Rabbit Grazing as the Major Source of Intercanopy Heterogeneity in a Juniper Shrubland

2011 ◽  
Vol 25 (2) ◽  
pp. 176-193 ◽  
Author(s):  
Gábor Markó ◽  
Gábor Ónodi ◽  
Miklós Kertész ◽  
Vilmos Altbäcker
Keyword(s):  
Rabbit Grazing

Factors affecting post-fire seedling establishment of selected mallee understorey species

2000 ◽  
Vol 48 (1) ◽  
pp. 59 ◽  
Author(s):  
J. S. Cohn ◽  
R. A. Bradstock
Keyword(s):  
Large Scale ◽  
Prescribed Burning ◽  
New South ◽  
Eucalyptus Species ◽  
Factors Affecting ◽  
Acacia Species ◽  
Introduced Herbivores ◽  
South Wales ◽  
Rabbit Grazing ◽  
Seedling Germination

Factors affecting the survival of post-fire germinants in mallee communities, in central western New South Wales, were examined. Experiments compared the relative effects of native and introduced herbivores (kangaroos, goats, rabbits), after small- and large-scale fires (20–50 and > 10 000 ha, respectively), with particular emphasis on edge effects, seedling clustering, topography and eucalypt canopy presence. The experiments (1985–1997) focused on common understorey species Acacia rigens Cunn. ex Don, A. wilhelmiana F.Muell. and Triodia scariosa N.T.Burb. subsp. scariosa, in mallee dominated by Eucalyptus species. Following a large fire (1985), high spring rainfall and rabbit grazing on A. rigens only, survival of Acacia species and T. scariosa remained relatively high 4 years later (60–70%). After small burns (1987, 1988), low spring rainfall and grazing by rabbits and kangaroos, survival of Acacia species declined to between 0 and 30% of the germinants by the second summer. In most cases, local extinction had occurred within 8 years. After small burns (1988, 1989) and low spring rainfall, the survival of T. scariosa declined to between 0 and 35% of germinants by the second summer (effect of grazing unknown). No consistent effect of edge, topography and eucalypt canopy was found. Survival of clustered Acacia seedlings was between 10 and 20% lower than unclustered seedlings. Given the high frequency of low rainfall and its interaction with grazing, prescribed burning of mallee for wildfire control and nature conservation may require the local elimination of rabbits and a reduction in kangaroo numbers, especially in the first spring and summer following seedling germination.

Effects of disturbance and rabbit grazing on seedling recruitment of six mesic grassland species

1999 ◽  
Vol 9 (2) ◽  
pp. 145-156 ◽  
Author(s):  
Grant R. Edwards ◽  
Michael J. Crawley
Keyword(s):  
Seedling Recruitment ◽  
Plantago Lanceolata ◽  
Plant Cover ◽  
Seedling Emergence ◽  
Soil Disturbance ◽  
Seedling Mortality ◽  
Grassland Species ◽  
Rabbit Grazing ◽  
Plant Densities ◽  
Seed Sowing

AbstractSeeds of two grass (Arrhenatherum elatius and Festuca rubra), two herb (Plantago lanceolata and Rumex acetosa) and two legume (Lotus corniculatus and Trifolium repens) species were sown in summer 1995 at four densities (no seed, 1000, 10 000 and 50 000 seeds m−2) into an established rabbit-grazed grassland given factorial combinations of rabbit fencing (with and without fences) and soil disturbance (with and without cultivation). On plots where no seeds were sown, only the species with persistent seed banks (P. lanceolata, L. corniculatus and T. repens) showed enhanced seedling emergence in response to disturbance. In disturbed soil, seedling densities of all species increased with increasing density of sown seeds, the effects of which were still evident for plant cover 2 years after seed sowing. In undisturbed vegetation, A. elatius, F. rubra, P. lanceolata and R. acetosa showed increased seedling densities following seed sowing; but in each case, there was an upper asymptote to seedling recruitment, presumably due to microsite limitation. Rabbit grazing reduced seedling densities, with this reduction being more pronounced with disturbance than without. However, the effect of rabbit grazing did not persist for some species; seedling mortality of R. acetosa, P. lanceolata, L. corniculatus and T. repens was higher on plots without rabbit grazing, so that plant densities of these species in summer 1996 and plant cover in summer 1997 were greater on grazed plots. The results indicate interactions between soil disturbance, propagule availability and herbivory, rather than disturbance alone, will play an important role in controlling seedling recruitment and species habitat distributions in grasslands.

