Rapid conservation evidence for the impact of sheep grazing on a threatened digger wasp

The health and production of sheep grazing perennial ryegrass with and without wild-type endophyte (Neotyphodium lolii) has been studied in several trials over a number of years. Lambs/ hoggets grazing predominantly perennial ryegrass swards with endophyte developed moderate to severe ryegrass staggers in summer and autumn, while those grazing endophyte-free ryegrass did not. Lambs/hoggets grazing ryegrass with endophyte also had more dags, lower growth rates, lower plasma prolactin levels, higher body temperatures and respiration rates under warm humid conditions. Most of these adverse responses were more severe in summer and autumn when endophyte toxin concentrations were highest. Many of these symptoms are similar to those described for the "autumn ill thrift" syndrome in New Zealand. Keywords: dags, endophyte, flystrike, growth rates, hyperthermia, Neotyphodium, perennial ryegrass, prolactin, ryegrass staggers, sheep

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The impact of sheep grazing on the depth of spider burrows and of burrows selected by the pygmy bluetongue lizard (Tiliqua adelaidensis)

Wildlife Research ◽

10.1071/wr16138 ◽

2016 ◽

Vol 43 (8) ◽

pp. 691 ◽

Cited By ~ 4

Author(s):

Jessica Clayton ◽

Michael Bull

Keyword(s):

Endangered Species ◽

South Australia ◽

Sheep Grazing ◽

Vegetative Cover ◽

Austral Spring ◽

Essential Component ◽

Grazing Sheep ◽

Essential Resource ◽

The Impact ◽

Domestic Stock

Context Grazing by domestic stock can potentially influence ecosystems positively or negatively, depending on the grazing regime and intensity. The pygmy bluetongue lizard (Tiliqua adelaidensis) is an endangered species, restricted to fragmented grasslands in the Mid North region of South Australia, predominantly grazed by sheep. These lizards refuge in vertical burrows. They do not dig their own burrows, instead relying on co-existing spiders for this essential resource. Aims We investigated how sheep grazing influenced spider burrows, and predicted the following: that grazing sheep might trample and destroy shallow burrows; that burrows in grazed habitat with less vegetative cover would have higher temperatures in summer; and that, by way of compensation, spiders would dig deeper burrows in grazed habitat. Methods We monitored 12 30m×30m plots monthly, over two austral spring/summer periods (September–March 2012–14). We recorded the number, depth and occupant of all spider burrows in those plots in each survey. We also measured temperatures inside artificial burrows in grazed and ungrazed habitat over a 3-day period in September 2014. Key results Mean burrow depth increased with grazing. This was not because individual burrows became deeper, but because the shallowest burrows were lost where there were sheep. Burrows were significantly hotter in grazed habitat, but lizards consistently chose deeper, cooler burrows. In the subset of burrows that were occupied by lizards, there was no difference in depth between grazed and ungrazed treatments. We detected no difference in spider digging activity between grazed and ungrazed plots. Conclusions Sheep grazing can destroy shallow burrows, probably through trampling, and because sheep produce burrow filling debris. However, grazing did not affect deeper burrows occupied by pygmy bluetongue lizards. Implications This short study indicated that moderate levels of grazing have low impact on deeper burrows suitable for pygmy bluetongue lizards and for lizard persistence. It explains how sheep and lizards have co-occurred for so long, but leaves open the question of how the loss of shallow burrows affects populations of the burrow-digging spiders that are an essential component of the lizard environment.

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Evaluation of Alfalfa Weevil (Coleoptera: Curculionidae) Densities and Regrowth Characteristics of Alfalfa Grazed by Sheep in Winter and Spring

Journal of Entomological Science ◽

10.18474/0749-8004-39.4.598 ◽

2004 ◽

Vol 39 (4) ◽

pp. 598-610 ◽

Cited By ~ 3

Author(s):

Hayes B. Goosey ◽

Patrick G. Hatfield ◽

Sue L. Blodgett ◽

S. Dennis Cash

Keyword(s):

Crude Protein ◽

Forage Yield ◽

Sheep Grazing ◽

Alfalfa Weevil ◽

Nutrient Quality ◽

Hypera Postica ◽

Medicago Sativa L ◽

The Impact ◽

Neutral Detergent Fibers ◽

Crop Health

Fall regrowth of alfalfa, Medicago sativa (L.), serves as a major source of winter pasture for Montana sheep producers. In years of drought, alfalfa fields are extensively winter/spring grazed; however, the impact on crop health is unknown. Alfalfa paddocks were continuously grazed for 95 d in 2002 and 98 d in 2003 during winter and spring to determine the impact on spring and summer alfalfa regrowth, nutrient quality characteristics, and alfalfa weevil, Hypera postica Gyllenhal, densities. Grazed and non-grazed forage yield, crude protein (%), and acid and neutral detergent fibers (%) did not differ at harvest (P> 0.17) during either study year. Acid and neutral detergent fibers (kg/ha) were greater (P < 0.05) in non-grazed compared to grazed plots during 2002–2003. Alfalfa weevil densities were lower in grazed than non-grazed plots (P< 0.03) over four sampling dates during both study years. Winter/spring sheep grazing appears to offer potential for alfalfa weevil management without compromising yield or nutritive factors of subsequent alfalfa production.

