ECOLOGY A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA Reports Woody encroachment decreases diversity across North American grasslands and savannas Neighborhood effects on seed dispersal by frugivores: testing theory with a mistletoe–marsupial system in Patagonia Articles Pollinator effectiveness varies with experimental shifts in lowering time Wolves–coyotes–foxes: a cascade among carnivores April 2012 Volume 93 No. 4