broad overwash; (b) planting on fence-built sand dunes; and (c) use of irrigation and burlap 

 mulching in conjunction with beach and dune plantings. The most useful areas for 

 harvesting sea oats seed were from isolated clumps in the midst of a barren dune field. Insect 

 and ground squirrel use was so pronounced in areas of continuous vegetation that little 

 viable seed could be obtained. Even isolated clumps downwind of a large vegetated area 

 showed moderate insect use. Harvested inflorescences were stored in burlap bags suspended 

 from a ceding in an enclosed warehouse at ambient temperatures. Seed heads were threshed 

 by hand to the spikelet and stored in burlap bags in the warehouse until planted. 



Comparison between the 1970-71 and 1971-72 plantings show a 3-week difference in 

 seedling emergence— during the first week in June 1970-71, and the second week in May 

 1971-72. This difference apparently corresponded to the difference in available soil 

 moisture between years. Even with more favorable environmental conditions in 1971 and 

 1972, emergence was too sporadic to ascertain conclusive results, but they did reveal other 

 problems in direct seeding methods. They were: 



(a) Seeding attempts on elevated surfaces, such as fence-budt dunes and without 

 irrigation and burlap, yield few seedlings due to wind erosion of seeds. Frequent drying 

 of the surface sand also prevents germination. 



(b) Burlap covering of seed on elevated slopes stabilized the sand but did not 

 sufficiently retard surface water loss. Irrigation in conjunction with burlap covering did 

 not produce a stand of grass due to the low germination rate of sea oats seed. 



(c) Seeding was more successful behind fence-budt dunes where seeds were 

 protected from saltwater inundation and shifting sand. Best stands resulted when seed 

 was broadcast at high rates, covered with burlap, and irrigated when the surface sand 

 dried out. 



(d) Since two growing seasons are required for full establishment of sea oats 

 seedlings, but only one-half year for transplants, direct seeding is not useful on critical 

 areas such as fence-built dunes, and is not recommended for beach plantings for the 

 same reasons. 



b. Mode of Propagation: Vegetative Transplants. All of the successful experimental 

 dunes were established with vegetative transplants, dug from a nursery or from wdd stands 

 and replanted on the beach sites. 



c. Source of Transplants: Wild Stands. Both bitter panicum and sea oats transplant 

 stock may be acquired successfully from naturally occurring stands. At the start of tlus 

 study, bitter panicum was scarce on north Padre, and establishment of a nursery was 

 necessary to ensure enough material. However, adequate wdd stock of both species now 

 exists on both ends of the island. Tire most suitable site for obtaining wdd sea oats culms is 

 from an early successional, young deflation plain, where sea oats seedlings are established 

 and growing as clumps. Such a site has a limited amount of blowing sand, so that the culms 

 are usually not deeply seated. The poorest site is the foredune, since accumulating sand 



71 



