4.2 Freshwater Habitat Restoration
Depending on the kind of anthropogenic pressure to freshwater habitats such as
rivers and lakes current restoration measures are numerous. According to a simple
internet analysis based on the keywords wetland restoration, freshwater habitat
restoration and freshwater species conservation recommended and currently
performed measures can be summarized under the headings: water level, flow
regime, water quality (1), natural structure and zonation, biodiversity (2), natural
functions, ecosystem functions, ecosystem services (3), cause analysis, monitoring,
evaluation/assessment (4), strategy, method, investment, cost efficiency (5), legislation, protection, restriction (6), multi-disciplinarity, communication, education (7).
5 Assessment, Challenges and Possibilities
The five most important threat categories for wetland habitats in declining order are
pollution e.g. with acidic substances, fertilizers, waste, metal, pesticides and medical
device (1), natural system modification, i.e. modification of flow and geomorphology by settlements, establishment of industries, drainings, building of dams, barrages and hydroelectric power stations (2), biological resource use, e.g. fishery and
hunting (3), invasive and other problematic species, genes and diseases (4), and
agriculture and aquaculture (5). However, some of the threat categories are
connected, for example agriculture and pollution (use of pesticides; IUCN 2019,
cf. Scheffer et al. 2001, Leppäkoski et al. 2002). Global maps published online in
FEOW (2019) display distribution patterns e.g. of threatened and endemic freshwater fish, amphibian, turtle and crocodile species (Fig. 4).
Vörösmarty et al. (2010) analysed threat indices and found a strong relationship
between threats to human water security and river biodiversity.
According to the IUCN Red List (2019; cf. Table 1) freshwater lakes, ponds and
rivers harbour the majority of threatened wetland species. Smaller numbers are
related to mires s.l. and subterranean habitats.
Africa and East, South and Southeast Asia are the continental regions with the
most threatened species. Europe represents a little bit more threatened species than S
America or Mesoamerica plus Caribbean Islands.
The majority of endangered species is represented by three groups: fish, amphibian and mollusk species.
Numbers of threatened biota are obviously related to both natural richness on the
one hand and anthropogenic pressure on the other.
The Habitats Directive (92/43/EEC) and the Water Framework Directive of the
European Union (2000/60/EC) implemented the target of a good ecological status
and a good chemical status under minimal anthropogenic impact. However, decades
after the directives entered into force in 1992 and 2000, respectively, many mires and
freshwater habitats across Europe still face serious problems caused by industry and
Wetlands: Challenges and Possibilities
323
Depending on the kind of anthropogenic pressure to freshwater habitats such as
rivers and lakes current restoration measures are numerous. According to a simple
internet analysis based on the keywords wetland restoration, freshwater habitat
restoration and freshwater species conservation recommended and currently
performed measures can be summarized under the headings: water level, flow
regime, water quality (1), natural structure and zonation, biodiversity (2), natural
functions, ecosystem functions, ecosystem services (3), cause analysis, monitoring,
evaluation/assessment (4), strategy, method, investment, cost efficiency (5), legislation, protection, restriction (6), multi-disciplinarity, communication, education (7).
5 Assessment, Challenges and Possibilities
The five most important threat categories for wetland habitats in declining order are
pollution e.g. with acidic substances, fertilizers, waste, metal, pesticides and medical
device (1), natural system modification, i.e. modification of flow and geomorphology by settlements, establishment of industries, drainings, building of dams, barrages and hydroelectric power stations (2), biological resource use, e.g. fishery and
hunting (3), invasive and other problematic species, genes and diseases (4), and
agriculture and aquaculture (5). However, some of the threat categories are
connected, for example agriculture and pollution (use of pesticides; IUCN 2019,
cf. Scheffer et al. 2001, Leppäkoski et al. 2002). Global maps published online in
FEOW (2019) display distribution patterns e.g. of threatened and endemic freshwater fish, amphibian, turtle and crocodile species (Fig. 4).
Vörösmarty et al. (2010) analysed threat indices and found a strong relationship
between threats to human water security and river biodiversity.
According to the IUCN Red List (2019; cf. Table 1) freshwater lakes, ponds and
rivers harbour the majority of threatened wetland species. Smaller numbers are
related to mires s.l. and subterranean habitats.
Africa and East, South and Southeast Asia are the continental regions with the
most threatened species. Europe represents a little bit more threatened species than S
America or Mesoamerica plus Caribbean Islands.
The majority of endangered species is represented by three groups: fish, amphibian and mollusk species.
Numbers of threatened biota are obviously related to both natural richness on the
one hand and anthropogenic pressure on the other.
The Habitats Directive (92/43/EEC) and the Water Framework Directive of the
European Union (2000/60/EC) implemented the target of a good ecological status
and a good chemical status under minimal anthropogenic impact. However, decades
after the directives entered into force in 1992 and 2000, respectively, many mires and
freshwater habitats across Europe still face serious problems caused by industry and
Wetlands: Challenges and Possibilities
323