Effect of water depth on population parameters of a Typha glauca stand

1992 ◽  
Vol 70 (2) ◽  
pp. 349-351 ◽  
Author(s):  
I. Waters ◽  
J. M. Shay
Keyword(s):  
Water Depth ◽  
Shoot Density ◽  
Depth Range ◽  
Population Parameters ◽  
Shoot Height ◽  
Frequency Distributions ◽  
Shoot Size ◽  
Shoot Mass ◽  
Response To Water ◽  
Typha Glauca

The response of a Typha glauca stand to a water depth gradient was studied in a small marsh pond in Delta Marsh, Manitoba. Weekly density counts and height measurements were made from May to October 1986 in permanent quadrats at five depths from 25 to 100 cm. Shoot mass was estimated from shoot height using a regression model based on destructive analyses. Shoot density declined significantly from 41 shoots/m2 at 25 cm to 12 shoots/m2 at 85 cm but increased at 100 cm to 38 shoots/m2. Shoot mass increased in shoots growing at water depths from 25 to 65 cm, resulting in relatively constant stand biomass over this depth range. Stand biomass declined at 85 cm and reached its maximum (1789.8 g/m2) at 100 cm. Frequency distributions of shoot size categories based on height deviated from normality and were negatively skewed at all depths, with the greatest skewness occurring at 100 cm. These population parameters were interpreted as evidence of a plastic population response to water depth. Key words: clonal macrophyte, frequency distributions, plasticity, shoot density, Typha glauca, water depth.

Water-depth tolerances of the dominant emergent macrophytes of the Delta Marsh, Manitoba

1992 ◽  
Vol 70 (9) ◽  
pp. 1860-1867 ◽  
Author(s):  
Louisa Squires ◽  
A. G. Van der Valk
Keyword(s):  
Water Depth ◽  
Shoot Density ◽  
Shoot Length ◽  
Depth Gradient ◽  
Shoot Height ◽  
Delta Marsh ◽  
Below Ground ◽  
Seasonally Flooded ◽  
Water Depths

The growth (shoot height, cumulative shoot length, shoot density, above- and below-ground biomass) of seven emergent species growing at five different water depths was measured for 2 years. These species belonged to three different ecological classes: (i) upper marsh species (Carex atherodes, Scolochloa festucacea, and Phragmites australis) that occupy sections of the water-depth gradient that are only seasonally flooded in the Delta Marsh; (ii) lower marsh species (Typha glauca and Scirpus lacutris spp. glaucus) that occupy permanently flooded areas; and (iii) drawdown species (Scirpus lacustris spp. validus and Scirpus maritimus) that become established temporarily during drawdowns. Upper marsh species could not adjust their shoot length if they were growing in water deeper than 20 cm. Lower marsh species were able to do this in water up to 70 cm deep. All three types survived for 1 or 2 years in water too deep for long-term persistence. Scirpus species survived as tubers in areas with water too deep for them to grow. The distributions of the seven species in the experiments overlapped considerably, and all species cooccurred at water depths to 70 cm after 2 years of flooding. The predicted distribution in the four dominant species along a water-depth gradient were consistent with their actual distributions in the Delta Marsh, but their predicted distributions overlapped much more than is the case in the field. Key words: emergent vegetation, experiment, water-depth tolerance, plant growth, distributions.

scholarly journals In situ Responses of the Eelgrass Zostera marina L. to Water Depth and Light Availability in the Context of Increasing Coastal Water Turbidity: Implications for Conservation and Restoration

2020 ◽  
Vol 11 ◽  
Author(s):  
Shaochun Xu ◽  
Pengmei Wang ◽  
Feng Wang ◽  
Peng Liu ◽  
Bingjian Liu ◽  
...  
Keyword(s):  
Water Depth ◽  
Zostera Marina ◽  
Donor Site ◽  
Light Availability ◽  
Shoot Density ◽  
Depth Range ◽  
Light Deprivation ◽  
Depth Limit ◽  
Seagrass Meadows

