Invasive and Noxious Weeds on the Gaviota Coast

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1 Invasive and Noxious Weeds on the Gaviota Coast Gaviota Coast Planning Advisory Committee Meeting # 23: Resources Stewardship and Open Spaces December 1, 2010 David Chang County of Santa Barbara Agricultural Commissioner s Office

2 What is a weed? Anthropocentric: a weed is a plant out of place; interferes with management objectives Biogeographical: : an invasive weed spreads into areas where it is not native Ecological: : a non-native native plant introduced to an ecosystem that changes the structure and function of that ecosystem

3 Defines an invasive weed as: Non-native native to the ecosystem under consideration Spreads into wildlands and displaces or hybridizes with native species or alters biological communities or ecosystem processes

4 California Agricultural Law FAC "Noxious weed" means any species of plant that is, or is liable to be, troublesome, aggressive, intrusive, detrimental, or destructive to agriculture, silviculture, or important native species, and difficult to control or eradicate, which the director, by regulation, designates to be a noxious weed.

5 California Agricultural Law FAC 5004 continued In determining whether or not a species shall be designated a noxious weed for the purposes of protecting silviculture or important native plant species, the director shall not make that designation if the designation will be detrimental to agriculture.

6 California Agricultural Law Ratings are used to prioritize noxious weeds A - High priority, rare or not found in California B - Medium priority, more common, but not widespread C - Still regulated, but lower priority, usually common

7 California Agricultural Law FAC 403. The department shall prevent the introduction and spread of injurious insect or animal pests, plant diseases, and noxious weeds 3 CCR A noxious weed does not meet standards of cleanliness and may not be produced, held or offered for sale as nursery stock. FAC It is unlawful to ship or transport any plant or any other thing into this state which is infested with any pest which has been listed, by the director, as detrimental to agriculture in this state.

8 Invasive vs. Noxious Not regulated Unless also noxious Non-native native Might be sold in trade Regulated Might be invasive Most are non- native Prohibited in trade

9 Weed Increase Over Time and Control Potential Acres Infested Eradication simple Introduction Eradication feasible Eradication unlikely, intense effort required Detection Local control and management only Public awareness typically begins Control Costs s Plant absent Scattered locations Time Numerous locations At or near biological potential

10 Problem weeds on the Gaviota Coast Geraldton carnation spurge, Euphorbia terracina Artichoke thistle, Cynara cardunculus Purple starthistle, Centaurea calcitrapa Giant reed, Arundo donax Onionweed, Asphodelus fistulosus Pampasgrass, Cortaderia selloana & Cortaderia jubata Yellow starthistle, Centaurea solstitialis Fountaingrass, Pennisetum setaceum

11 Why are these weeds a problem? Reduce plant and wildlife diversity Monocultures Reduce rangeland and habitat value Toxicity or spines - livestock and wildlife don t graze Increase maintenance costs for roads and agriculture Mowing, manual control, and spraying Increase flood and fire risk Clogging creeks and/or highly flammable

12 Geraldton carnation spurge

13 Geraldton carnation spurge

14 Geraldton carnation spurge

15 Weed Alert! Geraldton carnation spurge Highly invasive Monotypic stands Wide growth range Currently rare but potential for spread is high (EDRR target) Toxic sap Temporary blindness Dermatitis Noxious weed B rated

16 Artichoke thistle

17 Artichoke thistle

18 Artichoke thistle March 16, 2005

19 Artichoke thistle March 8, 2010

20 Purple starthistle

21 Giant reed

22 Onionweed

23 Pampasgrass

24 Yellow starthistle

25 Fountaingrass

26 For more information Agricultural Commissioner s Office David Chang, (805) Camino del Remedio, Santa Barbara CA