A preliminary assessment of the establishment and persistence ofBerberis darwiniiHook., a naturalised shrub in secondary vegetation near Dunedin, New Zealand

Abstract

A preliminary assessment was made of the establishment and persistence ofBerberis darwinii in secondary vegetation dominated by native trees. B. darwinii seedling establishment on cleared ground and in forest considerably exceeded that of native shrub and tree species. B. darwinii showed continuous recruitment in stands surrounded by rough pasture, in low forest established since 1974 and 1942, and in secondary forest mature in 1942. It persisted in secondary forest for at least 40 years, but diameter growth rate and height relative to the canopy were lower with increasing vegetation age, so B. darwinii plants became increasingly confined to the understorey. Native species diversity was little reduced by B. darw/n/i in the vegetation age range of the study. Comments are made on the conservation implications orB. darwinii population dynamics, with suggestions for further research.

Clonal expansion and seedling recruitment of Oregon grape (Berberis nervosa) in Douglas-fir (Pseudotsuga menziesii) forests: comparisons with salal (Gaultheria shallon)

“…Other work on similar sites showed that species with large seed, e.g., vine maple and bigleaf maple, had higher rates of seedling establishment than did salal (Tappeiner and Zasada 1993). Also, high rates of seedling recruitment have been reported for Berberis darwinii Hoak (Allen 1991). Density of Oregon grape seedlings in this study was much higher than that of vine maple, a large-seed species, on similar sites (O'Dea et al 1995).…”

Effect of light on the growth and photosynthesis of an invasive shrub in its native range

“…This would explain why, according to Allen (1991) and Allen and Wilson (1992), B. darwinii is one of the few naturalized shrubs in New Zealand that can become established and persist under the canopy. This fact supports the idea that an increase in SLA promotes the invasiveness of exotic plants (Lake and Leishman 2004).…”

“…In its native area of Chiloé (Chile), a wetter region than its distribution range in Argentina, high seed germination and seedling growth occurs both under the forest canopy and in gaps with canopy openness greater than 20 % (Figueroa and Armesto 2001; Figueroa and Lusk 2001; Figueroa 2003). In New Zealand B. darwinii can become established and persist below the forest canopy (Allen 1991; Allen and Wilson 1992). According to McAlpine and Jesson (2007), seedlings of this species are shade intolerant, while adult plants growing under the canopy come from surviving seedlings with increased shade tolerance.…”

“…The photosynthetic responses of B. darwinii leaves to different light levels and other ecophysiological characteristics have been studied extensively in invaded areas of New Zealand (Allen 1991; Allen and Wilson 1992; McAlpine 2005; McAlpine and Jesson 2007; McAlpine et al 2008). …”

Potential contributions of the seed rain and seed bank to regeneration of native forest under plantation pine in New Zealand

“…However, the early-successional nature of the majority of these species means that few have the capacity to persist under the shade of a closed canopy. Alien species such as Berberis darwinii which are able to establish and grow under low light conditions (Allen 1991) pose a far greater threat to the restoration project than do ephemeral, weedy species such as Lamium purpureum, Cirsium vulgare, and Digitalis purpurea.…”