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RESEARCH ARTICLE
Contents Vol 55(3)

Population-size effects on seeds and seedlings from fragmented eucalypt populations: implications for seed sourcing for ecological restoration

Siegfried L. Krauss A B F , Luise Hermanutz C , Stephen D. Hopper B D and David J. Coates E
+ Author Affiliations
- Author Affiliations

A Science Directorate, Botanic Garden and Parks Authority, Kings Park and Botanic Garden, Fraser Avenue, West Perth, WA 6005, Australia.

B School of Plant Biology, University of Western Australia, Crawley, WA 6005, Australia.

C Department of Biology, Memorial University, St John’s, NL, A1B 3X9, Canada.

D Present address: Royal Botanic Gardens Kew, Richmond, Surrey, TW9, 3AB, UK.

E Science Division, Department of Environment and Conservation, Locked Bag 104, Bentley Delivery Centre, WA 6983, Australia.

F Corresponding author. Email: skrauss@bgpa.wa.gov.au

Australian Journal of Botany 55(3) 390-399 https://doi.org/10.1071/BT06141
Submitted: 9 July 2006  Accepted: 20 November 2006   Published: 18 May 2007

Abstract

Ecological restoration of degraded habitats is a major conservation activity requiring the collection of large amounts of native seed. Seed production and the genetic quality of seed may be influenced by properties of the source population, such as population size and fragmentation, potentially having an impact on restoration goals. We assessed the population-size effects on seed production and seedling performance in two Western Australian wheatbelt eucalypts, Eucalyptus salmonophloia F.Muell. and E. salubris F.Muell. Both species were historically widespread and dominant, but, as a consequence of land-clearing for agriculture, now exist as small, highly fragmented populations throughout the western half of their range. Given their former importance in the landscape, these species will be critical in ecological restoration of the region. We assessed small (n = 6–12) and large (n > 200) remnant populations in a highly fragmented landscape and compared these to large unfragmented populations. Seed number per capsule was dependent on population size and fragmentation for E. salubris, but not for E. salmonophloia. Large, unfragmented populations of E. salubris produced more than twice the number of seeds per capsule (mean = 2.95) than small and/or fragmented populations. However, seed germination, seed weight, seedling survival and seedling vigour to 1 year were independent of population size or fragmentation in both species. Our results suggest that reduced population size and increased fragmentation can negatively affect pollen quantity and/or quality, thereby limiting seed production, although no fitness effects were observed post-seed maturation. We suggest that the relative absence of post-seed maturation fitness effects in these small fragmented populations are a consequence of (1) wide outcrossing resulting from long-distance dispersal of pollen by highly mobile birds among fragmented populations and/or (2) efficient pre- or post-zygotic selection against more homozygous zygotes within fruits so that only relatively outbred seeds mature. The consequences on seed collection for ecological restoration of reduced population size and increased fragmentation for these eucalypts may be fewer seeds for the same collecting effort, but no apparent fitness effects of mature seeds. However, caution should be exercised when harvesting seed from these smaller populations, as over-harvesting may have an impact on recruitment and hence long-term persistence.


Acknowledgements

We thank Robyn Taylor, Rob Holland, Nicholas Alleonard, Lynne Davies, David Wurm, Frank Panette, Julianne McKay, Ratna Sulastin, Robyn Benken, Kaye Crawford and Caroline Blumer for invaluable assistance with field work, seed counts, establishing and monitoring growth experiments and/or data management. We also thank three reviewers for helpful comments on the manuscript. LH thanks Kings Park and Botanic Garden for hosting her while on sabbatical.


References


Agren J (1996) Population size, pollinator limitation, and seed set in the self-incompatible herb Lythrum salicaria. Ecology 77, 1779–1790.
| Crossref | GoogleScholarGoogle Scholar | open url image1

Allee WC (1951) ‘The social life of animals.’ (Beacon: Boston, MA)

Beard JS , Sprenger BS (1984) Geographical data from the vegetation survey of Western Australia. Vegetation Survey of Western Australia Occasional Paper, No. 2. (Vegmap Publications: Perth)

Brown EM , Burbidge AH , Dell AH , Edinger D , Hopper SD , Wills RT (1997) ‘Pollination in Western Australia: a database of animals visiting flowers.’ Handbook No. 15. (WA Naturalists’ Club: Perth)

Burgess VJ, Kelly D, Robertson AW, Ladley JJ (2006) Positive effects of forest edges on plant reproduction: literature review and a case study of bee visitation to flowers of Peraxilla tetrapetala (Loranthaceae). New Zealand Journal of Ecology 30, 179–190. open url image1

Bussell JD, Hood P, Alacs EA, Dixon KW, Hobbs R, Krauss SL (2006) Rapid genetic delineation of local provenance seed collection zones for effective rehabilitation of an urban bushland remnant. Austral Ecology 31, 164–175.
| Crossref | GoogleScholarGoogle Scholar | open url image1

