Pollination ecology and the possible impacts of environmental change in the Southwest Australian Biodiversity Hotspot

Abstract

The Southwest Australian Biodiversity Hotspot contains an exceptionally diverse flora on an ancient, low-relief but edaphically diverse landscape. Since European colonization, the primary threat to the flora has been habitat clearance, though climate change is an impending threat. Here, we review (i) the ecology of nectarivores and biotic pollination systems in the region, (ii) the evidence that trends in pollination strategies are a consequence of characteristics of the landscape, and (iii) based on these discussions, provide predictions to be tested on the impacts of environmental change on pollination systems. The flora of southwestern Australia has an exceptionally high level of vertebrate pollination, providing the advantage of highly mobile, generalist pollinators. Nectarivorous invertebrates are primarily generalist foragers, though an increasing number of colletid bees are being recognized as being specialized at the level of plant family or more rarely genus. While generalist pollination strategies dominate among insect-pollinated plants, there are some cases of extreme specialization, most notably the multiple evolutions of sexual deception in the Orchidaceae. Preliminary data suggest that bird pollination confers an advantage of greater pollen movement and may represent a mechanism for minimizing inbreeding in naturally fragmented populations. The effects of future environmental change are predicted to result from a combination of the resilience of pollination guilds and changes in their foraging and dispersal behaviour.

Biodiversity hotspots and Ocbil theory

“…theory has stimulated criticism, denial, accolades and journal articles extending its framework in new directions (Fiedler 2009;Mucina and Wardell-Johnson 2011;Langlois et al 2012). Additionally, the theory has generated novel hypotheses and new insights, for example in pollination ecology (Phillips et al 2010;Menz et al 2011). conservation strategies (Fiedler 2009;Adam 2012).…”

“…x Banksia hookeriana (Proteaceae) Krauss et al (2009) x Orchidaceae Phillips et al (2010) x Evolution of pollination strategies in some eucalypts…”

Paternity analysis reveals wide pollen dispersal and high multiple paternity in a small isolated population of the bird-pollinated Eucalyptus caesia (Myrtaceae)

“…Although field observations of honeyeater behaviour in numerous plant species support predictions of more widespread pollen dispersal than would be expected under insect pollination (Hopper and Moran, 1981;Ramsey, 1988;Phillips et al, 2010), few studies have addressed the realised genetic consequences of this behaviour for the plants that they pollinate. Paternity studies in southwest Australian banksias suggest that departures from optimal foraging by honeyeaters can lead to wide outcrossing and very high multiple paternity (Krauss et al, 2009;Ritchie and Krauss, 2012), and that population size, shape and isolation affect honeyeater visitation patterns and plant paternity (Llorens et al, 2012).…”

“…The South West Australian Floristic Region (SWAFR, sensu Hopper and Gioia, 2004) has the highest known global incidence of vertebrate pollination (Phillips et al, 2010). Approximately 15% of ca.…”

The plant endemism in the Maritime and Ligurian Alps

“…Snowpack may affect flowering time driving rearrangement in plant communities (Inouye et al 2002, Keller & Körner 2003. Furthermore, climate changes have the potentiality to act in concert with existing environmental alterations negatively affecting plantpollinator networks (Phillips et al 2010). As observed by Minuto et al (2013) in Primula allionii, even if currently there is no evidence of imminent threats, changes in plant-pollinator interactions due to climate change might increase inbreeding, resulting in an increased extinction risk.…”