259
D. Kar, Wetlands and Lakes of the World,
DOI 10.1007/978-81-322-1023-8_17, © Springer India 2013
Wetland ecosystem has traditionally been
considered as transitional seres between open
lakes and terrestrial forests. The accumulation of
organic material from plant production was seen to
build up the surface until it was no longer fl ooded
and could support fl ood-tolerant terrestrial forest
species (autogenic succession). An alternative
hypothesis is that the vegetation found at a wetland
site consists of species adapted to the particular
environmental conditions of that site (allogenic
succession). It is believed that both allogenic and
autogenic forces act to change wetland vegetation.
The idea of a regional terrestrial climax seems to
be inappropriate. A number of models have been
suggested for wetland plant developments, which
include the functional guild model, the environmental sieve model, the gap dynamic model and
the centrifugal organisation concept.
Further, wetlands appear to be mature in some
respects and young in others, if one looks at ecosystem attributes as indices of ecosystem maturity.
Indications of young systems generally include
high productivity, export of some amount of production and opening of mineral cycles. On the
other hand, some of the properties of matured systems are accumulation of much structural biomass
in peat, generally high spatial heterogeneity, etc.
17.1 Wetland Plant Development
The initial conditions at the site and the subsequent
events generally characterise the beginning
and subsequent development of a plant community. The general concept of succession is
the replacement of plant species in an orderly
sequence of development. This concept was
clearly enunciated by Clements ( 1916 ) and
applied to wetlands by the English ecologist
W. H. Pearsall in 1920 and by an American
named L. R. Wilson. Later, E. P. Odum ( 1969 )
had adapted and extended the ideas of those
early ecologists to include ecosystem properties, such as productivity, respiration and
diversity. Notwithstanding the above, it is
important to note here that the classical concept of succession had been a dominating paradigm of great importance in plant ecology.
However, at present, it is in disarray. Gleason
( 1917 ) had enunciated an ‘individualistic’
hypothesis in order to explain the distribution
of plant species. His ideas were later developed
into the ‘continuum’ concept (Whittaker 1967 ).
It holds that the distribution of a species is governed by its response to environment (allogenic
succession).
17
Wetland Ecosystem Development
D. Kar, Wetlands and Lakes of the World,
DOI 10.1007/978-81-322-1023-8_17, © Springer India 2013
Wetland ecosystem has traditionally been
considered as transitional seres between open
lakes and terrestrial forests. The accumulation of
organic material from plant production was seen to
build up the surface until it was no longer fl ooded
and could support fl ood-tolerant terrestrial forest
species (autogenic succession). An alternative
hypothesis is that the vegetation found at a wetland
site consists of species adapted to the particular
environmental conditions of that site (allogenic
succession). It is believed that both allogenic and
autogenic forces act to change wetland vegetation.
The idea of a regional terrestrial climax seems to
be inappropriate. A number of models have been
suggested for wetland plant developments, which
include the functional guild model, the environmental sieve model, the gap dynamic model and
the centrifugal organisation concept.
Further, wetlands appear to be mature in some
respects and young in others, if one looks at ecosystem attributes as indices of ecosystem maturity.
Indications of young systems generally include
high productivity, export of some amount of production and opening of mineral cycles. On the
other hand, some of the properties of matured systems are accumulation of much structural biomass
in peat, generally high spatial heterogeneity, etc.
17.1 Wetland Plant Development
The initial conditions at the site and the subsequent
events generally characterise the beginning
and subsequent development of a plant community. The general concept of succession is
the replacement of plant species in an orderly
sequence of development. This concept was
clearly enunciated by Clements ( 1916 ) and
applied to wetlands by the English ecologist
W. H. Pearsall in 1920 and by an American
named L. R. Wilson. Later, E. P. Odum ( 1969 )
had adapted and extended the ideas of those
early ecologists to include ecosystem properties, such as productivity, respiration and
diversity. Notwithstanding the above, it is
important to note here that the classical concept of succession had been a dominating paradigm of great importance in plant ecology.
However, at present, it is in disarray. Gleason
( 1917 ) had enunciated an ‘individualistic’
hypothesis in order to explain the distribution
of plant species. His ideas were later developed
into the ‘continuum’ concept (Whittaker 1967 ).
It holds that the distribution of a species is governed by its response to environment (allogenic
succession).
17
Wetland Ecosystem Development