Shortgrass Prairie Research Articles

Influence of vegetation structure on the small mammal community in a shortgrass prairie ecosystem

The structure of vegetation, and how this structure varies across a landscape, is crucial to understanding the distribution of wildlife species. Between 2002 and 2004, we sampled small mammal communities and measured vegetation structure at 185 locations across a range of disturbance regimes in a shortgrass prairie ecosystem in southeastern Colorado, USA. At each sampling location, the local disturbance regime was some combination of varying intensity of livestock grazing, military training activity, and fire. Vegetation structural characteristics measured included percent bare ground, basal cover, litter, shrub density, and mean grass and shrub height. Rodent communities were described by richness, diversity, total and per capita biomass, and species abundances. Northern grasshopper mice (Onychomys leucogaster), Ord's kangaroo rats (Dipodomys ordii), silky pocket mice (Perognathus flavus), western harvest mice (Reithrodontomys megalotis), white-footed mice (Peromyscus leucopus), southern plains wood rats (Neotoma micropus), thirteen-lined ground squirrels (Spermophilus tridecemlineatus), deer mice (Peromyscus maniculatus), and spotted ground squirrels (Spermophilus spilosoma) accounted for >99 % of all captures. Canonical correlation analysis was used to assess the relationship between small mammals and vegetation structure. The first two canonical variates explained over 50 % of the variation in vegetation structure and were related to the ratio of bare ground to basal coverage and litter accumulation. Rodent community indices were most strongly related to litter accumulation and shrub density, though the models had low explanatory power. Our results agreed with published findings regarding microhabitat associations and indicated small mammal communities benefited from a system of interacting disturbances and the resulting landscape mosaic.

Effects of a New Herbicide (Aminocyclopyrachlor) on Buffalograss and Forbs in Shortgrass Prairie

Herbicides used to control many forb species in pastures may injure desirable native grass species. Buffalograss, a major component of shortgrass rangeland, often is injured by some growth regulator herbicides, such as 2,4-D and dicamba. Aminocyclopyrachlor (formerly known as DPX-MAT28 and herein termed ACPCR), a new synthetic auxin herbicide chemistry for control of broadleaf weeds, was investigated for injury to buffalograss and control of forbs in shortgrass prairie at varying rates of application. In the season of application, ACPCR at rates of 140 g ai ha−1or less caused buffalograss injury that was either negligible or short-lived, and visual estimates of grass injury were 8% or less at the end of the growing season. At ACPCR rates of 280 g ha−1, more injury was evident at 3 wk after treatment (WAT) than at the end of the season if adequate precipitation was available for new leaf growth. When precipitation was lacking, evidence of injury persisted through to the end of the season when treated at the greatest rate of ACPCR. Buffalograss injury was mainly in the form of browned leaf tips, but total buffalograss dry matter yield was not different between any treatments in either year. The year after treatment, no buffalograss injury was evident from any of the herbicide rates. Final forb control was 97% or greater each year for ACPCR at the 140 and 280 g ha−1rates. In this experiment, rates as low as ACPCR at 140 g ha−1provided excellent forb control and maintained buffalograss productivity.

Broad-sense Heritability Estimates of Turfgrass Performance Characteristics in Native Prairie Junegrass Germplasm

Prairie junegrass [Koeleria macrantha (Ledeb.) Shultes] is a perennial, short-grass prairie species distributed throughout the Northern Hemisphere that is being evaluated for use as a low-input turf. In June 2007, 300 genotypes representing collection locations derived from Colorado, Nebraska, and Minnesota germplasm were grown and evaluated 3 years for turfgrass performance characteristics in a randomized complete block design with five clonal replications at two locations (St. Paul, MN, and Becker, MN). After establishment, plots received no supplemental irrigation or fertility and were mowed weekly to a height of 6.4 cm. Broad-sense heritability estimates were calculated on a clonal mean (Hc) and single-plant (Hsp) basis for turf quality (Hc = 0.62, Hsp = 0.13), crown density (Hc = 0.55, Hsp = 0.09), mowing quality (Hc = 0.59, Hsp = 0.09), and genetic color (Hc = 0.45, Hsp = 0.06). The heritability estimates indicate that selection for these traits should result in significant gains in germplasm improvement. Differences were observed in the means and variances among clones, collection locations, and/or collection regions for many of the traits evaluated including rust severity (Puccinia spp.), spring green-up, plant height, lateral spread, vertical regrowth, and flowering traits. The positive correlations among some of these traits and those with moderate heritability estimates should allow for multi-trait selection in cultivar development.