Cane JH (2001) Habitat fragmentation and native bees: a premature verdict? Conservation Ecology 5, 3. open url image1

Carr D (2005) Summary of the Greening Australia seed provenance workshop, Brisbane, Queensland (20 June 2004). In ‘Proceedings of the fifth Australian workshop on native seed biology’. (Eds SW Adkins, PJ Ainsley, SM Bellairs, DJ Coates and LC Bell) pp. 55–68. (Australian Centre for Minerals Extension and Research: Brisbane)

Coates DJ , Byrne M , Elliot C , Sampson J , Yates C (2005) Gene flow and outcrossing in a fragmented landscape: implications for seed sourcing from small remnants. In ‘Proceedings of the fifth Australian workshop on native seed biology’. (Eds SW Adkins, PJ Ainsley, SM Bellairs, DJ Coates, LC Bell) pp. 37–44. (Australian Centre for Minerals Extension and Research: Brisbane)

CoHort Software (2006) Costat. www.cohort.com

Cunningham SA (2000) Depressed pollination in habitat fragments causes low fruit set. Proceedings of the Royal Society of London. Series B. Biological Sciences 267, 1149–1152.
| Crossref | GoogleScholarGoogle Scholar | open url image1

DeMauro MM (1993) Relationship of breeding system to rarity in the lakeside daisy (Hymenoxys acaulis var. glabra). Conservation Biology 7, 542–550.
| Crossref | GoogleScholarGoogle Scholar | open url image1

Dudash MR (1990) Relative fitness of selfed and outcross progeny in a self compatible, protandrous species, Sabatia angularis L. (Gentianaceae): a comparison in three environments. Evolution 44, 1129–1139.
| Crossref | GoogleScholarGoogle Scholar | open url image1

Ellstrand NC, Elam DR (1993) Population genetic consequences of small population size: implications for plant conservation. Annual Review of Ecology and Systematics 24, 217–242.
| Crossref | GoogleScholarGoogle Scholar | open url image1

Ford HA, Paton DC, Forde N (1979) Birds as pollinators of Australian plants. New Zealand Journal of Botany 17, 509–519. open url image1

Frankham R, Ralls K (1998) Conservation biology: inbreeding leads to extinction. Nature 392, 441–442.
| Crossref | GoogleScholarGoogle Scholar | open url image1

Griffin AR, Moran GF, Fripp YJ (1987) Preferential outcrossing in Eucalyptus regnans F.Muell. Australian Journal of Botany 35, 465–475.
| Crossref | GoogleScholarGoogle Scholar | open url image1

Groom MJ (1998) Allee effects limit population viability of an annual plant. American Naturalist 151, 487–496.
| Crossref | GoogleScholarGoogle Scholar | open url image1

Hardner CM, Potts BM (1995) Inbreeding depression and changes in variation after selfing in Eucalyptus globulus subsp. globulus. Silvae Genetica 44, 46–54. open url image1

Higgins PJ , Peter JM , Steele WK (Eds) (2001) ‘Handbook of Australian, New Zealand and Antarctic birds (HANZAB) Vol. 5. Tyrant-Flycatchers to Chats.’ (Oxford University Press: Melbourne)

Hobbs RJ, Yates CJ (2003) Turner Review No. 7. Impacts of ecosystem fragmentation on plant populations: generalising the idiosyncratic. Australian Journal of Botany 51, 471–488.
| Crossref | GoogleScholarGoogle Scholar | open url image1

Holl KD, Crone EE, Schultz CB (2003) Landscape restoration: moving from generalities to methodologies. Bioscience 53, 491–502.
| Crossref | GoogleScholarGoogle Scholar | open url image1

Hopper SD (1981) Honeyeaters and their winter food plants on granite rocks in the central wheatbelt of Western Australia. Australian Wildlife Research 8, 187–197.
| Crossref | GoogleScholarGoogle Scholar | open url image1

Hopper SD, Gioia P (2004) The southwest Australian floristic region: evolution and conservation of global hotspot of biodiversity. Annual Review of Ecology Evolution and Systematics 35, 623–650.
| Crossref |
open url image1

Hopper SD, Moran GF (1981) Bird pollination and the mating system of Eucalyptus stoatei. Australian Journal of Botany 29, 625–628.
| Crossref | GoogleScholarGoogle Scholar | open url image1

Hufford KM, Mazer SJ (2003) Plant ecotypes: genetic differentiation in the age of ecological restoration. Trends in Ecology & Evolution 18, 147–155.
| Crossref | GoogleScholarGoogle Scholar | open url image1

James SH, Kennington WJ (1993) Selection against homozygotes and resource allocation in the mating system of Eucalyptus camaldulensis Denh. Australian Journal of Botany 41, 381–391.
| Crossref | GoogleScholarGoogle Scholar | open url image1

