Zoogeography

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Zoogeography

• FAS 1450
• Fall 2009

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Zoogeography - the study of the distributions of
animal taxa over the surface of the earth
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Fish Fauna of the Great Lakes

• 1. Who are they?
• 2. Where did they come from?
• 3. What is the nature of the interactions among
  species?

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1. Who are they? - How many are there?

• Low diversity
• Native 157 species
• Introduced 22 species
• TOTAL 179 species

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Comparison with other fish faunas

• Laurentian Great Lakes 179 species
• Coral Reefs gt 150 on 1 coral head
• Mississippi River Basingt 330 species
• Amazon River Basin gt 2,000 species
• African Great Lakes gt 450 species ENDEMIC in one
  lake!

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Why is diversity low?
Temperature
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Why is diversity low?
Temperature Productivity
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Why is diversity low?
Temperature Productivity Age
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Why is diversity low?
Temperature Productivity Age Connections - to
other lake and river basins
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1. Who are they? - Two ecological groupings

• Coldwater, deep lake group

• Coolwater, shallow basin group

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1. Who are they? - Two ecological groupings

• Coldwater, deep lake group
• lake trout
• lake whitefish
• lake herring
• lake sturgeon
• deepwater sculpin
• deepwater ciscos

• Coolwater, shallow basin

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1. Who are they? - Two ecological groupings

• Coldwater, deep lake group
• lake trout
• lake whitefish
• lake herring
• lake sturgeon
• deepwater sculpin
• deepwater ciscos

• Coolwater, shallow basin
• yellow perch
• walleye
• white bass
• channel catfish
• northern pike
• smallmouth bass

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1. Who are they? - A New Group Introduced species

• Intentional introductions
• Common carp, brown trout, steelhead, chinook and
  coho salmon

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Introduced species
Intentional introductions Common carp, brown
trout, steelhead, chinook and coho
salmon Accidental introductions Alewife, sea
lamprey, white perch, pink salmon, rainbow smelt,
round goby, ruffe
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2. Where did the native species come from?

• Endemic species
• Immigrant species

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2. Where did the native species come from?

• Endemic species
• species evolved in the system and are unique to
  the system
• Blue pike (walleye subspecies)
• Deepwater ciscos

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2. Where did the native species come from?

• Immigrant Species
• species that evolved elsewhere and entered the
  system from other watersheds
• Mississippi Basin 79 of fauna
• Atlantic drainages 9 of fauna
• Both 12 of fauna

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3. What is the nature of the interactions among
species?

• Predator-Prey relations
• Niche partitioning (generalists vs. specialists)
• Resilient species (to heavy fishing pressure or
  predation pressure)
• Sensitive species (to heavy fishing pressure or
  predation pressure)

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3. What is the nature of the interactions among
species?

• Effects of introduced species
• sea lamprey
• Parasites on large fish - lake trout are small
  compared with their ocean hosts
• Cause high mortality on lake trout
• Best opportunity for control is in reproductive
  and larval stages - concentrated in rivers

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3. What is the nature of the interactions among
species?

• Effects of introduced species
• rainbow smelt and alewife - planktivores
• compete with native planktivores
• prey on larvae of native fish species
• prey on and compete with each other!

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3. What is the nature of the interactions among
species?

• Effects of introduced species
• gobies ruffe - benthic fishes
• new immigrants to system
• ballast water introductions of 1980s
• potential to be competitors and predators on
  benthic fishes and invertebrates

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Zoogeography of Marine Fishes

• Ch. 26 in Moyle Cech

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Barriers to Dispersal in Marine Systems

• Continents - e.g. Atlantic vs. Pacific faunas
• Temperature - e.g. tropical vs. temperate vs.
  polar
• Salinity - e.g. estuaries, freshwater (Panama
  Canal)
• Depth - deep-dwelling fishes can be isolated by
  submerged mountain ranges

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Mechanisms for Dispersal in Marine Fishes

