Conservation Biology Principles for Forested Landscapes

260 Pages·2014·28.544 MB·English

by  Voller, Joan

Conservation Biology Principles
for Forested Landscapes
This page intentionally left blank
Edited by Joan Voller and Scott Harrison
Conservation Biology Principles
for Forested Landscapes
UBCPress /Vancouver
© B.C. Ministry of Forests 1998
All rights reserved. No part of this publication may be reproduced, stored in a
retrieval system, or transmitted, in any form or by any means, without prior
written permission of the publisher, or, in Canada, in the case of photocopying
or other reprographic copying, a licence from CANCOPY (Canadian Copyright
Licensing Agency), 900 - 6 Adelaide Street East, Toronto, ON M5C 1H6.
Printed in Canada on acid-free paper °°
ISBN 0-7748-0630-3 (hardcover)
ISBN 0-7748-0629-X (paperback)
Canadian Cataloguing in Publication Data
Main entry under title:
Conservation biology principles for forested landscapes
Includes bibliographical references and index.
ISBN 0-7748-0630-3 (bound); ISBN 0-7748-0629-X (pbk.)
1. Forest ecology. 2. Sustainable forestry. I. Voller, Joan, 1960-
II. Harrison, Scott, 1962-
QH541.5.F6C661998 577.3 C97-911075-0
UBC Press gratefully acknowledges the ongoing support to its publishing program
from the Canada Council for the Arts, the British Columbia Arts Council, and the
Department of Canadian Heritage of the Government of Canada.
Set in Stone by Irma Rodriguez
Copy editor: Francis J. Chow
Indexer: Annette Lorek
Printed and bound in Canada by Friesens
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Contents
Preface / ix
Acknowledgements / xi
1 Natural Disturbance Ecology / 3
John Parminter
Definitions / 3
Disturbance Ecology / 3
Landscape Ecology / 5
Background / 6
Science and Research / 6
Forest Resource Management / 8
British Columbia / 8
The Pacific Northwest / 10
Recent Developments / 13
Disturbance Data for British Columbia / 14
Ecological Principles I 17
Natural Disturbance Effects / 17
Small-Scale Disturbances I 17
Large-Scale Disturbances / 20
Biodiversity and Natural Disturbances / 22
The Need for Management that Includes Natural Disturbance
Regimes / 25
Methods for Including Natural Processes in Resource
Management / 27
Scale Issues, Variation, and Predictability / 30
Research Needs / 33
Literature Cited / 35
vi Contents
2 Spatial Patterns in Forested Landscapes:
Implications for Biology and Forestry / 42
Marvin Eng
Definitions / 42
Background / 44
Ecological Principles / 46
Scale and Ecological Hierarchy / 46
Fragmentation / 52
Spatial Patterns in Forested Landscapes / 59
Description of Landscape Patterns / 59
Examples of Forested Landscape Patterns / 62
Creating Landscape Patterns with Forestry / 66
Research Needs / 70
Literature Cited / 72
3 Connectivity / 76
Scott Harrison and Joan Voller
Definitions / 76
Background / 78
Ecological Principles / 84
Maintaining Connectivity / 84
Mechanisms for Maintaining Connectivity / 87
Corridor Location and Design / 89
Corridor Width/91
Summary / 92
Research Needs / 93
Literature Cited / 94
4 Riparian Areas and Wetlands / 98
Joan Voller
Definitions / 98
Background /101
Ecological Principles /105
Riparian Areas, Wetlands, and Fish / 105
Riparian Areas, Wetlands, and Invertebrates /111
Riparian Areas, Wetlands, and Herpetofauna / 113
Riparian Areas, Wetlands, and Birds / 116
Riparian Areas, Wetlands, and Mammals /118
Design and Function of Riparian and Wetland Buffers / 119
Research Needs / 121
Literature Cited / 124
Contents vii
5 Interior Habitat / 130
Angela von Sacken
Definitions / 130
Background / 132
Ecological Principles / 133
Interior Forest Microclimate / 133
Interior Habitat Requirements of Forest Dwellers / 137
Interior Habitat and Herpetofauna / 138
Interior Habitat and Birds / 138
Interior Habitat and Mammals / 140
