Register      Login
Australian Journal of Botany Australian Journal of Botany Society
Southern hemisphere botanical ecosystems
RESEARCH ARTICLE

Knowledge of the reproductive ecology of the invasive Salix cinerea, in its invaded range, assists in more targeted management strategies

Tara Hopley A B C and Andrew G. Young A
+ Author Affiliations
- Author Affiliations

A CSIRO National Facilities and Collections, GPO Box 1600, Canberra, ACT 2601, Australia.

B Research School of Biology, Australian National University, Canberra, ACT 0200, Australia.

C Corresponding author. Email: tara.hopley@dpaw.wa.gov.au

Australian Journal of Botany 63(6) 477-483 https://doi.org/10.1071/BT15018
Submitted: 21 January 2015  Accepted: 20 May 2015   Published: 30 June 2015

Abstract

Management for invasive species is expensive, costing millions of dollars every year and is sometimes unsuccessful. Current control efforts for the highly invasive willow species, Salix cinerea, are extensive, costly, and not always effective because of rapid post-removal reinfestation. An improved knowledge of the reproductive ecology of this species will help design control strategies that minimise future expansion and make current control efforts more effective. To explicitly examine the reproductive ecology of this species in its invaded range in south-eastern Australia, field observations of population structure and sex ratios, pollination experiments and germination trials were undertaken across the Ovens catchment in Victoria. Pollination-exclusion experiments strongly suggest that Salix cinerea in Australia employs two pollen-dispersal mechanisms, with insects being the dominant vector and wind playing a small but significant role (ambophilous). Seed had high initial germination rates, above 95%, but seed is very short-lived with rapid linear decline in germinability until 8 weeks, after which there was no germination at all. An improved understanding of the limited seed bank of this species and the potential it has for long distance pollination has highlighted that preventing reinfestation after control efforts should be focussed on limiting seed production and dispersal. A greater understanding of a species reproductive ecology, particularly of weed species, in their new environment can assist land managers to more effectively target their efforts for long-term eradication strategies.

Additional keywords: germination, pollination, seed longevity, weed, willow.


References

Alliende M, Harper J (1989) Demographic studies of a dioecious tree. I. Colonization, sex and age structure of a population of Salix cinerea. Journal of Ecology 77, 1029–1047.
Demographic studies of a dioecious tree. I. Colonization, sex and age structure of a population of Salix cinerea.Crossref | GoogleScholarGoogle Scholar |

Baker HG (1974) The evolution of weeds. Annual Review of Ecology and Systematics 5, 1–24.
The evolution of weeds.Crossref | GoogleScholarGoogle Scholar |

Cox PA, Grubb PJ (1991) Abiotic pollination: an evolutionary escape for animal-pollinated angiosperms. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences 333, 217–224.
Abiotic pollination: an evolutionary escape for animal-pollinated angiosperms.Crossref | GoogleScholarGoogle Scholar |

Cremer K (1999) Willow management for Australian rivers. Natural Resource Management 2–22.

Cremer K, Kraayenoord C, Parker N, Streatfield S (1995) Willows spreading by seed-implications for Australian river management. Australian Journal of Soil and Water Conservation 8, 18–27.

Densmore R, Zasada J (1983) Seed dispersal and dormancy patterns in northern willows: ecological and evolutionary significance. Canadian Journal of Botany 61, 3207–3216.
Seed dispersal and dormancy patterns in northern willows: ecological and evolutionary significance.Crossref | GoogleScholarGoogle Scholar |

Friedman J, Barrett SC (2009) Wind of change: new insights on the ecology and evolution of pollination and mating in wind-pollinated plants. Annals of Botany 103, 1515–1527.
Wind of change: new insights on the ecology and evolution of pollination and mating in wind-pollinated plants.Crossref | GoogleScholarGoogle Scholar | 19218583PubMed |

