Southwestern South Dakota Research Articles

Characterization of Modern Turtle Death Sites for Comparison with Late Eocene and Early Oligocene Turtle Sites

Taphonomic studies of extant turtles are useful for interpreting the taphonomy of fossil turtles. In order to provide modern comparators for fossil turtle sites, we have characterized two modern turtle (Chrysemys picta) deathsites; one in northwestern Nebraska and one in southwestern South Dakota. During these studies we characterized carapace position (up or down), presence or absence of non-shell elements, relative spatial position of the turtles and presence of shell disturbances (lesions). In the Trunk Butte site (Nebraska), six turtles were in carapace up position, five were in carapace down and one was not determinable. In addition, seven of those turtles contained some non-shell elements and five had indeterminable non-shell element status. At the Buffalo Gap site (South Dakota), four were carapace down, two were carapace up and three were not determinable for that character. Six of these had non-shell elements associated with them and three had no non-shell elements. The occurrence of turtles in the carapace down position suggests either the presence of medium to large scavengers able to overturn a turtle or that the turtle died while in the water and overturned while sinking. The spatial distributions of turtles in the two modern sites were also plotted and compared to that of two Whitney (Brule Formation, White River Group) and one Chadron (White River Group) site to address the hypothesis that the fossil assemblages were associated with small ponds. The results suggest that the fossil turtle sites were not the result of death events associated with small ponds, nullifying that hypothesis.

Hardwood tree decline following large carnivore loss on the Great Plains, USA

In order to investigate long-term food web linkages and trophic cascades, we conducted a retrospective analysis of large carnivores, wild and domestic ungulates, human settlement, and hardwood trees from the late 1800s to the present at Wind Cave National Park in southwestern South Dakota. We measured diameters of all cottonwood (Populus spp) and bur oak (Quercus macrocarpa) trees within a large portion of the Park to assess long-term patterns of recruitment (growth of sprouts or seedlings into tall saplings or trees). Increment cores from a subset of these trees were used to determine tree age and to develop relationships between age and diameter. Resulting age structures indicated a lack of cottonwood and bur oak recruitment for more than a century, beginning in the 1880s and continuing to the present. This is attributable to high levels of browsing, initially by livestock and subsequently by wild ungulates, in the absence of large carnivores. Conversely, we found that hardwood trees had recruited to areas protected from browsing, such as inside fenced exclosures and within a small browsing refuge. Results indicate that Great Plains ecosystems may have been profoundly altered by mounting levels of ungulate herbivory following the removal of large carnivores.

Survival of Pronghorns in Western South Dakota

Abstract: Survival and cause‐specific mortality of pronghorns (Antilocapra americana) have been well‐documented in several western states and Canadian provinces. However, no information has been collected in western South Dakota, USA, where mixed‐grass prairie habitats characterize rangelands. The objectives of our study were to determine survival and cause‐specific mortality of adult (>18 months) and yearling (6‐18 months) pronghorns and to determine monthly and summer (Jun‐Aug) survival for neonatal (<1 month of age) pronghorns in South Dakota. We radiocollared 93 adult female and 142 neonatal pronghorns on 3 areas in western South Dakota. We used bed sites from initial neonate captures to collect microhabitat information throughout Harding and Fall River counties. We measured vegetation understory and overstory height, shrub canopy, and distance to nearest concealment cover to the nearest centimeter inside 1‐m2 quadrats by collecting measurements at 15 random points within a 30‐m radius of the bed site. We documented that coyote (Canis latrans) predation was the primary cause of mortality for neonates in western South Dakota and that microhabitat characteristics at neonate bed sites differed between northwestern and southwestern South Dakota. More intensive aerial predator control may increase neonate survival in Fall River County. Management of rangelands by state and federal employees throughout western South Dakota and Wind Cave National Park that maximizes height of overstory and understory vegetation would provide neonates with adequate concealment cover for protection from predators, thereby increasing 4‐week and 12‐week postcapture survival. Our study provides South Dakota game managers with region‐specific, annual and seasonal survival rates that were previously only estimated, thus improving the accuracy of simulated pronghorn population model output. Hunting was the primary cause of mortality (26%) for adult females in Harding and Fall River counties, thereby confirming the continued use of annual harvest by South Dakota game managers as the primary management tool for maintaining pronghorn populations within statewide population management goals.

