The recovery and dynamics of submerged aquatic macrophyte vegeta­tion in the Wilderness lakes, southern Cape

Bothalia ◽  
1992 ◽  
Vol 22 (2) ◽  
pp. 283-288 ◽  
Author(s):  
P. J. Weisser ◽  
A. K. Whitfield ◽  
C. M. Hall
Keyword(s):  
Species Composition ◽  
Seasonal Changes ◽  
Aquatic Macrophyte ◽  
Plant Biomass ◽  
Plant Populations

Between 1979 and 1981, the submerged aquatic macrophyte vegetation in the Wilderness lakes died back significantly, and in some areas disappeared altogether. This study documents the senescent phase and describes the recovery of the plant populations between May 1982 and May 1983. In two lakes, namely Langvlei and Eilandvlei, the plant biomass approximately doubled between the winters of 1982 and 1983. Seasonal changes in species composition are documented and possible factors accounting for the collapse and recovery of the plant populations are discussed.

Interactions between a planktivorous fish and planktonic microcrustaceans mediated by the biomass of aquatic macrophytes

2021 ◽  
Author(s):  
Bárbara Angélio Quirino ◽  
Franco Teixeira de Mello ◽  
Sabrina Deosti ◽  
Claudia Costa Bonecker ◽  
Ana Lúcia Paz Cardozo ◽  
...  
Keyword(s):  
Aquatic Macrophyte ◽  
Plant Biomass ◽  
Flow Speed ◽  
Trophic Niche ◽  
Planktivorous Fish ◽  
Low Flow ◽  
High Biomass ◽  
Predator Prey ◽  
Cladoceran Species ◽  
Macrophyte Biomass

Abstract Habitat complexity is recognized to mediate predator–prey relationships by offering refuge or not. We investigated the availability of planktonic microcrustaceans and the diet of a planktivorous fish (Hyphessobrycon eques) at different levels (low, intermediate and high) of aquatic macrophyte biomass. Sampling was carried out in a river with low flow speed, located in a Neotropical floodplain. We collected fish and microcrustaceans in macrophyte stands with variations in biomass. There were no differences in microcrustacean density in the water among the levels of macrophyte biomass, but microcrustacean richness and diet composition of H. eques differed. Microcrustacean richness and trophic niche breadth of the planktivorous fish were higher in high biomass stands. There was high consumption of a small cladoceran species in low macrophyte biomass, which was replaced by larger species, such as copepods, in intermediate and high biomass. Thus, the selection of some species was different among the biomass levels. These results suggest that plant biomass plays an important role in the interaction between fish and microcrustaceans, and prey characteristics such as size, escape ability and energy value make them more or less subject to predation by fish according to habitat structuring.

scholarly journals Seasonal changes in water quality and macrophytes and the impact of cattle on tropical floodplain waterholes

2012 ◽  
Vol 63 (9) ◽  
pp. 788 ◽  
Author(s):  
N. E. Pettit ◽  
T. D. Jardine ◽  
S. K. Hamilton ◽  
V. Sinnamon ◽  
D. Valdez ◽  
...  
Keyword(s):  
Water Quality ◽  
Seasonal Changes ◽  
Aquatic Macrophyte ◽  
Plant Cover ◽  
Critical Role ◽  
Dry Season ◽  
Nutrient Concentrations ◽  
Wet Season ◽  
Dry Tropics ◽  
The Impact

The present study indicates the critical role of hydrologic connectivity in floodplain waterholes in the wet–dry tropics of northern Australia. These waterbodies provide dry-season refugia for plants and animals, are a hotspot of productivity, and are a critical part in the subsistence economy of many remote Aboriginal communities. We examined seasonal changes in water quality and aquatic plant cover of floodplain waterholes, and related changes to variation of waterhole depth and visitation by livestock. The waterholes showed declining water quality through the dry season, which was exacerbated by more frequent cattle usage as conditions became progressively drier, which also increased turbidity and nutrient concentrations. Aquatic macrophyte biomass was highest in the early dry season, and declined as the dry season progressed. Remaining macrophytes were flushed out by the first wet-season flows, although they quickly re-establish later during the wet season. Waterholes of greater depth were more resistant to the effects of cattle disturbance, and seasonal flushing of the waterholes with wet-season flooding homogenised the water quality and increased plant cover of previously disparate waterholes. Therefore, maintaining high levels of connectivity between the river and its floodplain is vital for the persistence of these waterholes.

