LAGUNA ATASCOSA WILDERNESS STUDY AREA Laguna Atascosa National Wildlife Refuge Cameron and Willacy Counties, Texas WILDERNESS STUDY REPORT U. S. DEPARTMENT OF THE INTERIOR Fish and Wildlife Service Bureau of Sport Fisheries and Wildlife CONTENTS Preface ..................... I. Introduction .................. II. Objectives ... ................ 6 III. History ..................... A. Early Stage ................. 7 B. Conquest and Colonization .......... » C. Revolution and Republic ........... «J D. Texas in the United States ......... >4 IV. Land Status ................... 20 V. Physical Characteristics ............ 24 A. General ................... 24 B. Climate ................... 28 C. Geology ................... 29 D. Ecology . .................. 31 VI. Resources ............. • ...... 35 A. Wildlife .................. 35 1. Manuals ................. 35 2. Birds . ................ 36 3. Reptiles and Amphibians ......... 41 4. Fish .................. 44 B. Wetlands .................. 45 C. Vegetation and Soils ..... ....... 47 D. Mineral ............ ....... 61 E. Recreation ................. 62 VII. Socio-Economic Considerations ......... 66 A. General .......... ......... 66 B. Grazing ................... 68 C. Navigation ................. 69 D. Agriculture ................. 69 VIII. Development . .......... .' ...... ;g IX. Management .... .......... ,-. 74 A. Wildlife and Vegetation ....... 7/1 B. Minerals - Mining ....... 4 ] * " 74 C. Recreation ....... - ° * 7fi D. Navigation ........ ] .'.'.';!!.' I 76 X. Summary and Conclusions . , , . .««••.., . /y7 0i, Appendix I .*.... * ...... ...... 83 PREFACE The following report is presented in fulfillment of the require- ments of the Wilderness Act (P.L. 88-577). The Laguna Atascosa National Wildlife Refuge, located in southern Texas, is a biotic community representative of the South Texas Coast. The entire refuge was examined for its wilderness potential. Artificial impoundments, farming for wildlife, improved pastures and public use facilities eliminated from consideration all but the northern one-fifth of the refuge. This unit, North Island, consists of tidal flats, low vegetated ridges and old stream channels. Nu- merous species of plants and animals are present, many occurring in the United States only in southern Texas. The complex community is a seeming fusion of seashore, desert and subtropical elements. In view of rapidly disappearing coastal waterfowl habitat and the important role the refuge assumes in providing such habitat, the va7ue of North Island was also considered in this respect. The old stream channels and adjacent ridges interlace to provide considerable potential for fresh water impoundments. The refuge Master Plan rec- ognizes this potential and recommends that such potential be developed. While North Island meets the qualifications of the Wilderness Act and thus must be found suitable for consideration, wilderness designa- tion would preclude full development for wildlife. iii I. INTRODUCTION Laguna Atascosa National Wildlife Refuge is located on the South Texas Coast about 25 miles north of the Mexican border (Figure 1). The eastern boundary of the refuge fronts on the Laguna Madre, a large, shallow, 100-mile-long embayment formed by Padre Island and lying along the Texas Coast from Corpus Christi to the mouth of the Rio Grande. The refuge was established in 1946 when the first tract of land was purchased with Duck Stamp monies. It is the southernmost link in the chain of waterfowl refuges along the Central Flyway and contains 45,050 acres, including about 7,000 acres of marsh and open water and 14,600 acres of mud flats. Its name is derived from its largest lake, Laguna Atascosa. A headquarters is situated on the refuge and an office is maintained in the town of San Benito about 25 miles southwest. U. S. Highway 77, the main coastal route, passes through San Benito. Other nearby towns of importance include Rio Hondo, 12 miles; Harlingen, 27 miles; and Brownsville, 25 miles from the refuge. The Harlingen Ship Chan- nel bisects the refuge into two unequal parts. The main channel of the Intracoastal Waterway skirts the refuge a short distance offshore in the Laguna Madre and a small stretch crosses the refuge on the northeastern tip. The major objective of the refuge is to develop, maintain, and manage waterfowl habitat to support up to 500,000 ducks and 20,000 geese. LAQUMA ATASCOSA ' NATIONAL. WU-.DL-IRE WILLACV CAMERON co IMPKOVEO DI»T UNIMPROVED COUNTY L.INE BOONOAieY MUD WATER HOLE - txCAVA-re Other objectives are: To preserve habitat for animals rare or en- dangered in the United States; to provide for public use and enjoy- ment of the wildlife resource; and to manage for the greatest number of migratory and indigenous species