Effects of wildlife grazing on the production, ground cover and plant species composition of an established perennial pasture in the Midlands region, Tasmania
Rowan W. Smith A E , Mick Statham A , Tony W. Norton B , Richard P. Rawnsley C , Helen L. Statham A , Alistair J. Gracie D and Daniel J. Donaghy CA Extensive Agriculture Centre, Tasmanian Institute of Agricultural Research, PO Box 46, Kings Meadows, Tas. 7249, Australia.
B Extensive Agriculture Centre, Tasmanian Institute of Agricultural Research, PO Box 3523, Burnie, Tas. 7320, Australia.
C Dairy Centre, Tasmanian Institute of Agricultural Research, PO Box 3523, Burnie, Tas. 7320, Australia.
D School of Agricultural Science, University of Tasmania, Private Bag 54, Hobart, Tas. 7001, Australia.
E Corresponding author. Email: smithro@utas.edu.au
Wildlife Research 39(2) 123-136 https://doi.org/10.1071/WR11032
Submitted: 14 February 2011 Accepted: 3 December 2011 Published: 26 March 2012
Abstract
Context: Management of grazing wildlife on private land in Tasmania is a contentious issue for landowners, animal-welfare groups and the Tasmanian Government. Wildlife species known to graze pasture include Tasmanian pademelon (Thylogale billardierii), Bennett’s wallaby (Macropus rufogriseus rufogriseus), forester kangaroo (Macropus giganteus), brushtail possum (Trichosurus vulpecula) and fallow deer (Dama dama). Understanding the spatio-temporal patterns of wildlife grazing is important when considering wildlife-control options to mitigate pasture loss; however, limited research has been undertaken.
Aims: To quantify the impact of wildlife grazing on pasture production and to assess the spatial and temporal pasture biomass loss from an established pasture; to investigate the effect of protecting pastures from wildlife grazing on species composition of an existing perennial pasture; to determine whether wildlife grazing contributes to a decline in the composition of improved pasture species over time and an increase in-ground cover of less desirable grasses and broadleaf weeds; and to examine whether protecting pastures from wildlife grazing could increase ground cover.
Methods: Pasture biomass loss to wildlife grazing was determined by a paired exclusion-cage method over a 26-month period from February 2008 to April 2010. A quantitative pasture model was used to simulate pasture growth at the study site. Changes in the botanical composition of the sward in response to wildlife grazing were determined by hand-separation, drying and weighing of harvested material, and also by visual estimation of the ground cover of individual plant species. A wildlife faecal-pellet survey was used to develop an index of wildlife feeding activity.
Key results: Pasture loss to wildlife grazing varied spatially and temporally. Pasture loss decreased with increasing distance from the edge of cover vegetation. The proportion of pasture lost increased during periods of slow pasture growth. Visual estimates of ground cover showed that grazing by wildlife resulted in an increase in bare ground in unprotected swards, whereas protection from grazing resulted in an increase in production of perennial and annual species, as determined by hand-separation of harvested material, and a decrease in bare ground as determined by visual estimate. Faecal-pellet surveys were found to be strongly correlated with pasture biomass losses.
Conclusions: The proportion of pasture loss to wildlife grazing was found to be influenced by distance from native vegetation and also by pasture availability, which was seasonal. Wildlife can alter the composition of pastures by reducing the ground cover and yield of improved grasses. Continual grazing of pastures by wildlife in addition to rotational sheep grazing may increase the amount of bare ground.
Implications: Wildlife-control methods need to be carefully chosen if the intended benefits of alleviating pasture biomass losses are to be achieved. Quantifying the loss of pasture is important because it enables the extent and significance of losses to be determined and may inform decisions about the most appropriate wildlife control measures to adopt. Controlling wildlife during periods of slow pasture growth may be important in preventing damage and yield loss of plant species actively growing during these times. Failure to control wildlife may result in a decrease in the composition of desirable plant species.
