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== Biodiversity changes ==
 
== Biodiversity changes ==
 
   
 
   
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===Biodiversity importance===
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The most fundamental meaning of [[biodiversity]] is probably the concept of species richness, i.e., the number of species which occur at a given site, or within a region or an [[ecosystem]]. It's often assumed that ecosystems with a higher [[species diversity|diversity]] can better cope with environmental fluctuations. A large number of [[species]] present might increase the [[resilience]] of an ecosystem to changes in environmental conditions or to [[anthropogenic]] impacts.<ref name="ma">[http://www.marbef.org/documents/glossybook/MarBEFbooklet.pdf Heip, C., Hummel, H., van Avesaath, P., Appeltans, W., Arvanitidis, C., Aspden, R., Austen, M., Boero, F., Bouma, TJ., Boxshall, G., Buchholz, F., Crowe, T., Delaney, A., Deprez, T., Emblow, C., Feral, JP., Gasol, JM., Gooday, A., Harder, J., Ianora, A., Kraberg, A., Mackenzie, B., Ojaveer, H., Paterson, D., Rumohr, H., Schiedek, D., Sokolowski, A., Somerfield, P., Sousa Pinto, I., Vincx, M., Węsławski, JM., Nash, R. (2009). Marine Biodiversity and Ecosystem Functioning. Printbase, Dublin, Ireland ISSN 2009-2539]</ref>
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<P>
 +
More information on the importance of biodiversity can be found [[Why_is_Marine_biodiversity_important|here]].
 +
<BR>
 +
<P>
 +
===Biodiversity at risk===
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The [[Valuation and assessment of biodiversity|maintenance of high diversity]] is often seen as something positive to aim for; and to “halt the loss of biodiversity” has [[Conservation_policy_and_legislation|become a major political aim]]. It is now clear that marine ecosystems are at risk, especially those which receive the most pressure from human activities, mainly [[estuaries]], [[intertidal]] shores and [[coastal area|coastal waters]].
  
