Biological Research

Posted On: Filed Under: Biological Research

Animal use of dead and down timber

Snags and blowdown trees that were killed by the May 1980 eruption were marked for future study. Objectives were to document animal use of snags and down timber and to observe changes in decay stage and wood nutrient status. Sound trees with bark and branches intact were originally marked in several areas of blowdown and standing dead zones.

 

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Spider biogeography at Mount St. Helens

Spider populations on the pumice plain were sampled and compared to those at a control site on the south slope of Mount St. Helens that received only tephra from the May 1980 eruption. All living organisms were either swept away or buried by the eruption at the pumice plain study site; there were no survivors and vegetation was sparse at this location during the years of sampling. Sampling at the control site revealed no significant effects on the spider community. The number of individuals trapped at both sites was nearly the same, but many more species were trapped on the pumice plain than at the control site. The majority of species arriving on the pumice plain are wind dispersed. They appear to be coming from lowlands approximately twenty miles to the west, transported by prevailing winds through the corridor of the Toutle River Valley. Most spiders perish soon after their arrival, and as of 1985, spiders were not colonizing this location.

 

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Mount St. Helens crater weather station

A weather station was established in the crater of Mount St. Helens to continuously monitor precipitation (both rain and snow), temperature, and water equivalence of snowpack. The information is gathered to provide baseline data for hydrologic hazards analyses.

 

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Observations on the floating log raft in Spirit Lake.

Observations on Spirit Lake and its log raft have been conducted since 1982. At that time a significant number (close to 20%) of the stumps (not the broken flotsam) had settled into an upright position in the water. This number included some that had floated into shallow water and had grounded lightly on the bottom (Coffin, 1983).

 

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Physiological and population ecology of two subalpine herbs on Mount St. Helens

This study examined the different adaptive strategies of two subalpine herbs in a stressful environment. The study site received tephra in the May 1980 eruption. Polygonum newberryi and Eriogonum pyrolifolium have markedly different morphological characteristics. The former is deciduous and has a large deep root system, the latter is wintergreen and has a shallow root system.

 

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Physiological and population ecology of lupines colonizing early successional habitats on Mount St. Helens

Lupinus lepidus and Lupinus latifolius were prominent survivors and among the first colonizers of early succession habitats following the 1980 eruption of Mount St. Helens. Several physiological and morphological properties of seedlings and adults were found to govern the response of these species to the harsh environmental conditions of these habitats.

 

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Climate/microclimate measurements over disturbed sites at Mount St. Helens

Climatic and microclimatic measurements for the summers of 1982 to 1987 were made at three differently disturbed sites around Mount St. Helens. These measurements provided daily information on the physical environment and baseline data for studying the evolution and recolonization of these areas.

 

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Recovery of net primary production in subalpine meadows of Mount St. Helens

Study sites that received tephra or mudflow deposits during the May 1980 eruption were examined and compared for effects on vegetation. Deposition of 5-10 cm of tephra resulted in less species diversity and inhibition of seedling establishment but did not significantly decrease net primary production (NPP); the NPP of these areas did fluctuate dramatically with precipitation rates during seven summers from 1980-1986.

 

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The evolutionary ecology of Lupinus lepidus

A four year study of the evolutionary consequences of colonization was begun in 1990. The objectives of this study are to document the pattern of genetic variation in a colonizing plant species, Lupinus lepidus, and investigate the ecological processes which are expected to affect that pattern.

 

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Recovery of aquatic insect communities in streams near Mount St. Helens

We have monitored stream insect communities from 1980 to 1988 in Clearwater Creek, Elk Creek, and Ape Canyon. Quantitative and qualitative samples indicate rapid colonization in 1981-82, and then a gradual increase in richness and diversity. Over 200 taxa have now been collected from Ape or Clearwater Creeks.

 

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