Talk:Overexploitation/Archive 1

=Description= I purpose modifying the description of overexploitation to "Overexploitation is an ecological term to describe one of the five main activities threatening global biodiversity. It is also extensively used in fisheries. Essentially, it means populations are harvested at a rate that is unsustainable, given their natural rates of mortality and capacities for reproduction.  This can result in harvesting ‘to the point of diminishing returns’ and extinction at the population level and even extinction of whole species."

Any objections or additions?


 * Matt, I suspect you may be doing a little OR here. Your definition of overexploitation, as occurring when "populations are harvested at a rate that is unsustainable", seems to be equating overexploitation with unsustainablity. If that is the case, then we don't need this article when we already have one on sustainability. However, your definition does not mesh, at all, with the way the term is used in fisheries. In fisheries, as I have already spelt out in detail in the article, overexploitation can be perfectly compatible with sustainability. Indeed, the FAO had a recent international conference specifically looking at overexploitation and unsustainablity as contrasting concepts (cited in the reference section). The term is used more in fisheries than in other contexts, as you can easily check from Google. Also you haven't sourced the key statement you placed in the lead, that overexploitation is "a term used in ecology, as one of the five main activities threatening global biodiversity". For example, has this been explicitly stated by the Millennium Ecosystem Assessment? Are are you sure they use the term "overexploitation"? Unless you can clearly establish that, in ecology and conservation biology, the term is used in a definitive and unambiguous way, and that the term is in fact a key term within those disciplines, then I do not think it is a good idea to demote the fisheries context to an afterthought. --Epipelagic (talk) 22:26, 1 February 2010 (UTC)


 * No, I am not doing original research. There are 13 references on this now. That's 5 more than on fisheries you added. If you read the journals or the books, it clearly states what i've written. I am an Ecologist, I was taught about overexploitation of many species, not just fishes. I also gave you additional material on my talk page. Here are easy to click links just from googleing '5 causes of extinction, overexploitation' there were 101,000 results.


 * http://en.wikipedia.org/wiki/State_of_the_planet#2._.22Why_Is_There_a_Crisis.3F.22
 * http://en.wikipedia.org/wiki/Extinction#Causes
 * http://www.enviroliteracy.org/article.php/1514.html
 * http://darwin.eeb.uconn.edu/eeb310/lecture-notes/extinctions/node3.html


 * I understand why you might think overexploitation and sustainability are related. As stated in the article, the phenomenon of sustainability came from overexploitation, as did many other concepts. Sustainability is one of many solutions to overexploitation. In the same way water can be a solution to fire, but they are not the same. Sustainability is a conservation effort, overexploitation is an ecological observation.


 * I am not trying to demote or detract away from fisheries, there is extensive material there in Overfishing etc, and links to these articles on the page. Matt (talk) 00:10, 2 February 2010 (UTC)


 * Somehow Matt, you are ignoring the issues I raised. Overexploitation became a significant issue in the late 20th century because wild fisheries were collapsing. The concept was developed in relation to wild marine life. The overexploitation of wild terrestrial animals was literally a dead issue before ecology and conservation biology were born. Since then, the use of the term has been expanded to include things like the overexploitation of forests and water resources, so there are definitely ways in which ecologists use the term away from fisheries..


 * You say that, for ecologists, overexploited population = unsustainable population. If you are right, then for ecologists, overexploited = unsustainable, and they don't need a separate concept for overexploited. Also, and somewhat seriously, according to you, ecologists are using the term in a way that is incompatible with the way the term is used by the FAO and in fisheries. Bear in mind that many FAO advisor and fisheries scientists are also ecologists.


 * The issue has nothing to do with how many sources you cite, it is a question of the credibility and relevance of the sources. Can you find, for example, a widely accepted textbook on ecology or conservational biology with a chapter titled "Overexploitation", which sets out the concept of overexploitation the way you are describing it. Or can you find ecology papers writen for top journals, like Nature and Science, that use the term the way you are defining it? Can you find any FAO reports that use the term the same way? Reports from the Millennium Ecosystem Assessment would be good, since that is a definitive collective effort by many of the world's most prominent ecologists.


