Mountain ecosystems in a changing environment. eco.mont (Journal on Protected Mountain Areas Research)|eco.mont Vol. 6 No. 1 6 1|

One eighth of the terrestrial surface are mountains, if surface ruggedness is taken as a criterion. Topographic roughness and steep climatic gradients over short distances explain the exceptional biological diversity of mountains around the globe. Habitat diversity also safeguards mountain biota against species losses in case of climatic change, simply because of the mosaics of contrasting micro-environmental conditions that offer short distance escapes. Experimental evidence revealed no benefits of rising atmospheric CO2 concentrations for growth and productivity of alpine plants, but nitrogen deposition bears the risk that slow growing and robust species may become overgrown by vigorous, less robust taxa. Land-use change is likely to exceed the impact of any other environmental change. As exemplified by statistics for the Hohe Tauern region in Austria, almost one third of the current vegetation will undergo dramatic transformations, for no other reason than reduced land use. Land-use policy and land management thus have priority over any other considerations in the context of global change in protected areas