S^. robustus tolerated higher salinity and greater water level fluctuation 

 than S. olneyi . In S^. robustus communities soil salinities ranged 

 from 12,000 to 22,000 ppm; water depths ranged from -6.0 and +5.0 inches; 

 and soil pH ranged from 5.6 to 6.4. Communities of S^. robustus were often 

 associated with disturbed sites, and this species is a primary invader 

 in areas of exposed soil in brackish marshes subjected to slight 

 water level fluctuation. 



Optimum seed germination of both sedges was at temperatures that 

 fluctuated on a daily cycle from 20°C to 35°C; light was a very 

 important factor influencing germination. Submergence by only one 

 inch of water inhibited germination. A sharp decline in the percent 

 germination of S^. robustus occurred between 8,000 and 10,500 ppm 

 salinity. The germination of S^. olneyi was reduced 50 percent at 

 4,000 ppm salinity. (Author's introduction and summary) 



Keywords: coastal marsh, waterfowl, fur-producing habitat, marsh 

 grasses, Scirpus , Louisiana 



V-A-9 



Rutzler, K. 1969. The mangrove community; aspects of its structure, 



faunistics and ecology. Pages 515-535 i_n A.A. Castanares, ed.. Coastal 

 lagoons, a symposium. Universidad National Autonoma de Mexico, Ciudad 

 Un i vers i dad. 



In a brief survey of the literature dealing with mangroves in the 

 sense of a littoral habitat, the points of focus and results of earlier 

 works are summarized. The various biotopes within the community are 

 classified in accordance with their dominant floristic and faunistic 

 components. It is felt that not enough consideration has been given 

 to the sedentary fauna which is reaching dominant importance on mangrove 

 roots in certain regions. The limited abundance and peculiarity of 

 the substrate raise interesting problems concerning interspecific 

 relations and dynamics of associations. 



A large number of habitats in mangrove swamps are influenced by the 

 sea. These have been greatly neglected by systematists and ecologists 

 in the past. With coordinated international and interdisciplinary 

 cooperation, it should be possible, with reasonable effort, to determine 

 the community structure; i.e. the correlation and self-determination 

 of the biocenotic units. (A.A.) 



Keywords: Mangroves, estuarine animals, ecology 



210 



