Species Elodea Research Articles

Ecology of Elodea canadensis Michx. and Elodea nuttallii (Planch.) H. St. John-Insights from National Water Monitoring in Croatia.

Elodea canadensis Michx. (common waterweed) and Elodea nuttallii (Planch.) H. St. John (Nuttall's waterweed), two invasive aquatic plants from North America, have coexisted in European water bodies since the early 20th century. New localities for both species in Croatia continued to be discovered during a study that ran from 2016 to 2023 as a part of the annual implementation of Water Framework Directive monitoring that covered the entire territory of Croatia (786 sampling points in total). Based on these data, the distribution and ecology of both species were analysed. Elodea canadensis was found at 30 sampling points, mostly in rivers, and E. nuttallii at 15 sampling points, mostly in artificial canals. Nearly three-quarters (72.5%) of all elodea sampling points were in the Pannonian Ecoregion. Elodea canadensis was discovered for the first time in the Continental-Dinaric and Mediterranean-Dinaric Subecoregions. To study the ecology of the species, for each sampling point, vegetation relevés were performed and monthly measurements of physico-chemical parameters were collected. The most common accompanying species for both elodeas are presented, and the difference in species assemblages between the sites with E. canadensis and E. nuttallii was confirmed with the ANOSIM test. Furthermore, Indicator Species Analysis revealed eight species characteristic of E. canadensis sites and eleven species characteristic of E. nuttallii sites. Fitting multivariate models (CCA and NPMR) to species abundance revealed the ecological reaction of E. canadensis and E. nuttallii to environmental descriptors. The most strongly contributing environmental descriptors that influence the distribution of both Elodea species are biochemical oxygen demand, electrical conductivity and total phosphorus. In Croatia, the replacement of E. canadensis with E. nuttallii was observed in several water bodies with high nutrient loads.

Current distribution, trends, abiotic and biotic preferences of two Elodea species in Bulgaria

Two invasive aquatic macrophyte species from the genus Elodea and their distribution in Bulgaria were studied. The research was based on 653 field surveys from the period 2009-2022. Elodea records constitute to only 6% of the database. Between the two species studied, E. nuttallii exhibited a wider distribution both in rivers and lakes (natural and artificial). Several instances of invaders? dominance were observed, with E. nuttallii showing dominance patterns mainly in lakes, and E. canadensis in rivers. Both species were distributed in aquatic habitats with a wide variation in abiotic characteristics, except for the dominant substrate. E. nuttallii showed a more significant altitudinal range reaching above 1500 m. Such altitudinal variations resulted in diverse ecological habitats in terms of abiotic factors such as temperature and light intensity. The studied aquatic macrophyte communities demonstrated average species richness. Ceratophyllum demersum and Myriophyllum spicatum were the most commonly recorded representatives of the native aquatic flora. Canadian waterweed demonstrated the ability to form dense communities in rivers, while Nuttall?s waterweed retained average values of abundance. A case of natural disappearance within the Elodea species has been documented. The systematised information covering a 13-year period could serve to identify strategic areas for monitoring aquatic IAS and their management.

МАКРОФИТЫ РОДА POTAMOGETON — БИОИНДИКАТОРЫ НАКОПЛЕНИЯ ТЯЖЕЛЫХ МЕТАЛЛОВ

This work presents the investigation of the content of some heavy metals in the pondweeds of the Lower Volga River Delta within the area of Astrakhan State Biosphere Reserve. Higher aquatic plants extract chemical elements both from bottom sediments and water column. Moreover, the macrophytes, namely the representatives of Potamogeton genus, are capable of extraction and accumulation of the metals dissolved in the water, contained in the suspended colloidal particles, and present on the surface of leaves. This work is aimed at the identification of species-specific features of the typical hydatophytes—aquatic plants of Potamogeton genus—pertaining to the accumulation of heavy metals. The content of chemical elements in the investigated specimens has been identified using atomic absorption spectrometry; the results have been processed with statistical methods. It has been found that all investigated plant species accumulate iron and manganese in the highest quantities and cobalt and cadmium in the lowest. The investigated pondweed species have shown species-specific properties in the accumulation of chemical elements. Potamogeton crispus and Potamogeton lucens are found to be iron concentrating species. Potamogeton lucens also accumulates nickel, iron and manganese, and Potamogeton pectinatus accumulates chrome, cobalt and lead.

