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Common Names: birdfoot deervetch,
bird’s-foot trefoil, bloomfell, cat's clover, crowtoes,
ground honeysuckle
Native Origin: Europe
Description: A perennial,
fine-stemmed, leafy legume (pea family, Fabaceae)
that grows 6-24 inches in height. Erect stems are nearly
square, emerge from a single root crown and have many
branches that can become tangled and matted. Clover-like
leaves are pinnately compound, alternate, and consist of
three oval leaflets and two smaller leaflet-like
stipules that grow at the base of the leaf stalk.
Flowers are bright yellow, sometimes streaked with red,
½ inch long, born in flat-topped clusters of three to
six at the end of stems, and bloom from June to frost.
Clusters of slender brown to black seed pods are
cylindrical, resemble a bird’s foot, and contain 10-20
seeds that eject when mature. The deep, branched root
system has a 3-foot long taproot and secondary roots
from rhizomes. It reproduces by seed, rhizomes and above
ground runners that form fibrous mats.
Photo: Mary Ellen (Mel) Harte, Bugwood.org
Habitat: It is located in
roadsides, waste areas, fields, prairies, wildlife
openings, and open disturbed areas. It tolerates a
variety of soil types including dry, moist, hardpan or
droughty soils. It is a common lawn weed in western NY.
Distribution: This species is
reported from states shaded on Plants Database map. It
is reported invasive in CA, IL, MN, MO, OR, TN, VA, WA,
and WI.
Ecological Impacts: Bird’s-foot
trefoil creates tangled mats of dense growth that can
choke out other plants. It spreads to threaten the
diversity of native plants.
Control and Management:
• Manual- Dig up small infestations,
remove all root fragments; frequent mowing at a
height of 2" for several years helps control the
plant, but can set back native plants. Note:
Control burns are not recommended because they
increase seed germination and promote seedling
establishment
- • Chemical- It can be effectively
controlled using any of several readily available
general use herbicides such as clopyralid,
glyphosate, or triclopyr. Follow label and state
requirements.
- • Natural enemies- One fungal associate,
Erysiphe betae and seven species of
arthropods are reported to occur on Lotus
including one bug and six lepidopterans.
References:
www.forestimages.org
http://plants.usda.gov
www.nps.gov/plants/alien
Czarapata, Elizabeth J. Invasive Plants of the Upper
Midwest, An Illustrated Guide to their Identification
and Control, 2005 p. 64-65,
www.invasive.org/weeds/asian/lotus.pdf
www.npwrc.usgs.gov/resource/othrdata/plntguid/species/lotucorn.htm
www.hort.purdue.edu/newcrop/Crops/Birdsfoot_trefoil.html
Produced by the USDA Forest Service, Forest Health
Staff, Newtown Square, PA. WOW 07-10-06 Invasive Plants
website:
http://www.na.fs.fed.us/fhp/invasive_plants
Photo: Mary Ellen (Mel) Harte,
Bugwood.org |
Photo: Richard
Old, XID Services, Inc., Bugwood.org |
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Bird's-foot Trefoil Distribution - United States |
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Trends and rising threats from invasive species
Humans intentionally and unintentionally spread invasive
species. The foundations of agriculture and animal husbandry
are based on ancient habits of selectively favoring some
plant and animal species and their habitats over others for
food, fiber, and medicine (Flannery 1973). According to
Pimentel and others (1999), about 50,000 non-native species
have been introduced in the United States. Many nonnative
species have been deliberately introduced for erosion
control (kudzu), food animals and fish (brown trout),
agricultural crops (Johnson grass), and ornamental trees and
landscape plants (purple loosestrife). Some insects and
diseases have been introduced in ignorance, as was the Gypsy
Moth, or as the unintentional result of a global economy, as
with the West Nile virus and Zebra mussels (Pimental and
others 1999). Many invasive plants in the United States were
originally introduced for food, fiber or erosion control, or
as ornamentals. For example, purple loosestrife was
introduced as an ornamental in the early 19th century.
