burning, drought, and hurricanes lias altered the species composition and reduced cover. A 

 hint of the rapid recovery possible with the exclusion of cattle is reported by Price (1971) in 

 comparing a photo of a 1-acre cattle exclosure with adjacent heavily grazed grassland on 

 northern Padre. After only 10 months, the exclosure had a well developed stand of grass 

 (apparently saltmeadow cordgrass), wliile the grazed part was mostly barren. Combined 

 effects of burning and overgrazing on some east coast barrier islands have been denudation 

 and activation of shifting, barren dunes, which previously were vegetated and stable 

 (Oosting, 1954). 



Construction of a causeway in 1927 connecting northern Padre Island with the mainland 

 brought tourism to the island. Developers interested in the tourist potential sought new 

 causeways and legal title to tiie island. In the 1950's, with the opening of new causeways at 

 each end of the island, land investment increased with development of parks, hotels, and 

 homes. 



The National Park Service recommended Padre Island as a national seashore, and in 

 1963, following approval from Congress and later transfer of State lands and acquisition of 

 private property, Padre Island National Seashore was established. The national seashore 

 extends from about 10 miles south of the northern end of the island to Mansfield Channel 

 (62 miles), and an additional 12 miles south of the channel (beach strip only). Private 

 development of the extreme ends of the island is continuing rapidly, and a community of 

 about 50,000 persons is planned for the north end (Price, 1971). However, the national 

 seashore, comprises more than half of the island and is mostly undeveloped, except for 

 Malaquite Beach near the north end of the park. Since 1963, several million tourists have 

 visited the national seashore, including nearly one million in 1973. Visitors are expected to 

 increase as land bordering the park becomes further developed. 

 2. Geological Processes of Padre Island. 



a. General Processes. The barrier islands of the gulf coast have been formed by natural 

 processes (water and wind) transporting and depositing sand. The specific origin of barrier 

 islands is a source of controversy. An early theory of upward building of offshore bars to 

 become islands has been questioned by Hoyt (1967) and Fisher (1968). Instead, Hoyt 

 proposed a theory of relatively rapid submergence of a mainland shoreline with a well 

 developed dune ridge. Fisher disagreed with this hypothesis, and postulated that barrier 

 islands originated predominantly as complex spits under the action of longshore currents. 



Padre Island began forming about 4,500 years ago, when the modern standstill of sea 

 level was established from a previously rising sea level associated with the melting of 

 continental glaciers (Bernard and LeBlanc, 1965). The islands grew seaward bv beach and 

 shoreface accretion: and landward into the bavs by washover of sand during hurricanes and 

 by eolian drift of sand (Hayes, 1967). Deposition of sediments during storms occurs from 

 the storm surge floodtide, and also from the surge ebbtide (Andrews. 1970). 



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