Challenges and opportunities for aquatic ecosystem management with uncertain global change ...

143 Pages·2017·9.56 MB·English

Challenges and opportunities for aquatic ecosystem management
with uncertain global change

Timothy J Cline

A dissertation

submitted in partial fulfillment of the

requirements for the degree of

Doctor of Philosophy

University of Washington

2017

Reading Committee:

Daniel E. Schindler, Chair

Ray Hilborn

Daniel S. Holland

Program Authorized to Offer Degree:

School of Aquatic and Fishery Sciences
© Copyright 2017

Timothy J Cline
University of Washington

Abstract

Challenges and opportunities for aquatic ecosystem management
with uncertain global change

Timothy J Cline

Chair of the Supervisory Committee:
Professor Daniel E. Schindler
School of Aquatic and Fishery Sciences

Society is faced with the task of effectively managing to enable ecosystem resilience to
anthropogenic stressors and future change. Ecosystems are part of complex social-ecological
systems where humans impact ecosystems and anthropogenic change and natural variability feed
back to impact people. Management of ecosystems also involves balancing different ecosystem
services and values that people place on ecosystems. These complex challenges for the
management of social-ecological systems require interdisciplinary approaches that address these
challenges from multiple scales.
In this dissertation, I examine patterns and processes in ecosystems and social-ecological
systems that may provide opportunities for management to overcome some of the challenges for
the future. In chapter one, I assess how multiple stressors impact the life cycle of a commercially
important fish species and demonstrate that multiple stressors impact important life-history
complexity with implications for population stability. These changes may make populations less
reliable for commercial fisheries. In the second chapter, I evaluate the interaction between two
competing ecosystem services and show that common ecological processes including density-
dependence and population stochasticity reduce the strength of the interaction between them and
render multiple benefits from ecosystems with a relatively simple management strategy. In my
third chapter, I examine how population density and stream habitat characteristics interact to
influence the habitat usage of sockeye salmon on the spawning grounds, which can alter their
ecological benefit to freshwater ecosystems and the effectiveness of habitat restoration. In my
final chapter, I explore how human communities can exploit complexity in the natural
environment to buffer against uncertainty and catastrophic shifts in social-ecological systems.
This work takes an interdisciplinary approach to addressing these challenges for
management. The research spans multiple scales from species to ecosystems and incorporates
humans in complex social-ecological systems. Management of ecosystems is challenging due to
the immense amount of complexity. However, complexity in nature can provide stability and
opportunities for management to take advantage of to improve management outcomes given
uncertain global change.
Table of Contents

