Species Myriophyllum Spicatum Research Articles

Competitive advantages of Najas marina L. in a process of littoral colonization in the lake Velenjsko jezero (Slovenija)

Najas marina is the dominant macrophyte species in Velenjsko jezero. It appeared in the lake in 1997 and soon prevailed over the species Myriophyllum spicatum L. and Potamogeton crispus L., which used to be the two most abundant species in the lake in the past. The physicochemical and geomorphological characteristics of the lake are discussed in relation to the attributes of Najas marina, presenting competitive advantages in this environment. Conditions in the lake such as warm water and unstable sediment enabled successful growth and life strategy of Najas marina, which is a summer-annual plant with short life cycle, quick propagation from seeds and a very extensive root system.

Classification of Eurasian Watermilfoil (Myriophyllum spicatum) Using Drone-Enabled Multispectral Imagery Analysis

Remote sensing approaches that could identify species of submerged aquatic vegetation (SAV) and measure their extent in lake littoral zones would greatly enhance SAV study and management, especially if these approaches can provide faster or more accurate results than traditional field methods. Remote sensing with multispectral sensors can provide this capability, but SAV identification with this technology must address the challenges of light extinction in aquatic environments where chlorophyll, dissolved organic carbon, and suspended minerals can affect water clarity and the strength of the sensed light signal. Here, we present an uncrewed aerial system (UAS)-enabled methodology to identify the extent of the invasive SAV species Myriophyllum spicatum (Eurasian watermilfoil, or EWM), primarily using a six-band Tetracam multispectral camera, flown over sites in the Les Cheneaux Islands area of northwestern Lake Huron, Michigan, USA. We analyzed water chemistry and light data and found our sites clustered into sites with higher and lower water clarity, although all sites had relatively high water clarity. The overall average accuracy achieved was 76.7%, with 78.7% producer’s and 77.6% user’s accuracy for the EWM. These accuracies were higher than previously reported from other studies that used remote sensing to map SAV. Our study found that two tested scale parameters did not lead to significantly different classification accuracies between sites with higher and lower water clarity. The EWM classification methodology described here should be applicable to other SAV species, especially if they have growth patterns that lead to high amounts of biomass relative to other species in the upper water column, which can be detected with the type of red-edge and infrared sensors deployed for this study.

Seasonal dynamics of the macrophyte test species Myriophyllum spicatum over two years in experimental ditches for population modeling application in risk assessment.

Myriophyllum spicatum is a sediment‐rooted, aquatic macrophyte growing submerged, with a wide geographical distribution and high ecological relevance in freshwater ecosystems. It is used in testing and risk assessment for pesticides in water and sediment. Population models enable effects measured under laboratory conditions to be extrapolated to effects expected in the field with time‐variable environmental factors including exposure. These models are a promising tool in higher‐tier risk assessments. However, there is a lack of data on the seasonal dynamics of M. spicatum, which is needed to test model predictions of typical population dynamics in the field. To generate such data, a two‐year study was set up in outdoor experimental systems from May 2017 to May 2019. The growth of M. spicatum was monitored in 0.2025 m2 plant baskets installed in an experimental ditch. Parameters monitored included biomass (fresh weight [FW] and dry weight [DW]), shoot length, seasonal short‐term growth rates of shoots, relevant environmental parameters, and weather data. The results showed a clear seasonal pattern of biomass and shoot length and their variability. M. spicatum reached a maximum total shoot length (TSL) of 279 m m−2 and a maximum standing crop above‐ground DW of 262 g m−2. Periodical growth rates reached up to 0.072, 0.095, and 0.085 day−1 for total length, FW, and DW, respectively. Multivariate regression revealed that pH (as a surrogate for the availability of carbon species) and water temperature could explain a significant proportion of the variability in M. spicatum growth rates (p < 0.05). This study has provided an ecologically relevant data set on seasonal population dynamics representative of shallow freshwater ecosystems, which can be used to test and refine population models for use in chemical risk assessment and ecosystem management. Integr Environ Assess Manag 2022;18:1375–1386. © 2021 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Comprehensive Insight into Lake Nasser Environment: Water Quality and Biotic Communities—A Case Study before Operating the Renaissance Dam

