Frank W. Judd

Comparison of methods for determining low temperature tolerance: experiments with pinfish, Lagodon rhomboides

RANDALL, J. E. 1965. A review of the razorfish genus Hemipteronotus (Labridae) of the Atlantic Ocean. Copeia 1965:487-501. , AND R. H. KUITER. 1982. Three new labrid fishes of the genus Coris from the Western Pacific. Pac. Sci. 36:159-173. ROSENBLATT, R. H., AND B. W. WALKER. 1963. The marine shore-fishes of the Galaipagos Islands. Occ. Papers California Acad. Sci. 44:97-106. THOMSON, D. A., L. T. FINDLEY, AND A. N. KERSTITCH. 1979. Reef fishes of the Sea of Cortez. John Wiley and Sons, New York, New York. VICTOR, B. C. 1986. The duration of the planktonic larval phase of one hundred species of Pacific and Atlantic wrasses (Family Labridae). Mar. Biol. 90: 317-326. . 1987a. The mating system of the Caribbean rosy razorfish, Xyrichtys martinicensis. Bull. Mar. Sci. 40:152-160.

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.

Using High Resolution Satellite Imagery to Map Black Mangrove on the Texas Gulf Coast

Abstract QuickBird false color satellite imagery was evaluated for distinguishing black mangrove [Avicennia germinans (L.) L.] populations on the south Texas Gulf Coast. The imagery had three bands (green, red, and near-infrared) and contained 11-bit data. Two subsets of the satellite image were extracted and used as test sites. Supervised and unsupervised image analysis techniques were used to classify the imagery. For the supervised classification of site 1, black mangrove had a producers accuracy of 82.1% and a users accuracy of 95.8%, whereas for the unsupervised classification, black mangrove had a producers accuracy of 100% and a users accuracy of 60.9%. In the supervised classification of site 2, black mangrove had a producers accuracy of 91.7% and a users accuracy of 100%, whereas in the unsupervised classification, black mangrove had a producers accuracy of 100% and a users accuracy of 85.7%. These results indicate that QuickBird imagery combined with image analysis techniques can be used successfully to distinguish and map black mangrove along the south Texas Gulf Coast.

Use of Archive Aerial Photography for Monitoring Black Mangrove Populations

Abstract A study was conducted on the South Texas Gulf Coast to evaluate archive aerial color-infrared (CIR) photography combined with supervised image analysis techniques to quantify changes in black mangrove [Avicennia germinans (L.) L.] populations over a 26-year period. Archive CIR film from two study sites (sites 1 and 2) was studied. Photographs of site 1 from 1976, 1988, and 2002 showed that black mangrove populations made up 16.2%, 21.1%, and 29.4% of the study site, respectively. Photographs of site 2 from 1976 and 2002 showed that black mangrove populations made up 0.4% and 2.7% of the study site, respectively. Over the 26-year period, black mangrove had increases in cover of 77% and 467% on sites 1 and 2, respectively. These results indicate that aerial photographs coupled with image analysis techniques can be useful tools to monitor and quantify black mangrove populations over time.

Factors Affecting the Low-Temperature Tolerance of Texas Pinfish

Abstract Laboratory experiments were conducted to determine the effects of rate of temperature decrease, acclimation time, acclimation temperature, and seasonal changes on the low-temperature tolerance of pinfish Lagodon rhomboides. The critical thermal minimum (CTMin) was insensitive to rates of temperature decrease between 0.5°C/h and 1.5°C/h but was linearly correlated (r = 0.984) with acclimation temperature, When water temperatures were decreased at 1.0°C/h, the mean CTM in of pinfish acclimated at 24.0°C was 3.4°C. Acclimation adjustments in CTM in for fishes transferred from 22.0°C to 11.7°C were complete within 5 d. Indeed, coldtemperature acclimation was 80% complete in 30 h. Seasonally acclimatized pinfish had mean CTM in values ranging from 0.5°C (January) to 5.3°C (July). Responses of pinfish to cold temperature in the laboratory may explain variations in mortality seen in natural pinfish populations during episodes of extreme cold.