 * And to repeat, you also make the uncited assertion in the lead, that overexploitation is "a term used in ecology, as one of the five main activities threatening global biodiversity". That is a heavyweight assertion which needs to be supported with heavyweight sources. --Epipelagic (talk) 01:55, 2 February 2010 (UTC)


 * OK Epipelagic, maybe you have not read my talk page? (http://en.wikipedia.org/wiki/User_talk:Matt-eee#Overexploitation). It addresses your issues on overexploitation.


 * You state “Can you find, for example, a widely accepted textbook on ecology or conservational biology with a chapter titled "Overexploitation", which sets out the concept of overexploitation the way you are describing it”. Maybe I was not clear enough, so here is your answer:


 * Book Title: Essentials of Conservation Biology (3rd ed.). Author: Richard B. Primack. Sinauer Associates, Inc Publishers. Page 265, Chapter 10 Title: Overexploitation. Indeed, my very definition of overexploitation came from an Ecology text book, which is referenced in the article.  It comes from Page 474 under the section Overexploitation.  This section does not mention fisheries; it does not mention sustainability


 * “The issue has nothing to do with how many sources you cite, it is a question of the credibility and relevance of the sources“


 * I also gave you articles published in two scientific journals “Conservation Biology” and “Biodiversity and Conservation”. These are qualitative!


 * You state: “according to you, ecologists are using the term in a way that is incompatible with the way the term is used by the FAO and in fisheries”


 * By 'you' I assume you mean 'Townsend, C.R. Begon, M. and Harper, J.L. (2003). Essentials of Ecology, 2nd edition. Page 474. Blackwell Publishing. Oxford.' as this is where the definition comes from and cited. In addition, I have not said this is incompatible with fisheries.  Overexploitation is overexploitation no matter what the species.  There is a vast amount of data on fisheries and overfishing and I am not detracting away from this and I find it strange that you have deleted the links from the article, in favour of your brief synopsis? Please explain this.  BTW overexploitation threatens one-third of endangered vertebrates, as well as other groups. EXCLUDING EDIBLE FISH, the illegal trade in wildlife is valued at $10 billion per year. Try looking at the ‘bushmeat crisis’, for example, or the trade in Chinese medicine, or the fur trade.


 * You state: “the term [overexploitation] has been expanded to include things like the overexploitation of forests and water resources.


 * Ecology deals with living organisms and the relationships between organisms. In the strictest of terms an ecologists would not deal with overexploitation of water resources, unless in the context of its affect on species other than humans.  When talking about sustainability we factor in a human element because it is usually an economic activity that is the cause and needs addressing.  This is when overexploitation deviates from an ecological perspective.  An ecologist, for example, would not be overly interested in the depletion of oil reserves, but would be interested in the effects of burning that oil has on ecosystems.


 * You state “overexploited population = unsustainable population. If you are right, then for ecologists, overexploited = unsustainable and they don't need a separate concept for overexploited”


 * OK. You talk about unsustainable as if it were sustainability. This is a fallacy, in much the same way correct is not the same as incorrect, stable is not the same as unstable.  If overexploited = unsustainable, where is the unsustainable page on wiki?  There isn’t one. Plus unsustainable is not a definitive term, although it is used, overexploitation is.  Looking in back of the two books I have mentioned, I can see in the index page: “overexploitation” and “sustainability” and “sustainable development”.  If we want to merge this article with another, the very least we need an ecological definition of the term.


 * You state: “The concept was developed in relation to wild marine life. The overexploitation of wild terrestrial animals was literally a dead issue before ecology and conservation biology were born”.


 * Point one:
 * the term Ecology was first used in 1866, it is an extension of natural history which extends back to much earlier. For example, the concept on the balance or regulation of nature can be traced back to Herodotos (died c. 425 BC) who described an early account of mutualism along the Nile river where crocodiles open their mouths to beneficially allow sandpipers safe access to pluck leaches away. This is Ecology


 * Conservation Biology is a much later discipline. Roots of conservation biology can be found in the late 19th century particularly in England and Scotland. The concept took off in America, for example, with the loss of Bison, Wolves, Passenger Pigeon to name a few. All of this long before the 1920’s and the decline of fishing industries.


 * Point two
 * But we can go further back than that. Ceremonial clocks worn by the Hawaiian kings were made from the mamo bird (Drepanis sp.); a single clock used the feathers of 70,000 birds of this now-extinct species. Further back still, the dodo, became extinct because of overexploitation. Further back still, the New Zealand Moa, extinct, reason = overexploitation. In fact in modern terms there are two waves of extinctions, in what is known as a blitzkrieg, or overkill hypothesis.  That when early humans arrive at a new location extinction occurs.  This is known as the Holocene extinctions.  The second wave is from European colonisation. Jared Diamond has written many books and papers on this.


