Reintroducing wood to streams in agricultural landscapes: changes in velocity profile,stage and erosion rates

Historically, perceived increases in erosion and flooding levels have been attributed to in‐stream wood and used to justify its removal from streams and rivers around the world. More recently, recognition of the adverse morphological and biological impacts caused by this removal has led to rehabilitation projects that actively reintroduce wood to streams. However, a perception remains amongst some members of the general community that wood additions increase the likelihood of flooding and erosion in the target streams. To test whether there was a basis for this perception, we experimentally added wood to eight streams across southwest Victoria and Gippsland, Australia. The velocity, stage and bed and bank erosion rates were compared with those of unaltered reaches. We detected localized changes in the velocity and stage parameters but that these were unlikely to operate at the reach‐scale. Bed erosion rates, where maximum erosion was assumed if pins were not recovered, showed increased erosion due to wood additions but this was not supported by channel shape analyses, which identified short‐term increases in the variability of the channel shape, followed by longer‐term stability at treatment sites. We found no clear evidence of increased longer‐term rates of erosion or flooding associated with the introduction of wood to streams over the 18‐month study period. It remains important to carefully design rehabilitation works, but the lack of adverse effects on stream morphology and increased variability of the in‐stream environment suggests improved habitat diversity, supporting the use of wood addition as a stream rehabilitation technique. Copyright © 2008 John Wiley & Sons, Ltd.     

Effects of large woody debris on surface structure and aquatic habitat in forested streams,southern interior British Columbia,Canada

It is well known that large woody debris (LWD) plays an important functional role in aquatic organisms' life. However, the influence of LWD on channel morphology and aquatic environments at watershed levels is still unclear. The relationships between wood and surface structure and aquatic habitat in 35 first through fifth order streams of southern interior British Columbia were investigated. Study streams in the channel networks of the study watersheds were classified into four size categories based on stream order and bankfull width: Stream size I: bankfull width was less than 3 m, Stream size II: 3–5 m, Stream size III: 5–7 m, Stream size IV: larger than 7 m. We found the number of functional pieces increased with stream size and wood surface area in stream sizes I, II and III (24, 28 and 25 m²/100 m², respectively) was significantly higher than that in stream size IV (12 m²/100 m²). The contribution of wood pieces to pool formation was 75% and 85% in stream sizes II and III, respectively, which was significantly higher than those in stream size I (50%) and size IV (25%). Between 21% and 25% of wood pieces were associated with storing sediment, and between 20% and 29% of pieces were involved in channel bank stability in all study streams. Due to long‐term interactions, LWD in the intermediate sized streams (Size II and III) exhibited much effect on channel surface structure and aquatic habitats in the studied watersheds. Copyright © 2008 John Wiley & Sons, Ltd.     

Spatial distribution of large wood jams in streams related to stream‐valley geomorphology and forest age in Northern Michigan

Geomorphology at the scale of stream valleys influences smaller scale processes that give rise to spatially distributed patches, including large wood jams (LWJ) in streams. Understanding the spatial distribution of LWJ along streams with reference to large‐scale geomorphology is valuable for understanding stream and riparian interactions, and may be critical for effective stream management and restoration. We surveyed the locations of LWJ along 18 stream segments within study areas defined by stream‐valley geomorphology. The objective of this study was to test the prediction that LWJ in this system will be aggregated in areas defined by stream‐valley geomorphology, but be randomly distributed at smaller scales. The spatial distribution of LWJ was analysed by a one‐dimensional K‐function analysis capable of detecting aggregated, random and segregated patterns at different scales. The prediction that LWJ aggregate in areas defined by stream‐valley geomorphology was supported: LWJ aggregated at scales up to several kilometres in three streams. LWJ also was segregated at smaller scales in two of these streams; this was detectable when several stream valley segments were considered together. The prediction that LWJ would be randomly distributed at smaller scales was supported at most smaller scales for most streams. In fact, 40% of individual stream valley segments contained LWJ that were randomly distributed at all scales. Twenty‐seven per cent of individual stream valley segments showed segregated LWJ distributions. Large‐scale aggregation of LWJ evidences the need to select reference reaches that encompass several geomorphic patches at the scale of the stream valley. Segregated patterns of LWJ distributions evidence opportunities to better understand the relationships between hydraulic systems, material transport dynamics and riparian forests. Copyright © 2009 John Wiley & Sons, Ltd.     

