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Physiological ecology of a tropical dragon, Lophognathus temporalis

Christian, Keith A., Bedford, Gavin S., Green, Brian, Griffiths, Anthony D., Newgrain, K. and Schultz, Timothy J. (1999). Physiological ecology of a tropical dragon, Lophognathus temporalis. Australian Journal of Ecology,24(2):171-181.

Document type: Journal Article
Citation counts: Scopus Citation Count Cited 21 times in Scopus Article | Citations

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Title Physiological ecology of a tropical dragon, Lophognathus temporalis
Author Christian, Keith A.
Bedford, Gavin S.
Green, Brian
Griffiths, Anthony D.
Newgrain, K.
Schultz, Timothy J.
Journal Name Australian Journal of Ecology
Publication Date 1999
Volume Number 24
Issue Number 2
ISSN 0307 692X   (check CDU catalogue open catalogue search in new window)
Scopus ID 2-s2.0-18044376646
Start Page 171
End Page 181
Total Pages 11
Place of Publication Carlton Southm, Victoria, Australia
Publisher Blackwell Publishing
HERDC Category C1 - Journal Article (DEST)
Abstract Lophognathus temporalis is an arboreal lizard from the wet–dry tropics of Australia. During the wet season the field metabolic rate (FMR) of the lizards was 209 kJ kg-1 d-1, but during the dry season FMR was only 62 kJ kg-1 d-1. Similarly, water flux decreased from 73.6 mL kg-1 d-1 in the wet season to 18.5 mL kg-1 d-1 in the dry season. Body temperatures (Tb) were significantly lower in the dry season, and operative temperatures, calculated by incorporating microclimatic data with characteristics of the lizards, indicated that the seasonal shift was due to changes in thermoregulatory behaviour rather than limitations of the thermal environment. By combining field measurements of Tb and FMR with laboratory measurements of standard metabolic rate over a range of Tb, we were able to subdivide the FMR into its components and to determine which factors contributed to the seasonal reduction in energy expenditure. During the dry season, lizards used 147 kJ kg-1 d-1 less energy than during the wet season, and 24% of this decrease was estimated to be due to the passive effects of lower nighttime Tb, 14% was due to the active selection of lower daytime Tb, 27% was due to the physiological shift to lower standard metabolic rates, and 35% was due to reduced activity in the dry season. Although the population size remained relatively constant (107 lizards ha-1 during the wet season and 125 lizards ha-1 during the dry season), the population structure changed, reflecting the seasonal patterns of recruitment and mortality. The number of lizards active at any one time was much lower in the dry season, reflecting the lower levels of activity in this season. The energy expenditure of the population of L. temporalis was 612 kJ ha-1 d-1 during the wet season and 113 kJ ha-1 d-1 during the dry season.
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Additional Notes Current title (from 1999) Austral Ecology: a journal of ecology in the Southern Hemisphere (ISSN: 1442-9985)
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