Accelerating losses of seagrass meadows has led to efforts to restore these highly productive and beneficial ecosystems globally. Depth and light availability are critical determinants of seagrass restoration success. Eelgrass (Zostera marina L.) is the dominant seagrass species in the temperate northern hemisphere, but its global distribution has reduced dramatically. The main aims of this study were to determine: (1) the depth limit for Z. marina survival in Ailian Bay, north China, and (2) how light availability affects the growth and recruitment of Z. marina as a basis for identifying a suitable depth range for successful restoration. To achieve these aims, Z. marina shoots were transplanted from a nearby donor site, Swan Lake, to an experimental site, Ailian Bay, and the temporal responses of Z. marina shoots to light availability at water depths ranging from 1 to 8 m were investigated using in situ suspended cultures. Four suspended shoot transplantation experiments were conducted in 4 years. The results showed that the transplanted Z. marina shoots could survive and branch during an annual growth cycle, permanently underwater, at a depth ≤3 m. Due to the local turbidity of the waters in Ailian Bay, a depth of 4 m led to sufficient light deprivation (reduced to 6.48–10.08% of surface irradiance) to negatively affect seagrass shoot density and clonal reproduction. In addition, reproductive shoot density also tended to decline with water depth and light deprivation. Our results indicated that Z. marina population recruitment, through sexual and asexual (clonal growth) reproduction, were negatively affected by increasing water depth and light deprivation. These findings may provide a suitable depth range for the successful restoration of Z. marina in local coastal waters. They may also be applied to the management and restoration of Z. marina globally.

scholarly journals The effect of low initial medium pH on in vitro white poplar growth

2013 ◽  
pp. 67-80
Author(s):  
Branislav Kovacevic ◽  
Dragana Miladinovic ◽  
Marina Katanic ◽  
Zoran Tomovic ◽  
Sasa Pekec
Keyword(s):  
Biomass Accumulation ◽  
Dry Mass ◽  
White Poplar ◽  
Medium Ph ◽  
Shoot Height ◽  
Initial Ph ◽  
The Media ◽  
Initial Medium ◽  
Shoot Mass

The effect of low initial medium pH on shoot and root development of five white poplar (Populus alba L.) genotypes was tested. The shoot height, fresh mass of shoots per jar, dry mass of shoots per jar, number of roots, as well as the length of the longest root were measured and final pH of the media determined, after 35 days of culture in vitro. Three initial pH values of the medium were tested: 3.0, 4.0 and 5.5 as control. Agar solidification at pH 3.0 was not achieved after sterilization in autoclave, but it was successful after sterilizing in a microwave oven. The obtained results indicate that the tested genotypes are able to significantly influence the changes of media pH during culture. The effect of differences among the examined media was significant for biomass accumulation and final media pH. Generally, significantly higher values of fresh and dry shoot mass, shoot height and the longest root length were recorded on a medium with initial pH 3.0 then on a standard medium with pH 5.5.The implications of the obtained results for the improvement of in vitro propagation of white poplars are discussed.

Effects of nutrients and water levels on emergent macrophyte biomass in a prairie marsh

1990 ◽  
Vol 68 (5) ◽  
pp. 1007-1014 ◽  
Author(s):  
Christopher Neill
Keyword(s):  
Water Level ◽  
Nutrient Limitation ◽  
Water Depth ◽  
Nitrogen Limitation ◽  
Water Levels ◽  
Water Level Fluctuations ◽  
Depth Range ◽  
Dry Conditions ◽  
Second Year ◽  
Water Depths

Nitrogen and phosphorus fertilizers were added over two growing seasons to marshes dominated by whitetop grass (Scolochloa festucacea) or cattail (Typha glauca) in a prairie lacustrine marsh to assess nutrient limitation and the interaction of nutrient limitation with water depth. For each species, stands were selected at the deep and shallow extremes of its water depth range. Water levels were high during the first year of fertilization and low during the second year, exposing the fertilized stands to a variety of water depths. Nitrogen limited growth in whitetop and cattail marshes. Water level, by controlling whether the soil was flooded or the water table was below the soil surface, affected growth and the degree of nitrogen limitation. In whitetop marshes, nitrogen increased biomass more when the soil was flooded or when standing water was deeper and in cattail marshes, it increased biomass more under intermediate water depths (approximately 0–20 cm) than under more deeply flooded (20–40 cm) or dry conditions. Nitrogen reduced biomass in whitetop marshes the second year, apparently because growth was inhibited by fallen litter from the previous year. Nitrogen did not limit cattail marsh biomass in the driest locations during a year of low water levels. Phosphorus caused a small increase in growth of both species after 2 years. Changes of nitrogen limitation with flooding suggest that annual water level fluctuations, by creating alternating flooded and dry conditions, may influence the primary production of emergent macrophytes through effects on nitrogen cycling.

