Pattern of natural regeneration of narrow-leaved snow tussockChionochloa rigidassp.rigidain Central Otago, New Zealand

Abstract

Regeneration of Chionochloa rigida ssp. rigida (Poaceae) was investigated in two adjacent un burnt sites subjected to different levels of grazing by merino sheep over an 8 year period. The spatial pattern of establishment of immature plants within a 3 m radius of 100 isolated mature tussocks (basal diameter >20 cm) was recorded. Basal diameter, height, canopy width, slope, and aspect of the putative parents were noted, was was the size and position of the immature plants (basal diameter <10 cm). At the lower grazing intensity the number of immature plants increased with tussock size. Regeneration was successful in the absence of fire and at low grazing intensity, probably <0.2 stock units ha-1 yrl. However, recruitment was low under moderate grazing and uphill and upwind of mature tussocks. These factors need to be considered in the rehabilitation of narrow-leaved snow tussock grasslands in Central Otago.

Effect of climate change on mast‐seeding species: frequency of mass flowering and escape from specialist insect seed predators

“…There are 22 species of Chionochloa endemic to New Zealand, and most species have mass flowering and mast seeding (Connor 1966;Mark 1968;Kelly et al 1992). The plants grow as long-lived tussocks (Connor 1991), with only occasional regeneration from seed (Rose & Platt 1990;Lee et al 1993).…”

“…1992). The plants grow as long‐lived tussocks (Connor 1991), with only occasional regeneration from seed (Rose & Platt 1990; Lee et al . 1993).…”

Snow Tussocks, Chaos, and the Evolution of Mast Seeding

“…Seedling establishment in Chionochloa is inhibited by competition with established vegetation (including adults) and by introduced mammalian herbivores (Rose and Platt 1992;Lee et al 1993). Removal of the vegetation cover by fire can enhance establishment (Mark 1965a;Yeates and Lee 1997).…”

Is the Invasive Species Listronotus bonariensis (Kuschel) (Coleoptera: Curculionidae) (Argentine Stem Weevil) a Threat to New Zealand Natural Grassland Ecosystems?

“…Should the density of L. bonariensis increase, adult feeding could play a role in reducing seedling establishment for some native species. The impact of moderate animal grazing pressure on C. rigida seedling survival (Lee et al, 1993 ) is known to be significant (Lee et al, 1993 ). The relatively minor mortality rates found in C. rigida seedlings exposed to L. bonariensis for 2–3 weeks is trivial in comparison.…”