LARCH SAWFLY SURVIVAL IN RELATION TO WATER LEVELS AND MICROTOPOGRAPHY IN TAMARACK BOGS

1968 ◽  
Vol 100 (4) ◽  
pp. 373-385
Author(s):  
W. G. H. Ives
Keyword(s):  
Small Area ◽  
Unit Area ◽  
Ground Surface ◽  
Water Levels ◽  
Tree Crowns ◽  
Pristiphora Erichsonii ◽  
Water Tables ◽  
Larch Sawfly ◽  
Two Factors ◽  
Excess Moisture

AbstractThe microtopography of a small area of tamarack bog was examined in detail and related to the distribution of cocoons of the larch sawfly Pristiphora erichsonii (Hartig). The relief of the ground surface under tree crowns was very similar to the surface not under crowns, although the whole profile was slightly higher. Cocoons were found down to the limnic peat, corresponding to the level of the lowest depressions, with the greatest numbers per unit area in the hummocks.The microtopographies in six tamarack bogs were sampled systematically and related to water levels, and an expression combining these two factors was related to larch sawfly survival. The microtopography in each bog did not change appreciably over a period of several years, but differences between bogs were pronounced and had a marked influence on the degree of flooding caused by equal changes in water tables. Excessive moisture during the period 1955–1966 was the prevalent condition in most of the bogs and extreme drought occurred only in 1961. There appeared to be a linear relationship between sawfly survival and an expression rating the favorableness of the cocoon environment in relation to excess moisture, but four divergent observations occurred among the data for 32 plot-years. It was postulated that these divergences were due to high mortality caused by a factor other than excess moisture.

Effects of Water Levels on the Overwintering Survival and Emergence of the Larch Sawfly in a Bog Habitat

1966 ◽  
Vol 98 (7) ◽  
pp. 768-777 ◽  
Author(s):  
W. G. H. Ives ◽  
L. D. Nairn
Keyword(s):  
Water Table ◽  
Adult Emergence ◽  
Water Levels ◽  
Pristiphora Erichsonii ◽  
Late Fall ◽  
Water Tables ◽  
Larch Sawfly ◽  
Maximum Water ◽  
Different Depths ◽  
Overwintering Survival

AbstractThe effects of fluctuating water tables on the survival of the larch sawfly, Pristiphora erichsonii (Hartig) (Hymenoptera: Tenthredinidae), were studied by burying cocoons at different depths in a tamarack bog. Most larvae in cocoons flooded during August or September died before winter. The percentage of overwintering survival of unflooded cocoons remained constant from late fall until development began in the spring. The higher the cocoons were above the maximum water table during August and September, the greater was the percentage of overwintering survival and subsequent adult emergence.

Pristiphora erichsonii. [Distribution map].

1959 ◽  
Author(s):  
Keyword(s):  
North America ◽  
Geographical Distribution ◽  
Distribution Map ◽  
Pristiphora Erichsonii ◽  
Larch Sawfly ◽  
New Distribution ◽  
Distribution In Europe

Abstract A new distribution map is provided for Pristiphora erichsonii (Htg.) (Hymenopt., Tenthredinoidea) (Larch Sawfly). Hosts: Larix spp. Information is given on the geographical distribution in EUROPE (excl. USSR), Austria, Britain, Czechoslovakia, Denmark, Finland, France, Germany, Ireland, Netherlands, Norway, Poland, Rumania, Sweden, ASIA (excl. USSR), Japan, USSR, NORTH AMERICA, Canada, U.S.A.

scholarly journals A partially-coupled hydro-mechanical analysis of the Bengal Aquifer System under hydrological loading

2018 ◽  
Author(s):  
Nicholas D. Woodman ◽  
William G. Burgess ◽  
Kazi Matin Ahmed ◽  
Anwar Zahid
Keyword(s):  
Mechanical Load ◽  
Groundwater Resources ◽  
Ground Surface ◽  
Coupled Model ◽  
Hydraulic Head ◽  
Water Levels ◽  
Elastic Model ◽  
Surface Boundary ◽  
Aquifer System ◽  
Terrestrial Water

Abstract. The coupled poro-mechanical behaviour of geologic-fluid systems is fundamental to numerous processes in structural geology, seismology and geotechnics but is frequently overlooked in hydrogeology. Substantial poro-mechanical influences on groundwater head have recently been highlighted in the Bengal Aquifer System, however, driven by terrestrial water loading across the Ganges-Brahmaputra-Meghna floodplains. Groundwater management in this strategically important fluvio-deltaic aquifer, the largest in south Asia, requires a coupled hydro-mechanical approach which acknowledges poro-elasticity. We present a simple partially-coupled, one-dimensional poro-elastic model of the Bengal Aquifer System, and explore the poro-mechanical responses of the aquifer to surface boundary conditions representing hydraulic head and mechanical load under three modes of terrestrial water variation. The characteristic responses, shown as amplitude and phase of hydraulic head in depth profile and of ground surface deflection, demonstrate (i) the limits to using water levels in piezometers to indicate groundwater recharge, as conventionally applied in groundwater resources management; (ii) the conditions under which piezometer water levels respond primarily to changes in the mass of terrestrial water storage, as applied in geological weighing lysimetry; (iii) the relationship of ground surface vertical deflection to changes in groundwater storage; and (iv) errors of attribution that could result from ignoring the poroelastic behaviour of the aquifer. These concepts are illustrated through application of the partially-coupled model to interpret multi-level piezometer data at two sites in southern Bangladesh. There is a need for further research into the coupled responses of the aquifer due to more complex forms of surface loading, particularly from rivers.

