This report uses a system of alerts agreed after a series of extensive discussions between the providers and users of population monitoring information in the UK.  The system provides alerts to population declines of 25-49% and of  >50% over short, medium and longer terms (5 years, 10 years and 25+ years respectively).  These help to highlight the scale and timing of declines as an aid to interpreting the trend graphs presented.   For example, a species that triggers an alert over 25 years but not over the past 10 or 5 years, declined at some point in the past, but has not yet recovered. A species that triggers alerts over 25, 10 and 5 years, however, is still undergoing a potentially serious population decline. For the former species, identification of actions that will aid population recovery is of greatest importance, whereas for the latter species it is urgent that means of halting declines are established before consideration is given to actions aimed at increasing the population size. Alerts triggered over the short term for individual species should be considered as early warnings, indicating that conservation issues may be developing for these species. However, it is possible that such declines may be due to chance fluctuations in abundance from which the population is able to recover without assistance. The rapid, short-term decline of a suite of similar species should be considered as a stronger indication that potential problems may be developing.