News/Reports
Trial Island Invasive Plant Species Management Plan
Prepared by: Chris Barrett and Carrina Maslovat, R. P. Bio. Telephone: — email–
Prepared for: Ecosystems Branch BC Ministry of Environment
Table of Contents
Previous Invasive Species Management3
Invasive Woody Species on Trial Island. 4
1. English ivy (Hedera helix)5
2. Scotch broom (Cytisus scoparius)7
4. Spurge-laurel (Daphne laureola)11
5. English hawthorn (Crataegus monogyna)13
6. Himalayan blackberry (Rubus discolor)15
7. English holly (Ilex aquifolium)17
8. Cotoneaster (Cotoneaster sp.)18
9. Common privet (Ligustrum vulgare)20
10. Non-native yew (Taxus sp.)21
Monitoring and Future Invasive Species Control22
Disposal of Invasive Species. 23
Appendix 1. List of Species at Risk on Trial Island. 28
See the complete PDF of this document at:
Revised Feb 2008- Trial Island Invasive Plant Species Management Plan
List of Figures
Figure 1. Concentrations of English ivy on Trial Island (2007)5
Figure 3. Location of mature Gorse on Trial Island prior to 2007 surveys. 10
Figure 5. English hawthorn on Trial Island (2007)14
Figure 6. Location of mature Himalayan blackberry on Trial Island prior to 2007 surveys.16
Figure 7. English holly on Trial Island (2007)17
Figure 9. Common privet on Trial Island (2007)20
Figure 10. Non-native yew on Trial Island (2007)21
Figure 11. Monitoring areas on Trial Island. 23
Acknowledgements
Many thanks to Matt Fairbarns and Chris Barrett for providing the details of the work that has already been completed on Trial Island and providing guidance on the direction of future work. Thank you to Brenda Costanzo for providing assistance during the writing of this report.
quantity of habitat for many species at risk which occur on Trial Island including: Golden Paintbrush, Seaside Bird’s-foot Trefoil, Dense-flowered Lupine, Bear’s-foot sanicle, Coastal Scouler’s Catchfly, Purple Sanicle, White-top Aster, California Buttercup, Spanish-clover, Elegant Rein-orchid, Black Knotweed, Common Ringlet and Taylor’s Checkerspot (Fairbarns and Kohler 2006). Other species restricted to poorly drained vernal pools (e.g. Banded Cord-moss, Rosy Owl-clover, Macoun’s Meadowfoam, Victoria Owl-clover, Carolina Meadow-foxtail, Pigmyweed and Nuttall’s Quillwort) or rocky shorelines (e.g. Beach Sand-spurry) are less threatened by invasive woody species (Fairbarns and Kohler 2006).
Approximately 1/3 of the 200 species reported from Trial Island are non-native and about 40 of these species are moderate to highly invasive (Fairbarns and Kohler 2006). There are currently no known effective controlmeasures for invasive grass and forb species (Fairbarns pers. comm. 2008; Roemer pers. comm. 2008). Invasive woody species found on Trial Island are more easily controlled and are the focus of this management plan. Target species includeEnglish ivy (Hedera helix), Scotch broom (Cytisus scoparius), Gorse (Ulex europaeus), Cotoneaster (Cotoneaster spp.), Himalayan blackberry (Rubus armeniacus), Spurge-laurel (Daphne laureola), English holly (Ilex aquifolium), Common privet (Ligustrum vulgare), English hawthorn (Crateagus monogyna) and an unidentified species of Yew (Taxus sp.).
The risk of damage to species at risk from invasive species management is also a significant threat. Poorly planned invasive species removal can harm plants at risk through excessive trampling, improper removal facilitating spread of invasives, piling of slash and creating excessive soil disturbance. Properly planned invasive species management is essential for minimizing these risks.
Previous Invasive Species Management
There have been attempts to control invasive species on Trial Island for over a decade, although early efforts were volunteer based and poorly documented. In 2003, volunteers were co-ordinated using a more rigorous approach. A work analysis prepared in 2005 determined that the scale of the work exceeded the capacity of volunteers. In 2005, the Garry Oak Ecosystems Recovery Team (GOERT) submitted a funding proposal to the Habitat Stewardship Program (HSP), using in-kind assistance from BC Parks as matching funds (Fairbarns 2007).
Funding from HSP was received for 2006/2007. A BC Conservation Corp work crew, hired by BC Parks, removed invasive shrubs from much of the island before March of 2007. Invasive species were not removed in core areas near the center of the island where invasive shrub density was highest (Fairbarns 2007).
