Alkali Sink communities

The ecology of Alkali sink communities is relatively poorly understood compared to that of alkali meadows and scrub communities.  Although alkali sink, scrub, and meadow communities have many species in common, the community structure of sink communities differs in its much more heterogeneous canopy structure due to the broad range of sizes of the grass and shrub species present.  Sink communities also have a characteristically undulating surface composed of low  "sinks" devoid of perennial vegetation where water ponds, surrounded by higher, often sandy micro-uplands which support perennial grasses and shrubs.  This community is also interesting because it includes grasses adapted for shallow groundwater, shrubs adapted for deeper grounder water  i.e. Sarcobatus vermiculatus and shrubs adapted to no groundwater at all i.e. Atriplex confertifolia.  

Characteristic species include Sarcobatus vermiculatus (greasewood), Atriplex parryi, Atriplex confertifolia (shadscale), Chrysothamnus nauseosus (rabbitbtush), Sporobolus arioides (sacaton), and Distichlis spicata (saltgrass) (Manning 1997).  Like alkali meadow and shrub communities they occur areas of saline soil and shallow groundwater, frequently on old lake bed deposits (Sawyer and Keeler Wolf 1995).   Unlike alkali meadow and scrub communities, however, the soil surface is relatively impermeable and subject to ponding.  Hydrologically,  alkali sinks are analogous to vernal pools in California's Central Valley in that they fill with water when it rains, but floristically the two communities bear no known relationship.