01830nas a2200169   4500008004100000245007800041210006900119300001300188490000700201520128600208653001101494653000801505653001201513100002001525700001601545856009901561       1986                        eng d00aHow fox squirrels influence the invasion of prairies by nut-bearing trees0 aHow fox squirrels influence the invasion of prairies by nutbeari  a326 -3320 v673 a<p>The purpose of this study was to gain information on how squirrels respond to nuts buried on prairie-forest ecotones as a means of understanding how squirrels influence the invasions of prairies by nut-bearing trees. Of the three common species of nut-bearing riparian forest trees studies, seedlings of black walnut, Juglans nigra, the species whose nuts are most highly preferred by fox squirrels, Sciurus niger, tended to occur farthest from the forest edge onto the prairie. Squirrels removed walnuts buried in the woods in direct proportion to the density of nuts buried, rather than in proportion to the distance the nuts were located from a conspecific nut-bearing tree. In contrast, when walnuts were experimentally buried at extremely high densities in prairies next to woods during a good mast year, squirrels removed those nuts more quickly that were nearer the forest and did not remove nuts buried farther than 9 m from the edge of the canopy. Because walnut seedlings were observed at much greater distances from the forest edge, we speculate that squirrels may bury nuts on open prairies at considerable distances from forest cover in poor mast years, when the benefit of fewer nuts lost to other squirrels outweighs the added rick of predation in the prairie</p>10aanimal10afox10aprairie1 aStapanian, M.A.1 aSmith, C.C.  uhttp://knz.lternet.edu/content/how-fox-squirrels-influence-invasion-prairies-nut-bearing-trees