Dynamics of a Tasmanian cushion heath community

Abstract

. Little is known of the dynamics of the alpine cushion plant communities of Tasmania. The present study investigates the nature of the short (5 yr) and long (850 yr plus) term dynamics within one such community at Newdegate Pass, Tasmania. This involved observations of permanent plots, quadrat sampling of cushion heath in different stages of a secondary succesion and cuticular analysis of a core through the cushion peat. Data from the peat core showed the continued presence of the cushion heath community at this site for at least 850 yr, while the regeneration patterns indicated community composition was largely achieved by species accumulation rather than species replacement. Over a 5–yr period there was little or no change in total percentage cover yet a surprisingly high degree of interspecific competition for space in areas of complete plant cover. These observations best fit non equilibrium models of community succession and stability.

Successional sequences in two Tasmanian valley Sphagnum peatlands

“…Herbs and cushions were the only species or species groups not identified below the surface. While cushions are known to preserve well (Gibson & Kirkpatrick 1992), herbs may be absent because of poor preservation.…”

A systematic review of the recent ecological literature on cushion plants: champions of plant facilitation

“…mean density of 0.55 cushions m -2 in the sub-Antarctic Marion Island, Nyakatya andMcGeoch 2008, Phiri et al 2009) and have large impacts on local species diversity (percentage of positive plant associations with cushions depends largely on environmental harshness with a mean of 47% in harsh environments and 22% in less harsh environments from Arroyo et al 2003 andCavieres et al 2006). Cushions influence the plant community over a long temporal scale as they have been shown to take part in successional processes (Smith 1987, Gibson and Kirkpatrick 1992, Mark and Bastow 2005, Badano and Cavieres 2006. Cushions are also nurse-plant species as they have been shown to facilitate other plant species (Núñez et al 1999, Cavieres et al 2005, AcunaRodriguez et al 2006, Antonsson et al 2009).…”

“…By improving growth conditions in severe habitats, cushions are excellent facilitators (Moen 1993, Choler et al 2001, Cavieres et al 2002, Badano and Cavieres 2006, Antonsson et al 2009, Sklenar 2009) and may potentially stabilize species diversity ). This enables cushions to aid in species succession at multiple spatial scales (Smith 1987, Gibson and Kirkpatrick 1992, Mark and Bastow 2005, Badano and Cavieres 2006) and act as a keystone species contributing to the structure and function of the ecosystem (le Roux and McGeoch 2004, le Roux et al 2005, Badano and Marquet 2008, Mortimer et al 2008, Nyakatya and McGeoch 2008, Phiri et al 2009). Furthermore, the role of cushions as facilitators in these harsh ecosystems is not redundant as more erect plants cannot modify the abiotic conditions associated with positive effects on germination and survival (Moen 1993).…”

Ecology of a paramo cushion mire

“…The cushion bogs, on the other hand, formed by cushion forming chamaephytes ( Fig. l), are only reported from the southern hemisphere and the tropical high mountains (Cleef 1978(Cleef , 1981Godly 1978;Kirkpatrick 1983;Pisano 1983;Gibson & Kirkpatrick 1992).…”