挠力河流域河流生境质量评价

选择挠力河流域6个河段21个样点进行河流生境质量调查和评价。采用包括河水、河道和人类干扰等3大项目共11项评价指标,涵盖河流水量、水质和速度与深度组合,河道形状、结构、侵蚀程度和植被状况,河岸人类活动、周围土地利用以及水工设施等河流生境质量评价指标系统,进行河流生境质量评价。结果显示,全流域47.6%的样点河流生境质量处于优等或良好等级,33.3%的样点为一般等级,约19.1%的样点为较差等级,没有最差等级的样点。研究表明,挠力河流域河流生境质量整体状况良好,个别样点生境质量较差;河流生境质量受到周围土地利用的重要影响;河流生境质量与河流水质及河流生物完整性密切相关。有关河流生境评价的指标与标准以及参照系等研究有待深入。     

城镇化背景下河流生境评价——以深圳市为例

城镇化背景下，河流生态系统退化趋势明显，有效评价河流生境状况是修复和保护河流生态系统健康的重要基础。深圳市作为全国经济发展的窗口城市，河流生境的调查研究十分匮乏。因此，为阐明深圳市不同城镇化程度的流域河流生境的差异与主要影响因素，对深圳市两个代表性流域的河流生境展开了研究。针对深圳市河流的生境特点，于2019年丰水期（8月）和枯水期（11月）对城镇化程度较高的深圳河流域的13个样点和城镇化程度较低的坪山河流域12个样点河段的生境状况进行定量调查与评价。采用综合评价法，从河床、河道和河岸带3个方面选取10个生境指标，构建深圳市河流生境评价指标体系和评价方法。结果表明：深圳河流域河流生境质量总体较差，生境评价等级为"良"、"中"、"差"的样点河段分别占7.7%、38.5%、53.8%；坪山河流域河流生境质量总体较好，生境评价等级为"优"、"良"、"中"、"差"的样点河段分别占8.3%、41.7%、41.7%、8.3%。方差分析结果表明两次调查河流生境状况无显著性差异，短时间跨度内河流生境状况变化较小；两个流域河流生境状况差异显著，城镇化程度较低的坪山河流域河流生境质量显著好于城镇化程度较高的深圳河流域。河流生境评估指标主成分分析结果表明人类活动强度、河岸稳定性、河道变化、底质、河岸土地利用及植被多样性是影响深圳市河流生境变化的主要因子。本文对河床、河道、河岸带3个方面分别提出针对性的修复建议，对深圳市河流的生境修复和保护具有重要的指导作用。     

基于主成分分析和熵权法的河流生境质量评价方法——以清河为例

河流生境是维持河流生态完整性, 维护河流健康的一个重要因素, 为更科学准确的对河流生境质量进行评价,以辽宁省清河为研究区域, 分别采用熵权法和主成分分析赋权法确定权重, 构建河流生境质量评价指数(RHI), 以选择一种合理赋权方法。结果显示, 熵权法河流生境质量评价结果显示清河流域生境质量较好的河段3 个, 生境质量一般的河段6 个, 没有生境质量为好和差的河段。主成分分析赋权法评价结果显示生境质量为好的河段2 个, 生境质量较好的河段1 个, 生境质量一般的河段2 个, 生境质量为差的河段4 个。比照清河生境实际情况, 主成分分析赋权法与实际情况相贴切并对指标进行优选, 避免各指标重复赋权, 更全面准确地反映生境质量的高低。     

三峡库区河流生境质量评价

三峡水库建成蓄水后,库区流水生境的大幅度减少及垂直落差最高可达30 m的消落带的形成,使库区支流生境发生了剧烈变化,因此对库区河流生境质量评价十分必要。基于水文情势、河流形态和河岸带生境3个方面18个指标的河流生境评价指标体系,对三峡库区36条重要支流254个样点河段进行河流生境质量评价。结果表明,4.72%的样点河流生境质量处于优等,30.31%为良好等级,49.61%为一般等级,15.35%为较差等级,没有最差等级的样点。对于表征河流生境状况的水文情势、河流形态和河岸带生境3个类别,254个河段总体上河岸带生境状况最好,其次为水文情势,河流形态最差。从总体上来看,三峡库区支流生境质量是自然环境和人类活动相互作用的结果,其中河岸带植被状况、消落带宽度、人为干扰、河床底质状况、水文情势自然性等为主要的驱动因子。     

