Overview:  In 1998, while conducting an Oregon Natural Heritage invertebrate inventory in the Agate Desert region, researchers discovered a population of vernal pool fairy shrimp, a federally threatened species previously thought to only exist in California.  The life cycle of this crustacean is uniquely adapted to the temporary ponds and springs that appear in the Agate Desert eco-region immediately after the prolific winter rains.  Fairy shrimp embryos are protected throughout the dry, hot summer by a tough outer covering around each egg.  But soon after being immersed in waters that are below 10^oC, the eggs hatch, releasing hundreds of little fairy shrimp who eat, grow, reproduce and lay eggs before their ephemeral pools disappear--often in as little as two weeks.  Eggs are transported from pool to pool, or dry depression to dry depression, by 'hitching a ride' on wading animals.  The fairy shrimp may also be dispersed by animals that ingest the eggs, since the tough egg-coats protect the embryos from being digested. Fairy shrimp swim on their backs, feeding on small particles of detritus, algal cells and bacteria by scraping vegetation or other surfaces with their legs, or filtering the surrounding waters.  Many types of insects, amphibians, waterfowl and crustaceans prey on vernal pool fairy shrimp, making this species an extremely important link in the food web, particularly as a supply of energy for migratory birds.   Vernal pool fairy shrimp are threatened by continued human efforts to drain and fill vernal pool watersheds for agriculture and development purposes.  Stormwater run-off containing pesticides, chemical residues and other contaminants is heavily impacting remaining shrimp populations as well.