Using Weather Data to Explain Herbage Yield on Three Great Plains Plant Communities

Understanding the drivers that account for plant production allows for a better understanding of plant communities and the transitions within ecological sites and can assist managers in making informed decisions about stocking rates and timing of grazing. We compared climatic drivers of herbage production for 3 plant communities of the Clayey ecological site in southwestern South Dakota: the midgrass community dominated by western wheatgrass (Pascopyrum smithii [Rybd.] A. Love); the mixed-grass community codominated by western wheatgrass, blue grama (Bouteloua gracilis [H.B.K.] Lag. Ex Griffiths), and buffalograss (Buchloe dactyloides [Nutt.] Engelm.); and the shortgrass community dominated by blue grama and buffalograss. We used herbage yield and weather data for the period 1945–1960 collected at the South Dakota State University Range and Livestock Research Station near Cottonwood, South Dakota, to develop stepwise regression models for each plant community. Midgrass herbage production was best predicted by current-year spring (April–June) precipitation, number of calendar days until the last spring day with minimum temperature ≤ -1°C, and previous-year spring precipitation (R2 = 0.81). Mixed-grass herbage production was best predicted by current-year spring precipitation and days until the last spring freeze (R2 = 0.69). Shortgrass herbage production was best predicted by current-year spring precipitation (R2 = 0.52). Midgrass plant communities were, overall, 650 kg·ha-1 (SE = 92 kg·ha-1) more productive (P < 0.01) than mixed- or shortgrass plant communities given the same climatic inputs. Our study enables managers to make timely informed decisions regarding stocking rates and timing of grazing on this ecological site in western South Dakota. Entender los factores que participan en la producción vegetal permite una mejor comprensión de las comunidades vegetales y las transiciones dentro de los sitios ecológicos y puede ayudar a los manejadores de pastizales a tomar decisiones fundamentadas respecto a la carga animal y época de apacentamiento. Comparamos factores climáticos que influyen en la producción de forraje de 3 comunidades vegetales del sitio ecológico Arcilloso en el suroeste de South Dakota: la comunidad de zacates medios, dominada por “western wheatgrass” (Pascopyrum smithii [Rybd.] A. Love); la comunidad de zacates mixtos co-dominada por “western wheatgrass,” “blue grama” (Bouteloua gracilis [H.B.K.] Lag. Ex Griffiths), y “buffalograss” (Buchloe dactyloides [Nutt.] Engelm.); y la comunidad de zacates cortos dominada por “blue grama” y “buffalograss.” Utilizamos datos climáticos y de producción de forraje del periodo 1945–1960 colectados en la Estación Experimental de Investigación en Pastizales y Ganadería de la Universidad Estatal de South Dakota ubicada cerca de Cottonwood, South Dakota, para desarrollar modelos de regresión a pasos para cada comunidad vegetal. En la comunidad de zacates medios la mejor predicción de la producción de forraje fue obtenida con la precipitación de primavera (Abril–Junio) del año en curso, el número de días julianos hasta el último día de primavera con temperatura mínima ≤ -1°C y la precipitación en primavera del año previo (R2 = 0.81). En la comunidad de zacates mixtos, la mejor predicción de la producción de forraje se dio con la precipitación en primavera del año en curso y los días hasta la última helada en primavera (R2 = 0.69). En la comunidad de zacates cortos la mejor predicción se obtuvo con la precipitación en primavera del año en curso (R2 = 0.52). Bajo condiciones climáticas iguales, las comunidades de zacates medios, en general, fueron mas productivas (P < 0.01) que las comunidades de zacates mixtos o cortos, superandolas con 650 kg·ha-1 (SE = 92 kg·ha-1). Nuestro estudio permite a los manejadores de pastizales tomar oportunamente decisiones fundamentadas respecto a las cargas animal y épocas de apacentamiento en este sitio ecológico del oeste de South Dakota.