Waterbodies in the Floodplain of the Drava River Host Species-Rich Macrophyte Communities despite Elodea Invasions

The contribution discusses macrophyte communities in natural and man-made waterbodies located on the active floodplain along the Drava river (Slovenia). We presumed that these different types of wetlands host a great number of macrophyte species, but this diversity may be affected by the presence of alien invasive species Elodea canadensis and E. nuttallii. Presence, relative abundance, and growth forms of plant species along with selected environmental parameters were monitored. Correlation analyses and direct gradient analyses were performed to reveal the possible relations between the structure of macrophyte community and environmental parameters. Number of macrophytes in surveyed water bodies varied from 1 to 23. Besides numerous native species we also recorded Elodea canadensis and E. nuttallii, which were present in 19 out of 32 sample sites, with E. nuttallii prevailing. The less invasive E. canadensis was absent from ponds and oxbow lakes but relatively abundant in side-channels, while E. nuttallii was present in all types but dominant in ponds. The most abundant native species were Myriophyllum spicatum and M. verticillatum, Ceratophyllum demersum and Potamogeton natans. Correlation analyses showed no negative effect of the invasive alien Elodea species to the species richness and diversity of native flora. Positive correlation between the abundance of E. nuttallii and temperature of the water was obtained.

Pondweeds of Florida

This new 9-page factsheet describes the defining characteristics of the eleven pondweed species that are present in Florida. It serves as a pondweed identification guide for aquatic habitat managers, lake monitors, conservationists, and plant enthusiasts, and it gives some context on each species’ life history and ecological role. Written by Christine Rohal, Laura Reynolds, Carrie Reinhardt Adams, and Charles Martin, and published by the UF/IFAS Department of Soil and Water Sciences.https://edis.ifas.ufl.edu/ss686

Gimme Shelter: differential utilisation and propagule creation of invasive macrophytes by native caddisfly larvae

In aquatic systems, invasive submerged macrophytes considerably alter the structure and functioning of communities, thus potentially compromising ecosystem services. The prolific spread of invasive macrophytes is often aided by vegetative fragment propagation, yet the contributions of various commonly occurring invertebrates to such fragmentation are often unquantified. In the present study, we examine fragmentary spread of invasive macrophytes by a group of shredder-herbivores, larval caddisflies. Through novel application of the comparative functional response (FR; resource use as a function of density) approach to the native case-building species Limnephilus lunatus, we compared utilisation of non-native waterweeds Elodea canadensis and E. nuttallii in mono- and polycultures. Furthermore, we quantified de-cased and cased caddisfly-induced fragment production and length changes among non-native E. canadensis, E. nuttallii, Crassula helmsii and Lagarosiphon major under two different plant orientations: horizontal (floating) versus vertical (upright) growth forms. Larval caddisflies exhibited Type II (hyperbolic) FRs towards both Elodea species, and utilised each plant at similar rates when plants were provided separately. When plant species were presented in combination horizontally, E. canadensis was significantly less utilised compared to E. nuttallii, corroborating observations in the field. De-cased larvae produced new plant fragments for all four aquatic macrophytes, whereas cased larvae fragmented plants significantly less. Elodea nuttalii and C. helmsii were fragmented the most overall. Crassula helmsii was utilised to the greatest extent when plants were horizontally orientated, and Elodea species when vertically orientated. This study identifies and quantifies a mechanism from a novel species group that may contribute to the spread of invasive macrophytes in aquatic systems. Whilst exploititative interactions are thought to impede invasion success, here we demonstrate how resource utilisation by a resident species may exacerbate propagule pressure from an invasive species.

