BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Ziziphus obtusifolia | Lotebush 



GENERAL BOTANICAL CHARACTERISTICS : 
Lotebush is a native, deciduous medium-sized shrub.  It is densely
branched and leafy.  It generally grows up to 6 feet (2 m) tall but can
reach heights of 13 feet (4 m) [21,36,42].  The branches are light gray,
covered with a waxy bloom, and have thorn-tipped branchlets.  The fruit
is a drupe with one stone [36].


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Sexual reproduction:  Lotebush reproduces by seed.  There is apparently
no innate dormancy of seed or seed-coat inhibition; Vora [51] reported a
mean emergence of 95 percent from fresh, depulped seed, and concluded
that no pretreatment is necessary for germination.  Seeds are dispersed
by birds and small mammals [50].

Asexual reproduction: Top-killed lotebush will sprout from the root
crown or, if that is removed, from the roots [19,42].


SITE CHARACTERISTICS : 
Lotebush is common on dry plains, mesas, and slopes [24].  Lotebush
occurs on limestone- and igneous-rock-derived substrates in highly
eroded areas, and on rocky prairie hillsides [21,36].  It is tolerant of
xeric conditions but can also be found on more mesic soils, such as
those immediately surrounding a desert oasis [5].  Historically,
lotebush was probably restricted to dissected uplands and rocky places
along with its woody associates.  In the past 50 to 300 years there has
been an increase in the density of woody species (including lotebush) on
grasslands [3,4,7,56].  Lotebush tends to occur in aggregated stands in
low densities [42].  In Arizona and in Trans-Pecos Texas, lotebush is
found from 1,000 to 5,500 feet (300-1,700 m) elevation [24,36].

In the Chihuahuan Desert, lotebush is associated with creosotebush
(Larrea tridentata), guayacan (Guaiacum angustifolium), lechuguilla
(Agave lechuguilla), Texas sotol (Dasylirion texanum), and Texas
persimmon (Diospyros texana).  Associated grasses in this region include
chino grama (Bouteloua ramosa), red grama (B. trifida), black grama (B.
eriopoda), sideoats grama (B. curtipendula), threeawn (Aristida spp.),
and tridens (Tridens spp.) [36].  In Saltillo, Mexico, lotebush occurs
in grassland-shrub communities with yucca (Yucca rigida) and chino grama
(B. breviseta) [30].


SUCCESSIONAL STATUS : 
Facultative Seral Species

In a study of the mechanisms by which woody species are encroaching on
Texas grasslands, Archer [3,4] found that the original colonizer of
grass swards is usually honey mesquite.  A combination of factors
appears to be responsible for the increased establishment of honey
mesquite and associated species in grasslands:  grazing and increased
dispersal of mesquite seeds by livestock, fire suppression, and possible
climatic changes [4].  Honey mesquite creates conditions for the
establishment of other woody species, either by altering soil and
moisture conditions, or simply by virtue of the fact that birds choose
to roost in it and disperse seeds of other species around its base.
Lotebush colonizes mesquite clusters around 35 to 46 years after the
mesquite is established [3].

Pinchot juniper appears to facilitate lotebush establishment on high
plains sites with shallow clay loam soils.  On these sites lotebush is
positively associated with large Pinchot juniper trees.  On Rolling
Plains sites with deeper clay loam soils, there is no such association.
Whether the association is caused by birds dispersing seeds while
roosting in the tree, or by juniper alteration of microhabitat to be
more favorable for germination of lotebush was not determined by the
study [35].  Lotebush in turn reduces Pinchot juniper growth rates
during October and November, though its zone of influence is relatively
small [34].


SEASONAL DEVELOPMENT : 
In the Rio Grande Valley, lotebush abcisses leaves as early as November,
loses most or all leaves by mid-December, and new growth is evident by
early February [52].  Lotebush flowers in April and May in the Rio
Grande Valley, and as late as July farther north [21,52].  Fruit ripens
by June in the Rio Grande Valley [52].

Germination of seeds probably takes place in summer or fall or as soon
as moisture conditions permit [51].

Related categories for Species: Ziziphus obtusifolia | Lotebush