The Somatic Chromosomes of Some North American Marmots (Sciuridae), with Remarks on the Relationships of Marmota browerii Hall and Gilmore

Karyotypes are defined for two nearctic species of marmots, Marmota olympus (2n = 40) and M. vancouverensis (2n = 42), and supplemental information is included on the karyotypes of M. flaviventris, M. monax ochracea, and M. marmota. The six North American species of Marmota (NF = 66) comprise a distinct group as compared with the middle Asian species (NF = 70) for which the karyotypes are known. Karyologic findings and zoogeographic evidence based upon the distribution of two nearctic species of host-specific cestodes indicate that M. broweri, in northern Alaska, is a pre-Würm relict. Its affinities appear to be with the North American caligata-group rather than with the northeastern Siberian M. camtschatica. The occurrence on M. broweri of the Asian flea, Oropsylla silantiewi, has not been explained. Some ecological and behavioral characteristics of M. broweri are briefly described and compared with those of other species. Family groups of M. broweri hibernate together in single winter dens that are plugged at the entrance; copulation takes place before the animals emerge from the winter den, near mid-May; face-glands are utilized in marking of territory. French abstract: Les auteurs définissent les caryotypes de deux espèces néarctiques de marmottes, Marmota olympus (2n=40) et M. vancouverensis (2n=42), et donnent des précisions sur les caryotypes de M. flaviventris, M. monax ochracea et M. marmota. Les six especes de Marmota (NF=66) d'Amérique du Nord forment un groupe distinct des espèces d'Asie centrale (NF=70) dont Ie caryotype est connu. Les données caryologiques et les preuves zoogéographiques basées sur la répartition de deux espèces néarctiques de cestodes spécifiques de I'hôte démontrent que M. broweri, dans l'Alaska septentrional, est une relicte du pré-Würm. Elle semble avoir plus d'affinités avec Ie groupe nord américain de caligata qu'avec M. camtschatica du nord de la Sibérie. La présence sur M. broweri de la puce asiatique, Oropsylla silantiewi, n'est pas expliquée. Quelques caractéristiques écologiques et éthologiques de M. broweri sont décrites brièvement et comparées avec celles d'autres espèces. Les groupes familiaux de M. broweri hibernent dans un meme terrier dont l'entrée est bouchée; la copulation à lieu avant que les animaux sortent de leur abri hivernal, it la mi-mai ; ils se servent de leurs glandes faciales pour marquer leur territoire.

Temporal and Spatial Variations of Ions, Isotopes and Agricultural Contaminants in Surface Waters and Groundwater of Nebraska's Rainwater Basin Wetland Region

The wetlands of south-central Nebraska’s Rainwater Basin region are considered of international importance as a habitat for millions of migratory birds, but are being endangered by agricultural practices. The Rainwater Basin extends across 17 counties and covers 4,000 square miles. The purpose of this study was to assemble baseline chemical data for several representative wetlands across the Rainwater Basin region, and determine the use of these chemical data for investigating groundwater recharge. Eight representative wetlands were chosen across the Rainwater Basin to monitor surface and groundwater chemistry. At each site, a shallow well and deep well were installed and sampled once in the summer of 2009 and again in the spring of 2010. Wetland surface water was sampled monthly from April, 2009 to May, 2010. Waters were analyzed for major ions, nutrients, pesticides and oxygen-18 and deuterium isotopes at the University of Nebraska Water Sciences Laboratory. Geochemical analysis of surface waters presents a range of temporal and spatial variations. Wetlands had variable water volumes, isotopic compositions, ion chemistries and agricultural contaminant levels throughout the year and, except for a few trends, theses variations cannot be predicted with certainty year-to-year or wetland-to-wetland. Isotopic compositions showed evaporation was a contributor to water loss, and thus, did impact water chemistry. Surface water nitrate concentrations ranged from <0.10 to 4.04 mg/L. The nitrate levels are much higher in the groundwater, ranging from <0.10 to 18.4 mg/L, and are of concern because they are found above the maximum contaminant level (MCL) of 10 mg/L. Atrazine concentrations in surface waters ranged from <0.05 to 10.3 ppb. Groundwater atrazine concentrations ranged from <0.05 to 0.28 ppb. The high atrazine concentrations in surface waters are of concern as they are above the MCL of 3 ppb, and the highest levels occur during the spring bird migration. Most sampled groundwaters had detectable tritium indicating a mix of modern (<5 to 10 years old) and submodern (older than 1950s) recharge. The groundwater also had differences in chemical and isotope composition, and in some cases, increased nitrate concentrations, between the two sampling periods. Modern groundwater tritium ages and changes in groundwater chemical and isotopic compositions may indicate connections with surface waters in the Rainwater Basin.