Interdisciplinary topics on invasive

plant control

Miriam Sachs Martínm.sachs.martin@gmail.com

I ♥ Weeds and People Master’s degree in Social Science,

Interdisciplinary at SFSU. Thesis at Pearson-Arastradero Preserve

and employment at Acterra. Experiment with one method of controlling

hemlock on the preserve GIS mapping and data review Literature analysis and program

recommendations about volunteerism

THE STUDYSection 1

Invasive Species 50,000 alien species have invaded the

US.¹ Estimated cost to US: $137 billion/year.² Second most powerful threat to

biodiversity worldwide. ² HIPPO

H = Habitat Loss and Fragmentation I = Invasive Plants P = Pollution P = Population (human overpopulation) O = Overconsumption

Hemlock biology Can grow 3-10 feet

in one year.

Allelopathy

Density – 595 plants in ½ M²

Grows in shady, moist areas.

Produces 5,000 to 38,000 seeds per plant.

Pearson-Arastradero Preserve CA floristic province –

2120 / 3500 vascular plants are endemic.³

247 ha supports 334 species.

Concerns: Invasive plants, recreation impacts.

Contiguity + urbanization = high habitat value.

Related Research Replanting

Oversowing with biologically similar natives (Simmons)4

Effective competitors (Dukes)5

Alellopathy Andrews6: Early

growth and senescing is worst.

Recommends fall/winter removal, re-sow with native grass seed

Site selection 2007 populations of Conium were GPS’d to

compare with 2001 maps. Four areas were selected for: ease of

access, over 75% hemlock coverage, relevancy to Acterra’s work, and volunteer safety.

49 ½ m² quadrats, monitor for 15 months Randomized quadrat locations and

treatments.

Plot locations

Study Design

Hand-pull and re-seed with native plants of similar biology. Elymus glaucus - Blue Wild Rye

Perennial native bunchgrass, can be found in shady areas.

Achillea millefolia –Yarrow Grows near hemlock, prolific, mid-summer seed.

Hemizonia congesta ssp. Luzulifolia - Hayfield tarweed

Late summer seed, forms dense stands.

Originally 5 treatments: Control, pull, replant grass, replant forbs, replant mix.

Results Pre-treatment Conium counts varied from

35 plants per quadrat to 700. High plot attrition. No statistically significant difference

between any of the treatments and the control. No statistically significant correlation found for

Conium maculatum regrowth and: Soil moisture Canopy % or canopy species Slope or aspect Ecotype or plant associates

0.51.01.52.02.53.03.5

TREATMENT

Control Pull Reseed

Treatment Variable

0

100

200

300

400

500

600

Plan

t Cou

nt

Control Pull Reseed

Treatment Variable

0

100

200

300

400

Plan

t Cou

nt

January, 2007Pre-treatment

March, 200815 months after treatment

Graph of results

Recommendations Larger quadrat size – entire plot area instead

of quadrats. Natural boundary, no seed rain. Live plants, not seed. Large size (G), not

plugs. Different plants – shade loving,

rhizotomatous. Baccharis douglasii – Marsh baccharis Heracleum lantanum – Cow parsnip Leymus triticoides – Wet meadow rye Rubus ursinus – CA blackberry Anything you see growing interspersed with

hemlock. Research sites AWAY from restoration areas.

MAPPINGSection 2

Observations Hemlock has

increased in quantity and spread to new areas since 2001.

Spread has primarily occurred along trails and waterways.

Photo by David Smernoff

Recommendations Mapping protocols. Focus on seed-

head clipping and other trailside control work.

Share info at interp. and volunteer events.

Signage, outreach to recreation users. Consider signs at

infestation site / trails.

Photo by Richard Bicknell

VOLUNTEERSSection 3

Background 26 % of US - 61 million people a year6

Why people volunteer (Measham and Barnett)7

Helping a cause Social interaction Improving skills Learning about the

environment General desire to care

for the environment Desire to care for a

particular place

Program planning Integrated educational

component Games, acronyms, audience

participation Skill-building

Project-specific: plant ID, clinometer, research methodology

Program-wide: Educational materials, combined interpretive focus with volunteer work days

Teamwork, meet new people Sense of place: “You are the

stewards of this land.” Biocultural diversity.

Biocultural diversity = Life + Culture + Difference

Connection between Native American cultural areas and ecological niches.8

2124 of CA’s endemic plants overlapped geographically with 14 language families and dialects of 72 endemic Native languages.9

Diverse peoples = Diverse ecologies?

Implications Cocks (2006):

Learn dynamics of various groups’ biocultural values (focus on recreation, resource use, etc.)

Use those as starting points for building additional approaches towards community based conservation.

Results and RecommendationsResults Volunteer participation

rose sharply 750 – 1350.

Participants demonstrated knowledge acquisition & satisfaction with experience.

Increased community participation builds future support base.

Recommendations Program planning -

continue satisfying Measham and Barnett’s six factors

Without essentializing individuals, integrate a biocultural approach into Stewardship work.

Acknowledgements This is a community and collaborative

success. The 2007-08 ASP team: Verna Kirkendall, Claire

Elliott, Sheri Lubin, Deanna Giuliano, and other Acterra folk provided invaluable support and assistance.

Maps are courtesy of Paulo Philippides. Cyrus Hiatt also helped with mapping and data management.

Christine Zable counted about a million hemlock plants.

Tom Cochrane provided plant ID help throughout.

The Rangers were awesome, as usual. Thank you to all the volunteers, friends, family,

colleagues, professors, fellow students, and everyone else who helped.

References 1. Pimentel, D., Zuniga, R., and Morrison, D. (2004). Update on Environmental and

Economic Costs Associated with Alien-Invasive Species in the United States. Ecological Economics, Vol. 52, pp. 278-288.

2. Wilson, Edward O. 2002. The Future of Life. Random House, New York, New York. 229 p.

3.  Conservation International (2006). California Floristic Province. Retrieved May 8, 2006 from http://www.biodiversityhotspots.org/xp/Hotspots/california_floristic/

biodiversity.xml. 4. Simmons, M. (2005). Bullying the Bullies; The Selective Control of an Exotic,

Invasive Annual (Rapistrum rugosum) by Oversowing with a Competitive Native Species.

Restoration Ecology, Vol. 13, pp. 609-615. 5. Dukes, Jeffrey. (2001). Biodiversity and Invasibility in Grassland Microcosms. Oecologia, Vol 126, pp. 563 - 568. 6. United States Department of Labor, Bureau of Labor Statistics (2008).

Volunteering in the United States, 2008. Economic news release retrieved May 21, 2009 from http://www.bls.gov/news.release/volun.nr0.htm.

7. Measham, Thomas B. and Barnett, Guy B. (2007). Environmental volunteering: motivations, modes and outcomes. Socio-economics and the environment in discussion : CSIRO working paper series; 2007-03. 30 p.

8. Kroeber (1963) cited in Maffi, Luisa, (2005). Linguistic, cultural, and biological diversity. Annual Review of Anthropology, Vol. 34, pp. 599-617.

References 9. Chung, Eugene R. (2000). Biocultural Diversity Hotspots and GIS Analysis: Alta

California as a Case Study. Abstract. Presented at the 2000 Annual Meeting of the Society for Economic Botany. Retrieved 05/25/07 from: www.econbot.org/_organization_/07_annual_meetings/meetings_by_year/2000/abstracts_2000.pdf.

10. Cocks, Michelle (2006). Biocultural Diversity: Moving Beyond the Realm of 'Indigenous' and 'Local' People. Human Ecology, Vol. 34, pp. 185 - 200.