Ground Lizard Research Articles

Rat management for endangered species protection in the U.S. Virgin Islands

Author(s): Witmer, Gary W.; Campbell, Earl W., III; Boyd, Frank | Abstract: Introduced roof rats (Rattus rattus) pose a substantial threat to the fauna and flora of many tropical islands. In the Caribbean, there is concern about rat impacts to several endangered species, including the Atlantic hawksbill sea turtle (Eretmochelys imbricata) and the least tern (Sterna antillarum). The authors surveyed the rat population on Buck Island, Buck Island Reef National Monument, U.S. Virgin Islands in February 1998. Based on three nights of trapping, rats were of low to moderate abundance during the sampling period when compared to results from other Caribbean islands. The impact of rats on native vegetation was evident over the entire island. A rat management program was proposed using anticoagulant rodenticide baits in bait boxes in and around the two picnic areas on the island. Once an appropriate rodenticide registration is obtained, the baiting program can be extended to include the rest of the island. The eventual eradication of rats from Buck Island will not only provide relief for several endangered species nesting on the island, but will set the stage for the reintroduction of the endangered St. Croix ground lizard (Ameiva polops).

EVOLUTION OF THE BISEXUAL SPECIES OF CAUCASIAN ROCK LIZARDS: A PHYLOGENETIC EVALUATION OF ALLOZYME DATA

The phylogeny of 12 species of Caucasian rock lizards and ground lizards, genus Lacerta , subgenus Archaeolacerta , was determined from allozyme data. Three additional species of Lacerta formed the outgroup. Of the 35 loci resolved, 20 were phylogenetically informative. Permutation tail probabilities calculated using Hennig86 and RandomCladistics and g 1 statistics obtained in PAUP revealed significant pattern in the data. Our analysis resolved 12 most parsimonious trees, among which were three well-supported monophyletic groups: 1) ( Lacerta alpina , L. caucasica , L. daghestanica) [the L. caucasica group]; 2) ( L. mixta , L. saxicola , L. raddei-nairensis ) [the L. saxicola group]; and 3) ( L. parvula , L. portschinskii ( L. valentini , L. rudis )) [the L. rudis group]. The second and third groups formed a clade. The ground lizards L. praticola and L. derjugini were resolved as ingroup members, but their placement in the globally most parsimonious trees was ambiguous. A preferred tree was chosen by alternately pruning L. praticola and L. derjugini from the tree. In doing so, L. praticola was resolved as the sister taxon of the L. caucasica group, and L. derjugini was resolved as the sister taxon of the clade containing the L. saxicola and L. rudis groups. Our results are somewhat congruent with the morphology-based phylogeny of Darevsky (1967).

Body Size and Growth in Two Populations of the Puerto Rican Ground Lizard (Teiidae)

Growth rate and adult body size of the Puerto Rican ground lizard (Ameiva exsul) are compared for two populations from Mayaguez, Puerto Rico. The population with apparently greater food supplies and less predation shows higher absolute growth rates and larger asymptotic sizes. Within populations, males grow faster than females and reach larger asymptotic sizes. For large animals tail autotomy is significantly more frequent in males than in females.

Time course of laboratory acclimation in the ground lizard,Sitana ponticeriana and the garden lizard,Calotes nemoricola

Time course of laboratory acclimation to cold (20° C) and warm (35° C) temperatures is followed. It is found that the rate as well as degree of thermal acclimation of the rate of oxygen consumption both in the ground lizard,Sitana ponticeriana, and the garden lizard,Calotes nemoricola were dependent on the season and temperature gradient. It was found that acclimation to cold and warm temperatures does not occur in the laboratory.

Structure et dynamique d’un peuplement de Lézards : les Scincides de la savane de Lamto (Côte-d'Ivoire)

Population densities of terrestrial lizards were estimated monthly, for five consecutive years, in the Lamto savanna (Ivory Coast), by collecting all individuals within 900 m2 quadrats. Although their breeding cycles were different, the three most numerous species Mabuya buettneri, M. maculilabris and Panaspis nimbaensis were more abundant during the wet season. These skinks require six months to reach a mature size ; their daily rate of growth is about 0.2 to 0.3 mm. The average reproductive potential of females of Mabuya buettneri, M. maculilabris and Panaspis nimbaensis were determined by counting yolked ovarian follicles and eggs in oviducts, and by estimating clutch size. The average annual egg production was 13.4, 30.4 and 12.8 eggs in the above three species, and the number of clutches 1.5, 5.5 and 5.0 per female per year. Mortality of eggs and hatchings is high and survivorship to maturity is low : 18.2 %, 8,5 % and 25.1 % of eggs laid respectively by Mabuya buettneri, M. maculilabris and Panaspis nimbaensis. From sexual maturity onwards, the death rate for females is lower than that of males in all species, but is fairly high for both sexes. The longest average life expectancy is about 9.0 months for females of Mabuya maculilabris, and the shortest 1.3 months for males of M. buettneri. Although they are opportunistic feeders, these sympatric lizards do not compete for the same preys because their activity patterns, their behaviours and their sizes are fairly different. The annual food consumption of the ground lizard community in Lamto savanna is about 3 kg/ha (live weight) and its average net production, calculated from life tables, is about 300 g/ha/year. Ecological efficiency of the Mabuya species is 10 %.

