Aquatic millipedes in Australia: a biological enigma and a conservation saga

4 Pages·1994·0.21 MB·English

by  F. J. Burrows

Aquatic millipedes in Australia:
a biological enigma and a conservation saga
F. J. Burrows1, D. F. Hales' and A. J. Beattie'
'Research Unit for Biodiversity and Bioresources, School of Biological Sciences, Macquarie University, New
South Wales 2109
ABSTRACT
In 1989 a siphonotid millipede was diwvered in moderate numbers under stones submerged in
a creek on the Macquarie University campus in the northern suburbb of Sydney. There were no
previous published reports of aquatic millipedes in Australia. The habitat of the population was sub
sequently threatened by construction of a lake. We describe efforts to protect the millipedes during
construction and suggest improved strategies for conservation of locally threatened invertebrates.
INTRODUCTION breathing cutaneously. There are other
reports of aquatic millipedes from various
Considering the enormous diversity of the
parts of the world, but the phenomenon is
invertebrates, attempts at conservation are
not well enough known to rate a mention in
rare. In Australia and overseas, however, a
general textbooks of invertebrate zoology.
more enlightened attitude is gradually
Even in specialist works on diplopods (Hopkin
developing. It is exemplified by public concern
and Read 1992) their existence is little more
for butterflies and moths, jewel beetles and
than acknowledged. There are no published
dragonflies - perhaps the equivalent of the
reports of aquatic millipedes in Australia: for
more majestic vertebrates. The situation and
example, Williams's authoritative handbook
the problems have been reviewed by New
on freshwater invertebrates (Williams 1980)
(1991, 1993) and the conservation status of
does not mention them.
Australian terrestrial invertebrates has been
extensively summarized by Yen and Butcher
In 1989, while collecting material on campus
(1994). At the research level, the Conservation
for class demonstration, one of us (DH)
Committee of the Australian Entomological
discovered several specimens of a millipede
Society has recently collected data on 146
under stones submerged in Mars Creek, a
projects related to invertebrate conservation
tributary of the Lane Cover River. The
(Hill 1994). In addition, a project funded by
millipedes were observed to occur in quite
the Australian Heritage Commission has
substantial numbers, leading us to wonder
enabled 30 sites of significance in invertebrate
why, after many years of limnological work in
conservation to be nominated for National
the Sydney region, they had not previously
Estate status (Greenslade 1994).
been recorded. Consultation with Australian
In this paper, we describe our experiences arachnologists and overseas millipede
in seeking to protect a population of two taxonomists confirmed that millipedes in
newly-discovered fresh water millipedes fresh water were far from a commonplace
threatened by construction works. Aquatic finding. Dr Rickard R. Hoffman of the
millipedes have been recorded on several Virginia Museum of Natural History placed
occasions, starting from Causard's report the species, on the basis of our brief descriptions
(1903) of polydesmid millipedes under stones and photographs, in the Family Siphonotidae
in French streams. Causard described observa- (Order Polyzoniida), and this was sub-
tions of the millipedes making pumping move- sequently confirmed by Dennis Black (La
ments of the rectal area and concluded that Trobe University). Further enquiries indicated
the rectal wall formed a respiratory surface. that several specimens apparently of the same
The best studied recent case is that of a species siphonotid were present in the Australian
known from the black water swamps of the Museum collection, but these had been
Amazon (Adis 1986; Hopkin and Read 1992). collected in pitfall traps near a creek. Their
This species, Gonographic a& (Pyrgodesmidae) aquatic nature had not been suspected, since
lives submerged as sub-adults for periods of there is no other record of an aquatic
flooding of 5-6 months, feeding on algae and siphonotid from anywhere in the world.
December 1994 Australian Zoologist, Vol. 29(34) 213
It became clear from correspondence that from the Vice-Chancellor (Professor Yerbury)
millipede taxonomy was a job only to be and Deputy Vice-Chancellor (Professor
undertaken by experts, and that the experts Martin), whose backgrounds were much more
were understandably too busy to spend time closely aligned with management than with
on identification or description of our species. biology.
So the matter rested: we continued with teach-
To keep faith with the Executive and to
ing and existing research projects, visiting the
prevent delay to the building programme (the
millipedes occasionally for recreation.
contract had already been signed), speed in
carrying out the search was essential. This
THREAT TO THE MILLIPEDES
was an ideal project for RUBB (Research Unit
In 1991, as part of the second phase of for Biodiversity and Bioresources), a loose
building for the Graduate School of Manage- consortium of members of staff of the School
ment, it was proposed that Mars Creek should of Biological Sciences, with interests in whole
be dammed (above the millipede site) to create organism biology.
a lake. The idea of building a lake to enhance
Within a month, Millisearch 91 had been
the park-like surroundings of the University
devised and implemented, and a report
dated back to its beginnings, but had never
produced. Seventeen sites on 15 creeks in the
been implemented because of lack of funds.
