Subject: Carpobrotus edulis

From: Bernard Zwischenbrugger <eras007>
Date: 20 Jun 1995 19:04:00 GMT

THE   DESTRUCTIVE   CAPACITIES   OF    CARPOBROTUS EDULIS

1.Central question:

What factors determine whether Carpobrotus edulis overgrows, surrounds
or grows around other plant-species ?

2.The research for this project was done in march, 1995 in Amoreira,
Portugal. At this moment I'm writing my project-report. To do this I
analyzed the data we collected in Portugal. I also found articles about
C. edulis in California and Guernsy. The articles describe the situation
in California in 1991, and Guernsy in 1988. I would like to know:

-How is C.edulis is doing now in California and Guernsy ?
-Are there other places where C.edulis has been introduced, and
 how does the plant grows there ?

       Can someone give remarks or additions to the comparing of the
       different sites I made ?

3.comparing of the different sites:
-----------------------------------------------
CALIFORNIA

(Carla M. D'Antonio and Bruce E. Mahall, American Journal of Botany
78(7):885-894, 1991, Root profiles and competition between the invasive
exotic perennial, Carpobrotus edulis and two native shrub species in
California coastal shrub)

Santa Barbara County

  climate:
Mediterranean climate, modified by coastal fog.
Rainfall occurs between October and April and averages 38 cm per year.

  soil:
Flat terrace within 300 m. of the ocean, at opproximately 30 m. above sea
level. The soil consists of Eolian sands from the Oceano formation overlying
a clay and iron-containing hardpan between 90 and 150 cm below the soil
surface

  introduction:
Exact date is not known, but aerial photographs suggest that the species was
common in the area by the mid 1960s

  other plant-species at site:
Haplopappus ericoides and H. venetus

  problems caused bij C. edulis:
C. edulis surrounds and grows over many native plant species in California
coastal communities

  remarks:
You mailed me that in California a lot of C.edulis died because of the severe
frost in the winter of 1990-1991. Now there's a lot of "Livingston Daisy"
growing. Did all Carpobrotus in California die ? Are there any signs that
Carpobrotus will regenerate ? (what does "critter" mean ? I can't find the
word in my English-Dutch dictionary)

---------------------------------------------------------------------------------
GUERNSY

(Peter Johnston, Excelsa No.14, 1989, Carpobrotus in Guernsy)
restricted to coastal area

  climate:
Over the last 30 years the island has an  annual average air temperature
of 11 degrees celsius. The temperature around the coastal belt is around
one or two degrees celsius higher owing to the warming effect of the sea.
The species seems to thrive in a salt-laden atmosphere. The salt reduces
the chilling effect of the frost.

  soil:
C.edulis has colonised, in patches, sand dunes, shingle banks and the
littoral ofbays where the sea has cut into the head and loess left over
>from   the last Ice Age

  introduction:
Well established since at least the beginning of the century. Carre
remarked in 1862 that there were many Mesembryanthemum spp.

  other plant-species at site:
????
Umbilicus rupestris is found all over the island in virtually all
habitats, except on the coastal fringe with C. edulis.

  problems caused bij C. edulis:
Local conservationists and botanists do not favour C. edulis as it
is foreign import and tends to smother all vegetation were it grows
thickly. For this reason some areas have been systematically cleared
of the species.
Another problem with the species is that where it overhangs low cliff
areas, its weight causes subsidence off the cliff edge.

  remarks:
A study of the sites wher the species grows, started in the spring of
1986. In january 1987 a lot of the Carpobtotus edulis died because of
the severe winter. During the study some recovery has been measured.
The winter of 1987/1988 has been very mild with tempeatures above average.
How do the stands of Carpobrotus look in 1995 ? Does Carpobrotus show some
regeneration ?
-----------------------------------------------------------------------------------

PORTUGAL

(field trip: Mediterranean plants and landscape, 1995)

Amoreira, coastal area NW of Aljezur

  climate:
Mediterranean

  soil:
Dune-system near river mouth, on sandstone/shale bedrock. Sand partly
calcareous, partly leached out by rainwater, acid.

  introduction:
???

  other plant-species at site:
Malcolmia littorea -- Cistus salvifolius -- Polycarpon tetraphyllum --
Halimium calycinum -- Halimium halimifolium -- Sedum sediforme --
Juniperus phoenicea -- Corema album -- Lotus creticus -- Medicago marina --
Ononis natrix -- Stauracanthus genistoides -- Teucrium luteum --
Thymus camphoratus -- Armeria pungens -- Ammophilla arenaria --
Crucianella maritima

  problems caused by Carpobrotus edulis:
Carpobrotus edulis surrounds and overgrows a lot of other plant-species.
We saw that Thymus campheratus is completely overgrown by C.edulis. The
Lotus-species and Cistus salvifolius seem to be able to grow together
with C.edulis. These species are first being overgrown and then they come
up again through the Carpobrotus. Where the Juniperus is low, because of
the wind, Carpobrotus also grows over it. In places where the shrubs and
plants stand close together, and are higher, we found no Carpobrotus.

-----------------------------------------------------------------
;-) :-) (-:

Thanks for the information!!!!!!!!!!!!!!!!

Anja Henseler
[email-masked]