Reserve (Patch) Design and Interior Forest Habitat / 141
Research Needs /142
Literature Cited / 143
6 Biodiversity and Old-Growth Forests /146
Andy MacKinnon
Definitions / 146
Background / 147
Association and Dependence /148
Ecological Principles / 149
Birds / 150
Species and Abundance /ISO
Cavity-Nesters /151
Other Nesting Birds / 154
Forest Type / 154
Mammals / 155
Insectivores / 155
Rodents / 156
Carnivores / 157
Ungulates / 159
Bats / 159
Reptiles / 160
Amphibians /160
Fish /162
Invertebrates /163
Arthropods / 163
Molluscs /164
Vascular Plants /164
Nonvascular Plants / 167
Fungi / 168
Lichens/170
viii Contents
Research Needs / 172
Literature Cited / 172
7 The Dead Wood Cycle / 185
Eric Lofroth
Definitions / 185
Background / 186
Ecological Principles / 187
Dead Wood Cycling /187
Dynamics of the Dead Wood Cycle / 188
Snags/188
Coarse Woody Debris (CWD) / 189
Large Organic Debris (LOD) /191
The Roles of Dead Wood in the Ecosystem / 192
Ecological Roles of Snags / 192
Ecological Roles of Coarse Woody Debris /199
Ecological Roles of Large Organic Debris / 203
Dead Wood and Ecosystem Processes / 206
Management of the Dead Wood Cycle / 207
Research Needs / 208
Literature Cited / 209
8 Managing for Edge Effects / 215
Joan Voller
Definitions / 215
Background/ 217
Ecological Principles / 218
Edge Effects and Microclimatic and Vegetation Gradients / 218
Edge Effects and Invertebrates / 220
Edge Effects and Herpetofauna / 221
Edge Effects and Birds / 222
Edge Effects and Mammals / 224
Managing for Edge Effects / 226
Stand Level / 226
Landscape Level / 227
Research Needs / 227
Literature Cited / 229
Index / 235
Preface
Among the biotic factors that shape the forested landscape, two organisms
modify the landscape more than any others: bark beetles (Dendroctonus spp.)
and humans. Both can affect large spatial scales of a forested landscape on
very short time scales. Beetles and humans also follow similar phases in
their use of the forest. As they colonize new areas, they use the forest as a
store of provisions for basic survival. Bark beetles use the trees for food and
shelter. Humans use the trees, other plants, and animals provided by the
forest for shelter, fuel, food, and medicine. In both cases, the changes to the
landscape are localized as pockets of trees are killed.
Once they satisfy their primary survival requirements, beetle and human
populations can begin to grow rapidly. Although beetles and humans re-
spond to different cues, the effects on the forest may be similar. For the
beetles, abiotic conditions have important effects on population growth
rates. Late fall frosts and mild winter temperatures can enable explosive
beetle population outbreaks. When these outbreaks occur, the changes to
the forested landscape can be swift and severe. Once humans have attained
their minimal survival requirements, they may view the forest as a source of
commodities rather than provisions. Commodities are traded or sold to raise
the comfort level of daily life. A higher standard of living enables explosive
human population outbreaks. When these outbreaks occur, the changes to
the forested landscape are swift and severe.
The relationship of bark beetles with the forest does not progress beyond
the exploitation phase. For humans, however, the standard of living can
potentially rise to a point where their relationship with the forest enters a
new phase. Basic survival is no longer an issue, and the appetite for ever
more material possessions is sated. In this phase, forested landscapes are
valued as habitat for other organisms, for their aesthetic qualities, and as
places of solace.
This comparison between bark beetles and humans draws attention to a
premise of conservation biology that forms the basis of this book: humans
should interact with the forested landscape in a manner that is ecologically