The role of riparian vegetation and woody debris in the development of macroinvertebrate assemblages in streams

Riparian vegetation development and macroinvertebrate assemblages were studied in 16 streams formed between 35 and 230 years ago, following glacial recession in Glacier Bay National Park, southeast Alaska. Riparian vegetation established most rapidly in streams where flow variation in downstream reaches was buffered by a lake. Riparian vegetation development was positively correlated with lower bank stability, but was independent of stream age. Roots and branches of riparian vegetation trailing into streams (trailing riparian habitat—TRH) were shown to be an important habitat for a number of macroinvertebrate taxa. In young and unstable streams, TRH was colonized mainly by Plecoptera whereas in more stable lake‐influenced streams Simuliidae dominated. Significant coarse woody debris (CWD) accumulations were not observed until after approximately 130 years of stream development had occurred when certain channel features, such as gravel bars, were stabilized by dead wood. Where dead wood was present, opportunistic wood taxa were abundant, even in the younger streams. However, a xylophagous species, Polypedilum fallax, was not recorded until streams were over 100 years old. Two‐way indicator species analysis (TWINSPAN) using presence/absence of macroinvertebrate taxa on TRH, initially divided streams into lake and non‐lake systems, but subsequent divisions were consistent with differences in stream age. TWINSPAN of macroinvertebrate assemblages on dead wood again highlighted differences in stream age. Canonical correspondence analysis indicated that bed stability and stream age were the most important environmental variables influencing macroinvertebrate distribution on TRH. Trailing riparian habitat was most abundant in moderately unstable streams where it facilitates invertebrate colonization. CWD contributes markedly to channel stabilization, provides habitat for invertebrate xylophages, and confers additional habitat complexity. Maximum levels of CWD are predicted to occur in non‐lake streams after approximately 300 years, but at least a further 100 years will be required in stable streams below lakes where dead wood entrainment is not enhanced by flooding, channel migration and bank undercutting. A conceptual model summarizing the role of TRH and CWD on stream development in Glacier Bay is presented. Copyright © 2005 John Wiley & Sons, Ltd.     

Fish and Macroinvertebrate Communities in Tributary Streams of Eastern Lake Erie with and without Round Gobies (Neogobius melanostomus, Pallas 1814)

Round gobies have had significant impacts on benthic fish and invertebrate communities in nearshore habitats of the Great Lakes. As round gobies have become more abundant in lake habitats, there has been an expansion of their populations into tributary streams and rivers. We compared stream invertebrate and fish communities in New York tributaries to Lake Erie with round gobies present and absent. Four of six benthic invertebrate metrics differed between streams with and without round gobies. Streams with round gobies present had reduced Shannon diversity, EPT richness, and EPT/chironomid ratios, and increased macroinvertebrate density relative to streams without round gobies, but there was no difference in non-Diptera density, or total taxa richness. None of the four fish metrics examined differed between streams with and without round gobies. However, darters occurred in all streams lacking round gobies, but did not occur in any streams with round gobies. Comparisons with historical fish and macroinvertebrate distributional data support our suspicion of goby-induced community changes. In these New York streams, round gobies seem to have had significant impacts on invertebrate communities via their consumptive behavior, whereas the impacts on fish communities are less evident. If round gobies continue to expand their distribution inland, the resultant alterations in macroinvertebrate communities may impact the suitability of tributary streams as spawning and nursery habitat for several sport fish species and for energy dynamics in tributary streams.     

Quantity,controls and functions of large woody debris in Midwestern USA streams

Large woody debris (LWD) can increase stream habitat heterogeneity by providing structure, altering flow patterns, enhancing sediment deposition, forming pools and retaining organic matter. In North America, the role of LWD has been studied extensively in streams of mature forests (e.g. Pacific Northwest), but few studies have assessed LWD in streams of younger forests (e.g. Midwestern USA). Our objectives were to: (1) quantify the volume and abundance of LWD in a set of Midwestern streams; (2) evaluate possible factors influencing LWD quantity; (3) identify the functional roles of LWD; and (4) compare LWD levels in the upper Midwest to those elsewhere in North America. In 2002 and 2003, we measured LWD and geomorphological variables in 15 low‐gradient streams draining previously logged watersheds in the Upper Peninsula of Michigan. Mean (±SE) LWD volume (0.77 ± 0.12 m³ 100 m⁻²) and abundance (33 ± 3 pieces 100 m⁻¹) were 71% and 10% lesser, respectively, than in streams of similar gradient elsewhere in North America. Channel shape (width:depth ratio) explained 30% of the variation in LWD volume (multiple stepwise regression, P = 0.015) while LWD length and length:channel width combined, explained 72% of the variation in LWD density (multiple stepwise regression, P < 0.0001). About 50% of the LWD either stored sediment or stabilized banks and 14% of the LWD formed pools, although pool density was not significantly related to LWD volume or density. LWD levels, overall, were low in upper Midwestern streams, but the relative importance of that LWD to ecosystem function may be magnified in these wood‐poor systems. Copyright © 2006 John Wiley & Sons, Ltd.     

