Timescale analyses of fluctuations in coexisting populations of a native and invasive tree squirrel.

Competition from invasive species is an increasing threat to biodiversity. In Southern California, the western gray squirrel (, WGS) is facing competition from the fox squirrel (, FS), an invasive congener.We used spectral methods to analyze 140 consecutive monthly censuses of WGS and FS within a 11.