Abrupt downstream forest decline following river damming in southern Alberta

The influence of river damming on the abundance of riparian poplar forests was investigated by comparing forest abundances on the dammed St. Mary and Waterton rivers of southern Alberta with the neighbouring undammed Belly River. Forest distributions were determined by estimating the linear river distance of forests from airphotos taken in 1961 and 1981, both upstream and downstream from the dams. During the 20-year interval, a 48% reduction occurred downstream from the St. Mary Dam, which was completed in 1951. Downstream from the Waterton Dam, completed in 1964, riparian forests declined 23 %. Poplar abundance along the downstream region of the undammed Belly River was relatively unchanged over the study period, showing less than a 1 % reduction. The upstream (undammed) portions of all three rivers underwent a slight forest decline during the 20-year interval; declines of 4.7, 4.6, and 6.1 % occurred along the St. Mary, Belly, and Waterton rivers, respectively. Thus, the damming of two rivers in southern Alberta has been followed by a rapid and dramatic downstream decline in riparian forests. Further, the close association between the location and extent of the forest decline supports a causal relationship between the river damming and the forest decline. Possible causes of the decline are discussed, including drought-induced mortality, particularly of seedlings.

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Riparian edge effects on boreal balsam fir bird communities

Canadian Journal of Forest Research ◽

10.1139/x95-063 ◽

1995 ◽

Vol 25 (4) ◽

pp. 555-566 ◽

Cited By ~ 38

Author(s):

Pierre Larue ◽

Louis Bélanger ◽

Jean Huot

Keyword(s):

Edge Effect ◽

Vegetation Structure ◽

Riparian Forest ◽

Close Association ◽

Bird Communities ◽

Riparian Forests ◽

Balsam Fir ◽

Bird Abundance ◽

Vegetation Diversity ◽

Bird Richness

Riparian forests are often identified as prime habitat for wildlife because of the presence of particular plant communities and edges creating a highly developed and diversified vegetation structure. However, in the northeastern boreal forests of Canada, where narrow land–water ecotones with abrupt edges are quite common, the relative habitat value of riparian forests remains to be demonstrated. We compared bird communities of eight pairs of riparian and nonriparian plots, similar in vegetation structure and composition, to verify the relative value for breeding birds of typical coniferous riparian forest stands of the southern boreal region of eastern Quebec. Bird abundance (P = 0.02), richness (P = 0.03), and diversity (P = 0.02) were significantly higher in the riparian stands, where the spatial sequence of three distinct habitats (a balsam fir (Abiesbalsamea (L.) Mill.)–northern white cedar (Thujaoccidentalis L.) forest, a narrow alder (Alnusrugosa (Du Roi) Spreng.) - grass wetland, and water) created high horizontal vegetation diversity. In riparian stands median bird richness and density were, respectively, 23.5 species and 437.5 territories/km2 compared with 19.0 species and 348.2 territories/km2 for interior stands. Nine species were observed exclusively in riparian plots. In addition to the species usually found in the studied nonriparian forests, the riparian plots were used by species typically related to the water edge such as the Northern Waterthrush (Seiurusnoveboracensis Gmelin) and Rusty Blackbird (Euphaguscarolinus Miiller) as well as species associated with the shrub and grass wetland such as the American Robin (Turdusmigratorius L.), the Veery (Catharusfuscescens Stephens), and the Common Yellowthroat (Geothlypistrichas L.). The shrub-foraging guild showed higher abundance in riparian stands. The tree-foraging and tree-bole foraging guilds, however, were comparable in both groups of stands. In this study, the natural conditions prevailing along he riparian sites appeared mostly positive for the breeding-bird community; it created what is perceived as being an "edge effect." The edge effect can be defined, in this case, as being the additional density and number of species induced by the added horizontal vegetation diversity created by the close association of three extremely different ecosystems: a forest stand, an aquatic ecosystem, and a narrow but distinct shrub-grass wetland. This also confirms the necessity of distinguishing natural edges that are permanent features of the landscape from induced edges created by human activity.