Massive Growth of the Invasive Algae Didymosphenia Geminata Associated with Discharges from a Mountain Reservoir Alters the Taxonomic and Functional Structure of Macroinvertebrate Community

The objective of this paper is to determine the alteration of the taxonomic composition and functional structure of macroinvertebrate community associated with a massive growth of the invasive algae Didymosphenia geminata downstream of a mountain reservoir (Pajares Reservoir, La Rioja, Northern Spain). As the massive growth of the alga disappears a few kilometres downstream of the reservoir associated with the input of nutrients from a nearby village sewage, we may compare the community composition between nine stations in three different conditions: three stations heavily affected by the presence of D. geminata, three further downstream stations without the algal massive growth but affected by river regulation and three control stations (unregulated and without the algae). Results show a significant disturbance of the composition and structure of macroinvertebrate community in sites affected by the stream flow regulation downstream of the dam compared with unregulated streams, but the alterations are more dramatic in the area where the growth of D. geminata is massive because of the total substrate occupation by the algal filaments. Scrapers and others invertebrates living on the coarse substrate are especially affected at such sites. Moreover, an important increase in the relative abundance of chironomids is associated with the algal massive growth, especially in case of Eukiefferiella devonica and Cricotopus spp., reducing the assemblage diversity and leading to the taxonomic and functional homogenization of the community. Changes in the reservoir management (such as releasing the water from surface rather than from the hypolimnion) may be useful to control the massive growth of D. geminata and thus reducing the effects of river regulation on macroinvertebrate assemblage composition. Copyright © 2014 John Wiley & Sons, Ltd.     

Periphyton and invertebrate response to wood placement in large pacific coastal rivers

Wood abundance in aquatic systems has been dramatically reduced compared to historical levels due to anthropogenic activities that led to wood removal and stream simplification. As a result, reintroduction of wood to aquatic systems is now a widely used and relatively well‐studied restoration technique for increasing habitat complexity. Although stream periphyton (biofilm) and invertebrates serve as food sources for a variety of predators including fish, birds and bats, data on how lower trophic levels respond to wood placement are relatively scarce. The purpose of this study was to test the hypothesis that periphyton biomass and aquatic invertebrate density were higher on Engineered Log Jams (ELJs) than on inorganic substrates in two large Pacific Northwest river systems. Among years and rivers, periphyton biomass and invertebrate densities were significantly higher on ELJs than on cobbles within the same reach. Invertebrate communities on ELJs were dominated by meiofauna (<500 µm), whereas cobbles were dominated by larger chironomids. We attribute these trophic level differences to substrate type, as we did not detect taxonomic differences between cobbles in reaches with and without ELJs. We show that adding wood to reaches with little or no naturally occurring wood increased overall habitat surface area and thereby the potential for increased productivity relative to reaches with low levels of wood. Finally, wood supports a unique community of invertebrates that are often overlooked in lotic system studies but may be contributing substantially to overall biological diversity. Published in 2009 by John Wiley & Sons, Ltd.     

赣江干流底栖动物群落结构与环境因素的关系

底栖动物是河流水生态系统的重要组成部分,对水环境的变化极其敏感.为分析赣江干流底栖动物群落结构特征及其与环境因素的关系,本研究于2018年8月、2019年1月及4月在赣江干流布设12个采样点进行底栖动物调查.赣江干流共检出底栖动物3门6纲24种属,上游的优势种分别为苏氏尾鳃蚓和铜锈环棱螺,中游的优势种为铜锈环棱螺和河蚬...     

