Hydrophyte Species Research Articles

Occurrence and diversity of stem nodulation in Aeschynomene and Sesbania legumes from wetlands of Madagascar

Legumes have the ability to establish a nitrogen-fixing symbiosis with soil rhizobia that they house in specific organs, the nodules. In most rhizobium-legume interactions, nodulation occurs on the root. However, certain tropical legumes growing in wetlands possess a unique trait: the capacity to form rhizobia-harbouring nodules on the stem. Despite the originality of the stem nodulation process, its occurrence and diversity in waterlogging-tolerant legumes remains underexplored, impeding a comprehensive analysis of its genetics and biology. Here, we aimed at filling this gap by surveying stem nodulation in legume species-rich wetlands of Madagascar. Stem nodulation was readily observed in eight hydrophytic species of the legume genera, Aeschynomene and Sesbania, for which significant variations in stem nodule density and morphology was documented. Among these species, A. evenia, which is used as genetic model to study the rhizobial symbiosis, was found to be frequently stem-nodulated. Two other Aeschynomene species, A. cristata and A. uniflora, were evidenced to display a profuse stem-nodulation as occurs in S. rostrata. These findings extend our knowledge on legumes species that are endowed with stem nodulation and further indicate that A. evenia, A. cristata, A. uniflora and S. rostrata are of special interest for the study of stem nodulation. As such, these legume species represent opportunities to investigate different modalities of the nitrogen-fixing symbiosis and this knowledge could provide cues for the engineering of nitrogen-fixation in non-legume crops.

Measurements of Carbon Assimilation in Aquatic Systems.

The recent development of an infrared gas analyzer capable of making carbon dioxide flux measurements from aquatic samples has enabled a new sphere of photosynthesis research. This study details key photosynthesis measurements on four aquatic and hydrophytic species, diverse in their morphology, physiology, and habitat. This guide specifies the methods and procedures needed to make reliable and accurate gas exchange measurements, with examples of data correction and presentation.

Beyond taxonomic diversity patterns - investigating how α and β components of macrophyte functional diversity respond to environmental gradients in lotic ecosystems of Greece.

In addition to quantifying the taxonomic diversity of aquatic communities, understanding the patterns of alpha functional diversity (α-diversity) and exploring changes in functional dissimilarity (β-diversity) can improve our understanding on how ecosystems respond to environmental changes. In this study, we quantified functional alpha (α) and beta (β) diversity of macrophytic assemblages from river sites in Greece and then, examined relationships with water quality parameters and hydromorphological factors. We assigned 6 traits (Ellenberg nutrients indicator, Ellenberg light indicator, growth form, leaf size, leaf type, fruit size) to a total of 36 hydrophyte species and calculated three indices of functional diversity (functional richness, functional dispersion and functional evenness). We also estimated the total β-functional diversity and its' main components, turnover and nestedness. To assess the effects of water quality (including physical and chemical variables) we used Generalized Additive Models (GAM) for alpha functional diversity indices and Generalized Dissimilarity Models (GDM) for beta functional diversity. We performed Kruskal-Wallis tests and permutational multivariate analysis of variance (PERMANOVA) to search for significant variations of α- and β-diversity among the hydromorphological factors. Our results showed that macrophyte growth form and light preference were important trait characteristics that explained a large share of the total variance of functional composition. We also found relatively low taxonomic and functional richness, whereas taxonomic and functional dissimilarity were mostly attributed to species turnover, which expresses the changes in taxonomic and functional composition. We found significant relationships between functional dispersion and functional evenness with pH and oxygen saturation, whereas functional dissimilarity was driven only by geographic distance, although the GDM explained a small portion of the total variance. Functional richness, dispersion and evenness were significantly higher at systems with fine substrates and deep waters with low or high flow compared to systems with coarser substrates and riffle habitats. We also found significant variation in functional dissimilarity among the hydromorphological factors, although much of the total variance remained unexplained. Overall, our study highlights the importance of considering the functional diversity of aquatic plant assemblages within the frame of freshwater monitoring and conservation plans.

