BACKGROUND AND AIMS The Janzen-Connell model predicts that common species suffer high seed predation from specialized natural enemies as a function of distance from parent trees, and consequently as a function of conspecific density, whereas the predator satiation hypothesis predicts that seed attack is reduced due to predator satiation at high seed densities. Pre-dispersal predation by insects...

An economy of scale may lead to selection to increase interannual variation in seed production when the per seed probability of seedling establishment increases with seed production. Variable annual seedfall will, however, reduce this probability when postdispersal seed fate is negatively density dependent on the local density of seeds, and seed dispersal and density dependence act identically ...

Negative density dependence (NDD) of recruitment is pervasive in tropical tree species. We tested the hypotheses that seed dispersal is NDD, due to intraspecific competition for dispersers, and that this contributes to NDD of recruitment. We compared dispersal in the palm Attalea butyracea across a wide range of population density on Barro Colorado Island in Panama and assessed its consequences...

in order to study the effect of different redroot pigweed (amaranthus retroflexus) density on yield, yield components of soybean cultivar and determining competitive cultivar, a field experiment was carried out at mazandaran agricultural research station 2006. experiment was set up at a randomized complete block design with five rates of pigweed (0, 4, 8, 12 and 16 plant per square meter) and t...

In order to study on effect of plant density and nitrogen on yield and yield components of Visia faba (faba bean), the experimental design was implemented by randomized complete block with three replications at 2010- 2011 in Lahijan. The experimental factors were three plant density (25×25 cm, 35×35 cm and 45×45 cm) and four nitrogen fertilizer (0, 20, 40, 60 kg ha-1). In this experiment, featu...