| BEN |
| BOTANICAL ELECTRONIC NEWS |
|---|
| ISSN 1188-603X |
| No. 430 December 3, 2010 | aceska@telus.net | Victoria, B.C. |
|---|
You are invited to attend Invasion of the Aliens, the Invasive Plant Council of BC's (IPCBC) public forum being held January 18th and 19th, 2011. This exciting event will take place at the Delta Vancouver Airport Hotel in Richmond, BC.
Participants of Invasion of the Aliens will have the opportunity to engage in thought-provoking discussions, listen to dynamic speakers during plenary sessions, check out conference displays and posters, and meet and greet others during nibble and network sessions. Speakers will discuss current threats to BC, North American collaborations, invasive species impacts on BC resources, Canada's response to invasive species, and social marketing.
You are also invited to attend the post-forum workshop, Making it Work...Locally, on January 20th, 2011. Space is limited, so be sure to register early!
Call for posters is now open, and don't forget to book your conference display space early!
You can also register easily from the IPCBC website http://www.invasiveplantcouncilbc.ca
We look forward to seeing you at Invasion of the Aliens!
IPCBC Staff #104 - 197 North Second Ave. Williams Lake, BC V2G 1Z5 Ph: 1-888-WEEDSBC or 1-250-392-1400 Web: www.invasiveplantcouncilbc.ca
In 2008, Parks Canada began a project to restore an ecologically functioning coastal dune ecosystem at Wickaninnish Bay within Pacific Rim National Park Reserve. A combination of invasion by European and American beachgrasses, (Ammophila arenaria [L.] Link & Ammophila breviligulata Fern.), accumulation of logging debris, and advanced encroachment by woody species has fully or partially blocked the transport of sand to and within the large dune complexes at Wickaninnish Bay. In turn, this produces a cascade of ecological effects that continues to convert open dunes to forests resulting in the loss of native dune flora and fauna. Parks Canada's dune restoration project focuses on the restoration and maintenance of the open coastal dune ecosystem.
Although the exact date and method for the introduction (accidental, purposeful) and spread of Ammophila spp. is uncertain, what is clear, is that by 1960 it was a dominant dune species within the Long Beach unit of Pacific Rim National Park Reserve. Ammophila spp. forms tight clonal clusters trapping the sand coming off the beach. Over time these areas develop the parallel rows of dunes and hollows that characterize Ammophila spp. dominated coastal dunes. This is the characteristic geomorphology of dune systems on the east coast of North America. On the west coast of Vancouver Island, the development of dune rows was further facilitated by an accumulation of logging debris particularly in the period prior to 1970. The stabilization of sand facilitates an encroachment of woody stemmed plants eventually leading to the development of a krummholz forest on the foredunes and previously open backdunes.
At present, 50% of the available dune area at Wickaninnish is still active with sand movement, 14% is partially blocked but can still support almost all the dune flora, while 34% is completely blocked and exhibits a declining dune flora (Table 1). Examination and analysis of historic aerial photographs indicates that all dune complexes at Wickaninnish will be completely closed off by 2030.
The dune restoration project seeks to restore and maintain the native dune flora to those areas at Wickaninnish that have open and partially open dunes and to use this knowledge to determine the feasibility of expanding the restoration to closed dunes and Ammophila spp. covered fore- and backdunes. On Vancouver Island, the dominant native beach grass is coastal ryegrass, Leymus mollis (trin.) Pringel, (syn.: Elymus mollis Trin.). Unlike Ammophila spp., sand accumulation with L. mollis is much less and dunes are more dynamic through time. It seldom grows over the backdunes, leaving them open to sand movement. Typically, we record a higher diversity and abundance of co-existing native dune species in areas dominated by L. mollis. The dune complexes at Wickaninnish Bay should naturally feature an irregular pattern of dune hummocks and slacks with intermittent swards of L. mollis and open areas of mobile sand. This is the ecological target for restoration.
The primary method of restoration is Ammophila spp. and spruce tree (Picea sitchensis [Bong.] Carr.) removal. This will prevent the cascade of ecological events that occurs after dunes are closed to sand movement. Methods vary from hand pulling to brush and chainsaws to specially equipped bucket excavators. Of the originally targeted 25,488 sq m, approximately two-thirds have been removed (16,985 sq m) leaving 7,603 sq m left to treat. >From examination and analyses of historical aerial photographs, the approximate lateral expansion rate of Ammophila spp. over the foredunes has never exceeded 10.9 m per year while spruce expansion has never exceeded 8.3 m per year. Hence, the maintenance of the open foredune after the initial restoration should not require a tremendous effort. Visually, the response of the dune plants has been promising. The official post-treatment sampling is slated for 2012-2013, however, this may be moved up given the faster than expected progress. This restoration work forms a platform for a number of research and monitoring programs. These include: . Re-introduction of pink sand verbena (Abronia umbellata), a Schedule 1 species at risk, from seeds propagated from the Clo-oose population (Fairbarns, BEN No. 428, October 21, 2010: http://www.ou.edu/cas/botany-micro/ben/ben428.html ) . Studies into the habitat requirements of Lathyrus littoralis and Abronia umbellata . Studies into coastal erosion and geomorphology of dunes in response to restoration - University of Victoria (Dr. Ian Walker) . Competition-productivity studies of Leymus mollis and Ammophila spp. . Vegetation monitoring programs in the fore- and backdune
>From the outset a large outreach component was built into the project. The location of the Wickaninnish dunes with its high visitor traffic provides an excellent opportunity for onsite education and visitation into the dune habitat. Outreach includes guided dune walks, Ammophila spp. pulls (cf. BEN # 427 http://www.ou.edu/cas/botany-micro/ben/ben427.html ), school tours, and onsite interpretation during all major restoration events such as the excavation and disposal of Ammophila spp. This outreach will continue into the future with new exhibits in the renovated interpretation centre.
This paper describes the reproductive characteristics of 93 neophytes (alien species introduced after 1500 A.D.) of the flora of the Czech Republic and compares trait values between naturalized invasive and naturalized non-invasive neophytes. Species were sampled and seed collected in the field from multiple localities in the Czech Republic. Traits related to seed production (propagule number per plant and per population), dispersal (propagule size, length/width ratio and weight; buoyancy; epizoochory; terminal velocity) and establishment (germination; seedling relative growth rate; seedling establishment) were measured for each species either in the field, in a common garden experiment or in the laboratory. Invasive species significantly differ from naturalized non-invasive species in propagule length/width ratio (by having lower ratio, i.e. more rounded propagules) and fecundity (invasive species are more fecund, both per individual plant and in terms of the population propagule production). Invasive species have proportionally fewer seedlings establishing in the autumn and better capacity for dispersal by wind than non-invasive species. The results for several traits differ depending on whether or not the effect of phylogeny is included in analytical models. Considering species relatedness expressed as a taxonomic hierarchy, invasive species have lighter propagules and higher population propagule numbers, and marginally significantly differ in producing more propagules per plant and having higher capacity for dispersal by water. We found that most variation in invasiveness is linked to variation among species within genera. This distribution of relatedness means that predictions of whether a species will become invasive cannot be based on traits of the relatives of the given species at higher taxonomic levels. The distinction made in this paper, i.e. invasive species vs. naturalized but non-invasive species, can potentially contribute to a deeper understanding of the role of traits associated with invasiveness because the crucial transition from the naturalized to invasion stage is rarely addressed in invasion ecology
Subscriptions: http://victoria.tc.ca/mailman/listinfo/ben-l.
Send submissions to aceska@telus.net
BEN is archived at http://www.ou.edu/cas/botany-micro/ben/