ENHS Nature Trails - Vol. 34, No. 4, January 2000

Nature Trails
Published by the Eugene Natural History Society
Volume Thirty-four, Number Four, April 2000

Table of Contents

Feature: This month's speaker: Pat McDowell

President's column: "The role of the ENHS in the 21st Century," by Nathan Tublitz

A n n o u n c e m e n t s
Mount Pisgah Arboretum activities SATURDAY, APRIL 22, 9am-Noon: Kalapuya Seasonal Cycles Workshop with Adrienne Schartz. Honor Earth Day 2000 by learning how our predecessors were sustained by nature all year round for thousands of years. A slideshow, cordage demonstration, and walk will be included. Fee: $10 ($7 MPA members). Pre-registration required; call (541) 747-1504. SATURDAY, APRIL 22, 1-4 pm: Wildflower Walk with David Wagner. See the Arboretum at the peak of its wildflower season - an excellent way to celebrate Earth Day 2000! Meet at the Visitor Center. Suggested donation: $3 (MPA/ENHS members free). FRI., SAT., AND SUN., APRIL 28 thru 30, 2000, 9 am - 3 pm: Spring Field Botany Workshop with Dr. Rhoda Love, retired LCC Botany Professor. Learn to identify and recognize common wildflowers of the Willamette Valley. Includes discussion of botanical terms, plant family characteristics, and scientific names. Practice "keying plants" using Flora of the Pacific Northwest by Hitchcock and Cronquist. Explore plant community ecology in at least 3 different habitats to understand the relationships between floral elements and ecological requirements. Participants provide own lunch, Flora of the Pacific Northwest book, hand-lens and field notebook. Fee: $100 ($90 MPA/NPSO members). Limited space. Registration required by April 25. Call MPA Education Program to Register: (541) 747-1504. SATURDAY, APRIL 29, 9 am-noon: Wildflower Walk with Jenny Lippert. This will also be a bird walk in conjunction with the Audubon Society. Meet at the Visitor Center. Suggested donation: $3 (MPA/LCAS members free). Bird Walks (bring binoculars) - Suggested donation : $3 (MPA members free!) All walks meet at Mt. Pisgah Arboretum Visitor Center, Buford Park, Eugene, OR. (541) 747-1504 for details. Saturday, May 6, 9-11 am with Rick Ahrens. Sunday, May 7, 8-10 am with Davey Wendt & Diane Pettey. Saturday, May 13, 8-10 am with Dan Heyerly. Saturday, May 13, 2-4 pm: Reptile & Amphibian Walk with Tom Titus. Hunt for herps with a local specialist from U. of O. Suggested donation: $3 (MPA members free!). Meet at Mt. Pisgah Arboretum Visitor Center, Buford Park, Eugene, OR. (541) 747-1504 for details. Sunday, May 14, 10 a.m., noon, & 2 p.m.: Mother's Day Tea and Wildflower Walks - a benefit for the Arboretum's Education Program. Fee: $10; $5 for mothers. Leaders: 10 a.m. - Susan Morasci; Noon: Judith Manning; 2 p.m.:Dr. Jan Gagnon (medicinal herbs + wildflowers). Refreshments will be served. Meet at Mt. Pisgah Arboretum Quonset Hut, Buford Park, Eugene, OR. (541) 747-1504 for details. Sunday, May 21, 10 a.m. - 4 p.m.: Mt. Pisgah Arboretum Wildflower Festival. Wildflower displays, plant sale, educational exhibits, guided walks, children's activities, music and food! Suggested donation: $3 ($6 per family). Location: Buford Park, Eugene, OR. Call 747-3817 for more information.	Livestock implicated in weed invasions of the arid west New scientific report finds livestock to be one of the major causes of weed invasions Portland: The Oregon Natural Desert Association (ONDA) today released a new report that finds that cattle and sheep grazing is one of the major causes of rapidly exploding populations of introduced weedy species throughout grasslands, shrublands, and woodlands west of the Rocky Mountains. The report, "Livestock Grazing and Weed Invasions in the Arid West", was written by ONDA staff ecologist and grassland expert Joy Belsky, Ph.D., and Jon Gelbard, a graduate student at the University of California at Davis. The spread of nonindigenous plant species, also referred to as alien, introduced, and exotic weeds, throughout arid and semi-arid regions of the West is one of the greatest threats facing the region's native species and ecosystems. Weeds outcompete native species, reduce biodiversity, increase fire frequency, increase soil erosion, and degrade wildlife habitat. Long-term monitoring suggests that these weed-dominated plant communities may never recover. Important alien weed species in the West are cheatgrass, medusahead, yellow starthistle, and leafy spurge. With continued grazing, these weeds form monocultures that are biological deserts. According to author Joy Belsky, "The scientific evidence is persuasive. Grasslands and shrublands grazed by cattle or sheep contain a greater density of alien weeds and fewer native plants, especially bunchgrasses, than ungrazed plant communities." Livestock contribute to weed invasions by: (1) transporting weed seeds into uninfested grass- and shrublands on their coats and in their guts; (2) grazing palatable native species while avoiding weedy species; (3) creating patches of bare, disturbed soils that act as weed seedbeds; (4) trampling fragile biological soil crusts, which otherwise inhibit weed seed germination; and (5) creating patches of nitrogen-rich soils (with urine and dung), which favor many weed species. As western landscapes are converted by livestock into weed dominated wastelands, grassland productivity declines, ranches lose their forage and real estate value, public lands lose wildlife species and picturesque wildflowers, and fires become more frequent and more destructive. The new ONDA report finds that recent management plans issued by land agencies such as Bureau of Land Management and the Forest Service consistently ignore the role livestock play in causing weed invasions. As a result, weeds continue to invade western public lands at a rate of over 5000 acres per day. "To fight weeds, land managers have to pay attention to all contributing factors, or else weed management is doomed. A weed manager who ignores livestock management is like a doctor who advises his heart disease patients to exercise more, but ignores their fried-food diets" said co-author Jon Gelbard. A copy of the report is available at www.onda.org or call 503-228-9720. Joy Belsky, Ph.D. Staff Ecologist Oregon Natural Desert Association 732 SW 3rd Avenue, Suite 407 Portland, OR 97204

