scholarly journals Trends in Bird Densities at a Remnant Fescue Grassland in Saskatchewan

2017 ◽  
Vol 131 (2) ◽  
pp. 170-178
Author(s):  
Bohdan Pylypec

Populations of grassland birds in North America have declined greatly in the past five decades. Hypothesized drivers of decline include habitat loss, fragmentation, and adverse impacts from human activities. At a remnant fescue grassland in Saskatoon, Saskatchewan numbers of Savannah Sparrow (Passerculus sandwichensis), Western Meadowlark (Sturnella neglecta), Brewer’s Blackbird (Euphagus cyanocephalus), and Vesper Sparrow (Pooecetes gramineus) have been stable. Numbers of clay-colored Sparrow (Spizella pallida) have increased since the 1960s. Sprague’s Pipit (Anthus spragueii), Upland Sandpiper (Bartramia longicauda), and Burrowing Owl (Athene cunicularia) are no longer present. Baird’s Sparrow (Ammodramus bairdii), Bobolink (Dolichonyx oryzivorus), and Horned Lark (Eremophila alpestris) have become irregular visitors. In the past 50 years, 91 species have been observed displaying territorial behaviour, feeding, nesting, or migrating at this remnant native grassland. With encroaching urban development and increased human influence at the prairie and surrounding area, the impacts on the bird communities at the site in the future are unknown.

1973 ◽  
Vol 51 (7) ◽  
pp. 697-713 ◽  
Author(s):  
R. A. Owens ◽  
M. T. Myres

The effects of several forms of agricultural use of native fescue (Festuca scabrella) grasslands upon populations of native passerine birds were studied in the Hand Hills of southern Alberta in 1970.Censuses of avian populations were carried out on twelve 40-acre (16.2 ha) study plots as well as on two 10-mi (16.1 km) long roadside routes. The vegetation on the study plots and along the roadside routes was described.Native fescue grasslands, undisturbed for 3 years, supported a passerine community consisting of Baird's sparrow (Ammodramus bairdii), Sprague's pipit (Anthus spragueii), savannah sparrow (Passerculus sandwichensis), clay-colored sparrow (Spizella pallida), and western meadowlark (Sturnella neglecta). Incomplete disturbance of fescue grasslands, by mowing for hay or grazing by cattle, reduced or eliminated Baird's sparrow and Sprague's pipit but permitted the ingress of horned lark (Eremophila alpestris) and chestnut-collared longspur (Calcarius ornatus). Total elimination of the native grassland, by ploughing and cultivation for cereal crops, eliminated all passerine species except the horned lark. Peripheral disturbed areas resulting from cultivation, such as held boundaries and roadside ditches, may have benefited several species that tend to occur in ecotonal habitats: savannah sparrow, clay-colored sparrow, and vesper sparrow (Pooecetes gramineus).


2005 ◽  
Vol 119 (4) ◽  
pp. 490
Author(s):  
Scott D. Stevens ◽  
Troy I. Wellicome

We surveyed native and non-native grassland for federally listed grassland bird species at Reserves and/or Treaty Land Entitlements (TLE) belonging to five First Nations in the prairie ecozone of Canada. Ferruginous Hawk (Buteo regalis – of special concern), Loggerhead Shrike (Lanius ludovicianus – threatened), and Long-billed Curlew (Numenius americanus – of special concern) were observed at five of 335, three of 361, and five of 329 survey points within their respective geographic ranges. Sprague’s Pipit (Anthus spragueii – threatened) was observed at 69 of 361 survey points and accounted for 84% of sites with listed birds. Estimates of proportions of native and non-native grassland within 400 m of survey points indicated that Sprague’s Pipit preferred native grassland. Despite special effort, the Burrowing Owl (Athene culicularia – endangered) was not observed, although a nest from a previous year was encountered. We recorded the greatest number of species and individuals on reserves located in mixed and moist-mixed grasslands that contained large portions of native grassland. In many instances, field assessments revealed unsuitable habitat at sites that remote-sensing data classified as suitable.


