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The mission of the International Association of Bryologists (IAB), as a society, is to strengthen bryology by encouraging interactions among all persons interested in byophytes.

Friday, October 9, 2009

BRYONET: local endemics


Hello everyone,

I tried to keep out this time, but obviously I cannot stop my fingers. I
especially believe that, as pointed out by Brent, the application of the
species concept in other biological disciplines is an important issue to
consider in this context. With this in mind, I wonder if the present
species discussion could possibly profit from being broken down into two
portions. (1) What do we know about how it looks? (2) How can we put
names on it in a way that promotes rather than hampers a deeper

(1) The first question concerns the patterns of both phylogenetic
(historical) relationships and functions that we find among organisms in
nature. The patterns of phylogenetic relationships describe how
organisms are related to each other by descent, including complications
caused by various kinds of processes that we know exist; among these
gradual lineage divergence, hybridization, and speciation causing
paraphyly have been mentioned. I have the impression that few biologists
today question that such patterns do exist. I believe that the patterns
of phylogenetic relationships also describe some important aspects of
biodiversity in the most accurate way. With our present knowledge on how
organisms are related to each other, the knowledge of these aspects of
biodiversity cannot be substituted by any of the traditional species
concepts in a satisfying way. This is crucial to consider in our efforts
for more efficient biodiversity conservation.

Turning to the functional patterns among organisms, these describe how
members or groups of members of various lineages interact with each
other and the surrounding non-living environment. I have difficulties
imagining that exactly one or some of the traditional species concepts
should pinpoint the exact level of interest in such a functional
context. There are certainly good reasons why the population level is
considered most suitable in some functional contexts, whereas various
kinds of groups of 'traditional species' (genera, orders, guilds, etc.)
are considered, rather than the individual 'species' in other cases. The
'traditional species' can probably (?) be used as approximations of
certain aspects of organism function and interaction, but to believe
that we can reach an understanding of many (most?) aspects of how
biological life functions if we restrict ourselves to studying exactly
these seems to me a bit optimistic.

(2) The second question concerns the terminology suitable to describe
these patterns. It is evident that neither the phylogenetic
relationships nor all the functional patterns are well reflected or
described by traditional species concepts and that the latter are
therefore likely to hamper our understanding of both biodiversity and
various processes in nature. To my mind, the discussion of 'species
concepts' or perhaps better another terminology (to avoid the species
issue; see Paul Wilson's mail) would therefore profit from first
discussing the patterns that we now begin to understand exist. If we
agree which such patterns do exist we then need to ask how these are
best reflected in a new (?) terminology, in a way that promotes our
understanding of nature rather than the opposite? Please note that I
agree with Paul Wilson that there may still be contexts where
'traditional species' are suitable entities, for example in teaching and
approximations across large geographical ar
eas when no more detailed information is presently available. However,
our current lack of knowledge of how most of life is organised should
not be allowed to stop us from further exploration that may reveal new
insights. If the present species terminology stops us, or some of us, to
ask the right questions this is a good argument for striving for a
better terminology.

If we disagree on my admittedly rough description of different kinds of
existing organism relationships, we still need to discuss this issue
before we can begin to explore a suitable terminology to best describe them.

Best wishes, Lars

Lars Hedenäs
Swedish Museum of Natural History
Department of Cryptogamic Botany
Box 50007
SE-104 05 Stockholm
ph: +46-(0)8-51954214

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