Quantifying the Effects of Herbivores and Climate Change on Arctic Tundra Carbon Cycling ...
The arctic tundra has been warming disproportionately faster than the global mean. Although the tundra has historically been a carbon sink, the current state of its carbon balance is highly uncertain. Large warming induced changes to tundra ecosystems complicate our ability to model tundra carbon cy...
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Columbia University
2021
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| Online Access: | https://dx.doi.org/10.7916/d8-st6n-1q29 https://academiccommons.columbia.edu/doi/10.7916/d8-st6n-1q29 |
| Summary: | The arctic tundra has been warming disproportionately faster than the global mean. Although the tundra has historically been a carbon sink, the current state of its carbon balance is highly uncertain. Large warming induced changes to tundra ecosystems complicate our ability to model tundra carbon cycling. In this dissertation I explore the impact of herbivores on dry heath vegetation and carbon flux, herbivore impact on dry heath tundra canopy, and lastly, the impact higher vegetation has on the conditions under which the tundra transitions from a carbon sink to a carbon source. Chapter 1 presents a study on the impact long term herbivore absence has on dry heath tundra. I measured vegetation cover, abundances of plant growth forms and carbon flux. I demonstrate the herbivore exclusion in this tundra ecosystem results in higher vegetation abundance and greater carbon uptake. Moreover, under average environmental conditions during the measurement period, I show that excluding herbivores resulted in net carbon ... |
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