نتایج جستجو برای: population dynamics

تعداد نتایج: 1090949  

2014
Kate T. Snyder Nicole A. Freidenfelds Tom E. X. Miller K. T. Snyder N. A. Freidenfelds

Harvesting for food or sport is often non-random with respect to demographic state, such as size or life stage. The population-level consequences of such selective harvesting depend upon which states are harvested and how those states contribute to population dynamics. We focused on a form of selective harvesting that has not previously been investigated in an experimental context: sex-selectiv...

2011
Martin M. Turcotte David N. Reznick Daniel Hare

Background: It is generally assumed that short-term population dynamics are too slow to be influenced by evolution. Question: Can evolution occurring within only weeks (four to five generations) impact concurrent population dynamics? Organism: Green peach aphid (Myzus persicae) growing on an undomesticated host (Hirschfeldia incana). Aphid clones were collected from a single wild population. Si...

2003
Luděk Berec David S. Boukal

In this paper we examine how the process of mate search, degree of mate choice and degree of mate fidelity may interact to affect long-term population dynamics of sexually reproducing species. In particular, we address the following questions: are degree of mate choice and degree of mate fidelity correlated? How does mate search shape this relationship? How does longevity affect mating behaviou...

2004
Qinfeng Guo Mark Taper

Understanding the boundaries of species'rangs and the variations in population dynamics from the centre to margin of a species' range is critical. This study simulated spatial-tamporal patterns of birth and death rates and migration across a species' range in different seasons. Our results demonstrated the importance of dispersal and migration in altering birth and death rates, balancing source...

2003
Atle Mysterud Øystein Holand Knut H. Røed Hallvard Gjøstein Jouko Kumpula Mauri Nieminen

In sexually dimorphic ungulates, male reproductive success depends on fighting with other males for access to females during a brief rutting season. Large body size is necessary for success in intrasexual competition, and a few large-sized males are often able to monopolize access to female groups. Earlier studies have reported that reproductive effort increases with age until prime-age is reac...

2010
Andreas Sundelöf Stuart R. Jenkins Carl J. Svensson Jane Delany Stephen J. Hawkins Per Åberg

The importance of external and internal population processes in determining variation in reproductive output and variation in population size were quantified with model simulations for open populations of the sequentially hermaphroditic limpet Patella vulgata using field data from the Isle of Man and South West Ireland. Cross-correlation analyses of model outputs and elasticity analyses show th...

2010
Randy L. Anderson

Weeds are a major obstacle to successful crop production in organic farming. Producers may be able to reduce inputs for weed management by designing rotations to disrupt population dynamics of weeds. Population-based management in conventional farming has reduced herbicide use by 50% because weed density declines in cropland across time. In this paper, we suggest a 9-year rotation comprised of ...

2015
Justin R. Seibert Quinton E. Phelps Kasey L. Yallaly Sara Tripp Levi Solomon Tom Stefanavage David P. Herzog Michael Taylor Marion Wittmann

Management of silver carp Hypophthalmichthys molitrix has become a growing concern for multiple state and federal entities. Commercial fishing may have the greatest potential to control silver carp. However, for a management action to be successful, the level of exploitation required to reduce silver carp populations must be quantified. Therefore, silver carp were collected from Midwestern U.S....

2004
ANTHONY JOERN

While weather can contribute signiÞcantly to grasshopper population dynamics in North American grasslands, local environmental conditions resulting from land use practices may be equally important. In this study, signiÞcant differences in grasshopper density were detected among adjacent watersheds from Kansas Flint Hills tallgrass prairie that differed in Þre frequency and especially bison graz...

2010
William Z. Lidicker

The role of mutually beneficial interactions (++, cooperation) is a rapidly growing research field in population dynamics, microevolution, and conservation biology. Such positive influences cause destabilizing pressures in population dynamics (anti-regulating factors), and can generate Allee effects. Not only can large demes benefit from such cooperation, but the loss of cooperation in small de...

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