GLOBAL PATTERNS OF FRESHWATER FISH COMMUNITIES IN
MEDITERRANNEAN BIOMES
Elif Esther Fehm-Sullivan
B.S., California State University, Sacramento, 2003
THESIS
Submitted in partial satisfaction of
the requirements for the degree of
MASTER OF SCIENE
in
BIOLOGICAL SCIENCES
at
CALIFORNIA STATE UNIVERSITY, SACRAMENTO
FALL
2010
GLOBAL PATTERNS OF FESHWATER FISH COMMUNITIES IN
MEDITERRANNEAN BIOMES
A Thesis
by
Elif Esther Fehm-Sullivan
Approved by:
__________________________________, Committee Chair
Jamie Kneitel, Ph.D.
__________________________________, Second Reader
Brett Holland, Ph.D.
__________________________________, Third Reader
Patrick Foley, Ph.D.
__________________________________
Date
ii
Student: Elif Esther Fehm-Sullivan
I certify that this student has met the requirements for format contained in the University
format manual, and that this thesis is suitable for shelving in the Library and credit is to
be awarded for the thesis.
__________________________, Graduate Coordinator
Susanne Lindgren, Ph.D.
Department of Biological Sciences
iii
___________________
Date
Abstract
of
GLOBAL PATTERNS OF FRESHWATER FISH COMMUNITIES IN MEDITERRANNEAN
BIOMES
by
Elif Esther Fehm-Sullivan
Explaining patterns of species richness is a central theme in community ecology.
Ecologists have focused on local (within a site), regional (among sites in a given region),
or geographical (among regions) explanations of diversity patterns. In the case of
freshwater fish, studies illustrate that biological factors (competition and predation),
along with physical factors (habitat diversity, water chemistry, flow regime, temperature
and channel morphology), interact to influence species richness within and among
communities and that both operate within a range of spatial scales.
This study identified global patterns of species richness and trophic diversity in
twelve Mediterranean biome freshwater fish communities located on six continents.
Differences were found in both species richness and trophic diversity between continental
river basins. This study also examined energetic, ecological, and historical factors that
may explain freshwater fish species richness and trophic diversity among Mediterranean
biome river basins. The energetic factor, average annual discharge, was found to explain
species richness; and that none of the seven factors measured explained trophic diversity.
This result is contrary to studies that have shown net primary productivity as explaining
species richness in global freshwater fish communities. The difference presented in this
iv
study states that all basin studies were in one habitat type, the Mediterranean biome,
whereas other studies examined several varying habitat types. The resulting specific
knowledge can help conserve species richness and manage river basins altered by human
activity.
___________________________, Committee Chair
Jamie Kneitel, Ph.D.
___________________________
Date
v
DEDICATION
In loving memory of Sherwood Anthony Fehm Jr. and Saba Phyllis Fehm-Sullivan.
vi
ACKNOWLEDGMENTS
Completing a Masters is truly a marathon event, and I would not have
been able to complete this journey without the aid and support of countless people
over the past seven and a half years. I would like to express my gratitude to my
supervisor, Dr. Jamie Kneitel, whose expertise, understanding, and patience added
considerably to my graduate experience. I appreciate his vast knowledge and skill
in many areas (e.g., statistical analysis, community ecology, and dry humor), and
his assistance in writing. I also want to thank him for his calm reserve during
times of stress. I would like to thank the other members of my committee, Dr.
Bret Holland, and Dr. Patrick Foley for the assistance they provided at all levels
of my thesis project. Finally, I would like to thank Dr. Susanne Lindgren, the
Graduate Student Advisor, for giving me the opportunity to finish my thesis.
I would like to give my eternal gratitude to my father James E. Sullivan
for the guidance and wisdom that he has given me throughout my life. I have
been able to develop and grow as an individual as a result. He provided me with
moral, emotional, and writing support during this entire process. I doubt I will
ever be able to convey my appreciation fully. I must also acknowledge the quiet,
constant, intense and enduring support of my mother Sadie Çançar Sullivan. A
very special thank you goes to Dr. Barbara Cordonii, who years ago diagnosed
my learning disabilities, and with whose tutelage enabled me to reach this level of
vii
education. Without her motivation and encouragement, I would not have
considered a graduate career.
viii
TABLE OF CONTENTS
Page
Dedication .......................................................................................................................... vi
Acknowledgments............................................................................................................. vii
List of Tables .......................................................................................................................x
List of Figures .................................................................................................................... xi
Introduction ..........................................................................................................................1
Methods................................................................................................................................9
Results ................................................................................................................................11
Discussion ..........................................................................................................................24
Conclusion .........................................................................................................................29
Appendix A. Trophic level richness per drainage basin. ...................................................32
Appendix B. Data sources..................................................................................................33
Appendix C. Species lists and trophic level.......................................................................34
Appendix D. Table of environmental factor values per drainage basin ............................42
Appendix E. Calculation table for NPP .............................................................................43
Literature Cited ..................................................................................................................44
ix
LIST OF TABLES
Page
Table 1. Trophic Level ANOVA ......................................................................................14
Table 2. Species Richness ANOVA .................................................................................16
Table 3. Continental Trophic Richness ANOVA. ............................................................18
Table 4. Multiple Regression on Species Richness and Trophic Diversity. .....................21
x
LIST OF FIGURES
Page
Figure 1. Global map of Mediterranean Biome Locations .................................................8
Figure 2. Trophic Level Histogram. .................................................................................15
Figure 3. Species Richness Histogram..............................................................................17
Figure 4. Continental Trophic Species Richness Histogram. ...........................................19
Figure 5. Continental Community Composition Chart. ....................................................20
Figure 6. Species Richness Regression with the San Joaquin River. ...............................22
Figure 7. Species Richness Regression without the San Joaquin River. ..........................23
xi
1
INTRODUCTION
A central issue in both biogeography and community ecology is to understand the
factors that shape species richness patterns across different spatial scales (Cody and
Mooney, 1978; Griffiths, 2006). Among vertebrates, fish have been one of the most
intensely studied groups for local (within river), regional (among rivers), and
geographical (among regions) community structure. Numerous common patterns in fish
community organization have been identified among distinct river basins at several
different spatial scales. For example, at a local scale, physical factors appear to
determine species richness in variable environments (Capone and Kushlan, 1991). On
larger spatial scales (regional and geographical), physical factors such as area, total
discharge, and primary productivity, along with historical factors such as speciation rates
and dispersal are the major determinant of species richness and regulate the importance
of local-scale factors (Lamoureux et al., 2002).
