IN WETLAND ECOSYSTEM
Livi Wilson and Jitendra Kumar
College of Fisheries, KVAFSU, Mangalore, Karnataka
The study of the structure of feeding relationships
among organisms in an ecosystem
Feeding or trophic relationships can be represented
Food webs depict
trophic links between
all species sampled in
food chains simplify
this complexity into
linear arrays of
FOOD WEBS IN SPECIFIC WETLAND TYPES
Producers in a salt marsh include
various other salt tolerant plants
THE CONSUMERS COME IN SEVERAL CATEGORIES
ACCORDING TO THEIR PREFERRED HABITAT.
periwinkle snails that travel up and down plants,
a. Aerial Habitat--- above the substrate, not that in
the air necessarily
Consumers -- spiders and insects that live on plant leaves,
Detrital food web
< 10% of the above ground primary productivity in a
saltmarsh actually gets grazed,. Most plant biomass
dies and decays and is passed through the detrital
consumers --- bacteria and fungi.
These are then consumed by the smallest
animals—worms, copepods, rotifers, larval stages
of benthic invertebrates, in other words, plankton.
The bigger benthic invertebrates are either
scavengers (crabs, snails) or filterers (oysters,
overlaps with the benthic habitat,
Consumers --- vertebrates.
There are several species of resident fish such as
silversides, killifish, and mummichogs
In fact about 90% of the commercially important
fish and shellfish in the southeast Atlantic and Gulf
coasts depend on marshes.
includes many ducks and wading birds.
Like the fish, many of these depend on marshes
along their migration routes and are not year round
Raccoons and muskrats use salt marshes
extensively as a food source
Because of the salt, there is less variety of
PRODUCERS --- , but very high biomass because
of the constant tidal influx of nutrients.
CONSUMERS--- wide variety of consumers present
especially filter feeders and detritivores. Barnacles
and oysters filter feed and fiddler crabs scavenge,
among lots of other invertebrates, especially
juveniles. These juveniles include the commercially
important spiny lobster, shrimp, mullet, and tarpon.
These all provide food for a vast array of wading
3. FRESHWATER MARSHES
Reed grasses, cattails, rice, sedges, and ragweed
are common to most temperate freshwater
marshes, although distribution varies with latitude.
wetlands that are the most affected by "alien
Eg:The water hyacinth,
is a trouble maker,
it is very good at water filtering and then holding
onto the excess nutrients or chemicals. Thus it's
often suggested as a valuable addition to natural
wastewater treatment programs
CONSUMERS---The most abundant invertebrates
are true flies, including mosquitoes.
With a high diversity of invertebrates there is a high
diversity of birds
The dominant plant ---Sphagnum moss. It grows in
cushionlike spongy mats with very high water
Sphagnum moss can hold 15-23 times its dry
weight in water. The moss only grows actively at
the surface, and the lower layers die off and
decompose into peat
. Other plants may include heathers, cranberry,
blueberry, some pines, spruce, and tamarack trees
Peatlands ---wetlands having the lowest
lowest nutrient levels .
hence several carnivorous plants are found here.
They get their extra nutrients from insects.
Animal density is fairly low
because they are acidic and not much eats moss.
They do serve as trails and shelters for large
Lots of birds pass through these areas on their
: sandhill cranes, short-eared and great gray owls,
. SOUTHERN DEEPWATER SWAMPS
Cypress and tupelo trees dominate these
There is a high diversity and high biomass
oƒ invertebrates which depend on the abundant
detritus available. Once again, this is the major
source of nutrients for the food web
Reptiles and amphibians are quite diverse because
they can adapt to changing flood levels
Alligators are common
. RIPARIAN WETLANDS
. predominance of woody plants
shade the water, stabilize the bank, and produce
this directly supports aquatic species plus those
that live on them
. corridors for dispersal and migration
Ecology and Food Webs in Wetlands
(The introductory material on general ecology and
food webs is mostly from:
Caduto, M.J. 1985. Pond and Brook. Hanover,
N.H.: University Press of New England. 276p.)