Lane Cover River catchment had been
The Graduate School of Management, how-
investigated and the siphonotid millipede had
ever, was not restricted in this way, and the
been found in nine of them. The smaller milli-
lake was planned to improve the outlook from
pede was also found in some places. The milli-
its new multistar accommodation buildings.
pedes appeared widespread, although a few
Work on the site was to commence within
of the sites were free of any threat from urban
weeks.
and road development. Since neither species
The news of impending construction was seemed limited to the campus area, there was
extremely disturbing. Massive silting of the no compelling argument to delay the building
creek could be expected during excavation; as of the dam. In our report to the administra-
the lake filled, the stream flow would cease tion, we requested that water flow to the creek
completely and the habitat would dry out. We below the dam be maintained and that habitat
knew nothing of the millipedes' requirements disturbance should be kept to a minimum, in
but such disturbance would inevitably be the hope of preserving the local population.
damaging. At the time, no other living We were particularly concerned about siltation
populations were known. and about damage to the clay walls of the
creek, where we suspected that the millipedes
laid their eggs.
ACTION
Our initial action was to revisit the site and
THINGS FALL APART
confirm the presence of the organism. Small
numbers were found, but in the course of the So far all had proceeded smoothly. The
search, something totally unexpected was University Executive were interested and
discovered - a second species of aquatic supportive, and since the millipedes were
millipede! Later it was tentatively identified widespread, building works could proceed
by Drs Black and Hoffman as a pyrgodesmid, without delay. Our recommendations would
somewhat similar in general appearance to ensure that habitat damage was limited and
the Amazonian species. there was a good chance that the millipedes
would survive on campus (they had already
become a local icon, with regular appearances
REACTION
in Posing Show, the student Union magazine,
Driven by concern for the survival of these an account in Arena, the student newspaper,
biologically interesting and potentially rare one in University News, and coverage by
species, we approached the University Sydney newspapers, radio and television).
Executive. Their response was rapid and Members of RUBB returned to the backlog of
positive. If no other populations of the milli- regular business.
pedes were found, the dam would not be con-
structed. We were invited to a institute a search Then we realized that lines of communica-
of other tributaries of the Lane Cover River to tion had broken down. Work commenced and
determine if the species occurred elsewhere proceeded rapidly in late winter and spring of
and were given a small enabling grant of 1991. Almost before the ink had dried on our
$1,000. This was a very gratifying reaction report, a deep silt trap was gouged out of the
214 Australian Z&gist, Vo1.29(3-4) December 1994
creek bed in the midst of the millipede habitat. cracks in the banks. Unlike the French poly-
To make matters worse, the creek upstream desmids, it does not breathe by rectal ventila-
was diverted around the site of the dam wall, tion, but apparently breathes cutaneously.
by cutting a new channel through easily There are no signs of special modifications
erodable clay subsoil. This resulted in a heavy related to aquatic life. Both adult and juvenile
load of silt being carried downstream. Silting forms have been found submerged, and long-
in the trap area was particularly bad. Several term submergence is a normal part of its
millipedes were found (as it happened, under behaviour.
the eyes of Channel 7 cameras) covered in silt
and moribund. Others were dead in deep silt When the Buildings and Grounds engineers
on the rock ledges of the creek. We had little heard of the millipedes' survival, they were a
hope that any members of the original bit inclined to say "I told you so! A lot of fuss
population would survive. Our requests for about nothing!" Nevertheless we consider that
further measures to reduce silting were met the attempt to preserve the local population
sympathetically by the construction company was justified. Survival in the circumstances
(Civil & Civic), whose on-site representatives was more due to good luck than anything else.
were patient and helpful. But the damage had The timing of the construction may have been
already been done. Gradually, all sign of the favourable, coming, as it did, just after the
millipedes disappeared. breeding season. In addition, the weather
remained fine through most of the period,
Why did this happen, in an atmosphere
reducing erosion from the heaps of loose clay
apparently of good will and co-operation? We
resulting from the excavations.
suspect that, by oversight, our recommenda-
tions were not passed on from the Executive to We have continued to collect data on the
the Building and Grounds section responsible biology of the millipedes. Both species are still
for organizing the works. They received only present, but the smaller pyrgodesmid is so
the summary page which reported the finding uncommon (as it has always been) that
of other populations and the green light for nothing is known of its biology. Following
the project to go ahead, and were unaware of initial publicity (Dayton 1991; Hales 1991),
suggestions for minimizing damage. We reports were received of the siphonotid from
expected to be consulted on the recommenda- fresh water and from wet terrestrial environ-
tions of our report, but we were not. Possibly ments in Victoria (see Black, in prep.), so it
too many people and administrative entities seems to be both widespread and secure.