This study focused on the monitoring and assessment of aquatic ecosystem functioning based on the abiotic and biotic features of Lake Nasser in the post-flood and pre-flood periods as the last ones before water storing behind the Grand Ethiopian Renaissance Dam. The physicochemical parameters, distribution and structure of biotic communities, including bacteria, phytoplankton, zooplankton, macrophytes, epiphytes and fish were analyzed at 15 sites. The values of most parameters (primarily temperature, total suspended solids, pH, orthophosphates, carbonates, sulphates and some cations) were higher in the pre-flood period, whereas higher values of conductivity, total dissolved solids, total solids, nitrites, nitrates, chemical oxygen demand, bicarbonates and chlorophyll a were recorded in the post-flood period. Cyanobacteria-dominated phytoplankton and total coliform bacteria were more abundant in the pre-flood period, and especially at sites 10–15, whereas higher abundances of zooplankton were recorded in the post-flood period. All these changes in parameters were significantly differentiated, and only the concentrations of dissolved oxygen, biochemical oxygen demand, ammonium and silicates were at similar level in both periods. The study also indicated that environmental factors had affected the macrophyte distribution and the adaptation of the invasive species Myriophyllum spicatum to thrive under different environmental factors in the lake. Besides, macrophytes provided the habitat to other aquatic organisms, especially epiphytes, and also helped maintaining the good water quality, nutrient cycling and stabilizing rivers’ and lakes’ banks. Generally, these conditions were rather favorable for biological processes and fish production.

Diversity of Macrophytes and Environmental Assessment of the Ljubljanica River (Slovenia)

The present research aimed to determine the diversity of macrophyte taxa in the Ljubljanica River and its relationship with environmental parameters. In each of the 19 river sections, the presence and abundance of plant taxa were recorded, and basic physical and chemical parameters were measured. Additionally, selected environmental parameters were assessed using a modified version of the Riparian, Channel and Environmental (RCE) method. We compared the obtained data set with survey data from the year 2004. In 2019, a total of 34 macrophyte taxa were recorded. The dominant taxa with the highest abundance were Sparganium emersum, Callitriche sp., and the invasive alien species Elodea canadensis. The species richness and diversity of macrophytes decreased with distance from the source, an increase in pH, and alterations of the riverbed structure due to interference in the riverine ecosystem in the lower part of the Ljubljanica River and its catchment. The comparison of 2004 and 2019 surveys revealed a decrease in the overall presence and abundance of P. natans and in the frequency of occurrence of the species Myriophyllum spicatum and an increase in the presence and abundance of the invasive alien species Elodea canadensis.

Effects of Diversity, Coverage and Biomass of Submerged Macrophytes on Nutrient Concentrations, Water Clarity and Phytoplankton Biomass in Two Restored Shallow Lakes

Transplantation of submerged macrophytes to restore shallow lakes has been used as an effective measure to maintain a clear water state. Water quality is highly correlated with submerged macrophytes community, however, the relationships between water quality and the diversity, coverage and biomass of submerged macrophytes are, so far, not yet well studied. We analyzed the correlations of nutrient concentrations, water clarity and phytoplankton biomass with the metrics of submerged macrophytes community in two Chinese restored shallow subtropical lakes, Lake Wuli (Wuli-E, 5 ha) and Lake Qinhu (Qin-E, 8 ha). A similar biomass of submerged macrophytes was transplanted into each lake, while both the species richness and coverage of macrophytes in Qin-E were lower than Wuli-E. After a 1–2-year restoration, the diversity almost had no change, but the biomass density and coverage decreased in Wuli-E. As for Qin-E, the coverage of submerged macrophytes increased but biomass density and diversity decreased. The dominance of canopy-forming submerged macrophyte species Myriophyllum spicatum was observed in Qin-E and less meadow-forming biomass and species was observed than that in Wuli-E. Moreover, it was also observed that Wuli-E had a better water quality than that of Qin-E after transplantation. Path analysis results showed that macrophyte coverage and the diversity related to meadow-forming species (e.g., Vallisneria spinulosa) had strong effects on enhancing clarity and reducing nutrient concentrations. But the high biomass density accompanied by the canopy-forming species like M. spicatum was unfavorable for controlling nutrients. Our results provide important insight into the different roles that macrophyte diversity, biomass and coverage play in improving water clarity and controlling nutrient concentrations. This new knowledge will be instrumental in implementing more effective lake restoration, especially using macrophyte transplantation as a restoration tool in warm shallow lakes.

