绿色基础设施的生态及社会功能研究进展

随着城市化进程的加快,城市硬化地表不断挤占透水表面,使得绿色基础设施规模不断下降、破碎化程度逐渐加大,严重影响了绿色基础设施服务功能的有效发挥。绿色基础设施的发展经历了早期萌芽、初步形成和快速发展三个阶段,主要在宏观尺度研究区域生态安全,中观尺度促进城市可持续发展,微观尺度解决社区生态环境问题。目前绿色基础设施的研究内容集中在其生态功能和社会功能两个方面,主要关注调蓄降雨径流、消减非点源污染、调节区域微气候、居民健康与福祉和空间布局公平性。而供需结构的合理配置也是决定绿色基础设施服务水平的关键因素。未来的研究应加强与相关学科的交叉融合,完善绿色基础设施功能的测度与评估方法,将绿色基础设施建设与实际规划相结合,以期为区域可持续发展和国家生态文明建设提供支撑与保障。     

鸡粪有机肥对设施菜地土壤重金属和微生物群落结构的影响

通过田间试验,研究在设施菜地上施用不同剂量的鸡粪有机肥对土壤-植物系统中重金属的累积、重金属有效性和土壤微生物群落结构的影响,进一步探讨土壤微生物群落结构与土壤重金属之间的相关关系。结果表明,与对照相比,施用有机肥可提高小白菜地上部生物量,其中施肥量为60 t/hm²时值最大,增幅为59.92%;小白菜地上部Cd、Cr、Cu、Zn和As含量均大幅增加,但Pb含量无明显变化。土壤重金属Cd、Cr、Cu、Zn和As的全量均随鸡粪有机肥施加量的增加而增大,最高增幅分别为21.30%、21.58%、17.40%、19.40%和17.43%,出现明显的累积现象;施用有机肥均增加了土壤Cd、Cr、Cu、Zn和As的有效态含量,而Pb的全量和有效态含量无显著变化;除重金属Pb外,不同重金属元素全量与有效态含量均显著正相关,其中元素Zn的全量与有效态含量相关性最强。磷脂脂肪酸（PLFA）分析结果表明,土壤中含量较高的PLFA为16：0、18：1ω7c、10Me16：0和18：1ω9c,土壤微生物总PLFA和各类群PLFA含量均呈现M0.5 > M1 > CK > M2 > M4;相关性分析结果表明,土壤Cu、As全量和Cd、Cr、Cu、As有效态含量与微生物总PLFA和各类群PLFA含量均呈现显著负相关关系,其中有效态Cr和Cu含量对微生物群落结构的影响最为显著。     

地下水位对黄河三角洲柽柳根系生长的影响

为揭示黄河三角洲柽柳根系生长特征对地下水位的响应规律,明确柽柳生长适宜的地下水位,在咸水矿化度（6 g/L）下,模拟设置0、0.3、0.6、0.9、1.2、1.5、1.8 m共7个地下水位。测定分析栽植柽柳土柱的水盐参数与根系生长指标。结果表明：在咸水矿化度下,地下水位可显著影响土壤水盐变化,从而影响柽柳根系的生长。随地下水位的降低,土壤含水量、含盐量和土壤溶液绝对浓度显著降低。在高水位（≤0.6 m）下,柽柳根系生长受水盐胁迫影响显著,柽柳根长、根径、侧根数、总生物量、侧根生物量、根系连接长度均较低,拓扑结构呈叉状分支;中水位（0.9 m）时,土壤水盐条件适宜,柽柳侧根数、根径、二级侧根和毛细根生物量达到最大值,拓扑结构由叉状分支向鱼尾形分支过渡;低水位（≥1.2 m）下,土壤水盐含量低,柽柳根系总生物量、主根生物量、一级侧根生物量和根系平均连接长度在1.2 m水位达到最大值后降低,拓扑结构呈鱼尾形分支。柽柳根系生长与地下水位密切相关,柽柳通过改变根系生长和调整构型来适应不同土壤水盐和地下水位条件。高水位（≤0.6 m）下柽柳以降低根系生长深度,增加分叉,调配各组织器官的生物量来适应水盐胁迫;中水位0.9 m下土壤水盐条件最适宜柽柳生长;低水位（≥1.2 m）下柽柳主要受土壤干旱胁迫而使根系向下生长,增加根系连接长度,以此扩大资源获取效率。柽柳根系生长及根系构型对咸水矿化度下不同地下水位表现出较强的适应性和可塑性。     