were involved, without clear lines of com- Nonetheless, our investigations gave us cause
munication. Possibly, with assurance that for concern about urban creeks as endangered
other populations existed, it was not con- habitats, which would benefit from active con-
sidered worth the expense of modifying pre- servation efforts.
determined procedures. In any case, it is clear
in hindsight that we should have followed up The siphonotid species is now recognized
our recommendations more actively. as being new, and is being described as part
of a revision of the Australian Siphonotidae
(Black, in prep.). There is no further informa-
RESURRECTION tion on the identity of the pyrgodesmid. Our
biological observations on both species will be
In a somewhat desultory and irregular published elsewhere.
fashion, we continued to visit the site of the
apparently local extinction. In the following
autumn, we again found some specimens of
LESSONS
the siphonotid. With increased expectation of
their survival, we undertook a fortnightly 1. It is possible to get institutional and public
sampling programme, but were disappointed support for projects in invertebrate conser-
when they again disappeared in October. vation, even if the subject organisms are
However, continued regular sampling indicated rather obscure (though at the hands of
that this cyde is characteristic of the biology of the students, they developed a certain
the species. It is present in quite large unexpected charisma).
numbers in and near the water from autumn
to late spring, but is somewhere else during 2. One should assume nothing about the com-
the summer, perhaps burrowed into damp munication of recommendations, and make
soil, or even in the bed of the creek. It leaves sure they appear on the one page summary
the water in large numbers during early of any report. (Busy administrators or
winter to mate and presumably to lay eggs in engineers may only read the summary.)
December 1994 Australian Zoologist, Vol. 29(34) 215
Recommendations must be followed (Zoologisk Museum, Copenhagen) and Dr
through, preferably by a single person Vincent Resh (Univenity of California, Berkeley)
taking responsibility for the project. for their patience in response to many questions
about millipede biology and taxononmy. This
3. The basis of concerns should be explained
is contribution No. 138 from RUBB.
at the outset. In this present case, one of
the main problems was lack of knowledge
REFERENCES
about the biology of the group. Hence we
could not be sure of the likely effect of the Adh, J., 1986. An "aquatic" millipede from central Amazonian
inundation forest. Oecologia 68: 34749.
dam on the population and could not speak
confidently about the conservation status of Causard, M., 1903. Recherches sur la respiration branchiale
chez les myriapodes diplopodes. Bull. rri. Fr Bclg. 37:
the species. The final favourable outcome
461-79, plate XIII.
was not a result of our recommendations.
Dayton, L.. 1991. Tiny millipede stops the bulldozen. New
but occurred unpredictably despite the
Sctmtirl (mppl.), S&r and Education in Aurlrnlia and
habitat destruction. Nm Zeolond 10: 1 (25 May, 1991).
Greenslade, P., 1994. Heritage listing of invertebrate sites in
ACKNOWLEDGEMENTS southeastern Australia. Mem. QId. Mus. 36: 67-76.
Hales, D., 1991. Millhearch: the case of the freshwater
We thank Professor Yerbury and Professor
millipedes. Amt. Ent. Soc. Sci. Canf (abstract).
Martin for their interest in the conservation
Hill, L., 1994. Conservation Committee Report, Australian
of the millipedes, and the members of RUBB
Entomological Society. Mymecia 30: 6. (Cited with
for their enthusiastic participation in the permission of author).
survey. The Buildings and Grounds Office, Hopkin, S. P. and Read. H. J., 1992. The Biolo&v ofMilipedes.
the Graduate School of Management, and Oxford University Press: Oxford and New York.
Civil &Civic all showed considerable forebear- New, T. R., 1991. The "Doctor's Dilemma", or ideals,
ance in the face of unexpected multifooted attitudes and compromise in insect conservation.j . Awt.
interruptions to their construction plans. We Ent. Sac. 30: 97-108.
thank Dr Hoffman, Dr Black, Dr Geoff New, T. R., 1993. Angels on a pin: dimensions of the crisis
in invertebrare conservation. An. Zool. 33: 623-30.
Monteith (Queensland Museum), Dr Mark
Harvey (Museum of Western Australia), Williams, W. D., 1980. Aurhalion FreshwalnLife. Macmillan:
Melbourne.
Dr Michael Gray (Australian Museum),
Dr Bruce Halliday (Australian National Insect Yen. A. L. and Butcher, R. J., 1994. An overriew of the
conservation status of non-marine invertebrates in Aust-
Collection), Dr Peter Johns (University of
ralia. Endangered Spedes Unit, Ausrralian Nature Con-
Canterbury, New Zealand), Dr Henrik Enghoff servation Agency: Canberra.
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