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娘子关泉域藻类植物的初步研究 总被引:11,自引:0,他引:11
1984~2000年间,对娘子关泉域的藻类植物进行了15次采集,共采得藻类植物标本200余号。经鉴定,有107种,隶属7门,32科,49属。其中,以绿藻门的种类最多,有13科,19属,45种。其次是裸藻门,有2科,7属,26种。排在最后的是轮藻门,有1科,1属,3种。群落主要包括8类,即刚毛藻-红毛菜群落(Cladophora Bangia community),刚毛藻群落(Cladophora community),拖拉藻-轮藻群落(Chara Thorea community),弯枝藻-拖拉藻群落(Composopogon-Thorea community),水绵-双星藻群落(Spirogyra Zygnema community),无隔藻群落(Vaucheria community),串珠藻群落(Batrachospermum community)和泡状饶氏藻群落(Jaoa community)。其中,有的群落类型已趋于消失或消失,许多种类已成为濒危物种,其原因主要是人为因素造成藻类植物生存环境的改变或破坏。本文也提出了相应的保护对策。 相似文献
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四平转山湖水库地区昆虫多样性的初步研究 总被引:8,自引:0,他引:8
昆虫个体虽小 ,但种类繁多 ,全世界约有 140万种生物 ,而昆虫约占 5 3.5 7%。昆虫与人类有着极为密切的关系 ,如害虫对人类健康和国民经济有着重要影响 ,但绝大多数种类的昆虫对人类是有益或中性的 ,有的是显花植物的传粉者 ;有的是害虫的天敌 ;生活在土壤内的昆虫能促进腐殖质形成与土壤通气 ,提高土地的肥力 ;而有些昆虫的产物 ,如蜂蜜、丝、白蜡等是食品、医药及工业原料 ;还有许多昆虫用于环境净化和科学研究等多个领域[1] 。因此对昆虫研究愈来愈引起人们的重视[14~ 17] ,我国许多昆虫工作者在不同地区对不同昆虫类群进行了调查研究 ,… 相似文献
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吉林白城地区草原栗斑腹(巫鸟)窝卵数、营巢成功率和繁殖成功率的研究 总被引:4,自引:1,他引:4
对分布于吉林白城地区草原生境中栗斑腹巫鸟的窝卵数、营巢成功率和繁殖成功率的初步研究结果表明 ,繁殖期栗斑腹巫鸟种群的平均窝卵数为 5 .0 9± 0 .5 8枚 /巢 ;窝卵数与产卵期、出巢数与产卵期、窝卵数与卵大小之间呈负相关 ,产卵期与孵化率之间存在极显著的负相关关系 ,巢外径与窝卵数之间存在显著的正相关关系 ,巢的其余指标均与窝卵数呈正相关 ;平均孵化期为 12± 0 .4 9d ,孵化率为 36 .3% ,繁殖成功率为 11.11% ;7日龄以上的雏鸟群体大小为 2 .5 6± 1.5 3只 ,栗斑腹巫鸟的雏鸟存活率为 2 7.6 9% . 相似文献
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2004年4月-2005年4月,对珠江广州河段轮虫群落结构特征进行了初步研究。经鉴定,共发现轮虫65种(包括亚种),其中西氏三肢轮虫(Filinia novaezealandiae)、华美腔轮虫(Lecane elegans)为我国的新记录种。优势种为裂痕龟纹轮虫(Anuraeopsis fissa)、角突臂尾轮虫(Brachionus angularis)、尾突臂尾轮虫(Brachionus caudatus)、Filinia novaezealandiae、暗小异尾轮虫(Trichocerca pusilla)和微型多突轮虫(Liliferotrocha subtilis)。调查发现径流量对轮虫密度有重要影响,轮虫的两次密度高峰分别出现在春末夏初和秋季。丰水期,轮虫密度较低;枯水期前期,轮虫密度较高;枯水期后期,轮虫密度较低。此外,轮虫种群还受到温度、盐度等因素的影响。研究结果表明轮虫在河流生态系统中具有重要作用。 相似文献
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描述了北方菜园优势跳虫四刺泡角跳(Ceratophysella duplicispinosa)的胚胎发育及胚后发育过程。结果表明:①四刺泡角跳为聚产卵,每窝卵数22-53粒,卵粒D=220μm。②其胚胎发育历时约8.3d(200h),行完全均等卵裂,以内陷方式形成二胚层;③组织器官分化早期背面中部出现凹陷,成为头部与胸腹部最早的界限,同时在腹面出现附肢原基;④无体节幼虫期的触角、口器、足、腹管、弹器及腹部尾叶等器官都以附肢原基的形式出现,至孵化前期显现出各器官形态:出壳前3d开始出现一对红色眼斑。⑤胚后发育(自孵化出壳至首次产卵)历时29d,体色先后为白色(初孵化幼体)、棕红至灰色(亚成体)、紫黑色(成体)。 相似文献
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水母类是海洋生态系统中非常重要的一个类群。根据 1 959年以来在渤海进行的几次较为全面的调查资料 ,对渤海水母类的种类组成、数量分布与季节变化作了较为详细的研究。共记录到水母类 4 1种 ,其中水螅水母 35种 ,钵水母 4种 ,栉水母 2种。主要以近岸低盐类型为主 ,高盐种类少并且出现时间短。渤海水母类密度的季节变化有 3个高峰 ,出现在冬季 ,夏季和秋季 ,分别由八斑芮氏水母、酒杯水母属、和平水母属、五角水母构成。渤海水母类的分布具有一定的季节特点 ,冬季和夏季以莱州湾密度最高 ,春季为渤海湾最高 ,秋季为中央海区最高。辽东湾水母类的密度在各个季节都不算高 相似文献
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南亚热带森林不同演替阶段土壤种子库的初步研究 总被引:42,自引:2,他引:42
本文对鼎湖山不同演替阶段的森林(马尾松林、针阔叶混交林、季风常绿阔叶林)的土壤种子库进行了初步研究.分别从各个阶段的样地内抽取4或8个1×1m的小样地,分三层(共10cm厚)采集土样,带回实验室,通过萌发法观察记录其土壤种子库状况.通过统计分析,其结果如下:1.种子数量和物种多样性一般随演替发展而减少,种子数目以3—5cm厚土层为最多.2.各演替阶段土壤种子库的种类组成均以草本植物为主.3.在光照和湿度基本一致的情况下,萌发种子数与温度成正相关.4.雨季取的种子数目较旱季多,且种类组成有所不同.这是因为南亚热带森林内植物种子的休眠期短,在旱季采集土样时许多种的种子尚未下落.5.种子库组成与地上植物相关性不明显,但演替早期阶段的相关性比演替后期更密切。 相似文献
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青弋江芜湖段轮虫群落结构和物种多样性的初步研究 总被引:9,自引:0,他引:9
20 0 3年 1- 12月 ,对青弋江芜湖段轮虫群落结构和物种多样性的周年动态进行了初步研究 ,并分析了轮虫密度与水温、水体叶绿素a浓度和水流量等环境因子的关系 ,以便为我国轮虫区系以及河流中轮虫密度的季节变化规律的进一步研究提供基础资料。经鉴定 ,共发现轮虫 10 4种 ,其中钳枝巨头轮虫 (Cephalodellaforceps)、长趾巨头轮虫 (C .macrodactyla)、尾钩巨头轮虫 (C .mucronata)、奇槌巨头轮虫 (C .evabroedi)、突纹腔轮虫 (Lecanehornemanni)、爱沙腔轮虫 (L .elsa)、长趾似月腔轮虫 (L .lunarisacus)和泛热三肢轮虫 (Filiniacamasecla)等 8种轮虫为我国亚热带地区的新记录种 ;优势种为螺形龟甲轮虫 (Keratellacochlearis)、广生多肢轮虫 (Polyarthravul garis)和无尾无柄轮虫 (Ascomorphaecaudis)。 1- 4月 (汛期前 ) ,轮虫总密度与水温、叶绿素a浓度之间均呈现出显著的正相关关系 (r =0 .5 33,P <0 .0 5 ;r=0 .5 4 8,P <0 .0 5 ) ;而在 5 - 9月 (汛期 ) ,轮虫总密度与水流量之间表现出显著的正相关关系 (r =0 .5 80 ,P <0 .0 1) ;10 - 12月 (汛期后 ) ,轮虫总密度和水温、叶绿素a浓度和水流量之间都表现出显著的正相关性 (多元回归 ,R2 =0 .6 80 ,P <0 .0 5 ) ;水流量对 10 - 12月轮虫密度的影响最大 相似文献