Regional disconformities in Turonian and Coniacian (Upper Cretaceous) strata in Colorado, Wyoming, and adjoining states biochronological evidence

Siliciclastic and calcareous sedimentary rocks of early Late Cretaceous age in the Western Interior of the United States have been assigned to, in ascending order, the Graneros Shale, Greenhorn Formation, Carlile Shale, Niobrara Formation, and their lateral equivalents (including members of the Frontier Formation and overlying formations). This sequence of formations was deposited intermittently within and near an epicontinental seaway during the Cenomanian, Turonian, and Coniacian stages of the Cretaceous. It encloses three conspicuous and widespread disconformities that reflect regional marine regressions and transgressions as well as moderate tectonism. The disconformities and associated lacunae occupy three large areas within Wyoming, Colorado, and adjoining states. In parts of that region, as in northwestern Wyoming, a lacuna can represent more than one period of erosion and more than a single disconformity. Evidence for these disconformities was obtained from about 175 collections of molluscan fossils and from sedimentological studies of outcrops and borehole logs, supplemented by previously published data. The oldest of the three disconformities, within the Frontier Formation and partial age-equivalents (including the Carlile Shale), separates Cenomanian or lower Turonian beds from middle Turonian beds in central and western Wyoming, northwestern Colorado, and adjoining areas of Montana and Utah. In parts of that region, the maximum duration of the associated lacuna is about 3 m.y. Erosion of the region in the late early Turonian was associated with a marine regression and transgression as well as mild local tectonism. The area where strata underlying the unconformity are oldest is partly overlain by the youngest of the succeeding transgressive beds. These youngest overlying beds presumably were deposited in an uplifted area where the eroded surface had a slightly higher elevation. A younger disconformity, within the Frontier Formation and lateral equivalents, separates upper Cenomanian or lower or middle Turonian strata from middle or upper Turonian strata in central and eastern Wyoming, southwestern South Dakota, western Nebraska, and central and eastern Colorado. Locally in that region, the duration of the lacuna is as much as 5 m.y. The oldest beds underlying this contact are of late Cenomanian age and are distributed in north-central and southeastern Wyoming and in north-central Colorado, where the erosional surface was affected probably by slight uplifts and by fluvial drainage systems. In that region, the oldest beds are partly overlain by the youngest (late Turonian) of the transgressive strata. The areal distribution of the younger overlying beds in central Wyoming could indicate a westward migration of marine prodelta environments during the late Turonian. At the youngest of the three disconformities, strata of middle or late Turonian ages in the Carlile Shale and lateral equivalents are overlain by upper Turonian or lower or middle Coniacian beds of the basal Niobrara Formation in Wyoming, Colorado, Nebraska, and parts of adjoining states. The maximum duration of the associated lacuna is more than 4 m.y. in northwesternmost Wyoming and northeasternmost Nebraska. Beds underlying this disconformity are oldest (early middle Turonian) in northwestern Wyoming, northeasternmost Nebraska, and possibly elsewhere in Nebraska, which apparently were areas of comparatively higher elevation and greater truncation. The underlying beds are youngest in a northeast-trending area that extends at least from eastern Utah to northeastern Wyoming. This area presumably was uplifted less than adjoining areas possibly in the late Turonian. Strata overlying this disconformity are oldest in northeastern New Mexico and much of Colorado and are youngest in northeastern Utah, northwestern and east-central Wyoming, north-central Kansas, and northeastern Nebraska, which indicates a marine transgression that progressed mainly northward. Most of the ages used for the following calculations are estimates; consequently the resulting quantitative interpretations are speculative. The duration of the lacuna between the uppermost Carlile and the basal Niobrara increased northwestward from about 0.8 m.y. in south-central Colorado to about 4.3 m.y. in northwesternmost Wyoming. It also increased northeastward from 0.8 m.y. in Colorado to about 5.1 m.y. in northeastern Nebraska. Ages of basal beds of the Niobrara decrease northwestward from about 89.3 Ma in southeastern Colorado and northeastern New Mexico to about 88.7 Ma in northwesternmost Wyoming. Apparently, the Niobrara sea transgressed northwestward about 500 mi (805 km) from southeastern Colorado to northwesternmost Wyoming in about 0.6 m.y. Ages of the basal Niobrara also decrease toward the northeast, from 89.3 Ma in southeastern Colorado to 87.6 Ma in northeasternmost Nebraska. The Niobrara sea in that region, where chronologic data are notably sparse, possibly transgressed more than 480 mi (772 km) in about 1.7 m.y.

