Population Dynamics of Three Amphibian Species Across the Sheyenne National Grassland of Southeastern North Dakota

Concerns over worldwide declines of amphibians, including some to extinction, has increased the urgency for understanding how amphibians interact within local environments and across regional landscapes. Hypotheses for declines include anthropogenic destruction and fragmentation of amphibian habitat, introduction of exotic predators and competitors, increased ultraviolet (UV-B) irradiation, acid precipitation, environmental contamination by pollutants, harsh climatic conditions, over harvesting, and infectious disease. Three different types of models were developed for the northern leopard frog (Rana pipiens), gray tiger salamander (Ambystoma tigrinum diaboli), and gray tree frog (Hyla versicolor/chrysoscelis complex) populations inhabiting the Sheyenne National Grassland (SNG) in southeastern North Dakota. The SNG is a relatively large (283 km2) and contiguous piece of tallgrass prairie embedded in a landscape dominated by agriculture, though the predominant land use on the SNG is grazing by domestic livestock. Although amphibians often occur in a metapopulation typ~ structure where individual wetlands represent patches, continued fragmentation and isolation of habitat will cause populations to go extinct if colonization is not sufficient to offset local extinction. Because many factors may influence habitat use and occupancy of amphibian populations, best subsets logistic regression was used to develop occupancy and extinction models for these amphibian species using a whole suite of variables related to wetland hydroperiod, wetland isolation, patch quality, and landscape complementation

First Discovery of a Four-Egg Clutch for Mountain Plover (\u3ci\u3eCharadrius montanus\u3c/i\u3e) in Nebraska

On 27 May 2010, the first documented Mountain Plover nest in Nebraska to contain a clutch of four eggs was documented in a fallow strip of a dryland crop field in southern Kimball County. Mountain Plover typically have a clutch size of 3 eggs, though clutches with 1 and 2 eggs are observed in approximately 15% of nesting attempts (Knopf and Wunder 2006). Clutches with 4 eggs are rare and have been reported to occur in less than 1% of the population (Knopf and Wunder 2006). Five 4-egg clutches have been reported in Colorado and one in Montana (see Knopf and Wunder 2006 for details), but this was the first 4-egg clutch reported in Nebraska, and it was located after 11 years of intensive study in which a total of 598 Mountain Plover nests were located

Differential Use of Agricultural Fields and Rangeland Nesting Habitat by McCown’s Longspur (\u3ci\u3eCalcarius mccownii\u3c/i\u3e) and Chestnut-Collared Longspur (\u3ci\u3eCalcarius ornatus\u3c/i\u3e) in Western Nebraska

The Nebraska Natural Legacy Plan (NNLP) lists both McCown\u27s Longspur and Chestnut-collared Longspur as Tier I and Tier II species of conservation concern, respectively (Schneider et al. 2005). McCown\u27s Longspur is listed as a Tier I species (highest conservation priority) in Nebraska because of regional population declines (Schneider et al. 2005), and because it is also listed on the Partners in Flight WatchList (Fitzgerald and Pashley 2000). The breeding distribution of McCown\u27s Longspur in Nebraska is suggested to be the westernmost counties of the Panhandle (With 1994), although limited information on the breeding ecology of this species exists for Nebraska. In fact, Mollhoff (2001) recorded McCown\u27s nesting in only the westernmost Panhandle, specifically Kimball and Sioux Counties, although both geographic areas are believed to harbor sizeable breeding populations (Sharpe et al. 200 I). McCown\u27s Longspur habitat is shortgrass prairie with short-stature vegetation with areas of intermixed bare round (With 1994, Mollhoff 2001, Sharpe et al. 2001). Threats to the regional population include habitat conversion and fragmentation, and management practices that maintain taller vegetation (Schneider et al. 2005). In 2002 the Nebraska Prairie Partners (NPP), a cooperative partnership between the Rocky Mountain Bird Observatory (RMBO) and Nebraska Game and Parks Commission (NGPC), initiated surveys to identify the relative abundance and extent of the breeding distribution of Mountain Plover in Nebraska. One of these surveys was aimed at gaining access to private lands across the Kimball Grasslands Biologically Unique Landscape (BUL) and locating/marking Mountain Plover nests on agricultural fields. During these surveys, we routinely encountered McCown\u27s and Chestnut-collared Longspurs displaying breeding and nesting behaviors (e.g., falling leaf display). We opportunistically recorded data on McCown\u27s and Chestnut-collared Longspur nests during Mountain Plover nest marking surveys to gain knowledge of their distribution and nesting habits within Nebraska. We couple these data with data from section-based surveys conducted across western Nebraska by RMBO during the 2006 and 2007 field seasons, where both longspur species were also recorded along with general habitat data. The purpose of this paper is to provide information on nesting locations and general habitat information for both McCown\u27s and Chestnut-collared Longspurs breeding in Nebraska