X-linked meiotic drive can boost population size and persistence

X-linked meiotic drivers cause X-bearing sperm to be produced in excess by male carriers, leading to female-biased sex ratios. Here, we find general conditions for the spread and fixation of X-linked alleles. Our conditions show that the spread of X-linked alleles depends on sex-specific selection and transmission rather than the time spent in each sex. Applying this logic to meiotic drive, we show that polymorphism is heavily dependent on sperm competition induced both by female and male mating behavior and the degree of compensation to gamete loss in the ejaculate size of drive males. We extend these evolutionary models to investigate the demographic consequences of biased sex ratios. Our results suggest driving X-alleles that invade and reach polymorphism (or fix and do not bias segregation excessively) will boost population size and persistence time by increasing population productivity, demonstrating the potential for selfish genetic elements to move sex ratios closer to the population-level optimum. However, when the spread of drive causes strong sex-ratio bias, it can lead to populations with so few males that females remain unmated, cannot produce offspring, and go extinct. This outcome is exacerbated when the male mating rate is low. We suggest that researchers should consider the potential for ecologically beneficial side effects of selfish genetic elements, especially in light of proposals to use meiotic drive for biological control.     

基于MSPA和MCR模型的秦岭(陕西段)山地生态网络构建

快速的城市化发展破坏了生境斑块的连通性,而在应对此环境变化中,从斑块层构建区域生态网络的研究不足。本研究以秦岭(陕西段)为对象,采用形态学空间格局分析(MSPA)辨别生态源地,利用最小阻力模型(MCR)提取潜在生态廊道,构建秦岭生态网络;基于重力模型对生态网络内部斑块的重要性进行分级,并分析了网络的结构特征及景观构成。结果表明: 秦岭(陕西段)生态网络由10个生态源地、45条潜在生态廊道和38个脚踏石构成,生态源地总面积29686.15 km²;网络闭合度(0.11)、线点率(1.18)、网络连接度(0.42)、成本比(0.99)综合表明,网络结构中潜在生态廊道和生态节点的连通性较好,而源地间的连通程度低,构建网络的成本较高;重要生态廊道主要由林地、草地、耕地等景观类型构成,其中,林地面积最大,为571.00 km²,约占廊道总面积的89.2%,景观结构良好;在生态网络中应加强保护生态源地,优先建立并保护重要生态廊道和生态节点。研究结果可为秦岭生态环境保护与高质量发展提供科学的参考和依据。     

The effect of temperature changes and K supply on the reproduction and growth of Bolboschoenus planiculmis

温度变化和钾添加对扁秆藨草生长及繁殖的影响 人类活动导致的气候变暖和农业面源污染已被认为是影响湿地植物生长和繁殖的重要因素。为了预 测和缓解这些人类活动的影响,研究沼泽植物如何响应这些环境变化具有重要意义。本研究选取在欧亚 大陆广泛分布的莎草科球茎植物扁秆藨草(Bolboschoenus planiculmis)为研究对象,考察气温变化(恒温： 15、20、25 °C及交替温度：20/10和30/15 °C)和钾添加(0、1、3、9 和18 mmol/L)对其生长和繁殖性状 的影响。研究结果表明,高的恒温(20、25 °C)比高的交替温度(30/15 °C)更有利于扁秆藨草球茎的形成, 而地上生物量和株高一般在较高温度下(30/15、25 °C)达到最大值。扁秆藨草的繁殖和生长性状均与施钾量 呈驼峰型关系,最适施钾量在1–3 mmol/L K。高恒温效应和最适钾浓度的交互作用对繁殖性状的促进作 用最大,但是,较高的温度(30/15和25 °C)和0–9 mmol/L的钾浓度只促进了生长性状的生长。综上所述, 扁秆藨草的种群优势度可能受益于全球变暖和额外的钾添加。     

