A Comprehensive Study of Orchid Seed Production Relative to Pollination Traits, Plant Density and Climate in an Urban Reserve in Western Australia

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Abstract

The pollination of 20 common terrestrial orchids was studied in a 60-ha urban banksia and eucalypt dominated woodland in Western Australia. Five years of data (24,000 flowers, 6800 plants) measured fruit set relative to floral areas, capsule volumes, climate, phenology, pollination mechanisms, disturbance tolerance and demography. Pollination varied from 0-95% of flowers, floral displays from 90-3300 mm(2) and capsules from 15-1300 mm(3) per spike. Pollination traits strongly influenced outcomes, with self-pollination highest (59-95%), followed by sexually deceptive autumn or winter-flowering (18-39%), visual deception (0-48%) and sexually deceptive spring-flowering (13-16%). Pollination was limited by drought in autumn or spring and cool winter temperatures. Some orchids were resilient to drought and one formed seed after the leaves withered. Plant density had the greatest impact on fruit set for orchids forming large groups, especially for sexually deceptive pollination. Consequently, small group average (SGA) pollination was up to 4x greater than overall averages and peak seed production occurred in the best locations for genetic exchange and dispersal. SGA rates and seedpod volumes were strongly linked to clonality, but not to demographic trends. Resource competition limited flowering at higher plant densities and competition within spikes resulted in smaller, later-forming seedpods. Pollination data from co-occurring common orchids identified five evolutionary trade-offs linked to pollination, provided baseline data for rare species and revealed impacts of changing climate.

Original languageEnglish
Article number123
Number of pages35
JournalDiversity
Volume11
Issue number8
DOIs
Publication statusPublished - Aug 2019

Cite this

@article{13d20b99988d4cbba201fcaedc5126ab,
title = "A Comprehensive Study of Orchid Seed Production Relative to Pollination Traits, Plant Density and Climate in an Urban Reserve in Western Australia",
abstract = "The pollination of 20 common terrestrial orchids was studied in a 60-ha urban banksia and eucalypt dominated woodland in Western Australia. Five years of data (24,000 flowers, 6800 plants) measured fruit set relative to floral areas, capsule volumes, climate, phenology, pollination mechanisms, disturbance tolerance and demography. Pollination varied from 0-95{\%} of flowers, floral displays from 90-3300 mm(2) and capsules from 15-1300 mm(3) per spike. Pollination traits strongly influenced outcomes, with self-pollination highest (59-95{\%}), followed by sexually deceptive autumn or winter-flowering (18-39{\%}), visual deception (0-48{\%}) and sexually deceptive spring-flowering (13-16{\%}). Pollination was limited by drought in autumn or spring and cool winter temperatures. Some orchids were resilient to drought and one formed seed after the leaves withered. Plant density had the greatest impact on fruit set for orchids forming large groups, especially for sexually deceptive pollination. Consequently, small group average (SGA) pollination was up to 4x greater than overall averages and peak seed production occurred in the best locations for genetic exchange and dispersal. SGA rates and seedpod volumes were strongly linked to clonality, but not to demographic trends. Resource competition limited flowering at higher plant densities and competition within spikes resulted in smaller, later-forming seedpods. Pollination data from co-occurring common orchids identified five evolutionary trade-offs linked to pollination, provided baseline data for rare species and revealed impacts of changing climate.",
keywords = "terrestrial orchids, pollination, phenology, climate, density dependence, clonality, disturbance, banksia woodland, urban vegetation, LIPPED SPIDER ORCHID, FRUIT-SET, MYCORRHIZAL FUNGI, SEXUAL DECEPTION, REPRODUCTIVE SUCCESS, NECTAR REWARD, HOT-SPOT, RARITY, CONSERVATION, EVOLUTION",
author = "Brundrett, {Mark C.}",
year = "2019",
month = "8",
doi = "10.3390/d11080123",
language = "English",
volume = "11",
journal = "Diversity",
issn = "1424-2818",
publisher = "MDPI AG",
number = "8",

}

TY - JOUR

T1 - A Comprehensive Study of Orchid Seed Production Relative to Pollination Traits, Plant Density and Climate in an Urban Reserve in Western Australia

AU - Brundrett, Mark C.

