Sandy Low P.Z .14-17

Description

Interpretations are primarily based on the Sand Bluestem/Prairie Sandreed Plant Community (this is also considered climax). The site evolved with grazing by large herbivores and is well suited for grazing by domestic livestock. This plant community is found on areas that are properly managed. The potential vegetation is about 80 percent grasses or grass-like plants, 10 percent forbs, and 10 percent shrubs. Mid and tall warm-season grasses dominate the plant community. Principal grasses are prairie sandreed and sand bluestem. The cool season grasses, needleandthread and western wheatgrass, are important. Grama grasses and sedges occur as an understory. Forbs and shrubs are not abundant.

The diversity in plant species allows for high drought tolerance. This is a healthy and sustainable plant community (site/soil stability, watershed function, and biologic integrity).

The following growth curve shows the estimated monthly percentages of total annual growth of the dominant species expected during a normal year:

Growth curve number: NE6534
Growth curve name: Nebraska/South Dakota Sandhills, Native Grasslands
Growth curve description: Warm-season dominant, cool-season subdominant, mid & tall grasses.

Transitional pathways and/or community pathways leading to other plant communities are as follows:

Continuous season-long grazing will convert this plant community to the Prairie Sandreed/Blue Grama/Needleandthread Plant Community.

Non-use and no fire will convert this plant community to the Excessive Litter Plant Community.

Submodel

Description

This plant community developed under continuous season-long grazing. It is made up of a mixture of warm and cool season grasses. The potential vegetation is about 80% grasses or grass-like plants, 10 percent forbs, and 10 percent shrubs. The dominant grasses include prairie sandreed, blue grama, and needleandthread. Other grasses include sand bluestem, switchgrass, and sand dropseed. Dominant forbs include spiderwort, Cumin (western) ragweed, and scurfpeas. Dominant shrubs include prairie (fringed) sagewort and cactus. Compared to the Sand Bluestem/Prairie Sandreed Plant Community, sand bluestem, little bluestem, and switchgrass have decreased. Blue grama, needleandthread, and sand dropseed have increased. Plant diversity is high.

This plant community is not resistant to change. It is resilient due to the high plant diversity. Soil erosion is low. The water cycle is functioning, infiltration is high and runoff is low.

The following growth curve shows the estimated monthly percentages of total annual growth of the dominant species expected during a normal year:

Growth curve number: NE6534
Growth curve name: Nebraska/South Dakota Sandhills, Native Grasslands
Growth curve description: Warm-season dominant, cool-season subdominant, mid & tall grasses.

Transitional pathways and/or community pathways leading to other plant communities are as follows:

With heavy continuous season-long grazing, this plant community will move toward the Blue Grama/Sand Dropseed/Western Ragweed Plant Community. Forage production, species diversity and ground cover will decrease.

With prescribed grazing, this plant community will move toward the Sand Bluestem/Prairie Sandreed Plant Community.

Non-use and no fire will convert this plant community to the Excessive Litter Plant Community.

Submodel

Description

This plant community develops under continuous season-long grazing for long periods of time. It is made up of short, grazing tolerant, warm season grasses and forbs. The potential vegetation is about 75 percent grasses or grass-like plants, 15 percent forbs, and 10 percent shrubs. The dominant grasses include blue grama and sand dropseed. Needleandthread, sedges, and western wheatgrass are also found. Dominant forbs include Cumin (western ragweed), annual eriogonum, and green sagewort. Dominant shrubs include fringed sagewort and cactus. Compared to the Sand Bluestem/Prairie Sandreed Plant Community, sand bluestem, prairie sandreed and switchgrass have decreased. Blue grama, western wheatgrass, and Cumin (western) ragweed have increased. Plant diversity is low.

This plant community is fairly resistant to change. If disturbed, it is not resilient due to the low species diversity. Soil erosion is low. The water cycle is reduced because of the lack of surface litter. Infiltration is moderate due to soil texture, which also reduces runoff.

The following growth curve shows the estimated monthly percentages of total annual growth of the dominant species expected during a normal year:

Growth curve number: NE6535
Growth curve name: Nebraska/South Dakota Sandhills, Grama
Growth curve description: Warm-season dominant, short grass.

Transitional pathways and/or community pathways leading to other plant communities are as follows:

Prescribed grazing will shift this plant community toward the Prairie Sandreed/Blue Grama/Needleandthread Plant Community.

Submodel

Description

This plant community developed under many years of no grazing or fire to disturb the vegetation. Plant litter accumulates rapidly as this community first develops. Eventually, litter levels become high enough that plants are crowded out and bare ground areas develop. These bare ground areas are commonly filled by annual grasses and forbs. Typically bunchgrasses develop dead centers and rhizomatous grasses form small colonies because of a lack of tiller stimulation. The potential vegetation is about 85 percent grasses or grass-like plants, 10 percent forbs, and 5 percent shrubs. Dominant grasses include prairie sandreed, sand bluestem, and needleandthread. Other grasses include switchgrass and sand dropseed. Dominant forbs include annual sunflower and ten-petal blazingstar (mentzelia). Dominant shrubs include cactus and prairie(fringed) sagewort. Compared to the Sand Bluestem/Prairie Sandreed Plant Community, sand bluestem, prairie sandreed, and perennial forbs have decreased, while needleandthread, sedges, and annual forbs have increased.

This plant community will change rapidly if plant manipulation is allowed to occur (grazing by domestic livestock or possibly periodic fire). If the intensity and duration of the disturbance is not great enough, it will return to this plant community somewhat easily. Soil erosion is low when the surface litter is high, but then increases as the litter disappears. The water cycle is functioning. Infiltration is high and runoff is low.

The following growth curve shows the estimated monthly percentages of total annual growth of the dominant species expected during a normal year:

Growth curve number: NE6536
Growth curve name: Nebraska/South Dakota Sandhills, Native Grasslands, Non-Use
Growth curve description: Warm-season dominant, cool-season subdominant, excessive litter.

Transitional pathways and/or community pathways leading to other plant communities are as follows:

Prescribed grazing or prescribed grazing with fire will convert the plant community to the Sand Bluestem/Prairie Sandreed Plant Community. Depending on the length of time non-use occurred and the composition of the plant species prior to removal of use and/or fire, these practices will move this plant community to the Sand Bluestem/Prairie Sandreed Plant Community or the Prairie Sandreed/Blue Grama/Needleandthread Plant Community.

Submodel

Description

This plant community can be reached whenever severe mechanical disturbance occurs. The vegetation on this plant community varies greatly, sometimes being dominated by Scribner's panicum, bluegrass, three-awn, sand dropseed, horseweed (marestail), green sagewort, and/or ragweed. Other plants that commonly occur on the plant community include six-weeks fescue, prairie sandreed, witchgrass, little bluestem, switchgrass, and needleandthread. Compared to the Sand Bluestem/Prairie Sandreed Plant Community, warm-season natives have decreased. Annual grasses and forbs have become established in the plant community.

This plant community is variable in its resistance to change and is resilient depending on past management practices. The water cycle is not greatly affected.

Submodel