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					            Riverine Habitats
• Rivers strongly influence the
  surrounding landscape by seasonal
  flooding (up to 15m is not uncommon),
  supplying a constant water during the
  dry season, altering the microclimate
  (e.g. gallery forests), and providing a
  variety of habitats in the landscape (e.g.
  swamps, marshes, streams, oxbow lakes,
  and river islands)
Riverine Habitats
            Riverine Habitats
• The Orinoco River is long (2,560km),
  flowing northeast from the Rio Guaviare
  in eastern Columbia, bisecting Venezuela
  before exiting to the Atlantic Ocean
• Although the Orinoco Basin is large, it is
  still 1/6 the Amazon
• It largely drains the Guianan Shield
Riverine Habitats
            Riverine Habitats
• The Orinoco is largely a seasonal river
  (15m variation not uncommon with flow
  decreasing to 1/25 of the highest flow)
• It bisects two distinct geologic areas
• The right (S) is Precambrian from the
  Guianan Sheild (old) and the left (N)
  bank is geologically young, forming from
  sediments from the Andes
           Riverine Habitats
• These difference extend into the
  tributaries with N being more stable,
  constrained by bedrock and filled with
  rapids and waterfalls
• Te S tributaries are unstable, with
  shifting channels formed from alluvial
  deposits
             Riverine Habitats
• The Amazon River starts
  in central Peru at the
  base of the Andes and
  drains the Maranon,
  Ucayali, and Tigre (which
  themselves are
  conglomerates of several
  smaller rivers)
• In Brazil, east of Manuas
  is Solimões
            Riverine Habitats
            Gee-Whiz Facts
• Once outside the Andes, it has
  remarkably little drop (1.5cm/km)
  through the remaining 6,696km
• Although Nile is slightly longer, the
  Amazon carries a full 16% of the world’s
  river water (the delta is 320 km wide)
  and discharges 4.5 trillion gallons/day
  (or 7.1 M cubic feet per second)
• 4.4x the Congo (2nd highest in the world)
            Riverine Habitats
             Gee-Whiz Facts
• The muddy water can be seen as far as
  100km out to see (and can be tracked to
  Africa by NASA’s ‘color scanner’
             Riverine Habitats
              Gee-Whiz Facts
• The river itself is 10km wide as far as
  1,600km up river and large ships can
  migrate 3,700km (reaching Iquitos)
• Two tributaries, the Negro and Madeira
  rank as the 5th and 6th largest rivers in
  the world themselves!
• The MS ranks 10th and has 1/12th the
  annual discharge of the Amazon
            Riverine Habitats
• In relatively recent geologic history
  (say 15MYA), the Amazon flowed
  eastward
• Why did it shift?
• Many tree species and such were
  dispersed (involuntarily) eastward
            Riverine Habitats
           Amazon Flood Cycle
• You can stand on banks of the Amazon
  during the rainy season and watch the
  water drop 1m/day. Why?
• The drainage is so large, it becomes
  relatively complex in that in some parts
  it is dry and others very wet
• E.g. rainy season in S. Amazonia O-A, in
  Manuas N-May, N basin A-June
            Riverine Habitats
           Amazon Flood Cycle
• Consequently, you can have flooding on
  one side of the Amazon as the water is
  low on the other
• Overall the pulses are relatively
  constant (as in discharge), although the
  source of said water is variable
• The relatively flat Amazon results in
  large sediment build up on the banks
           Riverine Habitats
          Amazon Flood Cycle
• When floods break through these
  levees, large lakes and swamps form
  (approximately 100,000 km2 in Amazon)
• Floods can bring water deep and wide
• Water can be 7-15m deep and penetrate
  20km into the floodplain
• Is this good?
           Riverine Habitats
• The river system is dynamic and creates
  many riverine habitats
            Riverine Habitats
• Open Rivers
• Relatively little wildlife obvious
            Riverine Habitats
• Riverine and stream
  edge
• For wildlife, it is better
  to get into some of the
  smaller tributaries
• Also a unique habitat
  for plant species
            Riverine Habitats
• Riverine and stream edge
• For wildlife, it is better to get into
  some of the smaller tributaries
• Also a unique habitat for plant species
           Riverine Habitats
• Beaches and Sandbars
• There is a tremendous amount of
  sediment washed from the Andes and
  deposited along the river edge or as
  sandbars
           Riverine Habitats
• Many shorebirds take advantage of this
  habitat
           Riverine Habitats
• Sandbar Scrub
• Good soil (coming
  from the Andes)
  does not stay
  uninhabited very
  long
           Riverine Habitats
• River Islands
• there are places in the Amazon islands
  are so dense you cannot see across
• Once the vegetation on sandbars
  stabilizes, they can easily grow
• These are very popular with human
  inhabitants…Why?
