Environmental factors and aquatic macrophyte response in regulated lakes - a statistical approach

1984 ◽  
Vol 19 (3-4) ◽  
pp. 199-220 ◽  
Author(s):  
Bjørn Rørslett
2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Zhigang Wu ◽  
Xinwei Xu ◽  
Juan Zhang ◽  
Gerhard Wiegleb ◽  
Hongwei Hou

Abstract Background Due to the environmental heterogeneity along elevation gradients, alpine ecosystems are ideal study objects for investigating how ecological variables shape the genetic patterns of natural species. The highest region in the world, the Qinghai-Tibetan Plateau, is a hotspot for the studies of evolutionary processes in plants. Many large rivers spring from the plateau, providing abundant habitats for aquatic and amphibious organisms. In the present study, we examined the genetic diversity of 13 Ranunculus subrigidus populations distributed throughout the plateau in order to elucidate the relative contribution of geographic distance and environmental dissimilarity to the spatial genetic pattern. Results A relatively low level of genetic diversity within populations was found. No spatial genetic structure was suggested by the analyses of molecular variance, Bayesian clustering analysis and Mantel tests. Partial Mantel tests and multiple matrix regression analysis showed a significant influence of the environment on the genetic divergence of the species. Both climatic and water quality variables contribute to the habitat heterogeneity of R. subrigidus populations. Conclusions Our results suggest that historical processes involving long-distance dispersal and local adaptation may account for the genetic patterns of R. subrigidus and current environmental factors play an important role in the genetic differentiation and local adaptation of aquatic plants in alpine landscapes.


2017 ◽  
Vol 69 (3) ◽  
pp. 427-437 ◽  
Author(s):  
Dragana Vukov ◽  
Milos Ilic ◽  
Mirjana Cuk ◽  
Ruzica Igic ◽  
Georg Janauer

Our objectives were to offer insight into the characteristics of the physical environment in the River Danube in Serbia; and to show the relationship between selected environmental factors and the composition and abundance of macrophyte species. The macrophyte survey method followed the European Standard EN 14184, applying Kohler?s five-level descriptive scale. Principal component analysis was carried out to examine the variation in aquatic vegetation, and to analyze the effect of environmental variables on the aquatic vegetation, redundancy analysis was used. To build a simpler model with fewer explanatory variables, yet sufficiently explaining species variability, forward selection of environmental variables was done. Our results confirmed that physical environmental factors significantly influence the establishment and structure of macrophyte vegetation, with the level of hydrological connectivity to the main river channel being the most important, followed by the transparency of the water column, sediment texture and water-flow velocity. In order to inspect the individual relation between best-fitted plant species and each of selected environmental variables, Spearman?s rank correlation coefficients were calculated. We have distinguished plant species with preferences to specific combinations of analyzed factors. Our results provide a background for future, more specific studies on the macrophyte/habitat relationship.


1991 ◽  
Vol 69 (7) ◽  
pp. 1542-1551 ◽  
Author(s):  
Douglas A. Wilcox ◽  
James E. Meeker

The effects of water-level regulation on aquatic macrophyte communities were investigated by comparing two regulated lakes in northern Minnesota with a nearby unregulated lake. Natural annual fluctuations of about 1.8 m were replaced with fluctuations of 1.1 m and 2.7 m in the regulated lakes, and the timing of water-level changes was also altered. Quadrats were sampled along transects that followed depth contours representing different plant habitats in the unregulated lake. Ordinations showed that the macrophyte communities at all sampled depths of the regulated lakes differed from those in the unregulated lake. The unregulated lake supported structurally diverse plant communities at all depths. In the lake with reduced fluctuations, only four taxa were present along transects that were never dewatered; all were erect aquatics that extended through the entire water column. In the lake with increased fluctuations, rosette and mat-forming species dominated transects where drawdown occurred in early winter and disturbance resulted from ice formation in the sediments. The natural hydrologic regime at the unregulated lake resulted in intermediate disturbance and high diversity. There was either too little or too much disturbance from water-level fluctuations in the regulated lakes, both resulting in reduced structural diversity. Key words: reservoirs, lake-level regulation, winter drawdown, aquatic vegetation, growth form, disturbance.


