| | |
 |
|
| 
| ||
 |
|
|
|
 |
|
Wildlife, Animals, and Plants |
|
|||
|
BOTANICAL AND ECOLOGICAL CHARACTERISTICS
GENERAL BOTANICAL CHARACTERISTICS:Sand dropseed is a warm-season [15,123], shallow-rooted [65], drought resistant [18,26,32], perennial bunch grass [123]. The solid stemmed [26] small tufts [61] of sand dropseed reach 12 to 40 inches (30-100 cm) tall [6,15]. Sand dropseed is a polymorphic species [103,132]. Leaf blades range from 3 to 10 inches (8-25 cm) long and 8/100 to 2/10 of an inch (2-5 mm) wide [51]. The panicle is purplish to lead colored [91,98], with the inflorescence ranging 6 to 16 inches (15-40 cm) long [61,123] and 1 to 6 inches (2-15 cm) wide [123]. A sheath partially encloses the inflorescence [85]. The roots of sand dropseed are fine, 2/100 of an inch (0.5 mm) or less in diameter, stretching from a short stocky rhizome [35]. These fine roots may stretch laterally up to 10 inches (25 cm) and up to 31 inches (78 cm) down through the soil [35]. At 2 to 3 inches (5-8 cm) below the soil surface, lateral roots branch and rebranch continuously forming a dense, soil binding mat [35].
RAUNKIAER LIFE FORM [106]:Hemicryptophyte REGENERATION PROCESSES:Regeneration is accomplished by seed which sets May to August [51] and by tillering from residual plant parts [123]. A prolific seed producer [31,34,50,60,91], one panicle of sand dropseed has yielded 10,000 seeds [22]. Sand dropseed produces small seed (5,298,000 seeds/lb) [4]. During seed maturation, the upper leaf sheath partially encloses the inflorescence. As the sheath weathers away, seed is disseminated [41]. Weathering of the previous growing season's leaf sheath and dispersal of seed may continue after new growth begins [31]. Rabbits may also be involved in dissemination of seed [21,108]. Contribution of seed to the seed bank is well documented, even within sites where sand dropseed is currently missing [50,110] or low in coverage [29,101]. This large contribution to the seed bank, both within and outside of sand dropseed communities, is consistent with the small seed size and wind dispersal [34]. An evaluation in western Iowa observed a large contribution of viable seed to the seed bank of a deciduous woodland (Cornus and Ulnus spp.) downhill from a ridge top grassland [110]. The number of viable seeds produced and relative seedling vigor are extremely variable for sand dropseed [1,32,39,76,110]. An evaluation in Colorado reported excellent germination and rapid growth [32]. Other studies have found sub-optimal germination and seedling response [39,76]. Compared to other species within the Kansas mixed-grass prairie, sand dropseed produces larger numbers of seed during periods of water stress [22]. In general, seedlings are usually slow to develop [6] but are persistent and drought resistant [6,60]. Studies evaluating germination cues recognize several methods to increase germination. Pricking seeds and scarifying with coarse sand helps germination [74]. Trampling by cattle provides another form of physical scarification. Good response was seen in burned blackbrush (Coleogyne ramosissima spp.) areas aerially seeded and then trampled by cattle [67]. A warm temperature germination requirement suggests seedling emergence and survival are related to late spring environmental conditions [68]. Alternating temperatures between cold and warm gives the best germination responses. The presence of light in conjunction with alternating temperatures also increases germination percentages. For specific temperatures and alternation times please see references [112,114].In the Nebraska sandhills, the highest germination percent came from seeds within the top 2 inches (5cm) of the soil [101].
SITE CHARACTERISTICS:Sand dropseed occurs in several soil types [103,123,132] and elevations [123] with site characteristics varying according to region. Within the Nebraska sandhills, preferred sites are sandier areas [136] of dry valley bottoms and dune base slopes [47]. Clay soils [36,103], silty clay loam [36], sandy loam [34], sandy alluvial soils [71], and gravelly soils [31,123,130] are also inhabited. In general, open [102] and disturbed areas with permeable, sandy soils [69,70,102] are preferred. Dry sandy ridges and plains are preferred in south-central New Mexico [26]. In southern Ontario, dry prairies with coarse sand and sandy loam are preferred [41]. Although sand dropseed prefers well-drained and permeable soils, populations are not restricted. Areas subjected to seasonal flooding are also inhabited by sand dropseed. Sand dropseed occurs under cottonwoods (Populus spp.) within intermittent streambeds [3] and upland areas of playa lakes [63]. Sand dropseed is also found within cottonwood communities of the South Platte and Arkansas river floodplains. [86]. Sand dropseed does not require high amounts of soil moisture. Populations are widespread in the Great Basin where summer rains are inconsistent from year to year and moderate in long-term averages [30]. Some states and relative elevational ranges where sand dropseed occurs:Arizona 200 to 7000 feet (60-2100 m)[70] California 100 to 900 feet (30-270 m) Colorado 3500 to 8000 feet (1100-2400 m) Utah up to 7,000 feet [130]
SUCCESSIONAL STATUS:Sand dropseed is a colonizer of drought disturbed and previously cultivated lands. Invasion and establishment upon previously abandoned cultivated lands in the southern plains has been observed [132]. Within semi-arid mixed prairie landscapes, sand dropseed is one of the 1st to colonize denuded sandy to silty soil rangelands [60]. Sand dropseed was the principle grass within a field 14 years out of cultivation in Colorado [32]. Sand dropseed is also good at colonizing open spaces associated with heavy grazing [95]. In Texas, sand dropseed is a common invader of short-grass and mid-height grass mesquite/buffalo grass (Buchloe dactyloides) communities [11].
SEASONAL DEVELOPMENT:Phenology of sand dropseed corresponds to water availability. Sand dropseed has almost immediate response to available soil moisture [26]. In general, sand dropseed starts growth late spring [24,103,130] with seed maturing late summer to early fall [22,123]. This is slightly different in arid habitats. In the Chihuahuan desert of New Mexico, flowering was observed to begin in August with fruiting occurring in October [78]. Development occurs rapidly during periods of abundant moisture [26] with induced dormancy during periods of drought between rains [26]. Large amounts of late summer precipitation provide for the possibility of 2 or more reproductive phases [15].
Related categories for Sporobolus cryptandrus | Sand Dropseed |
 |
 | |
| |
| |
| Content on this web site is provided for informational purposes only. We accept no responsibility for any loss, injury or inconvenience sustained by any person resulting from information published on this site. We encourage you to verify any critical information with the relevant authorities. | |
| |
|
About Us | Contact Us | Terms of Use | Privacy | Links Directory |
| 1Up Info All Rights reserved. Site best viewed in 800 x 600 resolution. |
