Abundance Of Aquatic Macrophytes Research Articles

Stable or changing lakes? a classification of aquatic macrophyte assemblages from a eutrophic shallow lake system in the United Kingdom

1. It is proposed that an appreciation of patterns of change and stability in macrophyte floras is an important tool for lake managers. 2. The presence and abundance of aquatic macrophytes was annually monitored (from 1983 to 1995) along permanent transects in 13 shallow lakes in the Broads wetland in eastern England, United Kingdom. 3. Cluster analysis (TWINSPAN) revealed three Broad Macrophyte Types (BMTs) or assemblages. Two of these were sub-divided into four and then again into six sub-types. BMT1 had a constant presence (i.e. in more than 60% of all samples) of charophytes, Potamogeton pectinatus L.,Myriophyllum spicatum L. and Najas marina L. BMT2 had a constant presence of Nuphar lutea (L.) Smith and filamentous algae. BMT3 consisted of sites without macrophytes. 4. The BMTs provided a useful regional classification for aquatic vegetation in shallow, calcareous, and slightly brackish lakes with relatively organic sediments. The BMTs were compared with national and international classifications. The value of BMTs as conservation targets was assessed. 5. Analysis of changes of macrophyte assemblages with time, using ordination (CANOCO) and time-series plots, revealed lakes with stable, drifting, or erratic and unstable macrophyte assemblages. 6. The method of presentation used facilitates the interpretation of year-to-year macrophyte changes. The implication is that management effort can be more effectively directed towards conservation targets. The effects of management on the aquatic flora, such as dredging and biomanipulation, were shown to be easily evaluated using Cockshoot Broad as an example. © 1998 John Wiley & Sons, Ltd.

Community Structure of Lake St. Clair Fishes Based Upon Catchability Studies from 1977 to 1988

Two fish communities, based upon species co-occurrences, were identified in Lake St. Clair. These may be broadly classified as a patchy water community (associated with an abundance of aquatic macrophytes) and an open water community. Centrarchids dominated the patchy water community, while species from the Catostomidae, Percidae, Sciaenidae, and Percichthyidae were most abundant in the open water community. The most ubiquitous species sampled over the 12 years of the study were: channel catfish ( Ictalurus punctatus), rock bass ( Ambloplites rupestris), walleye ( Stizostedion vitreum), and freshwater drum ( Aplodinotus grunniens). Species diversity was greatest in the patchy water community, represented by a single collection site, Mitchells Bay. The three more southerly collection sites, St. Lukes, Tremblay Creek, and Puce Creek, had greater similarities in species composition to each other than they did to Mitchells Bay. However, during high water level years, species composition among all collection sites was more similar.

Limnological Factors Influencing Bird Abundance and Species Richness on Florida Lakes

ABSTRACT Forty-six bird species were observed on 33 Florida lakes with some species occurring on only one lake and others on as many as 26 lakes. Average annual bird abundance ranged from seven to 750 bird/km2 and total species richness ranged from two to 30 species per lake. Regression analyses were used to examine the effects of lake trophic status, aquatic macrophyte abundance, and lake morphology on average annual bird abundance and total species richness. All trophic state parameters (total phosphorus, total chlorophyll a, etc.) accounted for significant portions of the variance in average annual bird abundance, but total chlorophyll a concentrations (μg/L) accounted for the highest percentage (47 percent) of the variance. The best fit regression equation was: Log Bird Abundance = 1.35 + 0.56 Log Total Chlorophyll a . Lake area, shoreline length, and all trophic state parameters accounted for significant portions of the variance in total species richness. Multiple regression analyses indicated that l...

Submerged‐vegetation changes in Lake Rotoroa (Hamilton, New Zealand) related to herbicide treatment and invasion byEgeria densa