Spatial and seasonal variations in phytoplankton community structure in alkaline–saline Lake Nakuru,Kenya

Spatial and seasonal variations of phytoplankton, expressed in terms of species composition, cell density, biovolumes and biomass, collected at 10 sampling sites in alkaline–saline Lake Nakuru, Kenya, were investigated monthly from March 2004 to February 2005, in relation to selected physical and chemical water quality parameters. A total of eight species, belonging to five genera and three classes, were recorded. The Cyanophyceae comprised the bulk of the phytoplankton, followed by Euglenophyceae, while Bacillariophyceae were the least abundant. Arthrospira fusiformis was the most dominant species, in terms of density, among the Cyanophyceae, while Euglena spp. and Navicula elkabs dominated the Euglenophyceae and Bacillariophyceae density, respectively. Seasonal variations in phytoplankton species composition, density and biomass were significant (P < 0.05) with minimum cell density and biomass occurring during the dry season, and being maximum following the end of the two rainy seasons from May to November 2004, suggesting the possible influence of various environmental factors on the lake. Sampling sites located close to the inlets of inflowing rivers exhibited significantly (P < 0.05) higher phytoplankton cell density and biomass than those by the inshore sites. Soluble reactive phosphorus, ammonia‐nitrogen, conductivity and total alkalinity accounted for most of the variations in the cell densities of phytoplankton species.     

Abundance and function of large woody debris in small,headwater streams in the Rocky Mountain foothills of Alberta,Canada

Large woody debris (LWD) significantly influences the structure and function of small headwater streams. However, what it contributes to geomorphic function depends on where it is located relative to the stream channel. We quantified LWD abundance and tested for associations among decay, position, orientation and function classes in 21 streams near Hinton, Alberta, Canada. LWD was more frequent (64.0 ± 3.3 LWD 100 m^?1) in streams in the Alberta foothills than it was in small streams in mountain, coastal, broadleaf deciduous and boreal forests, likely due to the narrow channel widths and low capacity of our study streams to transport logs downstream. LWD volumes were greater in coastal streams than in the Alberta foothills, likely due to differing tree sizes and decay rates. LWD morphology changed significantly as logs decayed and transitioned to different position and orientation classes. LWD in decay classes I and II were longest, most commonly in the bridge and partial bridge position classes, oriented perpendicular to stream flow, suspended above the channel and contributing least to stream geomorphic functions. LWD length and volume (but not diameter) decreased as decay advanced, making logs less stable. LWD in decay classes III and IV were strongly associated with partially bridged, loose, and buried position classes. They were more commonly diagonal or parallel to stream flow and contributed to bank stability, sediment retention, debris jams and riffle and pool formations. These results have been integrated into a conceptual model of LWD dynamics that provides a framework for future research on the mechanisms and rates of LWD recruitment, decay, transport and function. Copyright © 2010 John Wiley & Sons, Ltd.     

Influence of dam operation on mayfly assemblage structure and life histories in two south-eastern Australian streams

The mayfly fauna, and in particular the life histories of two mayflies, Coloburiscoides sp. and Baetis sp. 3, was studied in two nearby streams located in the headwaters of the River Murray, SE Australia. The Mitta Mitta River is regulated by the Dartmouth Dam which releases cold water in summer for irrigation. Snowy Creek is a tributary of the Mitta Mitta River with natural flow and temperature regimes. The structure of the mayfly assemblage differs in the two streams. In the regulated Mitta Mitta there are 11 species, of which, caenids (Tasmanocaenis tonnoiri and River Murray sp. C), Coloburiscoides sp. and Baetis sp. 3 dominate. Snowy Creek, with a richer assemblage of 17 species, was dominated by Coloburiscoides sp., Baetis sp. 3 and two Austrophlebioides species. Monthly collections of mayfly nymphs and adults between September 1987 and August 1988, in both streams, allowed evaluation of possible life history changes in relation to dam operation. Coloburiscoides sp. and Baetis sp. 3 had synchronous life histories at both regulated and unregulated sites. Coloburiscoides appeared to be univoltine, and Baetis polyvoltine. At the regulated site, nymphal abundance in both Coloburiscoides and Baetis declined during the summer release, which coincided with the beginning of nymphal recruitment and appeared to delay nymphal hatching in Coloburiscoides. © 1998 John Wiley & Sons, Ltd.     

Progressive changes in phytoplankton community structure in urbanized lowland river floodplains—a multivariate approach

Phytoplankton communities along the river Yamuna in Delhi stretch and its associated floodplain lakes showed considerable spatio‐temporal variations. Most of the species identified were cosmopolitan and typical of highly polluted rivers in tropical ecosystems. All the groups of phytoplankton with predominance of Cyanophyceae and some species of Chlorophyceae were distributed within the river stretch though with varying diversity and density. Relatively cleaner sites supported larger phytoplankton assemblages compared to those subjected to sewage outfalls and industrial effluents. Species elimination was observed mainly in the mid‐stretch and downstream of Okhla subjected to high loads of pollution. Co‐inertia analysis indicated significant co‐structures between water quality and species richness and density indicating water quality as the governing factor for phytoplankton distributions in the river stretch. Floodplain plays an important role in regenerating water quality thereby enhancing species richness and density. Floods play an important role in seasonal dynamics through dilution effects and promoting connectivity between river channel and floodplain lakes thereby facilitating species exchanges. Copyright © 2008 John Wiley & Sons, Ltd.     