Relationships between Environmental Factors and Functional Traits of Macrophyte Assemblages in Running Waters of Greece

The analysis of plant trait composition has raised significant interest among freshwater ecologists as a complementary approach for assessing the effects of environmental change on ecosystem functions. In this study, we investigated patterns of functional traits of the aquatic macrophyte assemblages of 74 lotic ecosystems of Greece, and we identified associations between species traits and environmental variables (hydromorphological and physicochemical parameters) through testing the hypothesis that the environmental features determine the spatial structure of traits. We allocated 12 traits to a total of 39 hydrophyte species, and we conducted RLQ and fourth corner analysis to explore relationships between species, trait composition, and environmental gradients. Based on the results of the RLQ, a hierarchical cluster analysis was conducted to identify groups of plants that share common trait characteristics. Plants were discriminated into five discrete groups based mostly on their life form (e.g., free-floating, rooted submerged etc.) and their ecological preference for nitrogen levels. Hydromorphological parameters had a higher contribution than physicochemical variables in explaining the total variance of the trait data, with water abstraction, channel substrate, and hydrologic alteration being the most important. Our analysis did not reveal significant bivariate relationships between single traits and environmental parameters, although the five groups of macrophyte assemblages appeared to associate with certain environmental gradients. Free-floating and emergent plants were related to higher concentrations of nutrients, whereas rooted submerged plants were related to higher oxygen concentration and increased pH. In addition, free-floating plants were highly associated with metrics of hydromorphological change. Our findings showed clear discrimination of macrophytes based on their functional composition and association of traits with environmental gradients. Thus, further research could explore whether macrophyte functional groups can serve as indicators of environmental change and the overall ecosystem health.

Species Diversity and Distribution of Macrophytes in Different Wetland Ecosystems

Wetlands are vital and dynamic components of the global ecosystem, providing a wide range of ecosystem services such as water control and biodiversity. During 2015–2019, plant diversity and distribution of wetlands were studied in forty areas of the Mardan division, Khyber Pakhtunkhwa, Pakistan. A total of 282 vascular wetland plant species were identified, divided into 192 genera and 73 families. Poaceae, with 41 species, is the most diverse family of wetland plants, followed by Asteraceae, with 26 species. In the present study, wetland plants are classified based on the Cook classification system. It is interesting to note that all the life forms were present in the study area except Plankton. Helophyte life form was represented by the highest number of plants with 177 plants and 62.5 percent of total wetland plants, followed by Tenagophyte with 42 plant species (14.8%) and Hyperhydate with 27 plant species (9.5%). Based on the distribution pattern of 282 species in 40 wetland sites, the most common plant species found was Euphorbia helioscopia, recorded from 36 locations, followed by Cynodon dactylon which was found in 32 locations. In Mardan division, the Gulshan Abad Khuwar had the highest number of species occurrences (83 species) accounting for 32% of all species, followed by Alo Khwar (59 species, 23%) and Hathian Khwar (50 species, 19%). The current work presents a comprehensive and field-based detailed survey of wetland plant distribution in this region, filling knowledge gaps in the Himalayas in particular, and having broader implications for wetland management policy and practice. Unfortunately, wetlands of the research area are facing high pressure due to an increase in human population, overgrazing, deforestation, construction of buildings and roads. The filling up of these water bodies is resulting in the loss of hydrophytic species diversity. Therefore, these wetlands need proper attention and effective protection from anthropogenic disturbances.

