Sunday, November 14, 2004

The Circle of Life

The quality of the environment of Earth is going to get much worse.  Therefore, it is good to remind ourselves, from time to time, of the tremendous costs that this will entail.  Although the study reported here may not seem like a major study, it serves as a reminder that everything on the planet is linked together.  It may be inconvenient to acknowledge that fact, and it will cost money to act on it, but we cannot afford to ignore it. 

Declining Fish Supply Linked to Land Animal Extinctions
Scientific American
November 12, 2004

An analysis of nearly 30 years of data on African wildlife has uncovered a link between declining fish stocks and increased hunting and bushmeat trade. The results suggest that when fish sources of protein wane, people turn toward illegal hunting on land, which can lead to species extinction.

Justin S. Brashares of the University of California at Berkeley and his colleagues studied animal census information collected between 1970 and 1998 by park rangers in Ghana and compared it to information collected about the fish supply in the region over the same time period. The researchers found a 76 percent drop in overall abundance for the 41 species studied, which included buffalo, antelope, jackal and lion. In particular, the team discovered that in years with a below average fish supply, there was a greater decline in the land animal populations. In addition, some smaller game reserves experienced local extinctions of nearly half the studied species.

The team also studied the sale of bushmeat in 12 rural markets throughout Ghana in 1999 and found that poor fishing seasons were inversely related to both the price of fish and the amount of bushmeat available for sale. “Our study present very strong evidence showing how human food supply can be directly related to conservation of wildlife,” Brashares says. “We need people working together across disciplines to look at how losses of marine resources are impacting land resources and vice versa.” --Sarah Graham
The extinction of a species may not seem like a big deal, if you think of plants and animals as replaceable raw material.  But that is only one aspect of the problem.  The loss of a species also means a loss of one component of the ecosystem, which can be expected to have a negative impact on everything else.  It also represents the loss of irreplaceable genetic material. 

Ardent proponents of industry are prone to dismiss such things are irrelevant.  They look at a study of something obscure, do not see why it is important, and assume that it must not be important.  The next study illustrates this nicely.  Scientists studied the top layer of mud at the bottom of the ocean.  That certainly is obscure, and admittedly, it is not obvious right that it is important...

Extinction in ocean's mud presages key ecological changes
Science Blog
Posted on Friday, November 12, 2004 @ 5:00 PM PST by bjs

The loss of seemingly inconsequential animal species in the marine benthos - the top 6 inches or so of mud and sediment on the floors of the world's oceans - is giving scientists a new look ahead at the consequences of the steady decline of the world's biological diversity.

In new work published today in the journal Science, an international team of scientists describe work in which the ocean mud and the many animals that live there are used to forecast how the extinction of species alters important ecological processes that sustain life at the bottom of the ocean. [...]

And while the creatures that inhabit the mud at the bottom of the ocean may seem remote and unimportant, Cardinale pointed out that oceans cover 70 percent of the Earth's surface, and that the productivity of the sea is intricately linked to sediments that generate nutrients and food for other organisms such as fish. In places where human activities have disrupted marine sediments, such as the enormous ''dead zone'' in the Gulf of Mexico - where excess fertilizers are dumped by the Mississippi River - nearly all life has vanished.  [...]

When a species becomes extinct, there is another loss.  We loose -- forever -- the scientific knowledge that would have come from the study of that species, and from the study of how that species interacted with other components of the ecosystem.  Again, it may not be obvious, to some, just how big of a loss this is.  Remember: scientific knowledge has to be understood in a broad context to be meaningful.  Anytime you loose part of the context, that which remains has lost some of its value.