On the few occasions someone has pointed a microphone at me and asked why I 'chose to study moss', I've found myself struggling to respond. I imagine they expect a heroic answer, like when people say they wanted to be an astronaut since a child, or experienced an epiphany and felt drawn to a life on stage!
When I get asked what I'm doing when I'm out and about in the suburbs, it's nice to be able to share some basic facts about moss. Usually, people think of it as only found in moist habitats, so they are surprised to learn that desert mosses inhabit our city pavements. But as members of the IAB will be well aware, moss is both ubiquitous and picky. Ubiquitous in that there are thousands of species (10 000 at least according to the Tree of Life Web Project) and these grow in an astonishing variety of places: among other biocrust organisms (such as lichen, fungi, bacteria) in deserts; on trees in rainforests and on ground that is newly exposed, as glaciers retreat in Antarctica. But picky too, in that substrate – the kind of rock, for instance – also largely dictates whether a particular species can grow there. For example, I'm looking at moss on an urban gradient on three substrates - pavement cracks, asphalt dimples (such as car park edges) and soil in grassy green spaces. The species vary according to substrate (albeit with a few that have wide ranges and can tolerate all three). But whether it's the CBD or Antarctica, where moss grows depends on a combination of factors including microclimate (the humidity, temperature and so on, at the scale it matters to a moss) and microtopography.
Written by Alison Haynes
PhD Candidate (University of Wollongong), Australia