A new year, a new eco-system

As a gardener and plant lover, I felt like I knew something about the plant-life, and to a lesser-extent the animal life, in Australia and more locally around Melbourne. So it is very strange to move to another country, and another climactic zone, and not really know anything about this place. Of course this gives me the opportunity to learn things, which I like, but it still leaves me wandering along the street, looking at bushes and trees, and even if I have some idea of what they are, not knowing whether they are indigenous to the area, exotic imports, or whatever.
I'd actually feel more disoriented if there weren't so many Australian indigenous trees planted in Hong Kong. Everyday I have to walk past what look like a couple of specimens of the lemon-scented gum (Eucalyptus citriodora), and in the local neighbourhood there are also a lot of melaleucas planted as street trees (probably Melaleuca quinquenervia). Down at the my local park, Tai Po Waterfront Park, there is a planting of bottlebrushes (Callistemon viminalis?). Even on a walk in the local national park, a signboard told me I was seeing Eucalyptus Robusta, which has been planted to help stabilize the hillside and allow the local plant species to recover and recolonise. Perhaps this will be true in most places that I go around the world. Australian plants have adapted to cope with extremes of temperature, poor soils, lack of rainfall and so many varying conditions that they will probably be planted in many surprising places around the world.
I really need to do some serious exploration about this, but here is what I have discovered so far. The wildlife here is interesting, with many gorgeous butterflies, all of which are hard to photograph, so perhaps you can go and check out this local hiker's much better photos.
In terms of snakes, there seems to be a few venomous ones, but none to get seriously worried about, certainly not compared to Australia. There is a large snake called a Common Rat Snake (Ptyas mucosus) that is not dangerous to humans, but I imagine would be quite alarming to come across, given that they grow to about three metres long!
More excitingly for M, there are monkeys in Hong Kong, which she really wants to go and see (and of course there is a bus that goes from here to there!). These seem to be two species of Macaques (Macaca mulatta, M. fascicularis), though apparently these are not native to Hong Kong and must have naturalised from elsewhere, though they seem to be thriving.
My fascination though, is mostly with plants, so I was interested to read something of the history of forest cover in Hong Kong, from the Hong Kong Green Power (an environmental organisation) here.
This details the forests that were here originally when it was Chinese territories, sometimes nurtured for Feng Shui(風水) purposes and at other times cut down for fear of wild beasts! Often too, the forest cover seems to have been diminished by forest fires, a similarity with Australia that I was not expecting, and one that probably explains the planting of Australian trees here. Apparently a lot of trees were cut down during the Japanese occupation in World War II though there must be a lot more to this story that I don't yet know, given how respectful Japanese people are of their own forests. These days in Hong Kong there is a lot of attention to tree planting, but like in many modern cities, there is a difficulty in maintaining both nature reserves as well as urban plantings.
I know of two local plants so far, because they were 'discovered' here, namely the Hong Kong Camellia (C.hongkongensis) and the Hong Kong Bauhinia (B.blakeana), the latter of which is beginning to come into flower at the moment, and looking beautiful. However there is more to an ecosystem than these two plants, and that is what I need to learn...