A n n o u n c e m e n t s

Mount Pisgah Arboretum activities

SATURDAY, APRIL 22, 9am-Noon: Kalapuya Seasonal Cycles Workshop with Adrienne Schartz. Honor Earth Day 2000 by learning how our predecessors were sustained by nature all year round for thousands of years. A slideshow, cordage demonstration, and walk will be included. Fee: $10 ($7 MPA members). Pre-registration required; call (541) 747-1504.

SATURDAY, APRIL 22, 1-4 pm: Wildflower Walk with David Wagner. See the Arboretum at the peak of its wildflower season - an excellent way to celebrate Earth Day 2000! Meet at the Visitor Center. Suggested donation: $3 (MPA/ENHS members free).

FRI., SAT., AND SUN., APRIL 28 thru 30, 2000, 9 am - 3 pm: Spring Field Botany Workshop with Dr. Rhoda Love, retired LCC Botany Professor. Learn to identify and recognize common wildflowers of the Willamette Valley. Includes discussion of botanical terms, plant family characteristics, and scientific names. Practice "keying plants" using Flora of the Pacific Northwest by Hitchcock and Cronquist. Explore plant community ecology in at least 3 different habitats to understand the relationships between floral elements and ecological requirements. Participants provide own lunch, Flora of the Pacific Northwest book, hand-lens and field notebook. Fee: $100 ($90 MPA/NPSO members). Limited space. Registration required by April 25. Call MPA Education Program to Register: (541) 747-1504.

SATURDAY, APRIL 29, 9 am-noon: Wildflower Walk with Jenny Lippert. This will also be a bird walk in conjunction with the Audubon Society. Meet at the Visitor Center. Suggested donation: $3 (MPA/LCAS members free).