References
Arnold, G. W., Steven, D. E., and Weeldenburg, J. R. (1989). The use of surrounding farmland by western grey kangaroos living in a remnant of wandoo woodland and their impact on crop production. Australian Wildlife Research 16, 85–93.| The use of surrounding farmland by western grey kangaroos living in a remnant of wandoo woodland and their impact on crop production.Crossref | GoogleScholarGoogle Scholar |
Blair, G. (1997). Matching pastures to the Australian environment. In ‘Pasture Production and Management’. (Eds J. V. Lovett and J. M. Scott.) pp. 88–109. (Inkata Press: Melbourne.)
Caughley, G. (1987). Ecological relationships. In ‘Kangaroos: Their Ecology and Management in the Sheep Rangelands of Australia’. (Eds G. C. Aughley, N. Shepherd and J. Short.) pp. 159–187. (Cambridge University Press: Melbourne.)
Coleman, J. D., Montague, T. L., Eason, C. T., and Statham, H. L. (1997). The management of problem browsing and grazing mammals in Tasmania. Landcare Research Contract Report LC9596/106. Browsing Animal Research Council, Hobart.
Coleman, J. D., Pech, R. P., Warburton, B., and Forsyth, D. M. (2006). Review of research into alternatives to the use of 1080 for management of browsing damage by mammals in Tasmania. No. LC0506/144. Landcare Research New Zealand for the Department of Primary Industries and Water Tasmania, Hobart.
Cullen, B. R., Eckard, R. J., Callow, M. N., Johnson, I. R., Chapman, D. F., Rawnsley, R. P., Garcia, S. C., White, T., and Snow, V. O. (2008). Simulating pasture growth rates in Australian and New Zealand grazing systems. Australian Journal of Agricultural Research 59, 761–768.
| Simulating pasture growth rates in Australian and New Zealand grazing systems.Crossref | GoogleScholarGoogle Scholar |
Donaghy, D. J., and Tegg, R. (2001) Report of effects of wildlife on pasture growth at Elliot Research & Demonstration Station. Tasmanian Institute of Agricultural Research, University of Tasmania, North West Centre, Burnie.
Edwards, G. P., Croft, D. B., and Dawson, T. J. (1996). Competition between red kangaroos (Macropus rufus) and sheep (Ovis aries) in the arid rangelands of Australia. Australian Journal of Ecology 21, 165–172.
| Competition between red kangaroos (Macropus rufus) and sheep (Ovis aries) in the arid rangelands of Australia.Crossref | GoogleScholarGoogle Scholar |
Hendricks, H. H., Bond, W. J., Midgely, J. J., and Novellie, P. A. (2005). Plant species richness and composition a long livestock grazing intensity gradients in a Namaqualand (South Africa) protected area. Plant Ecology 176, 19–33.
| Plant species richness and composition a long livestock grazing intensity gradients in a Namaqualand (South Africa) protected area.Crossref | GoogleScholarGoogle Scholar |
Hill, G. J. E., Barnes, A., and Wilson, G. R. (1988). The use of wheat crops by grey kangaroos, Macropus giganteus in southern Queensland. Australian Wildlife Research 15, 111–117.
| The use of wheat crops by grey kangaroos, Macropus giganteus in southern Queensland.Crossref | GoogleScholarGoogle Scholar |
Hill, J. O., Simpson, R. J., Moore, A. D., Graham, P., and Chapman, D. F. (2004). Impact of phosphorus application and sheep grazing on the botanical composition of sown pasture and naturalised, native grass pasture. Australian Journal of Agricultural Research 55, 1213–1225.
| Impact of phosphorus application and sheep grazing on the botanical composition of sown pasture and naturalised, native grass pasture.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXhtFWqsLjP&md5=77febadb51ea490c2b72941e009cddb9CAS |
Hutchinson, K. J., King, K. L., and Wilkinson, D. R. (1995). Effects of rainfall, moisture stress, and stocking rate on the persistence of white clover over 30 years. Australian Journal of Experimental Agriculture 35, 1039–1047.
| Effects of rainfall, moisture stress, and stocking rate on the persistence of white clover over 30 years.Crossref | GoogleScholarGoogle Scholar |
Isbell, R. F. (2002). ‘The Australian Soil Classification.’ (CSIRO Publishing: Melbourne.)
