Nymphoides Peltata Research Articles

Epiphytic meiofauna in stands of different submerged macrophytes

Epiphytic meiofauna in association with pure stands of four macrophytes (Nymphoides peltata, Ceratophyllum demersum, Polygonum amphibium and Carex spp.) were studied in the slow-flowing Conakut Channel, within the Kopacki rit floodplain, Croatia, during two vegetation seasons (2001 and 2002). The meiofauna densities for different macrophyte types showed a significant variation between N. peltata and C. demersum stands with a total of 15 meiofauna taxa on the macrophytes. Insect larvae, mostly Chironomidae, and Oligochaeta juveniles were the most abundant taxa recorded during the entire investigated period in all stands of macrophytes, except in P. amphibium.

Adaptive restoration of Nymphoides peltata populations in Lake Kasumigaura from the soil seed bank

Adaptive restoration of Nymphoides peltata populations in Lake Kasumigaura from the soil seed bank

Estimating economic values of vegetation restoration with choice experiments: a case study of an endangered species in Lake Kasumigaura, Japan

As the pace of ecosystem restoration increases, more attention has been directed towards understanding public preferences for ecosystem restoration projects. This paper utilizes a choice experiments technique to evaluate the restoration project of an endangered species, Nymphoides peltata (known locally as asaza) in Lake Kasumigaura, Japan. The restoration project evaluated in this paper consists of two attributes: an extinction risk and a lakeshore ecosystem. First, we observe a positive willingness-to-pay for the vegetation restoration project: the mean willingness-to-pay for restoring the endangered specie and avoiding extinction was about JPY6,800 and the mean willingness-to-pay for restoring the covering area to the ideal condition that the species originally inhabited in 1996 was about JPY1,600. Second, we clarify what kinds of individual characteristics affect preferences for restoration projects compared with preferences for the status quo. The results show that respondents who have strong environmental attitudes, visit experience, high income, and are female are more likely to prefer restoration projects to the status quo. Third, we investigate whether knowledge and comprehension of ecological information have any influence on respondents’ value formations. We find that respondents’ comprehension of ecological information is positively related to their willingness-to-pay for the avoidable level of extinction risk attribute, while respondents’ knowledge of ecological terms has no effect. Overall, our findings suggest that the public strongly desires the avoidance of extinction of endangered species, and indicates that researchers should be careful about how ecological information is given.

An assessment of vegetation and environmental controls in the 1970s of the Mesopotamian wetlands of southern Iraq

A vast ecosystem of wetlands and lakes once covered the Mesopotamian Plain of southern Iraq. Widespread drainage in the 1990s nearly obliterated both components of the landscape. This paper reports the results of a study undertaken in 1972–1975 on the vegetation of the wetlands prior to drainage and provides a unique baseline for gauging future restoration of the wetland ecosystems in Mesopotamia. Five representative study sites were used to assess the flora, three of which were wetlands. A total of 371 plant species were recorded in the five sites, of which approximately 40% represent obligate or facultative wetland species. The wetland vegetation was classified into five major physiognomic forms (submerged, floating, herbaceous tall emergent, herbaceous low emergent and woody low emergent), which was further subdivided into 24 fresh and halophytic communities. Water levels greatly fluctuated across the different types of wetlands, and mean surface water depth ranged from below to greater than 2 m above the sediment surface, reflecting permanently, seasonally or intermittently wet habitats. Aboveground biomass was also highly variable among the communities. The Phragmites australis community, which was the most extensive community type, had the greatest biomass with an average value of approximately 5,000 g m−2 in summer. Distribution and community composition were largely controlled by water levels and saline-freshwater gradients. Canonical correspondence analysis showed that salinity and water depth were the most important factors to explain species distribution. Environmental variables related to soil salinity separated halophytic species in woody low emergent and herbaceous low emergent forms (Tamarix galica, Cressa cretica, Alhagi mannifera, Aeluropus lagopoides, Juncus rigida, and Suaeda vermiculata) from other species. Their habitats were also the driest, and soil organic matter content was lower than those of other species. Habitats with deepest water were dominated by submerged aquatic and floating leaved species such as Nymphoides peltata, Ceratophyllum demersum, and Najas armata. Such diverse environmental conditions in the Mesopotamian wetland would be greatly affected by evapotranspiration, river water inputs from north, ground water inputs, local soil conditions, and a tide or seiche-controlled northward transgression of water from the Gulf. These environmental conditions should be considered in restoration plans if plant communities existed in the mid-1970s are to be part of the desired restoration goals.

