17
Species diversity in saltmarshes is not very high because the flora must be tolerant of harsh environments such as extremes in salinity, submersion, and anoxic sediment conditions. Marsh plant communities are well known for zonation based on
the tidal level. The dominant species, which include glassworts and cordgrass
(Pennings and Bertness 2001) or reeds (Chap. 8; Otani and Endo 2018), are determined by biogeographical constraints and the characteristics of the abiotic environment such as salinity and tidal levels.
1.3.2 Mangrove Forests on Tidal Flats in Subtropical
and Tropical Regions
Mangrove forests also form unique coastal plant communities. They are found at the
interface of land and sea, a habitat that encompasses elements of both terrestrial and
marine environments. Mangrove forests are therefore sometimes characterized as
terrestrial forests, despite the fact that mangrove trees grow in saline or brackish
water in tropical and subtropical regions. Mangrove forests and saltmarshes become
established under similar environmental conditions, but the former are found at subtropical and tropical latitudes and the latter in temperate and subarctic latitudes
(Fig. 1.3b). The areal extent of mangrove forests has been thoroughly studied and is
estimated to be about 1.52 × 10
7
ha globally (Chap. 3; Inoue 2018).
Mangrove forests consist of salt-tolerant mangrove trees that have complex saltfiltration systems as well as complex root systems to survive saltwater immersion
and the anoxic conditions of the sediments. Red mangroves (Rhizophora spp.) can
Fig. 1.3a Global map of saltmarsh distribution (bold-lined areas). Created with reference to
UNEP-WCMC (2017a)
1 Blue Carbon: Characteristics of the Ocean’s Sequestration and Storage Ability…
Species diversity in saltmarshes is not very high because the flora must be tolerant of harsh environments such as extremes in salinity, submersion, and anoxic sediment conditions. Marsh plant communities are well known for zonation based on
the tidal level. The dominant species, which include glassworts and cordgrass
(Pennings and Bertness 2001) or reeds (Chap. 8; Otani and Endo 2018), are determined by biogeographical constraints and the characteristics of the abiotic environment such as salinity and tidal levels.
1.3.2 Mangrove Forests on Tidal Flats in Subtropical
and Tropical Regions
Mangrove forests also form unique coastal plant communities. They are found at the
interface of land and sea, a habitat that encompasses elements of both terrestrial and
marine environments. Mangrove forests are therefore sometimes characterized as
terrestrial forests, despite the fact that mangrove trees grow in saline or brackish
water in tropical and subtropical regions. Mangrove forests and saltmarshes become
established under similar environmental conditions, but the former are found at subtropical and tropical latitudes and the latter in temperate and subarctic latitudes
(Fig. 1.3b). The areal extent of mangrove forests has been thoroughly studied and is
estimated to be about 1.52 × 10
7
ha globally (Chap. 3; Inoue 2018).
Mangrove forests consist of salt-tolerant mangrove trees that have complex saltfiltration systems as well as complex root systems to survive saltwater immersion
and the anoxic conditions of the sediments. Red mangroves (Rhizophora spp.) can
Fig. 1.3a Global map of saltmarsh distribution (bold-lined areas). Created with reference to
UNEP-WCMC (2017a)
1 Blue Carbon: Characteristics of the Ocean’s Sequestration and Storage Ability…