苏南快速城市化地区景观生态优化调控研究

城市化是经济快速发展的必然结果和要求.以苏锡常为代表的快速城市化苏南板块正在导致原有的城乡景观发生快速的变化（优化与恶化并存）.基于城市景观生态调控方法,通过城市景观生态规划（整体共生的理念）、城市景观生态工程（循环再生的理念）和城市景观生态管理（竞争自生的理念）,提出快速城市化过程中城市景观生态优化调控的构想.以苏南地区的常州市武进区为例,从其地理环境背景及景观演化出发,提出可持续发展的景观生态优化的基本原则和目标.将城镇整合成以中心城区斑块为核心的向外辐射的4个城镇景观生态发展斑块,即5大斑块平衡组团的景观格局,协调各行政区域的城市化、工业化发展;典型景观生态片区建设以淹城保护区斑块为核心,以滆湖-太湖斑块和绿色空间基底景观生态建设为主体,依托＂二纵三横＂的生态廊道网络,形成整个武进富有韵律的生态网架,从区域整体上改善、优化城乡景观生态,有效避免景观破碎与退化和生态环境恶化.     

Signaling role of action potential in higher plants

The signaling role of action potential (AP) in higher plants is considered. The principles underlying realization of this role and the significance of AP-induced short-term effector response are discussed. The notion is put forward that the effect of propagating AP on plant cells is similar to nonspecific component of the cell functional response to external stimuli.     

土壤胡敏素研究进展

土壤有机质是土壤的重要组成部分,在土壤肥力和生态环境等方面都具有重要作用.作为土壤有机质主体的腐殖物质的研究,一直受到各国学者的普遍重视.在土壤腐殖物质3组分中,以往的研究主要集中于可溶性的胡敏酸和富里酸,而对不溶性的胡敏素则较少涉及.从分离、结构和作用3个方面,综述了土壤胡敏素的研究现状和最新进展,并对今后的研究方向进行了展望,以促进胡敏素研究的继续深入开展.提出近期的研究重点主要包括:(1)比较不同分离方法获得的土壤胡敏素的差异,以达到方法上的可比性和统一性,同时提出更适宜的分离方法;(2)通过多种分析测试手段的相互补充验证,以获得对土壤胡敏素结构本质更加明确、清晰和深入的认识;(3)加强土壤胡敏素肥力和环境作用的研究,尤其应重视从分子水平上探明其构效关系,为生产实践和应用提供理论依据.     

Impact of spatial disjunction within biophysical classes on plant species composition: implications for conservation planning

The use of surrogates for biodiversity is a practical tool to improve the cost effectiveness of regional conservation planning. However, there is still much uncertainty about the biological representativeness of surrogates. Using a biophysical classification system known as the Mitchell Landscapes, we compare plant species composition in contiguous versus disjunct units of nine Landscape types and hence the ability of this surrogate to capture patterns of plant species composition. We found that plant species homogeneity was higher within a contiguous Landscape than between non‐contiguous units of the same Landscape. Overall, the dissimilarity between non‐contiguous units and their contiguous counterparts was significant (P = 0.004). Biophysical classes with very high dissimilarities between non‐contiguous units of the same region may be of limited utility.     

Temperature and nutrient availability interact to mediate growth and body stoichiometry in a detritivorous stream insect

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Wetlands serve as natural sources for improvement of stream ecosystem health in regions affected by acid deposition

For over 40 years, acid deposition has been recognized as a serious international environmental problem, but efforts to restore acidified streams and biota have had limited success. The need to better understand the effects of different sources of acidity on streams has become more pressing with the recent increases in surface water organic acids, or ‘brownification,’ associated with climate change and decreased inorganic acid deposition. Here, we carried out a large scale multi‐seasonal investigation in the Adirondacks, one of the most acid‐impacted regions in the United States, to assess how acid stream producers respond to local and watershed influences and whether these influences can be used in acidification remediation. We explored the pathways of wetland control on aluminum chemistry and diatom taxonomic and functional composition. We demonstrate that streams with larger watershed wetlands have higher organic content, lower concentrations of acidic anions, and lower ratios of inorganic to organic monomeric aluminum, all beneficial for diatom biodiversity and guilds producing high biomass. Although brownification has been viewed as a form of pollution, our results indicate that it may be a stimulating force for biofilm producers with potentially positive consequences for higher trophic levels. Our research also reveals that the mechanism of watershed control of local stream diatom biodiversity through wetland export of organic matter is universal in running waters, operating not only in hard streams, as previously reported, but also in acid streams. Our findings that the negative impacts of acid deposition on Adirondack stream chemistry and biota can be mitigated by wetlands have important implications for biodiversity conservation and stream ecosystem management. Future acidification research should focus on the potential for wetlands to improve stream ecosystem health in acid‐impacted regions and their direct use in stream restoration, for example, through stream rechanneling or wetland construction in appropriate hydrologic settings.     

