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UBC Theses and Dissertations

Formica integroides of Swakum Mountain : a qualitative and quantitative assessment and narrative of Formica mounding behaviors influencing litter decomposition in a dry, interior Douglas-fir forest in British Columbia Pati, Adolpho J.


Formica spp. mound construction is fundamental to northern forests as their activities govern and shape forest floor dynamics and litter decomposition. The interior Douglas-fir forest at Swakum Mountain contains a super colony of Formica integroides whose presence and monolithic structures dramatically demonstrate their impact on the landscape. Through a series of observations, natural and controlled experiments I examine the effects of Formica mounding on litter decomposition. The basic measurements of temperature, moisture, evolved CO2, and mass loss reveal that Formica mounds buffer litter decomposition as Douglas-fir needles are carefully stacked, stockpiled, and assembled into thatch, where at the depth of ~ 8 cm thatch mass loss minimizes and begins to stabilize. The function of Formica mounding further exacerbates the prevailing arid conditions endemic to this forest type. Cotrufo's Microbial Efficiency-Matrix Stabilization (MEMS) framework sets forth a conceptual model where labile plant constituents are efficiently utilized by microbes and stabilized into soil organic matter (SOM). I integrate my findings within this framework while conceptualizing aspects of complexity theory as potential ecological drivers contributing to soil organic matter formation relating to Formica mounds. Through natural and controlled experiments my overall objective is to describe and explain litter decomposition involving Formica spp. within an interior Douglas-fir forest. I have included descriptive observations, sketches, and photographs involving the forest floor and Formica spp. behaviors and ecology to provide a holistic perspective describing litter decomposition within this local forest type. The framework of scientific methodology combined with a novel approach, provides further empirical and qualitative support for the findings of my research.

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Attribution-NonCommercial-NoDerivs 2.5 Canada