|
. ~.
<br />A simpler relationship was observed for the
<br />shrub-scrub type, Table 2 shows a steady decline
<br />from 1938 to 1982. From 1938 when there was
<br />25,037 acres of this type, there was a decline to
<br />9,837 acres by 1982.
<br />The herbaceous cover type was consistently
<br />the most abundant riparian type within the flood-
<br />plain and substantial losses of this type have
<br />also been documented. Data presented in Table 2
<br />provide evidence that in 1938, 52 percent of the
<br />floodplain was classified as this type and that
<br />early in the study period (by 1956) the areal
<br />extent of this type had been reduced to dust 25
<br />percent of the floodplain.
<br />"Loss to development" accounted for most of
<br />this reduction. During the early period, 42 per-
<br />cent (40,333 acres) of sll herbaceous cover was
<br />"loss to development," predominantly cropland.
<br />Throughout the study period, most agricultural
<br />development has bean on land formerly classified
<br />`as this type.
<br />Many wetlands that may have been included
<br />within the herbaceous and other cover types may
<br />have been-lost or mechanically altered during the
<br />initial phases of agricultural development within
<br />the floodplain. These would probably have included
<br />seasonal and temporary wetlands that form in topo-
<br />graphic depressions, as well as permanent wetlands
<br />in oxbows, channels that had been naturally
<br />arrested, and low areas of subterranean irriga-
<br />tion. Those-that were not impacted during initial
<br />development may well have been altered dut to
<br />agricultural grading of upper terraces, which by
<br />1982 had bean extenaiva enough to oDlitarate many
<br />of the original terrace contours from en aerial
<br />view, Wotlsnda are an Important component of the
<br />riparian community, but were not included in the
<br />inventory or the subsequent analyses, due to the
<br />poor resolving power of the black and white prints
<br />that were aveitable.
<br />Information provided in this study provides
<br />some 9nsights into how dynamic the surface compo-
<br />sition of the riparian system has been in terms of
<br />agricultural development and natural events.
<br />REFERENCES CITED
<br />Batchelor, R., M. Erwin, R. Martinka, D. McIntosh,
<br />R. Pfister, E. Schneegas, J. Taylor, K.
<br />Welter. 1982. A taxonomic classification
<br />system for Montane riparian vegetation types.,
<br />USDA, Coop. Extension Service, Rural Areas
<br />Development Committee. MSU, Bozeman. 13 pp.
<br />Cowsrdtn, L.M., V. Carter, F.L. Go1et, E.T. LaRoe.
<br />1979. ClasslfiCatlon of wetlands and
<br />deepwater habltata of the Unltmd Ststes.
<br />U.S, Fish end Wildlife Service, Biological
<br />Services Program; FWS/OBS-79/13. December.
<br />103 pp.
<br />Haugen, G. 1980. Position paper on management
<br />and protection of western riparian stream
<br />ecosystems. American Fisheries Society -
<br />Western Div., Tualatin: Oregon. 24 pp.
<br />Johnson W.C., R.L. Burgess, W.R. Keamnerer.
<br />196. Forest overstory vegetation and
<br />environment on the Missouri River floodplain
<br />in North Dakota. Ecological-Monograph;
<br />46:59-84.
<br />MfDNRC. 1979. River mile index of the Missouri
<br />River. Water Resources Div., Montana Dept.
<br />Natural Resources 6 Conservation. Helena.
<br />January. 142 pp.
<br />Ohmart, R.D., W.O. Deason, and C. Burke. 1977.
<br />riparian case history: The Colorado River.
<br />USDA Forest Serv., Gen. Tech. Rpt. RM-43:
<br />35-47.
<br />Taylor, D.W. 1982. Eastern Sierra riparian
<br />vegetation: ecological effects of stream
<br />diversions. Contribution No, 6, Mono Basin
<br />Research Group. ,(Rep, to Inyo National
<br />Forest.) 56 pp.
<br />USFWS. 1946. A report on the fish and wildlife
<br />problems in relation to the water development
<br />plan for the Canyon Ferry Reservoir:
<br />Missouri River, Montana. U.S. Fish and
<br />Wildlife Service. (on file with USFWS in
<br />Billings, Mont.).
<br />1948. Fort Randall Reservoir: A
<br />preliminary evaluation of the effect of the
<br />Fort Randall Dam and Reservoir on fish and
<br />wildlife resources. U.S. Fish and Wildlife
<br />Service. February. (on file with USFW5 1n
<br />Pierre, S.D.).
<br />_ 1960. Lewis and Clark Lake: A
<br />preliminary evaluation report on fish and
<br />wildlife resources, Gavtns Point Reservoir,
<br />South Dakota end Nebraska. U.S. Fish and
<br />Wildlife Service. August. (on file with
<br />USFWS in Pierre, S.D.).
<br />1952. A report on the development oP
<br />fish and wildlife resources for Garrison
<br />Reservoir, Missouri River, North Dakota.
<br />U.S. Fish and Wildlife Service. September.
<br />(on file with USFWS 1n Bismarck, N.D.).
<br />USCOE. 1977. Missouri River, South Dakota,
<br />Nebraska, North Dakota, Montana: review
<br />report for water resources development.
<br />Appendix 1. Tech. Rpt. Vol 2 of 3, pp. 85-6
<br />and 8-55. Missouri River Div., Dept. of
<br />Army, Washington, D.C.
<br />_. circa 1981a. Lake Sharpe: Final
<br />feastbility report/Final EIS, Lake Oahe/Lake
<br />Sharpe, South Dakota, fish and wildlife
<br />mitigation. Omaha Oistrlct, Corps of
<br />Engineers, Dept. of Army, Omaha.
<br />circa 1981b. Lake Oahe: Final
<br />feasibility report/Final EIS, Lake Oahe/Lake
<br />Sharpe, South Dakota, fish and wildlife
<br />mitigation. Omaha District, Corps of
<br />Engineers, Dept, of Army, Omaha.
<br />circa 1981c. Flooded areas and
<br />profile, Vol. 4. Omaha District. Corps of
<br />Engineers, Oept. of Army, Omaha. March.
<br />.:. f .ti.rsr-.~r.
<br />
|