河滨湿地不同植物群落根系分布特征与土壤理化性状的关系——以黄河中游荥阳段为例

在黄河中游郑州荥阳段,选择了5种河滨湿地植物群落进行根系和土壤性状特征研究,以期阐明不同植物群落的根系分布规律与土壤性状的关系,为河滨湿地植物群落组成以及土壤质量恢复提供科学参考。结果表明(1)在0—40 cm土层,根生物量密度与根长密度的平均值均表现为：芦苇群落(Phragmites australis)和芦苇-狗牙根(Cynodon dactylon)群落均大于芦苇-拂子茅(Calamagrostis epigeios)-狗牙根群落、拂子茅-狗牙根群落、拂子茅-狗牙根-水莎草(Juncellus serotinus)群落。拂子茅-狗牙根、芦苇-拂子茅-狗牙根、拂子茅-水莎草-狗牙根三种植物群落类型下根生物量密度、根长密度在0—20 cm表层土壤较大,芦苇群落和芦苇-狗牙根群落的根生物量密度、根长密度在10—40 cm的土层较大。(2)黄河河滨湿地芦苇群落、芦苇-狗牙根群落的土壤以粉粒为主,拂子茅-狗牙根群落、芦苇-拂子茅-狗牙根群落、拂子茅-狗牙根-水莎草群落的土壤主要以砂粒为主。在0—40 cm土层,芦苇群落、芦苇-狗牙根群落的土壤含水率、土壤有机质、有效氮和有效磷含量均显著高于...     

塔里木河沿岸不同生境下胡杨(Populus euphratica)群落的空间分布格局及关联性

以塔里木河河岸边、过渡带、沙漠边缘样地调查数据为基础,采用成对相关函数g(r)分析了3个生境胡杨群落的空间分布格局及关联性。结果表明:不同生境下胡杨种群的结构特征存在差异。胡杨种群年龄结构在河岸边样地呈反"J"型,属于增长型种群;过渡带样地呈偏正态分布,属于稳定型种群;沙漠边缘样地呈典型的反"L",属于衰退型种群。不同生境下胡杨群落的空间分布格局表现也不同。河岸边样地,花花柴(Karelinia caspia)、假苇拂子茅(Calamagrostis pseudophragmites)、芦苇(Phragmites australis)和多枝柽柳(Tamarix ramosissima)分布均呈聚集分布,而罗布麻(Apocynum venetum)主要呈随机分布;过渡带样地,罗布麻和骆驼刺(Alhagi sparsifolia)表现为聚集分布,而黑果枸杞(Lycium ruthenicum)和胡杨小尺度上呈聚集分布,随着尺度增加,表现为随机分布;沙漠边缘样地,白茎盐生草(Halogeton arachnoideus)呈聚集分布。不同生境下胡杨群落的空间关联表现也不同。河岸边样地,胡杨与假苇拂子茅、胡杨与大叶白麻(Poacynum hendersonii)、假苇拂子茅与芦苇、芦苇与多枝柽柳的关联性均为正相关;过渡带样地,铃铛刺(Halimodendron halodendron)与黑果枸杞、黑果枸杞与花花柴、黑果枸杞与铃铛刺、铃铛刺与骆驼刺、花花柴与骆驼刺、骆驼刺与花花柴、蓼子朴(Inula salsoloides)与花花柴均呈正相关,而罗布麻与多枝柽柳呈负相关;沙漠边缘样地,刺沙蓬(Salsola ruthenica)与白茎盐生草呈负关联。     

江西南矶湿地斑背大尾莺食性初步分析

为了填补斑背大尾莺食性研究的空白和比较其繁殖期和非繁殖期是否有食性差异,于2011年4月繁殖期,在江西南矶湿地用望远镜观察和录像机拍摄斑背大尾莺亲鸟育雏行为,记录育雏食物的种类和数量;在11月秋季非繁殖期,斑背大尾莺专项环志过程中采集7只意外死亡的个体,进行实验室胃容物解剖分析。两种分析方法分别得出:1)春季取食动物性食物,主要有直翅目蝼蛄科成虫或幼虫、鳞翅目成虫或幼虫、蜻蜓目的成虫,蛛形纲的小型蜘蛛;2)秋季食物由动物性食物(70.24%)和植物性食物(29.76%)组成,动物性食物主要为鞘翅目、直翅目、蜻蜓目、鳞翅目、蜘蛛目等节肢动物,植物性食物为一些植物种子和少量的叶片组织。本研究表明,繁殖期和非繁殖期斑背大尾莺食性有差异,这种差异性是随季节变化生境中的食物组成不同,及育雏期雏鸟需高蛋白营养食物而导致的。     