三峡库区河流生境质量评价

三峡水库建成蓄水后,库区流水生境的大幅度减少及垂直落差最高可达30 m的消落带的形成,使库区支流生境发生了剧烈变化,因此对库区河流生境质量评价十分必要。基于水文情势、河流形态和河岸带生境3个方面18个指标的河流生境评价指标体系,对三峡库区36条重要支流254个样点河段进行河流生境质量评价。结果表明,4.72%的样点河流生境质量处于优等,30.31%为良好等级,49.61%为一般等级,15.35%为较差等级,没有最差等级的样点。对于表征河流生境状况的水文情势、河流形态和河岸带生境3个类别,254个河段总体上河岸带生境状况最好,其次为水文情势,河流形态最差。从总体上来看,三峡库区支流生境质量是自然环境和人类活动相互作用的结果,其中河岸带植被状况、消落带宽度、人为干扰、河床底质状况、水文情势自然性等为主要的驱动因子。     

基于河段尺度的太湖流域城市河流生境评价

快速城市化背景下,太湖流域城市河流水环境与生态功能退化问题日益突出,系统开展城市河流生境评价尤为重要。本研究参考和修正了英国城市河流调查评价体系,基于太湖流域城市河流特点,构建了太湖流域城市河段生境质量指数(SHQI)评价体系,分析太湖流域城市河流生境现状及空间差异。结果表明: 50 个河段的SHQI值介于8～21,3个河段的SHQI值为好,6个为较好,27个为一般,9个为较差,5个为差。太湖流域城市河流生境中植被指数情况较好,物理生境、材质指数情况较差。生境总体状况在空间上表现为镇江>湖州>杭州>嘉兴>苏州>无锡>常州,各城市的物理生境、材质指数与污染指数存在显著差异。干流河段与支流河段的SHQI值无显著差异,但干流河段与支流河段的材质指数和污染指数差异显著。本研究构建的评价体系较好地反映了太湖流域城市河流生境现状,可为城市河流生态修复工作提供参考。     

两类水质综合评价方法的特点及其在河流水环境管理中的作用

河流水质恶化已成为严峻的环境问题,针对河流开展水质综合评价对河流水环境管理具有重要意义。依据不同的评价目标,选择合理的综合评价的评估标准成为河流水质评价中重要的问题之一。通过基于期望值和阈值的水质健康综合评估法(ETI)和水质质量指数(WQI)两种水质综合评价方法对"引滦入津"工程重要水源地伊逊河水质进行评价,结果显示:1)伊逊河水质ETI评估结果为良好等级,WQI评估结果为一般等级;2)伊逊河采样点水质在ETI评价中分布于4个等级,WQI仅分布于2个等级;3)伊逊河自上游至下游水质显著降低,特别是ETI评估中由优秀等级转变为差等级;4)ETI和WQI评估结果显示极显著相关性(R=0.951,P0.01);5)通过逐步多元回归,ETI评估结果的主导因子是DO、EC、SS、BOD_5和TP(P0.05),WQI评估结果的主导因子是DO、SS、BOD_5、TP、TN和NH_3-N(P0.05)。进一步分析表明伊逊河水质恶化与其流域内土地利用情况密切相关。在河流水环境管理中,ETI作为一种水质相对值评估方法,能更好体现流域内水质差异的区分度,便于管理者迅速定位流域内亟需治理的河流或河段,同时能够根据河流自身特征制定管理目标,可作为河流管理绩效评估的有效手段;而WQI作为一种水质绝对值评估方法,更适用于河流水质时间变化评估,对河流经长期治理后的管理效果评价起到重要作用。     

太湖流域宜兴片河流生境质量评价

建立包含河道生境、河岸生境和滨岸带生境3方面共10项的河流生境质量评价指标体系,对太湖流域宜兴片42个样点进行生境评价及空间差异比较,分析不同土地利用类型下河流生境各参数的差异性,探讨河流生境质量指数与富营养化综合指数的相关关系。结果表明:河流生境质量指数分值介于29～79,31.0%样点生境质量处于较差和很差等级,57.1%样点为一般等级,表明整体上生境退化明显;南部丘陵山区河流的生境质量状况好于广大的平原河网区;不同土地利用类型下河流生境质量差异显著,林地区域的生境质量明显好于耕地和建设用地;河流生境质量指数与富营养化综合指数显著负相关,说明水质状况对河流生境质量具有较大贡献。     

