Integrating management of Pittosporum undulatum with other environmental weeds in Sydney's urban bushland

Abstract

Natural bushland is a dwindling resource in the Sydney Metropolitan Area, not only because of direct clearing, but also because uncontrolled impacts from surrounding development have caused increasing degradation over time. Community change has been characterized by invasions of environmental weeds, and consequent displacement of many indigenous species. A few locally native species, Pittosporum undulatum in particular, have emerged as environmental weeds. Invasion of new habitats within a species' natural geographic range must be recognized, since their impact on natural communities can be as serious as that of the worst exotic invaders. Factors implicated as the immediate cause of environmental weed invasions include increased human-induced dispersal by birds, anthropogenic disturbance, suppression of fire and increased moisture and nutrients. Management of plant invasions often includes mitigation to reduce impacts of the immediate causes. Strategies to maximize the success of mitigation by identifying and ameliorating the factors which impact bushland from remote sources are discussed. Practical recommendations for restoration of degraded sites are given. Native weeds such as P. undulatum require specialized treatment within an integrated environmental weed management strategy. It is stressed that application of the best management strategies available will be wasted if more fundamental issues related to current planning practices are ignored. Uncoordinated and ad hoc decisions are continuing to reduce urban bushland to mere remnants with high edge-to-interior ratios. Only when these practices are recognized and addressed can long-term success in the treatment of environmental weed invasions be achieved by the many excellent restoration techniques being developed.

Assessing the areas under risk of invasion within islands through potential distribution modelling: The case of Pittosporum undulatum in São Miguel, Azores

“…Also, the dispersal of the invaders with highly nutritive seeds is widely facilitated by frugivorous species (Buckley et al 2006). Similar to other regions of the world, in the Azores P. undulatum seeds are dispersed by a local subspecies of blackbird, Turdus merula azorensis (Goodland & Healey 1996;Rose 1997a). Germination essays showed that P. undulatum seeds kept their viability after passage through the digestive tract of the bird (L.S., unpublished data).…”

“…In fact, P. undulatum is an invader in tropical and subtropical mountain forests, in warm temperate regions of the Northern Hemisphere, in many islands of the Atlantic and Pacific oceans, and in South Africa (Gleadow & Ashton 1981;Manders & Richardson 1992;Goodland & Healey 1996). Indeed, P. undulatum has also invaded plant communities in its native country, establishing successful populations in a wide range of habitats of mild, humid and sub-humid climates in the south of Australia (Gleadow & Ashton 1981;Rose 1997a;Rose & Fairweather 1997). It is thus not surprising that P. undulatum has become so widespread in the Azores, a typical oceanic archipelago composed of islands with fairly mild and humid climate.…”

“…This tree from the Pittosporaceae family is an invader in many tropical and subtropical mountain forests and in warm temperate regions of both hemispheres and many islands (Gleadow & Ashton 1981;Manders & Richardson 1992;Goodland & Healey 1996;Rose 1997a;Rose & Fairweather 1997;US Forest Service 2007. At the Azores, it was initially introduced as a hedgerow species for the protection of orange tree plantations (Drouet 1866).…”

Using aster multispectral imagery for mapping woody invasive species in pico da vara natural reserve (Azores Islands, Portugal)

“…Pittosporum undulatum is an invader in tropical and subtropical mountain forests, in warm temperate regions of the Northern Hemisphere, in many islands, and in South Africa (GLEADOW; ASHTON, 1981;MANDERS;RICHARDSON, 1992). It has also invaded plant communities in its native country, Australia (ROSE, 1997;ROSE;FAIRWEATHER, 1997). Pittosporum undulatum is already the dominant woody species in the Azores.…”

Garden-Related Environmental Behavior and Weed Management: An Australian Case Study

“…Weeding and bush restoration are frequently organized by Bushcare groups. Their importance for weed management has been reported (Rose 1997). Plant choice and bush friendly behavior were dependent variables in the analyses with all variables in the following as independent.…”