D. Habitat 



1. Associated vegetation: Smooth goosefoot occupies early- 

 successional , sparsely-vegetated habitat, locally devoid of 

 legumes. The species associated with its Harding County 

 population outside of the study area include: 



Sporobolus cryptandrus 



Chenopodium ambrosioides 



Ambrosia acanthicarpa 



Oryzopsis hymenoides 



Rumex venosus 



Psoralea lanceolata (the most common surrounding legume) 



2. Topography: This species occurs in exposed settings where 

 there is loose sand that has been reworked by wind or water: 

 either upland sand dunes, or extremely sandy river terraces 

 along a watercourse. 



3. Soil relationships: The unconsolidated sandy substrate of 

 smooth goosefoot is nutrient-poor and droughty. 



E. Population biology and biological interactions 



1. Population size and condition: Populations are typically 

 small and low density. They are likely to shift population 

 centers over time with succession. 



2. Reproduction: Unknown mode of sexual reproduction. 



3. Competition: Smooth goosefoot is unable to persist under 

 continuous vegetation cover. It is absent at the Harding Co. 

 site in microhabitat occupied by Psoralea lanceolata , and is 

 potentially impacted by encroachment of Melilotus officinalis 

 and Euphorbia esula elsewhere in its range. 



4. Herb ivory: While leaves of some members of the genus are 

 noted for their high nutrient value, there is little evidence 

 of herbivory. Its habitat in Harding County is part of a 

 grazing allotment. There are water developments in the 

 vicinity, and the blowouts are used to a limited extent as 

 loafing areas. 



F. Assessment and management recommendations: The Sand 

 Creek watershed in the East Short Pines has not been completely 

 surveyed for Chenopodium subglabrum . If there is well-developed 

 sandy habitat within Forest Service boundaries, then the species 

 warrants consideration by Custer National Forest as watch. It is 

 otherwise unlikely to be found on the Sioux District. 



65 



