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Synecological features of a natural headland prairie on the Oregon coast

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Title Synecological features of a natural headland prairie on the Oregon coast
Names Davidson, Eric Duncan (creator)
Chilcote, William W. (advisor)
Date Issued 1966-12-09 (iso8601)
Note Graduation date: 1967
Abstract The study of the vegetation of one of the natural coastal
prairies in Oregon was undertaken for the purpose of describing
some of its synecological features. Specific objectives of the study
were to describe certain plant assemblages in the study area, present
phenological relationships on some of the assemblages, and
discuss and illustrate some examples of evidence of succession on
the study area.
The study area is a prairie located on a headland about one
mile north of the Tillamook-Lincoln county line (Sec. 3 in T6S,
R11W). This prairie is one of the many situated on the headland
bluffs and slopes along the northern Pacific coast.
During an initial period of reconnaissance, familiarization with
the plant species and communities in the study area was gained.
Several surveys along most of the Oregon coast were made to compare
the study area with other coastal prairies.
A total of 38 distinctive stands of vegetation within the prairie
were sampled in a series of five repetitive sessions from January to
October in 1966. Presence and vegetative cover of species were
recorded. In addition, soil depths in these stands were recorded.
Seven transects from the prairie through the ecotone to the
forest were established and the presence of species along them was
recorded.
With the aid of an association table five distinctive communities
were differentiated in the sampled stands. These were:
1. Equisetum maximum community, restricted to sites with
high soil moisture during the entire year.
2. Polystichum munitum-Rubus parviflorus community, usually
on soils 18 inches deep or less. Species in this community
form the major part of the ecotone vegetation.
3. Carex obnupta community, usually on soils 12 inches deep
or less. Carex is the only important species in this community.
4. Artemisia suksdorfii-Solidago canadensis community,
found on the exposed, south-facing end of the prairie on
deep soils. It is a community found commonly in prairies
farther north on the coast.
5. Solidago canadensis community, situated farther up in the
prairie than the Artemisia-Solidago community, on deep
soils. It was judged to be an earlier successional stage of
the Artemisia-Solidago community.
Two more groups were apparent in the table, but these were
judged not to be distinct communities in the field. These were:
6. Lupinus littoralis group, considered part of the internal
pattern of one or more of the large grassy communities not sampled. The peculiar grouping of Lupinus littoralis
is attributed to the large, heavy seeds of that species which
always drop directly to the ground, rather than being distributed
farther by the wind.
7. Angelica lucida-Rubus spectabilis group, judged to be an
aberrant form of the Polystichum-Rubus parviflorus community.
A discussion of successional aspects of this and other coastal
prairies on the Pacific coast was based on the results of field work
carried out during this study, a knowledge of activities on this
prairie from 1916 to the present time, and on historical accounts
and old photographs concerning the coastal vegetation. It was tentatively
concluded that the coastal prairies were maintained for long
periods in the past mostly by fires set by the coastal Indians who
lived on them. When the white settlers arrived with their cattle and
sheep, many prairies, including the study area, were maintained by
grazing pressure, and the spread of hardy introduced grasses was
encouraged.
The stands sampled in the study area were thought to have become
established during a period of no stock grazing from 1938 to
the present time.
It was suggested that the Polystichum munitum-Rubus parviflorus
community may provide sites for the growth of Picea sitchensis
within this prairie.
Genre Thesis/Dissertation
Topic Coasts -- Oregon
Identifier http://hdl.handle.net/1957/49053

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