River Continuum Concept
Practice customizing barplots (ggplot2)
The data of this work centers on the River Continuum Concept (Vannote et al., 1980), in which they describe a gradient in physical and chemical conditions (in terms of energy input) and their results in the biotic responses in the stream system, from headwaters to mouth. This way, the structural and functional characteristics of stream communities are adapted to conform to the most probable position or mean state of the physical system.
In this case, I've only work with data about the macroinvertebrate community structure and amount of available food resources. The sampling is divided in three different sections of a river following a gradient of headwater-downstream at four different seasons (January, April, July and October).
Through the script, the built plots will reflect the concept of RCC: collectors-gatherers and shredders are the most abundant in headwaters, scrapers and collector-gatherers at midspan, and collectors in downstream area. This structure is totally influenced by food resources. The shredders are more abundant where the CPOM has been greater; scrapers followed epilithon pattern, as well as the collectors have followed the FPOM; predators maintained along the river, increasing their abundance with the other groups (preys); collectors-filterers maintained a low abundance agreeing with the low level of FPOM-seston. In the other hand, the observed seasonal change could be reasoned by fluctuation changes.
Here are the created plots in this script:
*Note: the original data belongs to the University of the Basque Country, in which I studied my Master degree in environment.