Microsatellite primers in Oenothera harringtonii (Onagraceae), an annual endemic to the shortgrass prairie of Colorado

Microsatellite markers were developed in the annual herb, Oenothera harringtonii, to investigate patterns of genetic diversity, gene flow, and parentage within and among populations of this Colorado endemic. Ten polymorphic loci were identified in O. harringtonii and tested in four populations sampled across the range of the species. These loci contained trinucleotide repeats with 7-29 alleles per locus. Nine of the 10 loci also amplified in O. caespitosa subsp. macroglottis, O. caespitosa subsp. marginata, and O. caespitosa subsp. navajoensis. In addition, we optimized three markers developed for O. biennis and provide reports of their effectiveness in all four taxa. These results indicate the utility of these markers in O. harringtonii for future studies of genetic structure, gene flow, and parentage as well as their applicability in other members of the O. caespitosa species complex.

Traditions of the Osage: Stories Collected and Translated by Francis La Flesche , and: The People Who Stayed: Southeastern Indian Writing after Removal (review)

Reviewed by: Traditions of the Osage: Stories Collected and Translated by Francis La Flesche, and: The People Who Stayed: Southeastern Indian Writing after Removal Matt Low Traditions of the Osage: Stories Collected and Translated by Francis La Flesche. Edited by Garrick Bailey. Albuquerque: University of New Mexico Press, 2010. 192 pages, $29.95. The People Who Stayed: Southeastern Indian Writing after Removal. Edited by Geary Hobson, Janet McAdams, and Kathryn Walkiewicz. Norman: University of Oklahoma Press, 2010. 404 pages, $24.95. Washington Irving is mentioned briefly in the introduction to The People Who Stayed: Southeastern Indian Writing after Removal, when the editors cite his A Tour on the Prairies (1835) as an example of a work in which “an accomplished craftsman took pains to create Indians as people instead of types” (10). While some might take issue with the accuracy of this statement, it is nonetheless fitting that Irving’s A Tour on the Prairies is alluded to here, since that work actually serves as an interesting bridge between The People Who Stayed and the second text in question in this review, Traditions of the Osage: Stories Collected and Translated by Francis La Flesche. A Tour on the Prairies was written after Irving’s brief excursion to the mixed- and shortgrass prairies of Kansas and Oklahoma—the heart of what was then Osage territory—in the fall of 1832. Indeed, the Osage are the primary Native culture with which Irving interacts while on his “tour.” Irving’s work is intimately tied to the post-Removal literature accumulated in the pages of The People Who Stayed as well, as the person leading Irving’s expedition was none other than Henry Leavitt Ellsworth, Commissioner on Indian Affairs and point man for Andrew Jackson’s early efforts to relocate the Native communities of the Southeast to “Indian Territory” in present-day Oklahoma. More than just a bit of trivia from nineteenth-century American literature, the link that Irving allows between these two recent collections of traditional and contemporary Native literature speaks to the interconnectedness of their concerns, in spite of the geographical and cultural gaps separating them: namely, the desire to overturn dominant narratives of western settlement and progress, of which Irving can be seen as a standard-bearer, by giving a voice to those formerly silenced by the presumption that Native cultures throughout North America willingly succumbed to the pressures of Euro-American civilization. Compared to the indigenous cultures with which they cohabited the prairies and plains of the North American midcontinent—such as the Sioux, Cheyenne, Pawnee, and even Kiowa—the Osage are not as prominently discussed in the history and literature of the region. Traditions of the Osage thus serves as a correction to the absence of Osage life and culture in contemporary analyses of the region and its people, in particular critiques of Euro-American settlement [End Page 457] and removal. In the first two chapters, Garrick Bailey offers the reader a concise history of the Osage following contact with the French in the mid-eighteenth century. Unsurprisingly, most of this narrative involves the Osage losing traditional home grounds through a series of treaties with and incursions by the French, the Spanish, and eventually the Americans, perhaps most prominently in the era of Jacksonian Removal that serves as the backdrop for The People Who Stayed. However, Bailey gives ample space to other components of Osage culture and society, contextualizing the traditional stories included by elaborating upon religious beliefs, tribal organization, and the day-to-day life of Osage men, women, and children. Bailey organizes the stories themselves into three different categories: sacred teachings, folk stories, and animal stories. Most of these are what one would expect in such a collection; the sacred teachings, for example, include numerous stories describing Osage cosmogony, the implementation of religious customs and practices, and moral prescriptions by which to live. Likewise, the folk stories recount legends of prominent Osage events and people, while the few animal stories included tend toward the allegorical. The standout of the collection is a folk story titled “The Woman War Leader,” which tells of a widow who mourns the loss of her husband before organizing a war party of...

