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Inventory and Initiation Zone Characterization of Debris Flows on Mount St. Helens, Washington Initiated during a Major Storm Event in November, 2006Olson, Keith Vinton 15 November 2012 (has links)
The heavy precipitation event of November 3-8, 2006 dropped over 60 cm of rain onto the bare southern slopes of Mount St. Helens and generated debris flows in eight of the sixteen drainages outside the 1980 debris avalanche zone. Debris flows occurred on the upper catchments of the Muddy River, Shoestring Glacier, Pine Creek, June Lake, Butte Camp Dome, Blue Lake, Sheep Creek, and South Fork Toutle River. Debris flows were clustered on the west and south-east sides of the mountain. Of the eight debris flows, three were initiated by landslides, while five were initiated by headward or channel erosion. Six debris flows were initiated in deposits mapped as Holocene volcaniclastic deposits, while two were in 1980 pyroclastics on andesite flows. The largest (~975,000 m2) and longest (~8,900 m) debris flow was initiated by landslides in the upper South Fork Toutle River Drainage. The average debris flow initiation zone elevation was 1,750 m, with clusters around 1,700 m and 2,000 m elevation. The lower cluster is associated with basins that host modern or historic glaciers, while the upper is possibly associated with recent pyroclastic deposits. Upper drainages with debris flows averaged 41% slopes steeper than 33 degrees, while those without debris flows averaged 34%. The upper basins with debris flows averaged 6% snow and ice cover, 21% consolidated bedrock, and 74% unconsolidated deposits. Basins without debris flows averaged 3% snow and ice cover, 27% bedrock, and 67% unconsolidated deposits. Drainages with debris flows averaged an 89% loss of glacier area between 1998 and 2009, while those without debris flows lost 68%. Further comparing glacier coverage during that period found that only five of ten glaciers still existed in 2009. On average, the glaciers had reduced in area by 67%, decreased in length by 36%, and retreated by an average of 471 m during that period. Basin attributes were measured or calculated in order to construct a predictive debris flow model based on that of Pirot (2010) using multiple logistic regression. The most significant factors were the percentage of slopes steeper than 33 degrees, unconsolidated deposits in the upper basin, and average annual rainfall. These factors predicted the 2006 debris flows with an accuracy of 94% in a debris flow susceptibility map for Mount St. Helens.
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Zooplankton Community Structure in Lakes Near Mt. St. Helens, WAScharnberg, Larry Duane 21 February 1995 (has links)
Eighteen lakes around Mt. St. Helens (MSH) were sampled for zooplankton from September '92 until September '94. Samples were enumerated and identified to the species level in most cases. Standard deviation and t-tests were performed to determine the precision of enumeration methods and replication of duplicate tows. Palatability indexes based upon predator preferences were developed and coupled with length-frequency analyses as indicators of predation pressure. The weighted means of the summer samples were then subjected to cluster analysis in an attempt to categorize lakes with respect to zooplankton community structure. Lastly, the community compositions and abundances of MSH lakes were compared to those in lakes on Mt. Rainier and Mt. Hood in an attempt to assess recovery of MSH lakes from the 1980 eruption. Results of analyses indicate the presence of three distinct groups of lakes: 1) A group of lakes with heavy predation resulting in simplified zooplankton communities dominated by Keratella, Ke/licottia, and sometimes cyclopoid species. Predation in these instances can be attributed to extremely high fish or Chaoborus abundance. 2) A second group of lakes characterized by great depth, high transparency, significant abundances of Diaptomus kenai, and moderate to light fish predation. These lakes support balanced zooplankton communities with substantial proportions of Daphnid and calanoid specimens attaining large size. Significant indications of size-specific niche differentiation among the cladocerans are notably absent from these first two groups. 3) A third group consists of lakes which appear to be more productive than the other two groups. This group has higher biovolumes of zooplankton in general, coexistence of several different sized cladoceran species, the highest diversity indices of all the lakes sampled, and moderate predation as indicated by length-frequency analysis. Two conclusions are drawn from the data. First, it appears that predation and primary productivity are both significant factors affecting the abundance and composition of MSH zooplankton communities. Additionally, these data document a significant overlap in zooplankton species in lakes near Mt. Rainier and Mt. Hood, suggesting that the zooplankton communities in lakes around MSH have recovered from the effects of the 1980 eruption.
