Subject: Re: Future vegetation change in Uk by Global Warming. Any idea?
From: <[email-masked]>
Date: Wed, 11 May 1994 21:45:39 EST
Newsgroups: bionet.plants

Kei,

     There are several possibilities. With global warming one may see a
shift in weather patterns. As a result, the nice warm blast of air
and water which the British Isles currently get may change coarse. The
result would actually result in a cooling in your area. I am not a
global climate modeler, so I cannot tell you the likelyhood of this
event or the severity of the change.
    As an ecosystem ecologist I can tell you that a few degrees in
temperature change would shift the current plant populations further
north and would probobly result in the extinction of some of your
endemic species because it would be difficult for the populations
to migrate north do to the patchiness of habitat caused by man's
influences (roads, dams, cities, farms, etc.). Some would be lost
wether or not these barriers existed but more will be lost. The
result of the population shift may create new communities as fast
migrating population move through slower migrating populations.
Of course some old communities will be lost as well.
    Now, to answer the suggestion that striga or other tropical
parasitic plants may move into the area. It is highly unlikely that
striga would migrate in to the UK. There are too many barriers. It
currently is an african species and would require migration accross
the mediteranean,over the pyrenes, and accross france. It seems that
this would be an unlikely occurance. It may happen that it would be
unwittingly introduced as happened in North Carolina (USA). But I
don't expect that the temperature rise will be significant enough to
allow plants that would survive the winters.
   Other possibilities include resonses to CO2 rise regardless of
temperature rise. Higher levels of CO2 increase production and some
studies have shown an increase in water use efficiecy. However other
studies have shown sclerosis and a study I am doing now shows a change
in rooting patterns with depth and turnover. To be honest the jury is
still out on the effects of CO2. We know that the effects happen, we
just aren't too sure what those effects are.
   Finnally, with global warming, one expects to there to be less
precipitation. As a result, wet areas may become more mesic and dry
areas become bone dry. More deserts, less arable land. Combined with
the temperature change, there may be a need to shift agricultural
priorities from say lettuce to soy beans or some other less water
hungry plant.
   Well there you have it. My two cents. Good luck, there should be
several sources on community change. and I know there are many on
responses to CO2. Hugo Rogers just published a paper on the belowground
resonses of plants to increased CO2.

                       Best of luck,
                           Everett Weber
                           Dept. of Biology
                           Old Dominion University
                           Norfolk VA USA