REPRODUCTION AND POPULATION STRUCTURE OF POCKET GOPHERS (Thomomvs bottae) FROM IRRIGATED ALFALFA FIELDS

Pocket gophers were collected from irrigated alfalfa fields (IRR) and non-irrigated fallow fields (NIRR) in Davis, California, for 2 years. Reproduction was continuous in IRR fields with very little seasonal variation in reproductive activity. In contrast, reproduction in NIRR fields occurred primarily during the rainy season (winter and spring). Females in IRR fields produced approximately twice as many litters per year (3.6-3.9) as females in NIRR habitats (1.7). The high reproductive potential of adult females in IRR fields coupled with the early age of sexual maturity among young females suggests that population recovery after control measures is likely to be relatively rapid in irrigated alfalfa fields. Immigration into the optimal habitat of irrigated alfalfa fields is also likely to add to rapid recovery if gopher populations in nearby areas are not controlled as well. Proc. 14th Vertebr. Pest Conf. (L.R. Davis and R.E. Marsh, Eds.) Published at Univ. of Calif., Davis. 1990.