Phosphorus availability mediates plasticity in life-history traits and predator–prey interactions in Daphnia

We analysed growth plasticity of two Daphnia pulex clones under low‐phosphorus (LP) and high phosphorus (HP) conditions, in the presence of Chaoborus kairomones to examine how food quality (P‐availability) might impact life‐history responses and vulnerability to predation. Overall, clone 1 grew faster, and was larger at maturity. Under HP, both clones responded to kairomones by increasing growth, age and size at maturity, and decreasing fecundity. Under LP, both clones suffered reduced growth, and fecundity. However, the magnitude of response to kairomones depended on a clone by P‐availability interaction. Chaoborus presented a 1 : 1 clonal mixture under HP or LP, consumed more individuals under LP. Moreover, fewer clone 1 individuals were consumed. Studying the effects of P‐availability on life histories, and predator–prey interactions may help us understand the mechanisms generating and maintaining plasticity, as well as influencing genotypic diversity and microevolutionary processes in natural populations.     

Ecological niche modelling as an exploratory tool for identifying species limits: an example based on Mexican muroid rodents

Niche conservatism theory suggests that recently diverged sister species share the same ecological niche. However, if the ecological niche evolves as part of the speciation process, the ecological pattern could be useful for recognizing cryptic species. In a broad sense systematists agree that the niche characters could be used for species differentiation. However, to date such characters have been ignored. We used the genetic algorithm for rule‐set production for modelling the ecological niche as a means of inferring ecological divergence in allopatric populations of muroid rodents for which taxonomic identity is uncertain. Our results show that niche differentiation is significant in most of the identified phylogroups. The differentiation is likely associated with natural evolutionary units, which can be identified by applying species concepts based on phylogenetic and ecological patterns (e.g. phylogenetic, cohesive, evolutionary). Even so, the role of the niche partition within phylogenetic reconstruction may be a limited one.     

公平规范与自然资源保护——基于进化博弈的理论模型

传统理论认为社区对公共自然资源的管理必然导致"公共地悲剧".但新近研究证明个人行为往往受到社会规范的影响并遵循公平互惠等"非理性"原则,进而指出社群有可能自发实现对公共资源有效的合作保护.基于这一思路,综合运用进化博弈论与行为经济学理论构建数学模型模拟了社区居民参与对自然资源的家庭承包管护的策略演化动态,并分析公平规范在该过程中能够发挥的潜在作用.结果表明在经济补偿相对管护所需劳动成本较为有限的情况下,"理性"的参与者无法长期维持高水平的保护合作;相比之下,如果公平规范对当地居民有较强的约束力,则可以实现更高的保护合作水平,其最终均衡由群体中对公平有较高要求的参与者比例决定.这一结果从理论上预测了利用公平规范推动社区参与自然资源保护合作并提高生态补偿效率的可行性.     

陡坡无土排岩场植被生态修复技术

针对无土陡坡排岩场特殊的立地条件,以城市污泥、粉煤灰等固体废弃物配制的人工土壤进行基质改良的基础上,以坑植式种植刺槐(Robina pseudoacacia)及棉槐(Amor-pha fruticosa),同时在种植坑中撒播牧草以培肥土壤,促进乔木生长固坡。结果表明,在人工土壤Ⅱ(粉煤灰∶城市污泥=1∶1)上种植的刺槐有较好的成活率(70%)和生长势,说明该修复技术在实现以废治废,变废为宝的同时,既解决了矿山废弃地修复中珍贵的土源问题,又改善了矿区生态环境。