Table 22. Wildlife species richness 

 (number of species) in the chenier plain 

 marshes (Gosselink et al . 1979). 



in salt marshes, for example, whereas 13 

 amphibian and 24 reptilian species inhabit 

 the fresh marsh. Bird species richness 

 does not vary much over these zones, per- 

 haps because birds are mobile and can 

 easily move from one area to another. The 

 richness of swamp forest habitats is 

 included in the table for comparison. It 

 is higher for all groups, probably re- 

 flecting the higher structural heterogene- 

 i ty of that habitat. 



Although preferred habitat conditions 

 vary with individual species, Weller 

 (1978) suggested that the following 

 characteristics can lead to increased 

 wetland use: (1) Diversity of plant 

 communities. Wildlife are usually more 

 densely distributed where several dif- 

 ferent plant zones occur than in homoge- 

 neous stands. The structure of the habi- 

 tat is apparently more important for nest- 

 ing than the particular taxonomic makeup. 

 Bird species that prefer tall, robust 

 vegetation, for example, seen to be equal- 

 ly satisfied with cattails, bulrushes, or 

 small willows. This is not true for feed- 

 ing since decided preferences are found, 

 especially for annual plants such as mil- 

 lets with abundant seed and for tuberous 

 species. (2) High edge zone:marsh ratio. 

 Apparently both the edges between differ- 

 ent vegetation zones and between vegeta- 

 tion and water are important. For example, 

 the ideal in midwestern pothole marshes 

 appears to be a "henimarsh" that has a 1:1 

 or 1:2 ratio of marsh to water with good 

 interspersion between the two (Weller 

 1978). For' waterfowl, the size and depth 

 of shallow marsh ponds is particularly 

 important. 



In the delta marshes, waterfowl 

 studies have emphasized their distribution 

 with respect to the broad vegetation zones 

 of the coast. Studies of local 



marsh:water relationships, marsh breakup, 

 and plant diversity as thay relate to 

 waterfowl are rare. Perhaps this is 

 inevitable in a wetland area as large as 

 the Mississippi Delta. The availability, 

 in the past few years, of good remote 

 sensing data and new technologies to 

 process large data sets gives us the 

 capability of examining in much greater 

 detail the complex wi Idl ife:habi tat 

 rel ationships . 



In midwestern pothole marshes, habi tat 

 quality for wildlife is closely hound to 

 an approximate 10-year cycle of 

 energent-floating-submergent vegetation 

 succession that seems to be controlled bv 

 water levels and herbivory, especially 

 muskrat herbivory. In Louisiana's coastal 

 marshes, water levels controlled by the 

 level of the Gulf of Mexico arp more 

 stable in that time scale, and the 

 dominant trend is a long-tern (100+ year) 

 change from fresh to saline and from solid 

 marsh to broken-up marsh to open water. 

 However, within this long tine frame 

 O'Neil (1949) identified 10- to 14-year 

 cycles that are related to severe storms 

 and muskrat and goose "eat-outs." 



One 



the most 



Al 1 igators . 

 dramatic success stories in wildlife 

 conservation in Louisiana is the return of 

 the alligator from a threatened 

 classification (Endangered Species Tech. 

 Bull. 2(2), Feb. 1977) to the present 

 abundance that makes possible a controlled 

 harvest each year. The soecies was 

 threatened by severe hunting pressure, 

 not habitat loss. When that pressure 

 was removed, its numbers increased 

 rapidly. 



Alligators are abundant in fresh and 

 slightly brackish bayous and lakes. They 

 reach their highest densities in 

 internediate wetland zones (Joanen and 

 McNease 1972). They build nests in 

 marshes and on levees. One favorite 

 microhabitat is the wax myrtle thickets 

 canmon in fresh marshes. In 1982 we 

 counted 23 nests in a fresh floating marsh 

 fringing a small shallow lake; a night 

 count along a fresh marsh bayou revealed 

 over four alligators per km (Sasser et al. 

 1982). 



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