Estimation of Parasitism of Larch Sawfly Cocoons by Bessa harveyi Tnsd. in Survey Collections

1959 ◽  
Vol 91 (8) ◽  
pp. 496-500 ◽  
Author(s):  
W. G. H. Ives ◽  
R. M. Prentice
Keyword(s):  
Forest Insect ◽  
Small Areas ◽  
Pristiphora Erichsonii ◽  
Larch Sawfly ◽  
Insect Survey ◽  
Forest Biology ◽  
Biology Laboratory ◽  
Total Parasitism

The Forest Insect Survey at the Forest Biology Laboratory, Winnipeg, has been compiling records for a number of years on the percentage of cocoons of the larch sawfly, Pristiphora erichsonii (Htg.), parasitized by the tachinid Bessa harveyi Tnsd. Sawfly cocoons were collected each fall from the soil in infested stands, and those containing living larvae were dissected to determine the percentage of parasitism by B. harveyi. These estimates have been used to provide an index of parasitism (Lejeune and Hildahl, 1954), but are of limited value for a number of reasons: (1) estimates can be expressed only as percentage of sound cocoons parasitized; (2) total parasitism cannot be estimated because a portion of the parasites emerge from the cocoons before collection; and (3) estimates of parasitism may not be representative of the stand because there is a tendency to collect cocoons where they are easiest to find; hence all the cocoons in a collection may be from one or two small areas. If the proportion of cocoons containing B. harveyi varies within a stand such collections may give unreliable estimates of parasitism.

scholarly journals Evaluation of LNAPL Behavior in Water Table Inter-Fluctuate Zone under Groundwater Drawdown Condition

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2337
Author(s):  
Reza Azimi ◽  
Abdorreza Vaezihir ◽  
Robert Lenhard ◽  
S. Hassanizadeh
Keyword(s):  
Numerical Models ◽  
Water Levels ◽  
Injection Point ◽  
Monitoring Wells ◽  
Water Pumping ◽  
Two Factors ◽  
Injection Water ◽  
Phase Liquid ◽  
Flow Through ◽  
Material Grain Size

We investigate the movement of LNAPL (light non-aqueous phase liquid) into and out of monitoring wells in an immediate-scale experimental cell. Aquifer material grain size and LNAPL viscosity are two factors that are varied in three experiments involving lowering and rising water levels. There are six monitoring wells at varying distances from a LNAPL injection point and a water pumping well. We established steady water flow through the aquifer materials prior to LNAPL injection. Water pumping lowered the water levels in the aquifer materials. Terminating water pumping raised the water levels in the aquifer materials. Our focus was to record the LNAPL thickness in the monitoring wells under transient conditions. Throughout the experiments, we measured the elevations of the air-LNAPL and LNAPL-water interfaces in the monitoring wells to obtain the LNAPL thicknesses in the wells. We analyze the results and give plausible explanations. The data presented can be employed to test multiphase flow numerical models.

Hydrology of a Southern Appalachian Hypocrene Spring-Fed Fen

2020 ◽  
Vol 26 (3) ◽  
pp. 359-366
Author(s):  
Jeffrey Wilcox ◽  
Emily Bradshaw Marino ◽  
Adam Warwick ◽  
Megan Sutton
Keyword(s):  
Open Space ◽  
Ground Surface ◽  
Early Spring ◽  
Water Levels ◽  
Water Level Fluctuations ◽  
Fractured Bedrock ◽  
Southern Appalachian ◽  
Discharge Rates ◽  
Hydrologic Restoration ◽  
Spring Flow

ABSTRACT Garland Seep is a Southern Appalachian fen that supports a population of federally endangered green pitcher plants (Sarracenia oreophila). The wetland is underlain by clayey stream deposits above fractured bedrock, is located at the base of a mountain slope, and is fed by groundwater that originates as recharge on the adjacent hillslope. Groundwater wells were installed following a hydrologic restoration in the mid-1990s and have been monitored at varying frequencies since that time. The 20+ year record provides evidence that Garland Seep can be classified as a “hypocrene fen,” in which spring flow rarely reaches the ground surface because of low discharge rates and high evapotranspiration (ET). In general, water-level fluctuations followed seasonal ET patterns, with higher water levels in the winter and early spring (when ET is low) and lower levels in the summer and fall. During wetter years, the water table remained near the ground surface for much of the year, with the clay layer underlying the site retaining moisture even after water levels had dropped. The “clay wetting” period was shorter during dryer years and corresponded with a reduction in the number of pitcher plant clumps observed at the site. In addition to the geologic and climatic controls on hydrology, previous landowners used fire to maintain open space for grazing, and The Nature Conservancy has continued the practice to combat woody vegetation and to open the canopy. Prescribed burns reduce ET (at least initially), cause a rise in water levels, and have helped maintain a thriving Sarracenia population.

Mortality of Cocoons of the Larch Sawfly, Pristiphora erichsonii (Htg.), in Relation to Distance from Small-Mammal Tunnels

1959 ◽  
Vol 91 (9) ◽  
pp. 535-542 ◽  
Author(s):  
C. H. Buckner
Keyword(s):  
Small Mammals ◽  
Small Mammal ◽  
Natural Mortality ◽  
Mortality Factors ◽  
Forest Reserve ◽  
Pristiphora Erichsonii ◽  
Larch Sawfly ◽  
The Relationship

The relationship between the fate of cocoons of the larch sawfly, Pristiphora erichsonii (Htg.), and distance from small-mammal tunnels was studied during 1958 in the Whiteshell Forest Reserve of eastern Manitoba. The objects were to determine the distance that small mammals can detect cocoons and to observe possible effects of the interactions of small-mammal predation and other natural mortality factors of the insect. Additional analyses of the data provided information on the behaviour of the predators and the ecology of the prey insect.

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