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Background

Summary 

This page describes in a brief way why genetic biodiversity should be a concern in conservation and management.

Note: For more detailed information to understand what is genetic biodiversity and how it can be assessed go to Assessing conservation status of populations


1. Introduction

2. Why be concerned about genetic biodiversity

3. Who should be concerned about genetic biodiversity

4. When should one be concerned about genetic biodiversity


 

1. Introduction

Genetic biodiversity (genetic differences among individuals of populations, and among populations of a species) is at the base of all biodiversity on earth. It is also the material for evolutionary changes to occur. As with species, genetically different populations have different traits and characteristics that improve their adaptation to live in their ecological niche. In principle there is no more than a gradual difference between being two genetically distinct populations of a species, or being two different species (besides the fact that the latter can exchange genes with each other while the former cannot - resulting in two different species usually being a more dissimilar than two populations of the same species). 

There are actually many examples of when it is not possible to clearly define if two entities are different species or different populations of the same species. The bluemussel in the Baltic Sea is one such example sometimes referred to as one species, Mytilus edulis, but else claimed to be two species, M. edulis and M. trossulus. It is also common in nature that species hybridize (as do the two entities of blue mussels.)

 

2. Why be concerned about genetic biodiversity?

  • Genetic biodiversity is included in the Rio Convention on biodiversity and there is a global political consensus and a responsibility to protect all biodiversity on earth
     
  • Genetic biodiversity contributes to ecosystem function much in the same way as species biodiversity, not least when considering species of key functions in the ecosystem such as top predators, habitat-forming species, main primary and secondary producers, and main microbial species.
     
  • Genetic biodiversity is the insurance towards future evolutionary changes. Species that essentially lack genetic variation (highly inbred species, or species that have been through severe population bottlenecks) do not have as good chances as other species to adapt to environmental changes.
     
  • Genetic biodiversity is what makes local adaptation of populations possible. If not locally adapted populations are protected from extinction, species will be locally lost with potentially devastating effects on the local ecosystem.

Local populations (stocks) of cod have gone extinct from coastal areas along the Swedish west coast. Although juvenile cods from the North Sea stock dispers to these areas each year, rebuilding of the local stocks has not occurred. This is likely a consequence of local adaptation of cods and a consequence of not taking into account genetic biodiversity during management.

 

3. Who should be particularly concerned about genetic biodiversity?

  • Industry that uses or interacts with natural live resources.In the Baltic Sea this means fishing industry, tourism industry and shipping industry.
     
  • Authorities that managed natural live resources.In the Baltic Sea this means environmental projection agencies, fisheries managers and boards and regional and local authorities with responsibilities for coastal zone planning.
     
  • Policy makers and politicians that decides about the legal instruments and policies to be used by industry and authorities in management.

 

4. When should one be concerned about genetic biodiversity?

  • When earlier common populations have decreased considerably in size.
    In the Baltic Sea the local populations of harbour porpoise is today at risk of loss of genetic variation.
     
  • When local populations are at risk of local extinction.
    Local populations of many marine species in the Baltic and in the Skagerrack is at risk of local extinction (in addition to those that have already been extinct).
     
  • When a large part of a population is harvested non-randomly with respect to a trait.
    Selective fisheries, harvesting the large individuals only, has the backside that if growth rate is an inherited trait, this also selects for lower grow and lower fish production.
     
  • When individuals of populations are transplanted (intentionally or unintentionally) into new areas with native individuals of the same species but of another genetic population.
    Transplanting individuals to remote areas will in most cases mean that one risk to introduce harmful gene variants into existing native populations.

 

 

CONTRIBUTOR (January 2012)
Kerstin Johannesson, University of Gothenburg, Sweden


Responsible editor: Kerstin Johannesson, University of Gothenburg, Sweden 
You are welcome to contribute to the development of this section. Please add a comment or visit the Forum. 


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