scholarly journals Long-Term Grazing Effects on Genetic Variability in Mountain Rough Fescue

2005 ◽  
Vol 58 (6) ◽  
pp. 637-642 ◽  
Author(s):  
Yong-Bi Fu ◽  
Don Thompson ◽  
Walter Willms ◽  
Mairi Mackay
Keyword(s):  
Genetic Variability ◽  
Grazing Effects ◽  
Rough Fescue

Long-term grazing effects on rough fescue grassland soils in southern British Columbia

2014 ◽  
Vol 94 (3) ◽  
pp. 337-345 ◽  
Author(s):  
Maja Krzic ◽  
Sarah F. Lamagna ◽  
Reg F. Newman ◽  
Gary Bradfield ◽  
Brian M. Wallace
Keyword(s):  
British Columbia ◽  
Canopy Cover ◽  
Grass Species ◽  
Mechanical Resistance ◽  
Above Ground Biomass ◽  
Grassland Soils ◽  
Ground Biomass ◽  
Grazing Effects ◽  
Rough Fescue

Krzic, M., Lamagna, S. F., Newman, R. F., Bradfield, G. and Wallace, B. M. 2014. Long-term grazing effects on rough fescue grassland soils in southern British Columbia. Can. J. Soil Sci. 94: 337–345. Rough fescue (Festuca campestris Rydb.) is a highly palatable forage species with little resistance to continuous grazing. The objective of this study was to evaluate the effects of long-term cattle grazing on soil properties, above-ground biomass, and canopy cover of key grass species on rough fescue grasslands in the southern interior British Columbia. Soil and vegetation properties were determined on a total of six open grassland sites located at the Lac du Bois and Hamilton Mountain. At all sites, grazing use has decreased over time, with the heaviest grazing occurring prior to 1960. The long-term (25–75 yr) elimination of grazing on these semi-arid grasslands has led to greater above-ground biomass and canopy cover of rough fescue, as well as increased soil polysaccharides; however, no differences in total soil C, N, and aggregate stability were found between pastures with and without grazing. Both soil bulk density and mechanical resistance were greater on grazed plots compared with those without grazing, with differences being more pronounced at the Hamilton Mountain location. The current grazing regime has not allowed for the elimination of negative effects of overgrazing on soil compaction on these rough fescue grasslands, especially at the location that continued to be grazed more heavily (i.e., Hamilton Mountain). Our findings suggest that soils in these grazing-sensitive grasslands need more than 75 yr to fully recover from the impacts of overgrazing.

scholarly journals Long-Term Cocirculation of Two Strains of Pepino Mosaic Virus in Tomato Crops and Its Effect on Population Genetic Variability

2020 ◽  
Vol 110 (1) ◽  
pp. 49-57 ◽  
Author(s):  
C. Alcaide ◽  
M. P. Rabadán ◽  
M. Juárez ◽  
P. Gómez
Keyword(s):  
Genetic Variability ◽  
Mosaic Virus ◽  
Evolutionary Dynamics ◽  
Geographical Area ◽  
Viral Fitness ◽  
Mixed Infections ◽  
Supporting Evidence ◽  
Pepino Mosaic Virus ◽  
Nucleotide Variability

Mixed viral infections are common in plants, and the evolutionary dynamics of viral populations may differ depending on whether the infection is caused by single or multiple viral strains. However, comparative studies of single and mixed infections using viral populations in comparable agricultural and geographical locations are lacking. Here, we monitored the occurrence of pepino mosaic virus (PepMV) in tomato crops in two major tomato-producing areas in Murcia (southeastern Spain), supporting evidence showing that PepMV disease-affected plants had single infections of the Chilean 2 (CH2) strain in one area and the other area exhibited long-term (13 years) coexistence of the CH2 and European (EU) strains. We hypothesized that circulating strains of PepMV might be modulating the differentiation between them and shaping the evolutionary dynamics of PepMV populations. Our phylogenetic analysis of 106 CH2 isolates randomly selected from both areas showed a remarkable divergence between the CH2 isolates, with increased nucleotide variability in the geographical area where both strains cocirculate. Furthermore, the potential virus–virus interaction was studied further by constructing six full-length infectious CH2 clones from both areas, and assessing their viral fitness in the presence and absence of an EU-type isolate. All CH2 clones showed decreased fitness in mixed infections and although complete genome sequencing indicated a nucleotide divergence of those CH2 clones by area, the magnitude of the fitness response was irrespective of the CH2 origin. Overall, these results suggest that although agroecological cropping practices may be particularly important for explaining the evolutionary dynamics of PepMV in tomato crops, the cocirculation of both strains may have implications on the genetic variability of PepMV populations.

