UK body backs food from cloned animals

data. Although there were some differences they concluded: “Because onset and end dates of the growing season were averaged over the entire Tibetan Plateau, the temporal resolution of the data was deemed sufficiently high for detailed analysis.” So they tested whether winter warming might affect the plants’ chilling requirements in this cold, highaltitude environment. They determined the beginning, end and length of the growing season of meadow and steppe vegetation between 1982 and 2006. They then correlated these dates with monthly temperatures for the entire period on record. For both vegetation types, the timing of spring growth initially advanced but started retreating in the mid-1990s in spite of continual warming. The steppe vegetation also showed an advancing end to the growing season but, combined with the later spring start, overall the growing season shortened. The researchers found that temperatures in both winter and spring had strong effects on the timing of spring. Although warm springs led to an advance in the growing season, warm conditions in winter caused a delay of the spring phases. “This delay appeared to be related to later fulfilment of chilling requirements,” they say. The researchers believe that these results, although from an extremely cold environment, may have implications for other regions as temperatures continue to rise. “Recent studies have identified historic and projected losses in winter chill in many parts of the world,” they write. Changes in seasonal timings and growing periods “may be in store for many regions in the future.” They believe further studies of climatechange effects on plant growth timings “may be well advised to take the additional effects of winter warming into consideration”. They go on to say: “Such studies could help substantially reduce the amount of unexplained variation in growth timings with temperature and help produce much more accurate projections of future trends than are currently available.” And the small but significant number of species in the earlier studies that did not respond to rising temperatures may increase as temperatures continue to rise. UK body backs food from cloned animals