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BEN # 221
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No. 221 April 14, 1999
aceska@freenet.victoria.bc.ca Victoria, B.C.
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Dr. A. Ceska, P.O.Box 8546, Victoria, B.C. Canada V8W 3S2
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PLANT DIVERSITY IN BARKLEY SOUND [Part 2 of 3]
From: Martin L. Cody <mlcody@ucla.edu>
DISPERSAL AND COLONIZATION
On smaller islands where both colonization and extinction both
play a role, there is much lower predictability in species
numbers, with area (e.g. r**2 = 0.3-0.5). This is expected if
colonization rates are isolation-specific, with a minor role of
island size via a "target" effect. Four common dispersal
syndromes are represented on the islands:
1. FERNS ARE DISPERSED VIA DUST-LIKE HAPLOID SPORES that give
rise to a tiny short-lived gametophyte which produces an-
theridia or archegonia or both; after gametic union, it is
replaced by the often large and long-lived diploid
sporophyte whose sori in turn are the source of a further
generation of spores (e.g.Stebbins 1950). To date 9 species
have been encountered on the islands, but several others are
possibilities (Cody [W.J.] & Britton 1989). Of the eight
focal species, half are typical of shaded and moist forest-
floor sites, but some are rather more habitat specific; one
(Polypodium scouleri) occurs on coastal rocks, another
(Adiantum pedatum) on damp interior rocks, bracken (Pteri-
dium aquilinum) prefers dry, sunny banks, and a fourth
(Polypodium glycyrhiza), perennial but with annual fronds,
is largely epiphytic on tree trunks. All of the fern species
have rather regular and sigmoidal incidence functions (plots
of proportion of islands occupied versus island size) well
fitted by logistic regression, but island size at which
incidence begins to decline varies among species, and in
particular only those species with high leaf-specific weight
and minimal frond dissection (e.g., P. scouleri) persist on
the smaller islands.
2. At the opposite end of the vegetation gradient from the
forest ferns are PLANTS RESTRICTED TO THE SHORELINE ROCKS
AND BEACHES, of which there are some 30 characteristic
species (Cody 1998). Examples are Atriplex patula
(Chenopodiaceae), Honkenya peploides and Sagina crassicaulis
(Caryophyllaceae), Triglochin maritimum (Juncaginaceae), and
four grasses (Poaceae): Festuca rubra, Hordeum brachyan-
therum, Poa annua, Puccinnellia pumila. They differ in
habitat preference and are representative of the range of
shoreline sites; most are of wide Holarctic distribution,
and annual and perennial species are about equally repre-
sented in the guild. Most of these shoreline species dis-
perse by floating propagules, but in the two dry-rock
grasses wind, or possibly animals such as shoreline birds
may effect dispersal ("ectozoochory"), though they are but
modestly awned; of the two, Festuca is rhizomatous and
Hordeum is not. Incidence functions for some shoreline
species are reasonably monotonic with area, but others are
not.
3. A third guild is WOODY SHRUBS that occupy the ecotone be-
tween the forest and the shoreline. There is a choice from
perhaps two dozen species for this category, and examples
include four species of Rosaceae (Rosa, Rubus), 2 of
Caprifoliaceae (Lonicera, Sambucus), Grossulariaceae (Ribes)
and several Ericaceae (Arctostaphylos, Gaultheria, Vac-
cinium, Menziesia), among many others of narrower distribu-
tion (e.g. in Rosaceae, Amelanchier, Aruncus, Crategus,
Holodiscus, Physocarpus, Sorbus, Spiraea). These species
produce variously succulent berries and disperse via en-
dochory, using the locally common thrushes (Turdus
migratorius, Ixoreus naevius, Catharus ustulatus, C. gut-
tatus) and crows (Corvus) as dispersal agents. The fruits in
this guild span a range of sizes, colors, and maturation
phenologies, as in the three Rubus species which differ
conspicuously in timing and color of mature fruit: R. spec-
tabilis matures early (mid-June) with orange fruit, R.