• Directed movements (e.g., with changes in
  temperature migrations)
• Pelagic eggs/larvae - current-born dispersal
• Human action - transplants (e.g., striped bass,
  American shad in Pacific Ocean 250 species
  introduced into San Francisco Bay)

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Zoogeographic Groupings of Marine Fishes

• Continental Shelf (neritic) -
• 45 of all fishes
• Tropical Zone
• Temperate (North South) Zones
• Arctic/Antarctic Zones
• Pelagic
• Abyssal

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Zoogeographic Groupings of Marine Fishes

• Pelagic -
• Epipelagic (1.3 of all fish species)
• Meso- Bathypelagic (5 of all fish species)
• Arctic
• Temperate
• Subtropical
• Tropical

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Zoogeographic Groupings of Marine Fishes

• Continental Shelf (neritic)
• Pelagic
• Deep benthic (abyssal)
• 6.5 of all fish species
• little known about these

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Example Distribution of pelagic piscivores in
north Pacific Ocean

• Arctic
• Arctic char, pink salmon, some cods
• distributed north of 0 isotherm
• North Temperate
• North Subtropical
• Tropical

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Example Distribution of pelagic piscivores in
north Pacific Ocean

• Arctic
• North Temperate
• coho, chinook, steelhead, sockeye, chum salmon
• north of 14 isotherm, south of 0 isotherm
• North Subtropical
• Tropical

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Example Distribution of pelagic piscivores in
north Pacific Ocean

• Arctic
• North Temperate
• North Subtropical
• some tunas, marlins, basking sharks, mackerel
  sharks
• north of 20 isotherm, south of 14 isotherm
• Tropical

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Example Distribution of pelagic piscivores in
north Pacific Ocean

• Arctic
• North Temperate
• North Subtropical
• Tropical
• flying fish, tunas, whale sharks, marlins
• south of 20 isotherm in northern hemisphere and
  north of 20 isotherm in southern hemisphere

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Ecology of Coral Reef Fishes

• Chapter 33
• Moyle Cech

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Distribution of Coral Reef Ecosystems

• Found in Tropical and subtropical oceans
• Mean annual temperature gt 20? C
• Influenced by currents
• e.g., Gulf Stream brings warm Caribbean water to
  mid-Atlantic
• corals and coral reef fishes are found as far
  north as Bermuda (32 North)

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Diversity of fish assemblages in Coral Reef
Ecosystems

• Indo-West Pacific 3000 species
• Great Barrier Reef 1200 species
• Western Atlantic Caribbean
• 1200 species
• Eastern Pacific lt 800 species
• Eastern Atlantic lt 500 species

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Diversity of fish assemblages in Coral Reef
Ecosystems

• Western Atlantic Caribbean
• 1200 species
• Bahamas 560 species
• San Salvador Island, Bahamas 300 - 400 species
• Dump Reef, San Salvador Island, Bahamas gt
  120 species

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How did diversity originate?

• Uncertain, but these factors probably important
• Time long evolutionary record of coral reef
  systems
• Productivity high!!
• Temperature rapid growth rates, short generation
  times of coral reef systems

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How did diversity originate?

• Probable important factors, cont.
• Complexity highly complex physical structure of
  reef
• Size small size of many species (highest
  diversity in the gobies and blennies - many lt 50
  mm at maturity
• Niche specialization high degree of specificity
  to habitat and diet
• Mechanisms of isolation?

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How does diversity persist?(how do so many
species get along with out competitive exclusion
kicking in?)

• Competition hypothesis
• all species are specialists resulting from past
  competition - suggests equilibrium (saturation)
  state
• Recruitment limitation hypothesis
• Predation hypothesis

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How does diversity persist?(how do so many
species get along with out competitive exclusion
kicking in?)

• Competition hypothesis
• Recruitment limitation hypothesis
• resources are not limiting, survival to
  settlement is limited, chance of settlement is
  rare and random - lottery hypothesis
• Predation hypothesis

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How does diversity persist?(how do so many
species get along with out competitive exclusion
kicking in?)

