There are two major players of Nature's attack in its war against rocks. The two players are lichens from the Fungi Kingdom and mosses from the Plant Kingdom. Once lichens have created a foothold in rocks, the mosses move in, ultimately becoming a layer of topsoil for higher plants to take root. Lichens consist of a symbiosis between a fungus and an algae. The algae contains the pigment chlorophyll which it uses during  photosynthesis to produce carbohydrates. These are required by algae but are also absorbed and used for growth by the fungus. Thus the fungus obtains nutrients from the algae, the fungal tissue in turn may provide shelter for the algae allowing it to grow in harsh conditions such as rock surfaces. The association between high lichen diversity and pristine habitats is well known among scientists and therefore, lichens are used as indicators of ecosystem health. Certain lichen species grow primarily (or even exclusively) in undisturbed habitats and as such; provide critical baseline biological information. It can take hundreds of years for lichen communities to form (some are even used to date archeological dwelling sites).  Mosses reproduce through alternating generations. The first generation, the gametophyte, forms the green leaf structure we ordinarily associate with moss. It produces a sperm and an egg (the gametes) which unite, when conditions are right, to grow into the next generation: the sporophyte or spore-bearing structure. The sporophyte contains no chlorophyl of its own: it grows parasitically on its gametophyte mother. As the sporophyte dries out the capsule releases spores which will grow into a new generation of gametophytes, if they germinate.
Trampling vegetation at the base of climbs or removing it from the rock can be minimized if you are careful. Vertical walls represent unique biological communities. Lichens and mosses are important because they contribute to a large part of the species diversity in the Volcanic Tableland and play an important role in ecosystem function. They also are important indicators of climatic change, play a large role in ecosystem processes, and will be even more important when trying to predict changes in the ecosystems based upon climate change. Please do not remove or disturb these unique organisms | 
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