Table of Contents…………………………………………………………………………………..i
List of Figures…………………………………………………………………………………….iii
Acknowledgements………………………………………………………………………………..v
General Introduction………………..……………………………………………………………..1
Chapter 1. Effects of global change on the complex life cycle of an exploited species…………..9
1.1 Abstract………………………………………………………………………………..9
1.2 Introduction…………………………………………………………..……………....10
1.3 Results ………………………………………………………………………...……..13
1.4 Discussion……………………………………………………………………..……..18
1.5 Methods…………………………………………………………………………..…..21
1.6 References……………………………………………………………………..……..27
1.7 Figures…………………………………………………………………………....…..30
Chapter 2. Density-dependence and scale mismatch shape ecosystem service tradeoffs………..36
2.1 Abstract…………………………………………………………………………..…..36
2.2 Introduction……………………………………………………………………....…..37
2.3 Methods………………………………………………………………………..……..40
2.4 Results………………………………………………………………………………..48
2.5 Discussion…………………………………………………………………..………..53
2.6 References…………………………………………………………………..………..59
2.7 Figures……………………………………………………………………..………....62
Chapter 3. Watershed geomorphology affects density-dependent habitat selection of spawning
sockeye salmon…………………………………………………………………………..69
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3.1 Abstract……………………………………………………………………..………..69
3.2 Introduction…………………………………………………………………..……....70
3.3 Methods………………………………………………………..……………..……....74
3.4 Results………………………………………………………………………..……....77
3.5 Discussion…………………………………………………..………………..……....79
3.6 References…………………………………………………..…………………..…....86
3.7 Figures………………………………………………………………………..……....88
Chapter 4. Fisheries portfolio diversification and turnover buffer Alaskan fishing communities
from abrupt resource and market changes. ………………………………………………..…….92
4.1 Abstract ……………………………………………………………………...………92
4.2 Introduction…………………..………………………………………………..……..93
4.3 Results…………………..………………………………………………………..…..96
4.4 Discussion…………………..……………………..………………………………..101
4.5 Methods…………………..………………………..………………………………..104
4.6 References…………………………….………………………………………...…..109
4.7 Figures…………………..…………………………………………………………..111
Appendix A. Supplementary Material for Chapter 1 …………………..…………………..…..116
Appendix B. Supplementary Material for Chapter 2…………………..………………...……..122
Appendix C. Supplementary Material for Chapter 4……………………………………….…..126
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List of Figures
Figure 1.1. Long term age composition of sockeye salmon from seven of the major river systems
draining into Bristol Bay, Alaska…………………………………………………..…….30
Figure 1.2. Environmental changes in freshwater and ocean habitats for Bristol Bay sockeye
salmon………………………………………………………………………………..…..31
Figure 1.3. Changes in the duration of freshwater residency of sockeye salmon………..………32
Figure 1.4. Changes in the age at maturation of sockeye salmon………………………..……....34
Figure 2.1. Ecological relationships forming the basis for a tradeoff between commercial salmon
fisheries and trout growth in spawning watersheds………………………………..…….62
Figure 2.2. Important controls on the shape of production possibilities frontiers for tradeoffs
between commercial fishery production and resident fish growth…………..…….…….64
Figure 2.3. Observed spawning densities in streams from the Wood River system across a range
of total escapement to the system…………………………………………....…….…….66
Figure 2.4. Stochastic production possibilities frontier for tradeoffs between commercial salmon
fisheries and resident fish growth…………....……………………………..……………67
Figure 2.5. Stochastic production possibilities frontiers under two scenarios of resident fish
movement………………………………………………………………...………………68
Figure 3.1. Conceptual model for two possible realizations of the IFD, the resulting spatial
distributions, and effects on spatial evenness……………………………………………88
Figure 3.2. Spatial distribution of spawning sockeye salmon under different population sizes in
seven streams spanning a gradient of watershed slopes…………………………………89
Figure 3.3. Evenness in the spatial distribution as a function of population abundance across 18
streams……………………………………………………………………..……………90
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Figure 3.4. Watershed slope controls the influence of density on the distribution of salmon…...91
Figure 4.1. Ocean regime changes and market shifts impact fisheries catch and revenue……..111
Figure 4.2. Variation in diversification of fishing opportunities across Alaskan communities..113
Figure 4.3. Diversification and turnover of fishing opportunities buffer against abrupt
shifts………………………………………………………………………………….....114
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Acknowledgements
The research I present in this dissertation has been influenced by a large number of
colleagues and collaborators, which have greatly improved the rigor of this research and the
overall impact. These collaborations reflect the outstanding research environment present in the
School of Aquatic and Fishery Sciences and the University of Washington. I have many
individuals and funding sources to thank, for without their support this work would not have
been possible.
First, I want to thank my advisor, Daniel Schindler. Daniel has influenced my science and
my career in more ways than I can even express. Two impacts that I value most are a positive
outlook on environmental issues for the future, and conducting question-driven impactful
research. I have spent a lot of time with Daniel in Alaska field camps. I truly appreciate his
mentorship, friendship, and support for my to pursue many different ecological questions.
Dan Holland, Ray Hilborn, and Sergey Rabotyagov were excellent committee members
and all have played valuable roles in improving my research and my approach. Dan Holland
provided me with important economic foundations for my research while recognizing that I am
an ecologist working to make my research relevant to management. Ray and I interacted many
times both in the field camps in Alaska and in Seattle. He has been valuable in challenging me to
think about difficult questions regarding resource management. Ray has shaped and improved
my critical thinking and approach to science. Sergey, my Graduate School Representative, was
very enjoyable in meetings. He was genuinely interested in my research and my development. I
appreciate his input and support. Thank you to Dan, Ray, and Sergey.
I have been fortunate to work with several long-term data sets collected with the help of
many people. Thank you Jackie Carter and many people who have worked with the Alaska
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Salmon Program at the University of Washington. Thank you to Alaska Department of Fish and
Game and Curry Cunningham reconstructions of age and run information for Bristol Bay
sockeye. Thank you to the Commercial Fisheries Entry Commission for keeping incredible
records of fishing activities in Alaska, organizing that data, and making it publically available.
Multiple sources of funding made this research possible. Financial support for my
dissertation was provided by the National Science Foundation through a Graduate Research
Fellowship and from a Coupled Human Natural Systems grant, and the School of Aquatic and
Fisheries Sciences. I also received fellowships support from the School of Aquatic and Fishery
Sciences.
My friends and family have been supportive of this process throughout and have
provided encouragement, patience, and fun times. Most importantly, my wife Kim has been my
biggest ally, dealt with the long hours, struggles with work-life balance, and patience through it
all. Without her support I would not be the scientist I am today. I love you Kim, thank you for all
of your support.
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