substantially reduced average vege- 

 tation height. Typically, spike- 

 rush/beakrush flats have a large 

 proportion of open water, and most 

 if not all of this open marsh commu- 

 nity supports a thick layer of algal 

 mat. Periphyton are also abundant 

 on the submerged stems. 



Maidencane Flats 



Maidencane flats intergrade 

 with sawgrass marsh vegetation and 

 spike rush/beak rush flats producing 

 a patchwork vegetation mosaic that 

 is characteristic of natural Ever- 

 glades marshes. Floristically, 

 maidencane flat vegetation is rather 

 uniform, consisting of maidencane 

 ( Panicum hemitomon ) , sawgrass ( Clad- 

 ium jamaicensis ) , flag ( Saqittaria 

 lancifolia ) , willow ( Salix carolin - 

 iana ) , spatterdock ( Nuphar luteum ), 

 white water-lily ( Nymphaea odorata ), 

 alligator grass ( Paspalidium paludi- 

 vaqum ) , and cattail ( Typha anqusti- 

 folia ) . 



Flaq/Pickerelweed Communities 



Flag/pickerelweed ponds and 

 sloughs occupy the marsh areas with 

 the longest hydroperiod (i.e., be- 

 tween 8 and 12 months) and deep 

 soils composed of organic materials 

 (mucks and various peats). These 

 communities are generally present as 

 an open central pond or slough with 

 a marginal belt of vegetation com- 

 posed of a distinctive assemblage of 

 marsh species. Chief species are: 

 pickerelweed ( Pontederia lanceola- 

 ta) , fire flag ( Thalia qeniculata ), 

 flag ( Saqittaria lancifolia ), alli- 

 gator grass ( Paspalidium paludiva - 

 qum ) , swamp mermaid weed ( Proserpi- 

 naca palustris ) , water hyssop ( Baco - 

 pa caroliniana ) , and bladderwort 

 ( Utricularia biflora ). Most often, 

 flag/pickerelweed communities are 

 situated at the margins of tree 

 islands in the open marsh, but 

 occasionally they occur in the open 

 marsh where there is a depression in 



the bedrock resulting from fire or 

 alligator activity. These communi- 

 ties are important because they 

 represent the ecological refuge for 

 aquatic animals, both vertebrates 

 and invertebrates, during droughts 

 and seasonal dry-downs. The most 

 conspicuous of these animals is the 

 American alligator. 



6.17 DISTURBED HABITATS 



Disturbed habitats range over 

 all hydroperiods from plowed tomato 

 fields (an analog of the muhly prai- 

 ries) to canals and canal banks (an 

 analog of the marshes and ponds). 

 The vegetation of individual distur- 

 bed habitats depends not only on 

 hydroperiod but also on the nature 

 of the disturbance, its intensity, 

 and its proximity to other habitats 

 and disturbances. Actively culti- 

 vated tomato fields are obviously 

 dominated by tomatos. Abandoned 

 fields however, are open to competi- 

 tive invasion by a host of native as 

 well as exotic species. 



In general, disturbed habitats 

 are much more common in the private- 

 ly owned East Everglades area, as a 

 result of intensive agriculture and 

 drainage. Within Everglades Nation- 

 al Park these habitats are most com- 

 monly found in the Hole-in-the-Donut 

 area (see Section 2.1). 



Hilsenbeck et al. (1979) divide 

 these disturbances into three major 

 categories: (1) fire related recov- 

 ery vegetation; (2) exotic species 

 in natural secondary successions; 

 and (3) agriculturally induced suc- 

 cessions. To this can be added a 

 fourth category including dredged 

 canals and canal banks. 



Fire Related Recovery Vegetation 



Fire related recovery vege- 

 tations include three (3) types 

 of communities within the east 



118 