The Condor ◽  
2002 ◽  
Vol 104 (3) ◽  
pp. 643-651 ◽  
Author(s):  
Zach F. Jones ◽  
Carl E. Bock

Abstract Landscape alterations resulting from urban expansion are among those factors negatively impacting Great Plains grassland birds. The City and County of Boulder, Colorado, manage one of the largest grassland open-space systems in North America, but it is embedded in an area of rapid urban growth. We compared bird count data from the 1980s and 1990s with checklist information about the Boulder grassland avifauna between 1900 and 1937, with the goal of determining what proportion and which species of the historical grassland avifauna are being sustained on Boulder open space. Of 29 native species present in 1900, 22 (76%) appeared on our counts in the 1990s. Formerly common species that disappeared or declined mostly were birds associated with shortgrass prairie, including Burrowing Owl (Athene cunicularia), Common Nighthawk (Chordeiles minor), Loggerhead Shrike (Lanius ludovicianus), and Lark Bunting (Calamospiza melanocorys). By contrast, species associated with mixed and tallgrass habitats increased or held steady, including Vesper Sparrow (Pooecetes gramineus), Savannah Sparrow (Passerculus sandwichensis), Grasshopper Sparrow (Ammodramus savannarum), Bobolink (Dolichonyx oryzivorus), and Western Meadowlark (Sturnella neglecta). We conclude that municipal open spaces can support populations of many Great Plains grassland birds, but that sustaining species associated with the shortgrass prairie may prove especially challenging. Conservación de Aves de Pastizal en un Paisaje de Crecimiento Urbano: Una Perspectiva Histórica Resumen. La alteración del paisaje causada por la expansión urbana es uno de los factores que impacta negativamente a las aves de los pastizales de los “Great Plains.” La ciudad y el condado de Boulder, Colorado, maneja uno de los sistemas de espacios abiertos de pastizal más grande de Norteamérica, el cual se encuentra rodeado por un área de crecimiento urbano. Comparamos datos de conteo de aves de los 1980s y 1990s con informacíon de la avifauna de Boulder entre 1900 y 1937, con el propósito de determinar qué proporción y cuántas especies de las aves de pastizal registradas históricamente se mantuvieron en los espacios abiertos de Boulder. De 29 especies nativas presentes en 1900, 22 (76%) aparecen en nuestros conteos de los 1990s. Especies anteriormente comunes pero que desaparecieron o disminuyeron en cantidad, fueron aves relacionadas principalmente con praderas de pasto corto, incluyendo Athene cunicularia, Chordeiles minor, Lanius ludovicianus y especialmente Calomospiza melanocorys. Por el contrario, especies asociadas a hábitats mixtos o de pasto alto han aumentado o se han mantenido, incluyendo Pooecetes gramineus, Passerculus sandwichensis, Ammodramus savannarum, Dolichonyx oryzivorus y Sturnella neglecta. Concluimos que los espacios abiertos municipales pueden sostener poblaciones de varias especies de aves de pastizal. Sin embargo, será más difícil mantener aquellas especies que prefieren praderas de pasto corto, porque las áreas continuas y amplias que necesitan, ya no existen.


The Auk ◽  
2005 ◽  
Vol 122 (2) ◽  
pp. 618-636 ◽  
Author(s):  
Rosalind B. Renfrew ◽  
Christine A. Ribic ◽  
Jamie L. Nack