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The impact of intensive sheep grazing in the spring on the vegetation of xerothermic grasslands in Stawska Góra nature reserve

Ecological Questions ◽

10.12775/eq.2016.004 ◽

2016 ◽

Vol 23 ◽

pp. 43 ◽

Cited By ~ 1

Author(s):

Marianna Warda ◽

Mariusz Kulik ◽

Tomasz Gruszecki

Keyword(s):

Nature Reserve ◽

Sheep Grazing ◽

The Impact

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Effect of inbreeding on growth of white clover

NZGA: Research and Practice Series ◽

10.33584/rps.12.2006.3026 ◽

2006 ◽

Vol 12 ◽

pp. 131-134

Author(s):

Greig Cousins ◽

Derek Woodfield

Keyword(s):

Inbreeding Depression ◽

White Clover ◽

Yield Reduction ◽

Breeding Strategies ◽

S Locus ◽

Sheep Grazing ◽

Herbage Yield ◽

Population Improvement ◽

The Impact ◽

Future Population

Determining the impact of inbreeding on white clover growth will assist in determining the optimal breeding strategies for future population improvement. A dominant self-fertility allele (Sf) at the S locus was used to inbreed white clover to nearhomozygosity (F=0.99). Inbreeding depression was higher in the glasshouse experiment than was observed under sheep grazing in the field. It was also higher for comparable generations with a 54% reduction in herbage yield of the S1 generation in the glasshouse compared with 29% yield reduction under grazing. The level of inbreeding depression for herbage yield of the S1 and S2 generations observed in the glasshouse were consistent with the theoretical reduction in yield. However in later generations the actual herbage yield was consistently higher than expected. This may be due to heterozygosity being maintained during inbreeding or to the elimination of weaker individuals under higher competition and grazing experienced under field conditions. The degree to which inbreeding depression is overcome by outcrossing (heterosis) in white clover will determine whether hybrids or semi-hybrid cultivars can be successfully developed

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An experimental study of the impact of seasonal sheep grazing on formerly fertilized grassland

Journal of Vegetation Science ◽

10.2307/3236302 ◽

1996 ◽

Vol 7 (4) ◽

pp. 535-542 ◽

Cited By ~ 13

Author(s):

Trudy A. Watt ◽

Joanna R. Treweek ◽

Fiona S. Woolmer

Keyword(s):

Experimental Study ◽

Sheep Grazing ◽

The Impact

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The impact of sheep grazing on the fecundity and timing of reproduction in the endangered pygmy bluetongue lizard, Tiliqua adelaidensis

Amphibia-Reptilia ◽

10.1163/15685381-00003119 ◽

2017 ◽

Vol 38 (4) ◽

pp. 401-409 ◽

Cited By ~ 1

Author(s):

Torben P. Nielsen ◽

C. Michael Bull

Keyword(s):

Endangered Species ◽

Reproductive Output ◽

Sheep Grazing ◽

Timing Of Reproduction ◽

Successful Reproduction ◽

Native Grassland ◽

The Future ◽

Live Stock ◽

The Impact ◽

Future Management

The endangered pygmy bluetongue lizard (Tiliqua adelaidensis) is found only in a few remaining patches of South Australian native grassland, most of which are used for live stock grazing. The lizards occupy spider burrows, they mate in October-November and females produce litters of one to four live born neonates in mid-January-mid-March. In this study we use ultrasound scans of females and observations of neonates in their maternal burrows to investigate how grazing affects the fecundity of the pygmy bluetongue lizard. We predicted that lizards in moderately grazed paddocks would have a higher reproductive output than lizards in hard grazed paddocks. Ultrasound scans indicated that this hypothesis was correct by showing a higher mean number of yolk sacs in females from moderately than from hard grazed paddocks. Females from moderately grazed paddocks also gave birth significantly earlier than females in hard grazed paddocks. The higher number of yolk sacs did not result in a significantly higher number of neonates observed in the burrows, which indicates that the weekly burrow observations used in this study may underestimate true fecundity. Understanding how grazing affects the fecundity of the pygmy bluetongue lizard is essential to the future management of this endangered species. This is not only because grazing is used to manage the habitat of all currently known lizard populations, but also because successful reproduction will be needed in those populations to supply the “surplus” individuals predicted to be essential for relocation programs to ensure the survival of the species.

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Increased grazing drives homogenisation but reduced grazing increases turnover in upland habitat mosaics

Biodiversity and Conservation ◽

10.1007/s10531-021-02305-5 ◽

2021 ◽

Author(s):

Robin J. Pakeman ◽

Debbie A. Fielding

Keyword(s):

Large Scale ◽

Grazing Intensity ◽

Sheep Grazing ◽

Species Replacement ◽

Habitat Mosaics ◽

Trade Offs ◽

Set Up ◽

Original Species ◽

The Impact

AbstractMany ecosystems are grazed by livestock or large, wild herbivores and exist as mosaics of different vegetation communities. Changing grazing could have an impact on heterogeneity as well as on composition. A long-term, large-scale grazing experiment that maintained existing low-intensity sheep grazing, tripled it, removed it and partially substituted sheep grazing by cattle grazing was set up on a mosaic of upland vegetation types. The impact of changing grazing regimes was assessed in terms of changes in temporal and spatial species and functional beta diversity. Removal of grazing had the highest impact on species replacement, whilst increased grazing was closest to maintaining the original species complement. Wet heath and Molina mire had the lowest turnover, but wet heath showed the highest changes in unidirectional abundance as it contained species capable of increasing in abundance in response to changing grazing intensity. Agrostis-Festuca and Nardus grasslands displayed the highest level of balanced species replacement reflecting their more dynamic vegetation. In functional terms, there was no clear separation of communities based on their grazing preference, all were relatively resistant to change but Nardus grassland was the most resistant to the removal of grazing. The increased offtake associated with increased grazing led to a degree of homogenisation as grazing tolerant species associated with preferred communities increased in the unpreferred ones. Decisions about grazing management of the uplands involve many trade-offs, and this study identified potential trade-offs between stability and homogenisation to add to existing ones on the biodiversity of different groups of species and on ecosystem services.

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