Diversity of ectomycorrhizas in old-growth and mature stands of Douglas-fir (Pseudotsuga menziesii) on southeastern Vancouver Island by Douglas Mark Goodman B.Sc., University of Victoria, 1980 B.Sc., University of Victoria, 1985 M.Sc,, University of Guelph, 1988 A Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY in the Department of Biology We accept this dissertation as conforming to the required standard __________________________________________________ DrOwens, Supervisor (Department of Biology) Dr^~^TÂ^ TrdfymoW^;' Co-Supervisor, Additionaï^Member (Department of feUology) Dr. B.'J. ^awkins. Departmental Member (Department of Biology) Dr7^\lT^ntos, Departmental Member (Department of Biology) ______________________________ Dr.r M>C.K. Edgell, Out^ae Member (Department of Geography) Dr. (S.) Bé-^li, -Additional Member (Research Branch, British Columbia Ministry of Forests) _ ___ Dry R.M. Danielson, External Examiner (Department of Biological Sciences, University of Calgary) © Douglas Mark Gooctoan, 1995 University of Victoria All rights reserved. This dissertation may not be reproduced in whole or in part, by photocopying or other means, without the permission of the author. 11 Supervisor: Dr. John N. Owens ABSTRACT Concern about potential losses of biological diversity and productivity following clear-cut logging of old-growth forests in British Columbia led me to compare ectomycorrhizas in old-growth and mature stands of Douglas- fir . Two sites were selected, each with an old-growth (288-, 441-yr-old) and a mature stand (87-, 89-yr-old) well-matched in tree species, soil and topography. A total of 120 soil cores SI5 cm deep by 5 cm diameter were taken at random from four 60 m square plots (one per stand). Samples were taken in spring and fall at each site. All morphological types of ectomycorrhizas in one half of each core were counted and characterized in detail. Ectomycorrhizal abundance and frequency was compared in logs, stumps, the forest floor over bedrock or gravel, the forest floor near the base of trees, the forest floor elsewhere, and mineral soil. Old-growth and mature stands were very similar in richness, diversity and types of ectomycorrhizas. Sixty- nine types of ectomycorrhizas were described. Nineteen types each accounted for more than one percent of the 17,500 ectomycorrhizal root tips examined, and eighteen types were found in five or more of the 120 soil cores. Extrapolation indicates a total richness of roughly 100 types in the four plots. Co-dominant fungi were Cenococcum geophilvia Fr. (24% of all ectomycorrhizal root tips), a Rhizopogon Fr. of the section villosuli (10%), Hysterangium Vitt. (9%), Lactarius Ill deliciosus (Fr.) S.F.G. (6%), and Piloderma fallax (Libert) Stalpers (4%). Cenococcum geophilum, Rhizopogon Fr, and L. deliciosus were abundant in both mineral soil and organic substrates, Piloderma fallax was associated with decayed wood, and Hysterangium and type 27 were in organic substrates only. A bright greenish-yellow felty type was found in 5 cores in mineral soil only. The similarity of the ectomycorrhizal communities of old- growth and mature stands was probably due to their proximity (< 200 m apart) and the similarity of their vegetation and soil. Differences may occur at some sites if ectomycorrhizal succession has been delayed or redirected as a result of frequent or severe disturbance, lack of old- growth legacies (logs and stumps), or lack of old-growth stands from which fungi can disperse. IV EXAMINERS D r . J .Ne 'Owens/ Supervisor■ (Department(D e of Biology) Dr. ^rPC. Trofymow, Cd-Supervisor, Additional Member (Department of Biology) Dr . b 73\Hdwkins, Departmental Member(Department of Biology) Drt J. Antos, Departmental Member (Department of Biology) Member (Department of Geography) hr. AddictioiiS.l Member (Research Branch, British C o l n m b ^ t-Ministry of Forests) Dr/JR.M. elson, External Examiner (Department of Biological Sciences, University of Calgary) V Table of contents ABSTRACT ........................................... ii Table of contents..................................... v List of tables .................................vii List of figures.................................... ix Acknowledgements ................................... xi General introduction ................................. 1 1. Biological diversity in forest soils ............ 1 2. Practical importance of understanding the ecology of ectomycorrhizas ............................. 1 Chapter One — Diversity of ectomycorrhizal ti"pes . 3 Introduction ......................................... 3 Literature review -- Characterization and identification of ectomycorrhizas ................ 5 1. Introduction ............................... 