scholarly journals Response of macroinvertebrate communities to temporal dynamics of pesticide mixtures: A case study from the Sacramento River watershed, California

2016 ◽  
Vol 219 ◽  
pp. 89-98 ◽  
Author(s):  
Ming-Chih Chiu ◽  
Lisa Hunt ◽  
Vincent H. Resh
Keyword(s):  
Temporal Dynamics ◽  
Sacramento River ◽  
Macroinvertebrate Communities ◽  
River Watershed ◽  
Pesticide Mixtures

Temporal dynamics of encrusting communities during the Late Devonian: a case study from the Central Devonian Field, Russia

Paleobiology ◽  
2017 ◽  
Vol 43 (4) ◽  
pp. 550-568 ◽  
Author(s):  
Michał Zatoń ◽  
Tomasz Borszcz ◽  
Michał Rakociński
Keyword(s):  
Temporal Dynamics ◽  
Small Sample ◽  
Time Interval ◽  
Faunal Turnover ◽  
Central Devonian Field ◽  
Before And After ◽  
Substrate Size ◽  
Mass Extinction Event ◽  
Diversity Dynamics

AbstractIn this study we focused on the dynamics of encrusting assemblages preserved on brachiopod hosts collected from upper Frasnian and lower Famennian deposits of the Central Devonian Field, Russia. Because the encrusted brachiopods come from deposits bracketing the Frasnian/Famennian (F/F) boundary, the results also shed some light on ecological differences in encrusting communities before and after the Frasnian–Famennian (F-F) event. To explore the diversity dynamics of encrusting assemblages, we analyzed more than 1300 brachiopod valves (substrates) from two localities. Taxon accumulation plots and shareholder quorum subsampling (SQS) routines indicated that a reasonably small sample of brachiopod host valves (n=50) is sufficient to capture the majority of the encrusting genera recorded at a given site. The richness of encrusters per substrate declined simultaneously with the number of encrusting taxa in the lower Famennian, accompanied by a decrease in epibiont abundance, with a comparable decrease in mean encrustation intensity (percentage of bioclasts encrusted by one or more epibionts). Epibiont abundance and occupancy roughly mirror each other. Strikingly, few ecological characteristics are correlated with substrate size, possibly reflecting random settlement of larvae. Evenness, which is negatively correlated with substrate size, shows greater within-stage variability among samples than between Frasnian and Famennian intervals and may indicate the instability of early Famennian biocenoses following the faunal turnover. The occurrence distribution of encrusters points to nonrandom associations and exclusions among several encrusting taxa. However, abundance and occupancy of microconchids remained relatively stable throughout the sampled time interval. The notable decline in abundance (~60%) and relatively minor decline in diversity (~30%) suggest jointly that encrusting communities experienced ecological collapse rather than a major mass extinction event. The differences between the upper Frasnian and lower Famennian encrusting assemblages may thus record a turnover associated with the F-F event.

Susceptibility Assessments and Validations of Debris-Flow Events in Meizoseismal Areas: Case Study in China’s Longxi River Watershed

2020 ◽  
Vol 21 (1) ◽  
pp. 05019005 ◽  
Author(s):  
Saier Wu ◽  
Jian Chen ◽  
Chong Xu ◽  
Wendy Zhou ◽  
Leihua Yao ◽  
...  
Keyword(s):  
Debris Flow ◽  
River Watershed

scholarly journals A Case Study in Watershed-Based Plan Development and Implementation for the May River Watershed in Bluffton, South Carolina

2014 ◽  
pp. 19-25
Author(s):  
Kimberly W. Jones ◽  
Ronald Bullman
Keyword(s):  
South Carolina ◽  
Environmental Control ◽  
Action Plan ◽  
River Watershed ◽  
Department Of Health ◽  
Close Proximity ◽  
Local Residents ◽  
Beaufort County ◽  
The Town

The Town of Bluffton, South Carolina was a one square mile coastal village until it experienced exponential growth in the early 2000s, and today is approximately 54 square miles. Until this recent growth, few sources of possible impairments to water quality were recognized within the watershed, and even fewer within close proximity to the river itself. In 2007, the Town was told by the S.C. Department of Health and Environmental Control (SCDHEC) that fecal coliform levels in the May River headwaters were increasing and in 2009 the river received a shellfish harvesting classification down-grade. In response to this down-grade, the Town of Bluffton, with Beaufort County and stakeholders, committed to take action to restore shellfish harvesting in the river and to prevent further degradation to the river. Following the U.S. EPA (EPA) guidelines for developing watershed plans, Town staff worked for nearly a year with consultants, Beaufort County, topic experts and local residents to develop the May River Watershed Action Plan which was adopted by Town Council in November 2011.

scholarly journals Spatial and Temporal Variations of Nitrogen and Phosphorus in Surface Water and Groundwater of Mudong River Watershed in Huixian Karst Wetland, Southwest China

2021 ◽  
Vol 13 (19) ◽  
pp. 10740
Author(s):  
Linyan Pan ◽  
Junfeng Dai ◽  
Zhiqiang Wu ◽  
Liangliang Huang ◽  
Zupeng Wan ◽  
...  
Keyword(s):  
Surface Water ◽  
Temporal Dynamics ◽  
Flow Direction ◽  
Influencing Factor ◽  
Shallow Groundwater ◽  
Temporal Variations ◽  
Field Investigation ◽  
Spatial And Temporal Variation ◽  
Nitrogen And Phosphorus ◽  
River Watershed

When considering the factors affecting the spatial and temporal variation of nitrogen and phosphorus in karst watersheds, the unique karst hydrogeology as an internal influencing factor cannot be ignored, as well as natural factors such as meteorological hydrology and external factors such as human activities. A watershed-scale field investigation was completed to statistically analyze spatial and temporal dynamics of nitrogen and phosphorus through the regular monitoring and collection of surface water and shallow groundwater in the agricultural-dominated Mudong River watershed in the Huixian Karst Wetland over one year (May 2020 to April 2021). Our research found that non-point source pollution of nitrogen (84.5% of 239 samples TN > 1.0 mg/L) was more serious than phosphorus (7.5% of 239 samples TP > 0.2 mg/L) in the study area, and shallow groundwater nitrogen pollution (98.3% of 118 samples TN > 1.0 mg/L) was more serious than surface water (68.6% of 121 samples TN > 1.0 mg/L). In the three regions with different hydrodynamic features, the TN concentration was higher and dominated by NO3−-N in the river in the northern recharge area, while the concentrations of TN and TP were the highest in shallow groundwater wells in the central wetland core area and increased along the surface water flow direction in the western discharge area. This research will help improve the knowledge about the influence of karst hydrodynamic features on the spatial patterns of nitrogen and phosphorus in water, paying attention to the quality protection and security of water in karst areas with a fragile water ecological environment.

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