Gage EA, Cooper DJ (2005) Patterns of willow seed dispersal, seed entrapment, and seedling establishment in a heavily browsed montane riparian ecosystem. Canadian Journal of Botany 83, 678–687.
Patterns of willow seed dispersal, seed entrapment, and seedling establishment in a heavily browsed montane riparian ecosystem.Crossref | GoogleScholarGoogle Scholar |

Geber MA, Dawson TE, Delph LF (1999) ‘Gender and sexual dimorphism in flowering plants.’ (Springer-Verlag: Berlin)

Greenwood H, O’Dowd DJ, Lake PS (2004) Willow (Salix x rubens) invasion of the riparian zone in south-eastern Australia: reduced abundance and altered composition of terrestrial arthropods. Diversity & Distributions 10, 485–492.
Willow (Salix x rubens) invasion of the riparian zone in south-eastern Australia: reduced abundance and altered composition of terrestrial arthropods.Crossref | GoogleScholarGoogle Scholar |

Grime JP, Hodgson JG, Hunt R (1988) ‘Comparative plant ecology: a functional approach to common British species.’ (Chapman & Hall: London)

Harper D, Witkowski F, Kemp-Mccarthy D, Crabb J (1997) The distribution and abundance of riparian trees in English lowland floodplains. Global Ecology and Biogeography Letters 6, 297–306.
The distribution and abundance of riparian trees in English lowland floodplains.Crossref | GoogleScholarGoogle Scholar |

Hierro JL, Maron JL, Callaway RM (2005) A biogeographical approach to plant invasions: the importance of studying exotics in their introduced and native range. Journal of Ecology 93, 5–15.
A biogeographical approach to plant invasions: the importance of studying exotics in their introduced and native range.Crossref | GoogleScholarGoogle Scholar |

Ingamells P (2008) Weedscene report calls for urgent funding to weed out National Parks threats. Newsletter of the Weed Society of Victoria Inc 19, 1–12.

Junttila O (1976) Seed germination and viability in five Salix species. Astarte: Journal of Arctic Biology 9, 19–24.

Karrenberg S, Suter M (2003) Phenotypic trade-offs in the sexual reproduction of Salicaceae from flood plains. American Journal of Botany 90, 749–754.
Phenotypic trade-offs in the sexual reproduction of Salicaceae from flood plains.Crossref | GoogleScholarGoogle Scholar | 21659171PubMed |

Ladson A, Gerrish G, Carr G, Thexton E (1997) ‘Willows along Victorian waterways: towards a willow management strategy’. (Department of Natural Resources and Environment: Victoria.)

Maroder HL (2000) Storage Behaviour of Salix alba and Salix matsudana Seeds. Annals of Botany 86, 1017–1021.
Storage Behaviour of Salix alba and Salix matsudana Seeds.Crossref | GoogleScholarGoogle Scholar |

Mason CF, Macdonald SM (1990) The riparian woody plant community of regulated rivers in eastern England. Regulated Rivers: Research and Management 5, 159–166.
The riparian woody plant community of regulated rivers in eastern England.Crossref | GoogleScholarGoogle Scholar |

Peeters L, Totland Ø (1999) Wind to insect pollination ratios and floral traits in five alpine Salix species. Canadian Journal of Botany 77, 556–563.
Wind to insect pollination ratios and floral traits in five alpine Salix species.Crossref | GoogleScholarGoogle Scholar |

Read MG, Barmuta LA (1999) Comparisons of benthic communities adjacent to riparian native eucalypt and introduced willow vegetation. Freshwater Biology 42, 359–374.
Comparisons of benthic communities adjacent to riparian native eucalypt and introduced willow vegetation.Crossref | GoogleScholarGoogle Scholar |

Sacchi C, Price P (1988) Pollination of the arroyo willow, Salix lasiolepis: role of insects and wind. American Journal of Botany 75, 1387–1393.
Pollination of the arroyo willow, Salix lasiolepis: role of insects and wind.Crossref | GoogleScholarGoogle Scholar |