Ecological plasticity in Carex lyngbyei: evidence from transplant experiments

1989 ◽  
Vol 67 (12) ◽  
pp. 3618-3624 ◽  
Author(s):  
Susan R. Smythe ◽  
Ian Hutchinson
Keyword(s):  
Pacific Northwest ◽  
Shoot Density ◽  
Transplant Experiment ◽  
Reciprocal Transplant Experiment ◽  
Shoot Height ◽  
Reciprocal Transplants ◽  
Morphological Differences ◽  
Northwestern North America ◽  
Transplant Site ◽  
Transplant Experiments

Four populations of Carex lyngbyei from each of three estuaries with contrasting salinity regimes in northwestern North America (deltas of the Nanaimo, Skagit, and Squamish rivers) were grown in a reciprocal transplant experiment to determine the degree to which morphological differences were genetic or environmentally based. Shoot height, biomass per shoot, and aboveground biomass differences were generally not maintained in the transplant environment, suggesting that genetic control on morphological variation was weak. Transplant site salinity regimes had little effect on shoot density or survival. It is suggested that broadly adapted genotypes, capable of this sort of plastic response, may have a competitive advantage in these fluctuating estuarine environments. Key words: Carex lyngbyei, Pacific Northwest, plasticity, reciprocal transplants.

High Capacity Carousels: Modularity, Technical Development and Innovation

2014 ◽  
Author(s):  
David Tibbetts ◽  
Nicholas Dale
Keyword(s):  
Water Depth ◽  
High Capacity ◽  
Depth Range ◽  
Technical Challenge ◽  
Deep Waters ◽  
Offshore Installations ◽  
Recent Developments ◽  
Technical Innovations ◽  
The Impact ◽  
Flexible Products

Marine installation operations are becoming ever longer, larger and deeper. With campaigns regularly being carried out in the 2,000–3,000m water depth range and tieback lengths on the increase; installation, replacement or recovery works for this specification of product requires specialist equipment that can accommodate the increasing bulk of the flexible products being installed, without compromising the performance of the vessels which carry them. In order to fulfil this technical challenge, new and innovative carousel designs are being developed. Placing the ‘reel’ horizontally allows maximum product capacity whilst minimising the impact on the vessel, thus maintaining operational efficiency in both shallow and deep waters and for projects such as subsea tiebacks and connections to processing platforms and offshore installations. This paper explores recent developments in technology, where product loads of up to 1,500Te (Tonnes) are frequently required and ever shorter schedules are placed on contractors for initial spooling and subsequent installation. Technical innovations, operational solutions and commercial advantages will be assessed and the ability to open up new markets with the technology on offer will be scrutinised. Alongside this, the benefits of modularity are evaluated to quantify the advantages of being able to disassemble and transport this type of hardware worldwide and the vessel utilisation improvements that can be made.

scholarly journals Plant community characteristics and degradation mechanisms of the desert riparian zone in the lower reaches of the Ugan River, China

2021 ◽  
Author(s):  
TJ Z ◽  
yaning Chen ◽  
Jiazhen Liu ◽  
Yongjin Chen
Keyword(s):  
Distribution Pattern ◽  
Water Depth ◽  
Riparian Zone ◽  
Wiener Index ◽  
Field Investigation ◽  
Vegetation Coverage ◽  
Depth Range ◽  
Vegetation Degradation ◽  
Ecological Balance ◽  
Grey Correlation Analysis

The vegetation in the desert riparian zone represents a critical barrier in the maintenance of the ecosystem’s balance. However, in recent years, the vegetation degradation of the riparian zone have seriously hindered economic development and ecological environment conservation. Based on a field investigation and literature, the mechanisms of vegetation degradation in the lower reaches of the Ugan River are discussed in this study through the analysis of plant coverage, diversity, substitution rate, distribution pattern, grey correlation analysis, and the relationship with groundwater depth. The results showed that the vegetation coverage in this region is relatively low when the water depth exceeds 4 meters. Furthermore, the Shannon-Wiener index, the Simpson index and the Pielou index have all decreased with increases in water depth. Woody plants are the main species maintaining the ecological balance of the region with an aggregation distribution pattern. The degradation of vegetation is the result of the lack of water sources and intense water consumption caused by human activities(especially agricultural). To promote the ecological balance and vegetation restoration, the relative optimal water depth range can be maintained within 2 to 5 meters and proper control human activities.besides the degraded vegetation can gradually be restored using point and surface (i.e., flowering in the center and spreading to the surrounding areas).

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