Phenological stages of natural species and their use as climate indicators

The objectives of this paper are to: (1) present 10 years of phenological d ata for nine natural species growing in a Mediterranean-type climate, (2) p resent threshold temperatures that were derived for the computation of cumu lative degree-days (CDD), and (3) evaluate the sensitivity of the nine natu ral species to weather variability. The study was conducted at the Phenolog ical Research Garden of Oristano, Sardinia, Italy, during the period 1986-9 6. The observations were made on five typical Mediterranean species and fou r species that are typical of higher latitudes. The mean annual pattern of phenological events and the CDD from 1 January are given for each developme nt stage. Temperature thresholds were evaluated by comparing the standard d eviation about the mean number of days in the development period for each s pecies. A good relationship between timing of phenophase occurrence and;tem perature was observed for the Mediterranean species, which were little affe cted by variations in rainfall. Phenological development of the nonnative s pecies was affected by springtime rainfall.