Sacchi CF, Price PW (1992) The relative roles of abiotic and biotic factors in seedling demography of Arroyo willow (Salix lasiolepis: Salicaceae). American Journal of Botany 79, 395–405.
The relative roles of abiotic and biotic factors in seedling demography of Arroyo willow (Salix lasiolepis: Salicaceae).Crossref | GoogleScholarGoogle Scholar |

Salick J, Pfeffer E (1999) The interplay of hybridization and clonal reproduction in the evolution of willows: experiments with hybrids of S. eriocephala & S. exigua & S. eriocephala & S.petiolaris. Plant Ecology 141, 163–178.
The interplay of hybridization and clonal reproduction in the evolution of willows: experiments with hybrids of S. eriocephala & S. exigua & S. eriocephala & S.petiolaris.Crossref | GoogleScholarGoogle Scholar |

Sinden J, Jones R, Hester S, Odom D, Kalisch C, James R, Cacho O (2004) ‘The economic impact of weeds in Australia.’ CRC for Australian Weed Management Technical Series no8. (CRC for Australian Weed Management: Glen Osmond, SA)

Snell K (2009) Review of progress towards the National willows strategic plan 2008–2009. Unpublished report. (Victorian Department of Primary Industries: Geelong, Victoria)

Stella JC, Battles JJ, Orr BK, McBride JR (2006) Synchrony of seed dispersal, hydrology and local climate in a semi-arid river reach in California. Ecosystems 9, 1200–1214.
Synchrony of seed dispersal, hydrology and local climate in a semi-arid river reach in California.Crossref | GoogleScholarGoogle Scholar |

Sutherland S (2004) What makes a weed a weed: life history traits of native and exotic plants in the USA. Oecologia 141, 24–39.
What makes a weed a weed: life history traits of native and exotic plants in the USA.Crossref | GoogleScholarGoogle Scholar | 15300483PubMed |

Tamura S, Kudo G (2000) Wind pollination and insect pollination of two temperate willow species, Salix miyabeana and Salix sachalinensis. Plant Ecology 147, 185–192.
Wind pollination and insect pollination of two temperate willow species, Salix miyabeana and Salix sachalinensis.Crossref | GoogleScholarGoogle Scholar |

Thorp JR, Lynch R (2000) ‘The determination of weeds of national significance.’ (National Weeds Strategy Executive Committee: Launceston, Tas.)

Tollsten L, Knudsen JT (1992) Floral scent in dioecious Salix (Salicaceae): a cue determining the pollination system? Plant Systematics and Evolution 182, 229–237.
Floral scent in dioecious Salix (Salicaceae): a cue determining the pollination system?Crossref | GoogleScholarGoogle Scholar |

Ueno N, Suyama Y, Seiwa K (2007) What makes the sex ratio female-biased in the dioecious tree Salix sachalinensis? Journal of Ecology 95, 951–959.
What makes the sex ratio female-biased in the dioecious tree Salix sachalinensis?Crossref | GoogleScholarGoogle Scholar |

Vilà M, Espinar JL, Hejda M, Hulme PE, Jarošík V, Maron JL, Pergl J, Schaffner U, Sun Y, Pyšek P (2011) Ecological impacts of invasive alien plants: a meta-analysis of their effects on species, communities and ecosystems. Ecology Letters 14, 702–708.
Ecological impacts of invasive alien plants: a meta-analysis of their effects on species, communities and ecosystems.Crossref | GoogleScholarGoogle Scholar | 21592274PubMed |

Vranjic JA, Groves RH, Willis AJ (2000) Environmental weed management systems. In ‘Australian weed management systems’. (Ed. BM Sinden) pp. 329–354. (R. G. and F. J. Richardson: Meredith: Vic.)

VSN International (2009) ‘Genstat for Windows. Introduction.’ 12th edn. (VSN International: Hemel Hempstead, UK)