To better understand freshwater fish communities, ecologists have studied several
aspects of community structure. These include biogeographic histories and their relation
to the distribution of freshwater fishes (Novacek, 1976; Bernatchez and Wilson, 1998;
McDowall, 2002; Landini and Sorbini, 2005; Goren and Ortal, 1998), diversity of
trophic categories (feeding patterns) (Tonn, 1990; Winemiller, 1991; Behrens and
Lafferty, 2007; Daufresne and Boёt, 2007; Erös, 2007; Mittelbach et al., 2007; Lévêque
et al., 2008), and species richness (Hawkins et al., 2003; Oberdorff et al., 1995; Guégan
et al., 1998; Oberdorff et al., 2001; Griffiths, 2006; Reyjol et al., 2007).
2
The inland water fishes of the Mediterranean have been studied since the first
description of Tilapia galieae by Peter Artedi, considered the father of Ichthyology, more
than 200 years ago (Goren and Ortal, 1998). Some biogeographers have recognized the
importance of the isolation of fishes, and distinct drainages in shaping species richness
and diversity. For example, Lyons and Willig (2002) noted that isolation preserved the
products of speciation events which occurred either within single bodies of water, or
when waters became fragmented and rejoined. Each isolated lake or river system tends to
have its own characteristics and a substantial number of endemic species. In some cases,
the present distribution of freshwater fishes has been shaped by millions of years of
change in global water cycles (Lèvêque et al., 2008). Due to these constantly changing
global water cycles (i.e. glaciation, water availability and temperature variation due to
climate change), the nature and dynamics of freshwater systems have evolved
continuously, at various spatial and temporal scales (Lèvêque et al., 2008). Although
clearly there can be important differences among the fish species present in tributaries
within any basin, species are typically more similar in any location within a river basin
than they are among locations in neighboring basins (Griffiths, 2006). These basins and
waterways can provide natural laboratories for the study of community structure and the
processes that influence them. The similarities among some of the fishes in these
historically isolated systems suggest broad-scale parallelism or convergence (Dyer, 2000;
Cussac et al., 2004; Landini and Sorbini, 2005).
Most studies of assemblage organization in stream fish address the effects of
inter-specific interactions and environmental variation on assemblage structure and
3
resource use (Moyle and Light, 1996). Some effort has been devoted to quantifying
large-scale variation and the multi-scale determinants of assemblage patterns and
processes (Bernatchez and Wilson, 1998). As a result, it is uncertain whether
determinants of local structure and function can be extrapolated to explain assemblage
patterns over broad regional scales (Bernatchez and Wilson, 1998). Moreover,
knowledge of the influence of regional constraints and historical processes on species
distribution, abundance, and assemblage composition remain general, although this
knowledge has been considered critical for advancement in stream fish ecology and
conservation (Poff, 1997). Because as a general rule fish only move by swimming, no
other single factor is more important in regional biogeography of freshwater fishes and
drainage basin limits and affinities (Koleff et al., 2003).
Spatial variability in species diversity patterns are primarily explained by three
hypotheses. These include the (1) species-area theory (Preston, 1962), which predicts
that species richness increases as a power function of surface area; (2) species-energy
theory (Wright, 1983), which predicts that species variation is correlated with energy
availability in the system; and (3) historical theory (Whittaker, 1977), which explains
richness gradients, on a global scale, by patterns of recolonization and maturation of
ecosystems after glaciation (Guégan et al., 1998). This study undertakes an exploration
to determine if any of these hypotheses for freshwater vertebrates (fishes) in similar
climates holds true. Much research on the community ecology of temperate freshwater
streams has been conducted in North America, and some researchers have assumed that
the patterns observed in North America should be applicable elsewhere (Reyjol et al.,
4
2007; Rühland et al., 2008). Notably, this assumption has recently been called into
question (Hendry and Stearns, 2004).
In the circum-Mediterranean region, there is a
dearth of information about factors causing the large-scale spatial structuring of fish
assemblages. It is also doubtful whether the frameworks developed for temperate streams
can be directly translated to such semiarid systems (Reyjol et al., 2007).
Mediterranean ecosystems largely occur along the western edges of continents
between the 30° and 40° parallels in both northern and southern hemispheres. The
world’s five Mediterranean-climate ecosystems are limited to: the region bordering the
Mediterranean Sea; central Chile; the Cape region of South Africa; southwestern and
southern Australia; and all of California south to upper Baja California (Illes, 1978;
Moyle, 2002; Morgan, 2003; Figure 1). Moderated by cold ocean currents offshore, the
Mediterranean climate is characterized by mild, rainy winters and warm, dry summers
(Underwood et al., 2009). ). This favorable climate has made the Mediterranean Biome
densely populated by humans (Clavero et al., 2004).
Consequently, these regions suffer from multiple threats, including deforestation
and desertification that result from urbanization, agriculture, recreation and other human
activities. Invasive plants and animals are also drastically altering the ecosystem and its
biodiversity in all of the five Mediterranean regions of the world. As a result, the
Mediterranean biome, occurring on three percent of the earth’s total land area, is one of
the most highly altered and imperiled ecosystems on the planet, with the most disturbed
area of any biome (Underwood et al., 2009). In concert with high biodiversity and
5
endemism, this has resulted in all Mediterranean biome locations considered biodiversity
hotspots (Myers et al., 2000).
Several studies have focused on comparisons of physical characteristics of
species, species richness, and composition of Mediterranean biome communities within
one continental location, or between two different continental locations. These studies
have focused on the status of the high level of species richness and endemism in plant
communities (Mooney and Dunn, 1970; Cody and Mooney, 1978; Arroyo and Cavieres,
1991; Heywood, 1993; Cowling et al., 199; and Underwood et al., 2009). They have also
included avian communities (Kark and Sol, 2005) and freshwater fish communities
(Bernardo et al., 2003; Clavero at al., 2004; Darwall and Smith, 2006; Pascual et al.,
2007). Very few studies have focused on the communities or organisms found within the
Mediterranean biome and compared them across continents. These studies include those
done by Mooney and Dunn (1970) on Mediterranean plant species, which focused on the
physical similarities of plants illustrating instances of convergent evolution due to
similarities in climate, despite separate distinct evolutionary histories. Additionally,
Cody and Mooney (1978) found similar occurrences of convergent evolution due to
similar climates in their review of Mediterranean plant communities, in addition to other
similar studies that focused on bird and lizard communities (Kark and Sol, 2005;
Ioannidis, 2008).
No studies have looked specifically at freshwater fish trophic diversity within a
similar but isolated biome and compared them across continents, including the
Mediterranean biomes. Most fish assemblage comparisons are done across varying
6
latitudinal gradients of differing biotic regions such as Arctic, Nearctic, Tropical, and
Temperate regions (Winemiller, 1991), or are used to identify ichthyological “provinces”
of the world (Lèvêque et al., 2008).