CLIMATE EFFECTS ON FIRE REGIMES AND TREE RECRUITMENT IN BLACK HILLS PONDEROSA PINE FORESTS

Climate influences forest structure through effects on both species demography (recruitment and mortality) and disturbance regimes. Here, I compare multi-century chronologies of regional fire years and tree recruitment from ponderosa pine forests in the Black Hills of southwestern South Dakota and northeastern Wyoming to reconstructions of precipitation and global circulation indices. Regional fire years were affected by droughts and variations in both Pacific and Atlantic sea surface temperatures. Fires were synchronous with La Niñas, cool phases of the Pacific Decadal Oscillation (PDO), and warm phases of the Atlantic Multidecadal Oscillation (AMO). These quasi-periodic circulation features are associated with drought conditions over much of the western United States. The opposite pattern (El Niño, warm PDO, cool AMO) was associated with fewer fires than expected. Regional tree recruitment largely occurred during wet periods in precipitation reconstructions, with the most abundant recruitment coeval with an extended pluvial from the late 1700s to early 1800s. Widespread even-aged cohorts likely were not the result of large crown fires causing overstory mortality, but rather were caused by optimal climate conditions that contributed to synchronous regional recruitment and longer intervals between surface fires. Synchronous recruitment driven by climate is an example of the Moran effect. The presence of abundant fire-scarred trees in multi-aged stands supports a prevailing historical model for ponderosa pine forests in which recurrent surface fires affected heterogenous forest structure, although the Black Hills apparently had a greater range of fire behavior and resulting forest structure over multi-decadal time scales than ponderosa pine forests of the Southwest that burned more often.

Comparison of Detection Rates of Breeding Marsh Birds in Passive and Playback Surveys at Lacreek National Wildlife Refuge, South Dakota

Abstract We compared detection rates of passive and playback breeding bird survey techniques on elusive marsh birds--Pied-billed Grebe (Podilymbus podiceps), American Bittern (Botaurus lentiginosus), Least Bittern (Ixobrychus exilis), Virginia Rail (Rallus limicola), and Sora (Porzana carolina)--during a two-year study at Lacreek National Wildlife Refuge, in southwestern South Dakota. We conducted 151 passive point counts followed by playback-response surveys at the same points in marsh-bird habitat on the refuge. Playback surveys detected secretive water birds more frequently than our passive surveys, increasing rates for each species by factors of 2.4 to 7.0. The distance a bird was detected from a point varied with the species and the survey technique.

