The necessity of the rearing of non-commercial aquatic species in Austria, and prerequisites for the similar situation in Russia
The general dramatic decline of biodiversity is progressing even faster in aquatic habitats. Highly specialized species living in a narrow ecological niche are on the edge of extinction or have already died out. But not only species with a complex life-cycle that often depend on host species, or animals and plants that need a pristine environment are at risk. In Austria and other European countries, even species that used to be common and abundant until recently have turned out to be endangered or even on the edge of extinction when subject of thorough investigation. This development has sped up in the past few decades because of various reasons. In most cases, there is not just a single reason for the decline, it is rather the combination of habitat loss, climate change and intensified utilization of the catchment areas that leads to combined effects that often actually intensify each other. In Austria the decline of freshwater mussels, all native crayfish species, lampreys and several small fish species is so dramatic that artificial rearing is required to prevent their extinction. In Russia such measures are not realized yet in most cases, though similar processes of environmental degradation and intensification of land use are taking place. The awareness of the latter has led to the knowledge that certain prominent and well-surveyed species like the freshwater pearl mussel do need serious conservation measures regardless of their still large numbers. The bigger part of the endangered species, however, still remain unexplored in the context of conservation biology. This paper presents a review of recent studies in this field. Refs 26.
population decline, species extinction, conservation, non-commercial species
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