Projections for Visualizing Ecosystem Dynamics

A technique for visualizing the dynamics should allow for the comparison of dynamical relationships. These comparisons should include factors such as inherent variability between replicates or samples and an indication of the rate of change in variables. We have developed a method for this purpose which we call space-time worms.  

Space-time worms (STW) were developed to more easily visualize the dynamic relationships between the variables in microcosm experiments (Landis, Matthews, and Matthews 1996). G. Matthews and M. Roze developed the software that enables a three-dimensional viewing of the microcosm experiments. 

Measures of distance between clusters. Two of the commonly used measures of separation of clusters in an n-dimensional space are the cosine of the angle and the vector distance. Each method has advantages and disadvantages. In order to visualize the data as accurately as possible, several measures should be employed. 

Construction of a space-time worm (STW). In A, the average values for the variables ankistrodesmus and ostracod are plotted along with a box plot to represent one standard deviation. Each treatment group can be represented and compared. If time is added (B), then a plot for each sampling date can be represented but the diagram becomes much harder to interpret. 

A major contribution of these projection techniques is the realization of the importance of dynamics and trajectories in understanding the impacts of 

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