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Age, growth and maturity of the longnose skate (Raja rhina) for the U.S. west coast and sensitivity to fishing impactsThompson, Josie E. 06 September 2005 (has links)
In the past, sharks, skates and ray species have mainly occurred in incidental
fisheries. Now they are increasingly being directly targeted due to the depleted status
of traditionally targeted species. The life history characteristics of many
elasmobranch species make them more sensitive to high rates of fishing mortality.
The combination of these factors has resulted in the known local depletion of several
elasmobranch species; including the barndoor skate, Raja laevis, of the Northwest
Atlantic and the common skate, Raja batis, of Irish Sea. The longnose skate, Raja
rhina, occurs commonly as incidental catch in trawl fisheries off the coast of
California, Oregon and Washington. Commercial landings of skates, including R.
rhina, have increased dramatically along the U.S. West coast. The objectives of this
study have been to calculate accurate growth and maturity parameters for Raja rhina
in order that the vulnerability of this species to fishing mortality can be assessed. The
slow growth rates (k=0.04 to 0.06) and late ages-at-50% maturity (11 to 16 years
with maximum ages between 15 and 22 years, depending on sex and region) which
were calculated indicate that this species may be at great risk of depletion in the
future. Survey biomass trends indicate that R. rhina populations have remained stable
over the past twenty years. However, the possibility that biomass levels in the distant
past were much higher than they are at present cannot be ruled out. It is
recommended that the collection of fishery-dependent data for this species and other
skate species begins immediately. This information, along with the results found in
this are needed for a proper assessment for Raja rhina, so that the effects of current
fishing pressures can be evaluated and regulated appropriately. / Graduation date: 2006
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Microbial community structure as influenced by season and stand age in a Douglas-fir (Pseudotsuga menziesii) ecosystemKucera, Jennifer Moore 01 June 2005 (has links)
Forest harvest can have significant impacts on forest ecosystems that may
influence the capacity of soils to sequester carbon (C). The microbial community
controls decomposition, which is a critical process in partitioning litter- and root-C
between CO₂ and storage in semi-permanent soil-C pools. The objectives of this study
were to determine the effect of clear-cutting and stand age on: 1) temporal dynamics
of soil microbial community (SMC) structure and physiological status; and 2) shifts
among microbial functional groups in taking up ¹³C-labeled plant materials during
decomposition. The experiment was conducted in Douglas-fir ecosystems within the
Gifford Pinchot National Forest, Washington. We chose stands of three different
ages: old-growth where trees are between 300 and 500 years old; an 8-year old stand;
and a 25-year old stand. Phospholipid fatty acid (PLFA) profiling and ¹³C-PLFA
labeling techniques along with the ratio of saturated to monounsaturated PLFAs and
the ratios of cyclopropyl PLFAs to their monoenoic precursors as microbial
physiological stress markers were utilized.
Microbial PLFA profiles showed that SMC structure and physiological status
was most affected by season and secondarily by time since clear-cutting. Total
microbial biomass and bacterial and fungal biomass were significantly reduced in CC8
but not in CC25 sites relative to old-growth sites. Total microbial biomass
concentration was lowest and the stress indicators were highest in August, which
corresponded to low soil moisture and high temperatures.
