Topic
Embothrium
About: Embothrium is a research topic. Over the lifetime, 11 publications have been published within this topic receiving 234 citations.
Papers
TL;DR: The early history of the Proteaceae in Australia is traced from the record of fossil pollen that possess characters having taxonomic resolution among extant members of the family, suggesting that the family originated in northern Gondwana during the late Cenomanian and radiated by as yet unidentified routes into southern high latitudes during the Turonian.
Abstract: The early history of the Proteaceae in Australia is traced from the record of fossil pollen that possess characters having taxonomic resolution among extant members of the family. Pollen characters useful for segregating subfamilies and generic groups are apertural number and form together with exine stratification and structure. When considered in conjunction with pollen shape, polarity, and size and exine sculpturing, they may be used to discriminate generic and/or species groups. The fossil pollen record suggests that the family originated in northern Gondwana during the late Cenomanian and radiated by as yet unidentified routes into southern high latitudes during the Turonian. There the family underwent substantial differentiation and expansion during Santonian–Maastrichtian times when at least four of the seven extant subfamilies evolved. Although diversification in Australia principally involved rainforest lineages (e.g. Macadamia–Helicia, Carnarvonia, Gevuina) ancestors of some sclerophyllous taxa (e.g. Adenanthos) also differentiated; this occurred in a regionalised vegetation of mesotherm open-forests in which podocarps and araucarians were important. Subsequent (Paleocene–Eocene) diversification and consolidation of the family may have focused on introduction and expansion of sclerophyllous lineages (e.g. Isopogon, Petrophile), but rainforest elements (e.g. Embothrium) were also involved. The associated vegetation, which was regionalised, experienced considerable floristic modifications during this time with introductions and/or expansion of an array of angiosperm taxa, notably Casuarinaceae, Myrtaceae and Nothofagus. In southern regions a marked decline in proteaceous pollen diversity and abundance occurred near the end of the Eocene, whereas in north-eastern regions the decline may have been later, during the Miocene.
54 citations
TL;DR: The three tribes of Proteaceae found today in Argentina were already present in Patagonia by the early Eocene, where they probably arrived via the Australia-Antarctica-South America connection.
Abstract: Proteaceae are restricted to the Southern Hemisphere, and of the seven tribes of the subfamily Grevilleoideae, only three (Macadamieae, Oriteae, and Embothrieae) have living members in Argentina. Megafossil genera of Proteaceae recorded from Patagonia includeLomatia, Embothrium, Orites, andRoupala. In this report, we evaluate and revise fossil Argentine Proteaceae on the basis of type material and new specimens. The new collections come from the Tufolitas Laguna del Hunco (early Eocene, Chubut Province), the Ventana (middle Eocene, Rio Negro Province), and the Rio Nirihuau (late Oligocene-early Miocene, Rio Negro Province) formations, Patagonia, Argentina. We confirm the presence ofLomatia preferruginea Berry,L. occidentalis (Berry) Frenguelli,L. patagonica Frenguelli,Roupala patagonica Durango de Cabrera et Romero, andOrites bivascularis Romero, Dibbern et Gandolfo. Fossils assigned toEmbothrium precoccineum Berry andE. pregrandiflorum Berry are doubtful, and new material is necessary to confirm the presence of this genus in the fossil record of Patagonia. A putative new fossil species of Proteaceae is presented as Proteaceae gen. et sp. indet. Fossil Proteaceae are compared with modern genera, and an identification key for the fossil leaf species is presented. Doubtful historical records of Proteaceae fossils for the Antarctic Peninsula region and Patagonia are also discussed. Based on this revision, the three tribes of Proteaceae found today in Argentina were already present in Patagonia by the early Eocene, where they probably arrived via the Australia-Antarctica-South America connection.
51 citations
TL;DR: It was found that pollinator visiting rates were negatively correlated with forest patch area and were highest for pasture trees, and this trend was largely due a decline in the number of visits by E. albiceps, the main flower visitor, in larger patches.
