Generally, the response of bitter panicum transplants to the environment was similar to 

 sea oats. High salinity and low moisture resulted in low survival, but the transplants 

 appeared to do better when the carbohydrate content was low. In combination with other 

 variables, temperature was occasionally important to bitter panicum survival but significant 

 patterns were harder to define. 



Shoredune panicum was planted only in 1971-72, and the influence of environmental 

 factors on survival was similar to the other two species. Multiple correlation analyses are 

 included in Table 27. 



Brown and Hafenrichter (1948a) also found environmental parameters important to 

 transplant survival for species on Pacific coastal sand dunes. Over 50 percent survival for 

 European beachgrass was always obtained when maximum air temperatures did not exceed 

 55° Fahrenheit for 3 days after planting; survival was always less than 50 percent when 

 maximum temperatures exceeded 60° Fahrenheit. Dormancy of American dunegrass 

 transplants was more important to survival than environmental variables. American 

 beachgrass was less sensitive to either climate or dormancy, and hence was the best choice 

 for transplanting on Pacific coastal dunes. 



To further assess the influence of periodically liigh salinities on plant survival, monthly 

 plantings of sea oats and bitter panicum were made at open and protected beach sites on 

 north and south Padre in 1973-74. Open beach sites were similar to those of previous 

 monthly and major plantings. Soil moisture was usually high, but sahnity varied from low to 

 high as a result of periodic saltwater inundations and heavy salt spray; plantings were also 

 subject to burial by drifting sand. Protected beach plantings leeward of an artificial dune 

 line were protected from saltwater inundation, drifting sand, and some salt spray. Culms for 

 each paired planting were obtained from the same location, thoroughly mixed, and 

 transplanted the same day. Survival comparisons are given in Table 30. 



Protected beach transplant survival for both species was consistently higher in all 

 months. Multiple and single correlation analyses (Table 31) showed that no single factor 

 including salinity was responsible for this difference. 



On north Padre, soil salinity of the open beach was greater than the protected site. 

 However, soil salinities of the two south Padre sites were more comparable. Soil moisture, 

 rainfall, TAC, soil, and air temperatures were similar or equal for each pair of open and 

 protected sites for a given planting. This suggests that some unmeasured variables (probably 

 salt spray and drifting sand) were adversely affecting the open beach transplants. The 

 survival potential, as exhibited by the protected plantings, was considerably higher and with 

 less variation than was realized on the open beach. 



Inundation by saltwater soon after planting, particularly in conjunction with drought, 

 caused complete or nearly complete failures of some monthly test plantings and of several 

 major plantings on south Padre (Table 11). Minor surges are common in winter and spring, 

 and any winter beach planting of less than 5 feet MSL is vulnerable to inundation. Minor 



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