Resiliency and Recovery of Aquatic Vegetation Following Scouring Floods in Two First-Magnitude Springs, Missouri, USA

This study quantifies the loss of vegetative cover in Alley and Big springs, Missouri, following a catastrophic, ‘100 year’ flood, and documents their subsequent recovery. Foliar cover of aquatic vegetation was measured in each spring along six transects, each having three sample cells (1 m2, N = 18). Species diversity analyses included taxa richness, Shannon’s diversity index, and Simpson’s diversity index, which were expressed as the effective number of species (S, He, and De). Species metrics were calculated as individual species frequency (ISF), percent foliar cover (PFC), and species importance value (SIV). Post-flood community diversity metrics (S, He, and De) for the springs were largely not significant for most measures (Epps–Singleton test p > 0.05). This suggests that they may not be sufficiently sensitive for detecting change in springs when the sample size is small. Bare substrate increased significantly at Big Spring post-flood (mean = 87.50%; Epps–Singleton test, p = 0.02), but not at Alley Spring (Epps–Singleton test, p = 0.42). Various alga taxa generally exhibited increased frequency and abundance following the flood, which is reflected in their overall higher SIVs. Most hydrophyte species at Alley Spring showed a marked decline compared to the pre-flood average, only to substantially increase in the last year of sampling, thus maintaining their approximate species important values relative to their pre-flood averages. Several hydrophyte species at Big Spring showed significant decreases (Epps–Singleton test p < 0.05) in their respective community metrics, and recovery had not returned to pre-flood levels on the last sampling date. This study showed that loss and recovery of aquatic vegetation in high-magnitude Ozark springs following flooding are a function of flood intensity as well as substrate size and retention, and proximity to the receiving stream.

Riparian vegetation composition and diversity shows resilience following cessation of livestock grazing in northeastern Oregon, USA.

Riparian ecosystem restoration has been accomplished through exclusion of livestock using corridor fencing along hundreds of kilometers of streams in the western United States, for the benefit of riparian-obligate wildlife and endangered fishes. Yet, there are limited scientific studies that have evaluated more than short-term shifts in vegetation composition and diversity at a single location or handful of locations following grazing. We sampled riparian vegetation composition along 11-paired grazed and ungrazed (exclosed) stream reaches in northeastern Oregon. Exclosure ages ranged from 2 to >30 years and grazing treatments varied from light grazing every one out of three years to heavy season-long grazing. Species richness and diversity was higher in the ungrazed reaches (p = 0.002). The abundance of native sedges (Carex spp.) and broad-leaved forbs were also significantly (p ≤ 0.05) greater in ungrazed areas. In contrast, exotic species adapted to grazing such as Poa pratensis and Trifolium repens were more abundant in grazed stream reaches. The prevalence of hydrophytic species significantly increased (p ≤ 0.01) in ungrazed reaches, (based on wetland species indicator scores), indicating that wetland-dominated communities within the ungrazed stream reaches were replacing ones adapted to drier environments. The increased abundance of facultative and wetland-obligate species in ungrazed reaches compared to grazed reaches suggests that livestock grazing exacerbates those climate change effects also leading to warmer and drier conditions. Further, riparian-obligate shrub cover along the streambank was higher in 7 of 8 exclosures that were older than 5 years (p = 0.05). As a restoration approach, the inherent resilience of riparian ecosystems exhibited in ungrazed riparian zones suggest positive feedbacks to other beneficial ecosystem processes such as increased species and habitat diversity, increased carbon sequestration, enhanced allochthonous inputs and greater sediment retention, that would affect the aquatic and terrestrial biota, water quality, and stream morphology.

Survey on aquatic macrophytes and physico-chemical quality of water from Satla Beel of Barishal district, Bangladesh

Preliminary taxonomic survey on aquatic plants of Satla Beel was conducted from May 2021 to August 2021. A complete of thirty aquatic plant species under twenty families was recorded from Satla Beel. Ecological habitats of hydrophyte species showed variations. The Study was conducted to estimate the diversity of aquatic macrophytes and the physico-chemical parameters of water from four different locations in study area. The chosen parameters were water depth, electric conductivity, pH, salinity, total dissolved solid (TDS), phosphate and dissolved oxygen (DO). Water depth fluctuated from 152 cm to 213 cm, conductivities ranged from 0.23 ms/cm to 0.29 ms/cm, pH scale ranged from 6.60 to 7.60, salinity ranged from 132 to 148 ppm and TDS from 349 ppm to 393 ppm. Mean DO and phosphate were recorded as 3.28 mg/L and 762.25 μg/L, respectively.