The relative amount of ¹³C incorporated into PLFAs was also influenced by
stand age and ¹³C source (¹³C-labeled litter vs. ¹³C-labeled root material). A
significantly greater amount of ¹³C was incorporated in CC8 samples compared to
OG1 samples in five out of the seven sample dates. Additionally, a significantly
greater proportion of ¹³C was incorporated into soil samples containing the ¹³C-labeled
litter material relative to samples containing ¹³C-labeled root material in four out of
the seven dates. In general, 18:lω9 and 18:2ω6,9 (common fungal biomarkers) had
the greatest amount of ¹³C incorporation throughout the study period in both clear-cut
and old-growth sites, indicating the important role of fungi in the decomposition of
litter and root material and translocation of C within soil layers. / Graduation date: 2006
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Relationships between oceanographic factors and the distribution of juvenile coho salmon (Oncorhynchus kisutch) off Oregon and Washington, 1982-1983Chung, Alton W. 01 March 1985 (has links)
Juvenile coho salmon (101-400 mm) were sampled by
purse seine off the Pacific Coast from Waatch Point,
Washington to Four Mile Creek, Oregon, out to 30 mi
offshore, during the months of May, June, and September in
1982 and 1983. Sea surface temperature, surface salinity,
surface chlorophyll-a concentration, and Secchi depth were
measured at each station. Sea surface temperatures were
higher in 1983 than in 1982, while surface chlorophyll-a
concentrations and surface salinities were lower. Catch
data were not highly correlated with any of the four
physical parameters measured.
Strong northerly winds and strong upwelling tended to
disperse juvenile coho offshore and south. Fish were found
closer inshore during periods of weak winds and weak
upwelling. In both years the center of distribution of the
fish appeared to shift northward as the summer progressed.
Larger fish, in general, were found farther north and
offshore throughout the year. / Graduation date: 1985
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Ecology of populations of Van Dyke's salamanders in the Cascade Range of Washington StateMcIntyre, Aimee P. 18 November 2003 (has links)
The Van Dyke's salamander (Plethodon vandyke,) is a rare species endemic to
Washington State. It has been found in cool moist microhabitats along streams, splash zones
of waterfalls, and headwater seeps. We explored the association of the Van Dyke's
salamander with hydrologic condition, geomorphology, disturbance characteristics, and
vegetation structure in first- and second-order streams, and headwater seeps in the Cascade
Range of Washington. We conducted salamander surveys and measured habitat
characteristics at 50 streams and 40 seeps May-October 2000-2002. We described Van
Dyke's salamander occurrence in stream and seep sites at three spatial scales: between
sites, within sites, and between microhabitat sites. Using presence and absence as the
response, we fit logistic regression models predicting Van Dyke's salamander occurrence. To
identify the model that best fit the data, we ranked a priori models using Bayesian Information
Criterion (BIC). Results were consistent for both stream and seep sites, at all three spatial
scales. Best approximating models indicated that Van Dyke's salamander occurrence at sites
was related to geological and hydrological habitat characteristics that provided hydnc and
thermal stability.
The probability of Van Dyke's salamander occurrence along streams was associated
with habitat characteristics that protected salamanders from exposure, provided a source
cover, and stream habitat types providing splash zone areas. Between streams, Van Dyke's
salamander occurrence was positively associated with the proportion of valley walls with
canopy cover <5%, the proportion of the stream channel dominated by bedrock, boulder, or
soil substrates, and additional stream channels entering the main channel. Within streams,
the probability of Van Dyke's salamander occurrence increased with the presence of non-forested
areas, the presence of bedrock dominated stream habitat types, and the presence of
vertical or V-shaped valley wall morphology. Between microhabitat sites, the probability of
Van Dyke's salamander occurrence increased with an absence of trees, the presence of
seeps, and the presence of small cobble sized substrates.
The probability of Van Dyke's salamander occurrence in seeps was associated with
habitat characteristics that protected salamanders within the larger landscape, provided a
moisture gradient from dry to saturated, and the presence of cover objects. Between seeps,
Van Dyke's salamander occurrence was positively associated with seep faces having a dry
and sheeting hydrology, and with seep faces >5 m high. Within seeps, the probability of Van
Dyke's salamander occurrence was negatively associated with seeps that had proportionately
more point measures of total overhead cover that were >25%. Between microhabitat sites,
the probability of Van Dyke's salamander occurrence was positively associated with an
increase in the percent cover of small cobble, small gravel, and bedrock substrates.