Glutamate dehydrogenase plays an important role in ammonium detoxification by submerged macrophytes

Ammonium is a paradoxical chemical because it is a nutrient but also damages ecosystems at high concentration. As the most eco-friendly method of water restoration, phytoremediation technology still faces great challenges. To provide more theoretical support, we exploited six common submerged macrophytes and selected the most ammonium-tolerant and -sensitive species; then further explored and compared the mechanisms underlying ammonium detoxification. Our results showed the activity of glutamate dehydrogenase (GDH) in the ammonium-tolerant species Myriophyllum spicatum leaves performed a dose-response curve (increased 169% for NADH-dependent GDH and 103% for NADPH-dependent GDH) with the [NH4+-N] increasing from 0 to 100 mg/L while glutamine synthetase (GS) activity slightly changed. But for the ammonium-sensitive species, Potamogeton lucens, the activity of GDH recorded no major changes, while the GS increased slightly (17%). Based on this, we conclude that the alternative pathway of GDH is more important than the pathway catalyzed by GS in determining the tolerance of submerged macrophytes to high ammonium concentration (up to 100 mg N/L). Our present study identifies submerged macrophytes that are tolerant of high concentrations of ammonium and provides mechanistic support for practical water restoration by aquatic plants.

Falling into pieces: In situ fragmentation rates of submerged aquatic plants and the influence of discharge in lowland streams

The formation and dispersal of viable plant fragments are considered as key determinants for the vegetative spread potential and competitive strength of submerged aquatic macrophytes. Although it is known that the disturbance by flow facilitates fragment dispersal in streams, detailed information on in situ fragmentation rates and the influence of discharge are still lacking. We determined the fragmentation rates (i.e. number of fragments per biovolume of a given species) of the four widespread aquatic plant species Myriophyllum spicatum, Potamogeton crispus, Elodea canadensis and Elodea nuttallii in defined sections of small to medium-sized German streams with different flow regimes. We further measured chlorophyll a fluorescence (Fv/Fm: maximum quantum yield of photosystem II) to denote the viability of plant fragments collected in the field. We documented stream- and species-specific differences in fragmentation rate, ranging from 74 ± 20 (P. crispus) up to 1260 ± 376 fragments m−3 specific biovolume d-1 (E. canadensis; ± SE). Fragmentation rates generally increased in streams characterized by rather high discharge conditions but were negligibly associated with minor discharge fluctuations at a given stream section. This effect was significant for M. spicatum and E. nuttallii, but not for P. crispus and E. canadensis. Overall, a high portion of fragments was viable, as indicated by Fv/Fm values > 0.58 in 95% of all fragments. Our results demonstrate that fragmentation rates of submerged aquatic plants are to a certain extent controlled by the discharge conditions of a stream and highlight the strong vegetative spread potential of the four species studied.

Seventeen years of grass carp: an examination of vegetation management and collateral impacts in Ball Pond, New Fairfield, Connecticut

ABSTRACTJune-Wells M, Simpkins T, Coleman AM, Henley W, Jacobs R, Aarrestad P, Buck G, Stevens C, Benson G. 2017. Seventeen years of grass carp: an examination of vegetation management and collateral impacts in Ball Pond, New Fairfield, Connecticut. Lake Reserve Manage. 33:84–100.Ball Pond is a 32 ha meso-eutrophic lake located in the Marble Valley of Connecticut. The local bedrock geology and watershed influences have resulted in a hardwater system with limited plant community diversity and an assemblage dominated by the nonnative species Myriophyllum spicatum. By 1996, M. spicatum dominated 32% of the waterbody, and residents were concerned their property values would fall as the recreational value of the lake diminished. In an attempt to remedy this issue, 400 grass carp (Ctenopharyngodon idella; ∼30 cm length) were released in 1997 at a rate of 38 per vegetated hectare. As a requirement of the state permit, the plant community, water quality, and the fish community were monitored throughout the initiative (1997–2014) to examine the impact of grass carp at multiple ecological levels of the lentic system. M. spicatum was significantly reduced in biomass and cover between 1997 and 2014, with no change in plant community richness. Concordant with the decrease in M. spicatum, the cover of Ceratophyllum demersum increased significantly and became more dominant in the plant community as M. spicatum was reduced. Our results also suggest there was no change in water quality or fish community density/diversity during the study period; however, fish community richness was reduced. Bluegill (Lepomis macrochirus) density and largemouth bass (Micropterus salmoides) size distribution both increased during this study. We assert that grass carp can be an effective approach to nonnative plant management in a northern meso-eutrophic lake.

How TK-TD and population models for aquatic macrophytes could support the risk assessment for plant protection products.