Bird Walks (bring binoculars) - Suggested donation : $3 (MPA members free!) All walks meet at Mt. Pisgah Arboretum Visitor Center, Buford Park, Eugene, OR. (541) 747-1504 for details.
Saturday, May 6, 9-11 am with Rick Ahrens.
Sunday, May 7, 8-10 am with Davey Wendt & Diane Pettey.
Saturday, May 13, 8-10 am with Dan Heyerly.

Saturday, May 13, 2-4 pm: Reptile & Amphibian Walk with Tom Titus. Hunt for herps with a local specialist from U. of O. Suggested donation: $3 (MPA members free!). Meet at Mt. Pisgah Arboretum Visitor Center, Buford Park, Eugene, OR. (541) 747-1504 for details.

Sunday, May 14, 10 a.m., noon, & 2 p.m.: Mother's Day Tea and Wildflower Walks - a benefit for the Arboretum's Education Program. Fee: $10; $5 for mothers. Leaders: 10 a.m. - Susan Morasci; Noon: Judith Manning; 2 p.m.:Dr. Jan Gagnon (medicinal herbs + wildflowers). Refreshments will be served. Meet at Mt. Pisgah Arboretum Quonset Hut, Buford Park, Eugene, OR. (541) 747-1504 for details.

Sunday, May 21, 10 a.m. - 4 p.m.: Mt. Pisgah Arboretum Wildflower Festival. Wildflower displays, plant sale, educational exhibits, guided walks, children's activities, music and food! Suggested donation: $3 ($6 per family). Location: Buford Park, Eugene, OR. Call 747-3817 for more information.

Livestock implicated in weed invasions of the arid west

New scientific report finds livestock to be one of the major causes of weed invasions

Portland: The Oregon Natural Desert Association (ONDA) today released a new report that finds that cattle and sheep grazing is one of the major causes of rapidly exploding populations of introduced weedy species throughout grasslands, shrublands, and woodlands west of the Rocky Mountains. The report, "Livestock Grazing and Weed Invasions in the Arid West", was written by ONDA staff ecologist and grassland expert Joy Belsky, Ph.D., and Jon Gelbard, a graduate student at the University of California at Davis.

The spread of nonindigenous plant species, also referred to as alien, introduced, and exotic weeds, throughout arid and semi-arid regions of the West is one of the greatest threats facing the region's native species and ecosystems. Weeds outcompete native species, reduce biodiversity, increase fire frequency, increase soil erosion, and degrade wildlife habitat. Long-term monitoring suggests that these weed-dominated plant communities may never recover.

Important alien weed species in the West are cheatgrass, medusahead, yellow starthistle, and leafy spurge. With continued grazing, these weeds form monocultures that are biological deserts.

According to author Joy Belsky, "The scientific evidence is persuasive. Grasslands and shrublands grazed by cattle or sheep contain a greater density of alien weeds and fewer native plants, especially bunchgrasses, than ungrazed plant communities." Livestock contribute to weed invasions by:

(1) transporting weed seeds into uninfested grass- and shrublands on their coats and in their guts; (2) grazing palatable native species while avoiding weedy species; (3) creating patches of bare, disturbed soils that act as weed seedbeds; (4) trampling fragile biological soil crusts, which otherwise inhibit weed seed germination; and (5) creating patches of nitrogen-rich soils (with urine and dung), which favor many weed species.

As western landscapes are converted by livestock into weed dominated wastelands, grassland productivity declines, ranches lose their forage and real estate value, public lands lose wildlife species and picturesque wildflowers, and fires become more frequent and more destructive.

The new ONDA report finds that recent management plans issued by land agencies such as Bureau of Land Management and the Forest Service consistently ignore the role livestock play in causing weed invasions. As a result, weeds continue to invade western public lands at a rate of over 5000 acres per day.

"To fight weeds, land managers have to pay attention to all contributing factors, or else weed management is doomed. A weed manager who ignores livestock management is like a doctor who advises his heart disease patients to exercise more, but ignores their fried-food diets" said co-author Jon Gelbard.

A copy of the report is available at www.onda.org or call 503-228-9720.

Joy Belsky, Ph.D.
Staff Ecologist
Oregon Natural Desert Association
732 SW 3rd Avenue, Suite 407
Portland, OR 97204

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