Weather effects on avian breeding performance and implications of climate change

The influence of recent climate change on the world's biota has manifested broadly, resulting in latitudinal range shifts, advancing dates of arrival of migrants and onset of breeding, and altered community relationships. Climate change elevates conservation concerns worldwide because it will likely exacerbate a broad range of identified threats to animal populations. In the past few decades, grassland birds have declined faster than other North American avifauna, largely due to habitat threats such as the intensification of agriculture. We examine the effects of local climatic variations on the breeding performance of a bird endemic to the shortgrass prairie, the Lark Bunting (Calamospiza melanocorys) and discuss the implications of our findings relative to future climate predictions. Clutch size, nest survival, and productivity all positively covaried with seasonal precipitation; yet relatively intense daily precipitation events temporarily depressed daily survival of nests. Nest survival was positively related to average temperatures during the breeding season. Declining summer precipitation may reduce the likelihood that Lark Buntings can maintain stable breeding populations in eastern Colorado although average temperature increases of up to 3 degrees C (within the range of this study) may ameliorate declines in survival expected with drier conditions. Historic climate variability in the Great Plains selects for a degree of vagility and opportunism rather than strong site fidelity and specific adaptation to local environments. These traits may lead to northerly shifts in distribution if climatic and habitat conditions become less favorable in the drying southern regions of the Great Plains. Distributional shifts in Lark Buntings could be constrained by future changes in land use, agricultural practices, or vegetative communities that result in further loss of shortgrass prairie habitats.

Smoke Water and Heat Shock Influence Germination of Shortgrass Prairie Species

Smoke or heat from fire can act as a cue that affects seed germination. We examined germination responses of 10 plant species (six forbs, two shrubs, two grasses) native to the southern High Plains in the United States, to smoke, heat, and their interaction in a laboratory experiment. Smoke treatments were applied by soaking seeds in 1∶5, 1∶10, or 1∶100 (v/v) Regen 2000® smoke solution for 20 h. Heat treatments were applied by placing seeds in an oven at 50°C or 80°C for 5 min. Nine species responded to smoke, heat, or both. Results showed that smoke can enhance, inhibit, or not affect seed germination. Germination capacities of Gutierrezia sarothrae (Pursh) Britton & Rusby and Astragalus crassicarpus Nutt. were promoted by 1∶5 and 1∶100 dilutions of smoke water, respectively; Coreopsis tinctoria Nutt., G. sarothrae, Salvia reflexa Hornem., Digitaria ciliaris (Retz.) Koeler, and Panicum virgatum L. were inhibited by high and/or moderate concentrations of smoke water either in germination percentage or in mean germination time. Germination percentage of Solanum elaeagnifolium Cav. increased following an 80°C heat treatment. Interaction effects between smoke and heat on germination also were detected. Smoke and heat treatments might be useful as management tools for promoting or suppressing specific target species of shortgrass prairie communities in future habitat management. El ahumado o calor del fuego puede actúa como agente que afecta la germinación de semillas. En un experimento de laboratorio, examinamos la respuesta de diez especies nativas (seis hierbas, dos arbustos, y dos pastos) de las Planicies del Sur de los Estados Unidos al ahumado, calor y las interacciones. En los tratamientos de ahumado se remojaron semillas con la solución de ahumado Regen 2000® en 1∶5, 1∶10, o 1∶100 (v/v) por 20 horas. Los tratamientos de calor se aplicaron poniendo semillas en un horno a 50°C o 80°C por 5 minutos. Nueve especies respondieron al ahumado, calor, o ambos. Los resultados mostraron que el ahumado podría mejorar, inhibir o no afectar la germinación. Las capacidades de germinación de la Gutierrezia sarothrae (Pursh) Britton & Rusby y Astragalus crassicarpus Nutt. fueron estimuladas por la dilución de 1∶5 y 1∶100 ahumador agua, respectivamente; Coreopsis tinctoria Nutt., G. sarothrae, Salvia reflexa Hornem., Digitaria ciliaris (Retz.) Koeler, y Panicum virgatum L. fueron inhibidas por alto y/o moderada concentración de ahumador agua en ambos porcetaje de germinación o en tiempo promedio de germinación. El porcentaje de germinación de Solanum elaeagnifolium Cav. aaumento después del tratamiento de calor a 80°C. Se detectaron efectos de interacciones entre ahumado y calor en la germinación. Los tratamiento de ahumado y calor podrían ser útiles como herramientas de manejo para promover o suprimir especies claves especificas de las comnidades de las praderas de pastos cortos en futuros manejos de hábitat.