 * So, 1. the concepts of Ecology and Conservation are not old and certainly around before the 1920’s. And 2. Overexploitation has been observed for 100’s of years, long before the first detailed look at the over harvesting of fisheries, which, BTW, was done by Russell, E.S. 1931. "Some theoretical considerations on the 'overfishing' problem". Journal du Conseil Permanente International poul l/Exploartion de la Mar 6:3-27. However, I do agree that since the overfishing crisis a vast amount of research was developed specifically for fishing. I noted this on my talk page.


 * Finally


 * You state: “you also make the uncited assertion in the lead, that overexploitation is "a term used in ecology, as one of the five main activities threatening global biodiversity"


 * This is a well known fact in Ecology. Main focus tends to be on the individual factors as authors are looking in detail at one or maybe two specific causes.  But I have already given numerous sources. Try this one: Wilcove, D.S., Rothstein, D., Dubow, J. Phillips, A. and Losos, E. (1998). Quantifying Threats to Imperilled Species in the United States. BioScience. 48, 607-615.


 * Matt (talk) 12:04, 2 February 2010 (UTC)


 * another important note is that in Ecology, overexploitation is not limited to human activities Matt (talk) 12:30, 2 February 2010 (UTC)


 * Okay. So we need to find a way to clarify how the term is used in different ways in different disciplines. I suppose conservation biology is more focused on threats to biodiversity, and the notion of sustainable exploitation is of little interest. In fisheries, by contrast, populations are by definition exploited. Sustainable exploitation is important, particularly exploiting in a way that maximizes the yield. Fish species are not usually at risk of extinction through overexploitation in the way terrestrial species often are, because marine environments are often much more resilient.


 * I deleted the links to sustainability and overfishing which you placed at the top of the page, not "in favour of [my] brief synopsis", but because the links are already in the "See also" section towards the bottom of the page. Links at the top of the page are usually disambiguation links, which is not needed here.


 * Overexploitation is not just a term used in ecology and conservation biology. It is used in many other contexts, more than I initially thought actually, and in the next two sections below I have pointed to some of these. We need to find a way of accommodating these different uses. I agree a statement along the lines of "Overexploitation is an ecological term to describe one of the five main activities threatening global biodiversity" should be prominent in the article. It is an important statement, and it needs proper sourcing (along with how best to characterise the other four activities). But the article should not be written in a way that implies that it is only ecologists and conservation biologists who have a claim to the term. --Epipelagic (talk) 02:00, 3 February 2010 (UTC)


 * ok. i understand where you going this. good work. i've added as mush as i can today. we're now on 20,605 bytes. its a bit rushed but I don't have any more time at the mo to invest. if by fivefold it means five times, then we're on the money! -Matt (talk) 16:41, 3 February 2010 (UTC)


 * References

Usage
Here are some web definitions of overexploitation
 * exploitation to the point of diminishing returns (seems to be the most widely used definition on the web)
 * excessive and damaging exploitation
 * unsustainable use of a natural resource leading to the depletion or degradation of the resource and consequent loss of its availability or ...
 * excessive consumption of a renewable natural resource at a rate that cannot be maintained due to a dwindling reproductive population
 * use of / harvesting of an environmental resource at a rate which exceeds the natural growth / regeneration rate. ...

The following table gives a Google perceptive on how the term is used in different contexts. The basic search expression used here is: "overexploitation OR over-exploitation":

Following is the definition of overexploitation used by CITES, together with some interesting comments from a working group. They are arguing over some of the same issues we are discussing.

10. OVER-EXPLOITATION (Doug Butterworth)

A population is in a state of biological over-exploitation when its abundance has been reduced below the level which, on average, provides the greatest net rate of productivity (in absolute, as distinct from per capita terms);

A population is being biologically over-exploited when both its abundance is below the level which, on average, provides the greatest net rate of productivity, and the rate of harvest exceeds the rate which is, on average, sustainable for the population's current level of abundance.

