The occurrence and likely origins of two species of mistletoe at Herdsman Lake, Western Australia

2010·2.5 MB·English

by  R Powell

THE OCCURRENCE AND LIKELY ORIGINS OF TWO
SPECIES OF MISTLETOE AT HERDSMAN LAKE,
WESTERN AUSTRALIA
By R. POWELL
Wembley Downs, W.A.
Email: [email protected]
BACKGROUND the bushlands that remain,
mistletoes have been eliminated
At Herdsman Lake, Perth,
or reduced in occurrence by
Western Australia, there are two
frequent fires. The occurrence of
species of mistletoe (Loran-
mistletoes at a lake on the SCP,
thaceae), Slender-leaved Mistletoe
such as Herdsman Lake, is there¬
(Amyema linophylla) and Stalked
fore significant.
Mistletoe (Amyema miquelii). This
paper describes their occurrences Herdsman Lake is located in the
and discusses their likely origins. City of Stirling, about 5 km from
the ocean and about the same
Mistletoes are ecologically
distance north-west of the Perth
important (e.g. Watson 2001).
G.P.O. The lake, comprising areas
They support various insects, in¬
of open water and beds of the
cluding two butterfly species in
bullrush Typha orientalis
the Perth area whose larvae feed
(Typhaceae), occupies an area of
on their foliage, the Spotted
about 300 ha. This and about 100
Jezebel (Delias aganippe) and the
ha of adjoining land are now set
Satin Azure (Ogyris amaryllis)
aside as Herdsman Lake Regional
(Braby 2000). They are favoured
Park (Department of Conserv¬
nesting-sites for many bird
ation and Land Management
species (Cooney et al. 2006;
2004). The surrounding land is
Watson 2001, 2002). Their
mostly residential, apart from
flowers provide nectar for some
Osborne Park Industrial Area,
birds, such as honeyeaters, and
which extends to the north-east.
their fruits provide food for
others, particularly the Mistletoe- The Park is situated within the
bird (Dicaeum hirundinaceum), sandy, aeolian soils that occupy
which is a mistletoe-specialist roughly the western two thirds of
(Watson 2001, 2002). the SCP, which, at this latitude,
On the Swan Coastal Plain (SCP), extend about 12 km inland from
much of the original vegetation, the coast (Department of Con¬
including mistletoes, has been servation and Environment 1980).
lost through clearing. In many of Some of its trees and shrubs are
168
natural to the site (local species); Soil Association near the eastern
the rest are introduced from other side of the SCP, 27 km or more
parts of Australia or beyond (non¬ from Herdsman Lake (Depart¬
local species). ment of Conservation and
Environment 1980). It does not,
The chief local species, in
however, occur naturally at
decreasing order of abundance,
Herdsman Lake. In a major
are Flooded Gum (Eucalyptus rudis,
bushland study it is not listed for
Myrtaceae), Freshwater Paperbark
any sites on aeolian soils within
(Melaleuca rhaphiophylla, Myrtaceae),
the Region (Government of
Coojong (Acacia saligna, Fabaceae:
Western Australia 2000), and it is
Mimosoideae), Swishbush
not part of the flora of the
(Viminaria juncea, Fabaceae:
Region’s aeolian soils (Bronwen
Faboideae) and Albizia
Keighery, pers. comm.).
(Paraserianthes lophantha, Fabaceae:
Mimosoideae). These species have A concept plan for Herdsman
maintained their presence by Lake was published in 1976
natural reproduction or as a (Metropolitan Region Planning
result of planting. Flooded Gum Authority 1976). I recall that most
and Freshwater Paperbark have of the planting of the non-local
been planted quite extensively, and local trees and shrubs began
particularly along the lake’s about that time. The non-local
northern and north-eastern species have been planted mostly
shores. Coojong, Swishbush and in grassed amenity areas,
Albizia are short-lived. Fresh¬ particularly round the western,
water Paperbark and Flooded northern and eastern sides of the
Gum live much longer, and there lake. Many of the sheoaks were
are specimens of each at among the first species to be
Herdsman Lake that were mature planted.
and well grown in the 1980s.
