Lehmann Lovegrass

Cox and others [9] observed that Lehmann lovegrass leaves appear within
14 days after burning whether burned in spring, summer, fall, or winter.
However, it took longer for fall-burned stands to attain prefire biomass
than stands burned at other times of the year.  This was attributed to
the killing of cold-sensitive new leaves during October and November on
fall-burned sites when night time temperatures varied between 41 and 50
degrees Fahrenheit (5 and 10 deg C).  In contrast, new leaves on sites
burned in February, June, or July remained active until night time
temperatures dropped below 41 degrees Fahrenheit (5 deg C) in
mid-December.

Lehmann lovegrass

Small birds of Southwestern grasslands, such as the eastern
meadowlark and several species of sparrows, nest in stands of Lehmann
lovegrass, but it is not preferred habitat and they more frequently nest
in native grasses [3]. 

More info for the term: warm-season

Lehmann lovegrass is an introduced, warm-season, perennial bunchgrass
growing from 1.5 to 2 feet (45-61 cm) in height [16].  Its bunch habit
is somewhat open in that individuals do not form a compact crown with
numerous stembases.  Furthermore, although more or less erect, some
stems are procumbent and these often root at the nodes.  This often
results in somewhat continuous stands where individuals are difficult to
identify [30].  Lehmann lovegrass has short, involuted leaves, which are
about 0.06 inch (1.5 mm) wide and 2 to 6 inches (5-15 cm) long.
 

More info for the term: restoration

Lehmann lovegrass is native to South Africa.  It was first introduced in
the arid Southwest in the 1930's for range restoration purposes.
Between 1940 and 1980, ranchers and government land managers established
Lehmann lovegrass on more than 172,000 acres (70,000 ha) [10]. However,
because of edaphic and climatic requirements of the plant, most stands
in Texas, New Mexico, and central Arizona disappeared within 5 years of
planting [11].  In 1988, Lehmann lovegrass was considered a major plant
species on about 347,000 acres (140,000 ha), with the majority of this
acreage in southeastern Arizona [12].

More info for the terms: fire regime, seed

Plant adaptations to fire:  Lehmann lovegrass is a seed-banking species.
Following fire, soil-stored seeds germinate when moisture conditions
become favorable.  Within a few months after fire seedling establishment
is typically abundant, resulting in replacement stands even after hot
fires that kill mature plants.  Fire promotes germination because (1)
heat from the fire scarifies the hard seed coat and (2) removing the
grass canopy results in greater soil temperature fluctuations and
greater irradiance of red light, which increase germination [25,27].

Although Lehmann lovegrass often suffers high rates of mortality from
fire, surviving individuals may reproduce vegetatively by nodal
propagation.  Eighty percent of mature plants died following a November
burn on the Santa Rita Experimental Range in Arizona, but many of the
surviving plants rooted from the nodes of decumbent tillers, resulting
in 0.3 new plants per square foot (3.2/sq meter) [26].

Fire behavior:  Temperatures during an October burn, in a nearly pure
stand of Lehmann lovegrass on the Santa Rita Experimental Range, were as
follows:  (1) greater than 752 degrees Fahrenheit (400 deg C) at the
soil surface, (2) about 356 degrees Fahrenheit (180 deg C) in Lehmann
lovegrass crowns, and (3) only slightly above normal 0.8 inch (2 cm)
below the soil surface [27].

FIRE REGIMES :
Find fire regime information for the plant communities in which this
species may occur by entering the species name in the FEIS home page under
"Find FIRE REGIMES".

More info for the terms: fuel, seed, shrub

Following severe fires which kill mature plants, Lehmann lovegrass
increases its dominance in mixed stands, especially when found with
grama grasses, because it establishes from seed more easily [27].

Cable [8] suggests that Lehmann lovegrass may be a useful fuel source
for shrub control in semidesert environments because it produces about
twice as much fuel as black grama (Bouteloua eriopoda).  In southern
Arizona, mortality of velvet mesquite (Prosopis velutina) larger than 2
inches (5 cm) in basal diameter, was 4 times as high when burned in
Lehmann lovegrass stands than when burned in black grama stands.

Prescribed fall burns are not recommended for Lehmann lovegrass because
fall-burned stands take longer to recover than stands burned at other
times of the year.  Fall burning also removes a grazing resource for 200
to 245 days.  It will take 2 to 3 years for Lehmann lovegrass biomass to
reach prefire levels in southern Arizona and southwestern New Mexico
[9].