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The most fundamental meaning of [[biodiversity]] is probably the concept of species richness, i.e., the number of species which occur at a given site, or within a region or an [[ecosystem]]. Higher [[species diversity|diversity]] has often been seen as an advantage for an ecosystem to better cope with
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The composition of species within marine communities can change in three main ways:
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environmental fluctuations (insurance
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* species may be lost ([[Species extinction|extinctions]]);  
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hypothesis). A large species pool might increase
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* species may be added ([[Non-native_species_invasions|invasions]] or [[Evolution#Speciation|speciation]]);  
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the resilience of an ecosystem to changes in
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* species’ relative abundances can change (rare species become abundant, abundant species become rare).<ref name="ma">[http://www.marbef.org/documents/glossybook/MarBEFbooklet.pdf Heip, C., Hummel, H., van Avesaath, P., Appeltans, W., Arvanitidis, C., Aspden, R., Austen, M., Boero, F., Bouma, TJ., Boxshall, G., Buchholz, F., Crowe, T., Delaney, A., Deprez, T., Emblow, C., Feral, JP., Gasol, JM., Gooday, A., Harder, J., Ianora, A., Kraberg, A., Mackenzie, B., Ojaveer, H., Paterson, D., Rumohr, H., Schiedek, D., Sokolowski, A., Somerfield, P., Sousa Pinto, I., Vincx, M., Węsławski, JM., Nash, R. (2009). Marine Biodiversity and Ecosystem Functioning. Printbase, Dublin, Ireland ISSN 2009-2539]</ref>
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environmental conditions or to anthropogenic
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<P>
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impacts.
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An overview of all threats towards marine biodiversity can be found [[Threats_to_Marine_Biodiversity|here]].
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The value of biodiversity as an
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<BR>
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indication of environment health and for
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<P>
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the functioning of ecosystems has been
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===Rare species===
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recognised not only by scientists but
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also by decision-makers and
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Although the number of rare species comprise the majority of the [[taxon|taxa]] in a biologically diverse region, they only form a minority of the biomass. However, when species are removed or added to a community, the energy flow, [[MarBEF_examples_of_fishery_effects#Predator-prey_interactions|predator-prey interactions]] or [[food web]]-related processes may change dramatically. As a consequence, the [[Biological_productivity|productivity]] of the seas is directly affected.<ref name="ma">[http://www.marbef.org/documents/glossybook/MarBEFbooklet.pdf Heip, C., Hummel, H., van Avesaath, P., Appeltans, W., Arvanitidis, C., Aspden, R., Austen, M., Boero, F., Bouma, TJ., Boxshall, G., Buchholz, F., Crowe, T., Delaney, A., Deprez, T., Emblow, C., Feral, JP., Gasol, JM., Gooday, A., Harder, J., Ianora, A., Kraberg, A., Mackenzie, B., Ojaveer, H., Paterson, D., Rumohr, H., Schiedek, D., Sokolowski, A., Somerfield, P., Sousa Pinto, I., Vincx, M., Węsławski, JM., Nash, R. (2009). Marine Biodiversity and Ecosystem Functioning. Printbase, Dublin, Ireland ISSN 2009-2539]</ref>
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the general public.
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<P>
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The maintenance of high diversity is often seen
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<BR>
−
as something positive to aim for; and to “halt
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<P>
−
the loss of biodiversity” has become a major
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== Habitat loss==
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political aim. It is now clear that marine
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ecosystems are at risk, especially those
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[[Marine_habitats_and_ecosystems|Habitat heterogeneity]] is another important factor when describing biodiversity. Presently, a gradual transition from very complex to simpler
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receiving the most sustained and unrelenting
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[[habitats]] is being observed. [http://www.marbef.org MarBEF] explored the numerous [[Habitat_destruction_and_fragmentation#Habitat_loss_and_biodiversity|ways in which habitat loss can affect marine species diversity]], and thus community structure.
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pressure from human activities, such as
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estuaries, intertidal shores and coastal waters.
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The loss of habitat structure is generally thought to lead to lower abundance (biomass) of [[keystone species|key species]] and often to a decline in species richness. However, [[Disturbances%2C_biodiversity_changes_and_ecosystem_stability|experiments in different coastal areas of Europe]], have shown that the removal of key species does not always affect the stability of the ecosystem and that effects depend on where, when and what species are removed. For example, an invading species may replace a resident species which plays an ecologically important role for ecosystem structure and [[Ecosystem_functioning|functioning]]. The ecosystem may continue to function and provide similar services, but not necessarily in the same way as before.<ref name="ma">[http://www.marbef.org/documents/glossybook/MarBEFbooklet.pdf Heip, C., Hummel, H., van Avesaath, P., Appeltans, W., Arvanitidis, C., Aspden, R., Austen, M., Boero, F., Bouma, TJ., Boxshall, G., Buchholz, F., Crowe, T., Delaney, A., Deprez, T., Emblow, C., Feral, JP., Gasol, JM., Gooday, A., Harder, J., Ianora, A., Kraberg, A., Mackenzie, B., Ojaveer, H., Paterson, D., Rumohr, H., Schiedek, D., Sokolowski, A., Somerfield, P., Sousa Pinto, I., Vincx, M., Węsławski, JM., Nash, R. (2009). Marine Biodiversity and Ecosystem Functioning. Printbase, Dublin, Ireland ISSN 2009-2539]</ref>
−
The composition of species within marine
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<BR>
−
communities can change in three main ways:
+
<P>
−
• species may be lost (extinctions); • species may be added (invasions or
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===Biodiversity increases===
−
speciation); • species’ relative abundances can change
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MarBEF also showed that, despite increasing [[Effects_of_fisheries_on_European_marine_biodiversity|pressure from overfishing]], [[Habitat_destruction_and_fragmentation|habitat destruction]] and [[pollution]], species richness appears to be increasing in many coastal and marine European waters. This is due to the establishment of [[Non-native species invasions|non-indigenous species]], especially of warm-water affinity, and to a [[Effects_of_climate_change_on_the_North_Sea_and_Baltic_Sea#Warming_leads_to_an_increase_in_North_Sea_fish_species|general northward movement]] of species due to climate change. The observed increase might also be due to the [[New_species|addition of newly recorded species]] to already existing [[species lists]] which haven’t been amended for a long time, or be related to more intensive research and the discovery and description of rare species.<ref name="ma">[http://www.marbef.org/documents/glossybook/MarBEFbooklet.pdf Heip, C., Hummel, H., van Avesaath, P., Appeltans, W., Arvanitidis, C., Aspden, R., Austen, M., Boero, F., Bouma, TJ., Boxshall, G., Buchholz, F., Crowe, T., Delaney, A., Deprez, T., Emblow, C., Feral, JP., Gasol, JM., Gooday, A., Harder, J., Ianora, A., Kraberg, A., Mackenzie, B., Ojaveer, H., Paterson, D., Rumohr, H., Schiedek, D., Sokolowski, A., Somerfield, P., Sousa Pinto, I., Vincx, M., Węsławski, JM., Nash, R. (2009). Marine Biodiversity and Ecosystem Functioning. Printbase, Dublin, Ireland ISSN 2009-2539]</ref>
−
(rare species become abundant, abundant
+
<P>
−
species become rare).
+
<BR>
−
Although the number of rare species comprise
+
<P>
−
the majority of the taxa in a biologically diverse
+
 
