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Photo: Anne Stine
Wildflowers
on the Range
Presented by Anne Stine
The Xerces Society for
Invertebrate Conservation
What is the Xerces Society?
Since 1971, the Xerces Society has worked to
protect wildlife through the conservation of
invertebrates and their habitat.
Major Programs:
• Pollinator conservation
• Endangered species
• Aquatic invertebrates
Xerces blue butterfly (Glaucopsyche xerces), the first U.S.
butterfly to go extinct due to human activities
Photo: World Wildlife Fund
Objectives:
• Use grazing to increase milkweed and nectar
resources for monarchs and other pollinators
• Other mgmt. to consider: survival of immature
stages, overwintering habitat…
No milkweed, no monarchs.
Photo: Anne Stine
Presentation Outline
1. Grazing and
grassland diversity
2. Grazing and
milkweeds
3. Further Resources
Photo: Anne Stine
Why grazing and
biodiversity?
• Production + semi-natural systems
• Often compatible with grassland
restoration &
• 770 million acres rangeland US
Photo: Anne Stine
Grazing and
biodiversity
• Grassland diversity comes from forbs
(=broadleaf plants, wildflowers)
• 40-60 spp. grasses- ~80% biomass
• 300+ spp. forbs- ~20% biomass
http://www.nps.gov/tapr/learn/nature/a-complex-prairie-ecosystem.htm
Photo: Anne Stine
Grasslands require periodic
disturbance to control woody
encroachment and maintain
plant diversity
Photo: Anne Stine
Lyons, R. K., Forbes, T. D. A., & Machen, R. V. (1999). What Range
Herbivores Eat--and Why. Texas A & M Extension.
Photo: Anne Stine
NOT ALL LIVESTOCK
WILL BOOST FORBS
Lyons, R. K., Forbes, T. D. A., & Machen, R. V. (1999). What Range
Herbivores Eat--and Why. Texas A & M Extension.
Photo: Anne Stine
http://www.fs.fed.us/ccrc/topics/grasslands/
Figure 1: Estimated distribution of major grasslands of
the Contiguous U.S before Euro-American Settlement.
Cingolani, Ana M., Imanuel Noy-Meir, and Sandra Díaz. "Grazing effects on rangeland diversity:
a synthesis of contemporary models." Ecological Applications 15.2 (2005): 757-773.
Photo: Anne Stine
http://www.fs.fed.us/ccrc/topics/grasslands/
GRAZING DOES NOT FIT
EVERY LANDSCAPE
Figure 1: Estimated distribution of major grasslands of
the Contiguous U.S before Euro-American Settlement.
Cingolani, Ana M., Imanuel Noy-Meir, and Sandra Díaz. "Grazing effects on rangeland diversity:
a synthesis of contemporary models." Ecological Applications 15.2 (2005): 757-773.
Photo: Anne Stine
Managing grazing lands for pollinators
Photo: USDA-NRCS/Irv Cole
In the right landscape…
•Moderate grazing can increase forb
diversity
•Diversity of range plants allows individual
animals to select their optimum diet
•Balance stocking rate and schedule rest
Cingolani, Ana M., Imanuel Noy-Meir, and Sandra Díaz. "Grazing effects on rangeland diversity:
a synthesis of contemporary models." Ecological Applications 15.2 (2005): 757-773.
Do not try to overcome natural
grazing preferences of cattle.
Overgrazing….
Photos: Sarina Jepsen
Idea: cattle preferentially select grasses,
forbs gain competitive advantage.
Under-grazing…
Photos: Anne Stine
For optimal management, the
correct combination of timing,
intensity, duration must be
found.
Just right.
Photos: Anne Stine
MILKWEEDS AND GRAZING
Photos: Anne Stine
In general, milkweeds are…
• A perennial native wildflower
that thrives on light-tomoderate disturbance.
• More toxic species found in the
south
Milkweed Toxicity and Grazing
• Most livestock do not consume milkweed on grazing
lands at sustainable stocking rates
• Consumption of ~1% of bodyweight necessary for
morbidity
• Caution: sheep will sometimes poison themselves
• Caution: milkweed becomes more palatable when
cured as hay
Photo: Brianna Borders
Photo: Anne Stine
Milkweed response to grazing
• Grazing increases milkweed abundance and vigor
by removing thatch
• Milkweeds often found on grazing lands (e.g. A.
asperula and A. syriaca)
• …But not so much in heavily sprayed or
overgrazed pastures (see: Canada thistle control)
While cattle do not consume the leaves…
• Some flowers of milkweeds are grazed preferentially
(less toxic species-- A. syriaca and A. speciosa) or
occasionally (A. viridis)
• Other flowers (A. verticillata, A. arenaria, A.
viridiflora) are avoided by cattle entirely
Photo: Anne Stine
While cattle do not consume the leaves…
• Some flowers of milkweeds are grazed preferentially
(less toxic species-- A. syriaca and A. speciosa) or
occasionally (A. viridis)
• Other flowers (A. verticillata, A. arenaria, A.
viridiflora) are avoided by cattle entirely
One solution: rest pasture periodically or
fence cattle out during bloom period
Photo: Anne Stine
Photo: Anne Stine
Other compatible practices
•
•
•
•
Prescribed fire
Mowing/Brush Mgmt.
Spot spraying
Over-seeding
Further Resources
Special Issue:
Pollinators in
Rangelands
Volume 33, Issue 3
Further Resources
Special Issue:
Pollinators in
Rangelands
Volume 33, Issue 3
Coming Soon! Technical Note
Any questions?
Anne Stine
[email protected]
(817) 509-3629
Photo: Anne Stine
The preceding presentation was delivered at the
2015 National Native Seed
Conference
Santa Fe, New Mexico April 13-16, 2015
This and additional presentations available at
http://nativeseed.info