water level leads to large, shallow water areas, in which Sphagnum species are
imported from other areas, where they are common. The water should be very
shallow, so that waves cannot destroy the vegetation layer. However, the most
frequent species on these large areas were only four of them: Sphagnum fallax and
S. cuspidatum and the two cotton grasses Eriphorum vaginatum and
E. angustifolium. These are often dominating across hugh areas during the first
years after the beginning of restoration activities.
First experiments to cultivate Sphagnum species, which are more able to establish
hummocks, were reported by Raabe et al. (2018). Under lab conditions the breeding
of Sphagnum spp. was successful. However, the field experiments are not ready, yet.
The cultivated species are rarely found in mires which were peat mined, so that they
have to be selected from remaining vegetation with care.
Beside the active support of restoring characteristic vegetation the elimination of
non-characteristic plants is another important management tool. The drained bogs
are—in case that they are not under agricultural use—invaded by plants, which are
not dominating in natural habitats. These are on the one hand different grasses, in
Northern Europe especially Molinia coerulea, on abandoned grassland also Juncus
effuses and others. On the other hand shrubs and trees are immigrating. Regionally
distributed pioneer trees belong to birch (Betula pubescens), willow, spruce and pine
species. These immigrants are not only competing for light, but also transpirate
much water (up to a few hundred liters per day) and cover the lower vegetation with
leaf fall. Appropriate measures to eliminate those plants, or at least minimize their
impact, are mowing, grazing, cutting of trees and shrubs.
4 Freshwater Habitats: Running and Still Waters
Freshwater habitats can be classified with respect e.g. to geology and age, geography
and elevation, nutrient availability, and others (cf. e.g. Davies et al. 2004; Janssen
et al. 2016).
Figure 3 shows an impressive example of a karst spring in Croatia.
Large rivers belong to the putative oldest terrestrial ecosystems on Earth with an
uninterrupted history as long as the water is flowing. Some of them changed the flow
direction caused by orogenesis millions of years ago. For example, the watershed
migration and changing course of the Amazon river during the last 20 Ma is
described in Albert et al. (2018).
Settlements, cities and industries have preferably been established along rivers
and at the coasts. Freshwater habitats are used e.g. for drinking water, transportation,
elimination of waste, and fishery. Fish normally can be caught during the whole year,
i.e. also during cold and dry seasons and thus, reduces the risk of malnutrition (Klee
1985; Allan 1995).
Lakes in most cases are relatively young and originated during the late Pleistocene or Holocene, and thus are not very species-rich or rich in endemics. In contrary,
a few lakes represent water bodies that exist since a few or many millions of years.
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M. Lindner and C. Hobohm
imported from other areas, where they are common. The water should be very
shallow, so that waves cannot destroy the vegetation layer. However, the most
frequent species on these large areas were only four of them: Sphagnum fallax and
S. cuspidatum and the two cotton grasses Eriphorum vaginatum and
E. angustifolium. These are often dominating across hugh areas during the first
years after the beginning of restoration activities.
First experiments to cultivate Sphagnum species, which are more able to establish
hummocks, were reported by Raabe et al. (2018). Under lab conditions the breeding
of Sphagnum spp. was successful. However, the field experiments are not ready, yet.
The cultivated species are rarely found in mires which were peat mined, so that they
have to be selected from remaining vegetation with care.
Beside the active support of restoring characteristic vegetation the elimination of
non-characteristic plants is another important management tool. The drained bogs
are—in case that they are not under agricultural use—invaded by plants, which are
not dominating in natural habitats. These are on the one hand different grasses, in
Northern Europe especially Molinia coerulea, on abandoned grassland also Juncus
effuses and others. On the other hand shrubs and trees are immigrating. Regionally
distributed pioneer trees belong to birch (Betula pubescens), willow, spruce and pine
species. These immigrants are not only competing for light, but also transpirate
much water (up to a few hundred liters per day) and cover the lower vegetation with
leaf fall. Appropriate measures to eliminate those plants, or at least minimize their
impact, are mowing, grazing, cutting of trees and shrubs.
4 Freshwater Habitats: Running and Still Waters
Freshwater habitats can be classified with respect e.g. to geology and age, geography
and elevation, nutrient availability, and others (cf. e.g. Davies et al. 2004; Janssen
et al. 2016).
Figure 3 shows an impressive example of a karst spring in Croatia.
Large rivers belong to the putative oldest terrestrial ecosystems on Earth with an
uninterrupted history as long as the water is flowing. Some of them changed the flow
direction caused by orogenesis millions of years ago. For example, the watershed
migration and changing course of the Amazon river during the last 20 Ma is
described in Albert et al. (2018).
Settlements, cities and industries have preferably been established along rivers
and at the coasts. Freshwater habitats are used e.g. for drinking water, transportation,
elimination of waste, and fishery. Fish normally can be caught during the whole year,
i.e. also during cold and dry seasons and thus, reduces the risk of malnutrition (Klee
1985; Allan 1995).
Lakes in most cases are relatively young and originated during the late Pleistocene or Holocene, and thus are not very species-rich or rich in endemics. In contrary,
a few lakes represent water bodies that exist since a few or many millions of years.
320
M. Lindner and C. Hobohm