Disaster Response for Native Americans Complicated by History, Money

Back to table of contents Previous article Next article Community NewsFull AccessDisaster Response for Native Americans Complicated by History, MoneyEve BenderEve BenderSearch for more papers by this authorPublished Online:19 Dec 2003https://doi.org/10.1176/pn.38.24.0008aPoor disaster preparedness, a lack of resources for rebuilding, and a legacy of “collective grief” make disaster recovery especially difficult for American Indians.That was the message delivered by Marilyn Shigetani, M.A., M.P.H., to attendees at a session on the cultural aspects of disaster mental health at APA’s 2003 Institute on Psychiatric Services in Boston in October.Shigetani, an American Indian, is a Federal Emergency Management Agency (FEMA) liaison to Region IX, which encompasses California, Hawaii, and the U.S. Pacific islands.When a levee broke near the small town of Wakpala, S.D., in 1997, there were no sirens and no emergency broadcasting system to warn members of the Standing Rock Sioux tribe to evacuate ahead of the impending flood, Shigetani said. Instead, a town crier of sorts walked through the reservation telling people to evacuate.“In Indian country, there are no shelters in place when disaster strikes,” she said, “so evacuating an entire community becomes problematic.”Tribal government officials guided the displaced families to a village that was miles away. When they returned, 27 families discovered that the flood had destroyed their homes.Disaster struck again two years later. In 1999 tornadoes tore through southwestern South Dakota, causing significant damage to the Pine Ridge Indian Reservation. This time, as many as 200 Sioux families lost their homes, Shigetani said.The Pine Ridge reservation depended on money from FEMA to rebuild, she added, because “there were no funds set aside for disaster recovery.” A shortage of funds is only one of many obstacles to disaster recovery for American Indians, she said.The numerous tribulations of American Indians over the past couple of centuries make recovery from disasters such as floods and tornadoes in the present seem like an uphill battle.“We have collective grief of many treaties broken and many sad memories. We lack trust in outsiders and even other Indians. We are a race that has been separated, and we feel disempowered. Then we further victimize ourselves—we don’t need floods or tornadoes to feel like victims,” Shigetani said.In addition, admitting the need for mental health services is especially problematic for American Indians, such as members of the Standing Rock Sioux tribe. “By seeking help for the white man’s understanding of mental health problems,” she said, tribal members would believe this “shows a weakness in the community. . . .What we have done is fail each other by not meeting the needs of our people.”Shigetani dispensed the following advice to attendees about assisting American Indians in disaster recovery: One must first seek an invitation from the tribal government before one can help, she said. Introductions are important, too. Many times, she observed, people introduce themselves by stating their names and the agency they represent.“Now you are an institution—not a person—coming to help,” she observed. “We’ve had some experiences with institutions, and there are some issues there. . . . To us, it’s not who you represent that is important, but who you are.”In addition, American Indians want to know how committed outsiders are to helping them cope with disaster. “How long are you going to be around?” Shigetani asked. “Are you going to assist us through the transition to recovery, or are you going to spend a couple of weeks and then get out of town?”She advised attendees that they should be “committed for the long haul,” or at least work with staff from local mental health or disaster-relief organizations or both to ensure that their efforts are carried out. ▪ ISSUES NewArchived

Marine Cretaceous-Tertiary boundary section in southwestern South Dakota: Comment and Reply

In a similar vein to what Dana posited for Hall's geosynclinal theory for the origin of mountain belts—that it presented “a theory for the origin of mountains with the origin of mountains left out” (p. 55, King, 1977)—[Terry et al. (2001)][1] promote the presence of a Cretaceous-Tertiary (K-

Optimizing habitat location for black-tailed prairie dogs in southwestern South Dakota

A spatial optimization model was formulated and used to maximize black-tailed prairie dog populations in the Badlands National Park and the Buffalo Gap National Grassland in South Dakota. The choice variables involved the strategic placement of limited additional protected habitat. Population dynamics were captured in formulations that reflected exponential population growth combined with the recalcitrant dispersal behavior of this social mammal that is important to many other species. The model results are compared to a previous paper which modeled the black-footed ferret, an aggressive disperser that is dependent upon prairie dogs for food and shelter.

Marine Cretaceous-Tertiary boundary section in southwestern South Dakota

A distinctive zone of disrupted strata, which we interpret as a distal manifestation of the end-Cretaceous Chicxulub impact event, occurs over 300 km 2 in southwestern South Dakota. This disrupted zone is within the Fox Hills Formation, ranges from 0.5 to 5 m in thickness, and contains large-scale slump-roll structures, clastic dikes, flame structures, and massive, homogenized beds. The zone is ∼0.5 m above a belemnite fauna Sr dated as 67.6 ± 0.5 Ma, contains scaphitid ammonites characteristic of the Jeletzkytes nebrascensis ammonite zone of the Fox Hills Formation, and is capped by a 0.5–4-cm-thick brownish-black mudstone that contains spherules. Pollen of the late Maastrichtian Wodehouseia spinata palynostratigraphic zone occurs immediately above and below the disrupted zone. The disrupted zone is overlain by an additional 25 m of marine Fox Hills Formation. These stratigraphic relationships suggest that the upper part of the Fox Hills Formation in this part of South Dakota is Paleocene; that the Western Interior Seaway was locally present well into the Paleocene; and that scaphitid ammonites may range the Cretaceous-Tertiary (K-T) boundary.