Abstract Lake Rotoroa is a small (54 ha), shallow (maximum depth 6 m), urban lake which has been subject to repeated chemical weed control since 1957. The distribution and abundance of aquatic macrophytes in the lake were studied in six SCUBA surveys between 1977 and 1986. During this period three applications of diquat herbicide resulted in periodic decreases in submerged vascular plant growths in the lake. Macrophytes were present over c. 80% of the lake bed to a maximum depth of 5–5.5 m during the period of study. Emergent macrophytes, particularly Baumea articulata, Iris pseudacorus, Eleocharis sphacelata, and Typha orientalis, and floating‐leaved Nymphaea, were recorded around c. 50% of the lakeshore. In 1977 the most abundant submerged vascular plants were Lagarosiphon major and Elodea canadensis which were both recorded at all sampling sites. Egeria densa, which was first recorded in the lake in 1977, spread at the expense of these species to become the dominant vascular plant in the lake by 1986. In May 1986 it was present on all sampling profiles (35) and occupied an estimated 35% of the lake's vegetation ‐whercas Lagarosiphon and Elodea occupied an estimated 6% and < 1%, of the vegetation respectively. Extensive beds of charophytes (Chara corallina, Nitella hooked, and N. pseudoflabellata) persisted in the lake during the period of study. In May 1986 charophytes occupied an estimated 52% of the vegetation, their abundance apparently enhanced by selective herbicidal control of vascular species.

Effects of hydropower development on aquatic macrophytes in norwegian rivers: Present state of knowledge and some case studies

AbstractA multitude of Norwegian rivers are managed for generating hydroelectric power (HEP). The hydrology of these hydrorivers changes in various ways which reflect the implemented HEP schemes. Increased winter flows and a concomitant lack of ice‐cover are features found downstream of power installations on many Norwegian hydrorivers.Our study objectives were (1) to assess the changes in aquatic macrophyte abundance subsequent to HEP development; and (2) to evaluate the environmental conditions under which nuisance growths of macrophytes are likely to occur. Towards these ends, Norwegian literature data were compiled and assessed. Some case studies are outlined showing the variety of situations under which prolific growths of macrophytes might result. Unfortunately, available data on macrophyte‐associated problems proved deficient in many respects. This occurred chiefly because most macrophyte studies are conducted either before, or after, an HEP scheme is completed. Evidently, no concerted efforts are made for assessing the likelihood of macrophyte‐dominated nuisance growth in the planning stage of a Norwegian HEP scheme.

Patterns in Biomass and Cover of Aquatic Macrophytes in Lakes: Test with Florida Lakes

Data from 69 Florida lakes were used to test 15 empirical models that were developed from a worldwide data base to describe the biomass and cover of aquatic macrophytes in lakes. Ten of the models failed to provide useful predictions in Florida because the models did not adequately reflect the limnological characteristics of Florida lakes. Submerged and emergent biomass in the Florida lakes was predicted by the models that estimated these parameters from the areal cover of submerged and emergent vegetation. Total macrophyte cover in Florida lakes could be predicted from a model based on lake size, annual irradiance at the surface, and the mean annual irradiance within the mean depth of the lake. Even the best models, however, overestimated submerged plant biomass and cover in highly colored (&gt;400 Pt–Co units) lakes and lakes with steep (slope &gt;15%) littorals. This suggests that the influence of light (quantity and quality) and littoral slope on the abundance of aquatic macrophytes needs additional research before improved empirical models can be developed for lakes located in limited geographic regions.

Influence of Nutrient Enrichment and Light Availability on the Abundance of Aquatic Macrophytes in Florida Streams

A survey of 17 Florida streams was conducted between October 1984 and August 1986 to determine if the abundance of aquatic macrophytes was related to nutrient enrichment. Macrophyte standing crops were not correlated with in-stream total phosphorus or total nitrogen concentrations. Aquatic macrophytes contained less than 2% of the annual nutrient discharge in nearly all streams. Nutrients are, therefore, not considered to be the primary factor regulating the abundance of aquatic macrophytes in most Florida streams. Shading by riparian vegetation seems to be the dominant factor controlling the location and abundance of aquatic macrophytes. Statistical analyses indicated that the potential average and maximum standing crop of aquatic macrophytes in the sampled streams could be estimated by the equations[Formula: see text]where SCavg and SCmax are the average and maximum standing crop of aquatic macrophytes (kilograms fresh weight per square metre), respectively, and %C is the percent canopy coverage by riparian vegetation.