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More info for the term: hemicryptophyte

  
   Hemicryptophyte

More info for the terms: grassland, shrub

Lehmann lovegrass has persisted and spread primarily in desert shrub and
desert grassland ecosystems of southeastern Arizona at elevations
between 3,250 and 4,800 feet (1,000 and 1,460 m).  The plant has a
narrow range of climatic and edaphic requirements, growing best on sites
with sandy- to sandy loam-textured soils, and where winter temperatures
rarely drop below 32 degrees Fahrenheit (0 deg C) and summer rainfall
ranges between 6 and 8.6 inches (15 and 22 cm) [10,12].

In southeastern Arizona, Cox and others [10] observed that where summer
rainfall was between 6 and 8.6 inches (15-22 cm), Lehmann lovegrass grew
vigorously and colonized adjacent unplanted areas.  On areas where
summer rainfall was about 4 inches (10 cm), stands maintained themselves
but did not spread.  Where summer rainfall was between 2.8 and 3.3
inches established stands died.

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This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

   242  Mesquite

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This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

More info for the term: shrub

   FRES30  Desert shrub
   FRES34  Chaparral - mountain shrub
   FRES40  Desert grasslands

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This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

More info for the term: shrub

   K037  Mountain-mahogany - oak scrub
   K041  Creosotebush
   K042  Creosotebush - bursage
   K044  Creosotebush - tarbush
   K053  Grama - galleta steppe
   K058  Grama - tobosa shrubsteppe
   K059  Trans-Pecos shrub savanna

More info for the terms: cover, density, fire severity, forest, root crown, severity, wildfire

Fire effects on Lehmann lovegrass vary with fire severity.  Fires during
hot, dry months result in a high percentage of plants being killed,
while "cool" winter fires tend to kill very few plants.  For example, a
late June fire on the Santa Rita Experimental Range burned or charred
mature plants to within 0.13 to 0.75 inch (0.33-1.9 cm) of the root
crown, killing 98 percent of them.  This reduced the density of mature
plants per square foot from 2.67 before the fire to 0.04 1 month after
the fire [6].  Following a July wildfire in which "virtually all
aboveground vegetation was completely burned away", lovegrass (E.
lehmanniana and E. curvula) cover decreased dramatically.  One month
after this fire, lovegrass canopy cover was about 18 percent on burned
plots and 68 percent on nearby unburned plots [3].  Conversely, few
plants are killed by "cool" winter fires.  On the Tonto National Forest,
only 4.7 percent of Lehmann lovegrass plants died within 1 year of a
February fire.  Lehmann lovegrass mortality on nearby unburned areas was
1.6 percent [23].

More info for the term: grassland

Lehmann lovegrass's greatest forage value for cattle is its ability to
produce more green herbage in the winter and early spring than native
grasses.  At this time of the year it is readily grazed [7,16].

In southeastern Arizona, the Hispid cotton rat and the Botteri's sparrow
were found to be more abundant in stands of African lovegrasses (E.
lehmanniana and E. curvula) than in native grasslands.  This is
apparently because the exotic grasses mimic native grassland habitats
prefered by these wildlife species.  However, other desert grassland
birds and rodents were less abundant in stands of the exotic lovegrasses
[4].

More info for the term: graminoid

Graminoid

More info for the term: seed

Establishment:  Lehmann lovegrass is fairly easy to establish on adapted
sites.  Most cultivars are adapted for semiarid environments below 4,500
feet (1,372 m) in elevation which receive at least 10 to 12 inches
(25-30 cm) of annual precipitation [28].  The best time for planting in
Arizona is just prior to summer rains.  The light-sensitive seeds should
be shallowly buried in sand, loamy sand, or sandy loam soils only.
Seedlings generally do not emerge from seed planted on silt loam, loam,
or clay loam soils regardless of planting depth [10].  Details for
drilling or broadcasting Lehmann lovegrass seed have been outlined [1].
Planted areas should not be grazed for 2 years to allow the new
seedlings to become well established [16].

Concern:  People interested in maintaining native grasslands are
concerned about Lehmann lovegrass's aggressive, spreading habit, and the
displacement of native grasses.  Winn [33] suggested that where control
is warranted, Lehmann lovegrass may be killed with herbicide
applications, followed by seeding of native species.

