c. Exotic Species. Several exotic species were tested, through the courtesy of the 

 U.S.D.A. Soil Conservation Service Plant Materials Centers at Pullman, Washington; 

 Experiment, Georgia; and Knox City, Texas. Both seeds and plants were obtained for trial 

 plantings. Results from the plantings were mostly negative (Table 12). No plants emerged 

 from the seeds except for one species native to the area, Indigofera miniata (synonym is 

 /. leptosepala). Survival of transplants was variable and those surviving lacked vigor except 

 for the Japanese wild indigo (Indigofera pseudotinctoria). Of all lots received, only the 

 Japanese wild indigo shows promise as a sand trapper or binder on Padre Island. Further 

 evaluation of exotic plants was terminated in 1972 by landfill operations of the Padre Island 

 Investment Corporation. Other plants received during 1971 were planted on backshore areas 

 near the north Padre 1,200-foot sea oats plot. Saltwater inundation and sand abrasion 

 prevented these species from becoming established. 



American beachgrass (Ammophila breviligulata), a cool season grass used widely on the 

 east coast for dune stabilization, has been successfully introduced from a more northern 

 range into the Carolinas and used as an exotic for dune construction (Woodhouse and 

 Hanes, 1967; Graetz, 1973). In 1970, transplants supplied by the North Carolina State 

 University, Raleigh, North Carolina, were planted on Padre Island. The south Padre plants 

 died within a short period, while on north Padre some plants persisted nearly 2 years before 

 succumbing. Apparently, the hot and dry south Texas climate was unsuitable for American 

 beachgrass. European beachgrass (A. arenaria) was tested on PAIS by Tauscher (1966). 

 Early results were generally successful, and a few individual plants persisted for over 5 years. 



Additionally, 113 plants of Scaevola Thunbergii (an exotic forb) were supplied in 1972 

 by the New Crops Research Branch, Agricultural Research Services, U.S.D.A., Beltsville, 

 Maryland. The plants were transplanted to protected sites in the north and south parts of 

 the island. After 2 years, three plants are still living on north Padre, and appear healthy 

 although growth is slow (all are less than 2 feet high). A native species of this genus 

 (S. Plumieri) is rare in this area, but one sizable clump on a north Padre foredune shows it 

 may be useful as a dune-builder. These trials concluded that none of the exotic species 

 tested was suitable for dune construction. 



d. Indigenous Species. Testing the four most promising grasses by monthly plantings to 

 determine survival rates and block (50 by 50 feet) plantings to assess dune-building 

 potential, was started in 1969 (Table 13). Two species, seashore dropseed and saltmeadow 

 cordgrass, were later eliminated. Although successfully transplanted, seashore dropseed 

 lacked adequate sand-trapping potential; poor survival, lack of vigor, and less than optimum 

 sand-trapping capability eliminated saltmeadow cordgrass. Saltmeadow cordgrass is very 

 salt-tolerant, but also has a high moisture requirement (Oosting and Billings, 1942), and 

 grows most successfully on low dunes and the backshore. 



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