This case study of the Society of Environmental Toxicology and Chemistry (SETAC) workshop MODELINK demonstrates the potential use of mechanistic effects models for macrophytes to extrapolate from effects of a plant protection product observed in laboratory tests to effects resulting from dynamic exposure on macrophyte populations in edge-of-field water bodies. A standard European Union (EU) risk assessment for an example herbicide based on macrophyte laboratory tests indicated risks for several exposure scenarios. Three of these scenarios are further analyzed using effect models for 2 aquatic macrophytes, the free-floating standard test species Lemna sp., and the sediment-rooted submerged additional standard test species Myriophyllum spicatum. Both models include a toxicokinetic (TK) part, describing uptake and elimination of the toxicant, a toxicodynamic (TD) part, describing the internal concentration-response function for growth inhibition, and a description of biomass growth as a function of environmental factors to allow simulating seasonal dynamics. The TK-TD models are calibrated and tested using laboratory tests, whereas the growth models were assumed to be fit for purpose based on comparisons of predictions with typical growth patterns observed in the field. For the risk assessment, biomass dynamics are predicted for the control situation and for several exposure levels. Based on specific protection goals for macrophytes, preliminary example decision criteria are suggested for evaluating the model outputs. The models refined the risk indicated by lower tier testing for 2 exposure scenarios, while confirming the risk associated for the third. Uncertainties related to the experimental and the modeling approaches and their application in the risk assessment are discussed. Based on this case study and the assumption that the models prove suitable for risk assessment once fully evaluated, we recommend that 1) ecological scenarios be developed that are also linked to the exposure scenarios, and 2) quantitative protection goals be set to facilitate the interpretation of model results for risk assessment.

Spatial pattern of native species Myriophyllum spicatum and invasive alien species Elodea nuttallii after introduction of the latter one into the Drava River (Slovenia)

Invasive alien species Elodea nuttallii was introduced into the Drava River (Slovenia) in 2007. The spatial distribution of native macrophyte species Myriophyllum spicatum and the invasive alien species E. nuttallii was studied in two impoundments, HPP Vuhred and HPP Mariborski otok in the years 2009, 2010 and 2011. The very heterogeneous environment of the Drava River had resulted in dynamic and non-uniform distributions of E. nuttalli and M. spicatum in both impoundments. The distribution of E. nuttalli was shown to be suppressed in river stretches exposed to great turbulence. It had, however, successfully invaded areas with gentle slope of littoral, low exposition to main water flow and muddy sediment and prevailed against the native species M. spicatum. The latter was more abundant than E. nuttallii in stretches exposed to higher flow velocity. Thus, the competitive success of M. spicatum and E. nuttallii depended on environmental conditions. Our results lead to the prediction that E. nuttallii will increase further in the river Drava, causing serious economic problems.

Distribution and limnological drivers of submerged aquatic plant communities in Lake Simcoe (Ontario, Canada): Utility of macrophytes as bioindicators of lake trophic status

Species composition, distribution, and biomass of submerged aquatic plants were studied in Lake Simcoe (Ontario, Canada) as was the use of macrophytes as indicators of lake trophic status. While previous studies in this lake targeted one eutrophic embayment, this study covered the entire lake area, identified five areas of high plant biomass and recorded 16 macrophyte species; the community was dominated by Ceratophyllum demersum (39.1% of the total biomass), the invasive species Myriophyllum spicatum (27.4%), Elodea canadensis (10.7%) and Chara spp. (9.7%). Canonical correspondence analysis (CCA) identified four significant limnological variables related to plant biomass: (a) depth, likely a proxy for light levels; (b) substrate type, related to nutrient availability, stability, and wave exposure; (c) phosphorus loading from the closest tributary; and (d) size of the area drained by a tributary. Since initial (1971) macrophyte surveys on Lake Simcoe, the community has been dramatically altered by expansion of an invasive species (i.e. M. spicatum) resulting in declines of native shallow-water species (e.g. Chara spp.). The arrival of zebra mussels ( Dreissenia polymorpha) ~ 1995 and reductions in phosphorus loading have increased water clarity, extending the maximum depth of plant colonization (6.0 m in 1984 to 10.5 m in 2008), and almost tripled macrophyte biomass (1.2 kg·m −2 in 1984 to 3.1 kg·m −2 in 2008). Increased plant biomass, and a loss of species diversity due to spread of M. spicatum are interpreted by macrophyte indices as a decrease in lake trophic status, which likely explains why these indices did not follow trends in reduced phosphorus loading.