Toward a Quantification of the Ecological Niche

The suggestion is made that a finite number of broad ecological niches exist in any biome type and that these niches may be defined by comparisons of convergent forms from different continents. Major categories of amphibian and reptilian faunas of southeastern Texas and southeastern Brazil are compared, and frogs of the two areas are morphologically compared, species to species. Biological points of comparison should include ecology and physiol- ogy as well as morphology. Such a comparison is attempted for the cricket frog niche with seven species of cricket frogs from five continents. Although the attempt illustrates the type of comparison needed, it is concluded that past natural history studies do not yield the detailed type of information needed. It is hoped, though, that such information will come from future studies. Those of us who have had the opportunity to collect animals on several continents have been impressed with the number of convergent forms which occur on those continents in comparison with our home continents or each other. For example, I have compared the North American cricket frogs (Acris) and ground lizards (Lygosoma) with South American cricket frogs and ground lizards, Pseudo paludicola and Pantodactylus (Milstead, 1961 a, b); Minton (1962) has com- pared a number of Pakistani forms with North American forms!; Pianka and Pianka (1970) and Pianka (1971) have compared two American and Australian lizards, and Sage (in press) has compared a

A Method of Counting Some Diurnal Ground Lizards of the Genera Holbrookia and Cnemidophorus with Results from the Big Bend National Park

The Big Bend region lies in a great U-shaped bend in the course of the Rio Grande. The Big Bend National Park, at the southern- most tip of the Big Bend region and bordered on two sides by the Rio Grande, is included wholly within the Big Bend Biotic District of the Chihuahuan Biotic Province. The climate ranges from arid to semiarid, and great variations of temperature are recorded within relatively short distances. The total annual rainfall is less than 10 inches at lower elevations but approaches or may even exceed 20 inches in the mountains. Most occurs during late summer and early fall. Quantitative studies on the herpetofauna were restricted to the diurnal ground lizards, Holbrookia texana, Cnemidophorus tigris, and C. sacki, on the northern slope of the Chisos Mountains, the highest range in the park. Trapping of lizards was carried on, and observations were made on marked individuals during the summer of 1956. A quad- rat method was developed whereby all lizards are counted within a plot of known area for a specific number of days. These daily counts are averaged to arrive at an index number recorded as lizards per acre. Six quadrats, placed along a transect at elevations of approximately 2,800, 3,100, 3,400, 4,200, 4,650, and 5,250 feet, were operated for two consecutive years. Lizard numbers and vegetation density were recorded and compared from elevation to elevation and from year to year. Only one quadrat (4,200 feet) varied significantly and showed an increase in lizard numbers from the first year to the second. A highly significant dif- ference correlated with elevation was present. The greatest numbers of lizards were recorded at the 4,200-foot level, the least at the 2,800- and the 5,250-foot levels. The density of grasses and forbs was lowest at the 2,800-foot level and highest at 5,250 feet. No change in ratio between the different species of lizards occurring together was apparent during the years of operation.

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The enhancing effects of starch on the jelly strength of kamabokos made from lizard fish producing strong jelly and those of shark affording relatively weak one, have been compared. The jelly strength of non-starch kamaboko made from the latter was shifted by addition of water, but that of the former scarecely affected. When various amounts of starch were added to their ground muscles, the jelly strength of the products from lizard fish containing a small amount of water increased slightly with increasing starch, but in further addition of water rather decreased with increasing starch. It is probable that, although the strength of the products having a large amount of starch and a small amount of water was apparently intensive in strength owing to the hardness of starch paste, when a large amount of water was added, the own strength of fish muscle itself in place of starch paste should be shown. Lizard fish muscle having the higher jelly strength, therefore, seems to be decreased in its proper strength by the interference of starch paste. On the contrary, in the shark kamaboko which jelly strength largely depend upon the stiffness of starch paste, its strength was intensified with increasing addition of starch and decreased with increasing water. These facts seem to be attributable to the different content of soluble proteins in their fishes; lizard fish contains much soluble proteins and shark a less amount of them. Since ground lizard fish muscle may increase in amount of soluble proteins with increasing water, its strength would not be influenced so much by addition of starch and water, while in kamaboko from shark which may decrease in the concentration of soluble proteins in accordance with addition of water, its strength would be decreased and be influenced by starch paste with increasing water.

The Effect of Soil Types on the Helminths Parasitic in the Ground Lizard, Leiolopisma Laterale (Say)

The Effect of Soil Types on the Helminths Parasitic in the Ground Lizard, Leiolopisma Laterale (Say)

The Mechanism of the Throat-Fan in a Ground Lizard, Sitana Ponticeriana CUV.

The Mechanism of the Throat-Fan in a Ground Lizard, Sitana Ponticeriana CUV.