In addition, studies have been done to investigate
the freshwater icthyofauna of several Mediterranean streams (Goren and Ortal, 1999;
Kleynhans, 1999; Dyer, 2000; Kadye and Marshall, 2007). Many of these have been
conducted to establish a baseline of species present after urbanization and/or to monitor
restoration measures (Corbacho and Sanchez, 2001; Bernardo et al., 2003; Clavero et al.,
2004; Clavero et al., 2005; Habit et al., 2006; Magalhães et al., 2007). There are
however, no comparative studies of global freshwater fish community patterns within a
similar biome or latitudinal location. What makes the study of patterns in the
Mediterranean biome so uniquely compelling is its location. Being equidistant to the
Equator, this location minimizes or even eliminates any latitudinal gradient effects on
species richness and trophic diversity (Winemiller, 1991; Mittelbach et al., 2007).
The purpose of this study was to compare freshwater fish community richness and
structure among Mediterranean biomes, which have similar climatic conditions and
minimal latitudinal gradient effects. Differences of community trophic diversity and
species richness were tested between the biome locations, and related to measurable
physical parameters. These parameters were hydrology, geology, ecology, and climate.
The hydrological parameters included total drainage basin area in square kilometers and
mean annual discharge at the river mouth in cubic meters per second. The geological
parameters were total surface area of the continent and area of glaciation. The ecological
7
parameter was net primary productivity. Finally, the climactic parameters were mean
annual temperature and mean annual rain fall in the basin area.
8
Figure 1. Figure 1. Global Map of Mediterranean Biome Locations. California Mediterranean
Research Learning Center (2009).
.
9
METHODS
The twelve rivers studied were distributed as follows: two river basins from each of
the continents of Europe, Asia, North and South America, Africa and Australia
(Appendix A). Species richness was obtained by recording presence data from published
sources of fish assemblages (Appendix B), which were then counted and totaled
(Appendix A and C).
Fish species found in drainages located within the six continents
were categorized into feeding guilds: insectivores, piscivores, herbivores, omnivores,
and planktivores using diet information from www.fishdatabase.org (Appendix C).
These five feeding guilds are commonly used for trophic level classification of fish in
North America (Karr, 1986) and Europe (Griffiths, 2006). Only adult forms were taken
into consideration as feeding behavior changes during ontogeny (Brown and Matthews,
1995). The number of species found in each of the five feeding guilds were counted and
totaled to determine species richness within trophic levels (Appendix A).
Values for fish species richness were subject to several sources of error. First, the
number of fish species may be underestimated due to inadequate sampling effort or
extinctions due to human activity occurring before collections were made (Oberdorff et
al., 1995). Secondly, the number of fish species may be overestimated if some species
have been recently introduced in rivers (Moyle 2002). To minimize these potential
adverse effects upon the accuracy of the study, only the most recent references were
selected, and only fish currently found within these basins were used. Extinct fishes were
not included in this study.
10
For each drainage system the following variables were determined from the
literature (Appendix D) : (1) total surface area of the drainage basin in square kilometer
(km2), (2) mean annual discharge at the river mouth in cubic meters per second (m3/s),
(3) total surface area of the continent (km2), (4) mean annual temperate (C˚), (5) mean
annual rain fall in the area (mm), (6) glaciated area within the study basin (km2), and (7)
net primary productivity (kg2/yr) as can be seen in Table 2.
The seventh variable of net primary productivity was calculated using Lieth’s
(1975) model as applied by Golubyatnikov and Denisenko (2001) (Appendix E). As net
aquatic productivity data was difficult to obtain, mean annual air temperature and mean
annual rainfall were used to estimate average mass of terrestrial primary productivity
from Lieth’s (1975) model as demonstrated by Oberdorff et al. (1995). Terrestrial
primary productivity and aquatic primary productivity co-vary (Livingstone et al., 1982;
Oberdorff et al., 1995; Hugueny, 1989) and were used as a surrogate in this study; as seen
in previous studies (Livingstone et al., 1982; Oberdorff et al., 1995; Hugueny, 1989).
Statistical Analysis
One-way analysis of variance (ANOVA), the two-way ANOVA, the chi-squared
test, and multiple regressions were all used to assess hypotheses. One-way ANOVAs
were used to determine whether the number of trophic levels present and species richness
differed among continents. A two-way ANOVA was used to determine whether the
species richness within each trophic level differed among continents. A chi-square test
was conducted to determine if there was an association between number of species per
11
trophic level and continent. Finally, two backward elimination multiple regressions were
used to determine if there were any relationships between the independent variables total
surface area, mean annual discharge, total surface area of the continent, mean annual
temperature, mean annual rain fall in the area, and the dependent variables of species
richness and number of trophic levels present. The variable, total basin area of historical
glaciation was removed from the multiple regressions because none of these basins had
any history of glaciation (Mercer, 1983; Moyle and Herbold, 1987). After running the
multiple regressions, the San Joaquin River became an outlier. Upon further
investigation, as this river is a highly disturbed system and in fact is intermittently dry for
over 132 miles (Pereira et al., 1996), it was removed from the data set.
Species richness (total and within trophic levels) data was not normally distributed.
All attempts at transformation of these data sets were unsuccessful at obtaining normal
distribution, including squaring, taking the square root, taking the natural log, and
multiplying the data set. As a result, non-parametric tests were used and caution should
be used when interpreting the results. Data was analyzed using SPSS 17.0 software.
RESULTS
Numbers of trophic levels (trophic diversity) were statistically different among
continental locations (Table 1, Figure 2). The continents of Asia, Europe, North
America, Africa and South America had somewhat similar trophic diversity. Trophic
levels from all continents were significantly different from Australia (Figure 2). Rivers
in Africa, Asia, Europe, North America, and South America supported almost twice as
12
many trophic levels as Australia (Figure 2). Total species richness was also significantly
different among continents (Table 2, Figure 3). North America, Australia, and South
America had greater species richness then that of Asia, Europe and Africa. Across trophic
levels and continents, there were significant differences in species richness (Table 3,
Figure 4). The omnivore trophic level had the greatest number of species than any other
group (Figure 4 and 5).
The chi-square test conducted to determine a possible association between species
richness of trophic levels and continent revealed a significant difference between trophic
richness levels in the southern hemisphere and the northern hemisphere (X2 = 34.59,
df=4, P<0.001 (Figure 5).
Ecological and Historical Factors on Species Richness
Among all six factors (total surface area of the drainage basin, mean annual
discharge at the river mouth, total surface area of the continent, mean annual temperate,
mean annual rain fall, and glaciated area within the study basin) there were no
statistically significant relationships with species richness except for a weak positive
relationship with annual average discharge (Table 3, Figure 6). The San Joaquin River
was found to be the only outlier. With this outlier removed, there was a very strong
positive relationship between species richness and annual average discharge (Table 4) as
seen in Figure 7.