Loosestrife is present in riparian areas throughout the
continental United States and control costs are an estimated
$45 million per year. Riparian areas are extremely
valuable to native plants and animals, and the wholesale
invasion by Loosestrife poses a serious threat of eventual
extinction to numerous riparian-dependent species (Pimentel
and others 1999).
Other plant species, such as European
Cheatgrass, have almost entirely displaced
sagebrush-grassland plants and associated animals.
Cheatgrass has also seriously altered the fire regime from
an average return interval of 60-110 years to 0-3 years.
Cheatgrass is an example of the adverse impacts an
introduced species can have on the environment. Some
scientists estimate that Cheatgrass is present on 100
million acres of grassland-steppe in the western United
States. Cheatgrass forms a dense, uniform carpet that
out-competes native grasses and shrubs. It greens quickly,
dries quickly and produces a very flammable cover that often
burns completely, without allowing native plants to
reestablish. In pinyon-juniper woodlands, the combination of
Cheatgrass and fire may effectively prevent the
re-establishment of the original woodlands (Mitchell 2000). |
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Purple Loosestrife
Lythrum salicaria
© 2001 CDFA
Rana aurora draytonii
California Red-
Legged Frog
© 2002 Pierre Fidenci |
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Invasive species cost the public
approximately $137 billion per year in damage, loss, and
control (Pimentel and others, 1999). The economic losses are
significant but the ecological and cultural losses of native
flora and fauna are equally important. For example, the
bullfrog, a nonnative species in California, has almost
completely replaced the native California red-legged
frog--the famed jumping frog of Calaveras County. Another
introduced plant, the Giant Reed, eliminates native
streamside vegetation and dries up creeks that provide
habitat for four endangered species: least bell’s vireo,
southwestern willow flycatcher, California red-legged frog,
and unarmored three-spine stickleback (USDA Forest Service
2003a).
Approximately 46% of the plants and
animals federally listed as endangered species have been
negatively impacted by invasive species (Wilcove and others
1998). Introduced insects and disease have also taken their
toll on the environment. Chestnut Blight and Dutch elm
disease are two well-known examples. Gypsy moth was
intentionally introduced in the 1800s as a possible source
of silk production. As a result of these well-known pests,
the American chestnut and American elm have virtually
disappeared from the US landscape and numerous other eastern
trees are at risk from Gypsy moth (USDA Forest Service
2001).
What is the role of the Forest Service?
The Forest Service Chief has recognized the threat that
invasive species pose to forest health, the economy, and the
mission of the Forest Service. The interaction between the
invasive species threat and other significant threats needs
to be considered. For example, accidental spread of invasive
species by unregulated OHV use, the spread of invasives on
newly burned areas, and the wide swaths of some invasives
that fragment habitats are obvious interactions. The
invasive species issue is broad and impacts almost all
terrestrial and aquatic habitats nationwide.
Law and policy governing invasive species
Managing and controlling invasive species requires an
extraordinary coordination of programs, research, and
management actions at the federal, state, and local levels.
Invasive species affect all land ownerships and
jurisdictions. The U.S. Department of Agriculture alone has
six agencies involved in the control of invasive species
(Tenny 2002). The Federal Noxious Weed Act of 1974, as
amended (7 U.S.C. 2801 et. seq.), 36 C.F.R. 222.8,
Departmental Regulation 9500-10, and Forest Service Manual
2080 outline agency responsibilities for noxious weed
management. (Note: not all legally defined “noxious weeds”
are non-native invasive plants.) FSM 2080 provides guidance
to the National Forest System to address the more narrowly
defined “noxious weed management”. Forest Service
responsibilities and management direction for the control of
insects and disease are listed in the Cooperative
Forestry Assistance Act of 1978 (92 Stat. 356; 16 U.S.C.
2101) and Forest Service Manual 3400.