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宁夏沙坡头地区藻类及其分布 总被引:13,自引:2,他引:13
通过野外采样,室内培养、观察、鉴定,研究了沙坡头地区藻类多样性和分布特点,并为当地藻类资源利用提出建议。研究发现沙坡头地区藻类植物共计40种(包括1变型),其中蓝藻17种,绿藻10种,硅藻9种,裸藻4种,全为普生种,陆地生境中种类最丰富。亚气及陆地生境中蓝藻在种类数(除灌溉林地结皮)、生物量方面占主导地位;贫瘠水体生境中硅藻占主要地位,营养较丰富水体中绿藻处于优势地位。另外,陆生生境中多以具鞘微鞘藻Microcoleus vaginatus为优势种,小席藻Phormidium tenue为主要种。 相似文献
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The summer macroinvertebrate fauna was studied in six central Florida monomictic lakes during July, 1973. No direct relationships were found between physiochemical conditions and species diversity. Of the 22 species of benthic organisms recorded, only four species were found in all the lakes. Mean species diversity (d) values for the lakes ranged from 0.735 to 1.731. 相似文献
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Kiørboe T 《Oecologia》2008,155(1):179-192
The performance of individual phytoplankton species is strongly governed by the thermal stratification’s impact on vertical
mixing within the water column, which alters the position of phytoplankton relative to nutrients and light. The present study
documents shifts in phytoplankton structure and vertical positioning that have accompanied intensified long-term stratification
in a natural ecosystem. Ordination analysis is used to extract gradients in phytoplankton composition in Lake Tahoe, an extremely
nutrient-poor lake, over a 23-year period of records. Community structure in the 1980s was associated most strongly with resource
availability (low nitrogen to phosphorus ratios, deeper euphotic zone depth), while intensified stratification dominated the
phytoplankton structure since the late 1990s. Within diatoms, small-sized cells increased with reduced mixing, suggesting
that suppressed turbulence provides them with a competitive advantage over large-sized cells. Among the morphologically diverse
chlorophytes, filamentous and coenobial forms were favored under intensified stratification. The selection for small-sized
diatoms is accompanied by a shoaling trend in their vertical position in the water column. In contrast, the motile flagellates
displayed a deeper vertical positioning in recent years, indicating that optimal growth conditions shifted likely due to reduced
upwelling of nutrients. As the thermal stratification of lakes and oceans is strongly linked to climate variables, the present
study confirms that climate warming will alter phytoplankton structure and dynamics largely through effects on nutrient availability
and sinking velocities. Intensified stratification should favor the expansion of small-sized species and species with the
capability of buoyancy regulation, which may alter primary productivity, nutrient recycling, and higher trophic productivity.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
