|Title||Multi-scale temporal variation in water availability: implications for vegetation dynamics in arid and semi-arid ecosystems|
|Publication Type||Journal Article|
|Year of Publication||2006|
|Authors||Snyder K.A., Tartowski, Sandy L.|
|Journal||Journal of Arid Environments|
|ARIS Log Number||174498|
|Keywords||variation, vegetation dynamics, water availabililty|
The objective of this paper is to illustrate the importance of variation in water availability to temporal variation in vegetation dynamics. We hypothesize that fine-scale pulses of precipitation interact with longer-scale variation in climate and weather to generate temporal variation in plant community composition. Arid and semiarid regions exhibit a high degree of temporal variability in water availability as a result of variation in climate and weather at multiple scales and vegetation-soil water feedbacks. The scales of variation include: shifting climate regimes over centuries and decades, inter-annual variation in weather patterns, seasonal differences in winter and summer precipitation, and within-season variability in precipitation frequency and magnitude. In arid and semiarid regions pulses of rainfall are separated by intervening dry periods of variable lengths. This results in fluctuating availability of water that limits plant production and controls other ecological processes, such as rates of nutrient cycling. In many semiarid and arid systems, temporal variation in water availability may create positive feedbacks that facilitate encroachment of C3 woody plant species into areas formerly dominated by C4 grasses. Our ability to predict these complex shifts in vegetation composition may be improved by including temporal variation in climate, weather, and ecosystem processes.