Abstract Some grassland passerine species are considered area-sensitive, but the mechanisms underlying that phenomenon are not understood, particularly on grazed grasslands. Area sensitivity may result from edge avoidance or higher nest predation near edges, both of which may be influenced by predator activity or cattle-induced vegetational differences between pasture edge and interior. We assessed the effect of distance to edge on nest density and predation Savannah Sparrows (Passerculus sandwichensis), Grasshopper Sparrows (Ammodramus savannarum), Bobolinks (Dolichonyx oryzivorus), and meadowlarks (Sturnella spp.) along wooded and nonwooded edges of Wisconsin pastures in 1998-2000 and the activity of potential mammalian nest predators along those edges in 2000-2001. We found a positive relationship between nest density and distance from edge for all edge types combined, but that was not the result of effects of wooded edges: we found no difference in density between nests located <50 or <100 m from wooded versus nonwooded (crop or grassland) edges. Models that included combinations of vegetation structure (e.g. concealment), initiation date, year, or edge variables (or all four) were poor predictors of the probability of nest predation. Placing nests away from edges, therefore, did not reduce the risk of nest predation. Eight species known to prey on grassland bird nests were documented along pasture edges, raccoon (Procyon lotor) being the most common. Frequency of raccoon and thirteen-lined ground squirrel (Spermophilus tridecemlineatus) visitation was higher along wooded edges and nonwooded edges, respectively. Cattle (Bos taurus) activity did not differentially affect vegetation height-density along edges compared with that in the pasture interior. Possible reasons for predation risk being similar in both pasture interiors and edges in a fragmented landscape include the ease with which predators can move within pastures, high percentage of resident grassland predators, and small size (median = 47.2 ha) of pastures.


The Auk ◽  
2001 ◽  
Vol 118 (1) ◽  
pp. 24-34 ◽  
Author(s):  
Douglas H. Johnson ◽  
Lawrence D. Igl

Abstract Area requirements of grassland birds have not been studied except in tallgrass prairie. We studied the relation between both species-occurrence and density and patch size by conducting 699 fixed-radius point counts of 15 bird species on 303 restored grassland areas in nine counties in four northern Great Plains states. Northern Harrier (Circus cyaneus), Sedge Wren (Cistothorus platensis), Clay-colored Sparrow (Spizella pallida), Grasshopper Sparrow (Ammodramus savannarum), Baird's Sparrow (Ammodramus bairdii), Le Conte's Sparrow (Ammodramus leconteii), and Bobolink (Dolichonyx oryzivorus) were shown to favor larger grassland patches in one or more counties. Evidence of area sensitivity was weak or ambivalent for Eastern Kingbird (Tyrannus tyrannus), Common Yellowthroat (Geothlypis trichas), Savannah Sparrow (Passerculus sandwichensis), and Western Meadowlark (Sturnella neglecta). Red-winged Blackbirds (Agelaius phoeniceus) preferred larger patches in some counties, and smaller patches in others. Mourning Doves (Zenaida macroura) and Brown- headed Cowbirds (Molothrus ater) tended to favor smaller grassland patches. Three species showed greater area sensitivity in counties where each species was more common. Five species demonstrated some spatial pattern of area sensitivity, either north to south or east to west. This study demonstrates the importance of replication in space; results from one area may not apply to others because of differences in study design, analytical methods, location relative to range of the species, and surrounding landscapes.


2020 ◽  
Author(s):  
Jill A. Shaffer ◽  
Lawrence D. Igl ◽  
Douglas H. Johnson ◽  
Marriah L. Sondreal ◽  
Christopher M. Goldade ◽  
...  