More info for the terms: fresh, warm-season

Lehmann lovegrass's nutritional importance to livestock is greatest in
the winter when its crude protein content is higher than that of many
native warm-season grasses [30].

The National Academy of Sciences [21] lists fresh, mature, aerial
portions of Lehmann lovegrass as having the following crude and
digestible protein contents:

        protein (N x 6.25) = 6.7 %
        digestible protein for cattle = 3.6 %
        digestible protein for goats = 2.8 %
        digestible protein for horses = 3.2 %
        digestible protein for rabbits = 3.8 %
        digestible protein for sheep = 3.2 %

     AZ  HI  NM  OK  TX  UT  MEXICO

The palatability of Lehmann lovegrass for cattle is low during the
summer and it is generally lightly grazed at that time [12,16].  Cattle
make greater use of this grass during fall, winter, and spring because
the foliage remains green longer than most native grasses [12,30].

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More info for the term: seed

Seed of Lehmann lovegrass matures earlier than seed of native perennial
grasses [7].

More info for the terms: density, grassland

Lehmann lovegrass generally recovers relatively quickly following fire
because of abundant seedling establishment.  For example, following a
late June fire on the Santa Rita Experimental Range in which 98 percent
of mature Lehmann lovegrass plants were killed, large numbers of
seedlings became established following summer rains.  By September 10,
the density of these new plants was 6 times greater than the original
stand [6].

Within 1 year Lehmann lovegrass plant density usually equals or exceeds
prefire levels [20,22,23], but it may take 2 or 3 years for new stands
to reach prefire biomass [3,9]. This fire response was documented in an
extensive of body of research on fire effects in semidesert grassland, oak
savanna, and Madrean oak woodlands of southeastern Arizona. See the Research Project Summary of this work for more information on burning
conditions, fires, and fire effects on more than 100 species of plants,
birds, small mammals, and grasshoppers.

More info for the term: ground residual colonizer

   Ground residual colonizer (onsite, initial community)

More info for the terms: fresh, herbaceous, natural, seed

Lehmann lovegrass is a good seed producer.  The seeds are small, with
4.2 to 6.5 million per pound (9.2-14.3 million/kg) [1,32].  Nearly all
fresh seeds are dormant, requiring at least 6 to 9 months of
afterripening.  In the laboratory, dry heat treatments of 158 degrees
Fahrenheit (70 deg C) scarifies the seedcoat and increases the rate of
inbibition [15].  Under natural conditions, seed on the ground may be
scarified by fire or by high summertime seedbed temperatures [27].  Most
seeds require exposure to red light to germinate; thus little
germination occurs when seeds are deeply buried in soil or are under a
dense herbaceous canopy.  In southeastern Arizona, high seedling
emergence typically occurs following summer rains on sites where the
canopy has been removed such as by burning, mowing, or grazing [25].

Vegetative regeneration:  Lehmann lovegrass is described as weakly
stoloniferous.  Stems that come in contact with the ground may root at
the nodes [30]. 

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This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):

    7  Lower Basin and Range
   12  Colorado Plateau
   13  Rocky Mountain Piedmont
   14  Great Plains

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More info for the term: seed

Obligate Initial Community Species

Lehmann lovegrass reseeds itself quickly after disturbance.  It is very
competitive, and where adapted, tends to replace native grasses over a
period of years.  Lehmann lovegrass has replaced Arizona cottontop
(Trichachne californica), threeawn grasses (Aristida spp.), and grama
grasses (Bouteloua spp.) over much of the Santa Rita Experimental Range
in Arizona [7].

Lehmann lovegrass's ability to replace native grass species is
attributed to:  (1) its low palatability during summer, which results in
cattle selectively grazing native grasses during the active growth
period and thus reducing their vigor; (2) its ability to produce seed
stalks early in the summer, which allows it to maintain itself when it
is grazed; and (3) its ability to establish new stands from seed after
disturbance [7,12].

The currently accepted scientific name of Lehmann lovegrass is
Eragrostis lehmanniana Nees [31]. There are no recognized varieties
or subspecies.

More info for the terms: restoration, seed

Lehmann lovegrass has been widely used for roadside stabilization and
range restoration in the Chihuahuan and Sonoran deserts [30].  The
Highway Division of the Arizona Department of Transportation uses
Lehmann lovegrass in seed mixes with other grasses to minimize erosion
and sediment damage to highways during construction [5].  Several
cultivars are available [28]. 