Hitherto Unrecorded Hydrophytes of Nal Sarovar Bird Sanctuary (A Ramsar Site)

Nal Sarovar Sanctuary and the Ramsar Site in Gujarat is known for its diversity and abundance of migratory and resident-migratory waterbirds. Though it is also rich in hydrophytic and halophytic vegetation, relatively limited research work has been done on them till date. Seasonal monitoring of this wetland was carried out from 2016 to 2019 with habitat based stratified random sampling approach. During the study, a total of 19 hydrophyte species were recorded in 2019 of which 4 hydrophytes were never reported earlier from this wetland-based sanctuary. The four hydrophytes were Ceratophyllum demersum (a free-floating submerged hydrophyte), Utricularia stellaris (rooted submerged hydrophyte), Ottelia alismoides (a rooted submerged hydrophyte) and Limnophyton obtusifolum (an emergent hydrophyte). They were recorded in shallow water marshy habitats of the Nal Sarovar Sanctuary and Ramsar Site. They were found in association with other hydrophytes like Chara sp., Ipomoea aquatica and Nymphaea nouchali. Per cent cover value (determined using Daubenmire frame) for Ceratophyllum demersum and Utricularia stellaris was 1% each. On the other hand, Ottellia alismoides and Limnophyton obtusifolum were found to have 4% and 2% canopy coverage respectively at the site where they were recorded. They were recorded at a depth of about 80-100 cm and having turbidity in the range of 0.1 to 0.6 NTU and salinity ranging from 0.8 to 2 ppt.

Effects of the Climate Change on Peripheral Populations of Hydrophytes: A Sensitivity Analysis for European Plant Species Based on Climate Preferences

Biogeographical theory suggests that widespread retractions of species’ rear edges are expected due to anthropogenic climate change, affecting in a particularly intense way those linked to fragile habitats, such as species’ rear edges closely dependent on specific water conditions. In this way, this paper studies the potential effects of anthropogenic climate change on distribution patterns of threatened rear edge populations of five European hydrophyte plants distributed in the Iberian Peninsula. We explored (i) whether these populations occur at the limit of the species’ climatic tolerance, (ii) we quantified their geographic patterns of vulnerability to climate change, and in addition, (iii) we identified in a spatially explicit way whether these threatened populations occur in vulnerable environments to climate change. To do this, we simulated the climatic niche of five hydrophyte species using an ecological modelling approach based on occurrences and a set of readily available climatic data. Our results show that the Iberian populations studied tended to occur in less suitable environments relative to each of the species’ optimal climates. This result suggests a plausible explanation for the current degree of stagnancy or regression experienced by these populations which showed high sensitivity and thus vulnerability to thermal extremes and high seasonality of wet and temperature. Climatic predictions for 2050 displayed that most of the examined populations will tend to occur in situations of environmental risk in the Iberian Peninsula. This result suggests that the actions aimed at the conservation of these populations should be prioritized in the geographic locations in which vulnerability is greatest.

Plant Community Response to Hydrologic Restoration in the Great Dismal Swamp

Peatlands in the mid-Atlantic outer coastal plain region contain obligate hydrophyte species which were harvested and replaced by facultative tree species. The Great Dismal Swamp was drained from the colonial era until 1974, when water levels were partially restored. In September 2013, further restoration consisting of two large weirs followed extensive peat-burning fires. This study evaluated depth-to-water-table and vegetation structure both prior to and following weir operation. Wells were installed and depth-to-water-table was recorded continuously from 2013 to 2015 within six of the 15 forested stands where vegetation species dominance was quantified for tree, shrub, herb, and vine strata. Following weir installation in 2013, water tables rose an average of 28.08 cm in 2014 and 32.69 cm in 2015, during the June–July peak of the growing season. Most water levels were too low to meet the federal regulatory indicator of wetland hydrology or the seasonally flooded, saturated hydrologic regime typical of peatlands. After restoration, species dominance and frequency, as well as metrics based on hydrophyte dominance and floristic quality in study plots, were unchanged. Ordinations detected no directional shift in plant community composition among pre- and post-weir periods. Although insufficient time may have passed for shifts in plant communities, additional increases in water level above those reported here appear necessary to restore a pre-disturbance hydrologic regime and plant community structure. However, above some threshold water level, planted trees will exhibit increased mortality and limit reestablishment.

