An analysis of the influence of thermal heterogeneity within mountain environments on the spatial distribution and thermal biological characteristics of surface-dwelling arthropods

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Hassink, Nicholas J.
University of Lethbridge. Faculty of Arts and Science
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Lethbridge, Alta. : University of Lethbridge, Dept. of Geography and Environment
Preliminary findings from previous research into the thermal biological characteristics of mountain arthropods have determined that temperature plays a critical role in the emergence timing, growth and development rates, dispersal, fecundity, and mortality of these taxa. However, a disconnect currently exist with regards to the application of this lab derived data to real world environments as current meteorological models lack the sophistication and resolution to describe the thermal conditions experienced by surface-dwelling arthropods. The aim of this thesis is to investigate thermal distribution across a temperate mountain landscape in southern Alberta with the goal of contextualizing this information in a manner which was relevant to these taxa. As a result, average air and surface temperature models were created on annual and monthly time scales using in-situ measurements as input data for a variety of interpolation methods employed in Arc GIS Pro (version 2.9.1). Temperature models were then used to delineate thermally defined ecosystems in which overwintering suitability was determined as a by-product of the severity, duration, and frequency of cold exposure events while summer suitability was determined by the number of net growing days experienced under threshold temperatures of 5 °C, 8 °C, and 10 °C. In this environment, surface temperatures ranged from -21.17 °C to 51.18 °C, sub zero temperatures persisted for as many as 214 consecutive days, as many as 45 freeze-thaw cycles occurred within a single calendar year and a range of 107 to 172 average net growing days over 5 °C were recorded. To compliment this meteorological investigation, this document also serves as a first-hand account of the composition, abundance, and distribution of 35 families of surface-dwelling arthropods present within Castle Provincial Park. Several rare and endemic species belonging to these families such as Cyphoderris monstrosa and Grylloblatta Camodeiformis were also documented. Finally, inferences as to the thermal biological characteristics of these taxa are made based on the locations where they were collected, and estimations are made as to how the distribution of thermally suitable habitat for these creatures may change in accordance with future climate projections.
Microclimate , Arthropod , Mountain , Geographic distribution , Overwintering , Thermal offset , Refugia , Mountain arthropods , Surface-dwelling , Thermal distribution , Castle Provincial Park