The non-local species include
OBSERVATIONS
various eucalypts and three
species of sheoak (Casuarinaceae): In March 2008 I observed
River Oak (Casuarina Slender-leaved Mistletoe growing
cunninghamiana), Horsetail (or on a Salt Sheoak at the northern
Coast) Sheoak (C. equisetifolia) and end of the Park, on the western
Salt Sheoak (C. obesa). River Oak side of Popeye Lake (Site 1, Map 1).
and Horsetail Sheoak do not In April 2008 I observed Slender¬
occur naturally in Western leaved Mistletoe growing on Salt
Australia. Salt Sheoak occurs Sheoaks on the eastern side of
widely in Western Australia. Popeye Lake, just north of the
Within the Perth Metropolitan south-west corner of the fence
Region it is found in low-lying that encloses the southern and
alluvial soils on the floodplains of western sides of land held by the
the Swan and Canning rivers, Perth Horse and Pony Club (Site
and in areas of the Beermullah 2, Map 1).
169
Map 1. Occurrences of mistletoe at Herdsman Lake.
About the same time, I found one
specimen of Stalked Mistletoe
growing on an old Flooded Gum
in the east of the Park,
immediately south of the
entrance to the car park off
Herdsman Parade (Site 3, Map 1).
The tree also had what appeared
to be a long-dead mistletoe, as
well as three thickened branch-
ends that were probably
produced by mistletoe haustoria.
The tree is one of a stand of
thirteen, mostly old, Flooded
Gums. No signs of mistletoes were
observed on any of the other
trees. I have not done a systematic
Map 2. Occurrences of Slender-leaved
Mistletoe on the Swan River nearest search of all the Park’s Flooded
to Herdsman Lake. Gums for mistletoe, but on many
170
leisure walks in the Park, often western side of Mill Point, but
incorporating a complete circuit they are still young and, in
of the lake, I have not noticed February 2009, did not host any
any more Stalked Mistletoes. mistletoes. The nearest Salt
Sheoak to Herdsman Lake
In January 2009 I inspected more
supporting mistletoe is at Matilda
thoroughly the Salt Sheoaks near
Bay, Crawley, over two km
Popeye Lake. At Site 1 they
further downstream, immediately
comprised a grove of about 45
south of The University of
trees. Most were of mature size
Western Australia’s Watersports
and probably part of the original
Complex (Site 4, Map 2). In July
plantings, but some smaller ones
2009, it supported one live and
may have been their progeny. All
(what appeared to be) one dead
the mistletoes were growing on
Slender-leaved Mistletoe. This
older trees. I counted a total of 23
spot is about 7.4 km from the
mistletoes, 16 on one host at the
nearest Slender-leaved Mistletoe
eastern end of the group and
at Herdsman Lake. The next-
seven more on other trees. As a
nearest places to Herdsman Lake
result of difficulties in observing
where Slender-leaved Mistletoes
the mistletoes, however, the
grow are near Pelican Point,
number of individual plants may
Crawley (Site 5, Map 2), and the
be considerably more. A
northern end of Coode Street,
Mistletoebird was seen in the
South Perth (Site 6, Map 2), about
most heavily infested sheoak.
8.5 and 9.2 km respectively away
At Site 2, three Salt Sheoaks were
from the Herdsman Lake
spaced 10-20 m apart. There were
mistletoes. A much larger
at least 20 mistletoe plants on the
population of Salt Sheoak is to be
tree nearest the fence corner,
found in Canning River
none on the middle tree and two
Regional Park, about 16 km
on the third one.
south-east of Herdsman Lake, and
No mistletoes were found on any
Slender-leaved Mistletoe is
of the 40 other mature Salt
abundant there.