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Riparian forest conditions along three northern Michigan rivers following Emerald Ash Borer invasion

Canadian Journal of Forest Research ◽

10.1139/cjfr-2019-0387 ◽

2020 ◽

Vol 50 (8) ◽

pp. 800-810

Author(s):

Patrick J. Engelken ◽

Deborah G. McCullough

Keyword(s):

Riparian Forest ◽

Emerald Ash Borer ◽

Basal Area ◽

Agrilus Planipennis ◽

Riparian Forests ◽

Tree Seedlings ◽

Fraxinus Pennsylvanica ◽

Fraxinus Nigra ◽

The Stability ◽

Three Rivers

Emerald Ash Borer (EAB; Agrilus planipennis Fairmaire (Coleoptera, Buprestidae)) has killed millions of ash (Fraxinus spp.) trees since its 2002 detection in southern Michigan and Ontario. Effects of EAB in riparian forests, where ash species are often abundant, could influence terrestrial and aquatic conditions but are largely unknown. We surveyed vegetation and coarse woody material within and between three gaps in riparian forests along stretches of three rivers in northwestern Michigan. Gaps were originally dominated by Fraxinus pennsylvanica Marsh. and Fraxinus nigra Marsh., which comprised 46%–71% of total basal area, while ash comprised <10% of basal area in forests between gaps. More than 95% of overstory ash were killed by EAB. Fraxinus pennsylvanica saplings were abundant in gaps but F. nigra regeneration was minimal. Few tree seedlings occurred in gaps, which were dominated by dense sedge mats. Aerial imagery showed the EAB invasion has resulted in 3.6–7.1 canopy gaps·km−1 and dead ash account for 13%–21% of total basal area within 100 m of the banks of all three rivers. Long-term monitoring will be useful to evaluate persistence of ash, particularly F. nigra, the stability of riparian buffers, and potential indirect effects of EAB invasion on the adjacent aquatic systems.

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Bacteriophages Associated with Turkey Coecums in Bluecomb-Infected and Healthy Birds

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100063044 ◽

1969 ◽

Vol 27 ◽

pp. 226-227

Author(s):

A. E. Ritchie

Keyword(s):

Host Cell ◽

Causal Relationship ◽

Cell Cultures ◽

Cell Interaction ◽

Etiologic Agent ◽

Viral Origin ◽

Intestinal Contents ◽

Host Cell Interaction

The cause of bluecomb disease in turkeys is unknown. Filtration of infective intestinal contents suggests a viral origin. To date, it has not been possible to isolate the etiologic agent in various cell cultures. The purpose of this work was to characterize as many virus-like entities as were recognizable in intestines of both healthy and bluecomb-infected turkeys. By a comparison of the viral populations it was hoped that some insight might be gained into the cause of this disease. Studies of turkey hemorraghic enteritis by Gross and Moore (Avian Dis. 11: 296-307, 1967) have suggested that a bacteriophage-host cell interaction may bear some causal relationship to that disease.

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Immunocytochemical Localization of Amyloid Protein AA in the “Dense Fibrillar Inclusions” of the Reticuloendothelical Cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100079632 ◽

1977 ◽

Vol 35 ◽

pp. 438-439

Author(s):

T. Shirahama ◽

M. Skinner ◽

A.S. Cohen

Keyword(s):

Amyloid Fibril ◽

Close Association ◽

Gel Filtration ◽

Fibril Formation ◽

Amyloid Protein ◽

Electron Microscopic ◽

Amyloid Deposits ◽

Amyloid Fibril Formation ◽

Electron Microscopic Technique ◽

Lysosomal System

A1thought the mechanisms of amyloidogenesis have not been entirely clarified, proteolysis of the parent proteins may be one of the important steps in the amyloid fibril formation. Recently, we reported that "dense fibrillar inclusions" (DFI), which had the characteristics of lysosomes and contained organized fibrillar profiles as well, were observed in the reticuloendothelial cells in close association with the foci of new amyloid deposits. We considered the findings as evidence for the involvement of lysosomal system in amyloid fibril formation (l). In the present study, we attempted to determine the identity of the contents of the DFI by the use of antisera against the amyloid protein (AA) and an immuno-electron microscopic technique.Amyloidosis was induced in CBA/J mice by daily injections of casein (l). AA was isolated from amyloid-laden spleens by gel filtration and antibody to it was produced in rabbits (2). For immunocytochemistry, the unlabeled antibody enzyme method (3) was employed.

