Suchergebnisse

"Ecology is about understanding how organisms interact with other organisms and the environment they inhabit (i.e. fundamental and realised niches). It is easy to imagine an individual organism of any kind as a dot with all sorts of arrows impinging upon it, an arrow can represent abiotic factors (temperature, light, etc.), as well as many arrows for all the other organisms (biotic factors, intra- and inter-specific interactions) that affect it. Ecology aims therefore to determine the magnitude and rate associated with some of the arrows, and which are the most important and why. Each organism also has its own effects on the same list of factors, even if the effects may be small, so we can also imagine arrows going out from the same dot, one to each of the same list of factors (they can be dots too). Again, a challenge is to determine the associated weights and importance for the arrows, some of which are directed toward other organisms. As soon as we consider more than a single organism, even just a few, we immediately have a complex structure of dots and arrows: an ecological network! It is an obvious step to consider ecological systems as ecological networks, and as such to assess how network theory (concepts and methods) might be applied to them. Network theory and the mathematics of graph theory that underlie network analysis provide simple concepts that can applied to systems that are complex both in structure and dynamics. It is those concepts that allow us to provide a sorted set of methods for the quantitative analysis of 10 ecological networks, along with thoughts and advice on how best to proceed. Through the years, the need to take a network analysis framework to study complex system has arisen in many fields (physics, computer science, communication science (transportation, electricity, social), and bio- and ecoinformatics), and there is a challenging diversity of approaches, methods, and measures that should be understood, or at least sorted, before applying them to our own data. The overarching goal of this book is to help ecologists in selecting the appropriate network methods to represent, analyse, and model their ecological system using network theory"--