Sheoaks planted elsewhere at
Herdsman Lake or on any of the It is possible that Slender-leaved
River Oaks or Horsetail Sheoaks Mistletoe may occur on planted
planted round the lake. Salt Sheoaks nearer to Herdsman
Lake; but this host is rarely
The nearest place to Herdsman
planted in Perth’s suburbs except
Lake where Salt Sheoak would
in or near wetlands (pers. obs.
once have occurred naturally is
over many years of noting trees
on the Swan River near The
planted in Perth’s suburbs). In
Narrows, between Melville Water
February 2009 I found no
and Perth Water; but both banks
mistletoes in revegetation plant¬
on this reach were cleared of
ings of Salt Sheoak and two
vegetation long ago. Some Salt
eastern Australian species (River
Sheoaks have been planted just
Oak and Swamp Oak) at Lake
south of The Narrows, on the
171
Monger, 1-2 km south-east of (Eucalyptus gomphocephala). At least
Herdsman Lake. These trees were two of them appear to support
young, the earliest plantings mistletoes. The dominance of
being in 1999 (Ross Bowman, Tuart and the hilly landscape
Town of Cambridge, pers. comm.). suggest that the picture was
Other lakes within 10 km of taken somewhere to the west of
Herdsman Lake are Perry Lakes, the lake, probably in what is now
Lake Claremont, Lake Gwelup, the Perth suburb of Wembley
Lake Karrinyup, Big Carine Downs: the vegetation and
Swamp and Star Swamp. In Feb¬ terrain are similar to those still
ruary and March 2009, I checked present at Hale School.
all except Lake Karrinyup. Salt
Stalked Mistletoe is still very
Sheoaks had been planted in
common on Marri (Corymbia
recent years at some of them but
calophylla) and Wandoo (Eucalyptus
no Slender-leaved Mistletoe was
wandoo) in Perth’s eastern
found. No sheoaks have been
suburbs, and occurs less com¬
planted at Lake Karrinyup (pers.
monly on Flooded Gum and
comm, the groundsman, Lake
Tuart on the SCP (A.N. Start, pers.
Karrinyup Country Club). Two
comm.). Within 10 km of
major bushlands are situated
Herdsman Lake, it persists on
within 10 km of Herdsman Lake,
Marri in Kings Park and near
Kings Park and Bold Park, but
Birdwood Parade, Dalkeith, and
Slender-leaved Mistletoe has not
on Tuart in Bold Park (my
been recorded at either (Bennett
observations and also A.N. Start,
1988, Barratt and Tay 2005).
pers.comm.). The Herdsman Lake
population (albeit now reduced
to one plant) may thus be a
DISCUSSION
remnant of the original
vegetation.
In southwestern Australia,
Stalked Mistletoe grows mainly Salt Sheoak is the only host plant
on eucalypts (Rye 1987). The signs on which Slender-leaved
of former mistletoe haustoria Mistletoe is known to grow in the
observed on the Flooded Gum at Perth Metropolitan Region (Rye
Site 3 indicate that Stalked 1987, A.N. Start pers. comm.). As
Mistletoe has been present in the the host does not occur naturally
area for some time. A photograph at Herdsman Lake or anywhere
published by Powell and else in the belts of aeolian soils
Emberson (1978), entitled Timber: within the Region, Slender¬
Herdsman’s Lake, taken before 1930, leaved Mistletoe probably did not
shows an undulating landscape occur naturally at Herdsman Lake
supporting open woodland of or any lakes near by. It is likely,
eucalypts and banksias. The therefore, that Slender-leaved
eucalypts, at least in the Mistletoe has been transported to
foreground, appear from their Herdsman Lake since 1976 as seed
habit and pale bark to be Tuart from other populations. The
172
nearest of these are on the Swan Slender-leaved Mistletoe they
River, 7.4-9.2 km away. A more support benefits various bird and
probable source may be the insect species. Because Salt
abundant population in Can¬ Sheoak does not occur naturally
ning River Regional Park, at a at Herdsman Lake, however,
distance of at least 16 km. specimens planted, or seedlings
that come up, in the more
The Mistletoebird is known to be
natural parts of the Regional
a common disperser of Australian
Park should be removed.