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Linear Arrays of Helical Polyribosomes in Cells Exposed to Antitumor Drug Vincristine Sulfate

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100063706 ◽

1969 ◽

Vol 27 ◽

pp. 358-359

Author(s):

Awtar Krishan

Keyword(s):

Close Association ◽

Annulate Lamellae ◽

Large Array ◽

Vincristine Sulfate ◽

Linear Arrays ◽

Golgi Membranes ◽

Related Drug ◽

Drug Leads ◽

Lethal Doses ◽

Vinblastine Sulfate

Earle's L-929 fibroblasts treated with mitosis-arresting but sub-lethal doses of vinblastine sulfate (VLB) show hypertrophy of the granular endoplasmic reticulum and annulate lamellae. Exposure of the cells to heavier doses of vincristine sulfate (VCR), a VLB-related drug, leads to the accumulation of large amounts of helical polyribosomes, Golgi membranes and crystals in the cytoplasm. In many of these cells a large number of helical polyribosomes are arranged in prominent linear rows, some of which may be up to 5 micrometers in length. Figure 1 shows a large array of helical polyribosomes near a crystalline mass (CRS) in an Earle's L-929 fibroblast exposed to VCR (5ϒ/ml.) for 3 hours At a higher magnification, as seen in figure 2, the helical polyribosomes are seen arranged in parallel rows. In favorably cut sections, a prominent backbone like "stalk" of finely granular material, measuring approximately 300Å in width is seen in close association with the linear rows of helical polyribosomes.

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SEM analysis of fish scale cross sections: A technique study

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100124124 ◽

1992 ◽

Vol 50 (1) ◽

pp. 744-745

Author(s):

M.E. Lee ◽

A. Moller ◽

P.S.O. Fouche ◽

I.G Gaigher

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Cross Sections ◽

Soft Tissues ◽

Close Association ◽

Sem Analysis ◽

Fish Scale ◽

Fish Scales ◽

Micro Structures ◽

Scanning Electron

Scanning electron microscopy of fish scales has facilitated the application of micro-structures to systematics. Electron microscopy studies have added more information on the structure of the scale and the associated cells, many problems still remain unsolved, because of our incomplete knowledge of the process of calcification. One of the main purposes of these studies has been to study the histology, histochemistry, and ultrastructure of both calcified and decalcified scales, and associated cells, and to obtain more information on the mechanism of calcification in the scales. The study of a calcified scale with the electron microscope is complicated by the difficulty in sectioning this material because of the close association of very hard tissue with very soft tissues. Sections often shatter and blemishes are difficult to avoid. Therefore the aim of this study is firstly to develop techniques for the preparation of cross sections of fish scales for scanning electron microscopy and secondly the application of these techniques for the determination of the structures and calcification of fish scales.

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The ultrastructure of the double membrane-bound bodies and endoplasmic reticulum in serial sections of wheat spot mosaic-affected wheat plants

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100161023 ◽

1990 ◽

Vol 48 (3) ◽

pp. 694-695

Author(s):

M. H. Chen ◽

C. Hiruki

Keyword(s):

Endoplasmic Reticulum ◽

High Resolution ◽

Membrane Structure ◽

Mosaic Disease ◽

Serial Sections ◽

Thin Sections ◽

Double Membrane ◽

Southern Alberta ◽

Membrane Bound ◽

Scanning Em

Wheat spot mosaic disease was first discovered in southern Alberta, Canada, in 1956. A hitherto unidentified disease-causing agent, transmitted by the eriophyid mite, caused chlorosis, stunting and finally severe necrosis resulting in the death of the affected plants. Double membrane-bound bodies (DMBB), 0.1-0.2 μm in diameter were found to be associated with the disease.Young tissues of leaf and root from 4-wk-old infected wheat plants were fixed, dehydrated, and embedded in Spurr’s resin. Serial sections were collected on slot copper grids and stained. The thin sections were then examined with a Hitachi H-7000 TEM at 75 kV. The membrane structure of the DMBBs was studied by numbering them individually and tracing along the sections to see any physical connection with endoplasmic reticulum (ER) membranes. For high resolution scanning EM, a modification of Tanaka’s method was used. The specimens were examined with a Hitachi Model S-570 SEM in its high resolution mode at 20 kV.

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