13
Ecological and Historical Factors on Number of Tropic Levels Present
Among all six factors of total surface area of the drainage basin, mean annual
discharge at the river mouth, total surface area of the continent, mean annual temperate,
and mean annual rain fall, there were no statistically significant relationships within
tropic levels (Table 4).
14
Trophic Level
SS
df
MS
F-value
P-value
5.417
5
1.083
4.333
0.051
1.500
6
0.250
6.917
11
229.9
Between
Continents
Within
Continents
Total
Table 1. Trophic Level ANOVA. Statistical summary of a one-way ANOVA results for between
continent effects for number of trophic levels present. This table illustrates that there is a statistically
significant difference between the numbers of trophic levels between continental locations. All
statistically significant P-values are italicized.
15
Figure 2. Trophic Level Histogram. Mean trophic level diversity of Mediterranean fresh water fish
for each continent location. Asia, Europe, North America, South America and Africa have twice as
many trophic levels occupied as Australia.
16
Species Richness
SS
Df
MS
F-value
P-value
4916.667
5
983.33
5.717
0.028
1032.000
6
172.00
5948.667
11
Between
continents
Within
Continents
Total
Table 2. Species Richness ANOVA. Statistical summary of a one-way ANOVA results for between
continent effects for species richness. This table illustrates that there is a statistically significant
difference between the numbers of trophic levels between continental locations. All statistically
significant P-values are italicized.
17
Figure 3. Species Richness Histogram. Mean species richness of Mediterranean fresh water fish for
each continent location. North America has the greatest number of species. Australia and South
America are the second most specious and have similar species richness. Asia, Europe, and Africa
are similar and have the least amount of species richness.
18
Source
SS
Df
MS
F-value
P-value
Trophic Level
4038.90
4
1009.725
49.335
P <0.001
Continent
983.33
5
196.667
9.609
P<0.001
Trophic Level*Continent
2511.50
20
125.575
6.136
P<0.001
Error
614.00
30
20.467
Total (Corr)
8147.73
59
Table 3. Continental Trophic Richness ANOVA. Statistical summary of a two-way ANOVA testing
possible interactions between tropic level, species richness and continent. This table illustrates that
there is a significant difference in species richness among both trophic levels and continents.
Additionally, there is a significant interaction between trophic level and content on species richness.
All significant P-values are italicized.
19
Figure 4. Continental Trophic Species Richness Histogram. This represents all of the species present
within the trophic levels present at each continental location.
20
Figure 5. Continental Community Composition Chart. This chart breaks down each continent into
its representative trophic levels and their contribution to total species richness.
21
Dependent
variable
Species
Richness
(SR)
Species
Richness
(SR)
Trophic
Diversity
(TD)
Parameter
R
F-value
P-value
Df
Model
Annual Average
Discharge with San
Joaquin River (AAD)
Annual Average
Discharge without San
Joaquin River (AAD)
Drainage Area
(AREA)
0.478
2.965
0.116
11
SR=0.035(AAD)+15.524
0.852
23.847
0.001
10
SR=0.058(AAD)+0.571
0.45
2.533
0.143
11
TD=4.065-1.197e^6(AREA)
Table 4. Multiple Regression on Species Richness and Trophic Diversity. This table consists of the
most descriptive factors on species richness and trophic diversity found when conducting a
backwards multiple regression on the hydrological, geological, ecological, and climactic factors.
Included are annual average discharge both with and without the San Joaquin River on species
richness, and drainages area on trophic diversity. These values had the lowest P-value of all 7 factors
measured against. Significant P values are italicized.
22
Figure 6. Species Richness Regression with the San Joaquin River. Species Richness of
Mediterranean freshwater fish for each river as a function of annual average discharge at river
mouth. This regression is illustrated with the San Joaquin River included.
23
Figure 7. Species Richness Regression without the San Joaquin River. Species richness of
Mediterranean freshwater fish for each river excluding the San Joaquin River, as a function of
annual average discharge at river mouth.
24
DISCUSSION
Freshwater fish community structure (trophic level diversity, trophic level
richness, and species richness) differed across each of the six Mediterranean biomes.
North America supported the highest levels of species richness followed by Australia and
South America; Asia, Europe, and Africa were similar and had lower species richness
(Figure 3). Australia had the least amount of species richness present (Figure 2).
Continental trophic richness differed significantly with omnivory consistently
having the highest species richness (Figure 4). Further observation revealed significant
differences between types of trophic levels present among the continental locations
specifically regarding the richness of both insectivores and piscivores between the
northern and southern hemispheres (Figure 5). The northern hemisphere had
significantly fewer insectivores than the southern hemisphere. Conversely, the northern
hemisphere had significantly more piscivores then the southern hemisphere.
The second investigation comprising this study examined differences of
community trophic diversity and species richness between the biome locations, in
addition to seeing if these differences could be explained by measurable physical
parameters such as hydrology, geology, ecology, and climate. Among all seven factors
measured, only the hydrological parameters of annual average discharge demonstrated a
positive effect upon species richness (Figure 7). No significant effects of the seven
factors on trophic diversity were found.
Historically, biogeography is the science of studying and observing patterns in
ecosystems at different spatial and temporal scales (Lamouroux, 2002). Previous studies
25
have done so by using various community properties, such as species richness and
proportional composition of trophic levels (Moyle and Herbold, 1987; Lamouroux,
2002). Such patterns expressed in community convergence are an aspect of the
hypothesis that characteristics of communities are predictable from their environment
(Schluter, 1986), and that communities are structured rather than random entities.
Models predicting similarities in community traits from independent systems having
similar environmental features suggest the existence of key repeated mechanisms
underlying community organization (Lamouroux, 2002). Therefore, while predictive
tools in ecology often site specific and poorly transferable across ecosystems (Peters and
Myers, 1991), convergence studies can provide general models for predicting
fundamental community patterns in multiple sites (Mooney and Dunn, 1970; Cody and
Mooney, 1978). This study investigated community structure across the broadly separate
geographic regions in the Mediterranean biome and then compared this structure in terms
of trophic level diversity.
The concept of trophic levels is one of the oldest ideas in ecology and helps us to
understand assemblage composition and energy flow within communities (Thompson et
al., 2007). The results of the trophic diversity analysis of this study illustrate a
prevalence of omnivory within all of the continental locations. This is not the only case
where omnivory dominates communities, a fact that has been documented in several
aquatic systems (e.g., marine, reservoirs, and estuarine) and is thought to stabilize food
webs (Emmerson and Yearsley, 2004). The importance and prevalence of omnivory for
the structure and dynamics of food webs is a long-standing controversy (Cousins, 1987;
26
Burns, 1989; Polis, 1991; Holt and Polis, 1997; Vandermeer, 2006; Thompson et al.,
2007).