−
region, they do not play a quantitatively
+
== MarBEF research ==
−
important role in the structuring of the
+
 
−
community. However, when species are
+
[[Anthropogenic]] activities such as [[Maritime_Traffic|shipping]] and [[Living_resources#Mariculture_.E2.80.93_Aquaculture|aquaculture]] further enhance the spread of species, even across geographic or ecological boundaries. Such shifts in species or changes in regional biodiversity will have consequences on the structure and functioning of ecosystems.<ref name="ma">[http://www.marbef.org/documents/glossybook/MarBEFbooklet.pdf Heip, C., Hummel, H., van Avesaath, P., Appeltans, W., Arvanitidis, C., Aspden, R., Austen, M., Boero, F., Bouma, TJ., Boxshall, G., Buchholz, F., Crowe, T., Delaney, A., Deprez, T., Emblow, C., Feral, JP., Gasol, JM., Gooday, A., Harder, J., Ianora, A., Kraberg, A., Mackenzie, B., Ojaveer, H., Paterson, D., Rumohr, H., Schiedek, D., Sokolowski, A., Somerfield, P., Sousa Pinto, I., Vincx, M., Węsławski, JM., Nash, R. (2009). Marine Biodiversity and Ecosystem Functioning. Printbase, Dublin, Ireland ISSN 2009-2539]</ref>
−
removed or added to a community, and thus
+
 
−
the biodiversity changes, the energy flow,
+
This raises two questions: Can we expect the same response from all European marine ecosystems? And can we predict how this will affect ecosystem functioning? Below,
−
predator-prey interactions or food web-related
+
some examples are provided of how biodiversity might change in 4 different regions.
−
processes may change dramatically. As a
+
 
−
consequence, the productivity of the seas is
+
*[[Predicted biodiversity changes in the Arctic]]
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directly affected.
+
*[[Predicted biodiversity changes in the Baltic Sea]]
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Structurally complex habitats are
+
*[[Predicted biodiversity changes in the Mediterranean Sea]]
−
becoming rarer across European marine
+
*[[Previous biodiversity changes in the North Sea]]
−
environments.
+
<P>
−
Habitat heterogeneity is another important
+
<BR>
−
factor when describing biodiversity. Presently, a
+
<P>
−
gradual transition from very complex to simpler
+
===See also===
−
habitats has been observed. MarBEF explored
+
 
−
the numerous ways in which habitat loss can
+
[[Thresholds of environmental sustainablility]]
−
affect marine species diversity, and thus
+
<P>
−
community structure, and some examples are
+
<BR>
−
presented in this booklet. The loss of habitat
+
<P>
−
structure is generally thought to lead to lower
+
==References==
−
abundance (biomass) of key species and often
+
<references/>
−
to a decline in species richness.
+
 
−
However, experiments in different coastal areas
+
[[Category:Marine Biodiversity‏‎]]
−
of Europe, performed within MarBEF, have
+
[[Category: MarBEF Booklet]]
−
shown that the removal of key species does not
 
−
always affect the stability of the ecosystem and
 
−
that effects depend on where, when and what
 
−
species are removed. For example, an invading
 
−
species may replace a resident species which
 
−
plays an ecologically important role for
 
−
ecosystem structure and functioning. The
 
−
ecosystem may continue to function and
 
−
provide similar services, but not necessarily in
 
−
the same way as before.
 