The Ecophysiological Response of Two Invasive Submerged Plants to Light and Nitrogen

Two submerged Elodea species have small differences in their ecophysiological responses when exposed to individual environmental factors. However, field observations showed that under eutrophic conditions with low light availability, Elodea canadensis could be displaced by Elodea nuttallii. Here we investigated the combined effect of environmental factors on the ecophysiological response of the two species in order to explain the differences in their invasion successes. We cultivated the plants in aquaria containing five different nitrogen (N) concentrations and incubated at five different light intensities. For both species increasing nitrogen concentrations resulted in increased relative growth rate, chlorophyll concentration, and actual photochemical efficiency of photosystem II (ΦPSII), however, they produced less roots. Lowering light intensity resulted in a lower relative growth rate, root production, and nutrient removal. In contrast, chlorophyll concentration in the leaves, and ΦPSII increased. The main difference between the two Elodea species was that the light compensation point (Ic) and weight loss in the dark were significantly higher and photochemical efficiency and chlorophyll concentration were significantly lower for E. canadensis than for E. nuttallii, indicating that the latter can survive under much more shady and hypertrophic conditions. The change in nitrogen concentration of the media and in tissue concentration of the plants indicated that E. nuttallii has a higher nitrogen removal capacity. The ecophysiological differences between the two species can be an explanation for invasion success of E. nuttallii over E. canadensis and thus may explain why the latter is replaced by the first.

Production of Pondweeds (Potamogeton, Stuckenia, Potamogetonaceae) in Rivers in the North of European Russia

For the first time, summarized data on the production of nine species and ten hybrids of pondweed (Potamogeton, Stuckenia, Potamogetonaceae) are given for ecosystems of small and medium rivers in the north of European Russia. The pondweed is shown to be an important producer of primary organic matter. A significant contribution to primary production in rivers in the region is due to large-size pondweeds and their hybrids, which form dense monodominant stands: P. lucens, P. natans, P. perfoliatus, P. × angustifolius, P. × nitens, P. × salicifolius, P. × sparganiifolius. The production characteristics for the widespread species (P. lucens, P. natans, P. perfoliatus) in the rivers of the region are more than 1.5 times greater than those in reservoirs. Most pondweed species and hybrids show medium productivity and produce <1 kg/m2 organic matter per year, and only P. lucens, P. × vepsicus, S. × fennicа are classifed as having a high productivity.

Environmental factors affecting pondweeds in water bodies of northwest Poland

Abstract In 32 lakes, 19 watercourses and 11 estuaries located along the southern Baltic coast (NW Poland) taxa of Potomogeton and Stuckenia genera were determined on the basis of 981/0.1 m2 plant samples. Environmental factors affecting them were identified on the basis of 212 water samples and 272 sediment samples. Twenty-one Potamogeton taxa were found, including four hybrids and two Stuckenia species. Twenty-one pondweed species occurred in lakes, thirteen in watercourses and ten in estuaries. There were significant differences in environmental factors in particular types of water bodies (p&lt;0.001) except for the content of organic and mineral matter and of humic acids in the sediment. There was a statistically significant difference (p&lt;0.001) between the environmental factors affecting Potamogeton and Stuckenia, respectively, within each of the waterbody types studied. In lakes, Potamogeton occupied poorer habitats than Stuckenia, with lower conductivity, redox, PAR intensity, concentration of bicarbonates, calcium and chlorides and lower calcium content in the sediment. In watercourses, Potamogeton occurred in less coloured and less oxygenated waters than Stuckenia, but richer in CO2 and chlorides, better insolated and flowing faster. It also occupied less alkaline sediment, but of higher conductivity. In estuaries, Potamogeton occurred in waters with a relatively low concentration of chlorides and calcium than Stuckenia, lower pH and conductivity, but more coloured and, consequently, with lower PAR. C&amp;RT analysis showed mineral concentration (Ca2+, Cl−, HCO3 −) in the water, its conductivity, colour and flow to be the highest-ranking environmental factors affecting pondweeds.