The Biology of Invasive Alien Plants in Canada. 10. Nymphoides peltata (S. G. Gmel.) Kuntze

The freshwater aquatic species Nymphoides peltata has been introduced to Canada as an ornamental plant and has been found at sites in Newfoundland, Nova Scotia, Quebec, Ontario and British Columbia. It is currently available through the aquatic nursery trade in Canada and the United States. It may be considered as adventive in Canada since populations readily expand beyond the site of planting, but there is no evidence as yet that it is fully naturalized. In the United States it has naturalized in still or slow-moving waters at widely scattered locations where it replaces native plant communities, changes ecological processes and interferes with human navigation and recreational activities. The short rhizomes over-winter under Canadian conditions, even when complete water drainage results in freezing of the substratum. In its native range, the species has two floral morphs (i.e., is distylous) with a weak incompatibility system, but North American populations usually consist of a single flower morph. A population at Ottawa, ON, has monomorphic flowers with characteristics overlapping between the two Eurasian morphs and has been observed to produce large numbers of viable seeds. Seeds germinate in the spring either on the substratum in shallow water or at the water surface. Seedlings germinating at the water surface may float for several weeks prior to sinking and establishing on the substratum in shallow water. Vigorous stolon production promotes rapid colonization, and vegetative dispersal is readily accomplished through fragmentation of stolons and stems. Key words: Nymphoides peltata, yellow floating-heart, Menyanthaceae, faux nénuphar, NYPPE, weed biology

Macrophytes as indicators and potential remediators in aquatic ecosystems: A case study

The content of macronutrients (N, P, K, Na) and heavy metals (Fe, Mn, Zn, Cu, Ni, Pb, Cd, Co) in plant samples of dominant aquatic macrophytes (Ceratophyllum demersum, Phragmites australis, Trapa natans, Hydrocharis morsus-ranae, Nymphaea alba, Nymphoides peltata, Salvinia natans) from the river Jegricka (Serbia) is presented. Macronutrients content in plant tissue was above necessary limits for plant maximum growth indicating to substantial bioavailability of those elements typical for eutrophic environment. Content of investigated nutrients and heavy metals varied in relation to plant species. Ceratophyllum demersum turned out to be best bioaccumulator for P, K, Fe, Mn, Cu, Ni, Pb, and Co. Salvinia natans accumulated high amounts of N, P, K, Na, and especially Cu and Zn. Nymphaea alba accumulated highest recorded amounts of N and Na. Hydrocharis morsus-ranae accumulated very high amounts of N, P, K, Na, Pb, and Mn. Because of its fast growth, large abundance and homogeneous distribution on this locality, Phragmites australis might have high potential in use for phytoextraction of macronutrients and heavy metals. The application of macrophytes as indicators might be limited depending on the varying of environmental conditions on different localities.

Benthic macroinvertebrates associated with four species of macrophytes

AbstractBenthic macroinvertebrates associated with four species of macrophytes (Nymphoides peltata, Ceratophyllum demersum, Polygonum amphibium and Carex sp.) were investigated during two growing seasons (2001 and 2002) in the slow-flowing Čonakut Channel in the Kopački rit Nature Park in Croatia. A total of 31 macroinvertebrate taxa were found. C. demersum, a submerged plant with dissected leaves, supported the highest macroinvertebrate abundance, almost seven times more than N. peltata, a floating plant with undissected leaves, which harboured the lowest abundance during the research period. Chironomidae larvae (50–83%) and Oligochaeta (14–46%) were the most abundant groups recorded on all macrophyte species. Water-level fluctuation, because of its influence on the appearance and growth of aquatic vegetation, and the trophic state of water within the macrophyte stands seemed to be the main factors which affected the taxonomic composition and abundance of macroinvertebrates.

Invasive crayfish in Europe: the impact of Procambarus clarkii on the littoral community of a Mediterranean lake

Summary1. Despite the growing number of non‐indigenous crayfish species introduced worldwide, little scientific attention has been given to their effects on the recipient communities. Here, we quantified the impact of adult red swamp crayfish (Procambarus clarkii) on key components of the littoral community of a mesotrophic lake in central Italy. We used two densities of crayfish plus a no‐crayfish control, and two complementary methods –in situ enclosures and a laboratory study.2. Both experiments showed that P. clarkii strongly affects the community even at a low density (4 m−2), although a high crayfish density (8 m−2) showed a more pronounced impact in a shorter time.3. In enclosures, P. clarkii quickly consumed the pond snail Haitia acuta, notwithstanding its anti‐predator behaviour, but not the mosquitofish Gambusia affinis. The biomass of the hydrophytes Nymphoides peltata and Potamogeton spp. was strongly reduced by crayfish grazing, coupled with their non‐consumptive plant clipping and uprooting, which were particularly intense in the case of Potamogeton crispus. In contrast, Utricularia australis was avoided by P. clarkii, even when other resources were exhausted.4. The introduction of P. clarkii could reduce biodiversity and increase biotic homogenisation in a short time.