Palustrine forested wetland vegetation communities change across an elevation gradient, Washington State, USA.

BackgroundForested wetlands support distinct vegetation and hydrology relative to upland forests and shrub-dominated or open water wetlands. Although forested wetland plant communities comprise unique habitats, these ecosystems’ community structure is not well documented in the U.S. Pacific Northwest. Here I surveyed forested wetland vegetation to identify changes in community composition and structure across an elevation gradient that corresponds to flooding stress, asking: (1) How do forested wetland plant communities change across an elevation gradient that corresponds to flood frequency and duration? (2) At what relative elevations do different plant species occur within a wetland?MethodsI measured overstory tree basal area and structure and understory vascular plant composition in three zones: wetland buffers (WB) adjacent to the wetland, an upper wetland (UW) extent, and a lower wetland (LW) extent, surveying individual trees’ root collar elevation relative to the wetland ordinary high-water mark (OHWM). I estimated understory plant species abundance in sub-plots and surveyed these plots’ height above the OHWM. I used non-metric multidimensional scaling ordination to identify patterns in vegetation communities relative to wetland elevation, and tested for compositional differences between the WB, UW and LW zones using PERMANOVA. I calculated overstory and understory indicator species for each wetland zone using indicator species analysis.ResultsForest overstory composition changed across the elevation gradient, with broad-leaved trees occupying a distinct hydrologic niche in low-lying areas close to the OHWM. Conifer species occurred higher above the OHWM on drier microsites. Pseudotsuga menziesii (mean elevation = 0.881 m) and Tsuga heterophylla (mean elevation = 1.737 m) were overstory indicator species of the WB, while Fraxinus latifolia (mean elevation = 0.005 m) was an overstory indicator for the upper and lower wetland. Understory vegetation differed between zones and lower zones’ indicator species were generally hydrophytic species with adaptations that allow them to tolerate flooding stress at lower elevations. Average elevations above the OHWM are reported for 19 overstory trees and 61 understory plant species. By quantifying forested wetland plant species’ affinities for different habitats across an inundation gradient, this study illustrates how rarely flooded, forested WB vegetation differs from frequently flooded, LW vegetation. Because common management applications, like restoring forested wetlands and managing wetland responses to forest harvest, are both predicated upon understanding how vegetation relates to hydrology, these data on where different species might establish and persist along an inundation gradient may be useful in planning for anticipated forested wetland responses to restoration and disturbance.

Environmental determinants of lake macrophyte communities in Baikal Siberia

We investigated whether environmental filtering or dispersal-related factors mostly drive helophyte and hydrophyte species richness and community composition in 93 lakes situated in Baikal Siberia. Using partial linear regression and partial redundancy analysis, we studied (1) what are the relative roles of environmental variables, dispersal variables, spatial processes and region identity (i.e., river basins) in explaining variation in the species richness and species composition of helophytes and hydrophytes across 93 Siberian lakes, and (2) what are the differences in the most important explanatory variables driving community variation in helophytes versus hydrophytes? We found that, for both species richness and species composition, environmental variables clearly explained most variation for both plant groups, followed by region identity and dispersal-related variables. Spatial variables were significant only for the species composition of hydrophytes. Nutrient-salinity index, a proxy for habitat trophic-salinity status, was by far the most significant environmental determinant of helophytes and hydrophytes. Our results indicate that environmental factors explained the most variation in both species richness and species composition of helophytes and hydrophytes. Nevertheless, dispersal-related variables (i.e. spatial and dispersal) were also influential but less important than environmental factors. Furthermore, the dispersal-related variables were more important for hydrophytes than for helophytes. Most brackish permanent lakes were mostly located in the steppe biomes of southern Transbaikalia. This characteristic along with the oldest age, the largest distances to both river and settlements and the lowest temperatures in the study region distinguished them from freshwater, drained and more nutrient-rich floodplain lakes.

