生物多样性研究进展

生物多样性是自然资源中的一个重要组成部分。在最近的40年内,生物多样性的研究发展很迅速,有关多样性的测定方法已形成了数十个数学模型和多样性指数。生物多样性的功能也研究得比较多,生物多样性的保护技术也已逐渐系统化,并开始了持续利用和合理开发的研究。     

Remarkable Amphibian Biomass and Abundance in an Isolated Wetland: Implications for Wetland Conservation

Abstract:  Despite the continuing loss of wetland habitats and associated declines in amphibian populations, attempts to translate wetland losses into measurable losses to ecosystems have been lacking. We estimated the potential productivity from the amphibian community that would be compromised by the loss of a single isolated wetland that has been protected from most industrial, agricultural, and urban impacts for the past 54 years. We used a continuous drift fence at Ellenton Bay, a 10-ha freshwater wetland on the Savannah River Site, near Aiken, South Carolina (U.S.A.), to sample all amphibians for 1 year following a prolonged drought. Despite intensive agricultural use of the land surrounding Ellenton Bay prior to 1951, we documented 24 species and remarkably high numbers and biomass of juvenile amphibians (>360,000 individuals; >1,400 kg) produced during one breeding season. Anurans (17 species) were more abundant than salamanders (7 species), comprising 96.4% of individual captures. Most (95.9%) of the amphibian biomass came from 232095 individuals of a single species of anuran (southern leopard frog [Rana sphenocephala ]). Our results revealed the resilience of an amphibian community to natural stressors and historical habitat alteration and the potential magnitude of biomass and energy transfer from isolated wetlands to surrounding terrestrial habitat. We attributed the postdrought success of amphibians to a combination of adult longevity (often >5 years), a reduction in predator abundance, and an abundance of larval food resources. Likewise, the increase of forest cover around Ellenton Bay from <20% in 1951 to >60% in 2001 probably contributed to the long-term persistence of amphibians at this site. Our findings provide an optimistic counterpoint to the issue of the global decline of biological diversity by demonstrating that conservation efforts can mitigate historical habitat degradation.     

宁夏盐池封育区植物特征值及多样性影响

封育措施是一种主要的草场恢复和重建的措施。通过对半干旱沙地老封育、新封育和对照区的比较分析,量化了不同封育措施下植被变化。对3种封育措施群落组成和生物多样性的分析结果表明,封育改变了群落的组成成分并增加了生物多样性,同时对群落植物的生活型、饲用价值分析计算结果则显示,老封育的群落植物逐渐向多年生发展,放牧价值开始降低,而对照区则明显处于一种非平衡的稳定状态。从3种措施植被的盖度、高度、生物量和饲用价值来看,老封育区均低于新封育区和对照区,表明长期封育不利于促进并提高草场的放牧利用价值。     

The Environmental Limits to Globalization

Abstract:  Criticisms of globalization have been largely based on its socioeconomic effects, but the environmental impacts of globalization are equally important. These include acceleration of climate change; drawdown of global stocks of cheap energy; substantial increases in air, water, and soil pollution; decreases in biodiversity, including a massive loss of crop and livestock varieties; depletion of ocean fisheries; and a significant increase in invasions of exotic species, including plant, animal, and human pathogens. Because of negative feedback from these changes, the future of globalization itself is bleak. The environmental and social problems inherent in globalization are completely interrelated—any attempt to treat them as separate entities is unlikely to succeed in easing the transition to a postglobalized world.     

广东丰溪自然保护区昆虫多样性初步研究

通过对广东大埔丰溪自然保护区设置30个样地调查采集昆虫标本，并将所采集的标本进行区系分析和物种多样性分析，结果表明：丰溪自然保护区作为南亚热带向中亚热带过渡地带，其昆虫区系以东洋区成分占绝对优势；昆虫物种多样性指数在1．7491～2．7728之间，阔叶林下昆虫物种多样性指数平均数要高于竹林．     

生态系统生物多样性研究及其保护对策

本文综述了生态系统多样性在生物多样性保护中的意义及５个中心研究问题，即生物群落或生态系统关键种、生物多样性关键地区、生态系统多样性的持续性、受害生态系统的恢复生态学、生态系统多样性保护对策及保护途径。文章还分析和讨论当前国际上有关生态系统多样性保护的对策和实践。     

Catastrophic Decline in Mollusc Diversity in Eastern Tasmania and Its Concurrence with Shellfish Fisheries

Abstract:  We used historical patterns of deposition of mollusc shells to infer changes to inshore benthic assemblages in the southeastern Tasmanian region over the past 120 years. We identified and counted shells in slices embedded within 1m long ²¹⁰Pb-dated sediment cores were collected at 13 sites in water depths of 8–16 m. Declines in mollusc species richness and shell production occurred during the past century at all sites studied, with a mean decline per 5-cm sediment slice from 21 species in 1890 to 7 species in 1990 and in shell abundance from 150 to 30 individuals over the same period. The time course of decline notably corresponded with the history of the scallop dredge fishery, presumably either because scallop dredging caused general declines in populations of mollusc species or because other factors caused a catastrophic regional decline in molluscs that included scallops. As a consequence, the fishery was forced to close. Of major concern is that losses had not previously been recognized but extended throughout the 100-km coastal span of the study. Given that fishing and other anthropogenic impacts, as well as a lack of observational data, are virtually ubiquitous for the coastal zone, major recent losses in mollusc biodiversity may be globally widespread but have gone unnoticed.     

基因污染与生态环境安全

论述了基因污染可能对生态环境安全造成的影响。转基因作物有可能污染天然物种的基因库；有可能破坏传统农作物品种的遗传多样性，加速作物种植品种的单一化及基因资源的流失；使抗除草剂作物的基因向野生或半野生植物漂移的可能性加大，有可能创造出“超级杂草”；带有病毒型转基因作物的基因重组，有可能创造出新的植物病毒，导致新的病害；BT转基因抗虫作物分泌的毒素，在食物链中传递，很难加以控制，对非目标生物造成危害，并最终破坏自然生态系统的平衡。文章还从不同角度分析了基因污染的严重性。     

Recovery of Soil Macrofauna Communities after Forest Clearance in Eastern Amazonia, Brazil

Abstract:  As primary forest is cleared, pastures and secondary forest occupy an increasing space in the Amazonian landscape. We evaluated the effect of forest clearing on a soil macrofauna (invertebrate) community in a smallholder farming system of southeastern Amazonia. We sampled the soil macrofauna in 22 plots of forest, upland rice fields, pastures, and fallows of different ages. In total, we collected 10,728 invertebrates. In cleared plots the species richness per plot of the soil macrofauna fell from 76 to 30 species per plot immediately after forest clearance, and the composition of the new community was different. Ants, termites, and spiders were most affected by the disturbance. In plots deforested several years before, the effect of forest clearance was highly dependent on the type of land use (pasture or fallow). In fallows, the community was similar to the initial state. The species richness per plot in old fallows rose to 66, and the composition was closer to the primary forests than to the other types of land use. On the contrary, in the pastures the species richness per plot remained low at 47. In fallows, all the groups showed a richness close to that in primary forest, whereas in the forest only the richness of earthworms and Coleoptera recovered. Our results show that forest clearing constitutes a major disturbance for the soil macrofauna and that the recovery potential of the soil macrofauna after 6 or 7 years is much higher in fallows than in pastures. Thus, fallows may play a crucial role in the conservation of soil macrofauna.