http://hdl.handle.net/2142/160 (No description provided) Search the Channel search https://www.ideals.uiuc.edu/simple-search http://hdl.handle.net/2142/173 Title: Site Map for Data and Publications of the Long term vole demographic data <br/> <br/>Authors: Getz, Lowell L. <br/> <br/>Abstract / Summary: Site map to the long term demographic data on voles. <br/> <br/>Keywords: Microtus pennsylvanicus; Microtus ochrogaster; Voles; Demographic data http://hdl.handle.net/2142/172 Title: Data and Procedures - Long term vole demographic data files <br/> <br/>Authors: Getz, Lowell L. <br/> <br/>Abstract / Summary: This is the main page for two sets of long-term data files. One set includes data obtained for the prairie vole, Microtus ochrogaster, and the meadow vole, M. pennsylvanicus, in three habitats (alfalfa, bluegrass, and tallgrass prairie) by trapping at monthly intervals for 25 years. The other data are for the prairie vole, from a study in which the population was trapped twice weekly for 63 months. In addition, there are files giving monthly estimates of population density of the short-tailed shrew, Blarina brevicauda, for each of the three habitats. Each of these data sets are available separately within IDEALS. <br/> <br/>Keywords: Microtus pennsylvanicus; Microtus ochrogaster; Demographic data; Voles http://hdl.handle.net/2142/171 Title: Published paper appendices based on long term vole demographic data <br/> <br/>Authors: Getz, Lowell L.; Hofmann, Joyce E.; McGuire, Betty; Oli, Madan K. <br/> <br/>Abstract / Summary: This file contains appendices referenced in the listed papers published in the indicated journals. These are the supporting detailed analyses for the statistical results presented in the papers. The appendices are numbered consecutively. <br/> <br/>Keywords: Microtus pennsylvanicus; Microtus ochrogaster; Demographic data; Voles http://hdl.handle.net/2142/170 Title: Unpublished Manuscripts from Vole Data <br/> <br/>Authors: Getz, Lowell L. <br/> <br/>Abstract / Summary: Included here are drafts of manuscripts that were rejected. Many have been revised and published in a different format. For all papers published from these datasets, see http://www.life.uiuc.edu/getz/vitae.html. <br/> <br/>Keywords: Microtus pennsylvanicus; Microtus ochrogaster http://hdl.handle.net/2142/169 Title: Manuscript - Dynamics of sympatric vole populations: influence of food resources and interspecific competition <br/> <br/>Authors: Getz, Lowell L.; Hofmann, Joyce E.; McGuire, Betty; Oli, Madan K. <br/> <br/>Abstract / Summary: Abundance of food resources and interspecific competition can significantly influence the dynamics of arvicoline rodent populations. We studied responses of Microtus ochrogaster and M.pennsylvanicus to supplemental food and interspecific competition in bluegrass (marginal food habitat) and tallgrass prairie (low food habitat). Removal experiments were conducted to study reciprocal interspecific interactions between the two species in bluegrass and the effects of M. pennsylvanicus on M. ochrogaster in tallgrass. Mean population densities and patterns of fluctuation of M. ochrogaster did not differ between supplementally fed and control sites in either bluegrass or tallgrass habitats. However, amplitudes of fluctuation and proportion of reproductive females were higher in supplementally fed than in control bluegrass sites for this species. Mean population densities of M. pennsylvanicus were slightly higher in supplementally fed than in control tallgrass sites; the addition of food to bluegrass, however, did not result in higher population densities for this species. Population densities of M. ochrogaster and M. pennsylvanicus in bluegrass were not suppressed by the presence of the other species. Although survival of M. ochrogaster was lower in the presence of M. pennsylvanicus, there was no negative effect on reproduction. Presence of M. ochrogaster did not adversely affect either survival or reproduction of M. pennsylvanicus in bluegrass. Although M. pennsylvanicus appeared to exert a strong suppressing effect on population densities of M. ochrogaster in tallgrass, neither survival nor reproduction of M. ochrogaster was lower when M. pennsylvanicus was present in this habitat. Similar results were observed from interspecific correlations between population densities, survival and reproduction of the two species during a 25-year demographic study in bluegrass and tallgrass. We conclude that food resources and interspecific competition do not play a major role in driving the dynamics of M. ochrogaster and M. pennsylvanicus populations in our study sites. <br/> <br/>Keywords: Demography; Food resources; Microtus ochrogaster; Microtus pennsylvanicus; Voles; Interspecific competition http://hdl.handle.net/2142/168 Title: Manuscript - Home range dynamics of sympatric vole populations: influence of food resources, population density, interspecific competition, and mating system <br/> <br/>Authors: Getz, Lowell L.; Hofmann, Joyce E.; McGuire, Betty; Oli, Madan K. <br/> <br/>Abstract / Summary: We studied variation in home range size in fluctuating populations of Microtus ochrogaster and M. pennsylvanicus in alfalfa, bluegrass and tallgrass habitats over a 25-year period in east-central Illinois. The three habitats differed in food availability and vegetative cover. Home range indices of both species were complexly related to abundance of food resources. Home ranges of M. ochrogaster were smallest in the high food habitat (alfalfa), largest in the low food habitat (tallgrass) and intermediate in medium food habitat (bluegrass). M. pennsylvanicus home ranges were largest in the low food habitat, but did not differ between the high and intermediate food habitats. M. ochrogaster did not have smaller home ranges in supplementally fed medium and low food habitats; those of M. pennsylvanicus were smaller only in the low food habitat. Home ranges of M. ochrogaster were compressed only at population densities above 100/ha, irrespective of food