A TEST OF FOOD PARTITIONING BETWEEN THE AQUATIC LARVAE OF TWO PARAPATRIC SPECIES OF TWO-LINED SALAMANDER (EURYCEA BISLINEATA SPECIES COMPLEX) IN A ZONE OF SYMPATRIC CONTACT

Phylogenetically related species with similar ecologies often partition resources when in sympatry. Food is an important factor in the co-occurrence of sympatric salamanders, and food partitioning occurs in a variety of sympatric, similar species. Several members of the Two-lined Salamander (Eurycea bislineata) species complex are largely parapatric but co-exist within a narrow zone of sympatric contact. Because larvae of these salamanders frequently occur in very high densities, we tested the hypothesis that larvae of the Blue Ridge Salamander (E. wilderae) and the Southern Two-lined Salamander (E. cirrigera) partition food in sympatry in northeastern Georgia. We predicted that the diets of these two species would differ in sympatry and that the respective diet of each species would differ between allopatric and sympatric populations. Both species fed largely on the aquatic larvae of Trichoptera and Diptera, and their diets reflected the available insect fauna of the respective streams. There was no significant difference between the species in sympatry or between allopatric and sympatric populations of either species. Although we found no evidence of food partitioning, we cannot rule out interspecific competition that may manifest itself in some resource other than food

The Influence of Rising Atmospheric CO\u3csub\u3e2\u3c/sub\u3e on Grassland Ecosystems

Increasing atmospheric CO2 concentrations and climatic change will have significant effects on the ecology of grasslands. This paper evaluates results from four CO2 enrichment studies in contrasting grasslands. A Swiss study investigates the effects of elevated CO2 (600 μL L-1 CO2) on perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L), a New Zealand study examines how elevated CO2 (475 μL L-1 CO2) affects a botanically diverse pasture, and studies in the Kansas tallgrass prairie and the Colorado shortgrass steppe investigate the effects of an approximate doubling of CO2 in native grasslands. Productivity in all four grasslands was enhanced at elevated CO2, with the largest relative increases occurring in dry years on the shortgrass steppe (71%) and on the tallgrass prairie (36%). Nitrogen additions, whether from fertilizer or legumes, enhanced the capability of these grasslands to respond to CO2, and legumes were among the most competitive plant types in the Swiss and New Zealand grasslands under elevated CO2. No evidence was found to support the notion that C3 grasses were more competitive under elevated CO2 compared to C4 grasses. The results suggest that CO2 enrichment and global warming will have important impacts on grasslands

Mycorrhizal influences on big bluestem rhizome regrowth and clipping tolerance

Mycorrhizal symbiosis is critical to growth of many warm-season prairie grass seedlings, but its effect on regrowth of rhizomes has not been determined. As forage species, the effect of grazing on the symbiosis is also important. when the impact of mycorrhizae on regrowth of Andropogon gerardii Vit. rhizomes was assessed, A. gerardii rhizomes collected from the field and grown with mycorrhizal inoculum produced larger plants than rhizomes grown in the absence of the symbiont. The effect of the symbiosis on clipping (simulated grazing) tolerance was quantified by growing A. gerardii in steamed or nonsterile prairie soil, with or without mycorrhizal fungus inoculation. Plants were clipped and a portion of the plants harvested at 6, 12, 18, 24, and 30 weeks after planting. As an additional control, Benomyl fungicide was applied to plants to inhibit the symbiosis. Mycorrhizal clipped plants were larger than nonmycorrhizal clipped plants, but the difference diminished with successive clippings. Mycorrhizal root colonization also decreased in response to repeated clipping. Maximum shoot and root biomass of mycorrhizal plants was produced at 12 and 18 weeks, respectiveIy. Fungicide-treated plants did not grow appreciably after the fit clipping. Thus, mycorrhizae improved clipping tolerance, but with repeated intensive clipping, significant changes in root/shoot ratio occurred and eventually mycorrhizal root colonization and growth benefit were lost.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Non-aqueous electrolyte solutions in chemistry and modern technology

In this paper a brief survey is given of the properties of non-aqueous electrolyte solutions and their applications in chemistry and technology without going into the details of theory. Specific solvent-solute interactions and the role of the solvent beyond its function as a homogenous isotropic medium are stressed. Taking into account Parker's statement1) ldquoScientists nowadays are under increasing pressure to consider the relevance of their research, and rightly sordquo we have included examples showing the increasing industrial interest in non-aqueous electrolyte solutions. The concepts and results are arranged in two parts. Part A concerns the fundamentals of thermodynamics, transport processes, spectroscopy and chemical kinetics of non-aqueous solutions and some applications in these fields. Part B describes their use in various technologies such as high-energy batteries, non-emissive electro-optic displays, photoelectrochemical cells, electrodeposition, electrolytic capacitors, electro-organic synthesis, metallurgic processes and others. Four Appendices are added. Appendix A gives a survey on the most important non-aqueous solvents, their physical properties and correlation parameters, and the commonly used abbreviations. Appendices B and C show the mathematical background of the general chemical model. The Symbols and abbreviations of the text are listed and explained in Appendix D