How do beetle assemblages respond to cyclonic dist

Authors: Peter S Grimbacher Nigel E Stork

Publish Date: 2009/07/14

Volume: 161, Issue: 3, Pages: 591-599

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Abstract

There are surprisingly few studies documenting effects of tropical cyclones including hurricanes and typhoons on rainforest animals and especially insects considering that many tropical forests are frequently affected by cyclonic disturbance Consequently we sampled a beetle assemblage inhabiting 18 upland rainforest sites in a fragmented landscape in northeastern Queensland Australia using a standardised sampling protocol in 2002 and again 12 months after the passage of Severe Tropical Cyclone Larry March 2006 The spatial configuration of sites allowed us to test if the effects of a cyclone and those from fragmentation interact From all insect samples we extracted 12568 beetles of 382 species from ten families Beetle species composition was significantly different preand postcyclone although the magnitude of faunal change was not large with 205 species representing 96 of all individuals present in both sampling events Sites with the greatest changes to structure had the greatest changes in species composition At the site level increases in woody debris and woodfeeding beetle Scolytinae counts were significantly correlated but changes in the percent of ground vegetation were not mirrored by changes in the abundance of foliagefeeding beetles Chrysomelidae The overall direction of beetle assemblage change was consistent with increasing aridity presumably caused by the loss of canopy cover Sites with the greatest canopy loss had the strongest changes in the proportion of species previously identified in the precyclone study as preferring arid or moist rainforest environments The magnitude of fragmentation effects was virtually unaltered by the passage of Cyclone Larry We postulate that in the shortterm the effects of cyclonic disturbance and forest fragmentation both reduce the extent of moist interior habitatWe thank the Queensland Parks and Wildlife Service and the many landowners Coombers Crawfords Holdens Littles Stockers Pam Taylor and Margit Cianelli for generously providing access to forest fragments Carl Wardhaugh and Marios Aristophanous are thanked for their assistance in the field Specimen preparation was assisted by Earthwatch volunteers Annette Bryan Danielle Lisle Sue Stork Michelle Larkman and Patricia Voigt Comments from John Kanowski greatly improved the manuscript We thank the JCUCSIRO Tropical Landscapes Joint Venture and the Skyrail Rainforest Foundation for financial support

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