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Author: V. Loeschcke Publisher: Birkhäuser ISBN: 3034885105 Category : Science Languages : en Pages : 427
Book Description
It follows naturally from the widely accepted Darwinian dictum that failures of populations or of species to adapt and to evolve under changing environments will result in their extinction. Population geneti cists have proclaimed a centerstage role in developing conservation biology theory and applications. However, we must critically reexamine what we know and how we can make rational contributions. We ask: Is genetic variation really important for the persistence of species? Has any species become extinct because it ran out of genetic variation or because of inbreeding depression? Are demographic and environmental stochas ticity by far more important for the fate of a population or species than genetic stochasticity (genetic drift and inbreeding)? Is there more to genetics than being a tool for assessing reproductive units and migration rates? Does conventional wisdom on inbreeding and "magic numbers" or rules of thumb on critical effective population sizes (MVP estimators) reflect any useful guidelines in conservation biology? What messages or guidelines from genetics can we reliably provide to those that work with conservation in practice? Is empirical work on numerous threatened habitats and taxa gathering population genetic information that we can use to test these guidelines? These and other questions were raised in the invitation to a symposium on conservation genetics held in May 1993 in pleasant surroundings at an old manor house in southern Jutland, Denmark.
Author: Joseph G. Cloud Publisher: Springer Science & Business Media ISBN: 9780306445323 Category : Medical Languages : en Pages : 336
Book Description
The problem is that, with the continuing degradation of water and habitat quality, selective harvesting, genetic enhancement programs, and the introduction of hatchery fish into wild populations, the genetic makeup of fish is changing radically. In 27 papers from a workshop held in Moscow, Idaho, an
Author: R.J.F. Smith Publisher: Springer Science & Business Media ISBN: 3642823483 Category : Science Languages : en Pages : 258
Book Description
Fish migration is important and spectacular. Migratory fish gather energy in one portion of the environment and transport it to other areas, where it often becomes available to humans or to other elements in the ecosystem. Migration brings fish into situations that allow easy harvest as they concentrate along migration routes. Their journeys also make them vulnerable to human intereference at critical points along their route. Salmon, for example, may harvest plankton in the open ocean and transport that food energy to coastal and inland regions, where it is captured by fisheries or deposited in inland streams and utilized by the flora and fauna of the region. These salmon are able to complete journeys of thousands of kilometers from their natal streams to oceanic feeding grounds and back to the same home streams, an accomplishment that strains our credi bili ty . We now understand some of the timing and guiding stimuli used in these migrations, and mechanisms can be logically proposed, on the basis of the established abilities of fishes, to account for the unexplained portions of the migrations. There is no single factor guiding these fish. Instead, they are dependent on the presence in their environment of a great variety of appropriate orienting and timing stimuli. These stimuli are vulnerable to human interference. The more widespread and easily available the information on these requirements, the more readily fish can be protected from such interference.