Reproductive characteristics of Road-verge and Reserve-interior populations of Exocarpos cupressifirmis Labil (Santalaceae)

Abstract

Fragmentation of native vegetation by roads exposes species to the conditions of a different surrounding ecosystem where the road verges onto the original habitat. An important issue for conservation biology is how native species respond to these human-made ecosystems. In this study I compa red reproductive characteristics, including seed output, seed mass, predispersal seed predation and dispersal appendage mass, between road-verge populations of the woody perennial, Exocarpos cupressiformis Labill., and nearby populations within undisturbed vegetation, in the Black Mountain Reserve in Canberra (Australian Capital Territory). Road-verge populations produced significantly more seeds per area of canopy cover and tended to have larger dispersal appendages than non-verge populations in the reserve interior. There were no significant differences in seed mass or levels of predispersal seed predation between road-verge and reserve-interior populations. However, seed mass and predispersal seed predation varied significantly among populations within the two locations. These findings demonstrate that populations of E. cupressiformis in disturbed habitats on road verges had an increased capacity for colonisation and a higher potential rate of increase through greater seed output and a tendency for larger investment in dispersal. (The Victorian Naturalist 120 (I), 2003. 10-14)