. Bulletins of American paleontology. Climatic and Anthropogenic Impacts: Willard et al. 53 SITE 7 Radiometric Dales ^ '*-'" ^^ - 1900 AD 280 - 400 AD # ^.- ^-^-^ „6^. 0 10 20 30 40 PERCENT ABUNDANCE 10 20 30 40 50 60 70 80 90 cr IV c IV d2 IV C Dwarf Mangroves IV d2 IV a Brackish and II Freshwater IVIarshes IV a IV d1 IV d2 SQUARED CHORD DISTANCE Wet Prairies/ Sparse Sawgrass fitarshes ^^ Myrica I— 1 Asteraceae Text-figure 8.—Percent abundance of pollen of major plant groups at site 7. Taylor Creek. SCD values show lowest squared chord distance values for modern analogs; SCD < are
. Bulletins of American paleontology. Climatic and Anthropogenic Impacts: Willard et al. 53 SITE 7 Radiometric Dales ^ '*-'" ^^ - 1900 AD 280 - 400 AD # ^.- ^-^-^ „6^. 0 10 20 30 40 PERCENT ABUNDANCE 10 20 30 40 50 60 70 80 90 cr IV c IV d2 IV C Dwarf Mangroves IV d2 IV a Brackish and II Freshwater IVIarshes IV a IV d1 IV d2 SQUARED CHORD DISTANCE Wet Prairies/ Sparse Sawgrass fitarshes ^^ Myrica I— 1 Asteraceae Text-figure 8.—Percent abundance of pollen of major plant groups at site 7. Taylor Creek. SCD values show lowest squared chord distance values for modern analogs; SCD < are considered to be close analogs for fossil assemblages. Cluster designations refer to clusters designated in Te.\t-fisure 3 and Table 3. The advent and evolution of water-control practices in soutii Florida inas resulted in unprecedented changes in vegetational distribution. The greatest and most re- gional impacts were seen by 1930. when shallower water and shorter hydroperiods are documented in most Everglades cores. These drier conditions oc- curred at a time of higher than average precipitation, indicating that vegetational and hydrologic changes re- sulted from hydrologic changes to the system. The combined effects of reduced sheet flow due to water diversion through canals and disrupted seasonal water supply due to construction of the Hoover Dike were sufficient to shift the Ridge and Slough ecosystem from a deep-water slough to a sawgrass marsh with abundant weedy annuals. At both sites in Taylor Slough, weedy species also increased in abundance, although the impact on water depths is less clear In contrast, alterations associated with construction of the Central & South Florida (C & SF) Project in the 195ns and 1960s appear to have had more localized impacts on marsh vegetation. Some sites underwent striking changes after 1960, such as expansion of cattail marsh- es at nutrient-enriched sites, whereas other sites saw minimal change. These observations are
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