Jeffery, S. J., Carter, J. O., Moodie, K. M., and Beswick, A. R. (2001). Using spatial interpolation to construct a comprehensive archive of Australian climate data. Environmental modelling and Software 16, 309–330.
Johnson, C. N., Jarman, P. J., and Southwell, C. J. (1987). Macropod studies at Wallaby Creek. 5. Patterns of defecation by eastern gray kangaroos and red-necked wallabies. Wildlife Research 14, 133–138.
| Macropod studies at Wallaby Creek. 5. Patterns of defecation by eastern gray kangaroos and red-necked wallabies.Crossref | GoogleScholarGoogle Scholar |
Johnson, I. R., Lodge, G. M., and White, R. E. (2003). The sustainable Grazing Systems Pasture Model: description, philosophy and application to the SGS National Experiment. Australian Journal of Experimental Agriculture 43, 711–728.
| The sustainable Grazing Systems Pasture Model: description, philosophy and application to the SGS National Experiment.Crossref | GoogleScholarGoogle Scholar |
Jones, R. M. (1992). Resting from grazing to reverse changes in sown pasture composition: application of the ‘state-and-transition’ model. Tropical Grasslands 26, 97–99.
Jones, R. M., Jones, R. J., and McDonald, C. K. (1995). Some advantages of long-term grazing trials, with particular reference to changes in botanical composition. Australian Journal of Experimental Agriculture 35, 1029–1038.
| Some advantages of long-term grazing trials, with particular reference to changes in botanical composition.Crossref | GoogleScholarGoogle Scholar |
Kemp, D. R. (1999). Managing grassland composition with grazing. In ‘Proceedings from the Bushcare Grassy Landscapes Conference’. (Eds T. Barlow and R. Thorburn.) pp. 145–152. (Environment Australia: Clare, SA.)
Krzic, M., Newman, R. F., Trethewey, C., Bulmer, C. E., and Chapman, B. K. (2006). Cattle grazing effects on plant species composition and soil compaction on rehabilitated forest landings in central interior British Columbia. Journal of Soil and Water Conservation 61, 137–144.
Landsberg, J., James, C. D., Morton, S. R., Müller, W. J., and Stol, J. (2003). Abundance and composition of plant species along grazing gradients in Australian rangelands. Journal of Applied Ecology 40, 1008–1024.
| Abundance and composition of plant species along grazing gradients in Australian rangelands.Crossref | GoogleScholarGoogle Scholar |
Lodge, G. M. (1997). Phalaris. In ‘Technical Bulletin 47 – Grazing Management of Temperate Pastures: Literature Reviews and Grazing Guidelines for Major Species. Vol. Technical Bulletin 47’. (Eds R. D. Fitzgerald and G. M. Lodge.) pp. 8–944. (NSW Agriculture: Orange, NSW.)
McIvor, J. G., and Gardener, C. J. (1995). Pasture management in the semi-arid tropical woodlands: effects on herbage yields and botanical composition. Australian Journal of Experimental Agriculture 35, 705–715.
| Pasture management in the semi-arid tropical woodlands: effects on herbage yields and botanical composition.Crossref | GoogleScholarGoogle Scholar |
McQuillan, P., Ireson, J., Hill, L., and Young, C. (2007) ‘Tasmanian Pasture and Forage Pests: Identification, biology and control.’ (Department of Primary Industries and Water Tasmania: Hobart.)