within the capabilities of available habitat. For management purposes the area is divided into eight units (Figure 1). All units except Unit IV are south of the Harlingen Ship Channel. Unit I (1,385 acres) is separated from the rest of the refuge by a paved road. It is a scenic walk-in area. Units II and III (15,930 acres) include almost 6,000 acres of water surface. They contain the bulk of the high-quality waterfowl habitat. A guided-tour road traverses the length of Unit II. Additional developments for waterfowl are planned including an impoundment between Cayo Atascoso and the Harlin- gen Ship Channel. Unit IV, North Island (9,440 acres), is isolated from the rest of the refuge by the ship channel. The only surface access is by boat. There are no roads and virtually no developments on the.area. Developments for waterfowl are planned. Unit V, Horse Island (3,770 acres), fronts on the Laguna Madre and the Harlingen Ship Channel. It is proposed to operate this unit as a saline habitat with an impoundment to provide resting habitat for water birds. Units VI and VIII (6,040 acres) contain 1,500 acres of farm- lands, 400 acres of improved pastures and headquarters facili- ties. They contain the primary deer and goose browse areas. Unit VII (8,485 acres), once part of a military gunnery range, contains a self-guided auto tour. Some evidence of military occupation still remains. It is planned to further develop this unit to the extent that water supplies will permit. The auto tour will also be more fully developed. Unit IV, North Island (Figure 1), is the only roadless area of 5,000 acres or more on the refuge. The relative lack of development and the isolation coupled with the nearly "natural" aspect of the.land- scape combine to qualify this tract for consideration as a wilderness area. The remainder of the report deals primarily with this area. Unit IV is hereafter referred to as North Island (Figure 2). Figure 2. North Island is representative of the South Texas coastal community and is the only sizable, road- less and undeveloped block of land on the refuge. II. OBJECTIVES The objectives of this study are to gather and present for review such information as necessary for determining the suitability or non-suitability of portions of the Laguna Atascosa National Wild- life Refuge for inclusion in the National Wilderness Preservation System under Public Law 88-577, the Wilderness Act. III. HISTORY A. Early Stage Excavations in several northern counties reveal the existence of man in Texas at least 12-15,000 years ago. Archaeology suggests that a basic way of life was typical over a wide area and a long period of time^and was also similar to patterns to the south in Mexico. The manifestations are probably derived from the Desert Culture. It would appear that assemblages of the early stage were inland and represented hunting-collecting peoples in small to large groups having an essentially nomadic way of life. Later peoples occupied the coastal zone and relied considerably more on sea- food. Although precipitation is not unusually low on the coast, it is spasmodic and not seasonally patterned to farming without irrigation. In the absence of agriculture the native peoples depended on a variety of natural resources. Along the shore, fish and shellfish were caught; inland the diet consisted of seeds, nuts, fruits and roots. Hunting was pursued throughout the area. The middle or Archaic State is marked by the advent of ceramics and small arrow points. Shoreline cultures of this stage were represented by small nomadic bands with widespread contact with other, often larger, groups inland and along the Rio Grande. Pottery was almost certainly not a local product but a result of trade with more developed neighbors to the south. It is most likely that these phases relate to the historic Coahuiltec Indians. Coahuiltec is a name adopted to include a group of small, supposedly cognate tribes on both sides of the Rio Grande. The name is geographic rather than ethnic. The Historic stage saw a general breakdown in native Indian cul- ture when European colonization was seriously undertaken. The aboriginal population, sparse to begin with and not accustomed to political or religious domination or a sedentary way of life, did not adapt well to mission induction of the Spanish ecomienda system. Disease, intertribal strife and abandonment of native crafts all contributed to the cultural decline, and by the 1850's the remaining groups had retreated across the Rio Grande to Mexico. There is some disagreement concerning the area occupied by the cannibalistic Karankawa Indians. The literature suggests that this colorful group centered along the coast from Galveston to Corpus Christi, although there are reports of occupation along the entire