On the Rez by Ian Frazier

4 3 2 WAL 3 5 .4 WINTER 2 0 01 narrative, Black Hawk’s “autobiography,” and guidebooks and artwork in the U.S. Capitol. In her strongest chapters, Scheckel reveals not only the inter­ play of popular and official rhetoric about Indians, but the interplay of gender and race in the construction of national identity. For example, she offers a mas­ terful reading ofhow guidebooks, produced for the U.S. Capitol visitor between the 18.30s and 1860s, enlisted citizens in a larger drama of U.S. history through its representation of Capitol commemorative artworks of American Indians which “made the political exclusion of Indians seem natural and necessary” (129). In this nuanced analysis, Scheckel links (although does not fully tease out) the “gendered construction of citizenry” enacted in this artwork with the construction of maternal and sexualized roles for Euro-American and Native American women in the other national origin stories covered in the book (139). When the West was East, U.S. legal and cultural texts staged efforts to pin down shifting and unstable boundaries of national identity. Though focused on the early nation, The Insistence of the Indian directs us toward the continued persistence of the “Indian” in U.S. popular culture and policy debates, thus underscoring how American Indians still “frame the meaning of the nation” (151). As such, Scheckel’s sharp reading of U.S. culture’s foundational ambiva­ lence toward American Indians holds lamentably and equally true for today: “Americans were anxious to embrace them as relics of the national history they longed for—and the present—where they could be located neither entirely within nor outside of American society” (95). O n the Rez• By Ian Frazier. N ew York: Farrar, Strau s and G iroux, 2000. 311 pages, $25.00. Reviewed by N ath an iel Lew is St. M ich ael’s College, C olchester, Verm ont Ian Frazier’s new book, On the Rez, is in many ways a response to his 1989 masterpiece, Great Plains. Great Plains celebrated the West as a place to be imagined; like Fitzgerald’s Nick Carraway “brooding on the old unknown world,” Frazier played the past against the present, lamenting lost opportuni­ ties but celebrating, through surprising literary reaches, the breathtaking joy of American mythology. It remains a cheerfully extravagant book (“Away to the Great Plains . . . now mostly plowed under!” [3]), brilliantly delivered; but it is also, in Frazier’s own reflection, “pretty romantic.” He later “realized that there was a very different way of looking at this part of the world. The idea of the pristine continent is a complete fantasy, and yet we keep playing it over and over again.” On the Rez is his attempt to look at the West “from another direc­ tion,” and it is indeed a much darker, quieter book, filled with doubt and uneasiness (from Atlantic Monthly [Dec. 1999]: 6). On the Rez opens with Frazier’s distinctively direct, calm voice: “This book is about Indians, particularly the Oglala Sioux who live on the Pine Ridge BOOK REVIEWS Reservation in southwestern South Dakota, in the plains and badlands in the middle of the United States” (3). For Frazier, Indian history and culture are cen­ tral in every way to understanding America itself; the fact that he is an outsider to the land and community at Pine Ridge saddens him but also gives him the opportunity to reconsider his own sense of self and country. He greatly admires what he finds in his reading about Lakota culture and in his visits to the reser­ vation: an egalitarian, independent community living with a “self-possessed sense of freedom” that can produce genuine heroes (5). And although he has no interest in playing Indian, he admits to being a “wannabe” (4). (He candidly asks, “[W]hat’s wrong with wanting to be something, anyway?” [4].) Countering such idealized (indeed, romantic) descriptions is the predictably depressing depiction of reservation alcoholism, violence, poverty, loss, and despair. Frazier acknowledges that there is often a disparity between the idea and the fact of Pine Ridge. “I know that the hopeful, big-sky feeling with which we often invest Western landscapes is at odds...

