Responses of calcareous grassland plant communities to changed seasonal grazing management: results of a 31 year study

2021 ◽  
pp. 126026
Author(s):  
Lucy E. Ridding ◽  
James M. Bullock ◽  
Kevin J. Walker ◽  
Clive Bealey ◽  
Richard F. Pywell
2010 ◽  
Vol 32 (4) ◽  
pp. 379 ◽  
Author(s):  
Lewis P. Kahn ◽  
Judi M. Earl ◽  
Millie Nicholls

Research was conducted in the mid-north of South Australia over the period 2000–05 to evaluate the effects of different grazing management cues on composition and production of a grassland. The management cues were based on calendar, plant phenology or herbage mass thresholds using grazing exclusion as a control. There were five grazing treatments: (i) regional practice (RP), where sheep grazed continuously for the period April–December; (ii) autumn rest, where sheep grazing was restricted to June–December; (iii) spring rest, where sheep grazing was restricted to April–August; (iv) high density and short duration (HDSD), where herbage mass thresholds determined when grazing occurred and for what duration; and (v) nil (NIL) grazing by domestic herbivores. Mean annual estimates of herbage mass were highest for NIL and HDSD and inclusion of the estimate of herbage consumption by sheep resulted in greatest primary plant production in HDSD. The contribution of perennial grasses to herbage mass declined with RP and seasonal grazing treatments. Frequency of perennial grasses was unaffected by grazing treatment but the number of perennial grass plants increased over time in RP and seasonal treatments. HDSD allowed maintenance of basal cover whereas bare ground increased with RP and seasonal treatments. Litter accumulated in NIL but this was associated with a decline in perennial basal cover. Seasonal grazing treatments did not provide an advantage over RP and there appeared to be no benefit from including phenology in management decisions. In contrast, HDSD resulted in a stable and productive grassland ecosystem, with stocking rate estimated at 78% greater than other treatments. These features offer a desirable mix for future industry adoption in the mid-north of South Australia.


2019 ◽  
Author(s):  
Zhen Wang ◽  
Xiuli Wan ◽  
Mei Tian ◽  
Xiaoyan Wang ◽  
Junbo Chen ◽  
...  

Abstract. Grassland covers more than a third of the earth's terrestrial surface. Grazing management can affect grassland carbon dynamics and soil microbial biomass, yet limited information is available on the effects of grassland management on carbon dioxide efflux and soil microbial biomass carbon (SMBC) and nitrogen (SMBN). During 2010 and 2011, soil respiration (Rs), SMBC, and SMBN, as well as different abiotic and biotic factors were measured after long term rotational grazing (nine years) on the grasslands of the semi-arid Loess Plateau, China. Grazing management included different grazing intensities and seasonal grazing patterns (in summer or winter). Stocking rates of 0, 2.7, 5.6, and 8.7 sheep ha−1 were used as grazing intensities, and warm-season grazing and cold-season grazing by sheep during summer and winter from 2010 to 2011 were used as grazing patterns. We hypothesized that the different seasonal grazing patterns and grazing intensities would affect Rs in a semi-arid grassland ecosystem. Our results indicated that grazing management significantly affected the rate of Rs, which supports our hypothesis. Grazing intensities tended to increase SMBC, but had no effect on SMBN. We also found that SMBC in cold season grazing plots was higher than that in the warm season grazing plots. However, variation in grazing patterns had little effect on SMBN. Furthermore, a structural equation model indicated that the aboveground biomass and soil microbial biomass were two important biotic factors that controlled Rs. Soil temperature (ST) and soil moisture (SM), which were affected by grazing intensity and patterns, were significant abiotic factors affecting Rs and soil microbial biomass. Our observations suggest that grazing management may change soil carbon sequestration rates in grassland ecosystems, because of changes in the aboveground plant and soil microbial biomass.


2005 ◽  
Vol 2005 ◽  
pp. 244-244
Author(s):  
J. R. B. Tallowin ◽  
A. J. Rook ◽  
S. M. Rutter

Grazing is a natural process affecting the composition and structure of plant communities and is widely considered to be an essential nature conservation tool. However, our understanding of the interrelations between grazing by large herbivores and biodiversity is relatively poor. Nature conservation imperatives, to control succession, for example, mean that practice has moved ahead of the science knowledge base on grazing. This gap now needs to be bridged. Improving our understanding of and ability to predict consequences of manipulating grazing pressure, duration, type and/or mix of large herbivore on biodiversity outcomes are particular issues that we are addressing.


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