Free Standard AU & NZ Shipping For All Book Orders Over $80!
Register      Login
Australian Journal of Botany Australian Journal of Botany Society
Southern hemisphere botanical ecosystems
RESEARCH ARTICLE

Getting trees on farms the easy way? Lessons from a model of eucalypt regeneration on pastures

Peter A. Vesk A C and Josh W. Dorrough B
+ Author Affiliations
- Author Affiliations

A School of Botany, The University of Melbourne, Parkville, Vic. 3010, Australia.

B Arthur Rylah Institute for Environmental Research, Department of Sustainability and Environment, PO Box 137, Heidelberg, Vic. 3084, Australia.

C Corresponding author. Email: pvesk@unimelb.edu.au

Australian Journal of Botany 54(6) 509-519 https://doi.org/10.1071/BT05188
Submitted: 1 November 2005  Accepted: 2 March 2006   Published: 15 September 2006

Abstract

Substantial revegetation is required across much of Australian agricultural landscapes. Managers need to minimise the risks of failure and costs associated with revegetation. Whereas ‘natural regeneration’ of eucalypts is relatively cheap compared with direct seeding or planting tubes, natural regeneration in grazed lands occurs infrequently and under limited circumstances. Management needs to understand the situations in which natural regeneration is most likely to occur and what actions can improve the chances of regeneration. We used a rule- and stage-based model of eucalypt regeneration focusing on events between seed supply and sapling escape to synthesise current knowledge and learn how to improve the success rate of natural regeneration of eucalypts. The model used deterministic rules but with stochastic rainfall, and fire was applied stochastically as well as deterministically. Results from simulations suggested that low-productivity pastures have greater likelihood of supporting saplings than do high-productivity pastures. Fire and grazing can increase the chances of subsequent germination and early seedling survival, particularly in high-productivity pastures. As a result, management actions, such as fire and strategic grazing, can improve the probability of sapling establishment in a high-productivity pasture; however, frequency and timing of management actions are important. The following three sources of uncertainty appear crucial: first, variability in rainfall; second, uncertainty about rainfall effects on stage transitions; and third, variability in seed supply. These uncertainties can overwhelm improvements to the chances of regeneration owing to management interventions. Because rainfall and seed supply have overwhelming effects on the process of regeneration, they limit the ability of managers to influence the outcomes and this makes investment in natural regeneration inherently risky. Thus, better data are needed on the effect of rainfall on stage transitions and on spatial and temporal variation in seed supply. This would aid managers to estimate the likelihood of success of regeneration, and make decisions about if, when and where to invest in natural regeneration and what actions to implement.


Acknowledgments

Mick McCarthy, Sue McIntyre and Charles Todd are thanked for comments on drafts. J. D. was supported by funding through Land & Water Australia Native Vegetation R&D program and the Land, Water & Wool Native Vegetation and Biodiversity subprogram.


References


Allcock KG, Hik DS (2004) Survival, growth, and escape from herbivory are determined by habitat and herbivore species for three Australian woodland plants. Oecologia 138, 231–241.
Crossref | GoogleScholarGoogle Scholar | PubMed | open url image1

Andersen AN (1989) How important is seed predation to recruitment in stable populations of long-lived perennials. Oecologia 81, 310–315. open url image1

Andersen AN, Ashton DH (1985) Rates of seed removal by ants at heath and woodland sites in southeastern Australia. Australian Journal of Ecology 10, 381–390.
Crossref |
open url image1

Clarke PJ (2002) Experiments on tree and shrub establishment in temperate grassy woodlands: seedling survival. Austral Ecology 27, 606–615.
Crossref | GoogleScholarGoogle Scholar | open url image1

Clarke PJ, Davison EA (2001) Experiments on the mechanism of tree and shrub establishment in temperate grassy woodlands: seedling emergence. Austral Ecology 26, 400–412.
Crossref | GoogleScholarGoogle Scholar | open url image1

Cluff D, Semple WS (1994) Natural regeneration—in ‘Mother Nature’s’ own time. Australian Journal of Soil and Water Conservation 7, 28–33. open url image1

Cremer KW (1977) Distance of seed dispersal in eucalypts estimated from seed weights. Australian Forest Research 7, 225–228. open url image1

Davidson NJ, Reid JB (1989) Response of eucalypt species to drought. Australian Journal of Ecology 14, 139–156.
Crossref |
open url image1