Aquatic plants of acid lakes in Kejimkujik National Park, Nova Scotia; floristic composition and relation to water chemistry

To document the aquatic flora of acid lakes in Kejimkujik National Park, N.S., the presence and abundance of aquatic macrophytes growing in water deeper than 3 dm were recorded in 20 lakes. Of the 45 species found, the most important were Sphagnum macrophyllum, Eriocaulon septangulare, Utricularia purpurea, Scirpus subterminalis, Pontederia cordata, Nuphar variegatum, Nymphaea odorata, Eleocharis acicularis, Sparganium angustifolium, Potamogeton confervoides, Lobelia dortmanna, Potamogeton epihydrus, and Utricularia vulgaris. To explore the relationship between floristic composition and water chemistry, information on 12 chemical variables and colour was related to species presence–absence using a nonparametric test based on relative neighbourhood graphs. Analyses of variance (ANOVAs) using chemical data and six groups suggested by a conditional clustering of the species presence–absence data demonstrated significant heterogeneity in Ca, pH, and HCO3. Furthermore, these three proved to be highly correlated. A canonical variate analysis of the six groups revealed one significant axis and separated the lakes into two major groups, characterized by relative acidity. An ANOVA of these two groups established that colour was also significant. There were fewer species in the more acidic (range 8–20, average 15) than in the less acidic lakes (range 15–32, average 22).

Comparison of Species Composition and Richness of Fish Assemblages in Altered and Unaltered Littoral Habitats

ABSTRACT Species composition and richness of fish assemblages in altered and unaltered littoral habitats in Lake St. Clair, Michigan, differed between areas. A percid-cyprinid-cyprinodontid assemblage dominated in the unaltered area, Muscamoot Bay, which has a natural shoreline (with almost no alteration due to dredging or bulkheading), high water quality, and high species richness of aquatic macrophytes. A centrarchid assemblage dominated in the altered area, Belvidere Bay, which has a bulkheaded shoreline, many dredged areas, reduced water quality due to inputs of nutrients from a nearby river, and relatively low species richness of aquatic macrophytes. Habitat factors, species richness and abundance of aquatic macrophytes, had the most influence on fish community structure in both areas. The percid-cyprinid-cyprinodontid assemblage was significantly correlated with six species of macrophytes whereas the centrarchid assemblage was significantly correlated with only four. These patterns suggested that pr...

The Effects of a Small Reservoir on the Seasonality and Stability of Physicochemical Parameters and Macrobenthic Community Structure in a Rocky Mountain Stream

Physicochemical and biotic characteristics of a headwater stream community above an impoundment on the Sante Fe River, New Mexico, were compared to those in its tailwaters. There was less seasonality in abiotic factors, particularly in discharge and temperature below the impoundment. The streambed below the reservoir was more heterogenous and more stable than that above. Macroinvertebrate density was almost five times greater below the reservoir as a result of enhanced temperature and flow constancy, greater substrate stability and the abundance of aquatic macrophytes at this site. Species richness was also greater below the impoundment and was directly related to its habitat heterogeneity. Reduced discharge and more constant temperatures in conjunction with extremely high macroinvertebrate densities resulted in reduced diversity below the impoundment. Evenness was also reduced. An analysis of seasonal evenness variances and a study of the seasonal abundance patterns of individual taxa indicated that the more constant physicochemical conditions below the reservoir probably decreased biotic interactions and reduced the community stability at this site.

Life history and microdistribution of Neureclipsis bimaculata (Trichoptera: Polycentropodidae) in a lake outflow stream of Alberta, Canada

A population of Neureclipsis bimaculata was studied from November 1980 to September 1982. The life cycle was bivoltine during both years. Development was direct and the population overwintered as larvae. The summer generation took only 6 to 7 weeks to complete, while the winter generation took the remainder of the year. Adult emergence took place from late May to early September, with two distinct peaks corresponding to the two generations. In both years summer generation larvae and adults were much more numerous than the winter generation. Production of this population (both generations) was estimated at 3.43 g∙m−2∙year−1 (ash free dry mass). The type and abundance of aquatic macrophytes influenced larval microdistribution by acting as a substratum for the large capture nets of larvae. Potamogeton richardsonii and Equisetum were important substrata in summer. In winter, Chara was an important substratum, since it was the only major structural component on the mud-sand bottom during that season. Maintenance of capture nets was seasonal (May to September or early October) and appeared to be related to temperature. Cumulative degree-days were not sufficient to account for apparent differences in voltinism between populations; these differences may be a function of food supply, which in part is related to the productivity of the water body.