Kelly D , Ladley JJ , Robertson AW , Norton DA (2000) Limited forest fragmentation improves reproduction in the declining New Zealand mistletoe Peraxilla tetrapetala (Loranthaceae). In ‘Genetics, demography and viability of fragmented populations’. (Eds AG Young, GM Clarke) pp. 241–252. (Cambridge University Press: Cambridge, UK)

Kennington WJ, James SH (1997) The effect of small population size on the mating system of a rare clonal mallee, Eucalyptus argutifolia (Myrtaceae). Heredity 78, 252–260.
| Crossref | GoogleScholarGoogle Scholar | open url image1

Krauss SL, Koch JM (2004) Rapid genetic delineation of provenance for plant community restoration. Journal of Applied Ecology 41, 1162–1173.
| Crossref | GoogleScholarGoogle Scholar | open url image1

Krauss SL , Zawko G , Bussell JD , Taylor R , Hood P (2005 a) Towards a genetic provenance atlas for bushland rehabilitation and minesite revegetation in the south-west of Western Australia. In ‘Proceedings of the fifth Australian workshop on native seed biology’. (Eds SW Adkins, PJ Ainsley, SM Bellairs, DJ Coates, LC Bell) pp. 25–36. (Australian Centre for Minerals Extension and Research: Brisbane)

Krauss SL, Koch JM, Vlahos S (2005b) A novel approach for the rapid genetic delineation of provenance for minesite revegetation. Ecological Management & Restoration 6, 153–155.
| Crossref | GoogleScholarGoogle Scholar | open url image1

Lamont BB, Klinkhamer PGL, Witkowski ETF (1993) Population fragmentation may reduce fertility to zero in Banksia goodii—a demonstration of the Allee effect. Oecologia 94, 446–450.
| Crossref | GoogleScholarGoogle Scholar | open url image1

McKay JK, Christian CE, Harrison S, Rice KJ (2005) ‘How local is local?’—A review of practical and conceptual issues in the genetics of restoration. Restoration Ecology 13, 432–440.
| Crossref | GoogleScholarGoogle Scholar | open url image1

Montgomery BR, Kelly D, Robertson AW, Ladley JJ (2003) Pollinator behaviour, not increased resources, boosts seed set on forest edges in a New Zealand Loranthaceous mistletoe. New Zealand Journal of Botany 41, 277–286. open url image1

Potts BM , Wiltshire RJE (1997) Eucalypt genetics and genecology. In ‘Eucalypt ecology. Individuals to ecosystems’. (Eds J Williams, J Woinarski) pp. 56–91. (Cambridge University Press: Cambridge, UK)

Potts BM, Barbour C, Hingston AB, Vaillancourt RE (2003) Turner Review No. 6: Genetic pollution of native eucalypt gene pools—identifying the risks. Australian Journal of Botany 51, 1–25.
| Crossref |
open url image1

Prober SM, Brown AHD (1994) Conservation of the grassy white box woodlands: population genetics and fragmentation of Eucalyptus albens. Conservation Biology 8, 1003–1013.
| Crossref | GoogleScholarGoogle Scholar | open url image1

Sampson JF, Hopper SD, James SH (1989) The mating system and population genetic structure in a bird pollinated mallee, Eucalyptus rhodantha. Heredity 63, 383–393. open url image1

Sampson JF, Hopper SD, James SH (1995) The mating system and genetic diversity of the Australian arid zone mallee, Eucalyptus rameliana. Australian Journal of Botany 43, 461–474.
| Crossref | GoogleScholarGoogle Scholar | open url image1

Sampson JF , Coates DJ , van Leeuwin SJ (1996) Mating system variation in animal-pollinated rare and endangered plant populations in Western Australia. In ‘Gondwanan heritage: past, present and future of the Western Australian biota’. (Eds SD Hopper, JA Chappill, MS Harvey, AS George) pp. 187–195. (Surrey Beatty: Sydney)

Yates CJ, Hobbs RJ (1997) Woodland restoration in the Western Australian wheatbelt: a conceptual framework using a state and transition model. Restoration Ecology 5, 28–35.
| Crossref | GoogleScholarGoogle Scholar | open url image1

Yates CJ, Hobbs RJ, Bell RW (1994) 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 (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, Coates DJ, Elliot C, Byrne M (2006) Composition of the pollinator community, pollination and the mating system for a shrub in fragments of species rich kwongan in south-west Western Australia. Biodiversity and Conservation in press , open url image1

Young A (2005) Non-provenance genetic issues for native seed sourcing. In ‘Proceedings of the fifth Australian workshop on native seed biology’. (Eds SW Adkins, PJ Ainsley, SM Bellairs, DJ Coates, LC Bell) pp. 1–10. (Australian Centre for Minerals Extension and Research: Brisbane)

Young A, Boyle T, Brown T (1996) The population genetic consequences of habitat fragmentation for plants. Trends in Ecology & Evolution 11, 413–418.
| Crossref | GoogleScholarGoogle Scholar | open url image1