拉萨河河流健康评价指标体系构建及应用

为全面反映拉萨河干流生态环境现状,基于拉萨河特征和国内外研究构建了包含水文、水质、生物、生境、服务功能5个要素12个指标的河流健康评价指标体系,提出了赋值标准,并在拉萨干流进行了应用。评价所用数据来自资料收集、文献调研、现场监测和调查。评价结果显示拉萨河干流整体处于较为健康状态,且上游健康状况优于中下游。上游河段枯水期水质达到I类水功能区水质目标,丰水期氨氮含量未达到I类水功能区水质目标,总达标率为50%,赋50分,其余指标赋值大于75分;中游河段受水电站运行和灌溉引水影响,流量过程变异程度、河流连通阻隔状况、大型底栖无脊椎动物科级耐污指数赋值较低,分别为0分、25分和45分,生态基流保障度、外来鱼类入侵率、河道稳定性指标较上游变差,赋值在50—75分之间,其余指标赋值大于75分;下游河段流量过程变异程度、外来鱼类入侵情况赋值为0分,河流连通阻隔状况与中游相同为25分,大型底栖无脊椎动物科级耐污指数赋45分,河道稳定性赋68分,其余指标赋值大于75分。从河流健康角度分析,未来拉萨河流域管理应重点关注上游湿地面源问题、中下游水利水电工程的综合效应、人类聚集区鱼类入侵等问题。     

蒲河水质空间异质性特征及其对流域土地利用方式的响应

河流水质空间变化特征是流域生态系统健康评价的关键指标,是地形、地貌、气候、水文等自然环境因素及综合反映人类活动强度的土地利用方式对流域生态环境的复合作用,研究河流水质空间异质性特征及其对流域土地利用方式的响应关系对流域生态管理具有十分重要的指导意义,然而水质空间异质性特征及其对土地利用方式的响应机制研究仍不清楚。本文以辽河流域支流蒲河子流域为研究对象,利用GIS技术和地统计学方法,分析蒲河流域水质指标TN、TP、NH4+-N、CODcr、pH、DO和TDS空间变异特征,探讨流域不同土地利用方式对水质空间变化的影响。结果表明:蒲河流域水质指标NH4+-N、DO和TDS受结构性因素影响显著,表现出较强空间变异性;TP、CODcr和pH的空间异质性较弱,主要由随机性因素引起;TN受到结构性因素和随机性因素共同作用,表现出较弱空间变异特征;TN和NH4+-N含量与林地所占比例呈显著负相关,与耕地和建设用地所占比例呈显著正相关;pH和DO与水域面积和未利用地所占比例呈负相关;表明蒲河流域TN和NH4+-N空间异质性的主导因素为林地、耕地和建设用地等土地利用类型,pH和DO空间异质性的主导因素为水域和未利用地土地利用类型,该研究可为流域水环境管理提供数据支持。     

Obesity and sexual quality of life

Objectives : Reduced sexual quality of life is a frequently reported yet rarely studied consequence of obesity. The objectives of this study were to 1) examine the prevalence of sexual quality‐of‐life difficulties in obese individuals and 2) investigate the association between sexual quality of life and BMI class, sex, and obesity treatment—seeking status. Research Methods and Procedures : Subjects consisted of 1) 500 participants in an intensive residential program for weight loss and lifestyle modification (BMI = 41.3 kg/m²), 2) 372 patients evaluated for gastric bypass surgery (BMI = 47.1 kg/m²), and 3) 286 obese control subjects not seeking weight loss treatment (BMI = 43.6 kg/m²). Participants completed the Impact of Weight on Quality of Life‐Lite, a measure of weight‐related quality of life. Responses to the four Sexual Life items (assessing enjoyment, desire, performance, and avoidance) were analyzed by BMI, sex, and group. Results : Higher BMI was associated with greater impairments in sexual quality of life. Obese women reported more impairment in sexual quality of life than obese men for three of four items. Gastric bypass surgery candidates reported more impairment in sexual quality of life than residential patients and controls for most items. In general, residential patients reported levels of impairment greater than or equal to controls. Discussion : Obesity is associated with lack of enjoyment of sexual activity, lack of sexual desire, difficulties with sexual performance, and avoidance of sexual encounters. Sexual quality of life is most impaired for women, individuals with Class III obesity, and patients seeking gastric bypass surgery.     

