Amblystegium Riparium Research Articles

Hydrologic alteration affects aquatic plant assemblages in an arid-land river

Abstract We evaluated the effects of long-term flow alteration on primary-producer assemblages. In 1962, Flaming Gorge Dam was constructed on the Green River. The Yampa River has remained an unregulated hydrologically variable river that joins the Green River 100 km downstream from Flaming Gorge Dam. In the 1960s before dam construction only sparse occurrences of two macroalgae, Cladophora and Chara, and no submerged vascular plants were recorded in the Green and Yampa rivers. In 2009–2010, aquatic plants were abundant and widespread in the Green River from the dam downstream to the confluence with the Yampa River. The assemblage consisted of six vascular species, Elodea canadensis, Myriophyllum sibiricum, Nasturtium officinale, Potamogeton crispus, Potamogeton pectinatus, and Ranunculus aquatilis, the macroalgae Chara and Cladophora, and the bryophyte, Amblystegium riparium. In the Green River downstream from the Yampa River, and in the Yampa River, only sparse patches of Chara and Cladophora growing in ...

Bentoso dumblių bendrijos skirtingos vandens kokybės Lietuvos upėse

Straipsnyje pateikti 2004–2006 m. duomenys apie bentoso dumblių bendrijas skirtingos vandens kokybės Lietuvos upėse. Skirtingos vandens kokybės upėse daugiausia dominuoja Cladophora glomerata–Vaucheria sessilis–Fontinalis antipyretica dumblių samanų bendrija. Skirtingos vandens kokybės upių būklę geriau rodo bendrijose vietomis gausiai besivystančios dumblių rūšys. Švarių vandens telkinių – Hildenbrandia rivularis, Audouinella chalybea ir A. hermanii; mažai užterštų – Vaucheria sessilis ir Fontinalis antipyretica; vidutiniškai užterštų Stigeoclonium nanum, S. tenue, Aulacoseira islandica ir Melosira varians. Skirtingos vandens kokybės ir atskirų upių išilginiame pjūvyje bentoso dumblių bendrijų struktūra kito. Tai galėjo lemti substrato heterogeniškumas, vandens tekėjimo greičio, upės gylio, šviesos intensyvumo bei pagrindinių biogenų koncentracijos pokyčiai.

Variations of aquatic bryophyte assemblages in the Rhine Rift related to water quality. 1. The Alsatian Rhine floodplain

A survey of the relationships between aquatic bryophyte assemblages and water trophic level was performed in the Rhine alluvial floodplain in Alsace (France). Ten strictly aquatic bryophyte species showed mostly monotonic relationships with N-NH4 +, P-PO4 3- and water temperature. They segregated along the first axis of a principal components analysis whose site scores were significantly correlated with the logarithms of the means of [N-NH4 +] and with the standard deviation of temperature at p < 0.0001, with the logarithm of the means of [P-PO4 3-] and with the means of [N-NO3 -] at p < 0.001, and with the standard deviation of [P-PO4 3-] at p < 0.05. Chiloscyphus pallescens, Pellia endiviifolia and Amblystegium tenax showed an oligotrophic status in Alsace as opposed to Amblystegium fluviatile, Cinclidotus danubicus, C. riparius and Fissidens crassipes. Amblystegium riparium, Fontinalis antipyretica and Rhynchostegium riparioides exhibited a very broad trophic range but occurred more often in eutrophic streams. The trophic ranges of these species in Alsace are compared with those found in other areas and the differences are discussed.

A macrophyte communities sequence as an indicator of eutrophication and acidification levels in weakly mineralised streams in north-eastern France

The Northern Vosges streams are subjected to acidification upstream and to eutrophication downstream. A bio-indicator scale of the degree of eutrophication and of the level of acidification, based on four aquatic macrophyte communities, was established in these weakly mineralized streams. Aquatic plant communities therefore begin as Group A, develop into Group B and become Group C or D downstream. The A community was characterized by bryophytes (Scapania undulata, Sphagnum sp.) and Potamogeton polygonifolius in oligotrophic, acidified to weakly acidified, and poorly buffered streams. The B community, defined by P. polygonifolius and the appearance of Ranunculus peltatus and Callitriche species (C. platycarpa, C. hamulata) was found in oligotrophic waters with a higher buffer capacity than the A community. The C community was determined by the disappearance of P. polygonifolius and the appearance of Elodea species (E. canadensis, E. nuttallii) and rare species in mesotrophic and neutral streams. The D community, with very high nutrient loading, was characterized by the abundance of Callitriche obtusangula, by the presence of Amblystegium riparium, Fissidens crassipes and the development of filamentous algae. This macrophyte sequence corresponded to an upstream to downstream zonation, which was characterized by an increase in buffer capacity and in nutrient levels and a decrease in protons and aluminium load.