Omnivory is key to the fundamental understanding of food web dynamics, and
as a result much debate has occurred over this subject (Polis and Strong, 1996; Hairston
and Hairston, 1997; Thompson et al., 2007). Current theoretical models suggest that
omnivory may in fact stabilize food webs (Emmerson and Yearsley, 2004; Thompson et
al., 2007), and that larger food webs support higher levels of omnivory (Woodward and
Hildrew, 2002; Thompson et al., 2007). This theory was evident in this study, as there
were greater numbers of species within continental locations that had higher levels of
omnivory (Figure 4 and 5). Further analysis would be required to confirm this
possibility.
The inverse proportion of piscivorous and insectivorous species richness between
the northern and southern hemisphere is not surprising as both of these families evolved
separately approximately 160 to 150 million years ago; salmonids evolved in Laurasia
while the galaxiid family evolved in Gondwanaland (Waters et al., 2000; McDowall,
2002; Clavero et al., 2005; Lévêque et al., 2008). This finding supports both the welldocumented biogeographical colonization histories of the southern and northern
hemispheres (McDowall, 2002) and the positive relationship between body size and
trophic level in fishes (see Data collected in Appendix C). Body size determines the
range of prey species a predator can consume, allowing larger individuals with larger
anatomy to feed at higher trophic levels (Winemiller, 1991; Jennings et al., 2001). The
salmonid family dominates northern hemisphere freshwater fish communities in
temperate locations, which tend to be large piscivorous fish (Jennings et al., 2001).
27
Meanwhile, in the southern hemisphere the galaxiid family dominates these same
communities, which tend to be small insectivorous fish (Reyjol et al., 2007).
While these two historical explanations of trophic level composition contribute to
understating the observed patterns, other ecological processes such as extinction,
invasion, competition, and disturbance, may also play a role in shaping these
communities.
As previously discussed, the difference in the predictive ability of varying factors
is based on the size scale of the community patterns. On the local scale, physical factors
appear to determine species richness in variable environments (Capone and Kushlan,
1991). On larger spatial scales (regional and geographical), physical factors such as area,
total discharge, and primary productivity, along with historical factors such as speciation
rates and dispersal are the major determinant of species richness, and regulate the
importance of local-scale factors (Lamoureux et al., 2002). These differences in spatial
variability in species diversity patterns are primarily explained by the three previously
introduced theories: the species-area theory (Preston, 1962), the species-energy theory
(Wright, 1983), and the historical theory (Whittaker, 1977). This study sought to try and
branch these two differing spatial scales by comparing similar a similar type of
environment across a broad geographical area, in addition to trying to determine if any of
the three aforementioned hypotheses held true for freshwater vertebrates (fishes) in
similar climates.
The results of this study indicated that annual average discharge is the most
important factor influencing freshwater fish species richness patterns globally across the
28
entire Mediterranean biome, illustrating for the Mediterranean biome that the speciesarea theory and historical theory do not explain species richness patterns. This finding is
consistent with those of Poff and Allan (1995), Oberdorff et al. (2001) and Cattanéo
(2005). These studies show that changes in annual average discharge influence the
functional organization of fish assemblages and/or demonstrated effects on species
richness. While the species-energy theory does help explain species richness across the
Mediterranean biome, additional consideration is in order since several previous studies
looking at freshwater species richness patterns have found that area, average annual
discharge, and primary productivity explained species richness (Oberdorff et al., 1995;
Guégan, 1998; Hawkins et al., 2003; Clavero et al., 2004). Nevertheless, a general
understanding of the degree of similarity of fish communities across geographical distinct
basins is lacking. This is primarily because quantitative descriptors can sometimes
become intercorreleated across basins, making it difficult to identify which factors are
responsible for community structure (Lamaroux, 2002). Using these species richness
theories as general predicative tools of community characteristics seem to initially require
precise measurements of the factors defining the community’s habitat (Lamaroux, 2002).
A better understanding of Mediterranean biome communities could be achieved by
further studies into the hydraulic nature of these basins, the effect of high disturbance of
flow regime on primary productivity, and the effect of invasive species on the native
community.
In this study, primary productivity not being a predictor of species richness could
be due to the highly disturbed nature of the riparian habitat of the Mediterranean biome.
29
As previously stated, the Mediterranean biome is one of the most altered systems in the
world. Several studies have illustrated that changes in natural stream regime affect
primary productivity (Mallin et al., 1993). All rivers in this study, as with most
Mediterranean biome rivers, have been dammed and have several water diversions. The
primary reasons for these dams are flood control, to regulate the fluctuation of water flow
throughout the year, and agricultural purposes. As in all Mediterranean biome locations,
agriculture has been a dominant feature of the terrestrial environment. This has led to the
degradation of riparian habitats and diversion of water from the rivers themselves to
irrigate vast croplands (Underwood et al., 2009). Due to the installation of these dams,
the natural hydrology of these rivers has also been altered to reflect more of a constant
flow regime rather than the cyclical flood regime that defines the Mediterranean biome
(Junk et al., 1989). The damming of a river has been called a cataclysmic event in the
life of a riverine ecosystem (Ligon et al., 1995). By changing the flow of water,
sediment, nutrients, energy, and biota, dams interrupt and alter most of a river’s
important ecological processes (Ligon et al., 1995). This could be the reason that
primary productivity in the basins studied does not reflect species richness.
CONCLUSION
The data and analysis presented here have led to the surprising conclusion that
annual average discharge is the most important factor influencing fish species richness
patterns globally across the entire Mediterranean biome. This illustrates that for the
Mediterranean biome the species-area theory and historical theory do not explain species
30
richness patterns. While the species-energy theory does help explain species richness in
the Mediterranean biome, additional consideration is in order; since several previous
studies looking at freshwater species richness patterns have found that area, average
annual discharge and primary productivity explained species richness (Oberdorff et al.,
1995; Guégan, 1998; Hawkins et al., 2003).
The Mediterranean-climate regions of the world are renowned for high levels of
richness and endemism in both flora and fauna. However, it is one of the most imperiled
ecosystems in the world, and has the highest density of human population and
agricultural practices. A fuller understanding of these freshwater Mediterranean
communities, their composition, and the factors that contribute to their survival and
enhancement will help formulate the required strategies to rehabilitate, conserve, and
protect them in the future. Armed with the knowledge that annual average discharge of
these highly endangered river basins directly influences species diversity, dam discharge
regimes can be monitored and modified to result in the desired level of species richness.
31
APPENDICES
32
Appendix B. Data
sources.
