Download Editorial Dynamics and processes in the canopy

Austral Ecology (2007) 32, 2–3
10.1111/j.1442-9993.2007.01742.x
Editorial
Dynamics and processes in the canopy of an Australian
tropical rainforest
The forest canopy has been called ‘the last biological
frontier’ and scientific interest in the above-ground
layers of forests is rapidly increasing (Lowman & Nadkarni 1995; Stork et al. 1997; Basset et al. 2003;
Ozanne et al. 2003; Lowman & Rinker 2004). One of
the major stimuli for canopy research has been the
introduction of industrial cranes into forests as a
means of providing safe and easy access to large sections of the canopy. This special edition of Austral
Ecology focuses on ecological research carried out at
the Australian Canopy Crane in the Daintree lowland
rainforests of North-east Queensland. This unusual
research tool was installed in late 1998 and has since
provided long-term access to the forest canopy (Stork
2007). The crane has been used for a wide variety of
research projects including ecology, plant physiology,
micrometeorology and gas exchange. Cranes have
opened up the exploration of the canopy of temperate
and tropical forests in the same way as the submersible
has provided researchers with access to the deep sea.
The Daintree lowlands is home to a highly diverse
and unique flora that reflects its Gondwanian origins
and its refugial nature. In this special issue Laidlaw et al.
(2007) explore the nature of this diversity and how it
has changed over a 5-year period, the first survey being
carried out within a year of a category three cyclone.
Ticehurst et al. (2007) use remote sensing techniques
and conventional aerial photographs to analyse the
patchy nature of the cyclones’ impact. Measuring
canopy biomass is a complex problem and here Liddell
et al. (2007) provide a more accurate assessment than
has previously been made. Elsewhere Boulter et al.
(2006) have examined the phenology of flowering in the
Wet Tropics through examination of herbarium specimens. Here, Inkrot et al. (2007) provide an analysis of a
two year study of the reproductive phenology of one
species of native palm, Normanbya normanybi, the commonest tree species at the crane site. The canopy is a
rich source of epiphytes and in Australasia ‘birds nest
ferns’, Asplenium spp., comprise a large proportion of
the total epiphytic biomass. Freiberg andTurton (2007)
examine how the commonest species, Asplenium nidens,
responds to the lack of rainfall in the dry season and
examine the impacts of prolonged droughts in the
previous 20 years on populations of this species.
The forest canopy has been called ‘the last biotic
frontier’ because of the perceived high biodiversity
there. Elsewhere, Stork and Grimbacher (2006) have
© 2007 Ecological Society of Australia
shown that of the 1473 beetle species collected at the
crane site from 2000 to 2004, approximately a quarter
are canopy specialists, a quarter ground specialists and
the remainder are shared between these two strata.
This dispels the previously untested myth that two
thirds of all insect species are canopy specialists. Here,
Grimbacher and Stork (2007) examine the canopyand ground-associated beetle assemblages at the crane
site and test whether there are trophic guild or body
size patterns that reflect this vertical stratification.
Kitching et al. (2007) examine one of the major components of this biodiversity, the insect visitor assemblage at flowers in the canopy and show that the
visitor profile is plant specific with implications for
pollination. Ants form a large part of the biomass and
diversity of insects in the forest canopy. Many feed on
sugars from extra-floral nectaries and sugars obtained
by tending sap-sucking bugs and their pattern of distribution in the canopy is partly driven by the availability of these food sources. Here, Blüthgen and Stork
(2007) use their examination of the ant community at
the crane site to examine the evidence for the presence
of ‘ant mosaics’ where some species of ants are highly
dominant in complex mature rainforests.The mammal
fauna of the lowland rainforests was thought to be well
known until Rader used the crane to trap in the
canopy. She found that a range of ground-based
species were captured at different heights including the
top layer. One of these was the very rare species, the
prehensile-tailed rat, Pogonomys sp., which appears to
be a canopy specialist. Here, Rader and Krockenberger (2007) look at the impact of rodent consumption and beetle presence on the germination success of
an Australian rainforest seed, Acmena graveolens.
