Date of Award

4-2020

Degree Type

Thesis

Degree Name

Master of Science

Department

Biology; Interdisciplinary

Program

Integrated Biosciences

First Advisor/Chairperson

Dr. Alan Rebertus

Abstract

I investigated biogeochemical connections between woodland caribou (Rangifer tarandus caribou) herbivory, vegetation, soil fertility, and soil carbon cycling on the Slate Islands Provincial Park in Ontario, Canada. Woodland caribou are threatened in Ontario, and the caribou population on the Slate Islands has declined steeply since 2015. Northern Michigan University (NMU) and Ontario Ministry of Natural Resources and Forestry (OMNRF) ecologists established caribou and snowshoe hare (Lepus americanus) exclosures on the islands in 2006, and have routinely monitored the vegetation to study the effects of limiting herbivory.

This study explores the implications of limiting herbivory on soil fertility, carbon and nitrogen stocks, and CO2 respiration by using NMU/OMNRF exclosures. Spatial variability in soils is a major source of variation and was accounted for in the study design, which consisted of three sets of three co-located, randomized (3.65 x 3.65 m) control plots, caribou/snowshoe hare exclosures, and caribou-only exclosures. Significantly larger levels of soil phosphorus (ppm), CEC (meq 100 g-1), C:N ratios; soil CO2 (g m-2 d-1) respiration; total carbon stocks (Mg C ha -1), and total nitrogen stocks (Mg N ha -1) were detected in reference soils without at least 100 years of caribou herbivory pressures on a contained island ecosystem. After 12 years of exclosure, vegetation strongly recovered, but soil did not recover in that time frame.

Access Type

Open Access

Justification for Restricting Access

The purpose of the 5-year embargo for this paper is for publication. The worked contained within the thesis will be submitted for publication in a peer reviewed journal by 4/17/25. Some journals will not publish previously published material so the embargo will allow for publication without violating copyright issues.

Available for download on Thursday, April 17, 2025

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