Trophic Response Curves of Aquatic Bryophytes in Lowland Calcareous Streams

Logistic regression was used to model the response curves of seven aquatic bryophyte species from calcareous lowland streams of two hydrographic networks. Almost all the species exhibited log-normal response curves and significant optima when the data coming from the two hydrographic networks were simultaneously considered, but monotonic response curves within each of the hydrographic networks. The response curves of Amblystegium riparium in the Walloon hydrographic network, in the Alsatian hydrographic network, and in both networks considered simultaneously, showed a strong overlap. Conversely, Amblystegium fluviatile showed distinctly different response curves between the studied hydrographic networks. This was also the case for A. tenax, Fissidens crassipes, and Fontinalis antipyretica. Amblystegium tenax has a typical oligotrophic status in the Alsatian floodplain, but in the Walloon hydrographic network, is still present in the most polluted waters whose annual mean concentrations of N-NH4+ can reach up to 9,000 pIg 1-'. Amblystegium fluviatile and Fontinalis antipyretica presented similar response patterns, exhibiting optima in eutrophic waters when the data from the two hydrographic networks were simultaneously considered, but reaching maximal occurrence in the most oligotrophic waters in the Walloon hydrographic network. It is suggested that these species might include several ecotypes with different trophic requirements. Concern over the impact of nutrients on rivers in Europe has increased since the publication of the European Community's Urban Wastewater Treatment Directive (Kelly 1998). It was demonstrated that the natural geochemical content of P-PO43in the large European rivers is of ca 10 pxg 1-', but that it is commonly 10 to 100 times greater in most of the rivers due to anthropogenic eutrophication (Carbiener et al. 1995). Despite efficient urban and industrial discharge sanitation policies, and a great deal of campaign information on the dangers of abusive mineral fertilizer use, the waters of most of the rivers have not as yet recovered the chemical quality they had at the end of the last century. This has been shown by long term monitoring studies in rivers such as the Seine or the Marne (France), where the oxidation of ammonium into nitrates causes nitrogen concentrations to increase further (Cun et al. 1997). The great interest that developed with problems due to nutrient enrichment focused research on eutrophication and has involved a rapid increase in biological methods for monitoring nutrients (see Kelly & Whitton 1998 for review). Weighted averaging is an easy quantitative method for predicting values of an environmental variable from species composition, by averaging the indicator values of species that are present (Ellenberg et al. 1991). The estimation of the species indicator values can be empirically derived or averaged over the values of the environmental variable for the samples in which a species occurs (e.g., Empain 1977; Haury et al. 1996; Kelly 1998). This may, however, give misleading results if the investigated species present a broad ecological range and if the distribution of the environmental variable is not homogeneous over the whole range of occurrence of the species (Ter Braak & Looman 1986). Another alternative to define species indicator values is to estimate the species optimum by fitting a curve to the species data by regression. In the case of presence-absence data, the logistic regression fits a curve giving the probability of occurrence of a species as a function of a given environmental factor. Such a technique was already employed to determine diatoms ecological optima and tolerances used in calibration methods for inferring past chemistry of lake waters (Birks et al. 1990; Oksanen et al. 1988). In aquatic bryophytes, the species response curves have not yet been investigated. The ecophysiological processes explaining their reaction to nutrients remain poorly understood (Bates 1992) and, except for some experimental work (Frahm 1975, 1976; Steinman 1994) and correlative sur0007-2745/99/720-728$1.05/0 This content downloaded from 207.46.13.75 on Fri, 08 Jul 2016 05:28:12 UTC All use subject to http://about.jstor.org/terms 1999] VANDERPOORTEN & DURWAEL: RESPONSE CURVES 721 veys on the relationships between aquatic bryophytes and water trophic level (Vanderpoorten 1999a; Vanderpoorten et al. 1999), few studies have yet been conducted. Hence, Duill (1991) gave no information concerning the trophic requirements of aquatic mosses in the ecological index system of central Europe. The aim of this paper is to 1) model the response curves of aquatic bryophytes from hard lowland running waters along gradients of N-NHjand PPO4-, covering the entire range of the species using logistic regression to provide precise autoecological data on their trophic requirements, 2) calculate species optima and tolerances to these factors in order to provide a basis for simple methods of survey of water trophic level, and 3) compare the species response curves between two different hydrographic networks to investigate the extent to which the species exhibit similar response curves between the basins, and therefore to assess whether methods of biomonitoring based on species optima are transposable from an area to another.