Seasonal changes of plant biomass at a constructed wetland in a livestock watershed area

2012 ◽  
Vol 45 (1-3) ◽  
pp. 136-143 ◽  
Author(s):  
Joan B. Gorme ◽  
Marla C. Maniquiz ◽  
Soyoung Lee ◽  
Lee-Hyung Kim
Keyword(s):  
Constructed Wetland ◽  
Seasonal Changes ◽  
Plant Biomass ◽  
Watershed Area

scholarly journals Effects of Plant Biomass, Plant Diversity, and Water Content on Bacterial Communities in Soil Lysimeters: Implications for the Determinants of Bacterial Diversity

2007 ◽  
Vol 73 (21) ◽  
pp. 6916-6929 ◽  
Author(s):  
Delita Zul ◽  
Sabine Denzel ◽  
Andrea Kotz ◽  
J�rg Overmann
Keyword(s):  
Species Composition ◽  
Water Content ◽  
Bacterial Diversity ◽  
Plant Species ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Plant Biomass ◽  
Bacterial Species ◽  
Bacterial Community Composition ◽  
Ecological Niches ◽  
Soil Lysimeters

ABSTRACT Soils may comprise tens of thousands to millions of bacterial species. It is still unclear whether this high level of diversity is governed by functional redundancy or by a multitude of ecological niches. In order to address this question, we analyzed the reproducibility of bacterial community composition after different experimental manipulations. Soil lysimeters were planted with four different types of plant communities, and the water content was adjusted. Group-specific phylogenetic fingerprinting by PCR-denaturing gradient gel electrophoresis revealed clear differences in the composition of Alphaproteobacteria, Betaproteobacteria, Bacteroidetes, Chloroflexi, Planctomycetes, and Verrucomicrobia populations in soils without plants compared to that of populations in planted soils, whereas no influence of plant species composition on bacterial diversity could be discerned. These results indicate that the presence of higher plant species affects the species composition of bacterial groups in a reproducible manner and even outside of the rhizosphere. In contrast, the environmental factors tested did not affect the composition of Acidobacteria, Actinobacteria, Archaea, and Firmicutes populations. One-third (52 out of 160) of the sequence types were found to be specifically and reproducibly associated with the absence or presence of plants. Unexpectedly, this was also true for numerous minor constituents of the soil bacterial assemblage. Subsequently, one of the low-abundance phylotypes (beta10) was selected for studying the interdependence under particular experimental conditions and the underlying causes in more detail. This so-far-uncultured phylotype of the Betaproteobacteria species represented up to 0.18% of all bacterial cells in planted lysimeters compared to 0.017% in unplanted systems. A cultured representative of this phylotype exhibited high physiological flexibility and was capable of utilizing major constituents of root exudates. Our results suggest that the bacterial species composition in soil is determined to a significant extent by abiotic and biotic factors, rather than by mere chance, thereby reflecting a multitude of distinct ecological niches.

Species composition and seasonal changes in macroalgal blooms in lagoons along the southeastern Gulf of California

2008 ◽  
Vol 51 (2) ◽  
Author(s):  
Alejandra Piñón-Gimate ◽  
Elisa Serviere-Zaragoza ◽  
María Julia Ochoa-Izaguirre ◽  
Federico Páez-Osuna
Keyword(s):  
Species Composition ◽  
Seasonal Changes ◽  
Gulf Of California ◽  
Macroalgal Blooms

The role of environmental variables on interannual variation in species composition and biomass in a subtropical minerotrophic floating marsh

1995 ◽  
Vol 73 (3) ◽  
pp. 413-424 ◽  
Author(s):  
Charles E. Sasser ◽  
Jenneke M. Visser ◽  
D. Elaine Evers ◽  
James G. Gosselink
Keyword(s):  
Species Composition ◽  
Environmental Variables ◽  
Plant Biomass ◽  
Dry Weight ◽  
Individual Species ◽  
Panicum Hemitomon ◽  
Dominant Plant Species ◽  
Related Plant ◽  
Floating Marsh

Floating marshes supporting emergent vascular vegetation occur in expansive areas in many parts of the world. We analyzed the long-term variability in species composition and related plant biomass to environmental variables in a subtropical minerotrophic floating marsh, Louisiana, U.S.A. Panicum hemitomon was the dominant plant species, representing 76% of the total mean end of season aboveground dry weight of 840 g∙m−2. Multivariate analyses showed that community structure in the Lake Boeuf floating marsh has changed little during the 11 years included in this study. Individual species occurring in varying frequency with the dominant, Panicum hemitomon, form two marginally distinct assemblages. Mean live end of season biomass varied from a low of 602 g dry wt∙m−2 to a high of 1173 g dry wt∙m−2 during the period of the study. Ninety-nine percent of the variation in total aboveground biomass can be predicted by environmental variables related to temperature, precipitation, evaporation, and water level. Mapping of the area for the years 1945, 1952, 1981, and 1992 show that a net loss of about 4% of marsh has occurred between 1945 and 1992. Key words: vegetation, stability, freshwater floating marsh, Panicum hemitomon, Louisiana, climate.

Sign in / Sign up

Export Citation Format

Share Document