Effect of Soil Transplantation to Abandoned Paddy Field on the Conservation of Threatened Hydrophyte Species

Threatened or near threatened hydrophytes, Ottelia alismoides, Monochoria korsakowii, Najas graminea, Najas minor and Chara braunii, appeared in an inundated paddy field after the 2011 Tohoku-oki Tsunami in Japan. Due to the reconstruction of roads and agricultural restoration efforts implemented following the disaster, the top soil of the paddy field was transplanted to another abandoned paddy field in 2014 to avoid extirpation of the aforementioned species. We then conducted vegetation surveys in July and September from 2014 to 2016. Monochoria korsakowii appeared at the transplantation site from 2014 to 2016, forming a large community in 2016. The volume of this species was significantly higher than that in July 2014 and 2015. Although Ottelia alismoides and Chara braunii appeared in 2014, they were not observed in 2015. Najas graminea and Najas minor were not observed during the vegetation survey, and Salvinia natans and Alisma plantago-aquatica newly appeared at the transplantation site. Our findings suggest that transplantation of surface soil and the seed bank therein to an abandoned paddy field is well suited for the conservation of hygrophytes such as Monochoria korsakowii, Ottelia alismoides and Chara braunii. Preventing disturbances that suppress the growth of herbaceous perennial plants is considered necessary for maintaining the habitats of threatened plant species.

Remediation of industrial wastewater using four hydrophyte species: A comparison of individual (pot experiments) and mix plants (constructed wetland)

Remediation and management of industrial wastewater (IWW) using hydrophytes act as one of the cost effective and environmentally friendly technologies. The present study was conducted to assess the role and efficiency of selected four hydrophyte species through constructed wetland (CW) for the removal of heavy metals (HMs) from IWW. Samples of wastewater (WW) were collected from the main drain of Hayatabad Industrial Estate (Peshawar, Pakistan) and analysed for HMs like cadmium (Cd), copper (Cu) and lead (Pb) along with basic physicochemical parameters like pH, electric conductivity (EC), total suspended solids (TSS), total dissolved solids (TDS), dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), dissolved organic carbon (DOC) through standard analytical methods. Four hydrophytes species such as Typha latifolia (cattail), Eichhornia crassipes (water hyacinth), Lemna gibba (duck weed) and Pistia stratiotes (water cabbage) were transplanted into CW (mix cultivation). Each selected species was also cultivated in individual pots for investigating their efficiency to remove HMs. The Cd, Cu and Pb removal efficiency of CW was recorded as 39.5%, 80.3% and 85.5%, respectively. The removal efficacy of hydrophyte species including cattail, water hyacinth, duck weed and water cabbage was 96.2%, 72.2%, 60.4% and 93.3%, respectively for Cd, while 83.6%, 82.3%, 90.0% and 81.7% for Cu and 95.9%, 78.0%, 91.3% and 97.1% for Pb, respectively. Findings of T-Test and One-Way ANOVA showed that the concentrations of Cd, Cu and Pb in IWW were significantly (P ≤ 0.01) reduced by the treatment of hydrophytes revealing the higher efficiency of CW and selected species used in this study. The HMs were removed in order of Pb > Cu > Cd. Most efficient removal for Cd was found by water cabbage, Cu by duck weed and Pb by water hyacinth. It was concluded that CW is one of the environmentally friendly and cost-effective technologies that can be used for the treatment of IWW due to the efficiency of hydrophytes species in terms of HMs removal.