Comparison of bird and mammal communities on black-tailed prairie dog (Cynomys ludovicianus) colonies and uncolonized shortgrass prairie in New Mexico

Black-tailed prairie dogs (BTPD; Cynomys ludovicianus) have often been labeled as keystone species because of their ability to strongly influence grassland ecosystems. I used line-transect surveys and distance sampling to compare breeding bird and mammal communities on shortgrass prairie occupied by BTPD colonies versus similar uncolonized habitat in New Mexico, and to identify species that were either strongly associated with, or that avoided, BTPD colonies. Overall, I detected 32 bird and 8 mammal species during three years. Mountain plover (Charadrius montanus), ferruginous hawk (Buteo regalis), burrowing owl (Athene cunicularia), curve-billed thrasher (Toxostoma curvirostre), desert cottontail (Sylvilagus audubonii), and American badger (Taxidea taxus) were more abundant on, or at least strongly associated with, colonies, while long-billed curlew (Numenius americanus), horned lark (Eremophila alpestris), vesper sparrow (Poecetes gramineus), lark sparrow (Chondestes grammacus), Cassin's sparrow (Aimophila cassinii), and western meadowlark (Sturnella neglecta) were more abundant on, or strongly associated with, uncolonized prairie. Observed responses of several species differed from other studies suggesting that a species' response to BTPD activities may vary by location, grassland type, or season. Although BTPDs negatively impacted a suite of grassland bird species, biodiversity is maximized in this landscape by maintaining a mixture of colonized and uncolonized habitats.

Influence of land-use and conservation programs on wetland plant communities of the semiarid United States Great Plains

Depressional wetlands are predominant surface hydrological features providing critical societal ecosystem services in the semiarid United States High Plains. Critical wetland properties may be threatened because this 30 million ha short-grass prairie largely was converted from grassland to cropland. Further, the United States Department of Agriculture enrolled marginal cropland into the Conservation Reserve Program (CRP). CRP reduces topsoil erosion by planting permanent cover on croplands. In the High Plains, introduced tall-grasses primarily were planted in CRP, possibly reducing precipitation runoff, an important hydroperiod driver in wetlands. We assessed land-use influence on important wetland processes (wetland area, inundation, and plant composition) in 261 depressional wetlands called playas (87 each in native grassland, CRP, and cropland). Surveys spanned six states within three High Plains sub-regions (southern, central and northern). Playas averaged 8ha in cropland and 16ha in other land-uses. Plant composition in grassland playas was predominately native perennials, and upland plant cover equaled wetland plant cover. Cropland playas had fewer species/ha, generally more annuals than perennials and 80% greater exposed ground than other land-uses. CRP playas had 400% greater cover of introduced species (mostly upland perennial tall-grasses), which possibly inhibited catchment runoff, as CRP playas were inundated 56% less often than other land-uses. Therefore, tall grasses should not be planted in short-grass prairie CRP catchments, as they alter inundation frequency and vegetation communities in embedded wetlands. Conservation programs containing provisions to protect playas, including planting common native species and using grass buffers to control erosion into wetlands, should be promoted.

Incorporating Biodiversity Into Rangeland Health: Plant Species Richness and Diversity in Great Plains Grasslands

