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Full-Text Articles in Life Sciences

Pronghorn (Antilocapra Americana) Offspring Recruitment On The Carrizo Plain National Monument: Evaluating The Effects Of Low Population Density And Marginal Habitat Quality., Diego Ramirez Johnson May 2014

Pronghorn (Antilocapra Americana) Offspring Recruitment On The Carrizo Plain National Monument: Evaluating The Effects Of Low Population Density And Marginal Habitat Quality., Diego Ramirez Johnson

UNLV Theses, Dissertations, Professional Papers, and Capstones

Demographic fluctuation among ungulate populations is strongly linked to variability in recruitment. Rates of recruitment are subject to various forms of density-dependent and density-independent regulation. For species which benefit from the presence of conspecifics, reduced population density can decrease rates of recruitment and trigger a decline in per capita growth. Termed the Allee effect, this scenario can cause demographic collapse and population extinction. For many ungulate species, predation on juveniles is reduced when the timing and distribution of births is synchronized within a local population. Because birth synchrony is density-dependent, it may act as a mechanism for the Allee effect …


Life History Tradeoffs And The Costs Of Reproduction In Arizona Bark Scorpions (Centruroides Sculpturatus), Michael Marie Webber May 2014

Life History Tradeoffs And The Costs Of Reproduction In Arizona Bark Scorpions (Centruroides Sculpturatus), Michael Marie Webber

UNLV Theses, Dissertations, Professional Papers, and Capstones

Tradeoffs in life history evolution result from conflicts in the time and energy that can be simultaneously invested in activities such as growth, reproduction, and survival. Reproduction is an energetically costly activity for organisms, and is known to elicit alterations in the daily activity patterns of individuals. I investigated reproductive tradeoffs in the Arizona Bark Scorpion,Centruroides sculpturatus. To better understand the nature of tradeoffs in this species, I examined the influence of reproductive state on the predatory efficiency and thermal preference of reproductive females. Further, I examined the influence of reproductive activities (i.e. gestation) on the ability of reproductive females …