Migration Chronology, Nesting Ecology, and Breeding Distribution of Mountain Plover (\u3ci\u3eCharadrius montanus\u3c/i\u3e) in Nebraska

The Mountain Plover (Charadrius montanus) is a loosely colonial (Graul 1975) upland shorebird that breeds across the xeric tablelands of the western Great Plains and shortgrass prairie ecoregion of North America (Knopf and Wunder 2006). This is a species of conservation concern throughout its range because of apparent range-wide population declines (Knopf and Wunder 2006). The U.S. Shorebird Conservation Plan (USSCP) recently classified the species as globally highly imperiled (Brown et al. 2001; USSCP 2004). Reasons for the decline of Mountain Plovers are not fully understood. Habitat destruction and the tendency of the species to nest in agricultural fields, where nests may be susceptible to destruction from agricultural practices, have been identified as possible causes (Shackford et al. 1999, Dreitz 2005, Knopf and Wunder 2006). In 2002 the Nebraska Prairie Partners (NPP), a cooperative partnership between the Rocky Mountain Bird Observatory (RMBO) and Nebraska Game and Parks Commission (NGPC), initiated a project to identify the extent of the breeding distribution and population size of Mountain Plover in Nebraska. The NPP made a concerted effort to gain access to private lands in the southwestern panhandle before initiating systematic research and monitoring activities focused on Mountain Plover ecology. Specific monitoring activities included roadside surveys, early spring visual checks in areas where plover were found in previous years, and monitoring nests in agricultural fields (nest marking) throughout May and June of most years. In addition, surveys of randomly selected 200 x 200 meter patches (patch surveys) were conducted in late April and May of the 2004–2007 field seasons. The purpose of this paper is to provide an updated, descriptive assessment of Mountain Plover in Nebraska. We base our conclusions on six years (2002–2007) of Mountain Plover monitoring data in the southwestern panhandle of Nebraska. We reviewed data collected from our monitoring activities to reassess the status of Mountain Plover in Nebraska including (1) estimated arrival dates of spring migrants and departure dates of fall migrants, (2) nesting chronology and time intervals of peak nesting activity, and (3) a general distribution of breeding Mountain Plovers in the southwest panhandle

Migration Chronology, Nesting Ecology, and Breeding Distribution of Mountain Plover (\u3ci\u3eCharadrius montanus\u3c/i\u3e) in Nebraska

The Mountain Plover (Charadrius montanus) is a loosely colonial (Graul 1975) upland shorebird that breeds across the xeric tablelands of the western Great Plains and shortgrass prairie ecoregion of North America (Knopf and Wunder 2006). This is a species of conservation concern throughout its range because of apparent range-wide population declines (Knopf and Wunder 2006). The U.S. Shorebird Conservation Plan (USSCP) recently classified the species as globally highly imperiled (Brown et al. 2001; USSCP 2004). Reasons for the decline of Mountain Plovers are not fully understood. Habitat destruction and the tendency of the species to nest in agricultural fields, where nests may be susceptible to destruction from agricultural practices, have been identified as possible causes (Shackford et al. 1999, Dreitz 2005, Knopf and Wunder 2006). In 2002 the Nebraska Prairie Partners (NPP), a cooperative partnership between the Rocky Mountain Bird Observatory (RMBO) and Nebraska Game and Parks Commission (NGPC), initiated a project to identify the extent of the breeding distribution and population size of Mountain Plover in Nebraska. The NPP made a concerted effort to gain access to private lands in the southwestern panhandle before initiating systematic research and monitoring activities focused on Mountain Plover ecology. Specific monitoring activities included roadside surveys, early spring visual checks in areas where plover were found in previous years, and monitoring nests in agricultural fields (nest marking) throughout May and June of most years. In addition, surveys of randomly selected 200 x 200 meter patches (patch surveys) were conducted in late April and May of the 2004–2007 field seasons. The purpose of this paper is to provide an updated, descriptive assessment of Mountain Plover in Nebraska. We base our conclusions on six years (2002–2007) of Mountain Plover monitoring data in the southwestern panhandle of Nebraska. We reviewed data collected from our monitoring activities to reassess the status of Mountain Plover in Nebraska including (1) estimated arrival dates of spring migrants and departure dates of fall migrants, (2) nesting chronology and time intervals of peak nesting activity, and (3) a general distribution of breeding Mountain Plovers in the southwest panhandle

