Research About arthropods

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Cave biology in the Mount St. Helens Cave Basalt lava flow

This study seeks to establish an inventory of species inhabiting and using lava tubes and caves in the Cave Basalt lava flow. Bat populations in caves are dominated by Plecotus townsendii. Of small mammal species inhabiting or using caves, deer mice (Peromyscus maniculatus) are most wide spread. Few amphibians were observed; the most significant amphibian finding was a population of Larch Mountain salamander (Plethodon larselli). 256 invertebrate species of which approximately 100 species are arthropods have been collected in caves.

 

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Effects of May 1980 eruption on soil arthropods — a preliminary look

This preliminary investigation sampled soils in the blast area and blowdown zone in September 1980 for soil arthropods. Predictably, where disruption of pre-eruption ecosystems was most thorough — debris avalanche, pyroclastic flow, blast zone — no soil arthropods survived. In the blowdown zone, by contrast, soil arthropod populations were unaffected largely because they were protected by snow cover at the time of the eruption.

 

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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).

 

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Population ecology of the aphid Aphthargelia symphoricarpi on Mount St. Helens

I have examined the ecology of the aphid Aphthargelia symphoricarpi in terms of its interactions with its host plant Polygonum newberryi and its major predator, the ant Formica fusca. My approach involves a combination of field experimentation and observation with mathematical modelling.

 

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Arthropod recolonization of Mount St. Helens.

Ashfall and blast zone sites have been sampled in order to monitor the recovery of insect and spider populations reduced by the May 1980 eruption. There were many survivors of the eruption in ashfall sites, especially of sedentary species and others that were protected in micro-refugia. Mortality in arthropod populations was correlated with the depth of the ashfall. Using ant colonies as an index, areas with 15 cm or less of ash deposited had species numbers similar to sites outside the devastated area. However in all areas arthropod populations have remained low compared to arthropod population recovery following clearcutting.

 

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