The canopy is the interface between the rainforests
living carbon and biodiversity store and the
atmosphere. In the final paper, Stork et al. (2007)
examine the demand for new research that looks the
impacts of climate change and particularly elevated
CO2 on this ecosystem.
REFERENCES
Basset Y., Novotný V., Miller S. & Kitching R. L., eds. (2003)
Arthropods of Tropical Forests: Spatio-Temporal Dynamics and
Resource Use in the Canopy. Cambridge University Press,
Cambridge.
E D I TO R I A L
Blüthgen N. & Stork N. E. (2007) Ant mosaics in a tropical
rainforest in Australia and elsewhere: a critical review.
Austral Ecol. 32, 93–104.
Boulter S. L., Kitching R. L. & Howlett B. G. (2006) Family,
visitors and the weather – patterns of flowering in tropical
rainforests of northern Australia. J Botany 94, 369–82.
Freiberg M. & Turton S. M. (2007) Importance of drought on
the distribution of the birds nest fern, Asplenium nidus, in the
canopy of a lowland tropical rainforest in north-eastern
Australia. Austral Ecol. 32, 70–6.
Grimbacher P. S. & Stork N. E. (2007) Vertical stratification of
feeding guilds and body size in beetle assemblages from an
Australian tropical rainforest. Austral Ecol. 32, 77–85.
Inkrot D., Sattler D., Geyer C. & Morawetz W. (2007) Flowering
fruiting phenology of Normanbya normanby: (W. Hill) L. H.
Bailey (Arecaceae), a palm endemic to the lowland tropical
rainforest of north-eastern Australia. Austral Ecol. 32, 21–8.
Kitching R. L., Boulter S. L., Howlett B. G. & Goodall K. (2007)
Visitor assemblages at flowers in a tropical rainforest
canopy. Austral Ecol. 32, 29–42.
Laidlaw M., Kitching R. L., Goodall K., Small A. & Stork N. E.
(2007) Temporal and Spatial variation in an Australian
tropical lowland rainforest Plant community. Austral Ecol.
32, 10–20.
Liddell M. J., Nieullet N., Campoe O. C. & Freiberg M. (2007)
Assessing the above-ground biomass of a complex tropical
rainforest using a canopy crane. Austral Ecol. 32, 43–58.
Lowman M. D. & Nadkarni N. M., eds. (1995) Forest Canopies.
Academic Press, London.
Lowman M. D. & Rinker H. B., eds. (2004) Forest Canopies, 2nd
edn. Elsevier Academic Press, San Diego.
© 2007 Ecological Society of Australia
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Ozanne C. M. P., Anhuf D., Boulter S. L. et al. (2003) Biodiversity meets the atmosphere: a global view of forest
canopies. Science 301, 183–6.
Rader R. & Krockenberger A. (2007) The impact of rodent
consumption and beetle presence on the germination
success of an Australian rainforest seed. Austral Ecol. 32,
86–92.
Stork N. E. (2007) The Australian tropical forest canopy crane:
new tools for new frontiers. Austral Ecol. 32, 4–9.
Stork N. E. & Grimbacher P. S. (2006) Beetles assemblages
from an Australian tropical rainforest show that the canopy
and the ground strata contribute equally to biodiversity.
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Stork N. E., Didham R. K. & Adis J., eds. (1997) Canopy
Arthropods. Chapman & Hall, London. 567 pp.
Stork N. E., Balston J., Farquhar G. D. et al. (2007) Tropical
forest canopies and climate change. Austral Ecol. 32, 105–
111.
Ticehurst C., Phinn S. & Held A. (2007) Using multi-temporal
digital elevation model data for detecting canopy gaps in
tropical forests due to cyclone damage: an initial assessment.
Austral Ecol. 32, 59–69.
Nigel E. Stork
Guest Editor
Rainforest CRC at James Cook University
Cairns, Queensland, Australia
Email: [email protected]