Effects of fish farm pollution on phytocenoses in an acidic river (the River Scorff, South Brittany, France)

Summary Effects of fish farm pollution were assessed by comparing upstream and downstream vegetation from three fish farms on the Scorff River system (Southern Brittany). Changes in the occurrence of several species including vascular plants and bryophytes (Myriophyllum alterniflorum, Octodice- ras fontanum), as well as overall variations of species abundance (increase in cover for Amblystegium riparium, Callitriche hamulata, C. obtusangula and decrease in cover for Scapania undulata, Chiloscyphus polyanthos, Ranunculus penicillatus) were observed. Principal Component Analysis showed the importance of physical features in governing distribution and cover of macrophytes for such a disturbance. The ecological response of the vegetation was greater in swifter and shallower reaches (or stretches) than in lower and deeper ones. A particular study of seven species led to the analysis of the respective impact of physical features and pollution on the distribution of species.

Interspecific differences in Zn, Cd and Pb accumulation by freshwater algae and bryophytes

The relationships between the concentrations of zinc, cadmium and lead in aquatic plants and the concentrations of these metals in the ambient water have been compared for three algae (Lemanea fluviatilis, Cladophora glomerata, Stigeoclonium tenue), one liverwort (Scapania undulata) and three mosses (Amblystegium riparium, Fontinalis antipyretica, Rhynchostegium riparioides). The data to establish these relationships are all based on our own studies, some published already, some here for the first time. They come from a wide range of streams and rivers in Belgium, France, Germany, Ireland, Italy and the U.K. There were significant bivariate positive relationships between concentrations of Zn, Cd and Pb in water and plant for all species except Cd and Pb in Stigeoclonium tenue. When relationships were compared using datasets with total or filtrable metals in water, most differences were slight. However there were marked differences both between species and between metals. Comparison for the seven species of Zn in the plant when aqueous Zn is 0.01 mg l−1, a concentration at which all seven were found, shows that the four bryophytes had the highest concentrations; however the two green algae had steeper slopes (representing change in concentration in plant in response to change in aqueous concentration). Lemanea fluviatilis had a slope closer to that of the bryophytes, but the concentration was about one order of magnitude lower. All seven species were found at a concentration of 0.01 mg l−1 Pb, and at this concentration there were almost two orders of magnitude difference between the species which accumulated the most (Scapania undulata) and the one which accumulated the least (Cladophora glomerata). The steepest slope was however shown by C. glomerata.

Macrophytes of the River Wear: 1966, 1976, 1986

Summary A survey was made during 1986 of the longitudinal distribution of macrophytes in the River Wear (N-E. England) in order to make comparisons with surveys in 1966 and 1976. The presence or absence of species recognizable with the naked eye was recorded in 1986 for 74 of the possible 211 0.5-km lengths of river. In contrast to the marked differences between 1966 and 1976, changes since 1976 were minor; many were probably merely a reflection of recent flow events. The most clear-cut difference was the loss of most of the Elodea canadensis population. The only other change in records which may reflect a longer-term environmental change was a marked increase in the moss Amblystegium riparium, a species characteristically associated with organic pollution.

Impact of heavy metal waste leachates on a stream in South-West France

An account is given of the impact of leachates from two adjacent solid waste disposal sites on a receiving stream in south-west France. The wastes originate from a zinc smelter and an associated chemical works. The first leachate, which contained elevated concentrations of zinc, cadmium and sulphate caused a marked change and reduction in the flora of the receiving stream. After entry of the second leachate, which contained very high concentrations of dissolved barium, a thick precipitate of barium sulphate covered the stream bottom, causing a further reduction in both number and amount of photosynthetic species. The aquatic moss Amblystegium riparium was the dominant organism below both sources of contamination, and its possible use as a monitor of heavy metal concentrations in the stream system is discussed.

Accumulation of heavy metals by aquatic mosses. 3: Seasonal changes

The changes taking place at seven stream and river sites over a 14-month period were followed for the following: 1) % cover of Rhynchostegium riparioides; 2) relative abundance of Rhynchostegium as part of the whole plant community and, where present, also Amblystegium riparium and Fontinalis antipyretica; 3) 18 water chemistry variables; 4) concentrations of nine metals in 2-cm tips of Rhynchostegium at all sites and of Amblystegium and Fontinalis at one site each.

