Prairie type may be midgrass or shortgrass dependent upon soil type, moisture availability and grazing pressure.    From Wordnik.com.  [Ecoregions of Texas (EPA)] Reference

Cover types include shortgrass prairie, some midgrass prairie, scattered juniper savanna, and juniper woodland on hills.    From Wordnik.com.  [Ecoregions of New Mexico (EPA)] Reference

They are most abundant on the rolling, wide-open terrain of shortgrass or midgrass prairies, typical of many parts of Ecoregion 26.    From Wordnik.com.  [Ecoregions of New Mexico (EPA)] Reference

The Central New Mexico Plains are slightly drier than Ecoregion 26n to the east, with more shortgrass steppe and less midgrass prairie.    From Wordnik.com.  [Ecoregions of New Mexico (EPA)] Reference

The shrub and midgrass prairie vegetation includes juniper, sand sagebrush, skunkbush sumac, and yucca, along with sideoats grama and little bluestem.    From Wordnik.com.  [Ecoregions of Texas (EPA)] Reference

The proximity to runoff and moisture from the Front Range and the more loamy, gravelly, and deeper soils are able to support more tallgrass and midgrass species than neighboring ecoregions.    From Wordnik.com.  [Ecoregions of Colorado (EPA)] Reference

The potential natural vegetation in this region is grama-buffalo grass with some mesquite-buffalo grass in the southeast and shinnery (midgrass prairie with open low and shrubs) along the Canadian River.    From Wordnik.com.  [Ecoregions of the United States-Level III (EPA)] Reference

Sandy soils, formed from eolian deposits, supported a sandsage prairie natural vegetation type, different from the shortgrass and midgrass prairie of other neighboring level IV ecoregions in the High Plains (25).    From Wordnik.com.  [Ecoregions of Colorado (EPA)] Reference

They only ventured into the midgrass and tallgrass regions of the steppes in search of new growth, usually in spring when all the lands were rich with fresh grass and herbs-which was also the only time of the year when their bones and horns grew.    From Wordnik.com.  [The Plains of Passage]

The potential natural vegetation in this region is grama-buffalograss with some mesquite-buffalograss in the southeast, juniper-scrub oakmidgrass savanna on escarpment bluffs, and shinnery (midgrass prairie with low oak brush) along parts of the Canadian River.    From Wordnik.com.  [Ecoregions of Texas (EPA)] Reference

Now if by "healthy ecosystem" you mean a system in which fire and rotational grazing is practiced constantly then yes, it does tend to be somewhat controlled, but that's extremely labor-intensive work and trust me, an eastern redcedar will sprout in a beautiful, healthy pristine patch of short or midgrass prairie just as quickly as it will an eroded gully.    From Wordnik.com.  [Kill Some Trees On Earth Day] Reference

The shrub and midgrass prairie vegetation includes one-seed juniper, sand sagebrush, skunkbush sumac, and yucca, along with sideoats grama, little bluestem, western wheatgrass, blue grama, buffalograss, galleta, and alkali sacaton.    From Wordnik.com.  [Ecoregions of New Mexico (EPA)] Reference