5 2. Taxonomic diversity of ectomycorrhizal fungi . 5 3. Characterization of ectomycorrhizas .......... 6 4. Identification of ectomycorrhizas ............ 10 5. Descriptions of ectomycorrhizas .............. 14 6. Conclusions............................. 16 Methods and materials ............................. 17 1. Sampling and storage of s o i l ........... 17 2. Extraction of ectomycorrhizas from soil .... 17 3. Separation of types within a soil sample . 18 4. Description of types of ectomycorrhizas .... 18 5. Estimating richness of types ............... 19 Results ........................................... 21 1. Diversity of morphological types of ectomycorrhizas ........................... 21 2. Identity of the ectomycorrhizas......... 22 VI 3. Diversity of characters used to distinguish ectomycorrhizas ............................. 24 Discussio n......................................... 28 Tables’ and f i g u r e s ................................. 35 Chapter Two -- Diversity of ectomycorrhizas in ol growth and mature stands ................................. 65 Introduction ....................................... 65 Literature Review -- Succession of ectomycorrhizas as forests age *•*••••«•••«••**■•* 6 7 1. Methods of studying ectomycorrhizal succession 67 2. Persistence of ectomycorrhizas on nursery seedlings after outplanting................. 68 3. Establishment of ectomycorrhizas on seedlings following clearcutting or f i r e ............ 69 4. Succession of ectomycorrhizas as forests age . 71 5. Differences between early-stage and late-stage f u n g i ..................................... 72 6. Possible explanations of ectomycorrhizal s u c c e s s i o n ............................... 74 Methods and materials ........................... 78 1. Selection of study s i t e s ................... 78 2. Description of sites studied.. ............... 78 3. Sampling design ............................. 80 4. Statistical analysis ....................... 82 Results ............................... 83 D i s c u s s i o n ....................................... 85 Tables and figures ............................... 89 Chapter Three -- Distribution of ectomycorrhizas related to the soil environment ............................ 103 Introduction ...................................... 103 Literature review — Ectomycorrhizas and the cycling of nitrogen in temperate coniferous forests . 105 1. Introduction ..................................105 vil — 2. Nitrogen cycling ........................... 106 3. The role of ectomycorrhizas................ 108 Methods and materials ........................... Ill 1. Nutrient analysis ........................... Ill 2. Data analysis..................................Ill Results ........................................... 113 1. Description of soil habi t a t s .................. 113 2. Abundance and frequency of ectomycorrhizal types in soil-habi.tats............................ 114 3. Relationship of ectomycorrhizal types and soil nutrients................................. 116 4. Correlation and co-occurrence of types .... 117 Dis cus s i o n ....................................... 118 T a b l e s ........................................... 124 General discussion ................................. 134 Literature Cited ................................... 137 Appendix lA. Ectomycorrhizal types -- cent' its of electronic database of characters for 69 types of ectomycorrhizas....................... 154 1. Explanation of fields ....................... 154 2. Contents of database .......................... 164 Appendix IB. Key to ectomycorrhizas ........... 210 Appendix 1C. Descriptions of ectomycorrhizas that are either distinctive, or are common with consistent features...................................... 219 Appendix 2A. Description of sites ............... 227 Tables and figures ............................. 23 0 Appendix 3A. Comparisons of mean nutrient concentrations and other parameters of several soil h a bi t a t s ....................................... 248 T a b l e s ......................................... 249 Vlll List of tables Table 1.1. Ectomycorrhizal taxa ................ 37 Table 1.2. Characters recorded for ectomycorrhizal types (adapted from Agerer 1993 and Ingleby et al. 1990) . 38 Table 2.1. Some cases of ectomycorrhizal succession . 90 Table 2.2. Successional position of some ectomycorrhizal fungi ........................................... 93 Table 2.3. Amount of soil sampled and abundance of ectomycorrhizal root tips and types in the four study plots ........................................... 94 Table 2.4. Analysis of variance of number of root tips at the Koksilah site colonized by the nine most frequent morphological types of ectomycorrhizas.. ..........