نتایج جستجو برای: distribution of predators

تعداد نتایج: 21195303  

2004
BARNEY LUTTBEG ANDREW SIH

The spatial distributions of predators and prey can be shaped by both intraand interspecific games. Most predator–prey studies, however, have ignored the interspecific game by focusing on how either predators or prey distribute themselves while holding the distribution of the other species fixed. We use genetic algorithms to examine how the distributional outcome of the game between predators a...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان - دانشکده مهندسی عمران 1392

abstract in aggregate, active forms of reactive silica with mineral names are sometimes associated with sand and gravel in concrete mixture. alkali hydroxides originated from alkalis in the cement or other resources form an alkaline silica gel with this reactive silica which becomes swallowed and expanded during time causing damage to concrete. there have been growing researches on alkaline r...

Journal: :Theoretical population biology 1999
C Cosner D L DeAngelis J S Ault D B Olson

A unified mechanistic approach is given for the derivation of various forms of functional response in predator-prey models. The derivation is based on the principle of mass action but with the crucial refinement that the nature of the spatial distribution of predators and/or opportunities for predation are taken into account in an implicit way. If the predators are assumed to have a homogeneous...

2014
Laurie Thiers Maite Louzao Vincent Ridoux Matthieu Le Corre Sébastien Jaquemet Henri Weimerskirch

In tropical waters resources are usually scarce and patchy, and predatory species generally show specific adaptations for foraging. Tropical seabirds often forage in association with sub-surface predators that create feeding opportunities by bringing prey close to the surface, and the birds often aggregate in large multispecific flocks. Here we hypothesize that frigatebirds, a tropical seabird ...

Journal: :Journal of theoretical biology 2009
Wendi Wang Yasuhiro Takeuchi

Mathematical models are proposed to simulate migrations of prey and predators between patches. In the absence of predators, it is shown that the adaptation of prey leads to an ideal spatial distribution in the sense that the maximal capacity of each patch is achieved. With the introduction of co-adaptation of predators, it is proved that both prey and predators achieve ideal spatial distributio...

2016
Sébastien Descamps Arnaud Tarroux Yves Cherel Karine Delord Olaf Rune Godø Akiko Kato Bjørn A. Krafft Svein-Håkon Lorentsen Yan Ropert-Coudert Georg Skaret Øystein Varpe

Commercial fisheries may impact marine ecosystems and affect populations of predators like seabirds. In the Southern Ocean, there is an extensive fishery for Antarctic krill Euphausia superba that is projected to increase further. Comparing distribution and prey selection of fishing operations versus predators is needed to predict fishery-related impacts on krill-dependent predators. In this co...

2014
Brett A DeGregorio Patrick J Weatherhead Jinelle H Sperry

1 Anthropogenic alteration of landscapes can affect avian nest success by influencing the abundance, distribution, and behavior of predators. Understanding avian nest predation risk necessitates understanding how landscapes affect predator distribution and behavior. 2 From a sample of 463 nests of 17 songbird species, we evaluated how landscape features (distance to forest edge, unpaved roads, ...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد تهران مرکزی - دانشکده ادبیات و علوم انسانی 1391

abstract: one of the most visited & important spaces in different countries by tourist are urban areas. the old tehran which major part is located in district 12 is historical showcase of the capital, but, its hiidden cultural attraction is not used as it should be. this thesis occasionally engage in studying the efficacy of correct installation of travel guide boards in welfare & easily acc...

2004
Brigitte Tenhumberg

Behavioral ecology and population ecology are two separate branches of ecology; studies linking the effect of individual behavior and population dynamics are rare. This paper connects a stochastic optimal foraging model of insect predators with an age structured population model of its prey. I modeled syrphid larvae feeding on cereal aphids, an interaction critical to cereal crops in Germany. T...

Journal: :کنترل بیولوژیک آفات و بیماری های گیاهی 0
صفورا سلیمانی دانشجوی سابق کارشناسی ارشد، دانشکده کشاورزی دانشگاه بوعلی سینا همدان حسین مددی استادیار ، دانشکده کشاورزی دانشگاه بوعلی سینا همدان

the distribution pattern of pest population is one of the factors not only effects on sampling program and data analysis method, but also can be used to measure the density of pests and their natural enemies. thus, the spatial distribution pattern of the pea aphid, acyrthosiphon pisum harris (hem.: aphididae) and its two major predators, hippodamia variegata goeze (col.: coccinellidae) and cocc...

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