Biological Research

Posted On: Filed Under: Biological Research

Effects of elk and deer on early forest succession at Mount St. Helens

The objective of this study is to determine the role of elk and deer in the recovery of both natural and managed vegetation following volcanic disturbance. Additionally, we are interested in documenting the influence of elk and deer on vegetation establishment in areas that received different levels of volcanic impact. This goal will be achieved through a network of exclosures that will allow cross-site comparisons.

 

View the full abstract (57A)

Tags: , , , , ,

Posted On: Filed Under: Biological Research

Natural establishment of conifers at Mount St. Helens

This study tracks the establishment, survivorship, and growth rate of colonizing conifers on substrates deposited during the 1980 eruption of Mount St. Helens. Two 50 x 50 meter plots were installed at sites on the pyroclastic flow north of the crater and the upper portion of the Muddy River mudflow during 1989 and 1990. Two 50 x 50 meter plots were installed on the debris avalanche in 1993 and 1994. In each plot all individual trees are identified to species, measured (total height and stem diameter at ground level), and tagged.

 

View the full abstract (56A)

Tags: ,

Posted On: Filed Under: Biological Research

Mount St. Helens Data Network

After the eruption of Mount St. Helens, the National Weather Service placed a series of precipitation and river gauges around the mountain. This data network was put in operation to alert forecasters of heavy precipitation events and/or rapid rises on the Toutle and Cowlitz Rivers or rapid falls in lakes in proximity to the mountain. This paper explains that data network.

 

View the full abstract (55A)

Tags: ,

Posted On: Filed Under: Biological Research

Population dynamics and habitat ecology of elk in the Mount St. Helens blast zone

Population dynamics and seasonal patterns of foraging behavior of elk in the northwest portion of the Mount St. Helens blast zone were investigated during the years 1982 through 1985. A combination of rapid vegetation regrowth, mild winters, restricted human access and low harvests allowed a rapid re-invasion and recovery of the elk population.

 

View the full abstract (54A)

Tags: , , ,

Posted On: Filed Under: Biological Research

Seeding habits of upper-slope tree species

The Blue Lake noble fir plot is one of 52 plots established in the early and mid-1960’s throughout the Washington and Oregon Cascades to do a long-term study of the cone production of upper-slope conifers. Initially the objective was to characterize the size and frequency distribution of cone crops of important upper-slope tree species. Early results indicated that the pattern of cone production varies with geographic location, so a secondary objective to describe this variation was adopted. Another new objective is to describe how climate influences cone production. With the possibility of global warming this objective may become the most important.

 

View the full abstract (53A)

Tags:

Posted On: Filed Under: Biological Research

Soil nitrogen along a disturbance gradient.

Soils were studied along a disturbance gradient: Pumice Plain, Timberline parking lot, Harmony, Bismark Mtn., Elk Pass, and Fossil Creek Ridge. N03, NH4, N, P, K, Ca, Mg, C were assayed. NO3 and NH4 were also analyzed from resin bags buried at 15 and 30 cm. Soil samples were collected in 1985. Resin bags were buried for 1 year: 1985 – 86, and 1986 -87.

 

View the full abstract (52A)

Tags: , ,

Posted On: Filed Under: Biological Research

Summer bird populations of upper subalpine zone of Mount St. Helens, Mount Adams, and Mount Rainier.

Species composition and abundance of summer birds in the upper subalpine zone of Mount St. Helens were compared to those of Mount Adams and Mount Rainier in order to document these populations as well as to examine effects of the May 1980 eruption on bird populations at the volcano.

 

View the full abstract (51A)

Tags: , , , , ,

Posted On: Filed Under: Biological Research

Demography of Lupinus lepidus on the pumice plain and its role in primary and secondary succession.

This study details the demography of two populations of Lupinus lepidus, a primary successional plant species growing on the Pumice Plain, and also investigates the role lupine plays in the recruitment of additional species through facilitation. Lupine and other plant species’ populations have been censused once or twice each growing season from 1982-1991. Prairie lupine was the first species to colonize the barren deposits of the Pumice Plain and attained extremely high densities in certain portions of our plots during the census years.

 

View the full abstract (50A)

Tags: , ,

Posted On: Filed Under: Biological Research

Community reassembly following volcanic disturbance: the ground dwelling beetles (Coleoptera)

This study documents the recovery of beetles within the volcanically disturbed areas of Mount St. Helens and should provide an index to the rate and stage of ecosystem recovery at various points in time since the eruption. Beetles are ideal for monitoring ecological recovery following disturbance as they represent a broad trophic array. The ground dwelling beetle fauna of forests and clearcut habitats were sampled using pitfall traps (10 traps/site) that were open from the time of spring snow melt to early autumn from 1982-1984 and again in 1987 and 1990. Sites sampled include undisturbed “reference” areas and three post-eruption habitats (ashfall, blowdown, and pyroclastic/debris flow).

 

View the full abstract (49A)

Tags: , , , , , ,

Posted On: Filed Under: Biological Research

Reorganization of avian communities at Mount St. Helens

This study was initiated to document the reorganization of bird communities on lands disturbed by the cataclysmic eruption of Mount St Helens. Bird communities were surveyed along a disturbance gradient comprised of four structurally distinct volcanic impact zones and at undisturbed (reference) sites. Forty-two bird species were observed at the eight sites during the survey years. Species richness was inversely related to disturbance intensity. Richness values for the disturbance zones were; Reference (17), Ashfall (16), Blowdown (7) and Pyroclastic (2), respectively. Cluster analyses for community composition and foraging guilds indicate that our sites cluster into 3 groups: 1) sites that were volcanically undisturbed and those that received ashfall; 2) plots that experienced blowdown intensity force; 3) sites that were subjected to blast force intensity. The reorganization of bird communities is largely determined by the post eruptive habitat components available. As vegetation recovery increases across the landscape we expect to see recruitment of additional species and an eventual convergence of bird species composition among the sites.

 

View the full abstract (48A)

Tags: , ,