The Pine Ridge-Mayo National Aeronautics and Space Administration Telemedicine Project: Program Activities and Participant Reactions

To determine the response of participants to the Pine Ridge-Mayo National Aeronautics and Space Administration telemedicine project. We describe a 3-month demonstration project of medical education and clinical consultations conducted by means of satellite transmission. Postparticipation questionnaires and a postproject survey were used to assess the success of the activity. Patients and employees at the Pine Ridge Indian Health Service Hospital in southwestern South Dakota and employees at Mayo Clinic Rochester participated in a telemedicine project, after which they completed exit surveys and a postproject questionnaire to ascertain the acceptability of this mode of health care. Almost all Pine Ridge and Mayo Clinic participants viewed the project as beneficial. The educational sessions received favorable evaluations, and almost two-thirds of the patients who completed evaluations thought the consultation had contributed to their medical care. More than 90% of the respondents from Pine Ridge and more than 85% of the respondents from Mayo Clinic Rochester said that they would recommend participation in this project to others. More than 90% of respondents from Pine Ridge and 80% of Mayo respondents agreed with the statement that the project should continue. These data suggest that a program of clinical consultation services, professional education, and patient education available by telemedicine might be viewed as beneficial.

Carrying Capacity of Age-Specific Habitat Zones within Black-Tailed Prairie Dog Colonies: A Baseline Preceding Black-Footed Ferret Reintroduction

Plant-animal interactions vary strongly between habitat zones characterized by the duration of colonization (age-specific) within a black-tailed prairie dog (Cynomys ludovicianus) town (Cincotta et al. 1984). These interactions largely determine vegetation composition, diet composition and quality, and population demographics of habitat zones. The ecology of the black-tailed prairie dog in Badlands National Park (BNP) has been described by Cincotta et al. (1984) and Sharps and Uresk (1990). Yet, there is still uncertainty about the plant-animal relationships which underpin prairie dog carrying capacity in different habitat zones. Understanding the variability in the ecology of black-tailed prairie dogs between habitat zones of mature towns is fundamental to successful reintroduction of the black-footed ferret (Mustela nigripes) into southwestern South Dakota. The predator-prey relationship between black-tailed prairie dogs and black-footed ferrets is dependent in large part upon density of prey. Additionally, an understanding of black-tailed prairie dog population and foraging ecology will be a required contribution by BNP to the development of a multiple large and small herbivore carrying capacity management model. For the purposes of this proposal, carrying capacity is defined as an estimate of densities of prairie dogs supportable at different levels of forage availability and quality (Hobbs and Swift 1985). Of the habitat zones in an aging prairie dog town, the old-town centers (OTC) and young-town edge (YTE) zones offer the most widely differing habitat characterizations (Cincotta et al. 1984), and should provide the most interesting test of the effect of habitat quality on prairie dog carrying capacity. The objectives of this research are 1) To estimate the carrying capacity of black-tailed prairie dogs in different habitat zones of an aging town, and 2) To understand how vegetation characteristics and prairie dog feeding habits influence the number of black­tailed prairie dogs which can be supported in different habitat zones.

Variations in Surface‐Layer Color, Texture, pH, and Phosphorus Content Across Prairie Dog Mounds

AbstractSpatial variations of soil surface color, texture, pH, and phosphorus content were studied so the effects of relict and modern prairie dog (Cynomys ludovicianus) pedoturbation on soil surface properties will be more predictable in southwestern South Dakota. When first formed, prairie dog mounds are made of surface soil. In time, lower‐layer materials are added to the surface. The overall textural variation usually increases with pedoturbation because the original surface layer has a different texture than the subsoil. The mound pH is usually greater than the adjacent soil because calcareous subsoil is deposited in the mound. With time, the mound pH decreases as carbonate leaches and the color becomes darker as organic matter accumulates. The color hue gradually changes to a 10YR if the subsoil was not originally a 10YR hue. Fecal and skeletal phosphorus are deposited in and on the mound to increase areal variation in phosphorus content as a mound continues to be used.