PY - 2019/8

Y1 - 2019/8

N2 - The pollination of 20 common terrestrial orchids was studied in a 60-ha urban banksia and eucalypt dominated woodland in Western Australia. Five years of data (24,000 flowers, 6800 plants) measured fruit set relative to floral areas, capsule volumes, climate, phenology, pollination mechanisms, disturbance tolerance and demography. Pollination varied from 0-95% of flowers, floral displays from 90-3300 mm(2) and capsules from 15-1300 mm(3) per spike. Pollination traits strongly influenced outcomes, with self-pollination highest (59-95%), followed by sexually deceptive autumn or winter-flowering (18-39%), visual deception (0-48%) and sexually deceptive spring-flowering (13-16%). Pollination was limited by drought in autumn or spring and cool winter temperatures. Some orchids were resilient to drought and one formed seed after the leaves withered. Plant density had the greatest impact on fruit set for orchids forming large groups, especially for sexually deceptive pollination. Consequently, small group average (SGA) pollination was up to 4x greater than overall averages and peak seed production occurred in the best locations for genetic exchange and dispersal. SGA rates and seedpod volumes were strongly linked to clonality, but not to demographic trends. Resource competition limited flowering at higher plant densities and competition within spikes resulted in smaller, later-forming seedpods. Pollination data from co-occurring common orchids identified five evolutionary trade-offs linked to pollination, provided baseline data for rare species and revealed impacts of changing climate.

AB - The pollination of 20 common terrestrial orchids was studied in a 60-ha urban banksia and eucalypt dominated woodland in Western Australia. Five years of data (24,000 flowers, 6800 plants) measured fruit set relative to floral areas, capsule volumes, climate, phenology, pollination mechanisms, disturbance tolerance and demography. Pollination varied from 0-95% of flowers, floral displays from 90-3300 mm(2) and capsules from 15-1300 mm(3) per spike. Pollination traits strongly influenced outcomes, with self-pollination highest (59-95%), followed by sexually deceptive autumn or winter-flowering (18-39%), visual deception (0-48%) and sexually deceptive spring-flowering (13-16%). Pollination was limited by drought in autumn or spring and cool winter temperatures. Some orchids were resilient to drought and one formed seed after the leaves withered. Plant density had the greatest impact on fruit set for orchids forming large groups, especially for sexually deceptive pollination. Consequently, small group average (SGA) pollination was up to 4x greater than overall averages and peak seed production occurred in the best locations for genetic exchange and dispersal. SGA rates and seedpod volumes were strongly linked to clonality, but not to demographic trends. Resource competition limited flowering at higher plant densities and competition within spikes resulted in smaller, later-forming seedpods. Pollination data from co-occurring common orchids identified five evolutionary trade-offs linked to pollination, provided baseline data for rare species and revealed impacts of changing climate.

KW - terrestrial orchids

KW - pollination

KW - phenology

KW - climate

KW - density dependence

KW - clonality

KW - disturbance

KW - banksia woodland

KW - urban vegetation

KW - LIPPED SPIDER ORCHID

KW - FRUIT-SET

KW - MYCORRHIZAL FUNGI

KW - SEXUAL DECEPTION

KW - REPRODUCTIVE SUCCESS

KW - NECTAR REWARD

KW - HOT-SPOT

KW - RARITY

KW - CONSERVATION

KW - EVOLUTION

U2 - 10.3390/d11080123

DO - 10.3390/d11080123

M3 - Article

VL - 11

JO - Diversity

JF - Diversity

SN - 1424-2818

IS - 8

M1 - 123

ER -