Biological Flora of Coastal Freshwater and Brackish Marshes: Cladium jamaicense Crantz

Cladium jamaicense Crantz, also known as sawgrass, has a broad distributional range from the Atlantic coast of Virginia to Florida, to southern Texas, the Caribbean, and along the Atlantic coast of Mexico to Central America, and to Brazil. Cladium jamaicense typically occurs in oligotrophic sloughs and fresh and brackish marshes where optimal salinity values range from 0 to 3.5 ppt. This species is a long-lived perennial with a highly developed rhizome system with rhizomes up to 20 cm long and 2.5 to 10 mm in diameter. Asexual reproduction is common. Its fibrous root system comprises short dauciform roots characterized by a dense number of long root hairs. Culms are 1.0 to 3.0 m tall. Leaf blades are coarse, flat, or broadly involute; leaf margins and the abaxial midvein have sharp, hacksaw-like teeth. Typha domingensis (cattail) is C. jamaicense’s most important competitor, especially in sites that have been enhanced with phosphorus. Restoration of sawgrass marshes requires managing long-term changes in ecosystem functions and hydrological management strategies

Biological Flora of Coastal Wetlands: Sporobolus cynosuroides (L.) P.M. Peterson & Saarela

Sporobolus cynosuroides (L.) P.M. Peterson & Saarela¼Spartina cynosuroides (L.) Roth is a temperate zone rhizomatous grass that often is a dominant species in coastal brackish marshes on the Gulf coast and Atlantic coasts of the United States where salinity ranges from 0 to 10 psu. Sporobolus cynosuroides (L.) P.M. Peterson & Saarela ¼ Spartina cynosuroides (L.) Roth is usually absent where salinity values are .12 psu. Sporobolus cynosuroides occurs in coastal habitats characterized by infrequent tidal flooding and moderate nutrient levels. Also known as big cordgrass, it may account for net productivity in high marshes that rivals productivity of Sporobolus alterniflorus ¼ Spartina alterniflora the dominant species in saline low marsh environments. Sporobolus cynosuroides and a limited number of cohorts are threatened by climate change and rising sea levels. This species provides important ecological services. In addition, S. cynosurodes provides cover and nutrition for wildlife, and has fair forage potential for livestock

Effects of a Severe Freeze on Native Woody Plants in the Lower Rio Grande Valley, Texas

The effects of a severe freeze in December, 1983 on the native plants of the lower Rio Grande Valley, Texas were determined for 75 species. Damage was initially assessed by examining leaves, apical meristems, and cambial tissues of stems. Initial assessments were confirmed by surveys in the spring when new leaves were present. Forty-three species were either undamaged or had only minor leaf damage. Twenty-two species with damaged leaves had intact apical meristems or showed evidence of damage for less than 10 cm below the apical meristem. Three species, Leucaena pulverulenta, Cordia boissieri, and Karwinskia humboldtiana, had more extensive damage, i.e., 10 cm - 40 cm below the apex, but showed evidence of recovery by the presence of undamaged cambial and phloem tissues below the apex. Eight species, Avicennia germinans, Capsicum annuum var. glabriusculum, Cereus pentagonus, Chiococca alba, Citharexylum berlandieri, Erythrina herbacea, Iresine palmeri (male plants), and Petiveria alliacea, were seriously damaged. Temperatures lower than those occurring in December, 1983, or similar temperatures for much longer periods of time, would be necessary to kill most of the native species in the lower Rio Grande Valley, Texas

Riparian Vegetation of the Lower Rio Grande

The riparian vegetation of the lower reach of the Rio Grande was studied at 7 locations using 3 line intercepts at each location. There were no trees at the mouth of the river and the vegetation was similar to that found along the Laguna Madre shore of barrier islands. Mesquite (Prosopis glandulosa) was the dominant tree near the coast and in the western section of the river near Falcon Dam. Sugar hackberry (Celtis laevigata) was the dominant tree species at all other sites except at Santa Ana National Wildlife Refuge, where cedar elm (Ulmus crassifolia) and anacua (Ehretia anacua) were the dominant trees. Granjeno (Celtis pallida) was a dominant shrub throughout the riparian corridor. The dominant trees and shrubs appeared to be replacing themselves. Species similarity in the tree, shrub, and ground layers was greater among transects at a given site than between sites. The introduced Guinea grass (Panicum maximum) and buffel grass (Pennisetum ciliare) were the dominant species in the ground cover, displacing native species. - La vegetación riparia de la sección baja del Río Bravo fue estudiada en siete localidades utilizando tres líneas de intercepción en cada localidad. No hay árboles en la desembocadura del río y la vegetación es semejante a la de la orilla de las islas barrera de la Laguna Madre. Mesquite (Prosopis glandulosa) es el árbol dominante cerca de la costa y en la sección occidental del río cerca de la Presa Falcón. El palo blanco (Celtis laevigata) es la especie de árbol dominante en todos los demás sitios excepto en el Refugio Silvestre Nacional de Santa Ana donde el olmo (Ulmus crassifolia) y la anacua (Ehretia anacua) son los árboles dominantes. Granjeno (Celtis pallida) es el arbusto dominante en todo el corredor ripario. Parece que los árboles y arbustos dominantes se están reemplazando. La semejanza de especies entre árboles, arbustos y cobertura de tierra es más alta entre transectos en un sitio que entre sitios. Las hierbas exóticas, Panicum maximum y Pennisetum ciliare, son las especies dominantes de la superficie terrestre, desplazando a las especies nativas

