MARINE BIRD ASSEMBLAGES IN RELATION TO ARMORED AND UNARMORED SITES IN ...

107 Pages·2016·4.88 MB·English

MARINE BIRD ASSEMBLAGES
IN RELATION TO ARMORED AND UNARMORED SITES
IN CENTRAL PUGET SOUND
*
~~
by
Laura Milleville
~
A Thesis
Submitted in partial fulfillment
of the requirements for the degree
Master of Environmental Studies
The Evergreen State College
June 2015

This Thesis for the Master of Environmental Studies Degree
by
Laura Milleville
has been approved for
The Evergreen State College
by
l
~~£~
Dina Roberts, Ph. D.
Member of the Faculty
r,
June.. ~{)/~
Date
ABSTRACT
Marine Bird Assemblages
in Relation to Armored and Unarmored Sites
in Central Puget Sound
Laura Milleville
The Puget Sound nearshore provides critical habitat to overwintering migratory and
resident marine birds. Long-term monitoring has shown that populations of many marine
bird species are experiencing declines. There has been limited research regarding the
factors driving these trends, and more information is needed if adequate management and
conservation measures are to be implemented. Coastal population growth in the region
has led to extensive use of shoreline armoring to protect development, which has
impacted the nearshore environment. Some prey species, including forage fish, are
deleteriously affected by shoreline armoring. The impacts of armoring on upper trophic
level predators, such as marine birds, are largely unknown. This study examined marine
bird assemblages and behavior at paired armored and unarmored sites in central Puget
Sound. Surveys of marine birds in the nearshore were conducted from January through
March 2015. Findings demonstrated that average abundance and species richness was
significantly greater at armored survey sites; however, results varied between individual
paired sites. The proportion of marine birds in each foraging guild was dependent on
whether or not a site was armored, with piscivorous species comprising a lower
percentage of birds at armored sites. Confounding natural and artificial factors could be
contributing to these results, emphasizing the difficulty in determining what aspects
contribute to habitat use and foraging behavior of marine birds in the nearshore. Further
research is warranted to explore the response of marine bird abundance and behavior in
response to shoreline modification.
Table of Contents
List of Figures .................................................................................v i
List ofTables ..................................................................................v ii
Acknowledgements ...........................................................................v iii
Chapter 1: Introduction and Literature Review ....................................... 1
Introduction ................................................................................... 1
Literature Review ........................................................................... 4
The Puget Sound Nearshore ........................................................ .4
Coastal landforms and processes ......................................... 6
Ecology oft he nearshore ....................................................7
A History of Armoring .............................................................. 9
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Armoring in Puget Sound ............................................................ 14
Impacts of Armoring ................................................................. 16
Physical impacts and effects on coastal processes ..................... 16
Ecological impacts .......................................................... 19
Policy and regulation oft he nearshore .................................. 22
South Central Puget Sound sub-basin .................................... 26
Climate change and the nearshore ....................................... 27
Marine Bird Population Trends in Puget Sound ................................. 28
Marine birds as indicators ................................................. 34
Conclusion ............................................................................. 35
Chapter 2: Article Manuscript: Marine Bird Assemblages in Relation to
Armored and Unarmored Sites in Central Puget Sound ............................ 37
Abstract ................................................................................ 37
Introduction ........................................................................... 38
Methods ............................................................................... 44
Site descriptions ............................................................. 4 7
Statistical analysis .......................................................... 51
Results ................................................................................. 53
Abundance ................................................................... 57
Species richness ............................................................. 58
Species evenness ............................................................ 59
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Foraging behavior .......................................................... 60
Individual sites ............................................................... 62
Discussion ............................................................................. 64
Importance ofthe nearshore as foraging habitat ...................... 64
Confounding/actors ........................................................ 66
Future considerations ...................................................... 69
Conclusion ............................................................................ 72
Chapter 3: Summary, Restoration, & Policy Recommendations .................. 75
Habitat enhancement and restoration .......................................... 76
Policy ............................................................................... 78
Bibliography .................................................................................. 83
Appendix ....................................................................................... 97
v
List of Figures
Figure 1. Survey sites located in South Central Puget Sound .......................... .46
Figure 2. Species composition by survey site ............................................. 56
Figure 3. Mean avifauna! abundance by survey site ..................................... 57
Figure 4. Mean species richness by survey site .......................................... 58
Figure 5. Mean species evenness by survey site .......................................... 59
Figure 6. Proportion of birds foraging by survey site .................................... 60
Figure 7. Analysis of abundance in each foraging guild (B: benthivores;
H: herbivores; 0: omnivores; P: piscivores) in relation to armored and unarmored
sites and according to distance from shore ................................................ 61
Figure 8. Photos of additional development in the nearshore habitat at, and adjacent to,
three survey sites .............................................................................. 67
Figure 9. Map of survey sites with reported statistics ....................................9 7
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List of Tables
Table 1. Total seabird abundance observed by site in South Central Puget Sound,
Washington, January-March 2015 .......................................................... 54
Table 2. Species table: Number of individuals observed at armored and unarmored
sites ............................................................................................. 55
Table 3. Monte Carlo resampling of average abundance between armored and
unarmored sections at each paired survey site ............................................. 63
Table 4. Monte Carlo resampling of average species richness between armored and
unarmored sections at each paired survey site ............................................. 63
Table 5. Key findings from Chapter 2 ..................................................... 75
Table 6. Data collected and reported by Bower (2009) regarding marine bird
population trends in the Salish Sea ......................................................... 98
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Acknowledgements
Dr. Dina Roberts
Dr. Peter Hodum and Ryan Cruz, University ofPuget Sound
Many thanks to Bethany Alender, Sarah Davis, Sean Greene, Chelsea Waddell, and the
rest of my cohort for help with statistics, ArcGIS, editing, and encouragement.
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Chapter 1: Introduction and Literature Review
INTRODUCTION
Humans have been drawn to coastal areas for thousands of years. They benefit
from the numerous ecosystem goods and services provided by the nearshore, including
flood protection, nutrient cycling, water filtration, and nursery habitat for marine species.
Nearshore ecosystems also provide food, cultural value, and opportunities for recreation.
Globally, the economic value of these ecosystem services is estimated at 12.3 trillion
dollars annually (Hoggart et al., 2015).
While people have long been interested in inhabiting coastal areas, the desire to
live near the ocean has come at a cost. Shifting coastlines, rising sea levels, coastal
storms, and floods can damage and destroy property and infrastructure. For centuries,
people have built coastal infrastructure, such as shoreline armoring, to protect their land
and homes from the encroachment of the ocean (Charlier et al., 2005). While coastal
floods and erosion are natural phenomena, extensive coastal urbanization has resulted in
viewing these occurrences as urgent problems. This has led to increasing use of shoreline
armoring to protect development and human interests (Nicholls et al., 2015). At present,
more than 40% ofthe world's population currently lives within 100 km ofthe coast, and
armoring is used worldwide to protect development in coastal areas (Wilson et al., 20 15).
Human populations and associated development pressures in many coastal areas are
growing, and the use of armoring is expected to increase to shield waterfront properties
from waves, floods, and rising sea levels (Nordstrom, 2014). As with many
anthropogenic alterations of the environment, the construction of these armoring
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