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. A series of barrier islands comprise the predominant land form along the Gulf Coast of Texas. Padre Island is the longest of these barrier islands. It extends approximately 182 km from Corpus Christi on the north to the BrazosSantiago Pass at Port Isabel on the south. The Mansfield Channel separates the northern two-thirds of the island from South Padre Island. The flora and vegetation of South Padre Island is relatively well known compared to other areas of the barrier island chain (Dahl et al. 1974, Judd et al. 1977, Lonard et al. 1978). Lonard et al. (1978) reported that the vascular flora consisted of 209 species in 47 families and suggested that much of the floral diversity is due to the presence of a large number of species that are represented by small populations. Judd et al. (1977) provided information on the pattern of vegetation in relation to topography and reported that the vegetation occurs in distinct zones that correspond closely to topographic facets. Information on the geographic affinities of the flora is currently lacking. Although the mechanism(s) involved in the origin of the barrier islands is a subject of considerable controversy, workers agree that Padre Island began forming about 4,500 years ago (Dahl et al. 1974). Thus, the flora is post Wisconsin glaciation. Because of the proximity of Padre Island to the Texas mainland (maximum width of the Laguna Madre is about 16 km) and because of the length of the island, one might reasonably expect that many of the species present have been derived from the mainland. However, similar islands occur in the Gulf of Mexico south of Padre Island to Altimira, Tamaulipas, Mexico, 402 km south of Brownsville, Texas. These islands provide an avenue of northward dispersal for numerous organisms. Also, the longshore current is from south to north along South Padre Island and the Mexican barrier islands. Thus, species dispersed by drift would likely have tropical 313 NOVEMBER 14, 1980 This content downloaded from 207.46.13.57 on Thu, 08 Sep 2016 05:01:42 UTC All use subject to http://about.jstor.org/terms affinities. Furthermore, South Padre Island is situated in the flyway of many migratory birds that winter in Mexico and Central America. The purpose of this paper is to analyze the phytogeographic affinities of the flora of South Padre Island and to identify the major dispersal agents. This information should facilitate understanding the floristic relationships of Gulf Coast barrier islands in particular and contribute to knowledge of barrier island ecology in general. SOURCE MATERIAL. Description of the area, climate, and soil is provided in Dahl et al. (1974) and Judd et al. (1977). The flora of South Padre Island catalogued by Lonard et al. (1978) formed the basic list of taxa. Seven additional species have been collected subsequent to publication of that paper and have been included. Designations of topographic zones follow Judd et al. (1977). Much of the information on the distibution of the species found on South Padre Island was obtained from Correll and Johnstons Manual of the Vascular Plants of Texas (1970). Goulds (1975) Grasses of Texas provided information on the distribution of grasses. Ranges of continental taxa were taken from several sources, but McGregor et al.s (1977) Atlas of the Flora of the Great Plains was used extensively. Distributions of Gulf and Atlantic Coast species were primarily obtained from Duncans (1974) review of coastal halophytes. Britton and Millspaughs (1920) treatment of the Bahaman flora was consulted for taxa of Caribbean occurrence. Checklists of Taylor (1950) and Chippendale (1972) were consulted to determine the occurrence of pantropical or subcosmopolitan distributions. Thorne (1972) emphasized the importance of consulting recent monographic revisions and range extension reports when phytogeographic affinities are considered. Therefore, the following monographic treatments were examined for changes in nomenclature and for species ranges: Kral (1971), Sauer (1972), Lewis and Oliver (1974), Gillis and Steam (1974), Graham (1975), Palmer (1975), Rodman (1976), Smith (1976), Hopkins and Blackwell (1977), and Semple and Semple (1977). Nomenclature, in general, follows Correll and Johnston (1970) and Gould (1975). RESULTS AND DISCUSSION. Seven species have been added to the list of vascular species occurring on South Padre Island subsequent to publication of Lonard et al.s (1978) flora. These species are: Atriplex pentandra, Suaeda tampicensis, S. torreyana, Malva parviflora, Orobanche multiflora, Cooperia drummondii, and Dichanthium aristatum. Thus, 216 species of flowering plants are known to occur on South Padre Island. Judd et al. (1977) recognized six topographic zones on South Padre Island: Foreshore (FS), Backshore (BS), Primary dunes (PD), Secondary dunes and vegetated flats (SDVF), Tidal flats (TF), and Washovers (WO). Lonard et al. (1978) added Disturbed sites (DS) and noted the distribution in these zones for each species. One hundred seventeen species comprising 54.2% of the total flora are found in disturbed sites (Appendix). These areas are limited to the southernmost 8 km of the island and are associated with buildings, residences, and roads. Because we are primarily interested in the geographic affinities and the dispersal agents of the naturally occurring flora, the species introduced by man are not considered further. It should be emphasized, however, that man has been the single most important dispersal agent. Our survey indicates that 99 species comprise the naturally occurring flora of South Padre Island. Table 1 provides an inventory of the geographic affini-

