BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Eragrostis lehmanniana | Lehmann Lovegrass 



GENERAL BOTANICAL CHARACTERISTICS : 
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.
 


RAUNKIAER LIFE FORM : 
   Hemicryptophyte


REGENERATION PROCESSES : 
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].  


SITE CHARACTERISTICS : 
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.


SUCCESSIONAL STATUS : 
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].


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

Related categories for Species: Eragrostis lehmanniana | Lehmann Lovegrass