Adult individuals that do not breed in a given year occur in a wide range of natural populations. However, such nonbreeders are often ignored in theoretical and empirical population studies, limiting our knowledge of how nonbreeders affect realized and estimated population dynamics and potentially impeding projection of deterministic and stochastic population growth rates. We present and analys...

The physiological condition and fecundity of an organism is frequently controlled by diet. As changes in environmental conditions often cause organisms to alter their foraging behavior, a comprehensive understanding of how diet influences the fitness of an individual is central to predicting the effect of environmental change on population dynamics. We experimentally manipulated the diet of the...

a pedigree file of 382831 holstein cows and bulls, collected from herds registered by animal breeding center of iran during 1967 to 1999, was used to calculate the inbreeding coefficient. the mean inbreeding coefficient for the whole population (male and female), on a base year of 1946, was 0.184%. the means for cows (94 percent of the whole population) and bulls (6 percent of the whole populat...

The red-cockaded woodpecker (Picoides borealis) is a federally endangered species. As such, populations need to be increased in order to achieve recovery goals outlined by the U.S. Fish and Wildlife Service. My thesis is composed of two chapters that represent opposite sides of this issue. The first chapter investigates whether military training activity negatively affects red-cockaded woodpeck...

BACKGROUND Several authors, most prominently Jared Diamond (1997, Guns, Germs and Steel), have investigated biogeographic determinants of human history and civilization. The timing of the transition to an agricultural lifestyle, associated with steep population growth and consequent societal change, has been suggested to be affected by the availability of suitable organisms for domestication. T...

Described is a computer software package, EPIZOO, which has been developed specifically for undergraduate and postgraduate education, self-training, problem-solving, and simulation studies in veterinary epidemiology. The program is based on action-oriented animal population health/disease analyses and programming. EPIZOO runs on IBM-compatible personal computers and can be used for any animal p...

The pelagic juvenile stage of sea turtles is poorly studied. We present a growth model and estimates for duration of the pelagic juvenile stage for loggerhead sea turtles Caretta caretta in the North Atlantic based on length-frequency analyses and sizes of young-of-the-year stranded in the Azores. The size-specific growth model is a monotonic, nonlinear, declining function. The growth model is ...

To study the effects of wheat-maize intercropping on the population dynamics of wheat aphids and their natural enemies, wheat-maize intercropping patterns were divided into four levels: 8:2, 6:2, and 4:2 intercropping, and monoculture wheat. The results showed that as the wheat coverage rate decreased, the quantities of immigrating winged aphids and their natural enemies significantly differed;...

development along with improvement of sanitary and veterinary services are needed for production of protein acious food substances and reducing of domestic loss. this is important in food security in a society. this needs systematic planning for delivering proper services to livestock producer units as well as proper spatial distribution of veterinary services. the purposes of this study were a...

Rising populations and incomes throughout the world have boosted meat demand by over 75% in the last 20years, intensifying pressures on production systems and the natural resources to which they are linked. As a growing proportion of global meat production is traded, the environmental impacts of production become increasingly separated from where the meat is consumed. In this paper, we quantify...