Road Impacts on Abundance, Call Traits, and Body Size of Rainforest Frogs in Northeast Australia

Frogs are potentially sensitive indicators of road impacts, with studies indicating particular susceptibility to road mortality. Calling, i.e., breeding, behavior could also be affected by traffic noise. The authors investigated effects on frog abundance and calling behavior where a busy highway crosses rainforest stream breeding habitat in northeast Australia. Frog abundance was repeatedly surveyed along five stream transects during a summer breeding season. Abundance of two species, Litoria rheocola and Austrochaperina pluvialis, increased significantly with perpendicular distance from the road along two transects. No trends in abundance were detected for A. pluvialis on two other transects where it was common, or for Litoria serrata on one transect where abundance was sufficient for analysis. Both species with lowered abundance near the road, L. rheocola and A. pluvialis, are rare in road kill statistics along this highway, suggesting road mortality is not the cause of reduced frog abundance near the road. The authors postulate that lowered abundance may reflect traffic noise effects. They analyzed calls of the International Union for Conservation of Nature endangered species L. rheocola along the one stream transect on which it was common. They found significant trends in two call traits over a very fine scale: both call rate and dominant frequency were significantly higher closer to the road. Furthermore, males were significantly smaller closer to the road. These call and body size trends most likely reflect road impacts, but resolving these is complicated by correlations between traits. Potential mechanisms, effects on fitness, and management recommendations to mitigate the impacts of roads on frogs are outlined.


  • English

Media Info

  • Media Type: Digital/other
  • Features: Appendices; Figures; Maps; References; Tables;
  • Pagination: pp 1-16
  • Serial:

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Filing Info

  • Accession Number: 01496504
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Oct 25 2013 10:05AM