The Experts below are selected from a list of 525 Experts worldwide ranked by ideXlab platform

Gregory F Grether - One of the best experts on this subject based on the ideXlab platform.

  • body size not phylogenetic relationship or residency drives interspecific dominance in a little pocket mouse community
    Animal Behaviour, 2018
    Co-Authors: Rachel Y Chock, Debra M Shier, Gregory F Grether
    Abstract:

    The role of interspecific aggression in structuring ecological communities can be important to consider when reintroducing endangered species to areas of their historic range that are occupied by competitors. We sought to determine which species is the most serious interference competitor of the endangered Pacific pocket mouse, Perognathus longimembris pacificus, and more generally, whether interspecific aggression in rodents is predicted by body size, residency status or phylogenetic relatedness. We carried out simulated territory intrusion experiments between P. longimembris and four sympatric species of rodents (Chaetodipus fallax, Dipodomys simulans, Peromyscus maniculatus, Reithrodontomys megalotis) in a field enclosure in southern California sage scrub habitat. We found that body size asymmetries strongly predicted dominance, regardless of phylogenetic relatedness or the residency status of the individuals. The largest species, D. simulans, was the most dominant while the smallest species, R. megalotis, was the least dominant to P. longimembris. Furthermore, P. longimembris actively avoided encounters with all species, except R. megalotis. One management recommendation that follows from these results is that P. longimembris should not be reintroduced to areas with high densities of D. simulans until further research is carried out to assess the fitness consequences of the interactions. Our finding that the species least similar in body size is the most serious interference competitor of P. longimembris highlights an important distinction between interference and exploitative competition in rodent communities.

Barbour, Roger W. - One of the best experts on this subject based on the ideXlab platform.

Rachel Y Chock - One of the best experts on this subject based on the ideXlab platform.

  • body size not phylogenetic relationship or residency drives interspecific dominance in a little pocket mouse community
    Animal Behaviour, 2018
    Co-Authors: Rachel Y Chock, Debra M Shier, Gregory F Grether
    Abstract:

    The role of interspecific aggression in structuring ecological communities can be important to consider when reintroducing endangered species to areas of their historic range that are occupied by competitors. We sought to determine which species is the most serious interference competitor of the endangered Pacific pocket mouse, Perognathus longimembris pacificus, and more generally, whether interspecific aggression in rodents is predicted by body size, residency status or phylogenetic relatedness. We carried out simulated territory intrusion experiments between P. longimembris and four sympatric species of rodents (Chaetodipus fallax, Dipodomys simulans, Peromyscus maniculatus, Reithrodontomys megalotis) in a field enclosure in southern California sage scrub habitat. We found that body size asymmetries strongly predicted dominance, regardless of phylogenetic relatedness or the residency status of the individuals. The largest species, D. simulans, was the most dominant while the smallest species, R. megalotis, was the least dominant to P. longimembris. Furthermore, P. longimembris actively avoided encounters with all species, except R. megalotis. One management recommendation that follows from these results is that P. longimembris should not be reintroduced to areas with high densities of D. simulans until further research is carried out to assess the fitness consequences of the interactions. Our finding that the species least similar in body size is the most serious interference competitor of P. longimembris highlights an important distinction between interference and exploitative competition in rodent communities.

Van Zee, Justin W. - One of the best experts on this subject based on the ideXlab platform.

  • Current Status of the Plains Pocket Mouse, Perognathus flavescens, in Iowa
    UNI ScholarWorks, 1996
    Co-Authors: Wilson, Gregory M., Bowles, John B., Van Zee, Justin W.
    Abstract:

    Published and unpublished accounts of the plains pocket mouse (Perognathus flavescens) were utilized to document the existence of extant populations and to summarize and report additional data about the biology of this state endangered Iowa species. Populations of P. flavescens exist in western (Harrison, Monona, and Plymouth counties) and extreme eastern (adjacent portions of Louisa and Muscatine counties) Iowa, the latter of which represents the eastern-most record for the species in North America. In addition, we document a new locality for P. flavescens from the interior of the state (Benton County). All known populations of P. flavescens in Iowa occur in grassland habitats on well-drained substrates (i.e., loess, sandy loam, and sandy soils). Reproductive data suggested that P. flavescens in Iowa have at least two litters (early spring and late summer) of three to eight young. We hope this paper will stimulate additional research that will lead to a better understanding of the general distribution and biology of P. flavescens in Iowa

Wyatt, Megan Renee - One of the best experts on this subject based on the ideXlab platform.

