Distribution of Western Juniper Seeds Across an Ecotone and Implications for Dispersal

Abstract

Abstract. Western juniper woodlands have been the focus of extensive research and management due to range expansion and infilling that began over a century ago. Understanding juniper seed dispersal is vital to identifying processes behind this expansion. Dispersal of Juniperus seeds has generally been attributed to consumption of female juniper cones (“berries”) by frugivorous birds and mammals, which then defecate seeds after gut passage. However, recent studies have found that scatter-hoarding rodents harvest and cache juniper seeds. Rodents caching and failing to recover juniper seeds that have been removed from feces may constitute a secondary mode of dispersal that accounts for more seedling recruitment than primary dispersal by frugivores. We considered implications of juniper seed dispersal by frugivorous birds and subsequent removal of bird-passed seeds and secondary dispersal by scatter-hoarding rodents by examining the distribution of western juniper seeds after dispersal by birds along transect...