• Competition hypothesis
• Recruitment limitation hypothesis
• Predation hypothesis
• Predation intensity is high on young fish, few
  survive to colonize, resulting in random species
  assemblages

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Zoogeography of Freshwater Fishes
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Overview

• Unique aspects of piscine zoogeography
• longer period of record (since 350 mybp)
• constraints to dispersal in aquatic habitats
  (land masses)
• unique dispersal mechanisms - current movement of
  planktonic eggs larvae

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Interpretation of distribution patterns requires

• Ecological information - e.g., can the fish taxa
  tolerate exposure to fresh water or salt water
• freshwater dispersants - e.g., minnows - cannot
  tolerate any salinity
• Saltwater dispersants - freshwater fishes that
  can tolerate salinity - e.g., cichlids

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Interpretation of distribution patterns requires

• Geological information - what have been the past
  connections between water bodies
• past and present watershed configurations
  important - e.g. previous connections between
  Great Lakes basin and Mississippi River - 79 of
  fishes in GL Basin originated from Mississippi
  basin

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Interpretation of distribution patterns requires

• Geological information - continental drift
• a single continent (Pangaea) existed as recently
  as Triassic (200 mybp)
• Pangaea split into two continents at end of
  Triassic (180 mybp)
• Northern continent - Laurasia (modern Eurasia
  North America
• Southern continent - Gondwana (modern Africa,
  South America, Australia, Antarctica, India)

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Interpretation of distribution patterns requires

• Geological information - continental drift
• Gondwana split in Jurassic Cretaceous
• Australia broke off first
• South America broke off later
• Several fish taxa are present only on southern
  continents
• lungfishes - Australia, S. America, Africa
• cichlids - S. America, Africa, India
• characins - S. America, Africa

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Interpretation of distribution patterns requires

• Geological information - continental drift
• Laurasia split in Jurassic (120 mybp)
• North America separated from Eurasia
• Several fish taxa are present only on northern
  continents
• Cyprinids (also have moved into Africa recently)
• Percids - Holarctic (in N. America Eurasia)
• Catostomids - Nearctic (largely in N. America)
• Centrarchids - Nearctic (only in N. America)
• Cobitids - Palearctic (only in Eurasia)

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Mississippi Basin Fauna illustrates these
patterns well

• Contains 330 species, 13 families
• Basin is ancient - present arrangement since
  Rocky Mtns. formed in Tertiary (65 mybp)
• Ancient relics are extant today - have benefited
  from persistence of the basin
• Chondrosteans - sturgeons, paddlefish
• gars, bowfins
• mooneyes, pirate perch, cavefishes - only found
  here

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Mississippi Basin Fauna illustrates these
patterns well

• New taxa originated and/or flourished here
• Notropis/Cyprinella minnows (shiners)
• Etheostoma/Percina percids (darters)
• ictalurids (catfishes), especially Noturus -
  madtoms
• centrarchids, especially Lepomis (sunfishes)
• catostomids, especially Moxostoma (redhorses)

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Why is the Mississippi fauna so diverse?

• Provided a refuge from glaciers, due to
  north-south axis - taxa could retreat south as
  glaciers moved south

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Why is the Mississippi fauna so diverse?

• Provides a diversity of habitats
• Different stream types
• Coastal plain (Gulf of Mexico margin)
• Interior highlands
• Ozarks
• Tennessee/Kentucky plateau
• Interior lowlands
• Western (Missouri River basin)
• Central (Upper Mississippi River basin)
• Eastern (Ohio River basin)

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Why is the Mississippi fauna so diverse?

• Provides a diversity of habitats
• Speciation requires isolation - offered by these
  diverse AND separated habitat types
• e.g., Ozark fauna is unique from the
  Tennessee/Kentucky fauna, even though the
  habitats are similar - the Mississippi River
  valley separates them - no passage possible
  between for small taxa like darters, minnows,
  madtoms

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Why is the Mississippi fauna so diverse?

• Provides a diversity of habitats
• Species dependent on small, headwater streams are
  more easily isolated, and therefore are the most
  diverse groups
• shiners
• darters
• madtoms