Saproxylic insect communities in boreal mixedwoods of northeastern Ontario as a function of variation in woody debris quality and quantity and sampling methods By Robert William James Dennis A thesis submitted in conformity with the requirements for the degree of Master of Science in Forestry Graduate Faculty of Forestry University of Toronto © Copyright by R.W. James Dennis 2009 Saproxylic insect communities in boreal mixedwoods of northeastern Ontario as a function of variation in woody debris quality and quantity and sampling methods. Masters of Science in Forestry. 2009. R.W. James Dennis, Faculty of Forestry, University of Toronto. Abstract Saproxylic insects rely on dead or dying wood at some point in their development and appear to be sensitive to forest management. In 2005 and 2006, I sampled saproxylic insects in mixedwood boreal forests in northeastern Ontario to assess effects of: 1) different logging practices, 2) variations in woody debris (WD) qualities, and 3) different sampling methods. I also compared insect communities between heavily decayed WD and soil. Although I collected data on all arthropod orders, I focused on the families of the Diptera and parasitic Hymenoptera and the morphospecies of the Scelionidae and Diapriidae. These insects showed clear responses to the WD quality treatments, but not to the different logging treatments. A few families were affected by ex situ sampling. I also found that the faunas of soil and WD are rather distinct from each other. This study shows that WD is a source of forest biodiversity. Consequently, sustainable forest management will rely on studies like this to conserve and maintain the biodiversity of Canada's largest group of eco-zones. ii Acknowledgements The initial concept of this thesis relied on the foresight and hard work of my supervisors, Jay Malcolm and Sandy Smith. For this, and for unequivocal encouragement, statistical advice, and support, I owe them a debt of gratitude. For honest and fair criticism, as well as support and advice, I am grateful to my committee members Chris Darling and Peter de Groot. I am thankful for the contagious excitement for parasitoid taxonomy of Lubomír Masner, Matt Yoder and Md. Nurul Islam (who identified all my scelionid morphospecies). I must thank my field and lab assistants Laura Harris, Justin Carroll, Agniezska Sztaba and Adam Kuprevicius, who were indispensable. Thanks are owed to the SFMN/MCM field campers for keeping me sane during field seasons and for collecting much of the WD data. Thanks also to the Ontario Ministry of Natural Resources office staff in Kapuskasing for letting me use their lab and storage buildings, and to the administrative staff at the Faculty of Forestry who were always helpful and courteous. Finally, I am deeply grateful for the support and love of family and friends, and especially my wife, which were integral to seeing this project to its completion. This research was possible through the financial contributions of the Sustainable Forest Management Network and the Faculty of Forestry at the University of Toronto. iii Table of Contents General Introduction .................................................................................................................... 1 Thesis Objectives and Outline .................................................................................................... 4 Chapter 1: Saproxylic insect abundance and diversity as a function of logging history and woody debris species and decay class in boreal mixedwood forests of northeastern Ontario ......................................................... 6 Introduction ................................................................................................................................... 6 Methods .......................................................................................................................................... 9 Study Site .................................................................................................................................... 9 Site Selection ............................................................................................................................ 10 Sampling Design ....................................................................................................................... 11 Insect Sampling and Identification ........................................................................................... 12 Habitat Sampling ...................................................................................................................... 12 Data Analyses ........................................................................................................................... 13 Results .......................................................................................................................................... 14 Habitat Data .............................................................................................................................. 14 Overall Abundances .................................................................................................................. 15 Statistical Analyses ................................................................................................................... 16 Discussion..................................................................................................................................... 18 Chapter 2: Saproxylic insect abundance and diversity as a function of logging history, woody debris species, and woody debris type in the boreal forest of northeastern Ontario .............................................................................. 38 Introduction ................................................................................................................................. 38 Methods ........................................................................................................................................ 40 Results .......................................................................................................................................... 41 Habitat Data .............................................................................................................................. 41 Abundances ............................................................................................................................... 41 Statistical Analyses ................................................................................................................... 42 Discussion..................................................................................................................................... 44 Chapter 3 – Abundances of saproxylic insects in boreal mixedwood forests of northeastern Ontario as a function of sampling method ............................... 61 Introduction ................................................................................................................................. 61 iv Methods ........................................................................................................................................ 63 Insect Sampling ......................................................................................................................... 63 Data Analysis ............................................................................................................................ 64 Results .......................................................................................................................................... 66 Abundance, Richness, and Diversity ........................................................................................ 66 Univariate and Multivariate Analyses ...................................................................................... 69 Discussion..................................................................................................................................... 71 Chapter 4 – A comparison of insect communities between soil and heavily decayed wood in boreal mixedwood forests of northeastern Ontario .............. 98 Introduction ................................................................................................................................. 98 Methods ...................................................................................................................................... 100 Insect Sampling ....................................................................................................................... 100 Data Analyses ......................................................................................................................... 101 Results ........................................................................................................................................ 102 Abundance .............................................................................................................................. 102 Richness and Diversity ........................................................................................................... 103 Univariate and Multivariate Analyses .................................................................................... 104 Discussion................................................................................................................................... 107 General Discussion ...................................................................................................................