The Construction and Assembly of an Ecological Landscape

1. An ecological landscape consisting of discrete interconnected patches was constructed in the laboratory. Each patch in the landscape was a 1-litre aquatic microecosystem containing producers and consumers. 2. Species invaded and spread throughout the landscape in a specific sequence following prescribed invasion pathways. 3. Species distribution among landscape patches was heterogeneous and converged to one of several alternative states despite identical initial conditions. 4. Differences in structure which developed among patches were the result of the assembly processes which occurred in each patch and among interconnected patches. Variance in species composition increased as a function of distance from the patches that served as entry points for invasions into the landscape. 5. The development of organization at the landscape level results from the interplay between the assembly of individual patches and the constraints imposed on each patch by invasion among patches. 6. Differences in invasion success and persistence led to the development of alternative community states.