| DRI | ARID-LAND SPRINGS—PRECIOUS JEWELS OF THE DESERT |
FERTILE
GROUND FOR RARE SPECIES Each spring is distinctive because of interacting environmental factors including elevation; morphology; level of disturbance; and water chemistry, rate of discharge, and temperature. Because many arid-land springs are isolated, plant diversity and endemism are frequently higher than in other aquatic systems. Surveys over the past 15 years have shown that small springs have greater biological importance than previously thought. For example, Sada and others documented 250 species of plants and animals associated with springs in the Spring Mountains of southern Nevada in 1996. Through taxonomic studies spanning the past 140 years, large numbers of endemic plants, vertebrates, and macroinvertebrates have been discovered at arid-land springs throughout western North America. These extant species represent relict populations that have persisted in the isolated habitats of these springs (possibly in conditions similar to those we see today) for thousands of years. Unable to live outside aquatic environments for long periods, these populations are restricted primarily to springs that have good water quality and are never dry.
The Great Basin supports a particularly extensive aquatic fauna that includes approximately 125 endemic species and 45 subspecies. The importance of springs to rare species indicates that survey protocols should determine the presence or absence of these species at each spring. |