Major threats
to these ecosystems are; land reclamation for food production as well as infrastructure
construction, water abstraction for irrigation and industrial as well as domestic uses, disconnection
from parent rivers, overuse of resources, eutrophication and pollution and invasive species. These
threats will include increases in temperatures, changes in the total amount and distribution pattern
of precipitation, and sealevel rise. The dominant drivers of change affecting aquatic ecosystems
include rise in water temperature and hydrological changes, followed by an increase in the nutrient
loading and salinization. In some cases temperature increase will
end up with an extinction of
characteristic species. The biotic communities in standing waters will cause an increase in the
frequency of stratification periods, productivity and algal blooms together with eutrophication. Other
factors include invasions of exotic species and the exploitation of aquatic biota such as harvest of
fish, crustaceans and other organisms, as well as fibres from the reeds. Freshwaters mainly in Asia
are increasingly used for aquaculture, effected by eutrophication, pollution, escape of cultured
organisms to the wild and spread of diseases as
well as local habitat changes, acidification,
salinization, organic pollution, genetic disruption and toxic stress (Janse et al., 2015).
Caspian is the largest enclosed brackish inland water system, rich in oil and gas, with salinity up to
13.7 percent, experiencing significant changes in water levels and embodying diversified habitats
from vast river systems to extensive wetland systems. The presence of large shallow areas, pose a
potential threat to biodiversity and especially endemics in the sea. Its biodiversity together with the
coastal zone make it one of the most valuable ecosystems in the world. Biological endemism rate in
the Caspian is extremely high, with a large number of representatives from almost all major phyla on
earth. It abounds in diverse flora and fauna with high natural productivity. Most important
species is
the sturgeon, with a standing stock of 85 percent from the world's sturgeon population. Illegal and
overfishing are dramatically reducing the sturgeon population. The loss of spawning grounds and
nesting sites follows the sea-level changes. Pollution and introduced species are also effective. The
Sea lies on the crossing of migration routes of millions of migrating birds and offers refuge to a
number of rare and endangered birds of the world ornithofauna. The threats like regulation of its
rivers, leading to a loss of reeds, cattail and bushes, as well as aquatic and coastal fauna are needed.
A detailed ecological survey of the coastal and marine species and habitats, their uses, values and
threats, all along the Caspian coastal areas is needed. Some anadromous
and semi-migratory species
have been deprived of their natural spawning grounds. An inventory of its ecological resources must
be prepared in detail to develope the strategies for the management of transboundary biodiversity,
including threatened or endangered migratory species.
The Caspian Sea is a unique ecosytem, but is facing enormous pressure from several
anthropogenic stressors. It is facing a multitude of ecological challenges like; industrial and biological
contamination, sea level fluctuation, fisheries overexploitation, management failure and collapse of
commercial fish stocks, illegal fishing and poaching, invasion of
Mnemiopsis leidyi, eutrophication,
loss
of biodiversity, and environmental mismanagement. Moreover, the Caspian Sea environment
and bio-resources have been - and will be - inevitably exposed to on-going global climatic changes
which is still a largely-ignored issue in the management in this region.
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