Plant Omics ◽  
2020 ◽  
pp. 30-36
Author(s):  
Natalja Škute ◽  
Marina Savicka ◽  
Aleksandrs Petjukevičs ◽  
Nadežda Harlamova

The epigenetic changes in the genome of plants are one of the important regulatory mechanisms in response to the environmental factors. The LUminometric Methylation Assay (LUMA) requires a relatively small DNA amount, a short processing time and is easily adapted for species with a non-resolved genome. The LUMA has not been previously used for ecological research of plants. In this research, LUMA was used for the first time to investigate the changes of global DNA methylation under different environmental factors in the leaves of different plants. The influence of salinity on global DNA methylation was studied on aquatic macrophyte Elodea canadensis Michx, which grew in aquatic tanks under different NaCl concentrations. After the third week of growth, the HpaII/MspI ratio was measured by LUMA and global DNA methylation percentages were calculated. The results showed salt stress-induced changes in the global DNA methylation level in E.canadensis leaves, compared to control. The response was salt dose-dependent. The changes of global DNA methylation in wildlife plant populations were analogically assessed on fen orchid Liparis loeselii (L.) Rich. It was shown that global DNA methylation level was higher in leaves of these plants in Engure Lake, where there are temporary changes in water regime, compared to leaves of plants from other places. It was assumed that global GC-DNA methylation plays an essential role in the survival of this plant. Therefore, we show the possibilities of using the LUMA method for epigenetic study of different plants ecological researches.


2011 ◽  
Vol 68 (10) ◽  
pp. 1778-1789 ◽  
Author(s):  
Alison Mikulyuk ◽  
Sapna Sharma ◽  
Scott Van Egeren ◽  
Eric Erdmann ◽  
Michelle E. Nault ◽  
...  

Quantifying the relative role of environmental and spatial factors to understand patterns in community composition is a fundamental goal of community ecology. We applied a tested and repeatable point-intercept sampling method to aquatic macrophyte assemblages in 225 Wisconsin lakes to understand the ability of environmental, land-use, and spatial patterns to explain aquatic plant distribution and abundance. Using a variation partitioning framework in conjunction with Moran eigenvector maps we found that environmental, land-use, and spatial patterns explained 31% of total adjusted variation in aquatic macrophyte assemblages across the landscape. Environmental factors were the most important (contributing 34% of the total explained variation), but all sources of variation were statistically significant. Community composition varied from north to south along a gradient of alkalinity and from disturbed to undisturbed lakes, diverging according to whether disturbance was urban or agricultural. The large amount of shared variation among predictor variables suggests causal relationships are complex and emphasizes the importance of considering space and land-use in addition to environmental factors when characterizing macrophyte assemblages. This work is the first to examine the joint and unique effects of environment, land-use, and spatial patterns on aquatic plant communities.


2019 ◽  
Vol 42 ◽  
Author(s):  
Nicole M. Baran

AbstractReductionist thinking in neuroscience is manifest in the widespread use of animal models of neuropsychiatric disorders. Broader investigations of diverse behaviors in non-model organisms and longer-term study of the mechanisms of plasticity will yield fundamental insights into the neurobiological, developmental, genetic, and environmental factors contributing to the “massively multifactorial system networks” which go awry in mental disorders.


2020 ◽  
Vol 134 (18) ◽  
pp. 2447-2451
Author(s):  
Anissa Viveiros ◽  
Gavin Y. Oudit

Abstract The global prevalence of obesity has been rising at an alarming rate, accompanied by an increase in both childhood and maternal obesity. The concept of metabolic programming is highly topical, and in this context, describes a predisposition of offspring of obese mothers to the development of obesity independent of environmental factors. Research published in this issue of Clinical Science conducted by Litzenburger and colleagues (Clin. Sci. (Lond.) (2020) 134, 921–939) have identified sex-dependent differences in metabolic programming and identify putative signaling pathways involved in the differential phenotype of adipose tissue between males and females. Delineating the distinction between metabolically healthy and unhealthy obesity is a topic of emerging interest, and the precise nature of adipocytes are key to pathogenesis, independent of adipose tissue volume.


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