Ecology

Skeletons of once-buried plants scattered around the dunes attest to the difficulty of life in active sand dunes. When you also consider the hot, dry summers and the cold, snowy winters, and that only 13.4 inches of precipitation falls on the dunes each year, it is clear that the St. Anthony Sand Dunes present many challenges to life.

Despite these challenges, plants and animals do live in and around the dunes. The first plants to invade the open sands are grasses, like sand wildrye (Elymus fiavescens), and scurfpea (Psoralea lanceolata). After about 30 years, those pioneer plants have stabilized the sand sufficiently for rubber rabbitbrush (Chrysothamnus nauseosus) and bitterbrush (Purshia tridentata) to begin their invasion. It can take as long as 700 to 900 years for the final, climax community of bitterbrush and chokecherry (Prunus virginiana var. demissa) to become fully established on the dunes.

Although you might expect the dunes to be inhospitable for animals, visitors will usually find the dunes crisscrossed with the tracks of small rodents, birds, and insects. In addition, many hooved animals migrate long distances to overwinter in and around the dunes, including antelope (Antilocapra americana), mule deer (Odocoileus hem ionus), elk (Cervus elaphus) and moose (Aices aices). In fact, the St. Anthony Sand dunes hosts the largest desert wintering elk population in North America.

These dunes provide such a unique living environment that there are several plants and animals that live only at St. Anthony Sand Dunes. The sand evening-primrose (Oenothera psammophiia) is found nowhere else, and its relative the pale evening-primrose (Oenothera pallida) occurs in a special pubescent, or hairy, form (var. idahoensis), that is known only from these dunes. In addition, the St. Anthony Sand Dunes boasts the largest and most viable population of a rare tiger beetle (Cicindeia arenicola) that is known from only two other locations, both in southern Idaho.