The role of seed predation in the maintenance of the Cross Timbers ecotone of Oklahoma, USA

Abstract

I investigated how seed predation differed among tree species and among microhabitats across the Cross Timbers and what that variation may tell us about how this ecotone is maintained. The ecotone is located in Oklahoma, USA, between the eastern deciduous forest and tallgrass prairie where seeds of eight common tree species were placed in three microhabitats (oak forest, tallgrass prairie, and sumac shrub/small-tree/grass mix). After nine days in the field, percent seeds remaining were scored for each of the 120 (8 species )3 microhabitats )5 replicates) dishes. I found for both wind-dispersed tree species, (ash, elm) there was significantly more predation in the prairie microsite, with similar small predation levels in the shrub and forest. For two of the three bird-dispersed species (dogwood, hackberry), there was significantly more predation in the prairie and shrub microsites compared to the forest. Red cedar, however, was not taken by predators very much anywhere. Finally, all three mammal-dispersed tree species (two oaks, pecan) showed significantly more predation in the shrub and forest microsites compared to the prairie. Whereas wind-and bird-dispersed species suffered less predation as microsites became more woody and dark, the dominant oaks showed the opposite trend. Consequently, seed predators are not preventing oaks from advancing across this ecotone, but yearly fluctuations in predator population density, especially in the shrub transitional zone, could be helping to maintain it.

Spatial patterns and associations of four species in an old-growth temperate forest

“…In this study, limited seed dispersal is also considered the most likely explanation. In plants, as in other sessile organisms, dispersal is mostly passive: seeds or other diaspores (dispersal units) are transported away from the parent plant by vectors such as animals, wind, and water (Damgaard et al 2005;Nathan 2006;Myster 2013). The coniferous species P. koraiensis disperses its seeds via animals (e.g.…”

Population structure and spatial pattern of predominant tree species in a pine–oak mosaic mixed forest in the Qinling Mountains, China

“…These patterns are affected by wind, water flow, light intensity, animals and species characteristics such as type of regeneration, seed dispersal and unknown factors resulting from technical limitations of the aforementioned factors (Hutchinson 1953;Myster 2013;Duman et al 2016).…”

Evidence for pre-dispersal predation of seeds of Tithonia diversifolia by the black-faced canary (Serinus capistratus)

“…The impact of seed removal by BFC on TD invasiveness as well as the role of its ability to clonally propagate in balancing the effects of seed loss should be empirically researched (Wang et al 2004;Weppler & Stöcklin 2006). Finally, understanding that intensity of seed predation may significantly vary over time and among microhabitats within BFC home range (Myster 2013), further study should be conducted to investigate TD seed removal in relation to spatial and temporal patterns of TD seed set (Wang et al 2004) and BFC density (Haught & Myster 2008). …”