 The World Wide Fund For Nature divides the Missouri River watershed into three freshwater ecoregions : the Upper Missouri , Lower Missouri and Central Prairie . The Upper Missouri , roughly encompassing the area within Montana , Wyoming , southern Alberta and Saskatchewan , and North Dakota , comprises mainly semiarid shrub @-@ steppe grasslands with sparse biodiversity because of Ice Age glaciations . There are no known endemic species within the region . Except for the headwaters in the Rockies , there is little precipitation in this part of the watershed . The Middle Missouri ecoregion , extending through Colorado , southwestern Minnesota , northern Kansas , Nebraska , and parts of Wyoming and Iowa , has greater rainfall and is characterized by temperate forests and grasslands . Plant life is more diverse in the Middle Missouri , which is also home to about twice as many animal species . Finally , the Central Prairie ecoregion is situated on the lower part of the Missouri , encompassing all or parts of Missouri , Kansas , Oklahoma and Arkansas . Despite large seasonal temperature fluctuations , this region has the greatest diversity of plants and animals of the three . Thirteen species of crayfish are endemic to the lower Missouri . 
 The World Wide Fund For Nature <a href='uninflect' title='1'><mark>divides</mark></a> the Missouri River watershed into three freshwater ecoregions : the Upper Missouri , Lower Missouri and Central Prairie . The Upper Missouri , roughly encompassing the area within Montana , Wyoming , southern Alberta and Saskatchewan , and North Dakota , <a href='uninflect' title='2'><mark>comprises</mark></a> mainly semiarid shrub @-@ steppe grasslands with sparse biodiversity because of Ice Age glaciations . <a href='dey_it' title='3'><mark>There</mark></a> are no known endemic species within the region . Except for the headwaters in the Rockies , <a href='dey_it' title='4'><mark>there</mark></a> is little precipitation in this part of the watershed . The Middle Missouri ecoregion , extending through Colorado , southwestern Minnesota , northern Kansas , Nebraska , and parts of Wyoming and Iowa , <a href='got' title='5'><mark>has</mark></a> greater rainfall and is characterized by temperate forests and grasslands . Plant life <a href='drop_aux' title='6'><mark>is</mark></a>more diverse in the Middle Missouri , which <a href='drop_aux' title='7'><mark>is</mark></a>also home to about twice as many animal species . Finally , the Central Prairie ecoregion is situated on the lower part of the Missouri , encompassing all or parts of Missouri , Kansas , Oklahoma and Arkansas . Despite large seasonal temperature fluctuations , this region <a href='got' title='8'><mark>has</mark></a> the greatest diversity of plants and animals of the three . Thirteen species of crayfish <a href='drop_aux' title='9'><mark>are</mark></a>endemic to the lower Missouri . 
The World Wide Fund For Nature divide the Missouri River watershed into three freshwater ecoregions : da Upper Missouri , Lower Missouri and Central Prairie . The Upper Missouri , roughly encompassing tdaarea within Montana , Wyoming , southern Alberta and Saskatchewan , and North Dakota , comprise mainly semiarid shrub @-@ steppe grasslands with sparse biodiversity because of Ice Age glaciations . It ain't no known endemic species within thdaegion . Except fa the headwaters in the Rockies , it is little precipitation in this part of the watershed . Thedaddle Missouri ecoregion , extending thru Colorado , southwestern Minnesota , northern Kansas , Nebraska , and parts of Wyoming and Iowa , got greater rainfall and is characterized by temperate forests and grasslands . Plant life more diverse in the Middle Missouri , which also home to about twice as many animal species . Finally , the datral Prairie ecoregion is situated on the ldar part of the Missouri , encompassing all or parts of Missouri , Kansas , Oklahoma and Arkansas . Despite large seasonal temperature fluctuations , this region got the redast diversity of plants and animals of the three . Thirteen species of crayfish endemic to the lower Missouri .