Dorrough J, Moxham C (2005) Eucalypt establishment in agricultural landscapes and implications for landscape-scale restoration. Biological Conservation 123, 55–66.
Crossref | GoogleScholarGoogle Scholar | open url image1

Garden DL, Ellis NJS, Rab MA, Langford CM, Johnston WH, Shields C, Murphy T, Holmberb M (2003) Fertiliser and grazing effects on production and botanical composition of native grasslands in south-east Australia. Australian Journal of Experimental Agriculture 43, 843–859.
Crossref | GoogleScholarGoogle Scholar | open url image1

Gibbons P, Boak M (2002) The value of paddock trees for regional conservation in an agricultural landscape. Ecological Management & Restoration 3, 205–210.
Crossref | GoogleScholarGoogle Scholar | open url image1

House SM (1997) Reproductive biology of eucalypts. In ‘Eucalypt ecology: individuals to ecosystems’. (Eds JE Williams, JCZ Woinarski) pp. 30–55. (Cambridge University Press: New York)

Inouye RS, Huntly NJ, Tilman D, Tester JR, Stillwell M, Zinnel KC (1987) Old-field succession on a Minnesota sand plain. Ecology 68, 12–26.
Crossref | GoogleScholarGoogle Scholar | open url image1

Jansen A, Robertson AI (2001) Relationships between livestock management and the ecological condition of riparian habitats along an Australian floodplain river. Journal of Applied Ecology 38, 63–75.
Crossref | GoogleScholarGoogle Scholar | open url image1

Keatley MR, Fletcher TD, Hudson IL, Ades PK (2002) Phenological studies in Australia: potential application in historical and future climate analysis. International Journal of Climatology 22, 1769–1780.
Crossref | GoogleScholarGoogle Scholar | open url image1

Law B, Mackowski C, Schoer L, Tweedie T (2000) Flowering phenology of myrtaceous trees and their relation to climatic, environmental and disturbance variables in northern New South Wales. Austral Ecology 25, 160–178.
Crossref | GoogleScholarGoogle Scholar | open url image1

Lawrence J, Semple WS, Koen TB (1998) Experimental attempts at encouraging eucalypt regeneration in non-native pastures of northern Victoria and central western NSW. Proceedings of the Linneaen Society of New South Wales 119, 137–154. open url image1

Leigh JH, Holgate MD (1979) The responses of the understorey of forests and woodlands of the Southern Tablelands to grazing and burning. Australian Journal of Ecology 4, 25–45.
Crossref |
open url image1

McCarthy MA, Possingham HP, Gill AM (2001) Using stochastic dynamic programming to determine optimal fire management for Banksia ornata. Journal of Applied Ecology 38, 585–592.
Crossref | GoogleScholarGoogle Scholar | open url image1

Moles AT, Westoby M (2004) What do seedlings die from and what are the implications for evolution of seed size? Oikos 106, 193–199.
Crossref | GoogleScholarGoogle Scholar | open url image1

Noble IR (1984) Mortality of lignotuberous seedlings of Eucalyptus species after an intense fire in montane forest. Australian Journal of Ecology 9, 47–50.
Crossref |
open url image1

Pettit NE, Froend RH (2000) Regeneration of degraded woodland remnants after relief from livestock grazing. Journal of the Royal Society of Western Australia 83, 65–74. open url image1

Pettit NE, Ladd PG, Froend RH (1998) Passive clearing of native vegetation: livestock damage to remnant jarrah (Eucalyptus marginata) woodlands in Western Australia. Journal of the Royal Society of Western Australia 81, 95–106. open url image1

Pook EW, Gill AM, Moore PHR (1997) Long-term variation of litter fall, canopy leaf area and flowering in a Eucalyptus maculata forest on the south coast of New South Wales. Australian Journal of Botany 45, 737–755.
Crossref | GoogleScholarGoogle Scholar | open url image1

Prober SM, Thiele KR, Koen TB (2004) Spring burns control exotic annual grasses in a temperate grassy woodland. Ecological Management & Restoration 5, 131–134. open url image1

Sankaran M, Ratnam J, Hanan NP (2004) Tree-grass coexistence in savannas revisited - insights from an examination of assumptions and mechanisms invoked in existing models. Ecology Letters 7, 480–490.
Crossref | GoogleScholarGoogle Scholar | open url image1

Saunders DA , Hobbs RJ (1995) Habitat reconstruction: the revegetation imperative. In ‘Conserving biodiversity; threats and solutions’. (Eds RA Bradstock, TD Auld, DA Keith, RT Kingsford, D Lunney, DP Sivertsen) pp. 104–112. (Surrey Beatty: Sydney)

Schirmer J , Field J (2000) The cost of revegetation. Final Report to Environment Australia. ANU Forestry & Greening Australia, Canberra.