Riverine Habitats
           Riverine Habitats
• River inhabitants (ribereños) actively
  manage these islands removing
  undesirable exotics, cultivating
  desireables (e.g. cacao, mango, rubber
  trees), and removing firewood
• They also are active agriculturalists
  planting many species of ag crop
            Riverine Habitats
• Oxbows (resacas) provide another
  aquatic habitat (stagnation can occur)
Current Amazon
Riverine Habitats
           Riverine Habitats
• Floating Meadows
• There are giant floating masses of
  grasses on large rivers
• Largely ephemeral
            Riverine Habitats
• Swamps (a woody
  vegetation that is
  innundated by standing
  water for a significant
  portion of the year)
• Most have limited sp
  richness..Why?
Riverine Habitats
                   Riverine Habitats
• There are several other bird species
  which have become ‘moriche specialists’
• M oriole, sulphury flycatcher, f-t palm swift, point-t palmcreeper
           Riverine Habitats
• Floodplain Forests within the Amazon
  Basin cover 150,000km2 (e.g. FL)
• May border any type of river (which will
  influence the soil quality of forest)
• Fish are important fruit and seed
  consumers (and dispersers)
           Riverine Habitats
• Many species are restricted to
  floodplain forests
               Riverine Habitats
• Floodplain Forest is a relative term
  –   Permanently water-logged swamp (oxbow)
  –   Seasonally water-logged swamp (oxbow…)
  –   Lower floodplain (low, but recognizable for)
  –   Middle floodplain (tall for, occ flooded)
  –   Upper floodplain (tall for, rarely flooded)
  –   Old floodplain (within last 200 yrs)
  –   Previous floodplain (ancient floodplain)
            Riverine Habitats
            Natural History
• Many wildlife species
  directly depend on
  riverine habitats
• It is estimated that
  15% of nonaquatic
  Amazonian birds are
  directly dependent
  upon riverine
  habitats
            Riverine Habitats
            Natural History
• The fish diversity of the Amazon is
  tremendous
• Consider 2,400 sp (with 800 more likely
  there and not described)
• E.g. Tocantis (34 of 72 unnamed)
• Almost 40% in two groups: characins
  and catfish
              Riverine Habitats
              Natural History
• characins
            Riverine Habitats
            Natural History
• Catfish
            Riverine Habitats
            Natural History
• Other interesting
  fish
• Piranha can be
  somewhat
  controlled by the
  use of ‘timbo’, a
  local plant
  containing rotenone
            Riverine Habitats
            Natural History
• Other scary fish…
           Riverine Habitats
• Interesting Fish
• Pirarucu         lungfish   arawana
           Riverine Habitats
• Around 200sp are fruit/seed eaters
• Tambaqui (a characin) eat fruit (not
  seeds…why?) exclusively for 5 mo
                      • Breed in black
                        water, juveniles
                        live in whitewater
                        feeding on
                        zooplankton
          Riverine Habitats
• Aquatic Mammals
Riverine Habitats
           Riverine Critters
• Giant Otter (1.5m)
• Frequent oxbow lakes
• Mean carnivores
            Riverine Critters
• Capybaras (1.2m 55kg) are ecological
  equivalents to hippos
• Food source for
  caimen, jaguars,
  anacondas
            Riverine Critters
• Anaconda (not a good pet)
• Can reach 10m
            Riverine Critters
• Crocodilians (9sp in
  Neotropics)
• There are caimans and
  alligators
• Many enemies as juveniles,
  only humans as adults
• Throughout the Amazon
• Can impact food chain
            Riverine Critters
• Turtles found in the Amazon belong to a
  family of side-necked turtles
  (Pelomedusidae)
            Riverine Critters
• Giant Arran turtles can be found on
  river banks
• Considered end
  due to overhunting
             Riverine Birds
• Going down (or up) the river, you could
  see 4 sp of vultures soaring, hawks,
  caracaras, and falcons perched in trees,
  flocks of parakeets, parrots and macaws
  flying overhead
             Riverine Birds
• The hoatzin may be the most unique
  bird on the river
• Found in slow backwaters
• Poor fliers
• Usually in groups
• Folivores
• Claws and escape
             Riverine Birds
• Sunbittern hunt small aquatic insects,
  vertebrates, and crustaceans
• Only sp in family
             Riverine Birds
• Three sp of screamers are in slow
  waters
• Related to ducks
• Excellent fliers
             Riverine Birds
• Storks, herons and egrets
             Riverine Birds
• Chestnut-bellied heron, elegant capped
  heron & tiger heron(s)
             Riverine Birds
• Boat-billed Heron is an
  odd bird of the
  mangroves and
  riverbanks
• A noctural heron, bill
  may be sensitive
              Riverine Birds
• Eight sp (2 Neotropical) of
  jacana (Charadriiformes)
  walk delicately on lily pads
  in marshlands and
  riversides
• Only males incubate eggs
             Riverine Birds
• Kingfishers are one of
  the most visible birds
  on the rivers
• 5 sp in 5 sizes
  38, 28, 23, 20, 14cm
• Their odd shape make
  them rather
  distinctive
             Riverine Birds
• The 16 jacamars (Piciformes) are
  exclusively Neotropical (green or brown)
• While many nest in riverbanks, some
  nest in termite mounds
• Sally

				
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