Conserving Biological Diversity through Ecosystem Resilience

Confusion over the term ecological redundancy (Walker 1992) requires that the concept be clarified in order to advance the developing theory that maintaining ecosystem function conserves biological diversity. The species approach to conserving biological diversity assumes that the species in trouble are already identified. The ecosystem approach attempts to deal with the problem of conserving all the species in an ecosystem, including those not yet known. This is best achieved by ensuring that the ecosystem continues to function approximately as it has by maintaining its essential structure. Ecosystem stability (the probability of all species persisting) is enhanced if each important functional group of organisms (important for maintaining function and structure) comprises several ecologically equivalent species, each with different responses to environmental factors. In this sense ecological redundancy is good because it enhances ecosystem resilience, but functionally important groups (guilds, functional types) that have only one or very few species deserve priority conservation attention because their functions could be quickly lost with species extinctions.     

Mitochondrial DNA Variability of the Gray Wolf: Genetic Consequences of Population Decline and Habitat Fragmentation

The gray wolf is a large, highly mobile predator whose original geographic range included most of the Northern Hemisphere. High rates of genetic exchange probably characterized even distantly-separated populations in the past, but recent population declines and habitat fragmentation have isolated previously contiguous populations, especially in the Old World. We examine mitochondrial DNA (mtDNA) variability among twenty-six populations of wolves from throughout their geographic range. We find eighteen mtDNA genotypes in gray wolves, seven of these are derived from hybridization with coyotes, four are confined to the New World, six are confined to the Old World and one is shared by both areas. Genetic differentiation among wolf populations is significant but small in magnitude. In the Old World, most localities have a single unique genotype, whereas in the New World several genotypes occur at most localities and three of the five genotypes are nearly ubiquitous. The pattern of genetic differentiation in the gray wolf contrasts with that of another large, highly vagile canid, the coyote, in which genetic differentiation among populations is not significant even among widely separated localities. We suggest that the difference between these two species reflects the rapid, recent increase in coyote numbers and expansion of their geographic range, and the coincident decline in gray wolf populations. Apparent genetic differences among extant wolf populations may be a recent phenomenon reflecting population declines and habitat fragmentation rather than a long history of genetic isolation.     

城市生态系统承载力研究进展

承载力一词来自生态学,最初应用于对自然生态系统中生物数量的研究。从城市生态学与城市生态系统理论的发展角度介绍了城市生态学中承载力一词含义及其发展过程,并重点介绍了国内外学者对资源承载力、环境承载力及生态承载力的研究与应用。针对城市所具有的明显自然-社会-经济复合生态系统特征,笔者认为应该在城市生态系统承载力研究中强调社会经济系统能力的贡献。     

A Practice-based Approach to Ecosystem Management

Ecosystem management is a rapidly evolving philosophy or paradigm of natural resource management intended to sustain the integrity of ecosystems. The problem is that principles of ecosystem management are unsatisfactory for practical purposes. Three major approaches to the problem are evaluated: (1) clarification of the goals of ecosystem management, (2) construction of a better scientific foundation for management decisions, and (3) comparative appraisal of current practices. The evaluation concludes that neither of the first two approaches is necessary or sufficient for better management decisions because better decisions depend upon the complexities of particular contexts. The third, practice-based approach makes the most of the limited human capacity to cope with the complexities of ecosystem management in order to improve principles of ecosystem management, to inform particular management decisions through improved principles, and to incorporate clearer goals and a better scientific foundation as they become available. The evaluation draws on experience and disciplines beyond conservation biology and natural resource management, including policy sciences.     

生态系统服务研究的问题与展望

生态系统服务的研究是当前资源经济学和生态经济学的研究热点之一。通过分析生态系统服务的概念辨析,认为从生态系统功能的定义过渡到生态系统服务定义的过程中,在关注生态系统整体性的同时忽略了生态系统要素之间的相互作用,导致生态系统服务的评估中可能存在着重复估值或者估值不全面等风险。针对目前的很多生态系统的评估对生态系统的耗损贬值和环境退化所造成的负效益的忽略,以及对人类活动的干扰和气候变化等对生态系统服务产生影响研究不足,提出在今后的研究中应该在深入理解生态系统的复杂生态学机制的基础上,结合数学模型模拟在不确定性下的各种风险损失,加强对生态系统服务的时空动态分析,重视在气候变化、经济发展、环境污染、城市化以及人类活动的过度放牧和过度开垦引起的水土流失、环境退化、荒漠化等土地利用变化的干扰时生态系统服务的变化和反馈,更进一步分析和预测生态系统服务的损益和响应研究;通过长期的试验监测揭示生物多样性和生态系统的关系,测度出土地利用和环境变化对生物多样性的影响和边际效益,及其对生态系统服务的影响的弹性值,实现生态系统服务的精确估值;关注生态系统服务对人类福利的影响,尤其重视贫困地区和生态脆弱区的生态系统服务对减小贫困的研究,建立科学的生态补偿机制,实现可持续发展。     

Prioritizing Conservation Effort through the Use of Biological Soil Crusts as Ecosystem Function Indicators in an Arid Region

Abstract: Conservation prioritization usually focuses on conservation of rare species or biodiversity, rather than ecological processes. This is partially due to a lack of informative indicators of ecosystem function. Biological soil crusts (BSCs) trap and retain soil and water resources in arid ecosystems and function as major carbon and nitrogen fixers; thus, they may be informative indicators of ecosystem function. We created spatial models of multiple indicators of the diversity and function of BSCs (species richness, evenness, functional diversity, functional redundancy, number of rare species, number of habitat specialists, nitrogen and carbon fixation indices, soil stabilization, and surface roughening) for the 800,000‐ha Grand Staircase‐Escalante National Monument (Utah, U.S.A.). We then combined the indicators into a single BSC function map and a single BSC biodiversity map (2 alternative types of conservation value) with an unweighted averaging procedure and a weighted procedure derived from validations performance. We also modeled potential degradation with data from a rangeland assessment survey. To determine which areas on the landscape were the highest conservation priorities, we overlaid the function‐ and diversity‐based conservation‐value layers on the potential degradation layer. Different methods for ascribing conservation‐value and conservation‐priority layers all yielded strikingly similar results (r= 0.89–0.99), which suggests that in this case biodiversity and function can be conserved simultaneously. We believe BSCs can be used as indicators of ecosystem function in concert with other indicators (such as plant‐community properties) and that such information can be used to prioritize conservation effort in drylands.     

生物法脱氮除磷技术及其研究进展

污水脱氮除磷技术在近些年来一直是水处理领域所关注的热点和难点，文章对污水生物法脱氮除磷机理做了简要分析，介绍了几种高效、经济、实用的生物脱氮除磷工艺，并评述了近年来脱氮除磷技术的研究进展。     

The Toxicology of Silica Nanoparticles: A Review

Silica nanoparticles are increasingly used in industrial, cosmetics, and medical applications. Workers in nanosilica production industries, laboratory personnel in drug production industries, patients taking drugs with nanosilica in its formulations, and everyone in society who uses cosmetics are potentially at risk to health effects induced by silica nanoparticles. Like other nanomaterials, nanosilica has unique physical and chemical properties that modify its toxic effects compared to bulk silica or microparticles of silica. Nanosilica toxicology has been studied by various in vitro and in vivo protocols and on humans, studies which are collected and summarized in the present publication. The toxic effects are outlined based on the type of body compartment, viz. cardiovascular, dermal, respiratory, neural, hepatic, genetic, immune, reproductive, and renal system. Further information, especially the experimental protocols and toxicological endpoints, are summarized in tables.