We conducted mark-recapture surveys of the Van Dyke's salamander at two high-gradient
stream sites located within the Cascade Range of Washington State, June-November
2002. Sites known to support populations of the Van Dyke's salamander were chosen, and
were ecologically different. One site, lacking significant overstory and located within the blast
zone created by the 1980 eruption of Mount St. Helens, was surveyed 10 times. The other
site, located in an old-growth coniferous stand, was surveyed 11 times. Abundance of
salamanders at the blast zone site was estimated to be 458 (95% Cl: 306-739). Abundance
of salamanders at the old-growth site was estimated to be 100 individuals (95% Cl: 61-209).
Capture probabilities were extremely low (5 = <0.10) for all trapping occasions at both sites,
with an average capture probability for the two sites of 0.038 (range = 0.02-0.09). Analysis of
movement patterns suggested that most individual salamanders had home ranges <2 m, at
least when moving on or near the surface. Individuals were recaptured under the same cover
object as initial capture 36% of the time, and 89% of the recaptured individuals moved <2 m.
Our results indicated that populations of the Van Dyke's salamander were rare on the
landscape, even within the species documented range. Van Dyke's salamander occurrence
was associated with geological and hydrological habitat characteristics that created
microhabitats favorable for a species that is especially sensitive to heat and drying due to
physiological constraints. Animals were difficult to detect due to fossorial habits and low
capture probabilities, and it is likely that the Van Dyke's salamander was not detected even at
sites where it existed. Life history characteristics, such as lunglessness and fossorial habits,
low capture probabilities, and low abundances make it difficult to manage for and protect the
Van Dyke's salamander. However, habitat associations may be used to identify and protect
habitats suitable for Van Dyke's salamander occurrence. / Graduation date: 2004
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The water and energy dynamics of an old-growth seasonal temperate rainforestLink, Timothy E. 02 October 2001 (has links)
In the Pacific Northwest (PNW), concern about the impacts of climate and land
cover change on water resources, flood-generating processes, and ecosystem dynamics
emphasize the need for a mechanistic understanding of the interactions between forest
canopies and hydrological processes. A detailed measurement and modeling program
during the 1999 and 2000 hydrologic years characterized hydrological conditions and
processes in a 500-600 year old Douglas fir-western hemlock seasonal temperate
rainforest. The measurement program included sub-canopy arrays of radiometers,
tipping bucket rain gauges, and soil temperature and moisture probes, to supplement a
vertical temperature and humidity profile within the forest canopy. Analysis of the
precipitation interception characteristics of the canopy indicated that the mean direct
throughfall proportion was 0.36, and the mean saturation storage was 3.3 mm.
Evaporation from small storms insufficient to saturate the canopy comprised 19% of
the net interception loss, and canopy drying and evaporation during rainfall accounted
for 47% and 33% of the net loss, respectively. Results of the measurement program
were used to modify the Simultaneous Heat and Water (SHAW) model for forested
systems. Changes to the model include improved representation of interception
dynamics, stomatal conductance, and within-canopy energy transfer processes. The
model effectively simulated canopy air and vapor density profiles, snowcover
processes, throughfall, soil water content profiles, shallow soil temperatures, and
transpiration fluxes for both a calibration period and for an uncalibrated year. Soil
warming at bare locations was delayed until most of the snowcover ablated due to the
large heat sink associated with the residual snow patches. During the summer,
simulated evapotranspiration decreased from a maximum monthly mean of 2.17 mm
day����� in July to 1.34 mm day����� in September, as a result of declining soil moisture and
net radiation. Our results indicate that a relatively simple parameterization of the
SHAW model for the vegetation canopy can accurately simulate seasonal hydrologic
fluxes in this environment. Application and validation of the model in other forest
systems will establish similarities and differences in the interactions of vegetation and
hydrology, and assess the sensitivity of other systems to natural and anthropogenic
perturbations. / Graduation date: 2002
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Habitat segregation of two ambystomatids in mountain ponds, Mount Rainier National ParkBrokes, Brendan J. 07 October 1999 (has links)
Ambystoma macrodactylum (long-toed salamander) and A. gracile (northwestern salamander) are two common salamander species occupying key trophic positions in mountain ponds of Mount Rainier National Park. The objective of this research was to document and evaluate the distributions and abundances of the two species, relative to habitat characteristics of ponds in the park.
