Factors affecting insulation quality of lichen (Usnea barbata) as nest material used by the woodland dormouse

Olajide, Ruth Oluwafem
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Nest insulation quality is crucial in the selection of nest materials for nest construction by small endotherms that experience heat loss at the critical time of the season when the ambient temperature is low. The primary function of these nests is to increase insulation thereby reducing heat loss to enhance thermoregulatory benefits of the animals and their offspring. The overall aim of my project was to study factors affecting the insulation properties of the old man’s beard lichen (Usnea barbata) a nesting material found in a majority of artificial nest boxes and tree cavities utilized by African woodland dormice (Graphiurus murinus). I performed laboratory experiments to investigate the cooling rates of nests made from variety of nesting materials, under various ambient temperatures, and the effects of mass and moisture content on those cooling rates. I found that there are differences in the insulation properties of nesting materials. Feathers were the best insulators followed by fresh lichen; dry grass and paper ranked the worst. I also revealed that the quantity of lichen inside the nest had a significant effect on insulation. Heavier nests with more lichen had low cooling rates, thus thermal benefit. I changed the moisture content of the lichen. I found that when lichen nest material is humid, the cooling rates are low, thus high insulation, and wet lichen is the worst at insulation. Variation in ambient temperatures also had significant effects on nest cooling rates, even at high ambient temperatures. I conclude that fresh lichen provides insulation in the nests of woodland dormice. Woodland dormice may highly depend on available, and abundant fresh lichen in the forest because of the insulation and thermal benefits of lichen
A research report submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg in partial fulfilment of the requirements for the degree of Master of Science, 2020