Shortgrass Prairie - Code: Ne7A

Shortgrass prairie is a stark, low grassland occurring in the w. Great Plains in the arid rain shadow of the Rocky Mountains in the c. United States and sc. Canada. This habitat is dominated by low-growing grasses and a high diversity but low density of forbs; woody vegetation makes up less than 1% of the landscape. The Great Plains shortgrass prairies experience cool winters and warm summers, with minimum temperatures ranging from 5°F (⎻15°C) in the north to 39°F (4°C) in the south, and maximum temperatures ranging from 74°F (23°C) in the north to 100°F (37°C) in the south. Much of the annual precipitation occurs during the spring and summer months, generally falling during a small number of intense events. The average rainfall for the region is 15 in. (380mm), with amounts generally increasing in the southern and eastern parts of the range. Growth of grasses is slow due to limited rainfall, and regrowth typically takes two to three years. 
The shortgrass prairie is dominated by two low-growing warm season grasses: Blue Grama (Bouteloua gracilis) and Buffalograss (Bouteloua dactyloides). These two species make up the vast majority of the landcover, while a variety of forbs, succulents, and dwarf shrubs provide the majority of plant diversity in this habitat. Common shrubs and forbs include yuccas (Yucca spp.), pricklypears (Opuntia spp.), Prairie Zinnia (Zinnia grandiflora), Scarlet Globemallow (Sphaeralcea coccinea), Plains Blackfoot (Melampodium leucanthum), Slimflower Scurfpea (Psoralidium tenuiflorum), and Skunkbrush (Rhus aromatica). Honey Mesquite (Prosopis glandularis) is a common invasive shrub, this and Tree Cholla (Cylindropuntia imbricata) are generally signs of overgrazing.  In the wetter eastern sections of the shortgrass prairie, taller graminoids like Side-oats Grama (Bouteloua curtipendula) and Little Bluestem (Schizachyrium scoparium) can be found, though Blue Grama and Buffalograss still dominate. With the exception of a few plants, such as yuccas, the vast majority of vegetative ground cover reaches a maximum height of 10 in. (25cm) and rarely exceeds 5 in. (13cm). On sandy soils in the southern shortgrass prairie, this habitat is found mixed with large areas of low Shinnery Oak (Quercus harvardii) shrub and exposed dune. 
Variations in habitat structure and habitat maintenance are largely attributed to precipitation and grazing. Frequent droughts mean there is wide variation in the productivity and height of vegetation from year to year. Historically, this area was grazed by large herds of migratory herbivores, with American Bison being especially critical to the structure and annual maintenance of the shortgrass prairie. Along the habitat’s southern border, changes in grazing and fire regimes have led to rapid incursion from Honey Mesquite and loss of shortgrass prairie. Unsuccessful cultivation efforts leading up to the Dust Bowl agricultural disaster of the 1930s also leave large scars on the landscape.