Phytogeography of South Padre Island, Texas

The phytogeographic affinities of the native flora of South Padre Island, Texas, are analyzed and the probable dispersal agent(s) for each species identified. The native flora consists of 99 species and 44% of the species also occur on the adjacent Texas mainland; 28% of the native species have tropical affinities. Only three species have probably dispersed from the island to the mainland. Two species may be endemic to Padre Island and the Tamaulipan barrier islands. Most of the tropical species have reached the island by oceanic drift, but birds are the most important dispersal agent for the native species. Man is responsible for the introduction of 117 species

Comparison of the Effects of the Severe Freezes of 1983 and 1989 on Native Woody Plants in the Lower Rio Grande Valley, Texas

Freeze damage to native woody plants was assessed at the same four sites in the lower Rio Grande Valley, Texas, in 1983 and 1989. The number of severely damaged species was greater in 1989 possibly because temperatures in 1989 were lower and longer in duration below freezing versus 1983. Thirty0five species (48.6%) had the same damage index value for the two freezes, and 24 (33.3%) species showed no damage in either year. More than half of the 72 species analyzed (55.5% in 1983 and 51.3% in 1989) showed no damage or only leaf damage, indicating most of the native woody species are well adapted to survive periodic freezes. In 1989, Avicennia germinans, Cordia boissieri, Leucaena pulverulenta, Karwinskia humboldtiana, and Pithecellobium pallens included individuals killed to their bases. Heights of some of the L. pulverulenta exceeded 10 m. All species showed evidence of recovery by spring 1990

Annotated Checklist of the Flowering Plants of South Padre Island, Texas

This study catalogues the flowering plants of South Padre Island, Texas. A total of 207 species in 47 families is listed. The abundance and ecological distribution of each taxon are noted. Comparisons are made with the flora of Mustang Island, Texas. Ninety-three species, 96 genera and 36 families are common to both islands. Three families, Compositae, Gramineae and Leguminosae, contain large shares of the total number of species on both islands. Apparently, much of the floral diversity is due to the presence of a large number of species that are represented by small populations

Cissus sicyoides C. Linnaeus (Vitaceae), a Potential Exotic Pest in the Lower Rio Grande Valley, Texas

English:Cissus sicyoides C. Linnaeus, a perennial vine native to tropical Mexico, Central America, and the Caribbean, has recently been rediscovered in the Lower Rio Grande Valley,Texas. A dense population of this exotic species has been located in a brushy area along a canal network and in two adjacent citrus groves near Weslaco. This species produces a dense mantle that covers other vegetation, appears to be invasive, and may pose a potential weed problem in citrus in the Lower Rio Grande Valley. Spanish: Cissus sicyoides C. Linnaeus, una enredadera perene nativa de los trópicos de México, América Central y el Caribe, se ha redescubierto recientemente en el Bajo Valle del Río Grande,Texas. Una población densa de esta especie exótica ha sido localizada en una área de matorral a lo largo de una red de canales y en dos huertas adyacentes de cítricos cercanas a Weslaco. Esta especie produce un manto denso que cubre otra vegetación, es invasiva y puede tener el potencial de convertirse en una maleza problemática para el cultivo de cítricos en el Bajo Valle del Río Grande en Texas

Recovery of vegetation following a wild fire on the margins of tidal flats, Padre Island National Seashore, Texas

Recovery of halophytic vegetation on the margin of tidal flats following a wildfire at Padre Island National Seashore, Texas, was studied for 26 months. Species richness, species diversity, species importance, evenness and vegetation abundance were evaluated. Species richness and diversity were restored within 108 days after the fire. Sporobolus virginicus was the dominant species on both burned and non-burned transects. Vegetative cover was slow to recover. It took 19 months for cover of burned areas to equal or exceed cover of non-burned areas. Biomass also was slow to recover and it did not equal biomass of non-burned transects in 26 months. Species colonizing the burned transects were mostly species in nearby non-burned areas. Only one exotic species (Polypogon monspeliensis) appeared in the burned transects. The principal way that fire affected the tidal flats community was in the reduction of standing dead plants and surface litter