Pajunen, A., Virtanen, R., and Roininen, H. (2008). The effects of reindeer grazing on the composition and species richness of vegetation in forest-tundra ecotone. Polar Biology 31, 1233–1244.
| The effects of reindeer grazing on the composition and species richness of vegetation in forest-tundra ecotone.Crossref | GoogleScholarGoogle Scholar |
Rawnsley, R. P., Cullen, B. R., Turner, L. R., Donaghy, D. J., Freeman, M., and Christie, K. M. (2009). Potential of deficit irrigation to increase marginal irrigation response of perennial ryegrass (Lolium perenne L.) on Tasmanian dairy farms. Crop and Pasture Science 60, 1156–1164.
| Potential of deficit irrigation to increase marginal irrigation response of perennial ryegrass (Lolium perenne L.) on Tasmanian dairy farms.Crossref | GoogleScholarGoogle Scholar |
Sanford, P., Cullen, B. R., Dowling, P. M., Chapman, D. F., Garden, D. L., Lodge, G. M., Andrew, M. Â. H., Quigley, P. E., Murphy, S. R., King, W. M., Johnston, W. H., and Kemp, D. R. (2003). SGS Pasture Theme: effect of climate, soil factors and management on pasture production and stability across the high rainfall zone of southern Australia. Australian Journal of Experimental Agriculture 43, 945–959.
| SGS Pasture Theme: effect of climate, soil factors and management on pasture production and stability across the high rainfall zone of southern Australia.Crossref | GoogleScholarGoogle Scholar |
SAS Institute Inc (2003). ‘The SAS System for Windows, Version 9.1.’ (SAS: Cary, NC.)
Silsbury, J. H. (1961). A study of dormancy, survival, and other characteristics in Lolium perenne L. at Adelaide, SA. Australian Journal of Agricultural Research 12, 1–9.
| A study of dormancy, survival, and other characteristics in Lolium perenne L. at Adelaide, SA.Crossref | GoogleScholarGoogle Scholar |
Southwell, C. (1989) Techniques for monitoring the abundance of kangaroo and wallaby populations. In ‘Kangaroos, Wallabies and Rat-kangaroos. Vol. 2’. (Eds G. C. Grigg, P. Jarman and I. D. Hume.) pp. 659–693. (Surrey Beatty: Sydney.)
Statham, M. (2000). Demonstration of the economic benefits to grazing from effective wallaby control. A report to the National Feral Animal Control Program, Bureau of Rural Sciences. Tasmanian Institute of Agricultural Research, Launceston.
Statham, M., and Rayner, P. J. (1995). Loss of pasture and crop to native animals in Tasmania In ‘10th Australian Vertebrate Pest Conference’, 1995, Hobart. (Ed. M. Statham.) pp. 171–176.
Statham, M., and Statham, H. L. (2010). ‘Wallaby Proof Fencing: A Planning Guide for Tasmanian Primary Producers.’ Revised edn. (Tasmanian Institute of Agricultural Research: Hobart.)
‘t Mannetje, L. (1978). Measuring quantity of grassland vegetation. In ‘Measurement of Grassland Vegetation and Animal Production’. (Ed. L. ‘t Mannetje.) pp. 63–90. (Commonwealth Agricultural Bureaux, England: Farnham Royal, Buckinghamshire, UK.)
‘t Mannetje, L. (2000). Measuring biomass of grassland vegetation. In ‘Field and Laboratory Methods of Grassland and Animal Production Research’. (Eds L. ‘t Mannetje and R. M. Jones.) pp. 151–177. (CABI Publishing: Wallingford, UK.)
Wardlaw, T., and Burton, D. (2008). ‘Targeted Culling of Browser Species that most Threaten Eucalypt Plantations.’ (Forestry Tasmania: Hobart.)
Yates, C. J., Norton, D. A., and Hobbs, R. J. (2000). Grazing effects on plant cover, soil and microclimate in fragmented woodlands in south-western Australia: implications for restoration. Austral Ecology 25, 36–47.
| Grazing effects on plant cover, soil and microclimate in fragmented woodlands in south-western Australia: implications for restoration.Crossref | GoogleScholarGoogle Scholar |
Zhou, H., Tang, Y., Zhao, X., and Zhou, L. (2006). Long-term grazing alters species composition and biomass of a shrub meadow on the Qinghai–Tibet Plateau. Pakistan Journal of Botany 38, 1055–1069.
