Advancing treeline and retreating glaciers: Implications for conservation in Yunnan, P.R. China

Abstract

Historic climate data and repeat photographs were used to assess and document changes in alpine treeline and glacial recession in northwestern Yunnan, China. Results show that mean annual temperature in the last two decades of the 20th century has been increasing locally at a rate of 0.06°C yr -1 (p < 0.001). Furthermore, the annual trend is a result of both summer- and wintertime warming (0.037°C yr-1, p < 0.001; and 0.036°C yr-1, p < 0.001, respectively). Additionally, a local drying trend (-3.80 mm yr-1; p < 0.001) was observed during the period 1955-1995. Repeat photos and supplemental measurements show that this warming is causing the retreat of glaciers and contributing to the elevational advance of alpine treeline. Fire, a traditional management tool used to halt the advance of woody species, has been suppressed since 1988. One consequence of these interactions is the encroachment of woody vegetation into alpine meadows, which will have negative impacts on plant species diversity and Tibetan livelihood. Two spatially and temporally distant anthropogenic actions, a rapidly warming climate and local land use policy, appear to be threatening both biodiversity and Tibetan livelihoods. Land managers need to recognize that global warming is occurring and adapt their conservation practices and policies to anticipate and be resilient to threats at all critical scales. © 2007 Regents of the University of Colorado.