Effects of long-term protection from grazing on phenotypic expression in geographically separated mountain rough fescue populations

2014 ◽  
Vol 94 (1) ◽  
pp. 33-39 ◽  
Author(s):  
D. J. Thompson ◽  
W. D. Willms
Keyword(s):  
Plant Communities ◽  
Phenotypic Expression ◽  
Highly Sensitive ◽  
History Of ◽  
Genetic Makeup ◽  
Rough Fescue ◽  
Geographic Sources ◽  
Lake Site ◽  
Summer Grazing

Thompson, D. J. and Willms, W. D. 2014. Effects of long-term protection from grazing on phenotypic expression in geographically separated mountain rough fescue populations. Can. J. Plant Sci. 94: 33–39. Whether or not long-term grazing or protection from grazing alters the genetic makeup of grass populations has been debated. Mountain rough fescue [(Festuca campestris (Rydb.)], which is highly sensitive to summer grazing, and becomes dominant in plant communities with long-term protection, was chosen to address this question. Plants from three geographic sites (Stavely in AB, Milroy in the Kootenay trench, BC and Goose Lake on the BC interior plateau) with divergent grazing histories were vegetatively propagated from tillers. Daughter plants were planted into two field nurseries (at Kamloops, BC, and Stavely, AB) and morphological measurements were taken in two field seasons post-establishment. Plants from all three populations were taller, flowered earlier, and were more productive at the Kamloops nursery site. Of the three geographic sources, plants from the Goose Lake site were most distinct with narrower leaves, later flowering, and greater yield. Plants with a long history of grazing had slightly shorter fertile tillers and leaves than plants with a history of long-term protection.

scholarly journals A Novel Distinct Genetic Variant of Tomato Torrado Virus with Substantially Shorter RNA1-Specific 3’untranslated Region (3’UTR)

Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2454
Author(s):  
Marta Budziszewska ◽  
Przemysław Wieczorek
Keyword(s):  
Amino Acid ◽  
Genetic Variability ◽  
Untranslated Region ◽  
Genetic Variant ◽  
Sequencing Data ◽  
Sequence Analyses ◽  
Nucleotide Substitutions ◽  
Systemic Necrosis ◽  
Single Nucleotide

Tomato torrado virus (ToTV) induces severe systemic necrosis in Solanum lycopersicum. This work aimed at describing the genetic variability of necrosis-inducing ToTV-Wal’17 collected in 2017, derived from the ToTV-Wal’03 after long-term passages in plants. Sequence analyses of the ToTV-Wal’17 indicated twenty-eight single nucleotide substitutions in coding sequence of both RNAs, twelve of which resulted in amino acid changes in viral polyproteins. Moreover the sequencing data revealed that the 3’UTR of ToTV-Wal’17 RNA1 was 394 nts shorter in comparison to Wal’03. The performed sequence analyses revealed that 3’UTR of RNA1 of ToTV-Wal’17 is the most divergent across all previously described European isolates.

scholarly journals Grazing Effects on Snow Accumulation on Rough Fescue Grasslands

2006 ◽  
Vol 59 (4) ◽  
pp. 400-405 ◽  
Author(s):  
Walter D. Willms ◽  
David S. Chanasyk
Keyword(s):  
Snow Accumulation ◽  
Grazing Effects ◽  
Rough Fescue

Effects of Grazing on Abundance and Distribution of Shortgrass Steppe Consumers

2008 ◽  
Author(s):  
Daniel G. Milchunas ◽  
William K. Lauenroth
Keyword(s):  
Plant Communities ◽  
Carbon Allocation ◽  
Ground Surface ◽  
Soil Surface ◽  
Bouteloua Gracilis ◽  
Shortgrass Steppe ◽  
Background Information ◽  
Long Term Effects ◽  
Grazing Effects

Although livestock are the most obvious consumers on the shortgrass steppe, they are certainly not the only consumers. However, livestock may influence the other consumers in a number of different ways. They may directly compete for food resources with other aboveground herbivores. There is behavioral interference between livestock and some species of wildlife (Roberts and Becker, 1982), but not others (Austin and Urness, 1986). The removal of biomass by livestock alters canopy structure (physiognomy) and influences microclimate. Bird, small-mammal, and insect species can be variously sensitive to these structural alterations (Brown, 1973; Cody, 1985; MacArthur, 1965; Morris, 1973; Rosenzweig et al., 1975; Wiens, 1969). There are both short- and long-term effects of grazing on plant community species composition, primary production, and plant tissue quality. Belowground consumers can also be affected by the effects of grazing on soil water infiltration, nutrient cycling, carbon allocation patterns of plants, litter accumulation, and soil temperature. The overall effects of livestock on a particular component of the native fauna can be negative or can be positive through facilitative relationships (Gordon, 1988). In this chapter we assess the effects of cattle grazing on other above- and belowground consumers, on the diversity and relative sensitivity of these groups of organisms, and on their trophic structure. We first present some brief background information on plant communities of the shortgrass steppe and on the long-term grazing treatments in which many of the studies reported herein were conducted. Details on the plant communities are presented by Lauenroth in chapter 5 (this volume), grazing effects on plant communities by Milchunas et al. in chapter 16 (this volume); and grazing effects on nutrient distributions and cycling by Burke et al. in chapter 13 (this volume). The physiognomy of the shortgrass steppe is indicated in its name. The dominant grasses (Bouteloua gracilis and Buchloë dactyloides), forb (Sphaeralcea coccinea), and carex (Carex eleocharis) have the majority of their leaf biomass within 10 cm of the ground surface. A number of less abundant midheight grasses and dwarf shrubs are sparsely interspersed among the short vegetation, but usually much of their biomass is within 25 cm of the g round. Basal cover of vegetation typically totals 25% to 35%, and is greater in long-term grazed than in ungrazed grassland. Bare ground (more frequent on grazed sites) and litter-covered ground (more frequent on ungrazed sites) comprise the remainder of the soil surface (Milchunas et al., 1989).