One needs the "biological" to distinguish from the different concept of "economic over-exploitation", and the "on average" to cover for natural variability (though what I've suggested isn't water-tight, as strictly one would need to distinguish short-term variations from longer-term/"regime-shift" changes (i.e. some linkage to generation time in regard to the period over which the average is taken). I've expressed what are essentially maximum sustainable yield and sustainable yield as rates to avoid having to state a time unit. The parenthetical piece re "absolute" and "per capita" is to avoid the frequent confusion of production by the population as a whole with production on a per-individual basis. Instead of "sustainable" (which begs another definition), one might like to stick with the current Appendix II equivalent of "can be continued in perpetuity". Some might prefer "abundance" or "size"?
 * Note

While these definitions are interesting, and quite good, we do not believe that over-exploitation needs to be defined, or that defining it here will assist the CITES Parties. A preferable definition would be (however): over-exploitation occurs when harvest decreases population growth to below replacement; i.e., negative population growth rate that occurs when deaths (natural and from harvest) plus emigration exceeds births plus immigration.
 * Comments from the USA

We do not believe that we should use the term "sustainable" here, or attempt to define it in the criteria.

These definitions argue for maximum sustainable yield (MSY) considerations, which I do not believe we should be the basis for the CITES listing criteria. The concept is certainly valid in some contexts, but we do not believe that the Parties should utilize the concept in the listing criteria. We would be glad to discuss this further at the meeting of the Criteria Working Group. --Epipelagic (talk) 00:08, 3 February 2010 (UTC)

Overexploitation, economics and diminishing returns
I'm coming at this from a perspective of an economist, which is perhaps not ideal, but I do have some problem with the lede definition of Overexploitation as "refers to harvesting a renewable resource to the point of diminishing returns" - diminishing returns has a pretty precise meaning in economics and basically it means "requires more and more of an input to get (extract) a given level of output (harvest)". But this kind of thing characterizes a very wide range of production processes and diminishing returns kick in pretty quickly. Basically, diminishing returns can arise way before a level that, as far as I understand it from this article, is considered overexploited or unsustainable.

Reading the article I think the confusion is between "diminishing returns" and "optimal yield", as characterized in this sentence from the article, from the part on the fisheries, "in this case, the fishery is sustainable, but is now overexploited, because the stock has been run down to the point where the sustainable yield is less than it could be". In fact for there to BE a maximum sustainable yield, diminishing returns must have already set in.

So it's three different concepts, as far as I can see:
 * diminishing returns - it takes more and more of an input to get a unit of output (you can have diminishing returns, but neither overexploitation or unsustainability)
 * overexploitation - having run down the stock to the point where the yield is less than it could be, but the population is not going to collapse (like a lower, bad, "steady state" - but a steady state nonetheless)
 * unsustainability - having run down the stock and harvesting at a rate which ensures the population will collapse.

Basically I think diminishing returns are necessary but not sufficient condition for the other two. Ok, that's a bit of OR there - but it's only meant to illustrate that the opening definition of the lede is itself OR.

Good article btw.radek (talk) 03:54, 10 February 2010 (UTC)

Rewrote sentence
Hi I just deleted and rewrote this sentence "If sustained, it can lead to the destruction of the resource" because 1. its passive and 2. sustained can be confused with "sustainable resource" and that is the opposite of what the article is discussing..." —Preceding unsigned comment added by 66.41.159.79 (talk) 05:12, 20 November 2010 (UTC)


 * You replaced "If sustained, [overexploitation] can lead to the destruction of the resource" with "Continued over time, overexploitation eventually destroys the resource". Your replacement is not appropriate, as you will see if you actually read the article (particularly the bit about overexploited but sustainable fisheries). --Epipelagic (talk) 07:15, 20 November 2010 (UTC)

reptiles?
How come no discussion of overharvesting of reptiles? They are very sensitive to it, especially some of the turtle species, because of their slow maturation and long-lived nature. Many classic cases of overharvesting in the past (and present).TCO (talk) 05:49, 12 March 2011 (UTC)
 * Yep, reptiles and turtles could be mentioned in the section on endangered species, along with some other missing groups, like sharks, whales and elephants. And perhaps a mention that species which grow slowly and mature late have low resilience (such as orange roughy), and are easy to overharvest. --Epipelagic (talk) 07:19, 12 March 2011 (UTC)
 * Fancy meeting you here.TCO (talk) 18:47, 12 March 2011 (UTC)

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