| BEN |
| BOTANICAL ELECTRONIC NEWS |
|---|
| ISSN 1188-603X |
| No. 183 February 12, 1998 | aceska@victoria.tc.ca |
|---|
Where: University of Victoria, Elliot Lecture Wing
When: Saturday March 7 from 9:00 a.m. to 5:00 p.m.
Program:
Displays, workshops, plant sale, etc.
Tickets are $15.00 at the door/ $8.00 Students and un-waged, or $12.00 in advance at The Field Naturalist, Swan Lake Nature House, and Dig This.
For more information contact
Ammophila arenaria was introduced to the west coast of North America in l868 to stabilize dunes in the San Francisco area. The introduction came from Australia where it had been earlier introduced from Europe. Because of its ability to thrive under conditions of high wind and sand burial, the grass spread rapidly, both by natural means and through its steadily increasing use in sand stabilization projects.
One result of the establishment and spread of Ammophila was the development, by about l950, of a massive foredune system along most of the dune areas of the Pacific Northwest coast. The vegetation of existing foredunes was overwhelmed and the foredunes built to a much larger size, while on the central Oregon coast, where previously there had been no foredune, one of massive proportions came into existence.
Large areas of active dunes were also stabilized through extensive planting programs. Examples include the Clatsop Plains at the mouth of the Columbia River in Oregon where decades of grazing and cultivation of the dune field resulted in extensive dune rejuvenation (l940's), and the active dune fields south of Siuslaw River at Florence, Oregon (l950's). A congener, Ammophila breviligulata Fern., native to the east coast and the Great Lakes Region, had been used on the Clatsop Plains and for stabilization plantings on a few areas of the Washington coast. It is virtually indistinguishable from A. arenaria in its general morphology and growth habits.
A long-term result of this domination by a single, vigorous species with 100% ground cover has been the suppression of many of the numerous native, dune-building species: Elymus (Leymus) mollis, Abronia latifolia, Covolvulus (Calystegia) soldanella, Carex macrocephala, Glehnia leiocarpa, Lathyrus littoralis, Poa macrantha, and others. None are immediately threatened with extinction (except, perhaps, Abronia umbellata, at least in the northwest) but they are much less seen than in former times. Ammophila is also seen by some to be a long-term threat to the scenic and recreational values of the extensive Oregon coastal dune fields. This is debatable.
The species is uniquely well-adapted to areas where large amounts of sand are moved by strong, unidirectional winds. It thrives on burial, which is necessary for vigorous growth and flowering. Where burial ceases, plant cover is reduced and the plant eventually dies. Studies in Holland suggest that this senescence and eventual death may be due to plant-parasitic nematodes that reduce root length and root hair formation. Continuous sand burial stimulates new root production, enabling vigorous growth to continue.
Ammophila achieves dominance by the production of great numbers of vertical tillers and culms, resulting in heavy foliage cover. Elymus mollis, the principle native dune-building grass, puts primary growth energy into horizontal rhizome production with vertical shoots more spaced, creating a more open cover in which other species can colonize. On the coastal dunes of western Europe, where it is native, Ammophila does not achieve the same overwhelming dominance. This may be due to wind regime, plant competitors, soils, or other factors.
The species is widespread along the coast of western Europe and around the Mediterranean Sea, between approximately Latitude 30N to 60N. It has been introduced into virtually every British colonial settlement within its latitudinal tolerance range, including southeast and southwest Australia, New Zealand, South Africa, the Falkland Islands, and Norfolk Island. It has been planted widely in Japan and has been reported from Argentina and Chile. In the southern hemisphere its northern limits lie at Latitude 30S to 32S. Observations at these latitudes (Sydney, Perth, Port Elizabeth, Capetown) indicate generally poor growth and sparse flowering.
In response to concerns about scenic landscape destruction and native plant extinction, there has been experimentation with various methods to control or eradicate Ammophila. None (burning, covering, mowing, salting, poisoning) has proved effective and/or practical. Digging is effective, but very expensive. At the Lanphere-Christensen Dunes Preserve on the northern California coast (Arcata) a program was initiated in l992 to remove Ammophila, by digging, from 4 ha of foredune. The cost in l994 was $20,000/ha.
Recent studies by the author, based on a 30-year transect, indicate that on the "back crests" and lee slopes of the foredune it is likely that Ammophila will eventually be replaced by native shrub and tree species. The native sand pioneer species will find refuge in blowouts occurring away from the beach areas, while Ammophila will continue to dominate the windward foredune slopes and foredune crest blowouts.
Further reading:
This is the list of species that I am trying to collect information on. I am collecting information on control methods (i.e. biological, chemical, cutting, pulling, burning, etc.) and management programs that have worked or failed. My goal is to find the most environmentally sensitive management program that provides effective control of the following weeds:
If you have any information that seems relevant please contact me.
This book is a comprehensive reference guide to Canadian vegetables. It covers both commercial and home garden crops and includes all of the major, minor, and potentially new vegetables of Canada. The book provides information on about 100 vegetables. For each vegetable the authors discuss the names, description and taxonomy, uses, importance, cultivation notes, etc. The bibliography contains over 600 references. A long list of vegetable-oriented web sites is given for the Internet browsers.
The "Vegetables of Canada" is a sibling publication to the "Culinary herbs" (see BEN # 180). The format is similar, although the typography of the "Culinary herbs" is more pleasing. The illustrations of the vegetables are taken over from older, copyright-free publications (like many illustrations in the "Culinary herbs"), but they are used more as a clip-art rather than really functional full illustrations. There are only several original drawings (e.g., Oriental cabbages, difference between rutabaga & turnip, insect-resistant potato) that gives more information and detail and I wish there were more of those in this book.
The book is a good reference to the vegetables cultivated in a temperate climate and it is an important addition to the literature on economic plants.
A short chapter of "Vegetables of Canada" is available for viewing at the NRC Research Press Web site: http://www.nrc.ca/cisti/journals/40700/veg_e.html
Sitka spruce (Picea sitchensis) is an important commercial tree of the Pacific Northwest coastal forests. This publication deals with the biology, ecology and silvicultural aspects of this species. The authors deal in depth with the ecology of Sitka spruce, with the response of the tree to certain ecological factors, and with its reproductive biology. In the main chapter the authors discuss silvicultural questions such as original plantation spacing, juvenile spacing, and fertilization to shorten the rotation period of second-growth coastal spruce stands. The book is based on a thorough literature survey and gives over 830 references, with a high proportion of publication published after 1990. This is an important book for anyone interested in the ecology, biology and silviculture of Sitka spruce.
This is a new edition of the classical reference on pteridophyte hybrids. This edition lists about 1,100 names related to pteridophyte hybridity backed by almost 700 references.
Submissions, subscriptions, etc.: aceska@victoria.tc.ca. BEN is archived at http://www.ou.edu/cas/botany-micro/ben/