In 1999, Executive Order 13112 created
the National Invasive Species Council (NISC) co-chaired by
the Departments of Agriculture, Commerce and Interior. The
executive order recognized the ecological and economic
threat posed by invasive species and directed a broad
intergovernmental effort to address invasive species
problems (National Invasive Species Council 2001). An
Invasive Species Advisory Committee of non-federal
representatives was appointed by NISC to provide advice and
information to federal agencies. NISC’s Management Plan,
published in 2001, set nine goals including prevention,
early detection and rapid response, control and management,
restoration, international cooperation, research and
education (NISC, 2001).
The Forest Service is developing a
comprehensive national strategy to alleviate the impacts and
reduce the threat from exotic invaders (Forest Service
2003). Invasive species control is also addressed in the
agency’s strategic plan under “Goal 2: reduce the impacts
from invasive species” (USDA Forest Service 2003b). The
objective under this goal is to “improve the effectiveness
of treating selected invasive species on the Nation’s
forests and grasslands. |
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Invasive Species on National
Forests / Invasive Plants
The United States has about 2,000 non-native
invasive plant species, which are concentrated in
California, Florida, and Hawaii (Mitchell 2000). On
non-croplands in the midwestern states, one Forest
Service researcher estimates that 14 percent of the
plant species are non-native invasive plants. Trend
data from the 19th century to the present indicates
a significant escalation in the percentages of
non-native invasive plants in the last half of the
20th century (Mitchell 2000). An estimated 3.5
million acres of National Forest System lands are
infested with invasive weeds, according to the 2000
RPA assessment, which summarized local estimates
from individual national forests(USDA Forest Service
2001). However, local estimates vary widely, and the
agency lacks a comprehensive inventory for either
terrestrial (land) or aquatic areas infested with
invasive species. The Framework for Invasive Species
calls for expanding inventory and monitoring
activities to identify more invasive insects,
pathogens and plants (Forest Service 2003).
Some species of particular concern to Forest Service
managers are leafy spurge, knapweeds and
starthistles, saltcedar, non-indigenous thistles,
purple loosestrife, and cheatgrass in the West and
garlic mustard, kudzu, Japanese knotweed,
Tree-of-heaven, and purple loosestrife and hydrilla
in the East (Mitchell 2000).
Insect Damage and Disease
Insect damage and plant disease are natural
disturbances that are part of a healthy, functioning
ecosystem, along with fire and wind damage. However,
both native and non-native insects and diseases have
caused above normal mortality rates on forested
lands in the United States. Some 58 million acres or
8 percent of forested land are at risk for mortality
rates that exceed the norm by 25 percent or more
(USDA Forest Service 2001). High mortality rates can
accelerate the development of high fuel-loading in
fire-dependent forests, effectively remove important
ecosystem elements, and reduce private property
values. The highest profile exotic insects and
diseases include Asian Longhorn Beetle, Emerald ash
borer, Dutch elm disease, chestnut blight, white
pine blister rust, Port-Orford cedar root disease,
European gypsy moth, hemlock wooly adelgid, and
beech bark disease. Aside from the potential
economic loss from timber volume, many wildlife and
fish species are dependent on the ecosystems
affected by these invasive insects and diseases
(USDA Forest Service, 2001).
International context
Invasive species negatively affect natural
ecosystems throughout the world by out-competing
native flora and fauna for resources and growing
space. Because there are often no biological
controls on their growth, invasive species spread
quickly and negatively impact threatened and
endangered species. At least 4,500 nonnative plant,
animal, and microbe species were established in the
United States during the 19th century, and about 15
percent of these are considered harmful (Eav 1999).
Many invasive species arrive in the United States
through international trade. Therefore, the Forest
Service must work with international partners to
stem the flow of invasive species into the country,
discern and apply biological controls for
invasives that have already established and spread,
and protect island ecosystems, which are
especially vulnerable due to their high percentage
of unique species and evolutionary isolation.
--From the USDA Forest Service position paper
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