey
conducted by Weber and Campbell consisted primarily of collecting empty shells deposited on exposed
gravel bars following major storm events. It is expected that more-intensive sampling of live mussel
populations would likely produce specimens of more than 13 species, perhaps including individuals of the
other four species known to inhabit the stream historically based on museum collections. A
comprehensive assessment of the freshwater mussel community of Conneaut Creek should be carried out
to determine the status and distribution of likely "special concern" species present.
6.1.7 Invasive Aquatic Animals
Summary reviews of the sources and problems caused by aquatic invasive species in the Lake Erie
basin may be found in the Lake Erie LaMP (USEPA 2006) and the New York Sea Grant Fact Sheet
(O'Neill 2004). This report will not address invasive species issues relative to Pennsylvania's open waters
of Lake Erie or Presque Isle but, rather, will briefly review what is known about the major invasive
aquatic animals of the nearshore/coastal zone and streams of the study area.
One of the biggest problem invasive species in the nearshore/coastal area of the watershed is the
zebra mussel (Dreissena polymorpha), which has dramatically altered the littoral ecosystem of Lake Erie
since its introduction in the 1980s. Zebra mussels have caused a profound shift in how energy is
transferred through the Lake Erie food web—essentially redirecting energy captured by phytoplankton to
the bottom—at the expense of the "traditional" pelagic (open water) system mediated by zooplankton
(reviews in Campbell and Kenyon 1994; Perry et al. 2000; Stewart et al. 1998). Removal of
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