Author(s):  
П. В. Капустин ◽  
А. И. Гаврилов

Состояние проблемы. Проблематика городской среды заявила о себе в 1960-е годы как протест против модернистских методов урбанизма и других видов проектирования. Средовое движение не случайно тогда именовали «антипрофессиональным» - оно было направлено против устоявшихся и недейственных методов работы с городом - от исследования до управления. За прошедшие десятилетия в рамках самого средового движения и его идейных наследников наработано немало методов и приемов работы, однако они до сих не подвергались анализу как пребывающая в исторической динамике целостная совокупность инструментария, альтернативного традиционному градостроительству. Результаты. Рассмотрены особенности и проблемы анализа методологического «арсенала» средового движения и урбанистики. Методы работы с городской средой впервые структурированы по типам знания. Показана близость методов исследовательского и проектного подходов в отношении городской среды. Выводы. В ближайшее время можно ожидать появления новых синтетических знаний и частных методологий, связанных как с обострением средовой проблематики, с расширением круга средовых акторов, так и с процессом профессионализации урбанистики. Statement of the problem. The urban environment paradigm emerged in the 1960s as a protest against the modernist methods of urbanism and other types of design. It was no coincidence that the environmental movement was back then called "anti-professional" as it was directed against the established and ineffective methods of working with the city, i. e., from research to management. Over the past decades, within the framework of the environmental movement and its ideological heirs, a lot of methods and have been developed. However, they have not yet been analyzed as an integral set of tools in the historical dynamics which is an alternative to traditional urban planning. Results. The features and problems of the analysis of the methodological “arsenal” of environmental movement and urban studies are considered. The methods of working with the urban environment are first structured according to the types of knowledge. The proximity of research and design approaches in the case when the urban environment is dealt with is shown. Conclusions. In the nearest future, we can expect new synthetic knowledge and particular methodologies related to both the exacerbation of environmental problems to emerge as well as the expansion of the circle of environmental actors and the process of professionalization of urbanstics.


2014 ◽  
Author(s):  
Stephen K. Davis ◽  
Mark B. Robbins ◽  
Brenda C. Dale

Author(s):  
Elwira Sienkiewicz ◽  
Michał Gąsiorowski ◽  
Ladislav Hamerlík ◽  
Peter Bitušík ◽  
Joanna Stańczak

AbstractLakes located in the Polish and Slovak parts of the Tatra Mountains were included in the Tatra diatom database (POL_SLOV training set). The relationship between the diatoms and the water chemistry in the surface sediments of 33 lakes was the basis for the statistical and numerical techniques for quantitative pH reconstruction. The reconstruction of the past water pH was performed using the alpine (AL:PE) and POL_SLOV training sets to compare the reliability of the databases for the Tatra lakes. The results showed that the POL_SLOV training set had better statistical parameters (R2 higher by 0.16, RMSE and max. bias lower by 0.2 and 0.36, respectively) compared to the AL:PE training set. The better performance of the POL_SLOV training set is particularly visible in the case of Przedni Staw Polski where the curve of the inferred water pH shows an opposite trend for the period from the 1960s to 1990 compared to that based on the AL:PE dataset. The reliability of the inferred pH was confirmed by the comparison with current instrumental measurements.


2021 ◽  
Vol 54 (1) ◽  
pp. 21-33
Author(s):  
Julie Berg ◽  
Clifford Shearing

The 40th Anniversary Edition of Taylor, Walton and Young’s New Criminology, published in 2013, opened with these words: ‘The New Criminology was written at a particular time and place, it was a product of 1968 and its aftermath; a world turned upside down’. We are at a similar moment today. Several developments have been, and are turning, our 21st century world upside down. Among the most profound has been the emergence of a new earth, that the ‘Anthropocene’ references, and ‘cyberspace’, a term first used in the 1960s, which James Lovelock has recently termed a ‘Novacene’, a world that includes both human and artificial intelligences. We live today on an earth that is proving to be very different to the Holocene earth, our home for the past 12,000 years. To appreciate the Novacene one need only think of our ‘smart’ phones. This world constitutes a novel domain of existence that Castells has conceived of as a terrain of ‘material arrangements that allow for simultaneity of social practices without territorial contiguity’ – a world of sprawling material infrastructures, that has enabled a ‘space of flows’, through which massive amounts of information travel. Like the Anthropocene, the Novacene has brought with it novel ‘harmscapes’, for example, attacks on energy systems. In this paper, we consider how criminology has responded to these harmscapes brought on by these new worlds. We identify ‘lines of flight’ that are emerging, as these challenges are being met by criminological thinkers who are developing the conceptual trajectories that are shaping 21st century criminologies.


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