1.1.1 Global Distribution of Aquatic Macrophytes
Aquatic macrophytes have a world-wide distribution, almost all the biogeographic
regions of the world comprise of greater diversity of these plants. The habitats of
aquatic macrophyte exhibit the most diversified, productive and conglomerate portions of water bodies. To a common man, aquatic macrophytes are those which are of
substantial size to see with a naked eye. This diversified autotroph includes Green
algae (division Chlorophyta), Yellow-green algae (division Xanthophyta) and Blue
green algae (Cyanobacteria). Non vascular plants of Bryophytes (Hornworts and
Musci) and Vascular plants belonging to Pteridophytes as well as Angiosperms.
Among various groups of plants mentioned above, vascular macrophytes were
recorded as early as the mid1800s by Darwin (1859). Further, Aquatic Macrophytes
of Angiosperm group., comprises of 250,000–400,000 angiosperm species, of which
only 2443 species are Aquatic. Ecologically, they are classified as emergent macrophytes (plants with roots and most part of stem submersed in soil and leaves
extending into the air e.g. Typha sps.), submerged macrophytes (plants growing
completely submerged under the water and roots in close association with substrate
e.g. Hydrilla sps.), Rooted floating leaved (plants rooted with the substratum at the
bottom with long petiole and large leaf lamina floats on the facet of water
e.g. Nymphaea sps.) and free-floating macrophytes (plants mostly small sized that
usually float on the water surface e.g. Lemna and Wolffia spp). Representative genera
of Aquatic macrophytes found globally are Sagittaria, Alisma, Butomus, Brasenia,
Cabomba, Callitriche, Ceratophyllum, Scirpus, Carex, Myriophyllum, Elodea,
Vallisneria, Juncus, Lemna, Utricularia, Nelumbo, Nymphaea, Nuphar, Spartina,
Eichhornia, Potamogeton, Ranunculus, Sparganium, and Typha.
Chambers et al. (2008) had studied Global diversity of aquatic macrophytes in
freshwater at a global scale in which they recorded highest species diversity
(984 sps.) of vascular aquatic macrophytes in Neotropics of which 188 species
belonged to the family Podostemaceae which contributed largely towards the diversity of the macrophytes in this region. The study also envisaged that the diversity
was intermediate in the Orient (664 sps), Nearctic (644 sps) and Afrotropic
(614 sps), lower in Palearctic 497 sps and Australasia (439 sps) which still subsides
in the region of Pacific and Oceanic islands (108 sps.). Very few vascular macrophytes were confined to the Antarctica bioregion and that to only in the
sub-Antarctic freshwaters.
The largest and solely found aquatic family of angiosperms in terms of number of
species and genera was Podostemceae. In the Tropics, the plants of this family are
generally found in fast flowing waters. Moreover, in terms of species richness,
Cyperaceae and Poaceae were distributed all over the world except Antarctica. In
contrast to fresh waters, where Aquatic macrophytes show worldwide distribution,
there are only few marine submerged Angiosperms that are found growing in
Coastal areas in shallow waters throughout the world. Among these Zostera and
Phyllospadixbelong to the family Zosteraceae are commonly found Aquatic
macrophytes.
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P. Parikh and K. Unadkat
Aquatic macrophytes have a world-wide distribution, almost all the biogeographic
regions of the world comprise of greater diversity of these plants. The habitats of
aquatic macrophyte exhibit the most diversified, productive and conglomerate portions of water bodies. To a common man, aquatic macrophytes are those which are of
substantial size to see with a naked eye. This diversified autotroph includes Green
algae (division Chlorophyta), Yellow-green algae (division Xanthophyta) and Blue
green algae (Cyanobacteria). Non vascular plants of Bryophytes (Hornworts and
Musci) and Vascular plants belonging to Pteridophytes as well as Angiosperms.
Among various groups of plants mentioned above, vascular macrophytes were
recorded as early as the mid1800s by Darwin (1859). Further, Aquatic Macrophytes
of Angiosperm group., comprises of 250,000–400,000 angiosperm species, of which
only 2443 species are Aquatic. Ecologically, they are classified as emergent macrophytes (plants with roots and most part of stem submersed in soil and leaves
extending into the air e.g. Typha sps.), submerged macrophytes (plants growing
completely submerged under the water and roots in close association with substrate
e.g. Hydrilla sps.), Rooted floating leaved (plants rooted with the substratum at the
bottom with long petiole and large leaf lamina floats on the facet of water
e.g. Nymphaea sps.) and free-floating macrophytes (plants mostly small sized that
usually float on the water surface e.g. Lemna and Wolffia spp). Representative genera
of Aquatic macrophytes found globally are Sagittaria, Alisma, Butomus, Brasenia,
Cabomba, Callitriche, Ceratophyllum, Scirpus, Carex, Myriophyllum, Elodea,
Vallisneria, Juncus, Lemna, Utricularia, Nelumbo, Nymphaea, Nuphar, Spartina,
Eichhornia, Potamogeton, Ranunculus, Sparganium, and Typha.
Chambers et al. (2008) had studied Global diversity of aquatic macrophytes in
freshwater at a global scale in which they recorded highest species diversity
(984 sps.) of vascular aquatic macrophytes in Neotropics of which 188 species
belonged to the family Podostemaceae which contributed largely towards the diversity of the macrophytes in this region. The study also envisaged that the diversity
was intermediate in the Orient (664 sps), Nearctic (644 sps) and Afrotropic
(614 sps), lower in Palearctic 497 sps and Australasia (439 sps) which still subsides
in the region of Pacific and Oceanic islands (108 sps.). Very few vascular macrophytes were confined to the Antarctica bioregion and that to only in the
sub-Antarctic freshwaters.
The largest and solely found aquatic family of angiosperms in terms of number of
species and genera was Podostemceae. In the Tropics, the plants of this family are
generally found in fast flowing waters. Moreover, in terms of species richness,
Cyperaceae and Poaceae were distributed all over the world except Antarctica. In
contrast to fresh waters, where Aquatic macrophytes show worldwide distribution,
there are only few marine submerged Angiosperms that are found growing in
Coastal areas in shallow waters throughout the world. Among these Zostera and
Phyllospadixbelong to the family Zosteraceae are commonly found Aquatic
macrophytes.
310
P. Parikh and K. Unadkat