Evaluation of Potential Herbivore Mediation of Plant Water Status in a North American Mixed-Grass Prairie

Xylem water potentials (ip) were monitored diurnally from June through August 1981 to ascertain the water status of plants of four species growing on a heavily grazed prairie dog (Cynomys ludovicianus) colony and an adjacent lightly grazed uncolonized site in southwestern South Dakota. Highest p values were observed in June and August after periods of relatively high precipitation. Lowest values occurred in July when soil moisture had been depleted. However, there were no large differences in V of grasses (Agropyron smithii, Andropogon gerardi, and A. scoparius) growing on and off the prairie dog colony, even though root biomass of plants on the colony was substantially lower. While midday leaf conductance was comparable for A. smithii tillers on and off the colony, conductance values for A. gerardi and A. scoparius tillers were generally higher (17 to 60%) on the heavily grazed site. Artemisia frigida plants had slightly higher Vp on the prairie dog town during periods of moderate or high water stress. Soil moisture content was slightly but significantly (P _ 0.05) higher on the heavily grazed prairie dog town, even though afternoon soil temperatures at the 15-cm depth averaged 2.7°C higher.

Depositional Environment of Leo Sands, Middle Minnelusa Formation, Niobrara County, Wyoming: ABSTRACT

The Upper Pennsylvanian middle Minnelusa Formation Leo Sands in the north half of Niobrara County, Wyoming, and southwestern South Dakota, may have been deposited in a nearshore eolian sabkha environment. Cores reveal sedimentary features which support this hypothesis, such as deflation lags, avalanche-produced strata, probable interdune deposits, and nodular anhydrites. The Leo Sands have proven to be excellent reservoir rocks. Associated anhydrites provide the seal for hydrocarbons which may have been generated from organic-rich interdunal shales. End_of_Article - Last_Page 1349------------

Reduction of Horse and Deer Flies on the Cottonwood Range and Livestock Experiment Station as a Result of Grazing12

Horse fly and deer fly populations were sampled on an experiment station in southwestern South Dakota during the summer of 1977, 1978, and 1980. Tabanus similis Macquart and Chrysops aestuans van der Wulp were the most common species collected by blackball and sticky-drum traps. T. similis adults were commonly observed as a pest of beef cattle from June to early August, whereas C. aestuans was attracted more commonly to humans during this period. Fly populations were lower in 1980 when compared with numbers found in previous years. It is suggested that weather conditions and grazing by beef cattle in 1979 reduced the amount of vegetation on which flies could oviposit, resulting in fewer adults caught dunng the 1980 season. C. sequax Williston and C. carbonarius Walker also were attracted to humans, whereas collections of T. marginalis F., T. orbicallus Philip, and Silvius pollinosus Williston represent new records for South Dakota.

Food Habits of Bison at Wind Cave National Park

Wind Cave National Park (WCNP) in southwestern South Dakota represents a vestige of the prairie ecosystem. American bison (Bison bison) are the most numerous ungulates in the Park and the largest herbivore. Thus bison have potential for considerable impact on the rangelands. Relatively few studies (Meagher 1973, Peden et al. 1974, Peden 1976, Reynolds 1978) were conducted on bison food habits. None was conducted on mid-grass prairies typical of WCNP. Dietary information is important for determining the value of the range to bison as well as management of bison in relation to other herbivores. The objectives of this study are to determine seasonal food habits of bison, key forage species, and how the bison interact with other major herbivores in range use.

Two New North American Miocene Salamandrids

Palaeotaricha van Frank apparently differs from Taricha primarily in the possession of higher neural spines provided with a dermal cap. Generic status is probably not warranted on this basis, but Palaeotaricha does constitute a recognizable subgenus of Taricha existing at least from the upper Oligocene to the lower Miocene. It may be directly ancestral to the nominate subgenus. Taricha (Palaeotaricha) miocenica, sp. nov., is described herein from the lower Miocene of Montana, as is also a new species of Notophthalmus, N. crassus, from the middle Miocene of southwestern South Dakota.