Indicators of rangeland health generally do not include a measure of biodiversity. Increasing attention to maintaining biodiversity in rangelands suggests that this omission should be reconsidered, and plant species richness and diversity are two metrics that may be useful and appropriate. Ideally, their response to a variety of anthropogenic and natural drivers in the ecosystem of interest would be clearly understood, thereby providing a means to diagnose the cause of decline in an ecosystem. Conceptual ecological models based on ecological principles and hypotheses provide a framework for this understanding, but these models must be supported by empirical evidence if they are to be used for decision making. To that end, we synthesize results from published studies regarding the responses of plant species richness and diversity to drivers that are of management concern in Great Plains grasslands, one of North America's most imperiled ecosystems. In the published literature, moderate grazing generally has a positive effect on these metrics in tallgrass prairie and a neutral to negative effect in shortgrass prairie. The largest published effects on richness and diversity were caused by moderate grazing in tallgrass prairies and nitrogen fertilization in shortgrass prairies. Although weather is often cited as the reason for considerable annual fluctuations in richness and diversity, little information about the responses of these metrics to weather is available. Responses of the two metrics often diverged, reflecting differences in their sensitivity to different types of changes in the plant community. Although sufficient information has not yet been published for these metrics to meet all the criteria of a good indicator in Great Plains Grasslands, augmenting current methods of evaluating rangeland health with a measure of plant species richness would reduce these shortcomings and provide information critical to managing for biodiversity. Los indicadores de la salud de los pastizales generalmente no incluyen una medida de la biodiversidad. El aumento en la atención de mantener la biodiversidad en los pastizales sugiere que esta omisión sea reconsiderada. La riqueza y la diversidad de las especies de plantas son dos parámetros que pueden ser muy útiles y apropiados. Idealmente, su respuesta a una variedad de factores antropogénicos y naturales en el ecosistema de interés se podría entender claramente, proporcionando los medios para diagnosticar la causa del detrimento del ecosistema. Los modelos ecológicos conceptuales basados en principios e hipótesis ecológicos proporcionan un marco para esta comprensión, pero estos modelos deben ser apoyados por evidencias empíricas si van a ser utilizados para la toma de decisiones. De tal manera, resumimos los resultados de estudios publicados con respecto a las respuestas de la riqueza y de la diversidad de las especies de plantas y los factores que son de preocupación a los manejadores de los pastizales de las grandes planicies, uno de los ecosistemas más amenazado de Norte América. En la literatura publicada, el pastoreo moderado generalmente tiene un efecto positivo en estos parámetros en los pastizales altos y un efecto neutro o negativo en los pastizales cortos. La mayoría de las publicaciones sobre la riqueza y diversidad de los pastizales fueron causadas por el pastoreo moderado en los pastizales altos y la fertilización de nitrógeno en los pastizales cortos. Aunque, el clima se cita frecuentemente como la razón de las fluctuaciones anuales considerables en la riqueza y la diversidad, poca información sobre las respuestas de estos parámetros al clima está disponible. Las respuestas de los dos parámetros difirieron a menudo, reflejando discrepancias en su sensibilidad a diversos tipos de cambios en la comunidad de la planta. Aunque suficiente información todavía no se ha publicado para que estos dos parámetros cubran todos los criterios de un buen indicador de los pastizales de las grandes planicies, el incluir en los métodos actuales de evaluación de la salud de los pastizales, una medida de riqueza de las especies de las plantas reduciría estos defectos y proporcionaría la información crítica para el manejo de la biodiversidad.

On the Cover – Buffalo Grass

Buffalo grass, Buchloë dactyloides Engelm., is a North American native short-grass, sod-forming, shade-intolerant perennial. The genus name comes from the Greek rendering of the common name: boubalos, buffalo and chloë, grass (synonymous with Bulbilis dactyloides Raf.). 1 Hitchcock A.S. Manual of the Grasses of the United States. in: 2nd Ed. Dover Publications Inc, New York1971: 545-546 Google Scholar When unmixed with other grasses, it forms a dense soft, grayish-green turf, 5–10 cm thick. It is dominant over large areas of the upland Great Plains referred to as “short-grass prairie.” 1 Hitchcock A.S. Manual of the Grasses of the United States. in: 2nd Ed. Dover Publications Inc, New York1971: 545-546 Google Scholar , 2 Lewis W.H. Vinay P. Zenger V.E. Airborne and Allergenic Pollen of North America. in: Johns Hopkins University Press, Baltimore1983: 105-121 Google Scholar , 3 Gould F.W. Common Texas Grasses: An Illustrated Guide. in: Texas A&M University Press, College Station, TX1978: 69-72 Google Scholar Its range is from southern Saskatchewan and Manitoba, through Montana to Minnesota, western Iowa, from Arizona to western Louisiana, and through much of northern Mexico. 1 Hitchcock A.S. Manual of the Grasses of the United States. in: 2nd Ed. Dover Publications Inc, New York1971: 545-546 Google Scholar , 2 Lewis W.H. Vinay P. Zenger V.E. Airborne and Allergenic Pollen of North America. in: Johns Hopkins University Press, Baltimore1983: 105-121 Google Scholar , 4 Barkworth M.E. Anderton L.K. Capels K.M. Long S. Piep M.B. Manual of Grasses for North America. Utah State University Press, Logan, UT2007 Google Scholar It is best adapted to loamy clay soils with runoff during rainy seasons. It is very hardy and persists with long summer droughts as well as periods of flooding. 5 Haddock M.J. Wildflowers & Grasses of Kansas. University Press of Kansas, Lawrence, KS2005 Google Scholar Buffalo grass is one of the most important grazing grasses, providing nutritious feed even during the winter. 1 Hitchcock A.S. Manual of the Grasses of the United States. in: 2nd Ed. Dover Publications Inc, New York1971: 545-546 Google Scholar , 3 Gould F.W. Common Texas Grasses: An Illustrated Guide. in: Texas A&M University Press, College Station, TX1978: 69-72 Google Scholar , 4 Barkworth M.E. Anderton L.K. Capels K.M. Long S. Piep M.B. Manual of Grasses for North America. Utah State University Press, Logan, UT2007 Google Scholar It is good grazing for livestock and fair for wildlife. It provides good cover for exposed dry banks. The sod houses of early Great Plains settlers were made mostly from this grass. 1 Hitchcock A.S. Manual of the Grasses of the United States. in: 2nd Ed. Dover Publications Inc, New York1971: 545-546 Google Scholar It can be used as a xeroscape lawn grass.

