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71.
Hugh DeForest Safford 《Journal of Biogeography》1999,26(4):713-737
Aim This paper presents a basic analysis of the macro- and mesoclimate of the Brazilian campos de altitude, a series of cool–humid, mountaintop grasslands in southeastern Brazil, and compares results with data from other tropical as well as temperate alpine sites. Location Beginning at altitudes of 1800–2000 m, the campos de altitude are found atop the highest summits of the main ranges of the southeastern Brazilian Highlands, between the states of Santa Catarina and Minas Gerais/Espírito Santo. Methods Macro- and mesoclimatic parameters for the campos de altitude are derived from both original data and previously reported results. Parameters include approximate radiation budgets, temperature lapse rates, seasonal and diurnal patterns in temperature, occurrence of frost, elevational gradients in precipitation, and interannual and seasonal patterns in precipitation. Using multivariate techniques and simple numerical contrasts, the climate of the campos de altitude is compared to climates of other tropical as well as temperate alpine sites. Results With respect to patterns of seasonality and the marked influence of polar frontal activity, the macroclimate of the campos de altitude is typically tropical-marginal. However, in reference to actual temperature and precipitation values, the length and profundity of the dry season, average humidities and cloudiness, the climate of the campus de altitude more closely corresponds to that of more inner-tropical systems. These commonalities are best developed with respect to páramo climates of the northern Andes and, especially, Costa Rica. Main conclusions Their very different latitudinal and geographic positions notwith- standing, the campos de altitude and high mountain formations of the N. Andean and Central American Cordillera show clear macroclimatic congruities. In these congruities reside both the environmental basis for strong Andean–southeast Brazilian biogeographic connections, and the context within which evolutionary and ecological parallelisms have developed in the biota of these two widely separate neotropical mountain systems. 相似文献
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Plant and Soil - Quantitative samples of fine roots (d≤3 mm) were extracted from the soil of a 90-year-old beech-birch-maple stand that had been previously treated with lime (1120 kg/ha) or... 相似文献
75.
Fish cell lines: Two new cell lines derived from explants of trunk musculature ofCynoscion arenarius
B. L. Middlebrooks D. L. Stout R. D. Ellender S. Safford 《In vitro cellular & developmental biology. Plant》1981,17(5):427-430
Summary Two cell lines were established from explants of trunk musculature of healthy, males sand seatrout,Cynoscion arenarius. One of the lines, designated CyA-1, has been carried through 150 subcultures during 6 yr. The other, designated CyA-2, has
been carried through 100 subcultures during 2 yr. Both lines grow well in L15 medium adjusted to 0.150M NaCl and supplemented with 10% fetal bovine serum. Optimal growth occurs at temperatures between 24 and 30°C. The species
of origin of both lines was confirmed by a cytotoxic antibody dye exclusion test. The karyotype of CyA-1 has not yet stabilized,
showing a modal chromosome number of 120 at Passage 9, 89 at Passage 63, and 79 at Passage 100. The karyotype of CyA-2 is
rather stable, with a modal chromosome number of 47 at Passage 1 and 49 at Passage 100. Chromosome morphology of CyA-2 is
homogeneous (small, acrocentric), whereas the chromosomes of CyA-1 show considerable size variation (with small chromosomes
possibly formed from fragmentation of original structures). Both lines were found to be free of bacterial or fungal contamination.
Both lines supported replication of lymphocystis virus strains isolated fromBairdiella chrysura (the silver perch) and fromMicropogon undulatus (the Atlantic croaker) but were refractory to 11 other viruses (4 from fish, 1 from amphibians, and 6 from mammals).
This study was supported in part by the National Oceanographic and Atmospheric Administration, Office of Sea Grant No. 04-3-158-58. 相似文献
76.
Hugh DeForest Safford 《Journal of Biogeography》1999,26(4):693-712
Aim The campos de altitude are a series of cool-humid, grass-dominated formations restricted to the highest summits of the southeastern Brazilian Highlands. Relatively little is known of the ecology, biogeography, or developmental history of this archipelago of mountaintop formations. This contribution presents an overview of our present state of knowledge with respect to the past and present physical environment and vegetation of the campos de altitude. The aim is (1) to introduce an international audience to the natural history of these diminutive yet important ecosystems, and (2) to provide the background for a series of forthcoming contributions that will treat the ecology of the campos de altitude and explore physical and biotic relationships between these ‘Brazilian páramos’ and similar formations in the high mountains of equatorial South and Central America. Location Beginning at altitudes of 1800–2000 m, the campos de altitude are found atop the highest summits of the main ranges of the southeastern Brazilian Highlands, between the states of Santa Catarina and Minas Gerais/Espírito Santo. Methods Drawing upon both original data and previously published results, this contribution reviews what we presently know about the physical environment and vegetation of the campos de altitude, in the context of geographic setting, geology, palaeoclimatology and palaeobotany, modern climate, modern vegetation, and conservation. Results and main conclusions Uplift of the southeastern Brazilian ranges to altitudes high enough to support orographic grasslands may have occurred as early as the middle- to late-Tertiary; pollen records show that campos de altitude have been extant on southeastern summits at least since the Late Pleistocene. The present-day climate of the campos de altitude is cool and (per)humid, but patterns of rainfall, temperature, and frost are distinctly seasonal. Although the flora of the campos de altitude is highly diverse and characterized by a high degree of endemism, the campos de altitude maintain strong floristic similarities to equatorial alpine formations of the Andean and Central American Cordillera; these similarities also extend to climate, soils, and vegetation physiognomy. Anthropogenic fires and grazing are widespread in the campos de altitude and probably contribute significantly to the modern structure of vegetation communities. 相似文献