parviflorus 2-3 weeks later with red fruit, and R. ursinus
later still with blackish fruit (Cody unpubl). Two other
Rubus spp., the alien R. procerus [=R. armeniacus] and R.
laciniatus, are rare on the islands. Incidence functions for
berry-producing shrubs decline with island area but at
different rates in different species. For examples, Lonicera
shows no effects of increased isolation, while the effects
are strong in Sambucus, which has much reduced incidence on
distant islands. The three Rubus species are ranked in
decreasing incidence spectabilis-parviflorus-ursinus, in all
cases with lower incidence on more distant islands; habitat
availability among these edge shrubs is not likely to vary
over island isolation, indicating perhaps a role for dif-
ferential dispersal and colonization.
4. Between the shoreline and the forest edge is a zone a few
meters wide where WEEDY HERBACEOUS PLANTS form a nearly-
continuous cover. This is the largest component of the flora
(ca. 100 species), with representatives of such families as
Apiaceae, Brassicaceae, Onagraceae, Polygonaceae, and
species of Asteraceae are especially common. Studies have
focussed on the latter family; most are short-lived peren-
nials, some are biennials and some annual. Some species have
distinct substrate and exposure preferences, and most are
anemochorous and disperse via achenes borne on a parachute-
like pappus. However, the most widely distributed species on
these islands, Achillea millefolia, matures later in the
season that do others in the guild and apparently disperses
as an ectozoochore when migrating shorelbirds fill the Sound
in late August. Two other composite species, Anaphalis and
Aster, also have non-anemochorous (and non-obvious) disper-
sal means. Incidence functions generally decline with
decreasing island size, but in widely variable fashion. At
the extremes, it is gradual in Achillea and precipitous in
Sonchus. Incidence in the three non-anemochorous species
(Achillea, Anaphalis, Aster) show little or no effect of
island isolation, but in the anemochores all show reduced
incidence on the more distant islands in line with expecta-
tions of declining colonization rates with increasing dis-
tance from source. The variety of incidence functions is
further extended by other species such as Matricaria
matricaroides , which occurs only on very small islands
(near and far), and is a good example of a supertramp
(Diamond 1975).
[Conclusion in BEN # 222]
VEGETATION CLASSIFICATION AND MAPPING IN THE ROCKY MOUNTAINS
SYMPOSIUM AND FIELD EXCURSION
From: Spribille_Toby/r1_kootenai@fs.fed.us
FIRST PRE-REGISTRATION NOTICE
Sponsored by the International Association of Vegetation
Science, North American Chapter, Glacier National Park, and the
Kootenai National Forest Botany/Ecology Programme.
Symposium - 29-30 June 1999 - Kalispell, Montana
Excursion - 1-2 July 1999
In recent years there has been a flurry of activity in the arena
of vegetation classification and vegetation mapping, ranging
from the introduction of a new vegetation classification system
by the Federal Geographic Data Commission and The Nature Conser-
vancy to advances being made in on-the-ground applications, from
Alaska to Colorado. Much of this work reflects an ongoing effort
to establish baseline data about vegetation, departing from the
past emphasis on site potential and concentrating on the exist-
ing vegetation in direct relationship to processes and environ-
ment. Unfortunately, much of this work is not very well known.
Even many vegetation scientists do not know about work being
carried out in other areas, and the users of vegetation class-
ifications have been confused about the relationship of the
newer vegetation classifications to habitat types and other
vegetation work done up until the present.
Against this background, vegetation scientists from across the
Rocky Mountains and Pacific Northwest have been invited to
present recent work on vegetation classification at a symposium
in Kalispell, Montana on the 29th and 30th of June, 1999. The
objectives of the meeting are to facilitate communication
amongst vegetation scientists, familiarize natural resource
managers with the existing vegetation classification systems as
well as recent developments in vegetation science in our region,
and solicit feedback from users on the ground, in a structured
but informal setting. The target audience includes vegetation
ecologists, foresters, botanists, wildlife biologists and other
professionals who use vegetation classifications on a daily
basis. We hope this exchange will shed light on some of the
following general topics:
Current issues:
--do new directives for natural resource management require new
perspectives of vegetation?
