This thread contains statements of the kind that I think get us in
trouble, if not with the public, then with our scientific rigor. Axel
Ringe's post begins with what looks like an inclusion from a previous post
with this statement "...one metaphor for biodiversity that I remember was
the phrase "web of life". The imagery contained in that phrase not only
conveys the complexity (species richness)of the organisms making up an
ecosystem, but can also convey the importance of the connections and
dependencies among those organisms. Pluck one strand, and the whole web may
collapse..."
Sure, it's presented as a metaphor, but is it a good one? First of
all, I have never seen a spider web collapse because on strand was plucked.
Spiders are better engineers than that. Even if you *sever* a thread, it
usually only causes part of the web to fold up on itself. Second, does
anyone know of an ecosystem that has collapsed because one species (or some
other entity) was "plucked"? Also, what does it mean to say that an
ecosystem has collapsed? That all it's species are extinct? That the
habitat that it once occupied is now barren and lifeless? Extreme
overfishing may cause an extinction or two, and we can say that the fishery
has collapsed, but that collapse is an economic phenomenon, not ecological.
The chestnut plague in the early twentieth century virtually wiped
out the American chestnut, a dominant species of the eastern forest canopy
in many places. This caused hardship for humans who used chestnut products,
but I'm not aware of any other species that died off with it. In fact, we
could say that many other tree species benefited as they moved into gaps
left by the chestnut. Slaughtering the American bison was, in my opinion, a
terrible crime, but the vultures loved it, at least for a while.
If we want a vivid metaphor to promote conservation and that will
stick in the public's mind, maybe we should talk about "environmental
rape." This makes the point and at also makes clear that we are talking
about *human values*, not scientific truths.
Now to Warren Aney's quote: "...A single-age, single-species tree
plantation may be productive in economic
terms but it lacks species, genetic and structural diversity so it is not as
ecologically productive, stable or resilient as it could be because of this
lack of biodiversity...."
Yes, of course it lacks species, genetic, and structural diversity,
because that's how it was defined. This is like saying an all-wood house
lacks bricks. It's true, but then what? Further, since it is a plantation,
it's not supposed to be "ecologically productive." It's supposed to produce
whatever its owner's planted it for, presumably wood. Nor is it supposed to
be stable or resilient; it's supposed to last for thirty years or so and
then be harvested. Admittedly, during this time its low diversity might
make it vulnerable to disease outbreaks, but this risk may be economically
justified by the ease of managing a uniform stand and then clearcutting it.
Why am I kvetching about these points? In the context of a list
serve, I think it is fine to throw out ideas and see what people make of
them. However, if these issues are not well thought out and carefully
articulated before they are advanced as the basis for public policy, they
will not hold up well in debate. The proponents may wind up looking bad and
their cause harmed rather than helped.
Martin M. Meiss
2010/12/16 Warren W. Aney <[email protected]>
> As a field ecologist who has frequently evaluated and described natural
> systems in their entirety and then communicated this information to
> non-scientists, I find the term and concept of biodiversity very helpful.
> To me, the best definition is the most general definition: biodiversity
> relates to diversity of species (including genetic and age diversity) and
> of
> structure, currently and over time. A system with high biodiversity tends
> to be more productive, stable and resilient.
>
> A single-age, single-species tree plantation may be productive in economic
> terms but it lacks species, genetic and structural diversity so it is not
> as
> ecologically productive, stable or resilient as it could be because of this
> lack of biodiversity.
>
> Warren W. Aney
> Senior Wildlife Ecologist
> 9403 SW 74th Ave
> Tigard, OR 97223
> (503) 539-1009
> (503) 246-2605 fax
>
> -----Original Message-----
> From: Ecological Society of America: grants, jobs, news
> [mailto:[email protected]] On Behalf Of Alexandre F. Souza
> Sent: Thursday, 16 December, 2010 13:37
> To: [email protected]
> Subject: [ECOLOG-L] Defining Biodiversity
>
> Hi Euan,
>
> I use the broad definition of biodiversity as senctioned by the US
> Congressional Biodiversity Act, HR1268 (1990), according to which
>
> "biological diversity means the full range of variety and variability
> within and among living organisms and the ecological complexes in which
> they occur, and encompasses ecosystem or community diversity, species
> diversity, and genetic diversity."
>
> I think biodiversity should continue to have a broad and
> all-encompassing meaning, and the communication problem you mention
> arises much more from the use of the term in place of more specific
> ones, when we refer to specific issues. When communicating with the
> public, we should be more specific when speaking about specific issues,
> rather than abolishing a term that has a broad meaning, and that should
> be reserved for broad themes.
>
> The California Biodiversity Council has a compilation of scientific
> definitions of biodiverstiy
> (http://biodiversity.ca.gov/Biodiversity/biodiv_def2.html).
>
> Best whishes,
>
> Alexandre
>
> Date: Mon, 13 Dec 2010 15:05:31 -0800
> From: "Ritchie, Euan" <[email protected]>
> Subject: Defining biodiversity, and does the term capture the public's
> attention?
>
> Hi everyone,
>
> I have just returned from the Ecological Society of Australia meeting
> and a=
> mong other issues, there was much discussion about the term
> biodiversity. M=
> any people argue that this term is hard to define, and importantly, the
> pub=
> lic have no idea what it actually means and therefore they have less
> connec=
> tion/concern to preserve/conserve species and habitats. I thought it
> would =
> be interesting to hear how others define biodiversity, and if this term
> isn=
> 't helpful for conveying the importance of species diversity to the
> public,=
> what term(s) should we use?
>
> Over to you,
>
> Euan
>
>
> Dr. Euan G. Ritchie, Lecturer in Ecology, School of Life and
> Environmental =
> Sciences
>
>
> Dr. Alexandre F. Souza
> Programa de Pós-Graduação em Biologia: Diversidade e Manejo da Vida
> Silvestre
> Universidade do Vale do Rio dos Sinos (UNISINOS)
> Av. UNISINOS 950 - C.P. 275, São Leopoldo 93022-000, RS - Brasil
> Telefone: (051)3590-8477 ramal 1263
> Skype: alexfadigas
> [email protected]
> http://www.unisinos.br/laboratorios/lecopop
>