mistletoes. It has been recorded
from many localities in the Perth
Metropolitan Region (Van Delft
ACKNOWLEDGEMENTS
1997), and was seen near Slender¬
leaved Mistletoes at Herdsman I am grateful to Dr A.N. (Tony)
Lake. It is a relatively fast-flying Start for information provided
bird, capable of speeds of about and suggestions made on this
40 kph. It could easily travel paper, and to Vanda Longman for
between Canning River Regional technical help in preparing the
Park and Herdsman Lake in less maps.
than 30 minutes, which is the
approximate time that a mistletoe
berry takes to pass through the REFERENCES
bird’s digestive tract (John Dell,
BARRETT, R.L. and TAY, E. P.
pers. comm.).
2005. Perth Plants: A Field Guide to
No Slender-leaved Mistletoe was
the Bushland and Coastal Flora of
found on any other species of
Kings Park, Perth, Western Australia.
sheoak growing at Herdsman
Botanic Gardens and Parks
Lake or elsewhere at sites visited
Authority, Perth.
during this study, supporting
BENNETT, E.M. 1988. The Bushland
Rye’s (1987) assertion that Salt
Plants of Kings Park, Western
Sheoak is the only host to
Australia. Kings Park Board, Perth.
Slender-leaved Mistletoe in the
BRABY, M.F. 2000. Butterflies of
Perth Region.
Australia, their Identification, Biology
Since Salt Sheoak does not occur
and Distribution: Volumes 1 & 2.
naturally within the belts of
CSIRO, Collingwood, Victoria.
aeolian soils on the SCP within
Pages 341 700.
the Perth Metropolitan Region, it
COONEY, S.J.N., WATSON, D.M.
should not be included in
and YOUNG, J. 2006. Mistletoe
projects that aim to restore the
Nesting in Australian Birds: A
natural vegetation of any
wetland or dryland sites within Review. Emu, 106:1-12.
that area. At Herdsman Lake it DEPARTMENT OF CON¬
would be desirable to keep the SERVATION AND ENVIRON¬
specimens of Salt Sheoak that MENT. 1980. Atlas of Natural
have been planted in grassed Resources: Darling System: Western
amenity areas, because the Australia. Perth. Map III:
173
Vegetation: Perth and Pinjarra RYE, B.L. 1987. Loranthaceae. Pp.
Sheets. 438-440. In: Marchant, N.G., J.R.
Wheeler, B.L. Rye, E.M. Bennett,
DEPARTMENT OF CON¬
N.S. Lander and T.L. Macfarlane.
SERVATION AND LAND MAN¬
Flora of the Perth Region: Volume 1.
AGEMENT. 2004. Herdsman Lake
Western Australian Herbarium,
Regional Park: Management Plan
Perth.
2004-2013. Conservation Com¬
mission of Western Australia and VAN DELFT, R. 1997. Birding Sites
the City of Stirling, Perth. around Perth. 2nd ed. University
of Western Australia Press,
GOVERNMENT OF WESTERN
Nedlands. 118pp.
AUSTRALIA 2000. Bush Forever
Volume 2. Directory of Bush Forever WATSON, D M. 2001. Mistletoe -
Sites. Department of Environ¬ A Keystone Resource in Forests
mental Protection, Perth. and Woodlands Worldwide.
Annual Review of Ecological Systems
METROPOLITAN REGION
32: 219-249.
PLANNING AUTHORITY. 1976.
Herdsman Lake Concept Plan. Perth. WATSON, D.M. 2002. Effects of
Mistletoe on Diversity: Case-study
POWELL, R., and EMBERSON, J.
from Southern New South Wales.
1978. An Old Look at Trees:
Emu 102: 275-81.
Vegetation of South-Western
Australia in Old Photographs.
Campaign to Save Native Forests,
Perth.
174