33
Location
Drainage
Drainage
Area in
Square
Kilometers
Average Annual
Discharge in
Cubic Meters
per Second
Area of
Continent in
Square
Kilometers
Average
Annual Rain
Fall in
millimeters
Average
Annual
Temperature in
Degrees
Celsius
Average
Area of
Historical
Glaciation
Species Richness
in Number of
Species
Mira
Antunes,
2008
Global Runoff
Data Center,
2010
Encyclopedia
Britannica,
2008
Magalhaes,
2002
Magalhaes,
2002
Illes,
1978;
Griffiths,
2006
Bernardo et al.,
2003
Guadiana
Clavero et
al., 2004
Global Runoff
Data Center,
2010
Encyclopedia
Britannica,
2008
Corbacho and
Sanchez,
2001
Corbacho and
Sanchez, 2001
Illes,
1978;
Griffiths,
2006
Clavero et al.,
2005
Bilga
Sari et al.,
2006
Global Runoff
Data Center,
2010
Encyclopedia
Britannica,
2008
World
Weather
Information
Service,2000
World Weather
Information
Service, 2000
Illes,
1978;
Griffiths,
2006
Sari et al., 2006
Qishon
Bar-Or,
2000
Oren et al.,
1973; Global
Runoff Data
Center, 2010
Encyclopedia
Britannica,
2008
World
Weather
Information
Service, 2000
Bar-Or, 2000
Goren and
Ortal,
1999
Oren et al., 1973;
Goren and Ortal,
1999
Sacramento
Moyle,
2002
Global Runoff
Data Center,
2010
Encyclopedia
Britannica,
2008
World
Weather
Information
Service, 2000
World Weather
Information
Service ,2000
May and
Brown,
2002
May and Brown,
2002
San
Joaquin
Moyle,
2002
Global Runoff
Data Center,
2010
Encyclopedia
Britannica,
2008
World
Weather
Information
Service, 2000
World Weather
Information
Service, 2000
Moyle,
2002
Moyle, 2002
Biobío
Gobierno
De Chile,
Direccion
General De
Aguas, 2004
Oyarzun, 1995;
Feige et al.,
2009; Global
Runoff Data
Center, 2010
Encyclopedia
Britannica,
2008
World Weather
Information
Service, 2000
Cussac et
al., 2004
Dyer, 2000
Itata
Gobierno
De Chile,
Direccion
General De
Aguas, 2004
Feige et al.,
2009; Global
Runoff Data
Center, 2010
Encyclopedia
Britannica,
2008
World Weather
Information
Service, 2000
Cussac et
al., 2004
Dyer, 2000;
Figueroa et al.,
2010
Berg
Kalejta and
Hockey,
1991
Global Runoff
Data Center,
2010
Encyclopedia
Britannica,
2008
Flügel, 1995;
World Weather
Information
Service., 2000
Cussac et
al., 2004
Livingstone et al.,
1982
Kleynhans,
1999
Global Runoff
Data Center,
2010
Encyclopedia
Britannica,
2008
Flügel, 1995;
World Weather
Information
Service, 2000
Cussac et
al., 2004
Livingstone et al.,
1982
Global Runoff
Data Center,
2010
Encyclopedia
Britannica,
2008
World Weather
Information
Service, 2000
Unmack,
2001;
Cussac et
al., 2004
Allen et al., 2002;
Morgan, 2003;
Morgan et al.,
2005; Australian
Department of
Fisheries, 2009
Global Runoff
Data Center,
2010
Encyclopedia
Britannica,
2008
World Weather
Information
Service, 2000
Unmack,
2001;
Cussac et
al., 2004
Allen et al., 2002;
Morgan, 2003;
Morgan,, 2004;
Morgan et al.,
2005; Australia
Department of
Fisheries, 2009
Europe
Asia
North
America
South
America
Africa
Orange
Murray
Walker et
al., 1993
Australia
Swan
Morgan,
2004
Oyarzun,
1995;
Gobierno De
Chile,
Direccion
General De
Aguas, 2004
World
Weather
Information
Service,
2000
Flügel, 1995;
World
Weather
Information
Service, 2000
Swanevelder,
1981; World
Weather
Information
Service, 2000
World
Weather
Simpson et
al., 1993;
Information
Service, 2000
World
Weather
Information
Service,
2000; Viney
and
Sivapalan,
2001
Appendix C. Species lists and trophic level.
34
Continent
Asia
Location
Turkey
Drainage
Bigla
Qishon
Species
Trophic
level
Species
Trophic
Level
Anguilla anguilla
Piscivore
Anguilla anguilla
Piscivore
Salmo trutta macrostigma
Omnivore
Acantghobrama lissneri
Omnivore
Oncorhynchus mykiss
Omnivore
Garra rufa
Herbivore
Leuciscus cephalus
Omnivore
Hemigrammocapoeta nana
Herbivore
Petroleuciscus borysthenicus
Omnivore
Clarias gariepinus
Omnivore
Rhodeus amarus
Herbivore
Aphanius mento
Omnivore
Phoxinus phoxinus
Omnivore
Mugil cephalus
Planktivore
Vimba vimba
Omnivore
Liza ramada
Planktivore
Chalcalburnus chalcoides
Omnivore
Orecochromis aureus
Planktivore
Barbus tauricus escherichi
Planktivore
Tilapia zillii
Herbivore
Capoeta capoeta bergamae
Planktivore
Tristamella sacra
Omnivore
Gobio gobio
Omnivore
Mugil cephalus
Omnivore
Cobitis fahirae
Omnivore
Neogobius fluviatilis
Omnivore
Mugil cephalus
Omnivore
Continent
Europe
Location
Drainage
Israel
Iberian Peninsula
Guadiana
Mira
35
Species
Trophic level
Species
Trophic level
Petromyzon marinus
Piscivore
Anguilla anguilla
Piscivore
Anguilla anguills
Piscivore
Chondrostoma lemmingii
Omnivore
Alosa alosa
Omnivore
Barbus sclateri
Omnivore
Anaecypris hispanica
Planktivore
Barbus bocagei
Omnivore
Barbus comiza
Piscivore
Chondrostoma polylepis
Planktivore
Luciobarbus microcephalus
Omnivore
Rutilus alburonides
Omnivore
Barbus sclateri
Omnivore
Mugil cephalus
Omnivore
Chondrostoma polylepis
Omnivore
Leuciscux pyrenaicus
Omnivore
Rutilus lemmingii
Omnivore
Tinca tinca
Omnivore
Tropidophoxinellus alurnoides
Omnivore
Coitis paludica
Omnivore
Gasterosteus aculeatus
Omnivore
Blennius fluviatilis
