The abundance of predators and their impact on ecosystem dynamics is a vividly discussed topic in current ecology. In my studies, incorporating field observations, field experiments and theoretical modeling, I explored the importance of predators and predation in a low arctic tundra ecosystem in northern Norway. This involved observing the abundance and spatial activity of predators (raptors an...

1. The behaviour of predators is rarely considered in models of predator–prey interactions, nor is it common to include multiple predators in models of animal behaviour. 2. We introduce a model of optimal diel vertical migration in zooplankton prey facing predation from two functionally different predators, fish and other zooplankton. Zooplankton predators are themselves subject to predation fr...

Background & Aim: Purslane (Portulaca oleracea L.), belongs to the Portulacaceace family, grows in many parts of Iran. Results of previous studies were indicated purslane is a rich source of essential fatty acids of omega-3 and omega-6.  Portulaca oleracea is a widespread weed, being the eighth common plants of the world. The Aim of current study was to compare the essential f...