Distribution
and Abundance
Species
identity, distribution and abundance will allow us to determine
the frequency of habitats along the rivers. A long-term goal of
our project is the production of a database, allowing us to map
the distribution of habitat types along the rivers. To date we
have identified 76 species of woody plants along the riverbanks.
Of these 76 species 13 were very common and found in all of the
2000 survey areas The native tree, Sycamore
(Platanus occidentalis)
is the most frequent woody plant growing along the rivers in the
Pittsburgh Pool. The introduced Tree of Heaven (Alianthus
altissima) is the second most abundant woody plant.
Although
the data in our assessment are not yet correlated with other
contemporary or historical data, this study is significant in
that it establishes an accurate baseline to compare with future
data and historical information.‹ Some of the significant findings
that came out of our study establish the relative frequency
and abundance of native and introduced plants in the Pittsburgh
Pool:
-
Brunot Island has the highest average vegetation cover composed
of woody plants, followed by the left bank of the Ohio River.
For all other river areas measured in 2000, the percentage
of woody plants is approximately equivalent.
- The
percentage of introduced species averages 36% across all riverbanks
in the Pittsburgh Pool.‹ Herr’s Island has the highest
average abundance of introduced species (55%). The Ohio River
has the highest average incidence of introduced plants relative
to the Allegheny or Monogahela Rivers.
- Islands
in the Allegheny River display both the highest and lowest
averages of introduced plants (Herrs Island at 55% and Six
Mile Island at 20%).
>Next:
Continuity
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