--taking stock of disturbance-dependent vegetation: do we have
an information void?
--acquiring the information needed in natural resource planning
(NEPA, Forest Practices Code)
Classifying vegetation:
--classification of all vegetation: aims and methods of
phytosociology
--field methods and table sorting: how results are arrived at
--syntaxonomy: bringing different vegetation classification
efforts ``onto the same page''
--relationship of phytosociology to habitat typing
--the National Vegetation Classification System
--landscape vegetation classification: aggregating vegetation
units at larger scales
--state of knowledge: what recent classifications have been
completed in the west?
--potential natural vegetation: new thoughts on old ideas
Applying classifications on the ground:
--how are vegetation classifications used in resource manage-
ment?
--vegetation inventory; what vegetation attributes should be
routinely collected for conservation and management purposes?
--how can baseline existing vegetation inventory be achieved by
land management agencies with limited budgets?
--vegetation mapping; integration of field inventory and GIS
techniques
--where do we need to go from here?
Two days of presentations will be followed by two days of field
excursions (limited to 25 people). On the 1st of July, Christian
Damm will show us alpine tundra vegetation in Glacier National
Park which he recently classified using Braun-Blanquet methods,
while on the second day (2 July) we will examine forest vegeta-
tion on the Kootenai National Forest, recently classified by Dan
Leavell on the basis of existing vegetation. We will discuss how
Glacier National Park and the Forest Service, respectively, will
be using these classifications, and how they could change the
way we view vegetation in these different environments.
In the course of the symposium, we will also learn about work
recently completed in Colorado, Alaska, British Columbia, and
other parts of the west. We will have a chance to pose our
questions to a panel of senior vegetation scientists including
members of the Ecological Society of America Vegetation Class-
ification Panel.
The organizing committee needs to get initial feedback on the
number of people interested in attending the symposium. If you
are intending to attend this meeting, please send an e-mail to:
Jack Triepke, Kootenai National Forest,
jtriepke/r1_kootenai@fs.fed.us (IBM: jtriepke/r1,kootenai). Your
name will be added to a mailing list to receive future mailings
about this symposium.
A DRAFT AGENDA listing the scheduled presentations will be
forthcoming and will be mailed out to those who respond to this
posting. Individuals interested in presenting posters or
scheduling brief presentations, please contact Toby Spribille
at 406.882.4451 or e-mail: <tspribille/r1_kootenai@fs.fed.us> as
soon as possible. Formal registration in the symposium will
carry a modest fee, not expected to exceed US$60.00 per person.
WORLD WEEDS DATABASE ON CD-ROM
From: "P. Bacon" <phil.bacon@plant-sciences.oxford.ac.uk>
The World Weeds Database is based on the information contained
in the book "A Geographical Atlas of World Weeds" by Leroy Holm,
Juan V. Pancho, James P. Herberger and Donald L. Plucknett,
which was published in 1979.
The book is a comprehensive list of weed species of the world
and their distribution after a research-work of ten years. Even
though it does not include all the species for any geographical
region it is a good information source for workers and scien-
tists.
The purpose of the database is to make it possible to retrieve
valuable information from this book and make it available for
foresters or any other person who might be interested in knowing
the distribution of the most common and worst weeds. The World
Weeds Database displays information on nearly 7000 weed species
around the world according of its rank of importance. The
database contains Genus, Family and Species names as well as
taxonomic authorities.
This database is a development of work originally done in 1994
and 1995, supported by The Natural Resources Institute, Long
Ashton Research Station, The Forestry Research Program (OFI) and
the UK Overseas Development Administration.
We've now got this copied to CD-ROM. Full spec can be viewed at:
http://w3.to/weeds/
Copies available from here at 27 British Pounds or equivalent.
Please pass this message on to anyone who might be interested.
Dr. P. Bacon, Oxford Forestry Institute
Department of Plant Sciences, University of Oxford
South Parks Road, Oxford OX2 3RB - UK
fax: 01865 271036 phone: 01865 271035
email: pbacon@ermine.ox.ac.uk
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