An international terminology for grazing lands and grazing animals

Preface 2 Members of the committee 3 Acknowledgements 3 An International Terminology for Grazing Lands and Grazing Animals 1. Grazing land terms 4 2. Vegetation: descriptive terms 6 3. Forage growth and harvest 8 4. Forage nutritive value and intake 9 5. Management of grazing lands 12 6. Land–forage–animal relationships 15 7. Stocking methods 16 References 18 Appendix I. References and additional information for selected terms 21

Biomass Not Linked to Perennial Grass Mortality Following Severe Wildfire in the Southern High Plains

In March 2006 the East Amarillo Complex (EAC) wildfires burned over 367 000 ha of short and mixed grass prairie of the southern High Plains, USA. We studied EAC wildfire effects on perennial grass mortality and peak standing crop on Deep Hardland and Mixedland Slopes ecological sites. Deep Hardlands were dominated by blue grama ( Bouteloua gracilis H.B.K. [Griffiths]) and buffalograss ( Buchloe dactyloides [Nutt.] Engelm.); common species on Mixedland Slopes were little bluestem ( Schizachyrium scoparium [Michx.] Nash.) and sideoats grama ( Bouteloua curtipendula [Michx.] Torr.) with scattered sand sagebrush ( Artemisia filifolia Torr.) sometimes present. We hypothesized that perennial grass mortality would increase and standing crop would decrease following severe wildfire, and that these responses would be greater than documented prescribed fire effects. Frequency of perennial grass mortality was higher on both sites in burned areas than nonburned areas through three growing seasons following wildfire; however, standing crop was minimally affected. Results suggest that post-wildfire management to ameliorate wildfire effects is not necessary, and that wildfire effects in this area of the southern High Plains are similar to prescribed fire effects. En Marzo de 2006 los incendios del Complejo del Este de Amarillo (CEA) quemaron más de 367.000 ha de estepas de pastos cortos y mixtos del sur de las Altas Planicies de EE.UU. Estudiamos los efectos del incendio del CEA sobre la mortalidad de pastos perennes y la biomasa total acumulada en dos sitios ecológicos denominados Deep Hardland (DH) y Mixedland Slopes (MS). Las especies dominantes en el sitio DH fueron Bouteloua gracilis H.B.K. [Griffiths] y Buchloe dactyloides, mientras que las especies comunes en el sitio MS fueron Schizachyrium scoparium [Michx.] Nash.y Bouteloua curtipendula [Michx.] Torr. con la presencia esporádica de individuos de Artemisia filifolia Torr. Nuestra hipótesis predijo que los incendios severos aumentarían la mortalidad de pastos perennes y disminuirían la biomasa en pie y que dichas respuestas serian mayores a las documentadas en quemas prescriptas. En ambos sitios, la frecuencia de mortalidad de pastos perennes fue mayor en áreas quemadas que en áreas no quemadas a lo largo de tres estaciones de crecimiento posterior al incendio; no obstante, la biomasa en pie fue mínimamente afectada. Los resultados sugieren que el manejo post-incendio tendiente a atenuar los efectos del mismo no es necesario, y que los efectos de los incendios en esta región sur de las Altas Planicies es similar a la de las quemas prescriptas.

