Slow‐motion population dynamics in Mojave Desert perennial plants

Autor: Martin L. Cody
Rok vydání: 2000
Předmět:
Zdroj: Journal of Vegetation Science. 11:351-358
ISSN: 1654-1103
1100-9233
DOI: 10.2307/3236627
Popis: To investigate survivorship and regeneration in desert perennial plants, individual shrubs were mapped, meas- ured and tagged on a nearly level 360 m2 plot of diverse Mojave Desert vegetation in 1981, they were re-mapped and measured 15 years later, in 1996. A large majority of the shrubs persisted between censuses. Modest birth (establish- ment) and death rates indicate that plants are replaced approxi- mately every century, while the median longevity of several species is much longer. A 15-yr intercensus interval, appropri- ate for most species (i.e. birth and death rates were measur- able), is too short for several larger shrubs (including Larrea divaricata, Ephedra nevadensis, Yucca schidigera and the larger Opuntia spp.) in which virtually no births or deaths occurred and in which longevity must be extremely high. While individuals of most species grew over the 15-yr interval, others did not, and some individuals shrank in size. In a number of species, individual growth rates were signifi- cantly reduced according to the number of neighbouring plants rooted 0.5 - 2.0 m distant. Even Larrea tridentata, one of the largest species, showed significant effects of growth rate reduction where crowded by allospecific plants, despite the generally much smaller sizes of these neighbours.
Databáze: OpenAIRE
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