Journal article
Longevity and growth strategies of the desert tortoise ( Gopherus agassizii) in two American deserts
Journal of arid environments, v 73(4), pp 463-471
2009
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
The desert tortoise occurs in two strikingly different desert regimes in the southwestern United States. In the Mojave Desert, rainfall is more irregular and resources are more limited than in the Sonoran Desert. We examined the age structure of tortoise populations from these two deserts to determine whether the difference in resource availability has driven an evolutionary divergence in life history strategies. Age and growth rates strongly reflect the ecological adaptation of the two populations. The oldest Sonoran males reached 54
years, compared to only 43
years in females. The oldest West Mojave (WM) males reached 56
years, compared to only 27
years in females. WM tortoises grew faster than Sonoran ones, and females reached sexual maturity at earlier ages (∼17–19
years) than Sonoran females (∼22–26
years). These traits and the higher rate of clutch production in the WM population are likely the evolutionary adaptation for low juvenile survivorship and a significantly shorter life span. Frequent droughts in the WM Desert and the lowest annual rainfall area within the range of the desert tortoise cause chronic physiological stress, likely annually, and are proposed as a major selection force producing contrasting life-history strategies.
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Details
- Title
- Longevity and growth strategies of the desert tortoise ( Gopherus agassizii) in two American deserts
- Creators
- A.J. Curtin - Drexel UniversityG.R. Zug - National Museum of Natural HistoryJ.R. Spotila - Drexel University
- Publication Details
- Journal of arid environments, v 73(4), pp 463-471
- Publisher
- Elsevier
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- [Retired Faculty]
- Web of Science ID
- WOS:000264614300010
- Scopus ID
- 2-s2.0-61349110685
- Other Identifier
- 991019169714004721
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- Collaboration types
- Domestic collaboration
- Web of Science research areas
- Ecology
- Environmental Sciences