[Show abstract][Hide abstract] ABSTRACT: AUSTRALIAN PLANTS DIFFER FROM THOSE in the northern hemisphere in the extent to which they are pollinated by birds and mammals (Levin & Kerster, 1974; Armstrong, 1979; Proctor et al., 1996; Menz et al., 2011). The primary pollination vectors in Europe are insects and wind (chapter 7A) and the importance of vertebrates as pollinators of many Australian flowers was slow to be appreciated (Ford et al., 1979). These differing modalities can have far-reaching genetic consequences for plants, and it has often been assumed that mating opportunities are largely restricted to nearest neighbours, because of the forces extrinsic to plants that limit pollen dispersal (Smouse & Sork, 2004). This is the case where wind and insects are the pollination vectors, and a skewed distribution is typical in northern-hemisphere plants with many grains dispersed close to the pollen source and a long tail of fewer, far-dispersed grains (Webb, 1998; Sork et al., 1999). A recent molecular analysis of paternity in a natural population of the Australian plant species, Banksia hookeriana (Proteaceae), however, has demonstrated a significant departure from these assumed patterns of pollen dispersal (He et al., 2004; Krauss et al., 2009), comparing the vertebrate-pollinated Banksia hookeriana with a bee-pollinated species, Persoonia mollis (Krauss, 2000) (Fig. 1). These data from Banksia hookeriana signal hitherto unexpected genetic consequences of pollination by vertebrate vectors and the need for a landscape approach to gene flow in plants (Sork et al., 1999). In the study, 96% of two-seeded fruits were multiply sired, indicating extensive pollen carry-over with promiscuity facilitated by highly-mobile nectar-feeding birds (White-cheeked honeyeater) moving effectively in a random manner (Krauss et al., 2009). In another study of fragmented populations in kwongan of the shrub Calothamnus quadrifidus, pollen was regularly dispersed by honeyeaters between fragments as much as 5 km apart (Byrne et al., 2007). The highly-diverse Southwest Australian Floristic Region (SWAFR) is an internationally-recognised biodiversity hotspot under multiple threats (chapter 8) (Myers et al., 2000; Phillips et al., 2010) and one where vertebrate pollinators are of great significance. Fifteen per cent of some 7380 plant species are considered to be either bird or mammal pollinated, a striking 40% of which are threatened endemics (Hopper & Gioia, 2004). This contrasts with other vertebrate-pollinated regions of South Africa and Central America where only 4% of the flora is bird pollinated (Bawa, 1990). Bird pollination is a prominent feature of the ancient Gondwanan families Proteaceae and Myrtaceae, and 110 species of birds have been recorded visiting the flowers of 1000 species of plants in more than 64 genera and 16 families (Ford et al., 1979; Keighery, 1982; Brown et al., 1997). The 'otherness' of the Australian environment and its plants and animals has long attracted and intrigued biologists, but it is only now that the underlying reasons for this are beginning to be understood (Stafford Smith & Morton, 1990). The immense age of the continent, particularly its western Yilgarn craton with some of the oldest rocks on the planet (Myers, 1995), and the weathering that has depleted
Plant Life on the Sandplains in southwest Australia, a Global Biodiversity hotspot., Edited by Lambers, H, 09/2014: chapter 7D: pages 207-213; UWA Publishing.
[Show abstract][Hide abstract] ABSTRACT: Resumen. – Limitaciones filogenéticas en la adaptación morfológica y ecológica en colibríes (Trochi-lidae): ¿por qué no hay ermitaños en el páramo? – Los ermitaños (subfamilia Phaethorninae), aunque posiblemente eran capaces de ocupar todo el rango altitudinal disponible cuando se separaron de los no ermitaños (subfamilia Trochilinae), no pudieron aumentar sus distribuciones altitudinales y diversificarse en las elevaciones altas durante el levantamiento de los Andes, mientras que los no ermitaños si lo lograron. Aquí examino la morfología externa de 21 especies de ermitaños y 115 de no ermitaños (1265 individuos en total) para explorar las posibles causas de esta diferencia. Once medidas morfológicas, incluyendo varias medidas de las alas y patas imposibles de tomar de pieles de estudio, la masa corporal y cuatro parámetros aerodinámicos fueron usados en los análisis. El análisis discriminante logró separar las dos subfamilias casi completamente con base en sus morfologías. El análisis de regresión reveló que los no ermitaños han variado de manera significativa con respecto a la elevación en casi todas las medidas, al contrario de los ermitaños en que ningún parámetro mostró algún cambio significativo con respecto a la elevación. Esta aparente in1flexibilidad morfológica de los ermitaños pudo haber limitado su habilidad para ocupar montañas altas. Se discuten las razones que podrían explicar este fenómeno. Abstract. – The hermits (subfamily Phaethorninae), despite presumably being able to occupy the full range of elevations present at the time of their divergence from the Trochilinae (nonhermits), have failed to expand and speciate into higher elevations as the Andes rose, while the nonhermits succeeded. Here I use a detailed examination of external morphology of 21 hermit and 115 nonhermit species (1265 individ-uals in all) to explore the reasons for this diference. Eleven morphological measurements, including several of wings and feet impossible to obtain from study skins, body mass and four calculated aerodynamic parameters for each bird were used in a discriminant analysis that demonstrated that the two subfamilies are quite distinct morphologically. Regression analysis revealed significant variation with elevation in nearly all parameters in the nonhermits, whereas variation in the morphology of the hermits was independent of elevation in every parameter. This apparent inflexibility of hermit morphology might have limited their ability to occupy high mountains, and possible reasons for this are discussed. Accepted 15 January 2004.
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