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The protozoan fauna and species richness in the pelagic zone of 15 Japanese lakes were investigated in 1996 using polyurethane foam (PF) substrates. The most common species were flagellates, such as Cryptomonas erosa, Oikomonas termo, and Pleuromonas jaculans. Cinetochilum margaritaceum and Actinophrys sol were the most common species of the Ciliata and Sarcodina, respectively. The similarity of species occurrence was calculated from presence/absence data, but this revealed no clear trend with respect to the influence of lake properties such as trophic state, surface area, or mean depth. The occurrence pattern of Protozoa was most similar in L. Chuzenji and L. Biwa (north basin), two oligomesotrophic natural lakes. Log species richness was positively correlated with log total phosphorus (r = 0.54, P < 0.05) and negatively with log mean depth (r = −0.58, P < 0.05). The diversity index (Margalef's formula), highly correlated with the total species number (r = 0.85, P < 0.01), was negatively correlated with log lake area (r = −0.71, P < 0.01). The logarithm of Phytomastigophora number was positively correlated with log total nitrogen (r = 0.53, P < 0.05), and the logarithm of Ciliata number was negatively correlated with log lake area (r = −0.55, P < 0.05). The species richness of Protozoa on PF substrates was determined by both the nutrient status of the lake and the distance from the location of the suspended PF substrate to the lake bottom or shore. Received: September 25, 1999 / Accepted: January 6, 2000 相似文献
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Synopsis The white perch,Morone americana, is an east coast estuarine species that invaded Lake Erie in the 1950's, but did not increase in abundance until the mid 1970's. We studied its distribution and feeding during spawning in the Sandusky River, Ohio in 1981–1983. White perch were present in the area from early April through May, but abundance was highest on bedrock riffles about 45 km upstream from Lake Erie. Spawning activity peaked in the last week of April when temperatures approached 18°C. White perch collected in early April had eaten walleye,Stizostedion vitreum vitreum, eggs. As spawning activity of white perch increased, feeding activity declined, and most fish collected during late April contained no food. Egg predation increased again in May, but the eggs eaten then were those of white bass,Morone chrysops, white perch, and possibly other species. We have no evidence that egg predation by white perch has affected walleye or white bass recruitment, but it could become a problem if white perch continue to increase in abundance. 相似文献
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Due to the passive dispersal, tardigrades have been traditionally considered unsuitable for biogeographical studies. However, this paper provides some biogeographical and biological data supporting the possibility of using those animals to solve biogeographical problems at continental level. 相似文献
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在长江中下游浅水湖泊的水生植被中,沉水植被是最重要的植被类型。研究沉水植被资源量对湖泊生态系统及渔业管理都具有重要意义。本工作调查梁子湖、牛山湖和保安湖沉水植被的种类、生物量及覆盖度,并与以前研究相比较,以了解三个湖泊沉水植被资源现状以及变动趋势。 相似文献
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Normans Lagoon and 3-Gum pond are small floodplain water bodies adjacent to the Murray River, south-eastern Australia, and
often have a visible film/sheen across their surface. Since few studies have provided quantitative comparisons of the surface
and subsurface layer communities of shallow freshwater lakes, we determined the contributions of the surface and subsurface
populations to overall algal biomass when a surface film was visible, and when it was not visible. We examined the algae and
cyanobacteria present at the air–water interface of each water body, and compared the findings with those for the water immediately