Semple WS, Koen TB (1997) Effect of seedbed on emergence and establishment from surface sown and direct drilled seed of Eucalyptus spp. and Dodonaea viscosa. The Rangeland Journal 19, 80–94.
Crossref | GoogleScholarGoogle Scholar | open url image1

Semple WS, Koen TB (2001) Growth rate and effect of sheep browsing on young eucalypts in an anthropogenic Themeda grassland. Rangeland Journal 23, 182–193.
Crossref | GoogleScholarGoogle Scholar | open url image1

Semple WS, Koen TB (2003) Effect of pasture type on regeneration of eucalypts in the woodland zone of south-eastern Australia. Cunninghamia 8, 76–84. open url image1

Spooner P, Lunt ID, Robinson W (2002) Is fencing enough? The short-term effects of stock exclusion in remnant grassy woodlands in southern NSW. Ecological Management & Restoration 3, 117–126.
Crossref | GoogleScholarGoogle Scholar | open url image1

Starfield AM , Bleloch AL (1986) ‘Building models for conservation and wildlife management.’ (Macmillan Publishing: New York)

Stoneman GL (1994) Ecology and physiology of establishment of eucalypt seedlings from seed: a review. Australian Forestry 57, 11–30. open url image1

Stoneman GL, Dell B (1994) Emergence of Eucalyptus marginata (jarrah) in Mediterranean-climate forest in response to overstorey, site, seedbed and seed harvesting. Australian Journal of Ecology 19, 96–102.
Crossref |
open url image1

Stoneman GL, Dell B, Turner NC (1994) Mortality of Eucalyptus marginata (jarrah) seedlings in Mediterranean-climate forest in response to overstorey, site, seedbed, fertilizer application and grazing. Australian Journal of Ecology 19, 103–109.
Crossref |
open url image1

Wellington AB, Noble IR (1985a) Post-fire recruitment and mortality in a population of the mallee Eucalyptus incrassata in semi-arid, south-eastern Australia. Journal of Ecology 73, 645–656.
Crossref | GoogleScholarGoogle Scholar | open url image1

Wellington AB, Noble IR (1985b) Seed dynamics and factors limiting recruitment of the mallee Eucalyptus incrassata in semi-arid, south-eastern Australia. Journal of Ecology 73, 657–666.
Crossref | GoogleScholarGoogle Scholar | open url image1

Yates CJ, Hobbs RJ (1997) Temperate eucalypt woodlands - a review of their status, processes threatening their persistence and techniques for restoration. Australian Journal of Botany 45, 949–973.
Crossref | GoogleScholarGoogle Scholar | open url image1

Yates CJ, Hobbs RJ, Bell RW (1994a) Factors limiting the recruitment of Eucalyptus salmonophloia in remnant woodlands. I. Pattern of flowering, seed production and seed fall. Australian Journal of Botany 42, 531–542.
Crossref | GoogleScholarGoogle Scholar | open url image1

Yates CJ, Hobbs RJ, Bell RW (1994b) Landscape-scale disturbances and regeneration in semi-arid woodlands of southwestern Australia. Pacific Conservation Biology 1, 214–221. open url image1

Yates CJ, Taplin R, Hobbs RJ, Bell RW (1995) Factors limiting the recruitment of Eucalyptus salmonophloia in remnant woodlands. II. Post-dispersal seed predation and soil seed reserves. Australian Journal of Botany 43, 145–155.
Crossref | GoogleScholarGoogle Scholar | open url image1

Yates CJ, Hobbs RJ, Bell RW (1996) Factors limiting the recruitment of Eucalyptus salmonophloia in remnant woodlands. III. Conditions necessary for seed germination. Australian Journal of Botany 44, 283–296.
Crossref | GoogleScholarGoogle Scholar | open url image1

Yates CJ, Hobbs RJ, Atkins L (2000) Establishment of perennial shrub and tree species in degraded Eucalyptus salmonophloia (salmon gum) remnant woodlands: effects of restoration treatments. Restoration Ecology 8, 135–143.
Crossref | GoogleScholarGoogle Scholar | open url image1