Regeneration of Three Tree Species in Arid South-Eastern Australia

1985 ◽  
Vol 33 (6) ◽  
pp. 715 ◽  
Author(s):  
CJ Chesterfield ◽  
RF Parsons
Keyword(s):  
Nature Conservation ◽  
Tree Species ◽  
Arid Zone ◽  
Tree Seedlings ◽  
Seedling Regeneration ◽  
Mammalian Herbivores ◽  
Eastern Australia ◽  
Rabbit Grazing ◽  
A Site

Grazing effects by introduced mammals on tree seedlings in the arid zone have caused concern for the long-term future of some tree species. This was investigated by measuring stem girths of Casuarina cristata Miq., Heterodendrum oleifoliurn Desf. and Myoporum platycarpum R.Br. in arid-zone wood- lands. Episodic seedling regeneration of Myoporum is inferred following series of wet years in the 1950s and 1970s. Although young Myoporum plants appear unpalatable to stock, regeneration may be sup- pressed by rabbit-grazing in some areas. Almost no Heterodendrurn seedlings were found but suckering was common after burning and clearing. This species is highly palatable to grazing mammals and suckers may grow to safety above the browse line only where stock are absent. Evidence for recent Casuarina seedling regeneration was limited to one cohort, on a site that had been flooded. While suckers can be found locally where surface roots become exposed, suckering appears insufficient to perpetuate many Casuarina stands. Mammal-grazing seems important in strongly limiting regeneration. While Casuarina and Heterodendrum stand densities decline due to natural senescence and occasional fire, the only species regenerating into gaps is Myoporum. There is concern for the future of Casuarina and Heterodendrum, given their widespread failure to regenerate despite the wettest 3 years ever recorded, in 1973-75. On pastoral land, at least 10 years without stock-grazing might be needed for successful regeneration of Heterodendrurn. In reserves, some nature conservation programs for woodlands might require virtual eradication of all exotic mammalian herbivores, including goats.

Response of Vegetation on Subantarctic Macquarie Island to Reduced Rabbit Grazing

1998 ◽  
Vol 46 (1) ◽  
pp. 15 ◽  
Author(s):  
Geof Copson ◽  
Jennie Whinam
Keyword(s):  
Relative Abundance ◽  
Vascular Plant ◽  
Control Program ◽  
Initial Response ◽  
Grazing Pressure ◽  
The Other ◽  
Macquarie Island ◽  
Rabbit Grazing ◽  
Luxuriant Growth ◽  
Study Sites

The responses of vascular plant species to a reduction in grazing pressure were monitored as part of a rabbit-control program on Macquarie Island. The initial response of the vegetation was more luxuriant growth with changes in abundance recorded after 2–3 years. After 8–10 years the relative abundance of several species had changed while species not previously recorded had appeared on study sites and others had disappeared. Of the 32 species recorded on study sites, 11 species (Agrostis magellanica, Deschampsia chapmanii, Festuca contracta, Juncus scheuchzerioides, Luzula crinita, Pleurophyllum hookeri, Poa annua, P. foliosa, Stilbocarpa polaris and Uncinia spp. (two species)) were found to form the major portion of the rabbits’ diet while another four species (Acaena magellanica, Cerastium fontanum, Isolepis aucklandica, Polystichum vestitum) were moderately grazed. The other species were either rarely grazed or occurred too infrequently to assess. Of the 25 species that were recorded over 30 times, 17 were considered to have benefited from the introduction of rabbits.

The grazing of British sand dune vegetation

1989 ◽  
Vol 96 ◽  
pp. 75-88
Author(s):  
Laurence A. Boorman
Keyword(s):  
Species Diversity ◽  
Sand Dunes ◽  
Plant Competition ◽  
Grazing Management ◽  
Similar Proportion ◽  
Dune Vegetation ◽  
Rabbit Grazing ◽  
Dune Grassland ◽  
Grazing Intensities ◽  
Dune Heath

SynopsisThe herbaceous vegetation of sand dunes is quite strongly influenced by a number of different grazing animals, principally vertebrates. Between 1985 and 1987 forty-eight dune sites were visited and studied, information being recorded on the vegetation and grazing status of 777 quadrats.The results of the survey confirm that the dominant grazing animal in British sand dunes is the rabbit. Over 70% of the quadrats are regarded as being rabbit-grazed directly and over 98% of the dune sites sampled appeared to be affected by rabbit grazing to some extent. Just over a third of the sites were grazed by cattle and a similar proportion by sheep; generally it was either cattle or sheep although five sites were grazed by both. There was only one site significantly grazed by ponies although a number of other sites were grazed occasionally by passing ponies.The intensity of grazing was very variable. Out of the forty-eight sites, three were regarded as being ungrazed and a further ten only lightly grazed, while nine sites were considered to be heavily grazed. However the remaining twenty-six sites were recognised as being intermediate only to the extent of not being obviously overgrazed or undergrazed. It was further recognised that the present state of the vegetation tended to reflect the grazing management in the recent past rather than current practice. A change in the grazing management often took many years to effect a permanent change in the vegetation.The grazing requirements to promote species diversity are very different for the different habitat types. In the yellow dunes the plant community is open with bare ground for colonisation and plant competition is not intense. There is thus little need for the control of plant growth by grazing.Dune grassland, in the narrow sense, needs to be grazed to maintain plant species diversity. The purpose of grazing is to remove prolific growth from the most vigorously growing plants to reduce competition. Lower grazing intensities are needed for all the year round grazing than when grazing is first applied to an area or is a permanent measure for limited periods of the year only.Dune slacks are generally best grazed by cattle and, with the higher soil moisture, grazing intensities can be higher than those applied to dune grassland. Excessive grazing is likely to cause serious damage to both the soil and the vegetation, especially in the wetter areas.Dune heath vegetation has a low productivity and its own special management problems. It needs to be grazed (or cut or burnt) to maintain the internal mosaic by the successful regeneration of the main species, but too much grazing will lead to conversion to a species-poor acid grassland.