斑背大尾莺的白色型

2007年5月20日于辽宁省东港市孤山镇苇田——鸭绿江口湿地国家级自然保护区核心区,在冬季未收割的残留枯草斑块中发现一只白色的雀鸟(封4图片),不鸣叫,飞行姿态及尾部展示与大尾莺(Megalurus)颇为相似。经多次观察发现有雄性大尾莺追随之。23日设网将其捕获,并拍照、称重、度量。最后确定该鸟为雌性斑背大尾莺(Megalurus pryeri sinensis)的白色型(white morph)。该鸟羽色以白色为主,两肋及肛羽沾黄,头顶略现灰,右翼前侧第二枚飞羽前缘距羽端0.2cm有一长0.5cm的黑褐斑。上喙黑褐、下喙肉黄、跗跖肉色等特征与正常大尾莺无异。测量数据如下:…     

红碱淖东方大苇莺繁殖生态

2012年5～7月,在陕西红碱淖对东方大苇莺的繁殖生态进行了研究。结果表明,东方大苇莺5月末迁来繁殖,营巢于芦苇丛中,巢口向上呈深杯状,由枯芦苇和芦苇絮编织而成。对17个巢的巢参数进行了测量:巢外径(11.85±0.216)cm,巢内径(5.87±0.101)cm,巢深(6.49±0.166)cm。巢距地面高度(106.00±4.421)cm,约位于芦苇高度的2/5处。平均窝卵数(4.67±0.188)枚,卵重为(2.70±0.044)g,卵长径为(21.93±0.13)mm,卵短径为(15.81±0.06)mm。孵化期为(15～18)d,孵化率为78.8%,巢雏成活率为95.2%。雏鸟的体重、体长的生长符合Logistic曲线方程拟合。芦苇的高度和密度是制约东方大苇莺巢址选择的主要因素,恶劣天气和大杜鹃巢寄生是影响繁殖成效的主要原因。     

2008年春鄱阳湖区斑背大尾莺状况

2008年1月下旬至2月上旬在中国南方广大地区发生冻雨雪灾害,给在鄱阳湖区越冬的斑背大尾莺(Locustella pryeri)带来不利影响,据3月上旬的调查,原本在江西鄱阳湖南矶湿地国家级自然保护区内广泛分布的斑背大尾莺已变得十分稀少.     

生境破碎化对丹顶鹤巢位选择的影响

1985、1995年和1998年4－5月,采用查阅保护区历史资料及实地调查方法,对辽宁双台河口国家级自然保护区内丹顶鹤（Grus japonensis)的主要营巢地－东郭苇场和赵圈河苇场的生境破碎化及丹顶鹤在2片苇场中的营巢状况和繁殖种群数量变动情况作了系统的考察和研究,发现丹顶鹤的营巢生境破碎严重,已由成片的芦苇湿地变成91个斑块,其中最小营巢斑块面积为0．37km^2,最小巢间距为304m,比过去资料记载的最小巢区面积缩小了0．72km^2,但繁殖种群数量变动不大,多年来一直维持在30对左右,丹顶鹤为了适应变化了的环境,已采取了缩小巢区面积的生态适应对策。     

斑背大尾莺sinensis亚种的繁殖生物学

斑背大尾莺（Megalurus pryeri）为东亚特有鸟类,数量稀少（常家传,1995;马敬能等,2000）,2003年IUCN世界濒危物种红皮书将斑背大尾莺列为易危物种（汪松、解焱,2004）。斑背大尾莺有2个亚种,指名亚种（M．P．pryeri）仅在日本本州岛北部的Kanto平原北部繁殖,越冬区在本州岛中部的太平洋沿岸（Fujitaand Nagata,1997）;sinensis亚种在我国仅见于湖北汉口（冬候鸟）、河北秦皇岛（旅鸟）和辽宁朝阳地区（繁殖鸟？）（郑作新,1987）。     

白洋淀东方大苇莺繁殖生境质量评价

白洋淀湿地自然保护区是东方大苇莺在华北地区的重要繁殖栖息地之一.于2011年6—7月采用样线法在保护区内开展东方大苇莺巢位调查,累计记录巢位112处,在此基础上,采用生态位因子分析模型对保护区内东方大苇莺的繁殖生境质量进行分析评价.结果表明:东方大苇莺偏好在高程相对较高、远离人类活动干扰的旱地芦苇景观内营巢,而避免在其他景观内营巢;2011年,白洋淀湿地自然保护区内东方大苇莺繁殖适宜生境总面积2474.69 hm2,占保护区总面积的7.6%,其中最适宜生境面积1131.19 hm2,仅占保护区总面积的3.5%.最适宜生境呈圈层状结构分布,集中分布于现分隔2处的白洋淀东部的大麦淀、烧车淀核心区及其周边区域.为保护东方大苇莺繁殖生境,建议将大麦淀和烧车淀核心区合并,形成一个面积更大、分布相对集中的核心区,并以最大限度地保护和维持白洋淀湿地自然景观的规模为目标,合理设置缓冲区.     