Ultrastructure of Sporogenesis in the Moss, Amblystegium riparium. I. Meiosis and Cytokinesis

Emphasis is placed on three aspects of meiosis in the moss Amblystegium riparium (Hedw.) BSG: 1***) nature of the sporogenous layer; 2) prophasic microtubules and polarity; and 3) cleavage pattern. Spore tetrads develop while still encased by archesporial cell walls. The cellular nature of the sporogenous layer differs from the more usual occurrence of free sporocytes released into a common spore sac. Two important events mark the establishment of sporocyte polarity during meiotic prophase: 1) migration of the four plastids to the distal tetrad poles (telophase II poles); and 2) ingrowth of the sporocyte wall in eventual cleavage planes between the tetrad poles. An extensive, plastid-based microtubule system is associated with organelle migration during the establishment of sporocyte polarity in meiotic prophase. Disruption of the nuclear envelope in prometaphase I occurs at sites opposite the four plastids where microtubules extend from plastid envelope to nuclear envelope. Formation of a cell plate following the first meiotic division results in a dyad, whereas in many mosses meiosis is completed in the undivided sporocyte and is followed by simultaneous cleavage into a spore tetrad. Spore cleavage is accomplished by vesicular coalescence resulting in septa that coincide with the prophasic wall ingrowths.

ULTRASTRUCTURE OF SPOROGENESIS IN THE MOSS, AMBLYSTEGIUM RIPARIUM I. MEIOSIS AND CYTOKINESIS

Emphasis is placed on three aspects of meiosis in the moss Amblystegium riparium (Hedw.) BSG: 1***) nature of the sporogenous layer; 2) prophasic microtubules and polarity; and 3) cleavage pattern. Spore tetrads develop while still encased by archesporial cell walls. The cellular nature of the sporogenous layer differs from the more usual occurrence of free sporocytes released into a common spore sac. Two important events mark the establishment of sporocyte polarity during meiotic prophase: 1) migration of the four plastids to the distal tetrad poles (telophase II poles); and 2) ingrowth of the sporocyte wall in eventual cleavage planes between the tetrad poles. An extensive, plastid‐based microtubule system is associated with organelle migration during the establishment of sporocyte polarity in meiotic prophase. Disruption of the nuclear envelope in prometaphase I occurs at sites opposite the four plastids where microtubules extend from plastid envelope to nuclear envelope. Formation of a cell plate following the first meiotic division results in a dyad, whereas in many mosses meiosis is completed in the undivided sporocyte and is followed by simultaneous cleavage into a spore tetrad. Spore cleavage is accomplished by vesicular coalescence resulting in septa that coincide with the prophasic wall ingrowths.

Amblystegium riparium New to New Mexico

Several aquatic pleurocarpous mosses were collected in Taos and Sandoval Counties, New Mexico, while searching for Fontinalis. Of these, Amblystegium riparium (Hedw.) B.S.G. is new to New Mexico, but was to be expected because of its presence in Arizona (Haring 1961). These New Mexico populations belong to fo. longifolium (Schultz) Moenk., whereas the Arizona populations belong to var. brachyphyllum (Card. & Th&r.) Grout and fo. fluitans (Lesq. & James) Grout. These distinctions may be meaningless because of the recognized variability of the species (Conard 1959).

Aquatic mosses as monitors of heavy metal contamination in the river etherow, great britain

The use of aquatic mosses to monitor heavy metals was investigated in the River Etherow, near Manchester, Great Britain. The river was visited on five occasions during 1979 and 1980 and samples of water, sediment and submerged aquatic moss were analysed for heavy metals. Zinc in particular was an important pollutant in this river, sometimes exceeding 0·5mg litre −1 in the water. Significant positive correlations were found between concentrations of zinc in water and the terminal 2 cm shoot tips of Fontinalis squamosa and Rhynchostegium riparioides, suggesting that these species may be useful as monitors of zinc contamination in rivers. Data were also obtained for Amblystegium riparium and Fontinalis antipyretica, but these were not sufficiently widespread to enable their value as monitors to be assessed. Although chromium was not detected in the water (<0·01 mg litre −1), detectable concentrations were found in mosses from some sites, suggesting the occurence of intermittent sources of this metal.

