Part A-Experimental design: Controlling variables Damschen and her team were able to conductamanipulative experiment to test their hypothesis Connecting patches plant species richness in the patches. They cleared 30 large patches of 1orest at the Savannah River Site 50that the patches a started with a plant species richness of zero. Then they set up different treatments to simulate connectedness and lack of connectedness. They used strips of cleared land, called corridors, to connect patches. To control for the many variables present in a field experiment, it was critical that the experiment was designed properly. If the patches differed in more than the presence or absence of a corridor, it would not be properly controlled, and they could not be certain if results were caused by the corrido or some other variabl To test the hypothesis that comidors promote plant species richness, they created two types of patches, shown below. One patch, caled the connected patch, was connected to a central patch by a 150 m comidor A second patch, called the unconnected winged patch, was 150 m from the central patch but not connected by a comidor. Wing 150 m 000 m Comidor 150 m Connected Central Unconnected patch "winged" patch patch 25 m Adapted from Damschen, E et al. 2006. Comid Plant species Richn at Large scales. Science 313, 12B4-1286. This design enabled them to control for several factors. 1. The total area ofthe patch plus the comidor, or the patch plus the wings was the same. 2. The total amount of edge (perimeter of each patch) was similar betweenthe two treatments. 3 Both patch types were the same distance from the central patch. Below are 4 examples of ways Damschen and her colleagues could have designed their experiment. Identify what is wrong with each design.