The typical vegetation of bogs is composed by bryophytes, small Cyperaceae and
dwarf shrubs. The water level is high and a high amount of organic material is stored
in the ground. This material can be accumulated under water if oxygen is absent so
that microorganisms cannot mineralize the litter from plants. Specialized bryophytes
such as Spagnum spp. are able to rise the level of wetlands above groundwater, and
create elevated bogs. These very specialized ecosystems normally relay only on the
input of rainfall. Exceptionally, bogs can occur on mineral soils in regions with
extremely nutrient-poor groundwater. The organic layer is called peat, and peat can
accumulate to vertical dimensions of several meters.
Due to the requirement of nutrient-poor water bogs are limited to areas with high
rainfall or low evaporation (oligotrophic-mesotrophic conditions). In the northern
hemisphere the boreal region, and in coastal areas e.g. of the British Isles bogs are
widespread. In high mountain zones with high precipitation rates and nutrient-poor
soils bogs are common as well.
If the surface of accumulation of organic material is at the level of (mineral)
groundwater, the system is called fen or swamp. Fens occur in different climate
zones and all areas with a high groundwater level, e.g. along rivers, in coastal areas
with high waterlevel (e.g. in the Netherlands) or in basins with limited water runoff.
The nutrient content of the water in the soil is normally a little bit higher than in bogs
(often mesotrophic). In eutrophic environments the characteristic assemblages can
be maintained by regular reduction of above-ground biomass via grazing or moving.
Fens are normally more productive than bogs, and vascular plants such as herbs,
Cyperaceae and Poaceae are dominant.
Swamps often occur in the same areas as mires. Swamps can exist on mineral and
organic soil. Tall grasses, i.e. Cyperaceae and Poaceae, but also members of other
monocot families with a reed-habit are often dominant. Some swamps can be
ephemeral, so they exist only in some season of the year according to the precipitation or to floods in rivervalleys. Soils under swamp can often be characterized as
mesotrophic-eutrophic.
3.1 Current Trends
The distribution and survival of wetland habitats depends on climate and can be
altered due to climate change. It can recently be observed that the precipitation rate in
certain areas increases while other areas are getting more and more dry (e.g. Lindsay
2016). Thus, some wetlands will disappear, others might appear. Due to specific
modes of dispersal this trend might threaten certain characteristic species.
Enforced by the Ramsar convention, but also by several calls from researchers all
over the world, two trends are currently seen: the enforcement of protection and the
restoration of wetlands.
Wetlands: Challenges and Possibilities
315
dwarf shrubs. The water level is high and a high amount of organic material is stored
in the ground. This material can be accumulated under water if oxygen is absent so
that microorganisms cannot mineralize the litter from plants. Specialized bryophytes
such as Spagnum spp. are able to rise the level of wetlands above groundwater, and
create elevated bogs. These very specialized ecosystems normally relay only on the
input of rainfall. Exceptionally, bogs can occur on mineral soils in regions with
extremely nutrient-poor groundwater. The organic layer is called peat, and peat can
accumulate to vertical dimensions of several meters.
Due to the requirement of nutrient-poor water bogs are limited to areas with high
rainfall or low evaporation (oligotrophic-mesotrophic conditions). In the northern
hemisphere the boreal region, and in coastal areas e.g. of the British Isles bogs are
widespread. In high mountain zones with high precipitation rates and nutrient-poor
soils bogs are common as well.
If the surface of accumulation of organic material is at the level of (mineral)
groundwater, the system is called fen or swamp. Fens occur in different climate
zones and all areas with a high groundwater level, e.g. along rivers, in coastal areas
with high waterlevel (e.g. in the Netherlands) or in basins with limited water runoff.
The nutrient content of the water in the soil is normally a little bit higher than in bogs
(often mesotrophic). In eutrophic environments the characteristic assemblages can
be maintained by regular reduction of above-ground biomass via grazing or moving.
Fens are normally more productive than bogs, and vascular plants such as herbs,
Cyperaceae and Poaceae are dominant.
Swamps often occur in the same areas as mires. Swamps can exist on mineral and
organic soil. Tall grasses, i.e. Cyperaceae and Poaceae, but also members of other
monocot families with a reed-habit are often dominant. Some swamps can be
ephemeral, so they exist only in some season of the year according to the precipitation or to floods in rivervalleys. Soils under swamp can often be characterized as
mesotrophic-eutrophic.
3.1 Current Trends
The distribution and survival of wetland habitats depends on climate and can be
altered due to climate change. It can recently be observed that the precipitation rate in
certain areas increases while other areas are getting more and more dry (e.g. Lindsay
2016). Thus, some wetlands will disappear, others might appear. Due to specific
modes of dispersal this trend might threaten certain characteristic species.
Enforced by the Ramsar convention, but also by several calls from researchers all
over the world, two trends are currently seen: the enforcement of protection and the
restoration of wetlands.
Wetlands: Challenges and Possibilities
315