Nymphoides peltata (Gmel.) Kuntze, Myriophyllum spicatum L. and Ceratophyllum demersum L. biomass dynamics in Lake Provala (the Vojvodina Province, Serbia)

Abstract Sixty-five plant species have been found in Lake Provala (the Vojvodina Province, Serbia) and its riparian zone. Among them, three hydrophytes were dominant: Nymphoides peltata, Myriophyllum spicatum and Ceratophyllum demersum. As interactions between different ecological factors, especially light, temperature and nutrient level, are of prime importance for productivity of macrophytes, we analyzed the main physical and chemical indicators of water quality in the studied location. In the vegetation period of the year 2000, the dominant hydrophytes were analyzed for biomass production dynamics in the studied aquatic ecosystem, including fresh weight (FW), dry weight (DW) and ash free dry weight (AFDW). The studied plant species achieved maximum biomass production in June, with statistical differences among the species at the significance level of α = 0.05.

Interference between two floating-leaved aquatic plants: Nymphoides peltata and Trapa bispinosa

A 12-week microcosm experiment was conducted to identify the intraspecific and interspecific interference abilities of two floating-leaved aquatic plants Nymphoides peltata (Gmel.) O. Kuntze and Trapa bispinosa Roxburgh. N. peltata exerted a strong interspecific interferential effect on T. bispinosa, but the opposite was not apparent. There existed an intraspecific interferential effect of T. bispinosa on itself, although the interspecific interference of N. peltata was stronger. No apparent intraspecific interference was found among the individual plants of N. peltata. The removal of N. peltata had a positive impact on growth and performance of T. bispinosa, whereas no apparent impacts were found in the removal of T. bispinosa on growth and performance of N. peltata. Moreover, both the removal of N. peltata and T. bispinosa did not show apparent effects on growth of the remaining individuals of the species themselves. These results suggest that N. peltata has distinct interferential advantages over T. bispinosa and that this depends mainly upon the differences between the two species in morphology and life history.

Reproduction strategies in introduced Nymphoides peltata populations revealed by genetic markers

To determine whether introduced Nymphoides peltata populations reproduced vegetatively or sexually, microsatellites were used to study the genetic structure of the species in Sweden. Leaves from 156 plants and seeds from 4 plants were sampled from 7 water-systems and analysed. A total of 10 genotypes were found among the 156 leaves. Seeds accounted for one additional genotype per seed. Lack of genetic variation and entirely vegetative reproduction dominated in the introduced N. peltata populations although sexual reproduction was found in one water-system. However, even where the species reproduced sexually, vegetative reproduction constituted an important part of the total reproduction.

Growth of three submerged plants below different densities of Nymphoides peltata (S. G. Gmel.) Kuntze

We evaluated one-sided competition from the floating-leaved plant Nymphoides peltata (non-indigenous in Sweden) on three submerged plant species, Ceratophyllum demersum, Elodea canadensis and Ranunculus circinatus, in a controlled experiment. The three submerged species were allowed to grow for 21 days in the absence of N. peltata and with the species present at densities of approximately 33, 66 and 100% cover. All species retained a positive relative growth rate (RGR) based on length at all N. peltata densities, but responded with negative growth based on weight for several treatments. C. demersum achieved RGR of 0.03 day −1 in the absence of N. peltata, RGR of 0.02 day −1 in the lowest N. peltata density but negative RGR in the two denser treatments. E. canadensis responded similarly with RGR of 0.04 day −1 in the absence of N. peltata, RGR of 0.01 day −1 in the lowest N. peltata density and negative RGR in the two denser treatments. R. circinatus, on the other hand, never achieved positive RGR based on weight. These results suggest that one-sided competition from floating-leaved plants has a profound effect on the submerged plant community.