Broad Seed Germination Niche as an Adaptation to Heterogeneous Aquatic Habit—a Case Study of Four Potamogeton species

Aquatic habitats represent an extremely heterogeneous media for the inhabiting its plants, because key environmental factors vary there rapidly at relatively small scales. In this study, we explore the seed germination strategies of four pondweed species (Potamogeton compressus L., P. natans L., P. pectinatus L. and P. vaginatus Turcz.) in relation to the habitats they occupy. We hypothesised that, due to the high heterogeneity of aquatic environments, none of the environmental factors, such as light, temperature fluctuations or oxygen would play the role of a reliable trigger for seed germination of these species. The results of the germination experiments confirm the proposed hypothesis: under almost all conditions – fluctuating and constant temperatures, light and darkness, aerobic, flooded and hypoxia conditions – germination percentages ranged from 88.5 to 100%. An interspecific comparison of germination patterns also evidenced that all the investigated species showed the same response to all the studied environmental factors. We speculate that similar adaptations present in other aquatic macrophytes may point out the broader occurrence of this phenomenon in aquatic plants.

Phenotypic plasticity as a clue for invasion success of the submerged aquatic plant Elodea nuttallii.

Two closely related alien submerged aquatic plants were introduced into Europe. The new invader (Elodea nuttallii) gradually displaced E.canadensis even at sites where the latter was well established. The aim of the study was to evaluate the combined effects of environmental factors on several phenotypic characteristics of the two Elodea species, and to relate these phenotypic characteristics to the invasion success of E.nuttallii over E.canadensis. In a factorial design, Elodea plants were grown in aquaria containing five different nitrogen concentrations and incubated at five different light intensities. We used six functional traits (apical shoot RGR), total shoot RGR, relative elongation, root length, lateral spread, branching degree) to measure the environmental response of the species. We calculated plasticity indices to express the phenotypic differences between species. Light and nitrogen jointly triggered the development of phenotypic characteristics that make E.nuttallii a more successful invader in eutrophic waters than E.canadensis. The stronger invader showed a wider range of phenotypic plasticity. The apical elongation was the main difference between the two species, with E.nuttallii being more than two times longer than E.canadensis. E.canadensis formed dense side shoots even under high shade and low nitrogen levels, whereas E.nuttallii required higher light and nitrogen levels. We found that under more eutrophic conditions, E.nuttallii reach the water surface sooner than E.canadensis and through intensive branching outcompetes all other plants including E.canadensis. Our findings support the theory that more successful invaders have wider phenotypic plasticity.

Spontaneous hybridization of Potamogeton praelongus and Potamogeton lucens confirmed in a germination test (Czech Republic)

A hybrid of P. praelongus and P. lucens (P.×jutlandicus) was found in an outdoor germination test in 2013–2015, which confirmed existence of spontaneous hybridization of the pondweed species present in the ponds below Plešivec in the Kokořínsko Protected Landscape Area in the Czech Republic. Seedlings of P. ×jutlandicus were different from those of P. praelongus and the speed of their growth was higher. P. ×jutlandicus has not been found in natural sites in the Czech Republic yet. The Czech locality is the third one of this rare hybrid worldwide and the first one with a molecular proof.

Environmental DNA detection of aquatic invasive plants in lab mesocosm and natural field conditions

Aquatic invasive plant species cause negative impacts to economies and ecosystems worldwide. Traditional survey methods, while necessary, often do not result in timely detections of aquatic invaders, which can be cryptic, difficult to identify, and exhibit very rapid growth and reproduction rates. Environmental DNA (eDNA) is a relatively new method that has been used to detect multiple types of animals in freshwater and marine ecosystems through tissues naturally shed from the organism into the water column or sediment. While eDNA detection has proven highly effective in the detection of aquatic animals, we know less about the efficacy of eDNA as an effective surveillance tool for aquatic plants. To address this disparity, we designed mesocosm experiments with Elodea species to determine the ability to detect accumulation and degradation of the DNA signal for aquatic plants, followed by field surveillance of the highly invasive Hydrilla verticillata in freshwaters across several U.S. geographic regions. In both lab and field experiments, we designed a high sensitivity quantitative PCR assay to detect the aquatic plant species. In both experiments, plant eDNA detection was successful; we saw accumulation of DNA when plants were introduced to tanks and a decrease in DNA over time after plants were removed. We detected eDNA in the field in areas of known Hydrilla distribution. Employing eDNA detection for aquatic plants will strengthen efforts for early detection and rapid response of invaders in global freshwater ecosystems.

