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Pollinator rarity as a threat to a plant with a specialized pollination system


Phillips, RD and Peakall, R and Retter, BA and Montgomery, K and Menz, MHM and Davis, BJ and Hayes, C and Brown, GR and Swarts, ND and Dixon, KW, Pollinator rarity as a threat to a plant with a specialized pollination system, Botanical Journal of the Linnean Society, 179, (3) pp. 511-525. ISSN 0024-4074 (2015) [Refereed Article]

Copyright Statement

Copyright 2015 The Linnean Society of London

DOI: doi:10.1111/boj.12336


An increasing diversity of highly specialized pollination systems are being discovered, many of which are likely to be vulnerable to anthropogenic landscape modification. Here, we investigate if a specialized pollination system limits the persistence of Caladenia huegelii (Orchidaceae), an endangered species pollinated by sexual deception of thynnine wasps. Once locally common in part of its geographical range, C. huegelii is now largely restricted to small habitat remnants in urban areas. Pollinator surveys coupled with DNA barcoding detected a single pollinator taxon, a small form of Macrothynnus insignis. Phylogenetic analysis revealed that small M. insignis from within the range of C. huegelii are strongly divergent from other wasp populations, suggesting that some reproductive isolation may exist. Although common in intact landscapes outside the range of C. huegelli, small M. insignis individuals were recorded at only 4% of sites in suitable C. huegelii habitat. Accordingly, reproductive success in C. huegelii was low compared with related Caladenia spp., with 3360% of populations failing to set fruit in any given year. As such, populations are likely to now persist primarily through individual plant longevity rather than reproduction. Due to the low reproductive success of C. huegelii, ongoing human intervention will almost certainly be needed to sustain the species. Future research will need to focus on optimizing hand pollination to maintain reproduction and high seed fitness.

Item Details

Item Type:Refereed Article
Keywords:habitat fragmentation, orchid, sexual deception
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Terrestrial ecology
Objective Division:Environmental Management
Objective Group:Terrestrial systems and management
Objective Field:Terrestrial biodiversity
UTAS Author:Swarts, ND (Dr Nigel Swarts)
ID Code:103212
Year Published:2015
Web of Science® Times Cited:25
Deposited By:Tasmanian Institute of Agriculture
Deposited On:2015-09-28
Last Modified:2017-11-03

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