hurricanes, usually in late summer and early fall, biases the 

 annual average upwards. Without this boost, the averages would be 

 lower and more indicative of the stress associated with semiarid 

 lands where droughts are frequent but irregular (Carr, 1966) . 

 Average temperature for Corpus Christi, the nearest station with 

 longtime weather data is 71.7° Fahrenheit (21.7° Celsius); average 

 precipitation is 26.72 inches (678 millimeters) (Department of 

 Commerce, 1970) . 



Two principal wind regimes dominate the Texas coastal zone- 

 persistent, southeasterly winds from March to September, and north- 

 northeasterly winds from October to February (Behrens, Watson, 

 and Mason, 1977) . However, prevailing winds (disregarding wind- 

 speed) are onshore 11 months of the year (Dahl, et al . , 1975). 

 Northerly winds are associated with frontal passages and are 

 usually strong with concurrent precipitation. However, some 

 northers are dry, building small dunes along the beach with each 

 passage. Prevailing winds then transport this sand back to the 

 foredunes . 



The coastal topography of the mainland and adjacent to Padre 

 Island is relatively flat with soils developed from Pleistocene 

 and recent unconsolidated clastic sediments. The soils of Padre 

 Island developed on recent marine and eolian soils. Sand particle 

 size is dominantly fine to very fine sand. It is highly variable 

 in salt content with varying amounts of shell and organic matter. 

 The highest organic matter content from beach sands was 0.1 

 percent. Shell fragments were mostly less than 1 percent (Dahl, 

 et al., 1975). 



A schematic cross-sectional profile of north Padre Island 

 and the dominant plants of major communities are shown in Figure 

 2. North Padre Island is predominantly grassland of midheight. 

 Seacoast bluestem {Schizaohyriim soopariim var. littopalis) , 

 seashore dropseed (Sporobolus virginious) , gulfdune paspalum 

 [Paspalum monostaohywri) , and saltmeadow cordgrass (Sparti-na 

 patens) are species that commonly occur from the foredune across 

 the island. 



The number of species on the shoreface of the dunes is limited, 

 with sea oats {Uniola paniculata) the dominant sand-trapping plant. 

 Other species capable of trapping or binding sand are saltmeadow 

 cordgrass, seashore dropseed, bitter panicum {Pani-Gum amcanm) , rail- 

 road vine (Ipomoea pes-oaprae) , and gulf croton {Croton punatatus) . 

 After dunes have been started by pioneer vegetation, forbs such as 

 beach groundcherry [Physalis viscosd) , beach evening primrose 

 [Oenothera drwnmondii) , and prairie senna {Cassia fascioulata) 

 often become common. 



