Singular spectrum analysis: Climatic niche identification

Abstract

This chapter discusses singular spectrum analysis (SSA) and uses a 32 year record (1940-1971) of flowering of four eucalypt species (Eucalyptus leucoxylon, E. microcarpa, E. tricarpa and E. polyanthemos) to illustrate its use. SSA delineated the trend, annual and biennial cycle in all four species. Additionally a 4 year cycle was detected in E. tricarpa. The trend and annual cycle were identified by SSA decomposition of the underlying climate profile (rainfall and mean, minimum, maximum temperatures). An examination of the correlation between the reconstructed flowering series and lagged climatic components found that for E. leucoxylon and E. tricarpa there was a similar relationship to climate. These two species exhibit a significant negative relationship with the temperature variables and a positive relationship with rainfall. The strongest relationship for E. leucoxylon was with minimum temperature (ρ = -0.742). In E. tricarpa maximum temperature was the marginally stronger driver (ρ = -0.895). Both E. microcarpa and E. polyanthemos also share a similar relationship to climate but this differs to that of E. leucoxylon and E. tricarpa; in that these species were positively influenced at flowering by temperature and negatively by rainfall. For E. microcarpa minimum temperature is the main but weak influence (ρ = 0.383) and E. polyanthemos maximum temperature is the stronger influence (ρ = 0.674).