Granivory and Granivores in Native Grasslands and Agropyron Cristatum Stands in the Northern Great Plains

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dc.contributor.advisor Wilson, Scott
dc.contributor.author Radtke, Troy Mark
dc.date.accessioned 2012-08-31T16:42:36Z
dc.date.available 2012-08-31T16:42:36Z
dc.date.issued 2012-05
dc.identifier.uri http://hdl.handle.net/10294/3563
dc.description A Thesis Submitted to the Faculty of Graduate Studies and Research in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Biology, University of Regina, xv, 160 l. en_US
dc.description.abstract Agropyron cristatum (crested wheatgrass) is a management concern in the northern Great Plains because of the low plant biodiversity and high stability in A. cristatum stands. Small consumers have the potential to contribute to A. cristatum invasion and stability through granivory and herbivory. Little is known about ant species composition in the Northern Great Plains. I quantified seed removal rates, granivore seed preferences, and ant communities in paired native grasslands and A. cristatum stands. I examined temporal variation in vegetation factors that influence granivory rates. Finally, I determined the relationship between seed size and vertebrate granivore preferences in herbaceous and woody communities, and I sampled ants to determine species composition and how vegetation parameters influence ant communities. Granivory rates did not differ between native grasslands and A. cristatum stands. Forb cover and season were important predictors of granivory rates in 2009, with higher granivory later in the growing season and at sites with greater cover of forbs. In 2010, there were no important predictors of granivory rates. Granivory rates in A. cristatum stands were similar to those in native grasslands, possibly because the vegetative cover and litter depth of A. cristatum stands was similar to that of native grasslands. Granivores did not prefer native seeds to exotic ones and showed little seed preference. A review of vertebrate granivore seed size preferences revealed that granivores often prefer relatively small seeds in forests and relatively large seeds in herbaceous communities. However, the absolute size of preferred seeds in each community is often similar. Ant species richness was similar between native grasslands and A. cristatum stands, while ant species composition differed between the two vegetation types. However, there were no differences in total ant abundance or the abundance of functional groups between native grasslands and A. cristatum stands. Ant abundance increased with the covers of bare ground and litter. Granivory was related to variables such as forb cover and bare ground, which varied within both vegetation types. Yet, in spite of differences in plant species dominance and plant diversity between native grasslands and A. cristatum stands, there were few differences between the vegetation types in terms of granivory rates, granivore seed preferences or total ant abundance. en_US
dc.description.uri A Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy *, University of Regina. *, * p. en
dc.language.iso en en_US
dc.publisher Faculty of Graduate Studies and Research, University of Regina en_US
dc.subject.lcsh Granivores--Saskatchewan
dc.subject.lcsh Granivores--Montana
dc.subject.lcsh Grasslands--Saskatchewan
dc.subject.lcsh Grasslands--Montana
dc.subject.lcsh Crested wheatgrass--Seeds--Predators of--Saskatchewan
dc.subject.lcsh Crested wheatgrass--Seeds--Predators of--Montana
dc.subject.lcsh Ant communities--Saskatchewan
dc.subject.lcsh Ant communities--Montana
dc.title Granivory and Granivores in Native Grasslands and Agropyron Cristatum Stands in the Northern Great Plains en_US
dc.type Thesis en
dc.description.authorstatus Student en
dc.description.peerreview yes en
thesis.degree.name Doctor of Philosophy (PhD) en_US
thesis.degree.level Doctoral en
thesis.degree.discipline Biology en_US
thesis.degree.grantor University of Regina en
thesis.degree.department Department of Biology en_US
dc.contributor.committeemember Somers, Christopher
dc.contributor.committeemember Hardenbicker, Ulrike
dc.contributor.committeemember MacDougall, Andrew
dc.contributor.externalexaminer Bayne, Erin


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