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Danthonioid biogeography: ecology and history. Appendix S2. Page 1 SUPPORTING INFORMATION What determines biogeographical ranges? Historical wanderings and ecological constraints in the danthonioid grasses H. Peter Linder, Alexandre Antonelli, Aelys M. Humphreys, Michael D. Pirie and Rafael O. Wüest Journal of Biogeography Appendix S2 Disjunction and barrier ages (a) and areas of endemism of Danthonioideae (b). (a) Disjunction and barrier ages In order to test the assumption that range expansions could occur only with long-distance dispersal, we compared the age ranges over which each disjunction was established to the age of the ‘barrier’ (Table S2-1). The age range over which the disjunction was established is taken be between the maximum 95% highest posterior density (HPD) of the stem node and the minimum 95% HPD of the crown node, on the dated tree. Danthonioid biogeography: ecology and history. Appendix S2. Page 2 Table S2-1 Comparison of the age of the disjunct distribution with the time when the barrier was established. ‘Disjunct taxon’ refers to a taxon that is spatially disjunct from its sister-taxa; ‘Age range’ refers to the maximum 95% HPD of the stem clade and the minimum 95% HPD of the crown clade. In the case of single species, this is taken as zero. ‘Disjunction’ refers to the two areas in which the sister clades occur, and ‘Barrier’ refers to the gap between. ‘Age’ refers to the seafloor if the barrier is marine (dates taken from McLoughlin, 2001); if it is terrestrial, a more detailed description is presented below (a–d). Disjunct taxon Chionochloa Pentameris insularis Rytidosperma Pentameris andringitrensis Danthonia alpina Pentameris pictigluma Tenaxia subulata Danthonia Tenaxia cumminsii Schismus arabicus Schismus barbatus Chimaerochloa Notochloe plastid Rytidosperma violaceum clade Austroderia Cortaderia plastid Danthonia clade Chionochloa frigida Notochloe–Plinthanthesis Rytidosperma australe Rytidosperma exiguum Rytidosperma gracile Rytidosperma pulchrum clade Rytidosperma pumilum Rytidosperma thomsonii clade Age range (Ma) 18.66–4.35 2.42–0 10.2–3.6 14.46–0 4.52–0.48 4.7–1.03 10.86–2.82 7.73–2.86 10.86–2.82 7.96–1.44 5.42–0 7.73–0 3.09–0 5.1–1.04 9.55–0.66 16.69–3.76 16.03–7.83 1.58–0 9.55–1.93 2.53–0 3.67–0 1.58–0 5.1–1.45 1.4–0 3.33–0.68 Disjunction Africa–New Zealand Africa–Amsterdam Island Africa–Australia Africa–Madagascar America–Europe S–E Africa S–E Africa S America–N America Africa – Himalayas S–N Africa S–N Africa S America–New Guinea Australia–S America Australia–S America S America–New Zealand Africa–S America Africa–S America Australia–New Zealand Australia–New Zealand Australia–New Zealand Australia–New Zealand Australia–New Zealand Australia–New Zealand Australia–New Zealand Australia–New Zealand Barrier Indian Ocean Indian Ocean Indian Ocean Mozambique Strait N Atlantic Ocean Overland Overland Overland Overland Overland Overland Pacific Ocean Pacific Ocean Pacific Ocean Pacific Ocean S Atlantic Ocean S Atlantic Ocean Tasman Sea Tasman Sea Tasman Sea Tasman Sea Tasman Sea Tasman Sea Tasman Sea Tasman Sea Age (Ma) 105–120 105–120 105–120 130–160 52–55 a a b c d d 30–50 30–50 30–50 95–76 105–119 105–119 95–76 95–76 95–76 95–76 95–76 95–76 95–76 95–76 Danthonioid biogeography: ecology and history. Appendix S2. Page 3 (a) South–East Africa disjunction Currently the danthonioids are restricted to the volcanoes in East Africa, and are absent from both the uplands flanking the rift valleys and the lowlands. The lowlands (the major valleys of the Limpopo, Zambezi, the extensive Tanzanian and Kenyan lowlands and the Congo basin) appear to have always been tropical, and fluctuated during the Neogene between savanna and rain forest (Wichura et al., 2010). Uplift of the plateaux flanking the rifts was initiated in the middle Miocene (Wichura et al., 2010), while volcano construction was during the whole of the Neogene (Grove, 1983). It is possible that the range of the danthonioids in East Africa was considerably expanded during the Pleistocene glacials, when lower temperatures (Hamilton, 1982; Bonnefille & Bonnefille, 1988; Bonnefille et al., 1995) might have allowed them to occupy the extensive uplands in Malawi (Shire Highlands, Nyika), Tanzania (Southern Highlands, Kitulo, Ufipa), Burundi, Rwanda, southern