Land Use and Small Mammal Predation Effects on Shortgrass Prairie Birds

ABSTRACT Grassland birds endemic to the central shortgrass prairie ecoregion of the United States have experienced steep and widespread declines over the last 3 decades, and factors influencing reproductive success have been implicated. Nest predation is the major cause of nest failure in passerines, and nesting success for some shortgrass prairie birds is exceptionally low. The 3 primary land uses in the central shortgrass prairie ecoregion are native shortgrass prairie rangeland (62%), irrigated and nonirrigated cropland (29%), and Conservation Reserve Program (CRP, 8%). Because shortgrass–cropland edges and CRP may alter the community of small mammal predators of grassland bird nests, I sampled multiple sites on and near the Pawnee National Grasslands in northeast Colorado, USA, to evaluate 1) whether small mammal species richness and densities were greater in CRP fields and shortgrass prairie–cropland edges compared to shortgrass prairie habitats, and 2) whether daily survival probabilities of ground‐nesting grassland bird nests were negatively correlated with densities of small mammals. Small mammal species richness and densities, estimated using trapping webs, were generally greater along edges and on CRP sites compared to shortgrass sites. Vegetation did not differ among edges and shortgrass sites but did differ among CRP and shortgrass sites. Daily survival probabilities of artificial nests at edge and CRP sites and natural nests at edge sites did not differ from shortgrass sites, and for natural nests small mammal densities did not affect nest survival. However, estimated daily survival probability of artificial nests was inversely proportional to thirteen‐lined ground squirrel (Spermophilus tridecemlineatus) densities. In conclusion, these data suggest that although land‐use patterns on the shortgrass prairie area in my study have substantial effects on the small mammal community, insufficient data existed to determine whether land‐use patterns or small mammal density were affecting grassland bird nest survival. These findings will be useful to managers for predicting the effects of land‐use changes in the shortgrass prairie on small mammal communities and avian nest success.

Managing prairie dogs for prairie heritage, biodiversity, and wildlife tourism

The black-tailed prairie dog is a keystone species of the North American short-grass prairie, large parts of which are devoted to cattle ranching. However, the prairie dog population has been dramatically reduced by eradication programs developed in response to the animals' competition for, and consumption of, grasses that would otherwise feed cattle and to the long-held belief that their burrows pose a threat to livestock. This article will discuss the important role the black-tailed prairie dog plays in biodiversity as ecosystem engineer and prey as well as in the natural and cultural heritage and economy of the short-grass prairie, which has been dramatically transformed by Euro-American settlement. It will focus on the case study involving a group of ranchers in western Kansas' Logan County whose alternative land management practices include rotation grazing and maintaining prairie dogs for the animals' role in supporting other wildlife, despite fierce opposition by neighboring ranchers and government officials, These ranchers' lands provide opportunities for wildlife watching and tourism centered on the prairie dogs and their predators such as the endangered and recently reintroduced black-footed ferret.

The absence of concordant population genetic structure in the black-tailed prairie dog and the flea, Oropsylla hirsuta, with implications for the spread of Yersinia pestis

The black-tailed prairie dog (Cynomys ludovicianus) is a keystone species on the mid- and short-grass prairies of North America. The species has suffered extensive colony extirpations and isolation as a result of human activity including the introduction of an exotic pathogen, Yersinia pestis, the causative agent of sylvatic plague. The prairie dog flea, Oropsylla hirsuta, is the most common flea on our study colonies in north-central Montana and it has been shown to carry Y. pestis. We used microsatellite markers to estimate the level of population genetic concordance between black-tailed prairie dogs and O. hirsuta in order to determine the extent to which prairie dogs are responsible for dispersing this potential plague vector among prairie dog colonies. We sampled fleas and prairie dogs from six prairie dog colonies in two regions separated by about 46 km. These colonies were extirpated by a plague epizootic that began months after our sampling was completed in 2005. Prairie dogs showed significant isolation-by-distance and a tendency toward genetic structure on the regional scale that the fleas did not. Fleas exhibited higher estimated rates of gene flow among prairie dog colonies than the prairie dogs sampled from the same colonies. While the findings suggested black-tailed prairie dogs may have contributed to flea dispersal, we attributed the lack of concordance between the population genetic structures of host and ectoparasite to additional flea dispersal that was mediated by mammals other than prairie dogs that were present in the prairie system.