Short Communication: Estimating abundance, survival and age structure of the Alberes cattle using recapture techniques

2011 ◽  
Vol 91 (3) ◽  
pp. 343-347
Author(s):  
Marta Fina ◽  
Joaquim Casellas ◽  
Jesús Piedrafita
Keyword(s):  
Overall Survival ◽  
Genetic Variability ◽  
Age Structure ◽  
Death Rate ◽  
Short Communication ◽  
Average Length ◽  
Local Breed ◽  
Capture Recapture ◽  
Average Longevity

Fina, M., Casellas, J. and Piedrafita, J. 2011. Short Communication: Estimating abundance, survival and age structure of the Alberes cattle using recapture techniques. Can. J. Anim. Sci. 91: 343–347. The Alberes breed is an endangered bovine breed with an unknown population size. In this study, we estimated a total of 447.9 (435.5 to 456.6) individuals using capture-recapture methods. Overall survival and recapture estimates were 0.85±0.01 and 0.94±0.01, respectively, leading to an average longevity of 5.64 yr and with the highest death rate concentrated in the first 3 yr of life (38.94%). For breeding cows, the average length of the productive life was 8.35 yr. The current population of this local breed is too small to prevent future losses of genetic variability, and a conservation program is essential to ensure the long-term viability of the breed.

scholarly journals Long-Term Grazing Effects on Fescue Grassland Soils

1971 ◽  
Vol 24 (3) ◽  
pp. 185 ◽  
Author(s):  
A. Johnston ◽  
J. F. Dormaar ◽  
S. Smoliak
Keyword(s):  
Grassland Soils ◽  
Grazing Effects

Long-term grazing effects on grassland soil properties in southern British Columbia

2012 ◽  
Vol 92 (4) ◽  
pp. 685-693 ◽  
Author(s):  
C. R. W. Evans ◽  
M. Krzic ◽  
K. Broersma ◽  
D. J. Thompson
Keyword(s):  
British Columbia ◽  
Soil Properties ◽  
Bulk Density ◽  
Aggregate Stability ◽  
Soil Bulk Density ◽  
Mechanical Resistance ◽  
Stocking Rate ◽  
Grassland Soil ◽  
Grazing Effects

Evans, C. R. W., Krzic, M., Broersma, K. and Thompson, D. J. 2012. Long-term grazing effects on grassland soil properties in southern British Columbia. Can. J. Soil Sci. 92: 685–693. Although grazing effects on soil properties have been evaluated on various temperate grasslands, no study has dealt with these effects in the southern interior of British Columbia. The objective of this study was to determine the effects of spring versus fall season grazing as well as grazing [at a moderate rate of 0.6 animal unit months (AUM) ha−1] versus non-grazing by beef cattle on selected soil properties. Effects were determined 20 and 30 yr after the establishment of the field experiment. Soil properties were determined for the 0- to 7.5-cm, 7.5- to 15-cm, and 15- to 30-cm depths. In comparison with fall grazing, spring grazing had greater soil bulk density, greater mechanical resistance within the top 15 cm of the soil profile, higher pH, and lower polysaccharides. This was true for both 20 and 30 yr of treatment. Grazing effects on aggregate stability were observed only after 30 yr with spring grazing leading to a more stable structure with a mean weight diameter (MWD) of 1.5 mm and 32% and 10% of aggregates in the 2- to 6-mm and 1- to 2-mm size fractions, respectively, compared with a MWD of 1.0 mm and 20% and 6% under fall grazing. Greater soil bulk density, mechanical resistance, and pH were observed under the grazed treatment relative to the control without grazing, but as we used a moderate stocking rate the impacts were not as great as in previous studies, which used heavy stocking rates. Our findings show that long-term grazing at a moderate stocking rate of 0.6 AUM ha−1did not have critical detrimental effects on soil properties as some land managers and ranchers have suggested.

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