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.

The Relationship between Lipid and Reproductive Cycles of a Subtropical Population of Peromyscus leucopus

Lipid indices, basic weights, and reproductive parameters of monthly collections of P. leucopus from the lower Rio Grande Valley of Texas were measured from January through December 1975. a total of 100 adult males and 114 adult females were used in the analyses. Basic weight and percent water varied little among months. There was no significant difference at the .05 probability level in lipid index between the sexes in any month, but mean lipid indices varied significantly among months in both sexes. a peak of reproductive activity occurred in May, June, and July and lipid indices were significantly lower at this time. Starved mice exhibited a mean lipid index of .198, whereas the mean for summer animals was .225, suggesting that mice in summer have largely depleted their metabolizable lipid reserves. Comparisons suggest that the lipid cycle differs in geographically distant populations of P. leucopus . We postulate that changes in food supply, as influenced by rainfall, may regulate the pattern of lipid deposition.

Evaluation of Color-Infrared Photography and Digital Imagery to Map Black Mangrove on the Texas Gulf Coast

Abstract A study was conducted on the south Texas Gulf Coast to evaluate color-infrared (CIR) aerial photography and CIR true digital imagery combined with unsupervised image analysis techniques to distinguish and map black mangrove [Avicennia germinans (L.) L.] populations. Accuracy assessments performed on computer-classified maps of photographic and digital images of the same study site had both producers and users accuracies of 100% for black mangrove. An accuracy assessment performed on a computer-classified map of a digital image only of a second study site had a producers accuracy of 78.6% and a users accuracy of 100%. These results indicate that CIR photography and digital imagery combined with image analysis techniques can be used successfully to distinguish and quantify the extent of black mangrove along the south Texas Gulf Coast.

The biological flora of coastal dunes and wetlands: Spartina patens (W. Aiton) G.H. Muhlenberg.

Abstract Spartina patens (W. Aiton) G.H. Muhlenberg is a New World tropical-, subtropical-, and temperate-zone rhizomatous grass that often is a dominant species in coastal environments. It occurs in habitats ranging from foredunes to saturated soil conditions in high marshes and swales. Herein, we present a review of the extensive literature of this important species. Spartina patens occurs where salinity ranges from 1 to 27 ppt, but it will tolerate salinities up to 40 ppt for brief periods. It tolerates moderate tidal inundation, low nutrient levels, and low to moderate sand coverage. Also known as marshhay cordgrass, it may account for almost all net productivity in high marshes on the Gulf of Mexico coast of Louisiana. High marshes dominated by S. patens are affected by flooding depths associated with global warming and rising sea levels. It is a valuable species for coastal restoration projects for it quickly invades dredged material and storm washover sites. Spartina patens provides cover for wildlife and forage for livestock.