Omnivore
Oncorhynchus mykiss
Omnivore
Esox lucius
Piscivore
Carassius auratus
Herbivore
Cyprinus carpio
Omnivore
Gobio gobio
Omnivore
Lepomis gibbossus
Omnivore
Micropterus salmoides
Piscivore
Gambusia holbrooki
Insectivore
Mugil cephalus
Omnivore
Continent
North America
Location
California
Drainage
Sacramento
San Joaquin
Species
Trophic
level
Species
Trophic
level
Lampetra tridentata
Piscivore
Lampetra tridentata
Piscivore
36
Lampetra fluviatilis
Piscivore
Lampetra fluviatilis
Piscivore
Lampetra pacifica
Piscivore
Entosphenus hubbsi
Piscivore
Acipenser transmontanus
Omnivore
Acipenser transmontanus
Omnivore
Acipenser medirostris
Omnivore
Acipenser medirostris
Omnivore
Alosa sapidissima
Omnivore
Alosa sapidissima
Omnivore
Dorosoma petenese
Herbivore
Dorosoma petenese
Herbivore
Cyprinus carpio
Omnivore
Cyprinus carpio
Omnivore
Carassius auratus
Herbivore
Carassius auratus
Herbivore
Notemigonus crysoleucas
Omnivore
Notemigonus crysoleucas
Omnivore
Orthodon microlepidotus
Omnivore
Orthodon microlepidotus
Omnivore
Mylopharodon conocephalus
Omnivore
Mylopharodon conocephalus
Omnivore
Lavinia exilicauda
Omnivore
Lavinia exilicauda
Omnivore
Ptychocheilus grandis
Piscivore
Ptychocheilus grandis
Piscivore
Gila bicolor
Omnivore
Pogonichthys macrolepidotus
Omnivore
Pogonichthys macrolepidotus
Omnivore
Hesperoleucus symmetricus
Omnivore
Hesperoleucus symmetricus
Omnivore
Hesperoleucus symmetricus
Omnivore
Rhinichthys osculus
Omnivore
Rhinichthys osculus
Omnivore
Richardsonius egregius
Omnivore
Notemigonus crysoleucas
Omnivore
Notemigonus crysoleucas
Omnivore
Pimephales promelas
Herbivore
Pimephales promelas
Herbivore
Catostomus occidentalis
Herbivore
Catostomus planyrhynchus
Herbivore
Ictalurus furcatus
Omnivore
Catostomus occidentalis
Herbivore
Ictalurus punctatus
Omnivore
Ictalurus furcatus
Omnivore
Ictalurus catus
Piscivore
Ictalurus punctatus
Omnivore
Ictalurus nebulosus
Omnivore
Ictalurus catus
Piscivore
Ictalurus melas
Omnivore
Ictalurus nebulosus
Omnivore
Hypomesus transpacificus
Planktivore
Ictalurus melas
Omnivore
Hypomesus nipponensis
Omnivore
Hypomesus transpacificus
Planktivore
Spirinchus thaleichthys
Omnivore
Hypomesus nipponensis
Omnivore
Oncorhynchus kisutch
Planktivore
Spirinchus thaleichthys
Omnivore
Oncorhynchus tshawytscha
Omnivore
Oncorhynchus kisutch
Planktivore
Oncorhynchus mykiss
Omnivore
Oncorhynchus tshawytscha
Omnivore
Oncorhynchus keta
Omnivore
Oncorhynchus mykiss
Omnivore
Oncorhynchus gorbuscha
Omnivore
Oncorhynchus keta
Omnivore
Oncorhynchus nerka
Planktivore
Oncorhynchus gorbuscha
Omnivore
Salmo trutta
Omnivore
Oncorhynchus nerka
Planktivore
Salvelinus fontinalis
Omnivore
Salmo trutta
Omnivore
Salvelinus namaycush
Omnivore
North America con’t
Continent
Location
California
Drainage
Sacramento
San Joaquin
Salvelinus namaycush
Omnivore
Lucania parva
Omnivore
Salvelinus fontinalis
Omnivore
Salvelinus confluentus
Omnivore
Lucania parva
Omnivore
Menidia beryllina
Planktivore
Gambusia affinis
Omnivore
Gasterosteus aculeatus
Omnivore
37
Menidia beryllina
Planktivore
Morone saxatilis
Omnivore
Gasterosteus aculeatus
Omnivore
Morone chrysops
Piscivore
Morone saxatilis
Omnivore
Archoplites interruptus
Omnivore
Morone chrysops
Piscivore
Pomoxis nigromaculatus
Omnivore
Archoplites interruptus
Omnivore
Pomoxis annularis
Piscivore
Pomoxis nigromaculatus
Omnivore
Lepomis gulosus
Omnivore
Pomoxis annularis
Piscivore
Lepomis cyanellus
Omnivore
Lepomis gulosus
Omnivore
Lepomis macrochirus
Omnivore
Lepomis cyanellus
Omnivore
Lepomis gibbosus
Omnivore
Lepomis macrochirus
Omnivore
Lepomis microlophus
Omnivore
Lepomis gibbosus
Omnivore
Micropterus salmoides
Omnivore
Lepomis microlophus
Omnivore
Micropterus punctulatus
Omnivore
Micropterus salmoides
Omnivore
Micropterus dolomieui
Omnivore
Micropterus punctulatus
Omnivore
Micropterus coosae
Omnivore
Micropterus dolomieui
Omnivore
Perca flavescens
Omnivore
Micropterus coosae
Omnivore
Percina macrolepida
Omnivore
Perca flavescens
Omnivore
Hysterocarpus traski
Omnivore
Percina macrolepida
Omnivore
Eucyclogobius newberryi
Omnivore
Hysterocarpus traski
Omnivore
Acanthogobius flavimanus
Omnivore
Eucyclogobius newberryi
Omnivore
Tridentiger bifasciatus
Omnivore
Acanthogobius flavimanus
Omnivore
Leptocottus armatus
Omnivore
Tridentiger bifasciatus
Omnivore
Cottus asperrimus
Omnivore
Leptocottus armatus
Omnivore
Cottus gulosus
Omnivore
Cottus asperrimus
Omnivore
Planktivoretichthys stellatus
Omnivore
Cottus gulosus
Omnivore
Mugil cephalus
Omnivore
Planktivoretichthys stellatus
Omnivore
Mugil cephalus
Omnivore
Continent
South America
Location
Central Chile
Drainage
Central Chile
Biobio
Itata
Species
Trophic level
Species
Trophic level
Ameiurus melas
Omnivore
Ameiurus melas
Omnivore
Ameiurus nebulosus
Omnivore
Ameiurus nebulosus
Omnivore
Ancistrus erinaceus
Herbivore
Ancistrus erinaceus
Herbivore
Australoheros facetus
Omnivore
AustraloHerbivoreos facetus
Omnivore
Basilichthys australis
Omnivore