Validation of ET Estimates from the Canadian Prairie Agrometeorological Model for Contrasting Vegetation Types and Growing Seasons

The objective of this study was to establish the ability of the prairie agrometeorological model (PAMII) to simulate daily evapotranspiration (ET). Specifically, modelled ET estimates from PAMII were validated using daily ET estimates from eddy-covariance systems at West Nose Creek (barley field located northwest of Calgary, Alberta) and a FluxNet site (short-grass prairie located west of Lethbridge, Alberta). Additionally, PAMII was validated for three contrasting growing seasons at the grassland site to establish the model’s ability to quantify the effect of different growth conditions on ET. PAMII performed well and was able to capture the day-to-day variability of the ET at both sites. PAMII successfully captured the increase (decrease) in accumulated growing season ET for the wet (dry) growing seasons at the short-grass prairie site. Moreover, the optimal reference minimum stomatal resistance term was significantly lower for the barley crop (50 s m–1) than the corresponding value for the short-grass prairie (80 s m–1). At the grassland site the optimal stomatal resistance term varied markedly depending on the growing conditions; the optimal value for the wet year was 60 s m–1 compared to 90 s m–1 for the dry year. That is, no single value worked best for all years, and our findings caution against using a single value for the reference minimum stomatal resistance. In summary, PAMII captured the salient features of the ET variability at both sites and for contrasting at the grassland site. However, our research has identified several areas where future versions of the PAMII model might be improved.

Comparative Morphology of Northern Populations of Breeding Cooper's Hawks

Abstract. Few studies at a broad geographical scale have characterized intraspecific variation in morphology of woodland hawks in the genus Accipiter. From 1999 to 2007 we investigated morphological variation in large samples of live Cooper's Hawks (A. cooperii) nesting in four study areas: coniferous woodland around Victoria, British Columbia, Canada, isolated deciduous woodlands in short-grass prairies of northwestern North Dakota, towns and rural deciduous woodlands along the border of North Dakota and Minnesota, and urban and rural mixed deciduous and coniferous landscapes of Wisconsin. These sites span 2660 km across the northern part of the species' breeding range. We measured body mass (i.e., size), wing chord, tail length, tarsus diameter, hallux length, and culmen length of breeding adults, finding significant and clinal variation in body mass (or size). The smallest and most similar-sized birds occurred in British Columbia and western North Dakota, larger birds along the border between North Dak...

Small Mammals and Ground-Dwelling Invertebrates Associated with Active and Controlled Colonies of Black-Tailed Prairie Dogs (Cynomys ludovicianus)

Small mammals and ground-dwelling invertebrates were sampled seasonally on active colonies of black-tailed prairie dogs (Cynomys ludovicianus), Phostoxin®-treated colonies, and non-colonized short-grass prairie to assess potential impacts of Phostoxin® on non-target species in the Texas Panhandle. Eleven species of small mammals were captured. Northern grasshopper mice (Onychomys leucogaster) were more abundant on active prairie dog colonies, whereas abundances of North American deermice (Peromyscus maniculatus) and plains harvest mice (Reithrodontomys montanus) did not differ among treatments. Total abundance of small mammals and relative abundances of other species did not differ among active colonies, Phostoxin®-treated colonies, and non-colonized sites. Ground-dwelling invertebrates were more abundant on active colonies than on Phostoxin®-treated colonies or non-colonized sites. Results of this study indicate that short-term impacts of control of prairie dogs with Phostoxin® on non-target small mammals and ground-dwelling invertebrates is limited, but may be significant for individual species. Additionally, in short-grass prairie ecosystems, vegetative alterations made by prairie dogs may not influence populations of small mammals as much as in tall or mixed-grass prairies. However, active colonies were used more by northern grasshopper mice and ground-dwelling invertebrates, indicating that this habitat is important for these species.

Abundance and Density of Mountain Plover (Charadrius montanus) and Burrowing Owl (Athene cunicularia) in Eastern Colorado

ABSTRACT. Because of continental-scale declines of grassland birds over the past century, conservation agendas are focused on increasing understanding of grassland bird ecology and habitat associations. Shortgrass prairie is a unique grassland ecosystem maintained, in part, by Black-tailed Prairie Dogs (Cynomys ludovicianus). The Mountain Plover (Charadrius montanus) and western Burrowing Owl (Athene cunicularia hypugaea) are species of conservation concern known to be associated with prairie dog colonies. We estimated abundance of Mountain Plovers and Burrowing Owls in three habitats within the Colorado shortgrass prairie ecosystem—prairie dog colonies, grassland not occupied by prairie dogs, and dryland agriculture. Further, we investigated habitat associations of Mountain Plovers and Burrowing Owls at multiple landscape scales. We estimated 8,577 Mountain Plovers (95% CI: 7,511–35,130) and 3,554 Burrowing Owls (95% CI: 3,298–8,445) in eastern Colorado. Mountain Plover density on prairie dog colony plot...