defining relict plant species

[John grehan]

At 04:33 PM 6/19/2003 +1000, Ms Anolia Lynch wrote:

>While phylogenetic relicts are relatively easy to identify, it is more
>difficult to define which taxa now occur in remnant distributions.  Even
>the related concept of distinguishing between neo-, holo- and
>palaeoendemics is rarely attempted.
>I would welcome any comments in regard to relict species (and refugia),
>and related (preferably more recent) literature, as the relationships
>between species and their degree of environmental adaptation is of
>particular interest to me.

It seems to me that the concept of 'relict' is contextual so there is no
recipe for either (and recent vs older literature would have little to
add). With respect to 'relictual' distributions, there are some interesting
possibilities indicated for plant and animal distributions in the New
Zealand archipelago provided by Heads (1990, New Zealand Journal of
Zoology) in his nested arcs model for biogeographic endemism). For example,
there are examples of restricted distributions on the 'mainland' that may
be traditionally viewed as relicts of a formerly widespread range according
to Darwinian biogeographic criteria that show up instead as having been
originally restricted distribution through the intersection of a horstian
arc. A similar possilbility arises within mainland Australia with the
McPherson-Mcleay overlap.

John Grehan