Regeneration and colonization abilities of the invasive species Elodea canadensis and Elodea nuttallii under a salt gradient: implications for freshwater invasibility

Salinity plays an important role in macrophyte distribution. The current increase in salinization of native freshwaters could modify their susceptibility to invasion. In this study, we determined the tolerance to salt of two invasive macrophytes: Elodea canadensis and Elodea nuttallii. We analysed their growth, regeneration and colonization abilities and the influence of their phenological stage in their response to salt in a laboratory experiment. Traits of both Elodea species varied according to the season and the salt concentration: they were more affected by salt in autumn than in spring, demonstrating higher salt tolerance in spring than in autumn. The two species were sensitive to different thresholds of salinity, although they were both strongly reduced at 3 g l−1 of salt in autumn. Consequently, salt marshes and brackish waters (salt concentration inferior to 3 g l−1 of salt) are likely to be invaded by both species, but the effect of salt levels superior to 3 g l−1 on plant invasiveness needs to be investigated.

Trade-offs between growth and defence in two phylogenetically close invasive species

The success of an invasive plant species could be explained by trade-off between growth and defence. The aim of this paper was to explore the responses of two non-native aquatic macrophytes Elodea canadensis and Elodea nuttallii to herbivores in their introduced range. We assessed the palatability of the two phylogenetically close aquatic plant species in field and their responses to gammarid consumption in spring, summer and autumn in a microcosm experiment. We measured the variation of functional traits for each season. The traits selected were those judged most closely related to the allocation of resources to growth or to resistance against herbivores. We clearly established that the strategies of the two species were different and that their consumption rate differed in summer. In summer, E. canadensis allocated more of its resources to structural defence (leaf toughness). The increase in leaf thickness reduced the palatability of E. canadensis, whereas E. nuttallii stimulated its growth. Moreover, a decrease in dry matter content in E. nuttallii was found during the growing season in field. In autumn, both plant species accumulated nitrogen and phosphorus in their tissues. We also demonstrated that neither species induced efficient chemical defences against the herbivores. The different strategies of these two Elodea species could be explained by their different resident times in the introduced area and by an adaptation of the naturalised E. canadensis to herbivores.

Growth of Potamogeton crispus L. from turions in darkness: Implications for restoring submerged plants in eutrophic lakes

In the turbid water of eutrophicated lakes, sunlight becomes the primary limiting factor in restoring submerged plants in such lakes. Potamogeton crispus L., a species of pondweed, is widely used in such restoration because it can be easily propagated through its turions. However, little is known so far of the growth characteristics of turions growing under limited light or even in total darkness. The growth and physiological responses of plants raised from small, medium, or large turions (categorized on the basis of their weight) and growing in total darkness in an aquarium showed that plants raised from small turions were significantly shorter (33.4±4.8cm) than those grown from medium or large turions (49.9±4.3cm and 46.9±7.4cm, respectively; the difference between the two categories was not significant) when measured on the average of 48th, 62nd and 69th days after planting. Although the plant biomass was significantly different among the three groups of turions, it remained virtually the same within each group throughout. Plants raised from the three categories of turions, however, did not differ significantly either in terms of root length or with respect to soluble protein contents and peroxidase activity; the last parameter increased significantly after 48 days in all the three categories, whereas the activity of superoxide dismutase increased significantly after 62 days. These observations indicate that P. crispus plants growing in total darkness suffer from stress due to antioxidants, especially after 48 days of culture. Therefore, it is recommended that larger turions be chosen for planting and that suitable measures be taken to ensure that at least some light reaches the plants 48 days after planting. Three formulas are presented, depending on the level of turbidity and the weight of turions, to calculate the maximum water depth at which P. crispus could survive for restoration of P. crispus in eutrophic lakes.