Basilichthys australis
Omnivore
38
Basilichthys microlepidotus
Omnivore
Basilichthys microlepidotus
Omnivore
Brachygalaxias bullocki
Omnivore
Brachygalaxias bullocki
Omnivore
Brachygalaxias gothei
Omnivore
Brachygalaxias gothei
Omnivore
Bullockia maldonadoi
Omnivore
Bullockia maldonadoi
Omnivore
Carassius auratus auratus
Omnivore
Carassius auratus auratus
Omnivore
Carassius carassius
Omnivore
Carassius carassius
Omnivore
Cheirodon australe
Herbivore
Cheirodon australe
Herbivore
Cheirodon galusdai
Herbivore
Cheirodon galusdai
Herbivore
Cheirodon interruptus
Planktivore
Cheirodon interruptus
Planktivore
Cheirodon kiliani
Omnivore
Cheirodon kiliani
Omnivore
Cheirodon Piscivoreiculus
Herbivore
Cheirodon iculus
Herbivore
Cnesterodon decemmaculatus
Omnivore
Cnesterodn decemmaculatus
Omnivore
Cyprinus carpio carpio
Omnivore
Cyprinus carpio carpio
Omnivore
Diplomystes camposensis
Omnivore
Diplomystes camposensis
Omnivore
Diplomystes chilensis
Omnivore
Diplomystes chilensis
Omnivore
Diplomystes nahuelbutaensis
Herbivore
Diplomystes nahuelbutaensis
Herbivore
Galaxias globiceps
Omnivore
Galaxias globiceps
Omnivore
Gambusia affinis
Omnivore
Gambusia affinis
Omnivore
Lepomis gibbosus
Omnivore
Lepomis gibbosus
Omnivore
Nematogenys inermis
Omnivore
Nematogenys inermis
Omnivore
Odontesthes brevianalis
Omnivore
Odontesthes brevianalis
Omnivore
Odontesthes gracilis
Omnivore
Odontesthes gracilis
Omnivore
Odontesthes hatcHerbivorei
Omnivore
Odontesthes hatcHerbivorei
Omnivore
Odontesthes mauleanum
Omnivore
Odontesthes mauleanum
Omnivore
Odontesthes wiebrichi
Omnivore
Odontesthes wiebrichi
Omnivore
Orestias agassizii
Herbivore
Orestias agassizii
Herbivore
Orestias ascotanensis
Omnivore
Orestias ascotanensis
Omnivore
Orestias chungarensis
Omnivore
Orestias chungarensis
Omnivore
Orestias laucaensis
Omnivore
Orestias laucaensis
Omnivore
Orestias parinacotensis
Omnivore
Orestias parinacotensis
Omnivore
Orestias piacotensis
Planktivore
Orestias piacotensis
Planktivore
39
Continent
Africa
Location
South Africa
Drainage
Orange
Berg
Species
Trophic level
Species
Trophic level
Austroglanis sclateri
Omnivore
Pseudobarbus phlegethon
Insectivore
Barbus aeneus
Omnivore
Oncorhynchus mykiss
Omnivore
Barbus anoplus
Omnivore
Pseudobarbus burgi
Omnivore
Barbus hospes
Omnivore
Sandelia capensis
Omnivore
Barbus kimberleyensis
Piscivore
Calaxias zebratus
Planktivore
Barbus pallidus
Omnivore
Micropterus dolomieu
Omnivore
Barbus trimaculatus
Omnivore
Lepomis macrochirus
Omnivore
Clarias gariepinus
Omnivore
Labeo umbratus
Herbivore
Labeo capensis
Herbivore
Liza richardsonii
Planktivore
Labeo umbratus
Herbivore
Mugil cephalus
Omnivore
Liza richardsonii
Planktivore
Mesobola brevianalis
Planktivore
Mugil cephalus
Omnivore
Pseudobarbus quathlambae
Insectivore
Tilapia rendalli
Herbivore
Tilapia sparrmanii
Herbivore
Cyprinus carpio
Omnivore
Oreochromis mossambicus
Herbivore
Pseudobarbus quathlambae
Insectivore
Continent
Location
South Africa
Australia
Southern Australia
South Western Australia
40
Drainage
Darling-Murray
Swan-Avon
Species
Trophic level
Species
Trophic level
Retropinna semoni
Omnivore
Lepidogalaxias salamandroides
Omnivore
Mugil cephalus
Omnivore
Galaxias occidentalis
Omnivore
Percichthys chilensis
Omnivore
Percichthys chilensis
Omnivore
Percichthys melanops
Omnivore
Percichthys melanops
Omnivore
Galaxias fuscus
Insectivore
Galaxiella munda
Insectivore
Nematalosa erebi
Omnivore
Galaxiella nigrostriata
Insectivore
Hypseleotris spp
Omnivore
Tandanus bostocki
Omnivore
Galaxias brevipinnis
Omnivore
Bostockia porosa
Omnivore
Galaxias maculatus
Insectivore
Nannatherina balstoni
Omnivore
Pseudaphritis urvillii
Omnivore
Nannatherina vittata
Omnivore
Craterocephalus amniculus
Omnivore
Mugil cephalus
Omnivore
Melanotaenia splendida tatei
Omnivore
Pseudogobius olorum
Omnivore
Philypnodon macrostomus
Insectivore
Macquaria colonorum
Omnivore
Galaxias rostratus
Insectivore
Philypnodon grandiceps
Omnivore
Tandanus tandanus
Omnivore
Macquaria ambigua ambigua
Piscivore
Neosilurus hyrtlii
Omnivore
Tasmanogobius lasti
Omnivore
Anguilla reinhardtii
Omnivore
Macquaria australasica
Omnivore
Galaxias olidus
Omnivore
Maccullochella peelii peelii
Omnivore
Melanotaenia fluviatilis
Insectivore
Craterocephalus fluviatilis
Omnivore
Gadopsis marmoratus
Omnivore
Anguilla australis
Insectivore
Afurcagobius tamarensis
Omnivore
Mordacia mordax
Piscivore
Bidyanus bidyanus
Omnivore
Herbivoreinosoma microstoma
Omnivore
Mogurnda adspersa
Piscivore
Nannoperca australis
Omnivore
Leiopotherapon unicolor
Omnivore
Australia con’t
Southern Australia
Continent
Location
Darling-Murray
Drainage
Species
Trophic level
41
Cyprinus carpio
Omnivore
Salvelinus confluentus
Omnivore
Carassius auratus
Omnivore
Misgurnus anguillicaudatus
Omnivore
Oncorhynchus mykiss
Omnivore
Perca fluviatilis
Omnivore
Rutilis rutilis
Omnivore
Tinca tinca
Omnivore
42
43
44
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