Defining phreatophyte response to reduced water availability: preliminary investigations on the use of xylem cavitation vulnerability in Banksia woodland species

2006 ◽  
Vol 54 (2) ◽  
pp. 173 ◽  
Author(s):  
R. H. Froend ◽  
P. L. Drake
Keyword(s):  
Water Availability ◽  
Tree Mortality ◽  
Water Source ◽  
Resource Planning ◽  
Xylem Cavitation ◽  
Xylem Water Potential ◽  
Critical Thresholds ◽  
Species Response ◽  
Critical Range ◽  
Reduced Water

The consideration of phreatophyte response to changes in water availability is important in identifying ecological water requirements in water-resource planning. Although much is known about water-source partitioning and intra- and interspecific variability in groundwater use by Banksia woodland species, little is known about the response of these species to groundwater draw-down. This paper describes a preliminary study into the use of xylem cavitation vulnerability as a measure of species response to reduced water availability. A response function and critical range in percentage loss of conductance is identified for four Banksia woodland overstorey species. Similarity in the vulnerability curves of B. attenuata R.Br. and B. menziesii R.Br. at low tensions supports the notion that they occupy a similar ecohydrological niche, as defined by their broad distributions relative to depth to groundwater. B. ilicifolia R.Br., however, as an obligate phreatophyte, has a range restricted to environments of higher water availability and shallower depth to groundwater and this is reflected in greater vulnerability to cavitation (relative to other Banksia) at lower tensions. The wetland tree Melaleuca preissiana Schauer generally expressed a greater vulnerability at any given xylem water potential (Ψx). This paper identifies the range in Ψx within which there is an elevated risk of tree mortality, and represents a first step towards quantifying the critical thresholds in the response of Banksia woodland species to reduced water availability.

scholarly journals Prioritizing conservation actions in urbanizing landscapes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
A. K. Ettinger ◽  
E. R. Buhle ◽  
B. E. Feist ◽  
E. Howe ◽  
J. A. Spromberg ◽  
...  
Keyword(s):  
Coho Salmon ◽  
Predictive Accuracy ◽  
Critical Threshold ◽  
Negative Effects ◽  
Conservation Action ◽  
Critical Thresholds ◽  
Species Response ◽  
Response Data ◽  
Conservation Actions ◽  
Preservation And Restoration

AbstractUrbanization-driven landscape changes are harmful to many species. Negative effects can be mitigated through habitat preservation and restoration, but it is often difficult to prioritize these conservation actions. This is due, in part, to the scarcity of species response data, which limit the predictive accuracy of modeling to estimate critical thresholds for biological decline and recovery. To address these challenges, we quantify effort required for restoration, in combination with a clear conservation objective and associated metric (e.g., habitat for focal organisms). We develop and apply this framework to coho salmon (Oncorhynchus kisutch), a highly migratory and culturally iconic species in western North America that is particularly sensitive to urbanization. We examine how uncertainty in biological parameters may alter locations prioritized for conservation action and compare this to the effect of shifting to a different conservation metric (e.g., a different focal salmon species). Our approach prioritized suburban areas (those with intermediate urbanization effects) for preservation and restoration action to benefit coho. We found that prioritization was most sensitive to the selected metric, rather than the level of uncertainty or critical threshold values. Our analyses highlight the importance of identifying metrics that are well-aligned with intended outcomes.

RESPONSE OF LACTATING EWES TO SNOW AS A SOURCE OF WATER

1981 ◽  
Vol 61 (1) ◽  
pp. 73-79 ◽  
Author(s):  
A. A. DEGEN ◽  
B. A. YOUNG
Keyword(s):  
Weight Gain ◽  
Milk Yield ◽  
Total Body Water ◽  
Energy Content ◽  
Water Source ◽  
Feeding Period ◽  
Total Water ◽  
Water Turnover ◽  
Total Body ◽  
Reduced Water

Eight Suffolk-cross ewes, each nursing a ram-lamb, were kept in a snow-covered field and were individually offered 2 kg of dehydrated alfalfa pellets daily. Half the ewes were denied water from the 4th to 14th wk of lactation but had access to snow as a water source (snow ewes), while the others were offered water during the daily feeding period (water ewes). The ewes readily accepted snow as their source of water. The total water turnover of the snow ewes was approximately 35% less than that of the water ewes; however, this reduced water intake did not affect their milk yield, total body water, or hemactocrit. The liveweight and total body solids of the ewes and energy content of the milk were not significantly different in the two groups. The weight gain of the lambs from the two groups of ewes was not significantly different, averaging 118 and 105 g/day for lambs from the water and snow ewes, respectively.

scholarly journals The Hydraulic Modelling on Sediments Ponds in Binanga Aron River, North Sumatera Indonesia