Abstract: We investigated the effects of forest patch size on the behaviour of birds feeding on the flower nectar of the proteaceous tree Embothrium coccineum J R et G Forster, which is typically restricted to forest edges in agricultural landscapes in southern Chile We quantified reproductive parameters of trees (no inflorescences per branch, total and open flowers per inflorescence) in forest fragments varying from 1 ha (small), to 20 ha (medium) and to >150 ha (large), and in remnant trees in pastures Visits to flowers by nectar-feeding birds were recorded during 30-min observation periods, spread throughout the day during two flowering seasons, November 1992 and 1993 (n = 242 periods overall) Aggressive encounters among flower visitors were recorded in 1992 We expected less visits to trees in pastures and small forest patches because abundances of Embothrium's main pollinators, the flycatcher Elaenia albiceps and the hummingbird Sephanoides sephaniodes, decreased in smaller patches We found, however, that pollinator visiting rates were negatively correlated with forest patch area and were highest for pasture trees This trend was largely due a decline in the number of visits by E albiceps, the main flower visitor, in larger patches Hummingbird visits did not change with forest patch size Lower visitation rates to flowering trees in larger forest fragments seemed to be a consequence of territorial defence by E albiceps and were unrelated to differences in floral display
45 citations
TL;DR: The pollination ecology of eight populations of the tree Embothrium coccineum was studied along a steep rainfall gradient in NW Patagonia, Argentina and found a highly significant increase in nectar concentration towards the drier end of the gradient, but this change was not related to the turnover of species in the flower-visitor assemblage of E. coccines.
Abstract: The pollination ecology of eight populations of the tree Embothrium coccineum was studied along a steep rainfall gradient in NW Patagonia, Argentina. The showy red flowers suggest an ornithophilous pollination syndrome and they have been reported to attract hummingbirds in Argentina and hummingbirds and passerines in Chile. At each population, flower visitors were recorded and floral rewards were analysed. We found a highly significant increase in nectar concentration towards the drier end of the gradient, but this change was not related to the turnover of species in the flower-visitor assemblage of E. coccineum. In addition to the hummingbird Sephanoides sephaniodes (Green-Backed Firecrown, Trochilidae) which is widespread throughout the temperate forest at this latitude, other species seem to be locally important as pollinators of E. coccineum in some sites in Argentina (e.g. two long-tongued tanglewing flies (Nemestrinidae) of the genus Trichophthalma). The long-dated occurrence of tanglewing flies in South America, relative to the more modern hummingbirds, suggests that ornithophily may be a derived character in E. coccineum, the ancestral condition being pollination by Nemestrinidae.
33 citations
TL;DR: The shallow phylogeographic structure reported here reflects a Pleistocene signature highly impacted by drift resulting in the randomly fixation of new variants reducing the cpDNA structure.
Abstract: Embothrium coccineum J.R.Forst. & G.Forst is an endemic tree of the Patagonian temperate forest. The objective of this study is to evaluate the impact of last glaciation events on the genetic structure of this widespread and ecologically tolerant species, to postulate possible refugial areas. Phylogeographic analyses were performed using chloroplast DNA sequences (trnL-trnF spacer and ndhC-trnV spacer) from individuals collected in 34 populations along the total range of the species, and these results were compared with a similar study in Nothofagus. A total of 22 haplotypes were found, three of which were widely distributed while 13 were found at only one location. Historical demography suggests a long period of stable effective population size, decreasing gradually towards the Last Glacial Maximum (LGM), followed by an increase in population size that stabilised 2500 years ago. The phylogeographic analyses reflect recent events of colonisation after the LGM from multiple refugia. In the northern area of its distribution probably the species survived in several pockets within the Andes mountain range and in Cordillera de la Costa in Chile. In the south, it is suggested that Embothrium survived the glacial period at the edge of the glaciers. These findings are in agreement with the fossil pollen record that shows 10 000-year-old grains in the south, suggesting colonisation from nearby areas when ice retreated. Embothrium is a coloniser that naturally occurs as scattered individuals within mixed forests. Hence, the shallow phylogeographic structure reported here reflects a Pleistocene signature highly impacted by drift resulting in the randomly fixation of new variants reducing the cpDNA structure.
30 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2020 | 1 |
| 2019 | 1 |
| 2013 | 1 |
| 2011 | 1 |
| 2007 | 1 |
| 2006 | 1 |