Background
There are three distinct landowners/landmanagers on Trial Island: Canada Coast Guard; provincial Crown land leased to a communications company; and provincial ecological reserve. Canada Coast Guard maintains a light station on the island and there is a resident lightkeeper on the island. Seacoast Communications has a series of antennae on the island, which require infrequent maintenance. Trial Islands Ecological Reserve was established to: 1) preserve representative examples of British Columbia’s ecosystems; 2) protect rare and endangered plants and animals in their natural habitat; 3) preserve unique, rare or outstanding botanical, zoological or geological phenomena; 4) perpetuate important genetic resources; and 5) allow scientific research associated with the natural environment (BC Parks 2008). Permits are required in order to land on the ecological reserve (BC Parks 2008).
Trial Island has one of the greatest concentrations of species at risk in all of Canada, including: 1 moss, 18 vascular plants and 2 butterflies (list of species at risk included in Appendix A). Nine of the vascular plant species, one of the butterflies, and the moss are listed by COSEWIC as being either endangered, threatened or of special concern. Status reports are in progress for two other plant species including a newly described species, Victoria owl-clover (Castilleja victoriae).
Invasive species have been identified as one of the most serious threats facing plant species at risk in maritime meadows, woodlands and vernal pools/ephemeral wetlands associated with Garry oak ecosystems (Parks Canada Agency 2006a; 2006b; 2006c). Invasive species decrease both the quality and quantity of habitat for many species at risk which occur on Trial Island including: Golden Paintbrush, Seaside Bird’s-foot Trefoil, Dense-flowered Lupine, Bear’s-foot sanicle, Coastal Scouler’s Catchfly, Purple Sanicle, White-top Aster, California Buttercup, Spanish-clover, Elegant Rein-orchid, Black Knotweed, Common Ringlet and Taylor’s Checkerspot (Fairbarns and Kohler 2006). Other species restricted to poorly drained vernal pools (e.g. Banded Cord-moss, Rosy Owl-clover, Macoun’s Meadowfoam, Victoria Owl-clover, Carolina Meadow-foxtail, Pigmyweed and Nuttall’s Quillwort) or rocky shorelines (e.g. Beach Sand-spurry) are less threatened by invasive woody species (Fairbarns and Kohler 2006).
Approximately 1/3 of the 200 species reported from Trial Island are non-native and about 40 of these species are moderate to highly invasive (Fairbarns and Kohler 2006). There are currently no known effective controlmeasures for invasive grass and forb species (Fairbarns pers. comm. 2008; Roemer pers. comm. 2008). Invasive woody species found on Trial Island are more easily controlled and are the focus of this management plan. Target species includeEnglish ivy (Hedera helix), Scotch broom (Cytisus scoparius), Gorse (Ulex europaeus), Cotoneaster (Cotoneaster spp.), Himalayan blackberry (Rubus armeniacus), Spurge-laurel (Daphne laureola), English holly (Ilex aquifolium), Common privet (Ligustrum vulgare), English hawthorn (Crateagus monogyna) and an unidentified species of Yew (Taxus sp.).
The risk of damage to species at risk from invasive species management is also a significant threat. Poorly planned invasive species removal can harm plants at risk through excessive trampling, improper removal facilitating spread of invasives, piling of slash and creating excessive soil disturbance. Properly planned invasive species management is essential for minimizing these risks
Previous Invasive Species Management
There have been attempts to control invasive species on Trial Island for over a decade, although early efforts were volunteer based and poorly documented. In 2003, volunteers were co-ordinated using a more rigorous approach. A work analysis prepared in 2005 determined that the scale of the work exceeded the capacity of volunteers. In 2005, the Garry Oak Ecosystems Recovery Team (GOERT) submitted a funding proposal to the Habitat Stewardship Program (HSP), using in-kind assistance from BC Parks as matching funds (Fairbarns 2007).
Funding from HSP was received for 2006/2007. A BC Conservation Corp work crew, hired by BC Parks, removed invasive shrubs from much of the island before March of 2007. Invasive species were not removed in core areas near the center of the island where invasive shrub density was highest (Fairbarns 2007).
