Appendix 6.3(2). Data acquisition for dominant species of the Chenier Plain. 



The first step in gathering data on higher vertebrates in the Chenier 

 Plain was to determine which species are known to occur there. This was ac- 

 complished by referring to range maps or species accounts published in the 

 following works: amphibians, Smith (1956), Wright and Wright (1949), Conant 

 (1975); turtles, Carr (1952), Conant (1975); alligator, Conant (1975); liz- 

 ards, Smith (1946), Conant (1975), Dundee and Rossman (unpublished ms.) ; 

 birds, Peterson (1963), Robbins et al. (1966); mammals, Hall and Kelson 

 (1959), Lowery (1974b). Range maps and discussions of geographic distribu- 

 tion are often based more or less on inference, and often vary among authors. 

 Exceptions to this are range maps for reptiles given in Rossman and Dundee 

 (unpublished ms.) and for mammals given in Lowery (1974b). Maps in these 

 two publications were compiled from documented occurrences of individuals at 

 specific localities within relatively recent historic times. Another short- 

 coming of range maps is that they present a static view of dynamic and com- 

 plex phenomena. Distributions of species are almost constantly changing, 

 either expanding (e.g. cattle egret) or contracting (e.g. whooping crane), 

 so these lists must be viewed as only preliminary. 



In an effort to determine representative species, those species whose 

 ranges were mostly outside the Chenier Plain and for which there were only 

 occasional records of occurrence in the area were omitted from the list. 

 Exceptions to this were species that are on the U.S. Department of the In- 

 terior's Endangered or Threatened list, or those whose populations are known 

 to be declining. Each year the National Audubon Society publishes a "Blue- 

 list" of bird species whose populations are declining in some part of their 

 geographic range. Though this may not apply to breeding populations in Lou- 

 isiana, most of these species occur in the Chenier Plain during spring and 

 fall migration and thus merit attention. For most of the remaining species, 

 there is virtually nothing known about population status in Louisiana. It 

 is likely that some of these would have endangered status if they were bet- 

 ter known. 



Basin Level - Occurrence of Species in the 14 Habitats 



These determinations were based on information gleaned from the above 

 publications and also from Lowery (1974a). In the absence of systematic 

 faunal surveys, habitats listed by the above authors for each species were 

 relied on. This often required some interpretation, and the assignment of 

 a species to a particular habitat was in no way rigorous. For example, 

 Peterson (1963) lists the following habitats for the least sandpiper: "mud- 

 flats, grassy marshes, prairie pools, shores". Lowery (1974a) lists "beaches, 

 mudflats, grassy meadows, muddy lakeshores" for this species. The least 

 sandpiper was then assigned to the following habitats as defined in the 

 Chenier Plain project: Inland Open Water, Beach, Salt Marsh, Brackish Marsh, 

 Intermediate Marsh, Fresh Marsh, and Pasture. A similar procedure was fol- 

 lowed for each species. 



continued 

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