levels; those of M. pennsylvanicus were smaller at high densities only in medium and low food habitats. Presence of the other species did not influence size of home ranges of either species. Withinhabitat seasonal variation in home range indices indicated a confounding response to cover (prey risk) and food. Home ranges of all age classes of M. pennsylvanicus were larger than those of M. ochrogaster in all three habitats. There was no obvious relationship between home range sizes of adult males and females in relation to the mating system of each species. For both species in all three habitats, home ranges of adult males were larger than those of adult females. <br/> <br/>Keywords: Voles; Home range; Microtus ochrogaster; Microtus pennsylvanicus http://hdl.handle.net/2142/167 Title: Manuscript - Demography of fluctuating vole populations: Are changes in demographic variables consistent across individual cycles, habitats and species? <br/> <br/>Authors: Getz, Lowell L.; Hofmann, Joyce E.; McGuire, Betty; Oli, Madan K. <br/> <br/>Abstract / Summary: We analyzed monthly survival rates, persistence of young, reproduction, recruitment of young, immigration rates, body mass, and sex ratio for fluctuating sympatric populations of Microtus ochrogaster and M. pennsylvanicus in alfalfa, bluegrass and tallgrass over 25 years. M. ochrogaster underwent 13 population cycles in alfalfa, 12 in bluegrass and five in tallgrass. M. pennsylvanicus displayed five cycles in alfalfa, nine in bluegrass and was acyclic in tallgrass. Among the demographic variables considered, only increased survival and persistence of young were associated consistently with the increase phase of population cycles in both species. Survival rates, persistence of young and reproduction of M. ochrogaster were lower during the decline than during the increase phase in alfalfa and bluegrass, but not in tallgrass. There were no demographic differences between the decline and increase phases for M. pennsylvanicus in either alfalfa or bluegrass. Most differences in demographic variables within phases among habitats involved survival and explained among-habitat demographic differences of each species. Differences in demographic variables within phases between species also mainly involved survival; these differences were consistent with differences in demography of the two species in alfalfa. Overall, our data indicate that changes in survival were most important in determining patterns of fluctuation in our study populations. <br/> <br/>Keywords: Vole populations; Illinois http://hdl.handle.net/2142/166 Title: Manuscript - Vole population fluctuations: factors affecting peak densities and intervals between peaks <br/> <br/>Authors: Getz, Lowell L.; Hofmann, Joyce E.; McGuire, Betty; Oli, Madan K. <br/> <br/>Abstract / Summary: Factors associated with initiation of population cycles of Microtus ochrogaster and M. pennsylvanicus were studied in alfalfa, bluegrass and tallgrass habitats for 25 years. For both species, increased survival appeared to be the most important factor associated with initiation of a population cycle during a given year. There was no difference in reproduction the previous winter or during spring (both species) and autumn (M. ochrogaster) of cycle and non-cycle years. Weather differences, including episodes of extreme conditions, were not associated with cycle and non-cycle years. There was no indication that cyclic phenomena were a result of habitat degradation owing to high densities during peak phases. We found no relationship between peak densities and rate of decline, length and extent of the decline, population density during the subsequent trough, or the interval until the next cycle. Population cycles appeared to be initiated by relaxation of predation pressure which occurred erratically across years. <br/> <br/>Keywords: Microtus pennsylvanicus; Microtus ochrogaster; Prairie vole; Meadow vole; population cycles http://hdl.handle.net/2142/165 Title: Manuscript - Vole population dynamics: factors affecting amplitudes of fluctuation <br/> <br/>Authors: Getz, Lowell L.; Hofmann, Joyce E.; McGuire, Betty; Oli, Madan K. <br/> <br/>Abstract / Summary: Factors affecting amplitudes of fluctuation during 39 population cycles of Microtus ochrogaster and 20 cycles of M. pennsylvanicus were studied in alfalfa, bluegrass and tallgrass habitats over a 25-year period. <br/> <br/>Keywords: Microtus pennsylvanicus; Microtus ochrogaster; Prairie vole; Meadow vole http://hdl.handle.net/2142/164 Title: Manuscript - Population dynamics of the northern short-tailed shrew, Blarina brevicauda: insights from a 25-year study <br/> <br/>Authors: Getz, Lowell L.; Hofmann, Joyce E.; McGuire, Betty; Oli, Madan K. <br/> <br/>Abstract / Summary: Population demography of the northern short-tailed shrew, Blarina brevicauda, was studied for 25 years in bluegrass, alfalfa, and tallgrass habitats in east-central Illinois. The population in bluegrass had higher over-winter population density, began increasing earlier in the year, peaked earlier in the year, had higher mean monthly population densities and amplitudes of fluctuation, and remained higher longer than did populations in alfalfa and tallgrass. Survival rates and persistence were greater in bluegrass and tallgrass than in alfalfa. The species displayed annual population fluctuations with little variation in amplitude among years in all three habitats. Seasonal reproduction appeared responsible for the annual fluctuations. Survival did not vary in relation to season, but was positively correlated with annual peak densities whereas reproduction was not. There was no correlation between population densities of voles during April-August and annual peak densities of B. brevicauda. We conclude that annual fluctuations in B. brevicauda are driven by seasonal reproduction, while variation in mortality, most likely from predation, may explain differences in the amplitudes of annual peaks. <br/> <br/>Keywords: northern short-tailed shrew; Blarina brevicauda