2019 ◽  
Vol 8 (2) ◽  
pp. 392-404
Keyword(s):  
Water Flow ◽  
Water Availability ◽  
Soil Mechanics ◽  
Water Source ◽  
Water Sources ◽  
Hydraulic Modelling ◽  
Sediment Storage ◽  
Irrigation Area ◽  
Water Quality Status ◽  
Primary Channel

The development of dams and sediments ponds which is the hydrological planning to improve the aspect of irrigation, river engineering, foundations, soil mechanics, environmental engineering, hydrology and hydraulics. The management difficulty for a decision maker of environmental impacts which is the river's condition does not change for the better in direct response to reduction in nutrient concentration. The aims of this study to evaluate the design of reservoirs building and analysing the water flow and volume of sediment storage in the Binanga Aron River, Samosir, North Sumatera Indonesia. The hydraulic modelling on sediments ponds will ensuring the availability of sufficient volume of water, river flows and water quality status. The primary channel building is equipped with a door to prevent the rinsing water flow back to the primary channel and prevent the entry of rinsing water containing sediment into the canal. Then, the insufficient water availability from the river that is used as a water source in the irrigation area, then the irrigation area is still possible to supply water from nearby water sources. From the result, the volume of water recorded 1,977 ltr/s/ha with simultaneously delivery system. It is necessary to adjust the position of the dam, where the channel flow depth in the sedimentary bag building at least 0.236 m, the discharge ranges from 0.078 - 0.263 m3 /sec. The water availability planned of water sources into artificial reservoirs in the Binanga Aron River to maintain the water supply

Changes in arthropod community but not plant quality benefit a specialist herbivore on plant under reduced water availability

2020 ◽  
Author(s):  
Po-An Lin ◽  
Chia-Ming Liu ◽  
Jia-Ang Ou ◽  
Cheng-Han Sun ◽  
Wen-Po Chuang ◽  
...  
Keyword(s):  
Water Availability ◽  
Pieris Rapae ◽  
Plant Quality ◽  
Physiological Adaptation ◽  
Insect Herbivores ◽  
Specialist Herbivore ◽  
Herbivore Community ◽  
Two Populations ◽  
Reduced Water

AbstractPlants grow under reduced water availability can have divergent effects on insect herbivores, in some instances producing benefits to them. However, the forces mediating these positive impacts remain mostly unclear. We conducted a manipulative field study using a specialist herbivore Pieris rapae, and its host plant, Rorippa indica, in two populations to identify how water availability impacts overall plant quality and multitrophic interactions. We observed that R. indica growing under low water availability led to higher survival of P. rapae larvae. The increase in survival of eggs and larvae was related to the reduced abundance of other herbivores and natural enemies. Water availability had differential impacts on members of the herbivore community through changes in plant quality. Low water availability decreased the quality of R. indica to most herbivores as indicated by reduced abundance in the field and decreased relative growth rate in feeding assays. In contrast, the performance of P. rapae larvae were not affected by differences in sympatric R. indica grown under different water availability. These results indicate that local P. rapae possess some physiological adaptation to overcome fluctuations in host quality. Our findings illustrate that reduced water availability is beneficial to a specialist herbivore, but detrimental to most other herbivores. Our work highlights the complex roles of the arthropod communities associated with plants in determining the impacts of water availability on insect herbivores.

Crop Growth, Development and Yield in Semi-arid Conditions in Botswana. I. The Effects of Population Density and Row Spacing on Sorghum Bicolor

1986 ◽  
Vol 22 (2) ◽  
pp. 153-167 ◽  
Author(s):  
D. J. Rees
Keyword(s):  
Population Density ◽  
Water Availability ◽  
Dry Weight ◽  
Plant Size ◽  
Row Spacing ◽  
Grain Production ◽  
Crop Failure ◽  
Grain Yields ◽  
Critical Range ◽  
Dry Conditions

SUMMARYA series of population density and row spacing trials were carried out with sorghum in conditions of increasingly severe water stress from 1980 to 1984. In conditions of reasonable water availability, increasing density resulted in increased leaf area indices, dry weight production and grain yields. In conditions of severely limiting water availability, increasing density resulted in developmental delays, density-dependent mortality and reduced plant dry weights, with little increase in dry weight production per hectare. In these conditions grain yields were reduced by increasing density. The proportion of dry weight allocated to grain declined with increasing density and decreasing plant size, a consequence of the requirement for a minimum plant size to support grain production. When plant size was reduced below a critical range, disproportionately large reductions in grain yield resulted.Optimum densities for grain production varied from below 10 000 plants ha−1 in dry conditions to over 120 000 plants ha−1 in moist conditions. Medium density treatments produced the largest grain yields on a long term basis, but the low density treatment showed a reduced risk of crop failure and greater yield stability.

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