Experimental effects of sediment deposition on the structure and function of macroinvertebrate assemblages in temperate streams

Fine sediment in streams and rivers is one of the most globally widespread of all freshwater pollutants. However, the ecological implications are still poorly quantified, and field experiments to assess likely functional and structural effects are scarce. We assessed the response of stream invertebrates to fine sediment (i.e. inert sand) added to trays (n = 65) containing otherwise natural substrata over a three‐week period in three replicate streams in the Usk catchment, Wales. Sediment addition to 0.6–18 kg m^?2 affected both the structure and functional composition of invertebrate assemblages while also reducing overall abundance and in some common species (Baetis rhodani, Ecdyonurus sp. and Leuctra geniculata). Sediment also reduced richness and overall trait diversity (TD), while different life‐history traits were either favoured (polivoltinism, tegumental respiration and burrowing behaviour) or disfavoured (swimmers, attached taxa, gill respiration). Moreover, sediments appeared to promote a nested subset pattern in species composition, with generalists favoured at the expense of specialists either through exclusion or impaired colonization. Effects were due largely to the loss of five taxa that contributed to the significant nestedness across the sand gradient: B. rhodani, Ecdyonurus sp., Leuctra geniculata, Simuliidae and Ephemerella ignita. This short‐term experiment supports recent surveys in indicating how sedimentation can change the structural and functional composition of stream invertebrate assemblages even at low to moderate rates of deposition. In revealing direct effects on trait adversity, trait representation and nestedness, the data are also consistent with survey data in indicating that sediments have potentially important ramifications for conservation by removing organisms systematically according to life‐history features. Copyright © 2010 John Wiley & Sons, Ltd.     

Submerged aquatic vegetation cover and complexity drive crustacean zooplankton community structure in a large fluvial lake: An in situ approach

Submerged aquatic vegetation (SAV) is considered an important driver of the zooplankton community, owing to the refuge offered by its structural complexity. However, non-destructive in situ approaches to assess quantitatively the features of SAV beds and their effects on zooplankton community are still lacking. This study aims to: 1) estimate SAV cover and complexity using subaquatic upward photographs (SUP) and 2) analyse the relationship between SAV variables and crustacean zooplankton composition and functional diversity (FD). SAV biomass and zooplankton were sampled at 52 stations in a large fluvial lake. Two metrics based on SUP were used to quantify SAV cover and complexity: 1) the percentage of the underwater landscape occupied by SAV (PLAND: SAV cover), and 2) its perimeter-area fractal dimension (PAFRAC: SAV complexity). Zooplankton composition and functional diversity were estimated based on crustacean species assemblages and functional traits. We used linear models to describe the relationships between SAV indices, environmental variables and zooplankton abundance, biomass and FD. SUP was an effective method to estimate in situ SAV cover and complexity. PLAND and PAFRAC were positively related to SAV biomass and zooplankton abundance, yielding a non-destructive assessment of the SAV-zooplankton relationships. Our study partially supports the habitat complexity-ecological niche availability hypothesis, as SAV cover and complexity influenced zooplankton functional groups and diversity indices. However, water transparency and depth also had important effects in interaction with PLAND and PAFRAC, and it remains difficult to fully disentangle the effects of SAV complexity from SAV cover on crustacean zooplankton community structure.     

岗南水库浮游植物群落结构与水质评价

通过对岗南水库中浮游植物数量、种群结构的分析以及其叶绿素含量的测定,对水库水体的营养程度、出现富营养化趋势进行分析,以期为保护生态环境、治理环境污染、合理开发水库水资源提供科学依据。     

Variations in zooplankton community structure and water quality conditions in three habitat types in northern Lake Victoria