Plastic and Non-Plastic Variation in Clonal Morphology of Nymphoides peltata along a Water Depth Gradient in Liangzi Lake, China

ABSTRACT The importance of plastic responses to water depth as compared to non-plastic (developmental) changes in clonal morphology of the floating-leaved macrophyte Nymphoides peltata was examined in an outdoor pond experiment. All investigated clone characteristics, including clone weight and ramet number, had maximum values demonstrating optimal clonal growth at water depth of about 60 cm. Beyond the depth of 60 cm, these growth parameters were increasingly less than optimal. Biomass allocation to petioles of clones gradually increased with depth at the expense of allocation to roots. At the individual ramet level, most characteristics exhibited significant plastic responses to water depth. N. peltata seemed to be more plastic in the elongation of leaf petioles than in other organs in response to water depth. In addition, many ramet characteristics showed a significant non-plastic variation, with some characteristics changing with clone size irrespective of water depth. However, ramet weight and petiole length had no significant variation in shallow water, while they dramatically decreased among generations in deep water.

Exogenous polyamines enhance copper tolerance of Nymphoides peltatum

The protective effects of polyamines (PAs) against copper (Cu) toxicity were investigated in the leaves of Nymphoides peltatum. Cu treatment increased the putrescine (Put) level and lowered spermidine (Spd) and spermine (Spm) levels, thereby reducing the (Spd+Spm)/Put ratio in leaves. Exogenous application of Spd or Spm markedly reversed these Cu-induced effects for all three PAs and partially restored the (Spd+Spm)/Put ratio in leaves. It also significantly enhanced the level of proline, retarded the loss of soluble protein, decreased the rate of O2*- generation and H2O2 content, and prevented Cu-induced lipid peroxidation. Furthermore, exogenous Spd and Spm reduced the accumulation of Cu and effectively maintained the balance of nutrient elements in plant leaves under Cu stress. These results suggest that exogenous application of Spd or Spm can enhance the tolerance of N. peltatum to Cu by increasing the levels of endogenous Spd and Spm as well as the (Spd+Spm)/Put ratio.

Restoration of genetic diversity from soil seed banks in a threatened aquatic plant, Nymphoides peltata

Populations of a threatened aquatic plant, Nymphoides peltata, have rapidly degenerated under the influence of recent artificial changes in Lake Kasumigaura of Japan. To estimate the potential of soil seed banks for genetic restoration of the species, we used 10 microsatellite markers to analyze the genetic variation in adults and in seedlings that emerged from soil seed banks. About 187 leaf samples from the cultured stocks that were collected in 17 adult subpopulations in 1995 and 2000 and from three subpopulations that were newly discovered in 2002 were analyzed. As a result, only 18 genets could be identified, suggesting that clonal diversity of the adult population had already become extremely low. Genetic tests were performed on 430 seedlings from seed banks at six locations of natural lakeshores and three of the restoration sites that were artificially constructed in an attempt to assign them to the remnant adult population; many of the seedlings showed genetic variation different from the adults. Furthermore, the seedlings preserved seven alleles that had been lost from remnant adults. However, they had lower average numbers of alleles and heterozygosity levels (NA = 1.5–3.1, H E = 0.146–0.487) than the remnant adults (NA = 3.5, H E = 0.539) and showed high inbreeding coefficients, suggesting that the seed banks were produced by inbreeding. Thus, although the seed banks had a certain potential to restore genetic diversity, the fitness reduction in seed banks caused by inbreeding could affect the success of restoration based on seed banks.

Competitive Performance of Nymphoides Peltata (Gmel.) O. Kuntze Growing in Microcosm

Two experiments were conducted to investigate the effects of competition on growth and performance of Nymphoides peltata (Gmel.) O. Kuntze in microcosm. Part of the research on growth and biomass allocation of N. peltata in response to competition had been reported early (Wu, Z. & D. Yu, 2004, Hydrobiologia 527: 241–250). This paper focuses on the morphological variations of N. peltata under competitive pressure. First, competition between N. peltata and Zizania latifolia (Griseb.) Turcz. ex Stapf. was assigned with the densities of N. peltata to Z. latifolia ratios of 4:0, 4:2, 4:4 and 4:8. Water surface coverage, surface area per leaf blade and number of leaves per plant of N. peltata all declined significantly with increasing density of competitor. Similar results were also found for petiole length and density of branching. However, the variations of planting density did not significantly affect the number of ramets per plant and the stolon length of N. peltata. Second, competitions between N. peltata and emerged Z. latifolia, floating-leaved Trapa bispinosa Roxb. and submerged Myriophyllum spicatum L. were also studied simultaneously. The results showed that significant difference was only found for the water surface coverage of N. peltata. No other significant differences were found for the number of ramets per plant, number of leaves per plant, density of branching, surface area per leaf blade, petiole length, and stolon length of N. peltata. Our studies indicate that N. peltata presents morphological variations when it is growing with Z. latifolia, such that the growth of above-ground parts decrease (i.e., leaf number, petiole length, branching density) and the growth of below-ground parts remains stable (i.e., stolons length). However, N. peltata does not show apparent differences in morphology when it is growing with T. bispinosa or M. spicatum. Accordingly, we conclude that the growth of N. peltata may be apparently inhibited by the presence of Z. latifolia, while T. bispinosa and M. spicatum may have little impact on the growth and performance of N. peltata.

