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Egg production by desert tortoises was estimated at two sites in San Bernardino, California: Ivanpah Valley in 1980 and 1981 and Goffs in 1983, 1984 and 1985. Mean clutch frequencies were estimated for 1980 (1.60) and 1981 (1.10) from mass changes observed among sexually mature females weighed every 1-2 wk. Mean clutch frequencies in 1983 (1.89), 1984 (1.57) and 1985 (1.75) were estimated from periodic X-rays of females. Clutch sizes were also determined from radiographs. Tortoises at Goffs typically laid 1-2 clutches during May and June, but one female failed to lay eggs in 1984 and single tortoises laid three clutches in 1983 and 1985. If tortoises laid two clutches, the second was faintly visible in X-rays within...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Clutch frequency,
Clutch size,
Desert tortoise,
Egg production,
Hatching success, All tags...
Herpetologica,
Mojave Desert,
X-rays,
rainfall, Fewer tags
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Habitat modeling offers an approach to understanding some management problems of desert tortoises (Gopherus agassizii) and to focusing new research efforts. Modeling can provide (1) a method to organize existing information, (2) a means to identify whether physical habitat or some factor outside the scope of the habitat model is limiting populations, (3) a method to integrate habitat into resource development planning, and (4) a mechanism for focusing research on missing species-habitat information. Published in Herpetologica, volume 42, issue 1, on pages 134 - 138, in 1986.
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Desert tortoise,
Gopherus agassizii,
Habitat model,
Habitat quality,
Herpetologica, All tags...
Impact assessment,
Planning,
Suitability,
graphs, Fewer tags
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