[Coral-List] Biodiversity extinction

Mon Feb 1 17:23:44 EST 2010

Comes to mind the story of the complete overfishing of cod on the Grand Banks. Atlantic cod is absolutely not extinct. The cod fisheries are extinct (with much social hardship). The ecosystem has been so changed that cod stocks haven't even recovered in marine reserves where all fishing has been prohibited for decades. For centuries cod catch was sustainable at about 500,000,000 kg per year. That is serious money. The pain is not only to the ecosystem, but clearly also economic.

The issue is not only species going extinct or biodiversity loss. The real question is how we humans organize our lives and economic activities so that we don't plunder nature, destabilize ecosystems, wipe out species and destroy opportunities for our own offspring. Biodiversity loss is but one aspect and fortunately, we're at least discovering some species before we bring them to extinction. Unfortunately, we cannot know how many we have never known...

Best wishes, GJ

--
Gert Jan Gast
Koningin Wilhelminakade 227, 1975GL IJmuiden, the Netherlands
Ph +316 5424 0126, Fax +31255 521546, Skype gjgast

From: Katie Peterson [mailto:kpeter8 at tigers.lsu.edu]
Sent: maandag 1 februari 2010 20:23
To: GJ
Cc: R.D.; coral-list at coral.aoml.noaa.gov
Subject: Re: [Coral-List] Biodiversity extinction

RD,

I would also like to add that biodiversity loss is greater than just a quantitative loss of species.  It affects the ecological interactions within a community.  This can change what species occupy certain niches, which could have negative trophic effects.  Everyone on this mailing list should be familiar with the keystone predator concept, and the ramifications of the loss of that species or something indirectly connected to it.  Robert Paine's classic "Food Web Complexity and Species Diversity" (1966) ring a bell?  Once the delicate balance is shifted, natural selection could favor for increased biodiversity as you mentioned, or it could create a situation where an organism has the opportunity to thrive without competition or predation, wiping out other organisms in the food web, killing the community (analogous to an invasive species).  So, although "new" species are being identified and catalogued, they cannot always replace the the ecological role of certain species or the intrinsic value of biodiversity.

Katie Peterson
Senior, Marine Biology & Coastal Environmental Science
Louisiana State University

On Mon, Feb 1, 2010 at 8:24 AM, GJ <GJ at fishion.eu<mailto:GJ at fishion.eu>> wrote:
RD,

Firstly,for your information, it is common practice on this list that one shows his/her name in either email address or message.

Your confusion lies in the difference between new species being discovered and new species evolving. Most species discovered were already there and often for millions of years. Although they are presented as new to raise attention, they are not exactly a "new" to our planet.
The answer to your question lies in time scales.
The forming of new species of animals or plants through evolution usually occurs on the scale of hundreds, thousands or even million years. Also, evolution is not a continuous process but often goes in spurts (sort of a river going down rapids).
The loss of species we humans are causing is happening on the scale of decades.
Certainly we're losing more than new ones can be created through evolution.

Biodiversity loss is not the same as species loss. If a tropical rainforest is replaced by a meadow of grass, it is still green. But the biodiversity is much much lower. The biggest problem with coral reefs is that those 700-800 species of hard coral build the structure of the reef in which all the thousands and thousands of other creatures find a place to live. Destruction of that physical structure causes immense biodiversity loss as you can easily see on the many eroded sand flats with coral rubble that were thriving coral reef communities just a few decades ago. The scientific evidence is everywhere in scientific journals, NGO output, films, etc.

Certainly killing all the ants will cause biodiversity loss in your neighborhood. Whether resistant ants evolve depends if you keep poisoning. If you do it once adaptation through evolution cannot happen. If circumstances return to the situation before the poisoning you will probably first see other species occupy the empty space, but with time that the same species dominate the ecosystem. But I don't think you need to do this experiment. There are sufficient unintended examples all over the planet of altered ecosystems as the result of human chemical waste disposal.

Good luck, GJ

--
Dr Gert Jan Gast - Fishion Consultancy
Koningin Wilhelminakade 227, 1975GL IJmuiden, the Netherlands
Ph +316 5424 0126, Fax +31255 521546, Skype gjgast
----- Original Message -----
From: "R.D." <scubadivingdoc at yahoo.com<mailto:scubadivingdoc at yahoo.com>>
To: <Coral-List at coral.aoml.noaa.gov<mailto:Coral-List at coral.aoml.noaa.gov>>
Sent: Friday, January 29, 2010 8:57 AM
Subject: [Coral-List] Biodiversity extinction

> As a non-academic with field experience in coral conservation, coral
> disease, and marine park science and politics, I would like to comment on
> the recent Biodiversity extinction post, keeping in mind the "big
> picture".
>
> In the past few years several scientific biodiversity expeditions have
> reported in the lay press the discovery of thousands of new marine species
> from the Phillipines to Antartica to Australia to Tasmania to New Guinea
> and on and on. Such species have been scientifically collected, catalogued
> and classified. A Google search for "new marine species" yields a treasure
> trove of articles.
> On the other hand, an internet search for recently extinct marine
> species(especially credited to human influence) reveals sparse data.
> Therefore, when a scientist speaks about "stopping the loss of
> biodiversity" and "continued biodiversity extinction" it seems incongruous
> to the reported facts. Is there scientific data to confirm this loss?
> Which species have been lost and how many? When we talk about habitat
> destruction, anthropogenic global warming, and overfishing, is there
> scientific data to confirm a "loss of biodiversity"? Or is it an
> assumption that it has happened or will happen?
> It is my understanding that environmental stressors rarely destroy an
> entire species(except for mass extinction events). In fact it is often
> environmental changes that allow new mutations to take hold and encourages
> the development of new species. As an example, a 2007 scientific survey of
> the Celebes Sea turned up between 50 and 100 new species of fish and
> invertebrates in an area that has been isolated by rising sea levels.
> So my question is,"Is isolated habitat destruction on coral reefs really
> contributing to loss of biodiversity?" Is there scientific evidence?
> Or is the following analogy appropriate - If my entire neighborhood
> poisons all of the ant hills in our back yards, are we contributing to the
> loss of biodiversity? Will poison-resistant ants develop? Will different
> species of ants move in? Will the same species relocate from other areas?
> I hate to see human induced damage to coral reefs as much as anyone. But
> loss of coral cover does not equal extinction of species.
> And if you are going to try to convince the general public otherwise, you
> will need to show them what species we have lost and how they have helped
> cause that loss. Because as of now, for every marine species put on the
> endangered list, there are hundreds or thousands newly discovered.
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