Influence of inbreeding depression on a lake population of Nymphoides peltata after restoration from the soil seed bank

The negative effects of inbreeding depression on fragmented small populations are likely to be expressed more strongly after restoration efforts if regeneration processes have been highly restricted in degraded habitats. We examined the potential influences of inbreeding depression on a population of Nymphoides peltata (Menyanthaceae) restored from the remnant soil seed bank. A hand-pollination experiment demonstrated self-compatibility of a single remaining homostyle genet and significant inbreeding depression in selfed progeny, especially in parameters related to seedling growth (\(\updelta=0.5\)–0.6 for biomass, and \(\updelta=0.3\)–0.4 for relative growth rate). Our genetic analysis indicated that the presumed number of parents contributing to the current soil seed bank was only 2–8 genets and that a single sib-family dominated at each of three sampling sites. The results also showed that the selfed progeny of the homostyle genet were overwhelmingly dominant at two sites (86.8 and 94.7%). As a result, the growth performance of the seed bank seedlings was significantly reduced, to a level as low as that of the selfed progeny. Active restoration efforts to minimize the negative effects of the genetic bottleneck and continuous monitoring based on genetic and demographic study are recommended.

Safe sites for establishment of Nymphoides peltata seedlings for recovering the population from the soil seed bank

AbstractThe population of the endangered plant species Nymphoides peltata in Lake Kasumigaura, Japan, has been declining drastically recently, and seedlings that emerge from the remaining soil seed bank have entirely failed to establish. The decline has followed artificial control of the water level in the lake. To examine the environmental requirements at the seedling establishment stage, we investigated the survival and growth of emerged seedlings at various microsites on the lakeshore by manipulating environmental conditions such as exposure to waves, inundation, and light availability so as to include the conditions of the presumed safe sites. Seedling survival at the early stage was affected most by environmental variables relating to the susceptibility to inundation. Survival until seedling establishment was profoundly affected by light availability as well as by susceptibility to inundation. In all, 136 genets were established in quadrats less prone to inundation and with sufficient light availability, which is consistent with the presumed safe‐site characteristics of the original water regime: bare ground exposed during the spring water‐level drawdown. Recovering the original water regime with seasonal drawdown will be indispensable for recovering a self‐sustainable population. However, as first‐aid measures, active restoration efforts through adaptive management using the remnant soil seed bank are urgently needed before the soil seed bank becomes exhausted.

Isolation and characterization of highly polymorphic microsatellites in the aquatic plant, Nymphoides peltata (Menyanthaceae)

AbstractTen microsatellite loci were described for conservation design of a threatened clonal aquatic plant, Nymphoides peltata. The microsatellite loci obtained through the construction of an enriched library were polymorphic (2–6 alleles per locus) and exhibited high levels of observed (0.333–0.889) and expected (0.284–0.765) heterozygosities. All microsatellite loci were expected to be useful for identification of genets and evaluation of genetic diversity of this species.

Reproductive consequences of interactions between clonal growth and sexual reproduction in Nymphoides peltata: a distylous aquatic plant

Distyly is a sexual polymorphism in which plant populations contain two floral morphs differing in morphology and physiology. The dimorphism serves to promote animal-mediated cross-pollination between the floral morphs. Clonal propagation can interfere with the functioning of distyly by compromising intermorph pollinations, resulting in reduced fertility. Here, we investigate the relations between clonal growth and sexual reproduction in the aquatic macrophyte Nymphoides peltata (Menyanthaceae). Surveys of morph representation in 30 populations from five regions of China revealed that most populations exhibited strongly biased morph ratios and 30% contained a single floral morph. Experimental pollinations indicate that N. peltata possesses a strong dimorphic incompatibility system preventing self and intramorph fertilizations. An experiment involving the manipulation of morph ratios in an experimental population and an investigation in a natural population with strong morph substructure both provided evidence that compatible pollen dilution limits fertility. Despite constraints on the functioning of distyly in N. peltata we found no evidence for evolutionary changes to the heterostylous syndrome, as reported in Nymphoides, including populations of N. peltata in other parts of its geographical range.