Community Ecology

COMMUNITIES with Microtus tend to be structurally simple, usually grasslands or tundra, and to have no more than two species of Microtus and rarely more than six species of small mammals. Microtus often dominates both numerically and in total small mammal biomass, especially at higher latitudes. The small mammal community is most influenced by Microtus through its fluctuations in density, and thus also in biomass, by its relatively high level of diurnal activity, and by its year-round activity. Other species of small mammals may be adversely affected because Microtus usually is larger and behaviorally dominant and also because the mere presence of Microtus may focus predators on the area, especially during periods of high density. As generalized herbivores, primarily on grasses and herbs, Microtus has the potential to alter plant communities, either by selectively harvesting some species or through stimulating growth by grazing. Scarcely anything is known about the role Microtus plays in plant and small mammal communities, so both descriptive and experimental studies can make significant contributions to an understanding of the role and impact Microtus has on its communities

Neotoma alleni

Neotoma alleni Merriam, 1892 Allen’s Woodrat Neotema alleni Merriam, 1892:168. Type locality Manzanillo, Colima. Hodomys vetulus Merriam, 1894:236. Type locality Tehuacan, Puebla

Obituary: J. Knox Jones, Jr., 1929-1992

J. Knox Jones, Jr., was born in Lincoln, Nebraska, March 16, 1929, the eldest of the three sons of Virginia Bowen Jones and James Knox Jones. Knox passed away at his home in Lubbock, Texas, on November 15, 1992, after a two-year battle with cancer

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Multi-messenger Observations of a Binary Neutron Star Merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ∼ 1.7 {{s}} with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of {40}-8+8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 {M}ȯ . An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ∼ 40 {{Mpc}}) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ∼10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ∼ 9 and ∼ 16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta.</p

\u3ci\u3eNeotoma alleni\u3c/i\u3e

Neotoma alleni Merriam, 1892 Allen’s Woodrat. Neotema alleni Merriam, 1892:168. Type locality Manzanillo, Colima. Hodomys vetulus Merriam, 1894:236. Type locality Tehuacan, Puebla

Osteological Considerations and Aging Methods of Wildtrapped Mink

A total of 126 mink carcasses was collected in northwestern Kansas during two successive trapping seasons. The eyes of each animal were immediately preserved in 10 percent formalin and the carcasses cooked and cleaned for preservation as partial skeletons. The dry-lens-weight aging method was attempted and selected weights and measurements were taken on the skeletal material. The dry-lens-weight method indicated continuous lens growth. However, deterioration of the lenses and overlap between the age groups rendered the method unsuccessful. The specimens were then placed into two age classes utilizing a combination of age indicators for females and baculum morphology for males. Other aging methods mentioned in recent literature were investigated with varying degrees of success. Four sex-age groups “juvenile females, adult females, juvenile males, and adult males “are used throughout the study. Comparisons were made between the four sex-age groups. It was found that size overlap exists between the sexes, that juvenile mink of both sexes are statistically smaller than adults, and that mink bones tend to gain weight after elongation has ceased. Sex and age rations of the research sample were noted and compared to ration of other researchers. On this basis it appears that age composition and population density are not stable from year to year. Fluctuations may be related to summer weather conditions affecting reproductive success

Dynamics of small mammal populations at the Cottonwood and Osage sites, 1972

May 1974.On cover: Grassland Biome, Ecosystem analysis studies, U.S. International Biological Program.Includes bibliographical references (pages 40-41)