Anatomical and ultrastructural studies on gelatinous fibers in the organs of non-woody xerophytic and hydrophytic species

Gelatinous fibers (G-layer) occur widely in various organs and plant tissues of both primary and secondary origin, but they are best known in tension wood. Here, we describe the occurrence, distribution patterns, and structural features of G-fibers in non-woody species of xerophytes and hydrophytes in Brazilian Cerrado (dry soil) and Chaco (wet or periodically waterlogged soils). G-fibers were present in all of the studied species, but were more abundant and more developed in xerophytes. They were associated with the phloem of leaves and primary stems and with the xylem of three xerophytic species that exhibited incipient secondary growth. The G-layer was non-lignified and characterized by greater thickness, lower density, and loose appearance in relation to the secondary layers. Under a transmission electron microscope, G-fibers displayed two secondary parietal layers (S1 and S2) in Prosopis rubriflora Hassle. (xerophyte), three secondary layers (S1, S2, and S3) in Eriosema campestre Benth. var. campestre (xerophyte), and a single secondary layer (S1) in Ludwigia leptocarpa Nutt. (hydrophyte). In P. rubriflora, mature G-fibers exhibited a loose-appearing electron-lucent region (transition zone) between G- and S-layers (secondary layers). In addition to mechanical support, this study suggests the involvement of G-fibers in water storage.

БИОЛОГИЧЕСКАЯ ОЦЕНКА МАЛЫХ ВОДОЕМОВ, РАСПОЛОЖЕННЫХ В ПАРКОВЫХ ЗОНАХ ГОРОДА МОСКВЫ

The article describes the biological and ecological state of ponds of three park zones located in northern, central and western administrative districts of Moscow. The area of reservoirs varied from 0.12 to 3.71 ha, average depth varied from 1.12 to 2.4 m. The analysis of hydrobiological material in accordance with existing criteria has been carried out. Total and seasonal concentration and biomass of phytoplankton, zooplankton and benthos are determined. During observation period in composition of algocenosis prevailed representatives of following groups of algae: Volvocophyceae, Desmidiales, Bacillariophyta, Xanthophyta, Zygnematophyceae, Chrysophyta, Pyrrophyta, Protococcophyceae, Cyanophyta, Euglenophyta. Concentration of algae in ponds varied from 0.58 up to 6.78 mln/l, total biomass varied from 0.87 to 9.70 mg/l. Zooplankton of the inspected ponds was represented by species of three systematic groups: Rotatoria, Cladocera and Copepoda. Concentration of zooplankton organisms varied from 0.0055 to 3.9432 mln/m3, biomass varied from 0.05 to 18.60 g/m3. Zoobenthos included Oligochaeta, Clitellata and insect larvae (Chironomidae, Ephemeroptera, Trichoptera). Prevalence of various representatives of plankton groups depended on the season of the year. In zoobentos samples there were found oligochaeta, chironomid and mayfly larvae, caddisflies and leeches. Higher plants were represented by 8 hydrophytic species, 1 species with floating leaves and 10 aerial coastal species. Ichthyofauna of ponds included 12 species among which aborigen species were common carp, crucian carp, roach, bream, tench, verkhovka, Amur sleeper, pike, perch, pike-perch; invasive species were grass carp, silver carp. The investigations of the large Golytsinsky pond have demonstrated that episodic releases of silver carp (spotted and hybrid) make possible to utilize both zooplankton and phytoplankton, and release of grass carp helps utilize higher water plants.