below the surface, and for the overall water column. The algal groupings Trachelomonas spp., other Euglenophyceae (principally Euglena spp.), Chlorophyceae and Cyanobacteria usually comprised >95% of the measured biovolume within all samples. Samples from
the air–water interface were considerably enriched (up to 200-fold) with respect to algal biovolume, whether or not a visible
surface film was present, and elevated cell counts were observed within the air–water interface for motile organisms such
as Trachelomonas spp. and green unicellular flagellates. The reverse was true for the cyanobacterium Planktolyngbya however, with greater concentrations occurring at depth. In terms of its contribution to the overall algal/cyanobacterial
populations within each water body, the surface layer was found to be responsible for <1–20% of the biovolume over the entire
water column. Multivariate statistical analysis confirmed there were significant differences between the communities of the
air–water interface and those of the water below, and that these differences occurred both in the presence and absence of
a visible surface film/sheen.
Handling editor: D. Ryder 相似文献
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An evaluation of sampling techniques was conducted on Highland Sourveld in the Natal Drakensberg. The quadrat, Levy bridge, step point, wheel point, metric belt transect and 't Mannetje & Haydock methods were used. In order to compare these methods the scores were standardized against the wheel point. The results of analyses of variance showed that the quadrat and point techniques were the most consistent. The metric belt transect and 't Mannetje & Haydock methods were shown to be not suitable for detailed botanical analysis. Operator differences and time of day had little effect on the results. It is concluded that the wheel point method is most suitable for determining grassland species composition in the Natal Drakensberg. 相似文献
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Species richness, composition and abundance of the bryophyte diaspore bank of Central European temperate mixed forests were compared with the forest-floor bryophyte assemblage. The impact of environmental variables and anthropogenic disturbances, including tree species composition, stand structure, microclimate, light conditions, soil and litter properties, management history, and landscape properties, potentially influencing bryophyte diaspore bank assemblages were explored. Thirty-four, 70–100 years old mixed stands with differing tree species composition were examined in the ?rség National Park, Western Hungary. The diaspore bank was studied by soil collection and cultivation, and data were analysed by multivariate methods. Contrary to the forest-floor bryophyte assemblage, where substrate availability, tree species composition and stand structure were the most influential environmental variables, the composition and abundance of the diaspore bank was mainly affected by site conditions (microclimate, litter and soil properties). Species richness of the bryophyte diaspore bank was lower than that of the forest-floor bryophyte assemblage. Short-lived mosses (colonists, short-lived shuttles) were dominant in the diaspore bank, as opposed to the forest-floor bryophyte community, where perennial mosses dominated. In the studied forests, the importance of the bryophyte diaspore bank was relatively low in the regeneration and maintenance of the forest-floor bryophyte vegetation. 相似文献