Lake Victoria is vulnerable to increasing eutrophication, which has become manifested in ecological changes not yet fully understood. From October 2009 to January 2010, the influence of water quality on zooplankton community structure in three habitats in northern Lake Victoria, including sewage lagoons at the lake shores, Napoleon Gulf (NG) and the interface between the lake and the Nile River (also known as Source of the Nile River), was examined. Selected physico‐chemical parameters (dissolved oxygen concentration; water temperature; electrical conductivity; water depth) were measured in‐situ, while water samples were collected for chlorophyll‐a determinations. Zooplankton was sampled with conical plankton net (mesh size 60 μm; 0.25‐m mouth diameter). The NG and Source of the River Nile (SN) sampling sites exhibited significantly higher species richness, relative to the Sewage Lagoons (SL) site (F_2,69 = 68.533; P < 0.05). Higher mean densities and dry biomass of zooplankton was generally a characteristic of the SL site (8715 ± 3241 ind L^?1; 1862 ± 451 μg L^?1), compared to the NG (119 ± 24 ind L^?1; 53 ± 8 μg L^?1) and SN sites (151 ± 26 ind L^?1; 58 ± 9 μg L^?1). Copepoda constituted a high numerical composition of the zooplankton at the NG and SN sites (>90% for both sites), while Rotifera dominated the zooplankton community at the SL site (97%). The mean values (±SE) of soluble reactive phosphorus (4060.7 ± 776.6 μg L^?1) and nitrate–nitrogen (2121.7 ± 355.5 μg L^?1) were much higher for the SL site, compared with the SN (8.2 ± 1.1 μg L^?1; 28.6 ± 5.3 μg L^?1, respectively), and NG site (7.8 ± 0.8 μg L^?1; 32.7 ± 5.4 μg L^?1, respectively). This study indicated the nutrient‐rich conditions observed at the SL site suppress the zooplankton species diversity, but favour species‐specific abundance and biomass. These study results indicate the zooplankton community structure can be used as a biological indicator of water quality in the Lake Victoria region.     

Crayfish assemblages correlate with dam-induced effects on abiotic factors and predatory fish assemblages in Alabama streams

Stream faunal assemblage structure is tied closely to hydrology and associated physiochemical properties. By altering natural flows, dams and their impoundments impact faunal assemblages over long distances. Although numerous studies have assessed the effect of dams on stream fauna, information is lacking for crayfishes. In this study, we characterized the effects of relatively large storage dams on crayfish assemblage structures. Over 2 years, we sampled three impounded and two unimpounded streams across two drainages in Alabama, United States, to identify biotic and abiotic factors correlated with crayfish assemblage metrics. Compared to impounded streams, unimpounded streams had greater habitat complexity (e.g., aquatic vegetation and woody debris), fewer predator fishes, lower minimum temperatures, and more variable discharges. These characteristics correlated with a higher density and diversity of crayfishes and smaller adults in impounded compared to unimpounded streams. Crayfish species assemblages differed between drainages, as did the biotic and abiotic factors affecting crayfish assemblages in each drainage, suggesting that these factors were species-specific in their effects. Additionally, analysis of land uses suggested that factors other than dams may have also contributed to the observed differences in assemblage structures between impounded and unimpounded streams. For instance, in the more urbanized drainage, crayfish assemblages were more similar between up and downstream sections in all streams, regardless of impoundment. Our results indicate that large dams alter stream crayfish assemblage structure, with potentially cascading effects in trophic and organic matter dynamics both up and downstream.     

南水北调中线水源区浮游植物群落结构及其生物多样性

为探究南水北调中线水源区丹江口水库浮游植物群落结构变化及其生物多样性,于 2014—2015 年对丹江口水库进行为期 1 年的调查和分析。发现浮游植物共 8 门 76 属 101 种,其中,绿藻门、蓝藻门及硅藻门占总种数90.10%,绿藻门种类数最多（45 种）,其次是蓝藻门（26 种）和硅藻门（20 种）。浮游植物群落结构随季节变化有所不同：夏秋季节生物量明显高于冬春季节;优势种在冬季以颗粒直链藻、颗粒直链藻极狭变种、铜绿微囊藻和小环藻为主,春季以球衣藻、薄甲藻属及小环藻为主,夏季以简单颤藻、单胞衣藻原变种和球衣藻为主,秋季以类颤藻鱼腥藻、简单颤藻、球衣藻和小环藻为主。应用 Shannon-Wiener 多样性指数 H′、Pielou 均匀度指数 J′、Margalef丰富度指数 Dm评价水质结果表明：丹江口水库夏秋季水体营养化程度更高。典型对应分析表明：水温、透明度、总氮、总磷等是影响浮游植物群落结构的主要环境因子,夏秋季受温度影响蓝藻、绿藻数量逐渐增多,一定程度上增加了受水区生态变化风险。本研究可为南水北调中线水源区丹江口水库生态环境变化及生物迁移风险提供数据支持。