Colonisation of temporary macrophyte substratum by midges (Chironomidae: Diptera)

This study investigates a phytophylous community of Chironomidae larvae on the submerged plant species Myriophyllum spicatum L. in a eutrophic lake (Lake Sakadas, Danube floodplain area in Croatia) during summer 2004. This macrophyte species appeared for the first time in the lake in 2004, lasted approximately three months and was considered as a temporary habitat. The chironomid community was very abundant in the stands of this macrophyte species, which developed at three sites. The recorded species belong to three subfamilies: Chironominae (Chironomini and Tanytarsini), Orthocladiinae and Tanypodinae. Species composition varied in time, though Orthocladiinae with their representative Cricotopus sylvestris gr. dominated throughout the entire sampling period, accounting for approx. 60% of the total community. However, the presence of this species group experienced a marked drop to only 10% in September when Chironomini larvulae and Paratanytarsus sp. prevailed. Furthermore, the share of Endochironomus albipennis (Meigen 1830) in relation to other species was also consistently higher. NMDS ordination and cluster analysis separated three main colonization periods based on larval abundance. RDA analysis indicated the influence of environmental variables, especially Secchi depth, macrophyte dry weight, depth and water temperature, on chironomid community structure.

Mesohaline Submerged Aquatic Vegetation Survey Along the U.S. Gulf of Mexico Coast, 2001 and 2002: A Salinity Gradient Approach

Distribution of marine submerged aquatic vegetation (SAV; i.e., seagrass) in the northern Gulf of Mexico coast has been documented, but there are nonmarine submersed or SAV species occurring in estuarine salinities that have not been extensively reported. We sampled 276 SAV beds along the gulf coast in Florida, Alabama, Mississippi, Louisiana, and Texas in 2001 and 2002 in oligohaline to polyhaline (0 to 36 parts per thousand) waters to determine estuarine SAV species distribution and identify mesohaline SAV communities. A total of 20 SAV and algal species was identified and habitat characteristics such as salinity, water depth, pH, conductivity, turbidity, dissolved oxygen, and sediment composition were collected. Fourteen SAV species occurred two or more times in our samples. The most frequently occurring species was Ruppia maritima L. (n = 148), occurring in over half of SAV beds sampled. Eleocharis sp. (n = 47), characterized with an emergent rather than submerged growth form, was a common genus in the SAV beds sampled. A common marine species was Halodule wrightii Asch. (n = 36). Nonindigenous species Myriophyllum spicatum L. (n = 31) and Hydrilla verticillata (L. f.) Royle (n = 6) were present only in oligohaline water. Analyzing species occurrence and environmental characteristics using canonical correspondence and two-way indicator species analysis, we identify five species assemblages distinguished primarily by salinity and depth. Our survey increases awareness of nonmarine SAV as a natural resource in the gulf, and provides baseline data for future research.

Within-Bed Distribution of Myriophyllum spicatum L. in Lake Onalaska, Upper Mississippi River

ABSTRACT The exotic species Myriophyllum spicatum L. has become a recent member of the submersed aquatic plant community within the upper Mississippi River system (UMRS). Notable for nuisance growth in many North American locations, its potential for creating problems in the river system is not known. To better understand its nuisance potential, within-bed-plant pattern and the relationship between plant biomass, water depth, sediment moisture, and sediment organic content were studied in Lake Onalaska, a backwater lake of UMRS Pool 7. These results were compared with studies of biomass distribution of M. spicatum in Lake Wingra, Wisconsin. Within-bed biomass from Lake Onalaska was not significantly correlated with depth, organic matter, or sediment moisture. Lake Onalaska milfoil beds produced biomass similar to other lakes in the region but were restricted to much shallower water depths. The shallow maximum growth depth is probably related to poor water clarity but the maximum growth depth could vary significantly from year to year because of the dynamic nature of water clarity in the UMRS. Because Mississippi River pools are shallow, the area occupied by milfoil could also vary considerably from year to year.

PCB Concentrations and Congener Composition in Macrophytes and Sediments in the St. Lawrence River near Cornwall, Ontario

PCB concentration and congener composition were examined in sediments and two species of macrophytes in the St. Lawrence River downstream of Cornwall, Ontario. Total PCBs in the macrophytes ranged from 37 to 585 ng/g dry weight, with biota to sediment accumulation factors ranging from 0.3 to 10. The floating-leaved species Nuphar variegatum had generally higher PCB concentrations than the submerged species Myriophyllum spicatum, but the latter had higher biota to sediment accumulation factors. N. variegatum also had a higher lipid content, but lipid levels were not a good predictor of plant PCB concentrations. Congener specific analysis showed congener patterns shifted between plants and sediments; macrophytes tended to have higher levels of tetrachlorobiphenyl congeners. Given that contaminant levels in plants reflect those found in the sediments, the high biomass of macrophytes within the river and particularly in Lake St. Francis represents an important reserve of PCBs which may be transferred to the herbivorous and detrital food webs.