12 research outputs found
Body growth in one montane population of Sceloporus grammicus (Sauria, Phrynosomatidae) in Central MĂ©xico
We conducted an analysis of the body growth pattern of the viviparous lizard Sceloporus grammicus in one of its montane populations in Central MĂ©xico. We calculated 177 individual growth rates for the period comprised between June 1991 and June 1997. Von Bertalanffy growth model provided the best fit to our data in comparison with logistic models. No intersexual differences were found in the growth pattern. The constructed growth curve estimated an age at maturity of 12 and a half months for females and 14 months for males. In spite of marked seasonality in the region, growth rates were not significantly different between seasons. Our results, together with previous studies on the growth ecology of other populations of S. grammicus, suggest that in the volcanic mountains of Central MĂ©xico body growth, and therefore age and size at maturity, are relatively more limited during the whole year in comparison with populations inhabiting northern or lower-altitude localities
Demography of the lizard Sceloporus grammicus: exploring temporal variation in population dynamics
We conducted a 5 year demographic study in one population of the viviparous lizard Sceloporus grammicus Wiegmann, 1828 in central MĂ©xico. The population was structured in three size classes (juveniles, small adults, and asymptotic adults) for which we estimated annual survival and fecundity rates. A population projection matrix was constructed for each annual transition. All of them resulted in finite rates of population growth (?) that, although variable from year to year (from 0.808 to 1.065), were not significantly different than unity, indicating population stability. Elasticity analysis revealed that survival staying in the same size class was the demographic process that made the greatest contribution to ? values in most years. Similarly, the stasis of large adults was the vital rate with the highest relative importance for population persistence. To incorporate the observed yearly variation in long-term population projections, we used a mean matrix, a stochastic simulation, and a resampling procedure. All these resulted in long-term population growth rates that were not significantly different than unity. Our results indicate overall demographic stability for the studied population of S. grammicus
Growth and demography of one population of the lizard Sceloporus mucronatus mucronatus
We report on growth and demography of Sceloporus mucronatus mucronatus, a lizard subspecies endemic to central Mexico. We characterize the life history of this subspecies, provide quantitative information relevant to conservation, and add to the growing literature on the diversity of life histories in the genus Sceloporus. We calculated body growth rates and fitted them to the Von Bertalanffy, the logistic-by-length, and the logistic-by-weight growth models. The Von Bertalanffy model provided the best fit, and we used it to analyze the growth pattern. Growth rates were similar during the 1st year of life in both sexes, but after that point males grew faster and reached maturity earlier (20 months) than females (31 months). We used a population projection matrix to model population dynamics during 2003â2004 and found a positive population growth rate (?= 1.769). However, based on the projected stable size-class vector (w), this population does not appear to have reached stability, and it might be currently experiencing considerable interannual fluctuations. Elasticity values showed that the transition from the juvenile stage to the 1st adult stage was the vital rate that contributes the most to population growth rate, followed by fecundity and stasis of the 1st reproductive category. While total elasticities for demographic processes were similar, elasticities per size class showed the relatively high importance of small adults in comparison to juveniles and large adults. The restriction of this endemic subspecies to central Mexico, where human activities and consequent habitat destruction are increasing, demands further quantitative evaluation and monitoring of populations, even though our results indicate a potential for population growth
Relative importance of reproductive life-history paths in one population of the lizard Sceloporus grammicus
Life cycles of living organisms are composed of distinct sub-cycles that represent alternative life-history paths with differential impact on fitness. We identified three reproductive life-history paths (referred here as loops) in the life cycle of one population of the viviparous lizard Sceloporus grammicus. We evaluated the relative importance of each one of these reproductive paths for the population fitness of these lizards during a 5-year period. The first path corresponded to early reproduction and included survival to maturity and early fecundity. The second path was late reproduction loop and included survival to larger adult sizes with the corresponding fecundity rate. The third was composed of those individuals skipping the small adult stage within a single year, reaching larger sizes early in life with their corresponding larger litters (fast growth loop). To examine the potential effects of environmental factors on the relative contribution of these alternative life-history paths to fitness, we estimated stage-specific survival and growth as functions of annual temperature and rainfall. Using these estimates of vital rates we constructed annual population projection matrices. Then, using demographic elasticities and loop analysis, we calculated the relative contribution of each of the three reproductive paths to the population growth rates. Our results showed that the early reproduction loop is the path with the greatest relative contribution to the population growth rate in most years. However, increases in environmental temperature resulted in higher population growth rates and in greater contribution of the fast growth path to the overall fitness of these lizards
Notes for genera â Ascomycota
Knowledge of the relationships and thus the classification of fungi, has developed rapidly with increasingly widespread use of molecular techniques, over the past 10--15Â years, and continues to accelerate. Several genera have been found to be polyphyletic, and their generic concepts have subsequently been emended. New names have thus been introduced for species which are phylogenetically distinct from the type species of particular genera. The ending of the separate naming of morphs of the same species in 2011, has also caused changes in fungal generic names. In order to facilitate access to all important changes, it was desirable to compile these in a single document. The present article provides a list of generic names of Ascomycota (approximately 6500 accepted names published to the end of 2016), including those which are lichen-forming. Notes and summaries of the changes since the last edition of `Ainsworth Bisby's Dictionary of the Fungi' in 2008 are provided. The notes include the number of accepted species, classification, type species (with location of the type material), culture availability, life-styles, distribution, and selected publications that have appeared since 2008. This work is intended to provide the foundation for updating the ascomycete component of the ``Without prejudice list of generic names of Fungi'' published in 2013, which will be developed into a list of protected generic names. This will be subjected to the XIXth International Botanical Congress in Shenzhen in July 2017 agreeing to a modification in the rules relating to protected lists, and scrutiny by procedures determined by the Nomenclature Committee for Fungi (NCF). The previously invalidly published generic names Barriopsis, Collophora (as Collophorina), Cryomyces, Dematiopleospora, Heterospora (as Heterosporicola), Lithophila, Palmomyces (as Palmaria) and Saxomyces are validated, as are two previously invalid family names, Bartaliniaceae and Wiesneriomycetaceae. Four species of Lalaria, which were invalidly published are transferred to Taphrina and validated as new combinations. Catenomycopsis Tibell Constant. is reduced under Chaenothecopsis Vain., while Dichomera Cooke is reduced under Botryosphaeria Ces. De Not. (Art. 59)