嘉陵江下游蛇鮈的两性异形与雌性个体生殖力

为了解蛇鮈雌雄间是否存在显著的外部形态差异及雌性个体生殖力情况, 在繁殖期对嘉陵江下游(合川江段)共76尾蛇鮈样本的两性异形、性比及雌性个体生殖力进行分析.结果表明: 嘉陵江下游蛇鮈繁殖群体的性比接近1∶1,且蛇鮈两性的体型大小相同,但局部特征(如头部和躯干部等)呈现出显著的两性异形,如成体雄性蛇鮈的头部、胸鳍和腹鳍均较雌性蛇鮈大,而躯干部的体宽、体高和躯干长则是雌性蛇鮈大于雄性蛇鮈,这可能是性选择长期作用的结果.主成分分析显示,前3个主成分的累积贡献率达75.2%,但雌雄个体间形态特征相互重叠,无法将两者截然分开;利用判别函数对蛇鮈性别进行回判,综合判别准确率为92.1%.蛇鮈雌性个体绝对生殖力在979～19979粒;且与体长和去内脏体质量均呈显著正相关.同历史资料相比,本研究中嘉陵江蛇鮈的生殖力增大显著,这可能是蛇鮈对种群资源量下降和水环境变化主动适应的结果.     

Context-dependent expression of sperm quality in the fruitfly

In most species, females mate multiply within a reproductive cycle, invoking post-copulatory selection on ejaculatory components. Much research has focused on disentangling the key traits important in deciding the outcomes of sperm competition and investigating patterns of covariance among these traits. Less attention has focused on the degree to which such patterns might be context-dependent. Here, we examine whether the expression of sperm viability—a widely used measure of sperm quality—and patterns of covariance between this trait and male reproductive morphologies, change across distinct age classes and across naturally occurring genotypes, when expressed in both heterozygotic (extreme outbred) and homozygotic (extreme inbred) states in the fruitfly Drosophila melanogaster. Older males, and heterozygous males, generally exhibited higher sperm viability. The male age effect seems at least partly explained by a positive association between sperm numbers and viability. First, old males possessed more stored sperm than young males, and second, sperm numbers and viability were also positively associated within each age class. Furthermore, we found a positive association between sperm viability and testis size, but only among heterozygous, old males. These results suggest that sperm quality is a labile trait, with expression levels that are context-dependent and shaped by multiple, potentially interacting, factors.     

流溪河水质的动态特征

流溪河是广州市的一条重要河流,广州市60%的供水都来自于该河。为探讨流溪河水质的动态特征,沿河设立7个监测断面,于2003年1～12月,每月进行一次采样,对主要水质参数进行了分析。结果表明,上游良口断面全年的水质状况明显好于下游的南岗断面。除pH值外,全年南岗断面的溶解氧、高锰酸盐指数、BOD₅、氨氮和总磷均不同程度地超二类水标准,其中以溶解氧超标最为严重,最高值仅为4.94mg·L^-1。污染源分布较多的河段,其枯水期的水质要较丰水期差。从良口断面到南岗断面,pH值和溶解氧呈下降趋势,高锰酸盐指数、BOD₅、氨氮和总磷呈上升趋势,表明流溪河下游水质较差,有机污染较严重。     

Honest signals and sexual conflict: Female lizards carry undesirable indicators of quality

Sex differences in animal coloration often result from sex‐dependent regulatory mechanisms. Still, some species exhibit incomplete sexual dimorphism as females carry a rudimentary version of a costly male trait, leading to intralocus sexual conflict. The underlying physiology and condition dependence of these traits can inform why such conflicts remain unresolved. In eastern fence lizards (Sceloporus undulatus), blue iridophore badges are found in males and females, but melanin pigmentation underneath and surrounding badges is male‐exclusive. We track color saturation and area of badges across sexual maturity, and their relationship to individual quality (body condition and immunocompetence) and relevant hormones (testosterone and corticosterone). Saturation and testosterone were positively correlated in both sexes, but hormone and trait had little overlap between males and females. Saturation was correlated with body condition and immunocompetence in males but not in females. Co‐regulation by androgens may have released females from resource allocation costs of color saturation, even when in high condition. Badge area was independent of testosterone, but associated with low corticosterone in females, indicating that a nonsex hormone underlies incomplete sexual dimorphism. Given the evidence in this species for female reproductive costs associated with ornamentation, this sex‐nonspecific regulation of an honest signal may underlie intralocus sexual conflict.     

