Long-Term Heavy-Grazing Effects on Soil and Vegetation in the Four Corners Region

1990 ◽  
Vol 35 (1) ◽  
pp. 9 ◽  
Author(s):  
Apollo B. Orodho ◽  
M. J. Trlica ◽  
C. D. Bonham
Keyword(s):  
Grazing Effects ◽  
Heavy Grazing ◽  
Four Corners

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).

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.

Managing for rainfall variability: impacts of grazing strategies on perennial grass dynamics in a dry tropical savanna

2011 ◽  
Vol 33 (2) ◽  
pp. 209 ◽  
Author(s):  
D. M. Orr ◽  
P. J. O'Reagain
Keyword(s):  
Carrying Capacity ◽  
Rainfall Variability ◽  
Perennial Grasses ◽  
Heteropogon Contortus ◽  
Heavy Grazing ◽  
Average Rainfall ◽  
Sustainable Grazing ◽  
Grazing Strategies ◽  
The Impact

Rainfall variability remains a major challenge to sustainable grazing management in northern Australia with perennial grasses the key to the stability of the resources that maintain a sustainable grazing industry. This paper describes the dynamics of five perennial grasses – Bothriochloa ewartiana (Domin) C.E. Hubb., Chrysopogon fallax S.T. Blake, Aristida spp., Panicum effusum R. Br. and Heteropogon contortus (L.) P. Beauv. ex Roem. & Schult. in relation to three grazing strategies – moderate stocking at long-term carrying capacity, heavy stocking and rotational wet season spelling. The research was conducted in permanent quadrats on the predominant land type in an extensive grazing study in an Aristida-Bothriochloa pasture in north Australia between 1998 and 2010. Summer rainfall was above average for two periods – 1998 – 2001 and 2008 – 2010 with drought and below-average rainfall from 2002 to 2007. Low rainfall affected the dynamics of all grasses by reducing survival and basal area through its effect on plant size; this impact was most noticeable for the shorter-lived Aristida spp., P. effusum and H. contortus. The impact of grazing was greatest on the long-lived B. ewartiana and C. fallax; this effect was accentuated by the 2002–07 drought. Heavy grazing during this period further reduced the survival and size of B. ewartiana in comparison with the moderate stocking and rotational spell treatments. In contrast, the survival of C. fallax was reduced in the moderate stocking and rotational spelling treatment during drought, relative to that under heavy grazing. The density of B. ewartiana declined even under moderate grazing and despite two sequences of above-average rainfall because seedling recruitment failed to offset mature plant death. Results from this study emphasised the importance of maintaining the existing populations of key long-lived species such as B. ewartiana through good management. These results also supported the overall findings from the grazing study indicating that stocking at the long-term carrying capacity is sustainable in managing for climate variability.

Long-term grazing effects on soil-atmosphere exchanges of CO2, CH4 and N2O at different grasslands in Inner Mongolia: A soil core study

2019 ◽  
Vol 105 ◽  
pp. 316-328 ◽  
Author(s):  
Weiwei Chen ◽  
Xunhua Zheng ◽  
Benjamin Wolf ◽  
Zhisheng Yao ◽  
Chunyan Liu ◽  
...  
Keyword(s):  
Inner Mongolia ◽  
Soil Core ◽  
Grazing Effects ◽  
Soil Atmosphere ◽  
Core Study ◽  
Ch4 And N2o

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

Plant Spread Dynamics and Spatial Patterns in Forest Ecology

2004 ◽  
Author(s):  
Sergio A. Cannas ◽  
Diana E. Marco
Keyword(s):  
Public Health ◽  
Biological Invasions ◽  
Exotic Species ◽  
Native Species ◽  
Forest Ecology ◽  
Soil Composition ◽  
Heavy Grazing ◽  
Spread Dynamics ◽  
Strong Disturbance

Species in an ecosystem can be classified as natives or exotics. Native species are those that have coevolved in the ecosystem, while exotic ones have not. The introduction of exotic species into an ecosystem is usually associated with human influence, which can be intentional or accidental. Some exotic species do not survive, at least not without artificial assistance. But some others do quite well on their own in a new environment. Exotic species may have no natural predators in the new environment or they may make better use of the natural resources than the natives, so they spread in the new territory and compete with some of the natives, who eventually become extinct. Exotic species that successfully establish and spread in an ecosystem are called invaders. The process by which an invader arrives and spreads into the new territory is called biological invasion. It is worth mentioning that, although invaders are usually exotic species, sometimes native species may also behave like invaders. That is, if an ecosystem suffers a strong disturbance, like fire or heavy grazing, some native species whose populations were originally stable may start to grow, outcompeting other native species. There are many examples of introduced species that became invaders, ranging from bacteria to cattle. Accidental or intentional introductions by humans are responsible for most of the present biological invasions, threatening the structure and functioning of many ecosystems. There are many effects associated with biological invasions, perhaps the most important one being the possible loss of biodiversity in the long term. But biological invasions may also introduce changes in different environmental traits, like climate, hydrology (invaders may consume more water than natives), and soil composition (for instance, some plants take up salt from soil and deposit it on the surface, making it unsuitable for some native species). All these changes have strong economical impacts, considering their influences in agriculture, forestry, and public health [9]. Hence, it is of interest to understand this phenomenon in order to predict the potential invasiveness of a species before its introduction in an ecosystem, and to develop strategies of control for invasive species that have already been introduced.

scholarly journals Long-Term Grazing Effects on Stipa-Bouteloua Prairie Soils

1972 ◽  
Vol 25 (4) ◽  
pp. 246 ◽  
Author(s):  
S. Smoliak ◽  
J. F. Dormaar ◽  
A. Johnston
Keyword(s):  
Prairie Soils ◽  
Grazing Effects
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