Uganda and the Kikuyu uplands of Kenya. This would have substantially reduced the interval between the southern African and East African populations. (b) South America–North America disjunction This became an overland disjunction with the closure of the Panama Isthmus, at c. 3.5 Ma. During the 6 Myr preceding the closure, occasional migration occurred, possibly facilitated by the relative proximity (c. 200 km) of the South and North American continents since the middle Miocene (Montes et al., 2012). Then, and also since the closure, the vegetation appears to have fluctuated between rain forest and savanna (Woodburne, 2010; Smith et al., 2012), neither of which constitutes suitable danthonioid habitat. This disjunction may well have stayed the same size as currently throughout the Neogene, especially as the estimated timing of the Danthonia disjunction is largely before the Isthmus was closed. (c) Africa–Himalayas disjunction The reconstructions for the South–North African disjunction also apply to the Africa–Himalayas disjunctions, and even during the Holocene optimum at 6 ka the desert was still only a savanna (Jolly et al., 1998). (d) South–North Africa disjunction This disjunction crosses the Sahara, which has had desert conditions at least since 7 Ma (Schuster et al., 2006), with wetter periods being more savanna-like but never temperate (Jolly et al., 1998). However, during wetter periods the Congo basin would have been more densely forested. This barrier is thus much older than the danthonioid disjunction. The oceanic disjunction sizes would not have changed much during the Neogene, except possibly the distance between the Madagascan uplands and the East African uplands. Danthonioid biogeography: ecology and history. Appendix S2. Page 4 (b) Areas of endemism Area name Area definition and notes Southern Africa South of Malawi, includes both the Cape flora and the temperate montane grasslands of the Drakensberg. Central–East Africa From central Tanzania to the Yemen, and Mount Cameroon, including the higher Rift Valley mountains. The single species of Merxmuellera is known only from the type collection. Mount Cameroon With a single species, Pentameris mannii, dubiously distinct from the East African P. pictigluma. Madagascar There are no species on the Mascarenes. Madagascar is very under-represented in the phylogeny. Amsterdam Island Only Pentameris insularis. Himalayas From Pakistan to Yunnan. Australia Including Tasmania, but not New Guinea. There are numerous species shared between the mountains of southern Australia and Tasmania, while the species of New Guinea are shared with the mountains in Southeast Asia. New Guinea and Southeast Asia Based on shared species. Lord Howe Island A single species (Chionochloa howensis), not sampled for the phylogeny. New Zealand Including surrounding islands. These either have no endemic species (Stewart Island) or are less than 1000 km from the main islands (Auckland, Chatham, Pitt and Campbell Islands). Easter Island A single, endemic, species (Rytidosperma paschale). This species is probably not distinct from R. racemosa and may be an anthropogenic introduction. South America From Tierra del Fuego to Panama. North America North of Panama, including NE Asia (Kamchatka), which shares a species with northern North America. West Indies A single species on Hispaniola (Danthonia domingensis) Central Europe In the summer-wet regions Mediterranean basin In the summer-dry regions south of the Pyrenees and Alps, and including North Africa. This is not geographically separable from Central Europe. Danthonioid biogeography: ecology and history. Appendix S2. Page 5 REFERENCES Bonnefille, R. & Bonnefille, G. (1988) The Kashiru pollen sequence (Burundi) palaeoclimatic implications for the last 40 000 yr B.P. in tropical Africa. Quaternary Research, 30, 19–35. Bonnefille, R., Riollet, G., Buchet, G., Icole, M., Lafont, R., Arnold, M. & Jolly, D. (1995) Glacial/interglacial record from intertropical Africa, high resolution pollen and carbon data at Rusaka, Burundi. Quaternary Science Reviews, 14, 917–936. Grove, A.T. (1983) Evolution of the physical geography of the East African Rift Valley region. Evolution, time and space: the emergence of the biosphere (ed. by R.W. Sims, J.H. Price and P.E.S. 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