Adatok a színes békaszőlő (Potamogeton coloratus) hazai előfordulásához

Az európai elterjedésű színes békaszőlő (Potamogeton coloratus) a földrész egyik ritka és veszélyeztetett faja. Hazánkban korábbi adatai főként termálvizes és karsztvizes források kifolyóiból származnak. A bauxitbányászat következtében ezek a Dunántúli-középhegység peremén lévő források elapadtak, a faj a 20. század utolsó évtizedeire eltűnt Magyarországról. A bányászat felhagyását követően a karsztvizek a legtöbb helyen újra felszínre törtek és a faj a korábbi élőhelyein ismét megjelent. A növényt1999 és 2016 között 18 lelőhelyről sikerült újra kimutatni, ezek jelentős részén már az 1900-as évek elején és közepén is gyűjtötték. A színes békaszőlő legtöbb előfordulása a karsztforrásokból került elő, de ezek környékén mesterséges és természetes tavakban is megtalálható.

Distribution and Morphological Variations of Invasive Macrophytes Elodea Nuttallii (Planch.) H. St. John and Elodea Canadensis Michx in Croatia

Abstract The invasive species Elodea nuttallii was recorded for the first time in the Croatian flora in 2006, in the drainage channels of Kopački rit (Baranja). After its establishment, E. nuttallii begins to spread to the eastern and northern part of the drainage channel network from 2006-2009. High water levels are responsible for the linear spreading direction of E. nuttallii, E. nuttallii and E. canadensis show a wide range of morphological variation, which is characteristic of successful invaders. To show morphological variations of two Elodea species, the most important characters indicated in the literature were measured on 24 fresh collected samples from the seven sites in Croatia. In spite of some overlap in leaf length and width between the two Elodea species, the differences of all morphological traits except internode length are statistically significant. In E. nuttallii leaf width, length and internode length show a higher morphological variability as a result of the higher adaptive strategy to environmental parameters. The most reliable morphologi-cal characters distinguishing E. nuttallii and E. canadensis are leaf width 0.5 mm below the tip and the angle at the apex. E. nuttallii can be expected to spread to other areas of Croatia.

Phytomass and Specific Diversity of Macrophyte Vegetation in the Middle Reach of the Yenisei River

Phytomass and specific diversity of macrophytes of the Yenisei River on the stretch from Krasnoyarsk to the mouth of the Angara River were estimated. The investigation showed that littoral macrophyte vegetation clearly differs in specific composition and biomass in the deep water (H>0,8 m) and shallow water (H<0,7 m) zones. Potamogeton lucens principally dominates in deep-water communities; several dominating species are noticed in the shallow-water zone (P.perfoliatus, P.pectinatus, Elodea canadensis and some other species). The average biomass of deep-water macrophytes on the stretch of the river (431±101 g/m2 D.W., n=15, SD) was 2.5 times higher (p<0,01) than the biomass of shallowwater vegetation (172±81 g/m2, n=15). Phytomass loss observed in the two dominating species of pondweed, P. lucens and P.perfoliatus, during the season of vegetation was 3.1±3.4 % (n=17) and 11.6±7.8 % (n=37), respectively. Biomass production of P.lucens ranged from 240 to 630 g/m2, biomass production of P.perfoliatus was 360 g/m2. The estimated Shannon-Margalef index (based on dry biomass) revealed higher specific diversity of the shallow-water macrophyte vegetation as compared to the deep-water one on the majority of sampling sites, but the mean values did not differ statistically (0,90±0,78 и 0,53±0,55, n=15). The biomass and diversity of macrophytes of the Yenisei River did not change considerably at different distances away from the sources of technogenic pollution of the river.

Accumulation of metals in Elodea canadensis and Elodea nuttallii: Implications for plant–macroinvertebrate interactions

Elodea nuttallii and Elodea canadensis are considered good candidates for metal studies. Metal pollution can disturb the interactions between trophic levels. Our goals were 1) to analyse the metal content in plants, sediment and water from three polluted sites, and 2) to analyse the impact of metal contamination on plant consumption by macroinvertebrates. The concentrations of Cd, Cr, Cu, Mn, Ni, Pb, Zn and Fe and S were measured in water, sediment and in the two Elodea species during two years. Our results showed that metal accumulation varied according to site, metal and season. The ability to uptake metal was similar in E. canadensis and in E. nuttallii. No significant seasonal metal accumulation was established for plants or sediment. Metal accumulation in Elodea species in polluted sites had no impact on their palatability. The plant palatability depends on the season and varies according to the part of the plant. In autumn, apex was less consumed than defoliated and foliated stems.