THE ALPINE LIFE ZONE UNDER GLOBAL CHANGE

Resumo

Nearly forty percent of mankind depend in one way or another on mountain ecosystems. Local ecosystem services are slope stability, water yield, agricultural products or recreational value. Continental scale influences include drinking water supply, ground water recharging, irrigation water, hydroelectric power, flood control, traffic routes etc. In this paper I review evidence of alpine ecosystem responses to global change. It is emphasized that soil conservation is the centerpiece of any consideration of sustainable land use in alpine terrain. Complete vegetation cover of high biological diversity is essential to protect soils and secure `ecosystem services' in upland systems. It is illustrated that this is not necessarily in conflict with land use and that land use may even contribute to biological richness if appropriate management is adopted. Atmospheric influences such as increased nitrogen deposition, elevated CO₂ and climate warming induce subtle changes in alpine vegetation, the understanding of which requires experimental concepts which account for long term acclimation and organismic interaction. It is proposed that comparative approaches which cover interspecific variability and natural environmental gradients are most promising.