不同管理模式对茶树碳氮磷含量及其生态化学计量比的影响

植物不同器官的碳(C)、氮(N)、磷(P)含量及其生态化学计量特征能够反映植物内部的养分分配与平衡关系。该研究以福建安溪3种不同管理模式的铁观音茶园为研究对象, 设置了常规管理模式下的茶园(M1)、间作套种模式下的茶园(M2)和现代技术管理模式下的茶园(M3) 3种样地, 分析茶树根、茎、叶器官的C、N、P含量及其化学计量学特征, 养分的变异特征与异速生长关系。结果表明: M2和M3管理模式下茶树根、茎、叶N、P含量均显著高于M1管理模式, C含量差异不明显; 茶树根、茎、叶C:N、C:P、N:P均表现为M1 > M2 > M3。茶树不同器官C、N、P含量差异较大, 根据变异来源分析, 管理模式因素对C、N、P含量变异的影响均达到显著水平。根茎叶N-P的异速生长关系表明茶树不同器官的养分需求存在相似性; 土壤pH和容重是影响C:N、C:P、N:P的重要因素, 而土壤含水量和盐度对茶树根和叶C含量的影响较大。总体来讲, 间作套种以及现代化滴灌、水肥等管理模式可以改善茶树对养分的吸收效率, 对解决土壤养分不均衡问题具有正面效应。     

Metabolic dynamics across prolonged diapause development in larvae of the sawfly,Cephalcia chuxiongica (Hymenoptera: Pamphiliidae)

Nutrient metabolism is crucial for the survival of insects through the diapause. However, little is known about the metabolic mechanism of prolonged diapause. The sawfly, Cephalcia chuxiongica (Hymenoptera: Pamphiliidae), is a notorious defoliator of pine trees in southwest China. One of the distinguishing biological characteristics of this pest is the prolonged diapause of about 1.5 years. In this study, the body lipid, carbohydrate (total body sugar, glycogen, trehalose, and glucose), protein, and glycerol contents were measured in diapausing larvae of C. chuxiongica. The results showed that the changes of biochemical composition in C. chuxiongica are associated with the diapause initiation, maintenance, and termination phases. During the initiation phase, trehalose, glucose, and glycerol increased significantly, but glycogen decreased sharply. In general, the lipid, carbohydrate, and glycerol levels decreased gradually across the maintenance phase. At termination phase, the contents of glycogen and lipid persistently decreased, while an increase of trehalose, glucose, and glycerol contents were detected. The protein level was significantly higher at maintenance phase than at initiation and termination phases. It was also found that elevation of trehalose, glucose, and glycerol contents occurred in winter. These implies that the metabolites with altered levels in diapausing larvae of C. chuxiongica are responsible for maintaining a prolonged development and overwintering.     

Adaptive signaling behavior in stomatopods under varying light conditions

Stomatopod crustaceans (mantis shrimp) are aggressive benthic marine predators with extraordinary color vision. When communicating with conspecifics, many stomatopods display conspicuously colored body areas, often in combination with other types of signals such as motion and chemical cues. Some species occupy wide depth ranges (>30 m), where changing light conditions can influence color perception. To test the potential effects of differing ambient lights on signaling behavior, stomatopods (Gonodactylus smithii) interacted with conspecifics in aquaria, under full-spectrum, high intensity light or light restricted in either spectrum or intensity. During intrasexual and intersexual trials in full-spectrum, high intensity light, animals performed more aggressive acts using colored body parts (meral spread, lunge, strike). Stomatopods used significantly more antennular flicking, and performed aggressive acts at reduced distances under restricted light conditions. To compare the use of antennules in visual and chemical communication, additional experiments showed more antennular flicking in response to chemical stimuli from food or conspecifics compared to seawater controls. This response ceased immediately after ablation of antennular chemoreceptors but returned to pre-treatment levels after 5 days of recovery. These findings suggest that stomatopods can vary their use of signals during conspecific interactions under different photic conditions. These inducible, plastic behavioral responses can potentially improve signal transfer in varying light environments.     

Introduction: International conference on forest ecosystems: Ecology,conservation and sustainable management

Abstract

A pollen diagram from a small lake, Kutulahdenlampi, in northern Finland is interpreted in terms of the development of forest vegetation during the Holocene. The abundance of each of the forest taxa is considered independently by means of pollen accumulation rates (PARs), using as the reference material, long term average pollen deposition values monitored by a network of pollen traps. Particular attention is paid to the arrival of spruce and to the species in the original forests that this newcomer replaces. A model of pollen dispersal and deposition developed by Sugita is used to estimate the area around the lake that the pollen assemblage is most clearly reflecting. This relevant source area of pollen (RSAP), for the present day situations is c. 1,500 m. Pollen loadings calculated for a simulated landscape that mimics (i) that of the present day and (ii) for the situation at 8,000 BP (as deduced from the PARs) are compared with the pollen assemblages from the diagram at those points in time, and are seen to be compatible. The advantages of combining PAR and modelling to look at the spatial scale of vegetation reconstructions are discussed.