Effects of Rabbit Grazing on Population Variables of Chorthippus brunneus (Orthoptera)

Oikos ◽  
1985 ◽  
Vol 44 (1) ◽  
pp. 27 ◽  
Author(s):  
F. W. L. Grayson ◽  
Mark Hassall
Keyword(s):  
Rabbit Grazing

The Effects of Rabbit Grazing on the Grasslands of Macquarie Island

1960 ◽  
Vol 48 (3) ◽  
pp. 729 ◽  
Author(s):  
A. B. Costin ◽  
D. M. Moore
Keyword(s):  
Macquarie Island ◽  
Rabbit Grazing

Barking up the wrong tree? Are livestock or rabbits the greater threat to rangeland biodiversity in southern Australia?

2016 ◽  
Vol 38 (6) ◽  
pp. 523 ◽  
Author(s):  
G. Mutze
Keyword(s):  
Confounding Factor ◽  
Biodiversity Loss ◽  
Grazing Pressure ◽  
Livestock Grazing ◽  
Grazing Impact ◽  
Plant Biodiversity ◽  
Remote Areas ◽  
Rabbit Grazing ◽  
European Rabbits ◽  
Buy Back

Increasing provision of permanent water points has put most Australian pastoral rangelands within grazing distance of sheep, cattle, kangaroos and large feral herbivores, and there is concern that grazing-sensitive native plants will be lost as a result. Proposals have been developed to conserve plant biodiversity by permanently excluding livestock from any areas that are remote from permanent water, or to buy back pastoral properties and remove existing water points to create large reserves. There is, however, little evidence that water-remote areas provide refuge for grazing-sensitive plants, nor consistent evidence of plant biodiversity loss along gradients of increasing livestock grazing pressure in proximity to water. One of the reasons why that evidence might be lacking is that most livestock studies have not considered the grazing impact of sympatric European rabbits, the most widespread and abundant wild herbivore in southern Australia. Numerous studies have shown that rabbit grazing has a major impact on rangeland vegetation and can prevent regeneration at densities which may be too low to be thought important. Plant biodiversity gradients are readily discernible along gradients of rabbit density in livestock-free reserves. Rabbits are therefore likely to be a significant confounding factor when assessing livestock impacts, or possibly the primary cause of observed patterns of plant diversity. If so, attempts to preserve plant biodiversity by removing livestock are destined to fail in rabbit-grazed areas. Public funds for biodiversity conservation in the pastoral zone might be better spent on co-investment with pastoralists for rabbit control on conservatively stocked properties, rather than on restricting pastoral use of land in livestock-free, rabbit-infested reserves.

The Response of Rabbit Populations and Vegetation to Rabbit Control on a Calcareous Shrubby Grassland in Central Australia

1985 ◽  
Vol 12 (2) ◽  
pp. 237 ◽  
Author(s):  
BD Foran ◽  
WA Low ◽  
BW Strong
Keyword(s):  
Seasonal Changes ◽  
Substantial Improvement ◽  
European Rabbit ◽  
Control Methods ◽  
Vegetation Composition ◽  
Experimental Control ◽  
Rabbit Grazing ◽  
Central Australia ◽  
Highly Correlated ◽  
Previous Summer

The effect of rabbit control methods on rabbit populations and subsequent changes in vegetation were assessed over 2 years on a calcareous shrubby grassland in central Australia. Warren ripping and fumigating decreased mean population levels to four rabbits per kilometre of spotlight transect, and 1080 poisoning decreased mean levels to 9 km-1, compared to the untreated levels of 20 km-l. Release of European rabbit fleas did not have any significant effect on rabbit populations. In the untreated rabbit populations, 68% of the fluctuation in numbers was accounted for by total rainfalls in the previous summer and the previous winter, and by a forage greenness rating. Experimental control of rabbits combined with exclosures indicated that grazing by high numbers of rabbits reduced the frequency of Enneapogon spp. at one site whereas levels rose in all other sites during the two years of good rainfall. The frequency of several species, such as Chenopodium cristatum, Phyllanthus rhytidospermus and Portulaca oleracea, was highly correlated with rabbit density in the previous year, suggesting that rabbit grazing promotes their increase. Grazing'by rabbits alone depressed standing biomass in the following season by 300 kg ha-1 from a maximum 1200 kg ha-1 within the exclosures. Cattle grazing further decreased biomass by 150 kg ha-1. Seedlings of Acacia kempeana were almost absent in those areas open to rabbit grazing, but they were reasonably dense where rabbits were excluded. However, the vegetation response over the 2 years of experiment was due mainly to seasonal changes rather than rabbit control, and does not justify the expense of rabbit control at this stage. Substantial improvement in vegetation composition over the longer term may alter this conclusion.

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