Temperature Related Growth Patterns in Amblystegium riparium

Freshly collected Amblystegium riparium (Hedw.) B.S.G. plants were grown submersed at various temperatures ranging from 6 to 330C. Peak growth rates occurred at 230C and death at 330C. Response curves for main axis elongation, lateral branch formation, branch elongation and reproductive branch formation differed in shape, and elongation rates changed over time. Lateral branch growth of branches initiated later was lower than growth of branches initiated earlier in the experiment. High temperature stress resulted in a proliferation of branches. Branch and main axis apices appeared to be the most heat resistant parts of the plants. Amblystegium riparium (Hedw.) B.S.G. (Leptodictyum riparium (Hedw.) Warnst.) is typically found submerged in streams but can grow on wet soils. The type specimen was collected in the Thames River, England, and the species is found widely distrib- uted in the United States (Grout, 1928; Lawton, 1971). Taxonomic relationships of Amblystegium riparium were investigated by Conard (1959). Ecological relationships have received little attention, other than what may be found in floristic studies. An interesting ecological phenomenon in relation to this moss was observed in the Al- exandra Botanic Garden located at Wellesley College, Wellesley, Massachusetts. Am- blystegium riparium grows abundantly in a small artificial stream which extends ca. 400 m within the botanical garden; however the moss is found only in the upper 200 m of the stream. The stream, fed by well water from a stand pipe at the stream origin, was constructed in a naturalistic style with alternating pools, riffles and small (10-20 cm) water falls. The latter habitats, formed by rocks anchored in the cement bottom, are the most common location at which the moss may be found. Since the stream channel is sealed by cement there are no differences in substrate which can explain the lack of the moss in the lower section of the stream. Many sites exist in the lower section which are similar in exposure and current velocity to sites supporting moss growth in the upper section. While biotic factors such as competition can not be excluded as having a role in preventing growth of the moss in the lower section, the distribution patterns of other organisms do not form convincing evidence that such factors are highly important. Since the stream has only one source of water and flows only a short distance, one would suspect that abiotic factors, such as water chemistry, would be relatively con- stant. An analysis of 20 chemical parameters demonstrated little difference in water chemistry. Two factors were discovered which did change significantly along the stream, carbon dioxide concentrations and temperature. This paper represents prelim-

Untersuchungen des CO2–Stoffwechsels submerser höherer Wasserpflanzen im Fließgewässer unter Einsatz eines fahrbaren Infrarot‐Gasanalysator‐Labors

Investigations on the CO2 Balance of Submerged Water Plants in Running Water By Means of a Motile Laboratory for Infrared Gas AnalysisThe CO2‐balance of the submerged water mosses Hygrohypnum ochraceum f. obtusifolia, Amblystegium riparium, Amblystegium riparium f. fontinaloides and of Potamogeton trichoides (Potamogetonaceae) was investigated by means of a transportable laboratory for infrared gas analysis. The experiments were carried out in the river Zwickauer Mulde by means of glass vessels exposed to the water body. The device for continuous measuring CO2 exchange was operated by pumping air through the vessels containing 4 l of water. The water plants exhibited a distinct day night rhythm of CO2 turnover. In some cases river water alone, which had percolated a tampon of Perlon fibres, also showed a considerable day night rhythm of CO2 turnover which had to be attributed to phytoplankton and suspended periphyton organisms, the activity of which is superimposed above the photosynthetic activity of the macrophytes. Measurement of the CO2 balance of submerged plants in water containing microphytes can only be attributable to the macrophytes if the time of exposition does not exceed one day.

Mosses of Utah New to Science

Mosses of Utah New to Science

GROWTH AND SEXUAL REPRODUCTION OF THE MOSS AMBLYSTEGIUM RIPARIUM UNDER STERILE CONDITIONS

Belkengren, R. O. (Oregon State U., Corvallis.) Growth and sexual reproduction of the moss Amblystegium riparium under sterile conditions. Amer. Jour. Bot. 49(6): 567–571. Illus. 1962.—Growth of Amblystegium riparium as primary or secondary protonemata, or as a leafy gametophyte under aseptic conditions, is reported. Yeast extract appears to be inhibitory for shoot growth but not for protonemal growth; it appears to cause the death of shoot buds on protonemata before they differentiate into leafy shoots, so that the organism grows as protonema only. Sexual reproduction of this organism in continuously illuminated cultures was induced by a CO2‐free period followed by addition of CO2 or sugar. Senescence in a culture may also induce sporophyte formation presumably by interfering with photosynthesis or some other function.