Song complexity is associated with habitat quality in an upland passerine

Understanding the influence of intrinsic (genetic and morphological) and extrinsic (geographical, environmental and social) factors on the performance and spatial differentiation of sexual signals, such as bird song, can help identify behavioural indicators of individual quality, habitat degradation and social environment. We used the Iberian Bluethroat Luscinia svecica azuricollis, a migratory bird that breeds in fragmented landscapes dominated by shrublands, as a case study to: (1) assess how a set of acoustic indicators of song performance are driven by intrinsic and extrinsic factors; and (2) contrast deterministic (adaptations to the environmental context and morphological constraints) vs. stochastic (differentiation by geographical isolation) explanations for song differentiation patterns. We explored acoustic indicators of song performance (spectral, temporal and song complexity) in relation to parameters related to genetic structure, body size, habitat type, habitat quality (assessed through a spatially explicit modelling approach) and social context (population abundance and songbird community composition). Then, we explored the contribution of genetic, geographical and environmental dissimilarity to song diversification across space. Our results highlight an association of song spectral variables with genetic structure and a significant connection between song complexity and duration with habitat quality. We found no relationship between social features and acoustic variables, or between song differentiation and genetic or geographical distances. There was, however, a correlation between song differentiation and environmental dissimilarity. We recommend the consideration of song complexity as an indicator of habitat quality.     

Uncertainty in territory quality affects the benefits of usurpation in a Mediterranean wrasse

Individuals should defend sites when the expected benefits ofthe territory exceed the cost of defense. However, if territoryqulaity is unpredictable or difficult to assess, the expectedpattern of territorial behavior is less clear. In a Mediterraneanwrasse, Symphodus ocellatus, mating success is skewed with 2%of nesting males getting more than 20% of the spawning success.Yet, variation in mating success is not explained by any knownphysical characteristic of males or their territories. Instead,females prefer nests with a recent history of mating successbecause males are less likely to desert the offspring she leavesbehind. Thus, territory quality is transient and determinedby interactions between the sexes. I measured the frequencyof territorial takeovers and the uncertainty in mating successamong days at a nest. Observations indicated that S. ocellatusmales usurped their neighbor's successful nests when males wereunsuccessful and larger than their successful neighbor. Sitesthat achieved mating success had a significantly higher probability(0.84) of remaining sucessful between consecutive days thanunsuccessful territories had of becoming successful (0.30).Unsuccessful males obtained higher and more certain fitnessreturns if they usurped a successful neighbor's territory. Interactionswithin and between the sexes drive uncertainty in success, whichinfluences territorial behavior in this species.     

Water quality of the Modder River,South Africa

The Modder River is a relatively small river in the central region of the Free State Province, South Africa and has a mean annual runoff of 184 × 106m³. Botshabelo is a city, which has developed in the catchment area of the river, and its sewage outflows are discharged into the Klein Modder, a tributary of the Modder River. This study was conducted in order to determine the influence of Botshabelo's sewage outflow on the water quality of the river. It was determined that the Modder and Klein Modder Rivers do not generally follow distinctive seasonal patterns in terms of chemical parameters, although NO₃-N and PO₄-P concentrations usually increase with increasing flow and conductivity decreases with increasing flow. Physical parameters such as turbidity, flow and temperature did however follow distinctive seasonal patterns from February 1996 to December 1997, as did phytoplankton growth. Low chlorophyll-a concentrations were exhibited in the winter and higher concentrations during spring. In the Klein Modder River, algal blooms occurred more frequently, and the algal biomass was higher than in the Modder River. This could be ascribed to the higher nutrient concentrations and lower flow velocities in the former. The inflow of the Klein Modder River into the Modder River caused on average, 112% increase in PO₄-P, 171% increase in NO₃-N, 50% increase in chlorophyll-a concentration, and 230% increase in E. coli counts.     

Offspring viability benefits but no apparent costs of mating with high quality males

Traditional models of sexual selection posit that male courtship signals evolve as indicators of underlying male genetic quality. An alternative hypothesis is that sexual conflict over mating generates antagonistic coevolution between male courtship persistence and female resistance. In the scarabaeine dung beetle Onthophagus taurus, females are more likely to mate with males that have high courtship rates. Here, we examine the effects of exposing females to males with either high or low courtship rates on female lifetime productivity and offspring viability. Females exposed to males with high courtship rates mated more often and produced offspring with greater egg-adult viability. Female productivity and lifespan were unaffected by exposure to males with high courtship rates. The data are consistent with models of sexual selection based on indirect genetic benefits, and provide little evidence for sexual conflict in this system.