Perennials, Terrestrial, not aquatic, Stems nodes swollen or brittle, Stems erect or ascending, Stems geniculate, decumbent, or lax, sometimes rooting at nodes, Stems caespitose, tufted, or clustered, Stems terete, round in cross section, or polygonal, Stem internodes solid or spongy, Stem internodes hollow, Stems with inflorescence less than 1 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly basal, below middle of stem, Leaves mostly cauline, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smooth, glabrous, Leaf sheath hairy, hispid or prickly, Leaf sheath hairy at summit, throat, or collar, Leaf sheath and blade differentiated, Leaf blades linear, Leaf blades very narrow or filiform, less than 2 mm wide, Leaf blades 2-10 mm wide, Leaf blades mostly flat, Leaf blade margins folded, involute, or conduplicate, Leaf blades mostly glabrous, Ligule present, Ligule a fringe of hairs, Inflorescence terminal, Inflorescence an open panicle, openly paniculate, branches spreading, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Inflorescence branches more than 10 to numerous, Flowers bisexual, Spikelets pedicellate, Spikelets laterally compressed, Spikelet less than 3 mm wide, Spikelets with 3-7 florets, Spikelets with 8-40 florets, Spikelets solitary at rachis nodes, Spikelets all alike and fertille, Spikelets bisexual, Spikelets disarticulating above the glumes, glumes persistent, Spikelets disarticulating beneath or betwe en the florets, Rachilla or pedicel glabrous, Glumes present, empty bracts, Glumes 2 clearly present, Glumes equal or subequal, Glumes equal to or longer than adjacent lemma, Glumes 1 nerved, Lemmas thin, chartaceous, hyaline, cartilaginous, or membranous, Lemma similar in texture to glumes, Lemma 3 nerved, Lemma glabrous, Lemma apex truncate, rounded, or obtuse, Lemma awnless, Lemma margins thin, lying flat, Lemma straight, Palea present, well developed, Palea membranous, hyaline, Palea shorter than lemma, Palea 2 nerved or 2 keeled, Palea keels winged, scabrous, or ciliate, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis, Caryopsis ellipsoid, longitudinally grooved, hilum long-linear.

Eragrostis lehmanniana is a species of grass known by the common name Lehmann lovegrass. It is native to southern Africa. It is present elsewhere as an introduced species. It is well known as an invasive weed in some areas, such as Arizona in the United States.

This grass produces loose, open clumps of stems up to 61 to 80 centimetres (2.00 to 2.62 ft) long, with some stems growing erect and some lying across the ground and rooting where nodes come in contact with the substrate. The leaves are up to 15 centimetres (5.9 in) long. The inflorescence is a panicle up to 18 centimetres (7.1 in) long by 8 centimetres (3.1 in) wide, with branches appressed to the stems or held out at an angle. The spikelets are up to 1.4 cm (0.55 in) long and contain up to 14 flowers each. The grass may spread via stolons.

In its native African range this grass is common in several habitat types such as Acacia woodland and Kalahari grasslands and savanna. It has been introduced to North and South America. In 1930 the grass was introduced to Arizona in the United States to replace the native grasses that had been severely overgrazed by livestock. In the 1940s the grass was spreading and could be found growing in areas where it had not been planted. By 1980 the grass had been sown on over 100,000 acres but it failed to take hold in many regions, such as parts of Texas and New Mexico. In the desert grasslands and shrublands of southeastern Arizona, however, it did well, growing best in areas with sandy soils, rare freezes, and summer rainfall totals of about 15 to 22 cm (5.9 to 8.7 in). Much beyond these parameters it does not spread or fails to survive. In 1988 it was a major species on 347,000 acres of Arizona desert. In parts of the region, the native ecosystem has been replaced by velvet mesquite woodland with an understory dominated by Lehmann lovegrass. This species sometimes hybridizes with Eragrostis curvula ("weeping lovegrass").

The grass produces large monotypic stands that crowd out native grasses and reduce plant and animal diversity. It forms a soil seed bank that can withstand long dry periods, giving it an advantage over some native grasses. It has been shown to have a negative impact on other types of plants, such as Agave palmeri, a key component in the local ecosystem.