斑背大尾莺鄱阳湖繁殖亚群初报

斑背大尾莺(Locustella pryeri)为远东鸟种,主要分布于日本和中国,零星见于俄罗斯极东部、蒙古国东部、朝鲜和韩国,被视为易危鸟种(VU)[1~3]。以往中国鸟类学界多以种名Megalurus pryeri称之,并将该种的中国种群全部视作汉口亚种(sinensis)[4~10]。据记载,斑背大尾莺在我国东北     

The Effect of Marsh Age on Ecosystem Function in a Rapidly Transgressing Marsh

Ecosystems - Sea-level rise is leading to the migration of marshes into coastal forests throughout North America. Marsh migration represents a primary mechanism for marsh survival in the face of...     

Arylsulfatase Activity in Salt Marsh Soils

The presence of arylsulfatase(s) was confirmed in salt marsh soils. The temperatures of maximum activity and inactivation, the pH range over which the enzyme was active, and the K_m values were similar to those of soil enzymes. Unlike soil arylsulfatases, however, the salt marsh enzymes do not appear to be repressed by sulfate. It is postulated that these enzymes may be necessary for the initiation of arylsulfate ester metabolism.     

中国湿地简述

对中国湿地的分布、主要类型、湿地的资源特点、生态特点以及湿地在环境保护、调节气候、物质生产等方面作了简要阐述,并简要分析了中国湿地的保护现状,对湿地的保护提出了几点建议。     

Sediments in Marsh Ponds of the Gulf Coast Chenier Plain: Effects of Structural Marsh Management and Salinity

Physical characteristics of sediments in coastal marsh ponds (flooded zones of marsh associated with little vegetation) have important ecological consequences because they determine compositions of benthic invertebrate communities, which in turn influence compositions of waterbird communities. Sediments in marsh ponds of the Gulf Coast Chenier Plain potentially are affected by (1) structural marsh management (levees, water control structures and impoundments; SMM), and (2) variation in salinity. Based on available literature concerning effects of SMM on sediments in emergent plant zones (zones of marsh occasionally flooded and associated with dense vegetation) of coastal marshes, we predicted that SMM would increase sediment carbon content and sediment hardness, and decrease oxygen penetration (O₂ depth) and the silt-clay fraction in marsh pond sediments. Assuming that freshwater marshes are more productive than are saline marshes, we also predicted that sediments of impounded freshwater marsh ponds would contain more carbon than those of impounded oligohaline and mesohaline marsh ponds, whereas C:N ratio, sediment hardness, silt-clay fraction, and O₂ depth would be similar among pond types. Accordingly, we measured sediment variables within ponds of impounded and unimpounded marshes on Rockefeller State Wildlife Refuge, near Grand Chenier, Louisiana. To test the above predictions, we compared sediment variables (1) between ponds of impounded (IM) and unimpounded mesohaline marshes (UM), and (2) among ponds of impounded freshwater (IF), oligohaline (IO), and mesohaline (IM) marshes. An a priori multivariate analysis of variance (MANOVA) contrast indicated that sediments differed between IM and UM marsh ponds. As predicted, the silt-clay fraction and O₂ depth were lower and carbon content, C:N ratio, and sediment hardness were higher in IM than in UM marsh ponds. An a priori MANOVA contrast also indicated that sediments differed among IF, IO, and IM marsh ponds. As predicted, carbon content was higher in IF marsh ponds than in ponds of other impounded marsh types. In contrast to our predictions, C:N ratio and sediment hardness were lowest and silt-clay fraction and O₂ depth were highest in IO and IM marsh ponds. Our results indicated that SMM has affected physical properties of sediments in coastal marsh ponds. Moreover, sediments in IF marsh ponds were affected more so than were those in IO and IM marsh ponds. Our results, in conjunction with those of previous studies, indicated that sediments of marsh ponds and emergent plant zones differed greatly. We predict that changes in pond sediments due to SMM will promote greater epifaunal macroinvertebrate biomass, which in turn should attract larger populations of wintering waterbirds. However, waterbirds that filter or probe soft sediments may be negatively affected by SMM because of the expected decrease in infaunal invertebrate biomass.     

