Soil nematode community response to climate change and associated alterations to precipitation and vegetation
| dc.contributor.author | Ankrom, Katharine Elizabeth, author | |
| dc.contributor.author | Wall, Diana, advisor | |
| dc.contributor.author | Fonte, Steven, committee member | |
| dc.contributor.author | Knapp, Alan, committee member | |
| dc.contributor.author | Lockwood, Dale, committee member | |
| dc.date.accessioned | 2021-09-06T10:25:58Z | |
| dc.date.available | 2021-09-06T10:25:58Z | |
| dc.date.issued | 2021 | |
| dc.description.abstract | Understanding of the belowground grassland response to climate change is much more limited than aboveground responses. This disparity in knowledge is partially due to the vast diversity in species in belowground ecosystems and the overwhelming task of identifying the roles and processes associated with each. Soil nematodes represent the most abundant soil fauna on earth and are exceptional in that they occupy every trophic level, contain multiple life history strategies, and are relatively easy to extract and identify from soil. Moreover, nematode activity (e.g. feeding) directly regulates the size and function of fungal and bacterial populations thus indirectly impacting the rates of carbon and nitrogen turnover. Determining the abundance of each nematode genera in a soil sample can allow for calculation of ecological indices that can further explore the trophic complexity, energy pathways, and both the sensitivity and resilience of soil nematode communities to stress and disturbance. Therefore studying soil nematode communities provides a means for gaining important insights about poorly understood belowground responses to altered environments. The aim of this dissertation is to expand our knowledge of soil community dynamics in grasslands in the face of extreme precipitation changes and possible vegetation shifts. In the first chapter of this dissertation, I introduce the importance of grassland ecosystems and the challenges looming from climate change. Next I highlight the two scenarios in which my research is based and give the details on how utilizing nematode data can answer these questions. The second chapter of this dissertation addresses the question: Can nematode trophic analysis reveal associations between vegetation cover types? This study revealed striking differences in the abundances of fungivores and the combined omnivore/predator trophic groups found under the dominant grass compared to both an invasive forb and bare soil cover types. In the third chapter a focus on the most well-studied nematode trophic group; plant parasitic nematodes (PPN) sought to determine if different feeding strategies lead to distinct responses in precipitation treatments across three grassland sites. This research aimed to understand if host plants will have an increased burden harboring greater PPN populations along with increased water stress. Our results showed that the response of PPN feeding type abundance, functional guild, and herbivory index to precipitation was site dependent, a finding not previously studied. Building on the findings of Chapter 3, Chapter 4 utilized the entire soil nematode community and calculated indices to see how the different grassland types; arid, semiarid, and mesic would respond to the same precipitation treatments. Specifically, I tested if nematodes would be effective indicators of the soil community to changes in rainfall events. The results of this study showed the importance of genera level resolution and suggests that the sensitivity of these indices allows for ecological interpretation of belowground function and status in a natural setting. A finding that is especially pertinent, as these grasslands will not respond to precipitation alterations similarly and will therefore require unique mitigation strategies. In summary, with both field and laboratory work my PhD project has: 1) found associations between nematode trophic group abundance and vegetation cover types; 2) revealed the different response of grassland ecto-and endoparasitic nematodes to manipulated rainfall across a precipitation gradient; 3) quantified the herbivory index of a PPN population in response to precipitation treatments across three grassland sites; and 4) demonstrated the sensitivity of nematode ecological indices and found indicator genera in three grassland sites with manipulated precipitation treatments. Together these results bolster our knowledge of how soil nematode communities will respond to climate change and highlight their potential role for monitoring and influencing grassland ecosystem dynamics into the future. | |
| dc.format.medium | born digital | |
| dc.format.medium | doctoral dissertations | |
| dc.identifier | Ankrom_colostate_0053A_16636.pdf | |
| dc.identifier.uri | https://hdl.handle.net/10217/233791 | |
| dc.language | English | |
| dc.language.iso | eng | |
| dc.publisher | Colorado State University. Libraries | |
| dc.relation.ispartof | 2020- | |
| dc.rights | Copyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright. | |
| dc.title | Soil nematode community response to climate change and associated alterations to precipitation and vegetation | |
| dc.type | Text | |
| dcterms.rights.dpla | This Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). | |
| thesis.degree.discipline | Biology | |
| thesis.degree.grantor | Colorado State University | |
| thesis.degree.level | Doctoral | |
| thesis.degree.name | Doctor of Philosophy (Ph.D.) |
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