Figure 60. A muskrat "eat-out" in the brackish marsh in the Barataria basin. Note the 

 high density of muskrat houses (Photograph by Robert Abernathy). 



of herbivory. Huskrats are reported to 

 eat one-third of their weight per day 

 (O'Neil 1949), and a nutria consumes 1.5 - 

 2 kg of vegetation each day (Lowery 1974). 

 The average population of nutrias and 

 muskrats from Point au Chien Wildlife 

 Management Area in the delta, from 1973 to 

 1981, was 1.2 and 0.8/ha, respectively 

 (from Sasser et al. 1982, assuming the 

 population is double the catch (O'Neil 

 1949). 



If a nutria eats 2 kg/day, a muskrat 

 0.3 kg/day (a muskrat weighs about a 

 kilogram), and the vegetation is 20 

 percent dry weight, then their combined 

 intake is about 150 kg/ha/yr, compared to 

 a plant productivity of about 30,000 

 kg/ha/yr. Direct grazing is thus less 

 than 1 percent of production. O'Neil 

 (1949) reported a peak harvest of 46 

 muskrats/ha in a brackish marsh (Figure 

 59). With the same assumptions, that many 

 animals would eat as much as 7 percent of 

 the vegetation. If damage from burrowing. 



building nests, and digging for roots was 

 10 times greater than ingestion, it is 

 easy to see that a significant portion of 

 the vegetation would be destroyed. 



Deer . Although one-third of 



Louisiana's white-tailed deer (Odocoileus 

 virqinianus ) population is reported to 

 live in the coastal marshes (which 

 comprise only 13 percent of the state) 

 (St. Amant 1959), very few studies have 

 been made of their feeding and habitat 

 requirements in this environment. 



Apparently, fresh marshes are preferred 

 almost to the exclusion of brackish and 

 sal ine marshes . 



Based upon data gathered over 20 

 years, J. B. Kidd (La. Wildlife and 

 Fisheries Commission), in a 1972 letter 

 (as reported in Self 1975), estimated that 

 the "potential" density of deer by marsh 

 type was one deer per 12 ha in the fresh 

 marsh, 1 per 330 ha in the brackish marsh, 

 and 1 per 2900 ha in the salt marsh. This 



67 