Ammonium Transformation in a Nitrogen-Rich Tidal Freshwater Marsh

The fate and transport of watershed-derived ammonium in a tidal freshwater marsh fringing the nutrient rich Scheldt River, Belgium, was quantified in a whole ecosystem ¹⁵N labeling experiment. In late summer (September) we added ¹⁵N-NH₄⁺ to the flood water entering a 3477 m² tidal freshwater marsh area, and traced the ammonium processing and retention in four subsequent tide cycles. In this paper we present the results for the water-phase components of the marsh system and compare them to a similar experiment conducted in spring/early summer (May). Changes in concentration and isotopic enrichment of NO₃⁻ + NO₂⁻, N₂O, N₂, NH₄⁺ and suspended particulate nitrogen (SPN) were measured in concert with a mass balance study. All analyzed N-pools were labeled, and 49% of the added ¹⁵NH₄⁺ was retained or transformed. The most important pool for ¹⁵N was nitrate, accounting for 17% of ¹⁵N-transformation. N₂, N₂O and SPN accounted for 2.4, 0.02 and 1.4%, respectively. The temporal and spatial patterns of ¹⁵N transformation in the water phase component of the system were remarkably similar to those observed in May, indicating good reproducibility of the whole ecosystem labeling approach, but the absolute ammonium transformation rate was 3 times higher in May. While the marsh surface area was crucial for nitrification in May this was less pronounced in September. Denitrification, on the other hand, appeared more important in September compared to May.     

Trophic Cascades Uncoupled in a Coastal Marsh Ecosystem

The Mediterranean population of the exotic eastern mosquitofish Gambusia holbrooki (Agassiz 1859) (Osteichthyes, Poeciliidae) has been held responsible for causing eutrophication due to zooplankton removal and phytoplankton enhancement, however no experimental evidence exists of this. To test this allegation, an enclosure experiment was conducted in spring in an oligohaline coastal marsh. The manipulation of fish density had profound effects on zooplankton, whose density greatly decreased when the occurrence of mosquitofish increased. Cladocerans and ostracods were more affected by mosquitofish than cyclopoid copepods, whilst rotifer density was not modified. Changes in zooplankton density did not cascade to lower trophic levels as no differences were observed between the chlorophyll concentration in fish and fish-less enclosures. This is because zooplankton was dominated by species with low filter-feeding rates, such as small cladocerans. In consequence, the total macrophyte standing crop was not affected. The only benthic macroinvertebrate species whose density increased in the absence of eastern mosquitofish was the mud snail P. acuta. Higher numbers of snails explain why the standing crop of the filamentous green algae Oedogonium sp. decreased in fish-less enclosures. The density of chironomid midge larvae did not increase in fish-less enclosures, because eastern mosquitofish forage on them mainly during summer, when zooplankton has already been depleted; nor were damselflies, probably because they are too large. Nitrogen concentration decreased after fish exclusion, but phosphorus concentration remain unchanged. In conclusion, it was found that the eastern mosquitofish affect zooplankton of the Mediterranean oligohaline lagoons considerably, but they do not enhance phytoplankton growth, because the system is bottom-controlled by submerged macrophytes.     

Tracer Analysis of Methanogenesis in Salt Marsh Soils

Differences in paths of carbon flow have been found in soils of the tall (TS) and short (SS) Spartina alterniflora marshes of Sapelo Island, Ga. Gaseous end products of [U-¹⁴C]glucose metabolism were ¹⁴CO₂ and ¹⁴CH₄ in the SS region and primarily ¹⁴CO₂ in the TS region. Sulfate concentration did not demonstrably affect glucose catabolism or the distribution of end products in either zone. [U-¹⁴C]acetate was converted to ¹⁴CO₂ and ¹⁴CH₄ in the SS soils and almost exclusively to ¹⁴CO₂ in the TS soils. Sulfate concentration did not affect acetate metabolism in the SS soils; however, a noticeable effect of sulfate dilution was seen in TS soils. Sulfate dilution in TS samples resulted in increased methane formation. Total glucose and acetate metabolism were similar in TS and SS soils despite differences in end products. A microbial community characterized by fermentative/sulfate-reducing processes has developed in TS soils as opposed to the fermentative/methanogenic/sulfate-reducing community found in SS soils.