−
MarBEF also showed that, despite increasing
 
−
pressure from overfishing, habitat destruction
 
−
and pollution, species richness appears to be
 
−
on the increase in many coastal and marine
 
−
European waters. This is due to the
 
−
establishment of non-indigenous species,
 
−
especially of warm-water 56 affinity, and to a
 

Revision as of 11:23, 6 August 2019

Biodiversity changes

Biodiversity importance

The most fundamental meaning of biodiversity is probably the concept of species richness, i.e., the number of species which occur at a given site, or within a region or an ecosystem. It's often assumed that ecosystems with a higher diversity can better cope with environmental fluctuations. A large number of species present might increase the resilience of an ecosystem to changes in environmental conditions or to anthropogenic impacts.[1]

More information on the importance of biodiversity can be found here.

Biodiversity at risk

The maintenance of high diversity is often seen as something positive to aim for; and to “halt the loss of biodiversity” has become a major political aim. It is now clear that marine ecosystems are at risk, especially those which receive the most pressure from human activities, mainly estuaries, intertidal shores and coastal waters.

The composition of species within marine communities can change in three main ways:

  • species may be lost (extinctions);
  • species may be added (invasions or speciation);
  • species’ relative abundances can change (rare species become abundant, abundant species become rare).[1]

An overview of all threats towards marine biodiversity can be found here.

Rare species

Although the number of rare species comprise the majority of the taxa in a biologically diverse region, they only form a minority of the biomass. However, when species are removed or added to a community, the energy flow, predator-prey interactions or food web-related processes may change dramatically. As a consequence, the productivity of the seas is directly affected.[1]


Habitat loss

Habitat heterogeneity is another important factor when describing biodiversity. Presently, a gradual transition from very complex to simpler habitats is being observed. MarBEF explored the numerous ways in which habitat loss can affect marine species diversity, and thus community structure.

The loss of habitat structure is generally thought to lead to lower abundance (biomass) of key species and often to a decline in species richness. However, experiments in different coastal areas of Europe, have shown that the removal of key species does not always affect the stability of the ecosystem and that effects depend on where, when and what species are removed. For example, an invading species may replace a resident species which plays an ecologically important role for ecosystem structure and functioning. The ecosystem may continue to function and provide similar services, but not necessarily in the same way as before.[1]

Biodiversity increases

MarBEF also showed that, despite increasing pressure from overfishing, habitat destruction and pollution, species richness appears to be increasing in many coastal and marine European waters. This is due to the establishment of non-indigenous species, especially of warm-water affinity, and to a general northward movement of species due to climate change. The observed increase might also be due to the addition of newly recorded species to already existing species lists which haven’t been amended for a long time, or be related to more intensive research and the discovery and description of rare species.[1]


MarBEF research

Anthropogenic activities such as shipping and aquaculture further enhance the spread of species, even across geographic or ecological boundaries. Such shifts in species or changes in regional biodiversity will have consequences on the structure and functioning of ecosystems.[1]

This raises two questions: Can we expect the same response from all European marine ecosystems? And can we predict how this will affect ecosystem functioning? Below, some examples are provided of how biodiversity might change in 4 different regions.


See also

Thresholds of environmental sustainablility


References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Heip, C., Hummel, H., van Avesaath, P., Appeltans, W., Arvanitidis, C., Aspden, R., Austen, M., Boero, F., Bouma, TJ., Boxshall, G., Buchholz, F., Crowe, T., Delaney, A., Deprez, T., Emblow, C., Feral, JP., Gasol, JM., Gooday, A., Harder, J., Ianora, A., Kraberg, A., Mackenzie, B., Ojaveer, H., Paterson, D., Rumohr, H., Schiedek, D., Sokolowski, A., Somerfield, P., Sousa Pinto, I., Vincx, M., Węsławski, JM., Nash, R. (2009). Marine Biodiversity and Ecosystem Functioning. Printbase, Dublin, Ireland ISSN 2009-2539
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