Spartina al terni f 1 ora , and black needle 

 rush, Juncus roemerianus , become more 

 extensive and eventually replace mangrove 

 swamps. Even in the Everglades region, 

 the saline marshes are comparable to man- 

 groves in areal extent, although they 

 tend to be some distance from open water. 

 Studies of these marshes, including as- 

 sessment of their ecological value, are 

 almost non-existent. Certainly, they have 

 considerable importance as habitat for 

 small fishes which, in turn, support many 

 of the nesting wading birds in south 

 Florida (see section 9). 



Tropical hardwood forests may occur 

 within the mangrove zone in south Florida, 

 particularly where old shorelines or areas 

 of storm sedimentation have created ridges 

 1 m or more above MSL (mean sea level) 

 (Olmstead et al. 1981). Similar forests 

 or "hammocks" occur to the rear of the 

 mangrove zone on higher ground. Typical 

 trees in both forest types include the fan 

 palm, Thri nax r a d i a t a , buttonwood, 

 Conocarpus erecta , manchineel, Hippomane 

 manci nel 1 a , and, in the past, mahogany, 

 Sw i et en i a m aha goni . Olmstead et al. 

 (1 981 ) provide a description of these 

 communities. 



Freshwater marsh plants, such as the 

 grasses, rushes and sedges that dominate 

 the freshwater Everglades, are not 

 mentioned here, although they are 

 occasionally mixed in with small mangroves 



that have become established well inland. 

 See Hofstetter (1974) for a review of 

 literature dealing with these plants. 



Finally, a group of somewhat salt- 

 tolerant herbaceous plants is found 

 within stands of mangroves. They usually 

 occur where slight increases in elevation 

 exist and where sufficient light filters 

 through the mangrove canopy. Carter et 

 al. (1973) list the following as examples 

 of members of the mangrove community: 

 leather ferns, Acrostichum aureum and A. 

 danaeifolium ; Spanish bayonet, Yucca 

 al oi fol ia ; spider lily, Hymenocal 1 i s 

 1 ati fol ia ; sea blite, Suaeda 1 ineari s ; 

 chaff flower, Al ternanthera ramosissima ; 

 samphire, Philoxerus vermicularis ; blood- 

 leaf, Iresine celosia ; pricklypear cactus, 

 p u n t i a s t r i c t a ; marsh elder, I va 

 f rutescens ; the rubber vine, Rhabdadeni a 

 bi f 1 ora ; the lianas, Ipomoea tuba and 

 Hippocratea volubilis ; and a variety of 

 bromeliads (Bromel i aceae). 



Although the lists of vascular plants 

 which occur in mangrove swamps may seem 

 extensive, the actual number of species in 

 any given location tends to be low 

 compared to totally freshwater environ- 

 ments (see Carlton 1977). Analogous to 

 temperate salt marshes, mangrove swamps 

 possess too many sources of stress, 

 particularly from tidal salt water, to 

 have a high diversity of vascular plant 

 species. 



44 