  • Using 2D Dental Geometric Morphometrics to Identify Modern Chaetodipus and Perognathus Specimens (Rodentia, Heteromyidae)
    University of Oregon, 2020
    Co-Authors: Wyatt, Megan Renee
    Abstract:

    46 pagesThe Heteromyidae (pocket mice and kangaroo rats) are a group of extant small rodents abundant in North American Cenozoic fossil assemblages. Two genera of heteromyids, Chaetodipus and Perognathus, share similar tooth morphology whose fossils are distinguished using skull shape and body size estimates. Previous genetic studies show these extant genera likely diverged in the early Miocene (~20 million years ago). However, the Chaetodipus fossil record starts in the Pleistocene (~2 million years ago) while the Perognathus fossil record begins in the middle Miocene, near the time suggested by molecular divergence. Other studies found these two genera are not distinguishable from each other using descriptive dental morphology alone. In this study, I asked whether two-dimensional geometric morphometrics on complete dentition and isolated premolars can accurately identify Chaetodipus and Perognathus specimens at the genus and species-level. I developed a landmarking scheme based on features that are consistent through wear, are recognizable in the fossil record, and could be subset for analyses on individual molars. I landmarked the occlusal surface of the upper and lower tooth rows of modern Chaetodipus (n=83) and Perognathus specimens (n=80), including 12 of the 26 extant species across the two genera. We used the R packages “geomorph” and “Morpho” to run a canonical variates analysis to investigate whether principal component variation could predict known taxonomic identifications. The morphospace using complete dentition can identify specimens to genus with 90-92% accuracy and to species with more variable accuracy. Similarities in body size and biogeographic ranges explained genus-level misidentification while phylogenic relationships explained species-level misidentification. Specifically, Perognathus parvus, the largest Perognathus species in the analysis, was most frequently misidentified as Chaetodipus. I found an isolated premolar provides sufficient information for genus-level identification (69%-84% accuracy), but not for species-level identification (26%-56% accuracy). The morphospace suggests the anterior-posterior length and transverse width ratios of the premolars are diagnostic for genus identification. This morphospace of modern specimens can be used to identify the fossil dentition of Chaetodipus and Perognathus specimens already in museum collections and refine our existing knowledge of heteromyid evolutionary history

  • Using 2D Dental Geometric Morphometrics to Identify Modern Chaetodipus and Perognathus Specimens (Rodentia, Heteromyidae)
    University of Oregon, 2020
    Co-Authors: Wyatt, Megan Renee
    Abstract:

    44 pages. A thesis presented to the Department of Department of Biology, the Department of Earth Sciences and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Spring 2020.The Heteromyidae (pocket mice and kangaroo rats) are a group of extant small rodents abundant in North American Cenozoic fossil assemblages. Two genera of heteromyids, Chaetodipus and Perognathus, share similar tooth morphology whose fossils are distinguished using skull shape and body size estimates. Previous genetic studies show these extant genera likely diverged in the early Miocene (~20 million years ago). However, the Chaetodipus fossil record starts in the Pleistocene (~2 million years ago) while the Perognathus fossil record begins in the middle Miocene, near the time suggested by molecular divergence. Other studies found these two genera are not distinguishable from each other using descriptive dental morphology alone. In this study, I asked whether two-dimensional geometric morphometrics on complete dentition and isolated premolars can accurately identify Chaetodipus and Perognathus specimens at the genus and species-level. I developed a landmarking scheme based on features that are consistent through wear, are recognizable in the fossil record, and could be subset for analyses on individual molars. I landmarked the occlusal surface of the upper and lower tooth rows of modern Chaetodipus (n=83) and Perognathus specimens (n=80), including 12 of the 26 extant species across the two genera. We used the R packages “geomorph” and “Morpho” to run a canonical variates analysis to investigate whether principal component variation could predict known taxonomic identifications. The morphospace using complete dentition can identify specimens to genus with 90-92% accuracy and to species with more variable accuracy. Similarities in body size and biogeographic ranges explained genus-level misidentification while phylogenic relationships explained species-level misidentification. Specifically, Perognathus parvus, the largest Perognathus species in the analysis, was most frequently misidentified as Chaetodipus. I found an isolated premolar provides sufficient information for genus-level identification (69%-84% accuracy), but not for species-level identification (26%-56% accuracy). The morphospace suggests the anterior-posterior length and transverse width ratios of the premolars are diagnostic for genus identification. This morphospace of modern specimens can be used to identify the fossil dentition of Chaetodipus and Perognathus specimens already in museum collections and refine our existing knowledge of heteromyid evolutionary history