HSP funding was also received for 2007/2008. Invasive species removal was done by a much smaller crew over a longer period of time rather than a short period of intense activity by a larger crew. Seven target species at risk (including COSEWIC listed and provincially-listed) were marked using temporary markers on the island and a botanist removed all reproductive-age invasive species within two meters of each occurrence. The crew removed all Scotch broom, Gorse and Spurge-laurel plants over 30 cm tall from August to October 2007 (Fairbarns 2007; Barrett pers. comm. 2007). The locations of the species at risk occurrences were also mapped and kept on file with the Ecosystems Branch of the BC Ministry of Environment (Fairbarns 2007).
Methodology
In order to prepare this invasive plant species management plan, Trial Island was surveyed for all woody non-native plants on October 21PstP 2007. Priority was given to those species identified as the greatest threats by the GOERT Decision Support Tool (Fairbarns and Kohler 2006), based on their density within invaded areas and their degree of establishment. In addition, species that are easily controlled and currently have a low degree of invasion but with the potential for future harm are targeted. “Satellite” locations where invasions are just beginning and can be easily controlled are also priorities. The locations of invasive species were recorded using a hand-held GPS and the locations mapped using OZI-Explorer.
Invasive Woody Species on Trial Island
The following section describes each invasive shrub species, provides a description of the distribution on Trial Island and outlines appropriate management techniques including an evaluation of the work conducted to date. Disposal of invasive biomass and monitoring protocol to identify re-invasion are included in separate following sections.
A permit is required prior to any work in BC Parks Ecological Reserves, including the application of herbicide.
1. English ivy (Hedera helix)
Species description
English ivy is a climbing vine with leathery, glossy evergreen leaves. The clustered flowers are greenish-yellow and the fruits are blue-black berries. With support, the vines can reach up to 30 meters tall (Douglas et al. 1998).
English ivy is extremely fast growing and can form dense patches, shading out native plants and preventing germination of their seeds. Trees may be weakened or killed when English ivy grows over their trunks and branches in its climbing form (GOERT 2003).
Distribution
English ivy is distributed throughout Trial Island. Some portions of the island have been heavily invaded and in the densest patches, few native plants survive. In other areas, English ivy exists in small pockets or as an understory to native shrubs. In areas where the English ivy grows vertically (i.e. over a beach house on the west side of the island, over small trees or over exposed rock outcrops), the vines flower and produce fruit.
See the complete PDF of this document at:
Revised Feb 2008- Trial Island Invasive Plant Species Management Plan
Appendix 1. List of Species at Risk on Trial Island
(Used with permission from Fairbarns and Kohler 2006)
| Latin Name | English Name | COSEWIC Status | Provincial Rank and Listing | Global Rank |
| Mosses | ||||
| Entosthodon fascicularis | Banded cord-moss | Special Concern | S2-Red | G4G5 |
| Vascular Plants | ||||
| Castilleja levisecta | Golden paintbrush | Endangered | S1-Red | G1 |
| Lotus formosissimus | Seaside birds-foot lotus = Seaside bird’s-foot trefoil | Endangered | S1-Red | G5 |
| Lupinus densiflorus var. densiflorus | Dense-flowered lupine | Endangered | S1-Red | G5T4 |
| Orthocarpus bracteosus | Rosy owl-clover | Endangered | S1-Red | G3? |
| Sanicula arctopoides | Bear’s-foot sanicle =Snake-root sanicle | Endangered | S1-Red | G5 |
| Silene scouleri ssp. grandis | Coastal Scouler’s catchfly | Endangered | S1-Red | G5TNRQ |
| Limnanthes macounii | Macoun’s meadowfoam | Threatened | S3-Blue | G3 |
| Sanicula bipinnatifida | Purple sanicle | Threatened | S2-Red | G5 |
| Sericocarpus rigidus = Aster curtus | White-top aster | Threatened | S2-Red | G3 |
| Castilleja victoriae | Victoria owl-clover | Status report in progress | [proposed for ranking as S1] | [proposed for ranking as G1] |
| Ranunculus californicus | California buttercup | Status report in progress | S2-Red | G5 |
| Alopecurus carolinianus | Carolina meadow-foxtail | S2-Red | G5 | |
| Crassula aquatica | Pigmyweed | S3-Blue | G5 | |
| Isoetes nuttallii | Nuttall’s quillwort | S3-Blue | G4? | |
| Lotus unifoliolatus var. unifoliolatus | Spanish-clover | S2S3-Blue | G5T5 | |
| Piperia elegans | Elegant rein orchid | S3-Blue | G4 | |
| Polygonum paronychia | Black knotweed | S3-Blue | G5 | |
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