The water clarity of Polish lakes with charophyte vegetation in the years 1953-1968

Abstract A total of 313 lakes with charophyte vegetation were identified based on the data presented in 1111 manuscripts under the shared title of “Assumptions for the fisheries management project in Lake (lake name)”, based on the results of an environmental inventory carried out by the Inland Fisheries Institute in 1953-1968. The lakes’ morphological characteristics were described, hydrophyte species that most frequently accompanied charophytes were identified, differences in summer water transparency were analyzed in 281 lakes with charophyte vegetation and the results were compared with the observations made in 657 other lakes, and the potential trophic state of lakes with charophyte vegetation was determined using Carlson’s trophic state index (1996). More than half (54%) of 171 dimictic lakes with charophyte vegetation were classified as mesotrophic and 31% as oligotrophic, whereas 50% of 110 polymictic lakes were classified as eutrophic, and 40% as mesotrophic. The frequency of taxa that contribute to the eutrophication (degradation) of water bodies, including Ceratophyllum spp. Myriophyllum spp. and Elodea canadensis, increased with a decrease in the percentage of charophytes in communities of submerged hydrophytes. Regardless of the proportion of charophytes in submerged hydrophyte communities, water in the lakes colonized by charophytes was more transparent than in the 659 lakes without charophytes. Water in many polymictic and dimictic lakes with charophyte vegetation, including lakes with a small contribution of charophytes, was more transparent than in lakes without charophytes, which suggests that charophytes are sensitive indicators of water quality and are components of ecological memory in aquatic ecosystems.

Vegetation response to invasive Tamarix control in southwestern U.S. rivers: a collaborative study including 416 sites.

Most studies assessing vegetation response following control of invasive Tamarix trees along southwestern U.S. rivers have been small in scale (e.g., river reach), or at a regional scale but with poor spatial-temporal replication, and most have not included testing the effects of a now widely used biological control. We monitored plant composition following Tamarix control along hydrologic, soil, and climatic gradients in 244 treated and 172 reference sites across six U.S. states. This represents the largest comprehensive assessment to date on the vegetation response to the four most common Tamarix control treatments. Biocontrol by a defoliating beetle (treatment 1) reduced the abundance of Tamarix less than active removal by mechanically using hand and chain-saws (2), heavy machinery (3) or burning (4). Tamarix abundance also decreased with lower temperatures, higher precipitation, and follow-up treatments for Tamarix resprouting. Native cover generally increased over time in active Tamarix removal sites, however, the increases observed were small and was not consistently increased by active revegetation. Overall, native cover was correlated to permanent stream flow, lower grazing pressure, lower soil salinity and temperatures, and higher precipitation. Species diversity also increased where Tamarix was removed. However, Tamarix treatments, especially those generating the highest disturbance (burning and heavy machinery), also often promoted secondary invasions of exotic forbs. The abundance of hydrophytic species was much lower in treated than in reference sites, suggesting that management of southwestern U.S. rivers has focused too much on weed control, overlooking restoration of fluvial processes that provide habitat for hydrophytic and floodplain vegetation. These results can help inform future management of Tamarix-infested rivers to restore hydrogeomorphic processes, increase native biodiversity and reduce abundance of noxious species.

Endophyte distribution and comparative analysis of diversity in wetlands showing contrasting geomorphic conditions

The distribution and diversity of endophytic fungi in native hydrophytes from Korea were investigated. Fourteen hydrophytes (i.e., Hydrocharis dubia, Iris pseudacorus, Miscanthus sacchariflorus, Miscanthus sinensis, Nymphoides peltata, Nymphaea tetragona, Nelumbo nucifera, Pistia stratiotes, Salvinia natans, Sagittaria trifolia, Trapa japonica, Typha orientalis, Vallisneria natan, and Zizania latifolia) were sampled from freshwater marshes. A total of 216 fungal endophytes, isolated purely on the basis of morphological differences, were identified by ITS1-5.8S-ITS2 rDNA sequence similarity. The hydrophytes harbored a variety of endophytic fungi, most of which belonged to three phyla, seven classes, and 43 genera. Dramatic differences in diversity values were found among the six marshes, even within the same hydrophyte species. This distinguishing diversity or distribution of endophytes correlated with the specific environmental features but not the plant taxon. Several endophyte genera that have been reported to have biological activity (PGPR, ISR) were identified. This study provided basic data on the symbiotic relationship between hydrophytes and their endophytic fungi.