Color and pigment polymorphisms of northern leopard frogs on a prairie landscape

Variation allows populations to adapt to changing conditions. As human activities continue to alter environments and evolutionary processes, it becomes increasingly important to conserve standing genetic variation. Despite technical advances in population genetics, it is still useful to have inexpensive methods of detecting and monitoring genetic variation, particularly in traits that potentially influence fitness. In the Northern Leopard Frog, Lithobates pipiens (= Rana pipiens), genetically determined color (green [dominant: G] or brown [recessive: g]) and two pigment pattern polymorphisms (Burnsi/spotless [B] or spotted [b]; Kandiyohi/mottled [K] or non-mottled[k]) are hypothesized to have adaptive benefits. We assessed spatiotemporal patterns of these polymorphisms during two time periods in one of the largest remaining grasslands in North America. The frequency of the dominant green phenotype remained consistent from the early-to-late 2000s; however, we observed Kandiyohi phenotypes more frequently during 2001–2002 compared to 2009–2010. By contrast, we observed dominant Burnsi phenotypes more frequently in the latter time period. Although not statistically significant, we observed green phenotypes more frequently in areas with less water on the landscape and in locations closer to tree cover. Burnsi phenotypes were more common in wetlands that did not dry out and Kandiyohi phenotypes were more common in wetlands with aquatic vegetation, although not significantly. No pigment polymorphism was associated with body size. We found no indication of spatial structure, suggesting ample gene flow. The correlations were generally weak, but some were consistent with hypotheses of adaptive benefits. This genetically determined phenotypic variation could be important under changing climactic conditions or if land uses change

Flow Cytometry Used to Assess Genetic Damage in Frogs from Farm Ponds

Flow cytometry (FC) is a laboratory method used to detect genetic damage induced by environmental contaminants and other stressors in animals, including amphibians. We tested FC methods on three species of ranid frogs collected from farm ponds and natural wetlands in southeastern Minnesota. We compared FC metrics for Rana clamitans between ponds with direct exposure to agricultural contaminants and reference (unexposed) ponds. Concentrations of atrazine in water from our farm ponds ranged from 0.04 to 0.55 ppb. We found that R. clamitans from exposed ponds had DNA content similar to frogs from unexposed ponds. Pond-averaged C-values (a measure of DNA content) ranged from 6.53 to 7.08 for R. pipiens (n = 13), 6.55 to 6.60 for R. clamitans (n = 40) and 6.74 for R. palustris (n = 5). Among all species, the mean sample CVs ranged from 1.91 (R. palustris) to 6.31 (R. pipiens). Deformities were observed in only 2 of 796 individuals among all species and occurred in both reference and exposed ponds. Although we did not detect evidence of DNA damage associated with agriculture in our study, we demonstrated the potential of FC for screening amphibian populations for genetic damage. Metrics from a variety of amphibian species and locations as well as laboratory studies are needed to further assess the value of FC for monitoring amphibian genetic integrity in contaminated sites

First Discovery of a Four-Egg Clutch for Mountain Plover (\u3ci\u3eCharadrius montanus\u3c/i\u3e) in Nebraska

On 27 May 2010, the first documented Mountain Plover nest in Nebraska to contain a clutch of four eggs was documented in a fallow strip of a dryland crop field in southern Kimball County. Mountain Plover typically have a clutch size of 3 eggs, though clutches with 1 and 2 eggs are observed in approximately 15% of nesting attempts (Knopf and Wunder 2006). Clutches with 4 eggs are rare and have been reported to occur in less than 1% of the population (Knopf and Wunder 2006). Five 4-egg clutches have been reported in Colorado and one in Montana (see Knopf and Wunder 2006 for details), but this was the first 4-egg clutch reported in Nebraska, and it was located after 11 years of intensive study in which a total of 598 Mountain Plover nests were located