SYDNEY, AUS: In the day to day here, as I commute to work, take the bus around town, and observe, I’m frequently overwhelmed by daily demonstrations of niche theory and convergent evolution in the world around me. The terrestrial flora in Sydney is of an entirely different lineage, primarily of the Myrtoideaen tribe Eucalypteae, than what I know from the Pacific Northwest. Though Eucalypts have long been present on Earth, their radiation in Australia is apparently relatively recent. Eucalypts now make up ¾ of the vegetation on this island continent, and fill nearly every ecological function that I, as a North American, attribute to other trees. For instance, coastal swamplands similar to the cypress swamps of Louisiana and Texas are here inhabited by swamp gum trees, other Eucalyptus spp., and their Myrtoideaen cousins, the paperbark trees. Savanna and temperate grassland habitats that in the US would have scattered oaks, cottonwoods, or willows, are here are inhabited by bimble box and coolibah eucalyptus trees. The Sydney red gum is one of several Eucalypts that plays the role of North American fruit trees, providing food for fruigivores. On my commute home at night, I often get to watch enormous ‘flying foxes’, or Ku-ring-gai bats (Pteropus poliocephalus), indulging in the tree’s nectar.
This, of course, is entirely tangential from my work on man-made alterations to urban shorelines in Sydney Harbour. While I know I should be entirely focused on the project that brought me here, the natural history nerd within has a hard time ignoring what Darwin and many others since found astonishing upon first traveling to the opposite hemisphere: That a similar set of ecological professions (niches) exist everywhere, and who fills them (which species) is heavily influenced by chance.