Amphibian distributions and abundances were assessed in 20 ponds from June through September 1993 to 1996. Nutrient concentrations (total nitrogen, Kjeldahl-N, total phosphorus, and orthophosphate-P), habitat characteristics (surface area, depth, elevation, substratum organic content lost on ignition, amount of coarse woody debris, aquatic vegetation, and bottom firmness), and water quality (temperature, dissolved oxygen, alkalinity, conductivity, and pH) were measured.
Distinct habitat associations were found for each Ambystoma species. Ponds with one species only were different in surface area, maximum depth, substratum organic content, and elevation. Ponds with A. macrodactylum were small, shallow, high in elevation, and had firm sediments low in organic matter relative to A. gracile ponds. Ambystoma macrodactylum ponds typically contained little coarse woody debris relative to the amount of aquatic vegetation. Ambystoma gracile ponds were large, deep, low in
elevation, had flocculent sediment high in organic content, abundant coarse woody debris, and little aquatic vegetation relative to A. macrodactylum ponds. Two ponds supported reproducing populations of both species and exhibited habitat characteristics intermediate to the allopatric pond types. These findings suggest that habitat complexity plays an important role in the segregation of A. macrodactylum and A. gracile. / Graduation date: 2000
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Population structure of coastal cutthroat trout (Oncorhynchus clarki clarki) in the Muck Creek Basin, WashingtonZimmerman, Christian E. 23 October 1995 (has links)
The relationship of coastal cutthroat trout (Oncorhynchus clarki clarki) populations
in the Muck Creek basin, a 238 km�� southern Puget Sound stream basin in western
Washington, was examined using starch gel electrophoresis and meristic analysis. Coastal
cutthroat trout were collected from six sites throughout the basin including tributaries,
portions of the mainstem, and a lake. Four sites contained only resident trout, the lower
mainstem contained resident and anadromous trout, and the lake contained only mature
anadromous trout based on size and appearance. Patterns of allelic and meristic variation
suggest a significant structuring and separation of coastal cutthroat trout populations in the
basin. The lake population was distinguished from the other populations by significant
differences in allele frequencies and meristic characters. The other sites grouped more
closely together with significant variation among and between sites meristically and at
several loci. / Graduation date: 1996
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Origin of the Tucannon phase in Lower Snake River prehistoryLucas, Steven W. 29 September 1994 (has links)
Approximately 5,500 years ago a discreet period of
wetter and cooler environmental conditions prevailed
across the southern Columbia Plateau. This period was
marked by the first prominent episodes of erosion to occur
along the lower Snake River following the height of the
Altithermal and eruption of Mt. Mazama during the mid
post-glacial. In addition to the reactivation of small
stream courses choked with debris and sediment, large
stream channels began downcutting and scouring older
terrace faces incorporated with large accumulations of
Mazama ash. The resulting degradation of aquatic habitats
forced concurrent changes within human economies adapted
to the local riverine-environments. These adjustments
reported for the Tucannon phase time period along the
lower Snake River are notable and demonstrate the degree
to which Cascade phase culture was unsuccessful in coping
with environmental instability at the end of the
Altithermal time period. This successionary event has
demonstratively become the most significant post-glacial,
qualitative change to occur in the lifeways of lower Snake
River people prior to Euro-American influence. / Graduation date: 1995
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