A Spreading Menace: Invasive Plants in Your Backyard presented by: Blaine T. Spellman
Presentation Outline Introduction to invasive plant science and management. Invasive plants of concern for the Kena Peninsula. What you can do to help!
Presentation Outline Introduction to invasive plant science and management Invasive plants of concern on the Kenai Peninsula. What you can do to help!
Definitions Native plants - occur in a particular place without the assistance of humans. Non-native plants - originate from foreign habitats and their introduction is facilitated through human action. * Sweetclover (Melilotus alba) is a non-native plant in Alaska
Non-Native Plants - Good or Bad? Many non-native plants were brought intentionally for beneficial purposes: Common dandelion (Taraxacum officinale) food crop Pineapple weed (Matricaria discoidea) medicinal herb Clover species (Trifolium sp.) cover crop However, when introduced into an area outside their native range, non-native plants may have unintended negative impacts. common dandelion pineapple weed Slide courtesy of Jeff Heys white clover
Defining an invasive plant Invasive plants - are non-native species that spread outside cultivated areas and have negative impacts to the economy, environment, and/or human well-being.
Why should you care about invasive plants? What do you think? narrowleaf hawksbeard yellow toadflax canada thistle oxeye daisy oxeye daisy
Negative Impacts: Why should you care about invasive plants? Biodiversity - non-native plants are a leading cause of world-wide extinctions Ecosystem Services - non-native plants affect recreation, aesthetics, and spiritual properties of land Economy - non-native plants cost the U.S. economy around $137 billion annually Agriculture - non-native plants compete with crops, lower food supplies, and can kill livestock Control - non-native plants are extremely hard to control and often require the use of herbicides narrowleaf hawksbeard canada thistle yellow toadflax oxeye daisy oxeye daisy
Alaskan Situation Alaska is at Risk Cold Climate Alaska is Unique Small human population Few established native plant species The majority of natural land in Alaska is devoid of non-native species global warming trend linked to warmer winters and longer growing seasons increases in human population, tourism, and development Alaska might be more hospitable and accessible to non-native plant species
Non-Native Plants in Alaska 50% increase in non-native plants species since 1941 (Carlson and Shephard) 283 non-native plant species have been found in Alaska 60 non-native plant species currently have the potential to impact natural habitats (ANHP 2005) But do they grow in natural habitats?
Sweetclover infestation along the Stikine River M. Shephard
How might invasive plants impact native vegetation in natural habitats? Competition: no sweetclover infestation Invasive competition may limit resources to native plants by reducing water nutrients light space Invasive competitions could: decrease the abundance or cause local extinctions of native plant species sweetclover infestation
Losing Alaska s wildflowers?
Losing berry picking habitat?
All things are linked
Decreases in animal populations? Orange hawkweed snowshoe hare lynx Dominates grass/herb communities! Altered diet. Potential lower reproduction? Fewer hares. Potentially fewer lynx?
Decreases in animal populations? reed canary grass Black Bear sockeye Less food, less bears? Loss of salmon spawning beds? Displaces native grass/sedge and clogs streams! Less food in the freezer, need more $$$
Presentation Outline Introduction to invasive plant science and management Invasive plants of concern on the Kenai Peninsula What you can do to help!
Invasives on the Kenai There are 21 invasive species on the Kenai Peninsula Many invasives were brought to the Kenai by accident in seed mix, gravel, potting soil, hay, etc. : Exs. hempnettle, canada thistle, perennial sowthistle
Invasives on the Kenai Some invasive plants were brought to the Kenai for use as forage crops or green manure: Exs. reed canary grass, bird vetch, white sweetclover
Invasives on the Kenai Many invasive plants were likely brought to the Kenai as ornamentals for gardens: Exs. butter and eggs, common tansy, orange hawkweed, oxeye daisy, ornamental jewelweed
Butter and Eggs (Linaria vulgaris) Butter and Eggs Facts: Brought to Alaska as an ornamental. Perennial that aggressively spread via roots and grows up to 2.5 feet tall. displaces native vegetation, livestock forage, and wildlife habitat. Mildly toxic to wildlife. A single plant can produce up to 30,000.
Common Tansy (Tanacetum vulgare) Common Tansy Facts: Brought to Alaska as an ornamental. Perennial that aggressively spread via roots and grows up to 6 feet tall. displaced native vegetation, livestock forage, and wildlife habitat. Toxic to wildlife. A single plant can produce up to 50,000 seeds.
Orange Hawkweed (Hieracium aurantiacum) Orange Hawkweed Facts: Brought to Alaska as an ornamental. Perennial that aggressively spreads via roots and forms a dense mat that displaces native vegetation and turf in lawns. Spreading all over the Kenai Peninsula via wind dispersed seed.
Oxeye Daisy (Leucanthemum vulgare) Oxeye Daisy Facts: Brought to Alaska as an ornamental and often used in wildflower seed mixes. Perennial that grows up to 3 feet tall and spreads through roots and seed. A single plant can produce up to 4,000 seed. Can form dense stands that displaces native vegetation. unpalatable to livestock
Ornamental Jewelweed (Impatiens glandulifera) Ornamental Jewelweed Facts: Brought to Alaska as an ornamental. Annual that grows up to 6 feet tall. Grows along streams, wetlands, and disturbed areas. Forms dense stands that displace native vegetation. Spreads solely by seed, up to 2,500 per plant. Seeds spread readily by water and can spread up to 3 miles a year.
Presentation Outline Introduction to invasive plant science and management Invasive plants of concern for the Kenai Peninsula. What you can do to help!
What can you do? Prevention is the best solution to invasives! Make sure the plants (or seed mixes) you use for gardening are not invasive species. If you plan on using local gravel/sand/soil, then make sure the source does not have invasive weeds. Use weed-free products (i.e. hay and straw). After working in weed infested areas, wash equipment and clothes to prevent transportation of seeds.
What can you do? Education about invasive species: Learn the native and non-native plants around your house, neighborhood, and town. SPREAD THE WORD! Tell your family and friends about the problems associated with invasive species. There are K-12 curriculums available for educators interested in teaching about invasive species.
What can you do? Manage and control invasive weeds. Determine the location of weeds on your property and in your community. Conduct community wide weed pulls. Develop a management plan with the Kenai Peninsula Cooperative Weed Management Area to eradicate weeds in your community.
Acknowledgments Funding for this talk was provided by the U.S. Forest Service and the Homer Soil and Water Conservation District.