Field of Science

Experimental design

Field work is generally very time consuming, but for many of us that is our laboratory. This week the effort is to add a new wrinkle to a long term experiment. Central to all of this is a hemiparasitic plant, green and photosynthetic, but an obligate parasite on surrounding plants. So if parasitic, why be green; and if green, why be photosynthetic? Part of the answer is nutrients, particularly nitrogen, in a limited environment, which is what this hemiparasite obtains from its hosts. In the process it further limits their growth, but the additional light may improve its photosynthesis. So shade was added, nutrients were added, and the hemiparasite removed (several prior posts have bemoaned this treatment), and of course, all the possible combinations of these three treatments. After three years there have been changes, and now the invertebrate population is being sampled to see under what conditions their numbers, species diversity, and ecological roles have changed. Sounds like fun doesn't it? But sticky traps are a devil to deal with because they are really, really sticky. So soon an answer may be forthcoming. Predictions: the hemiparasite's presence with increase diversity; additional nutrients will reduce diversity. If only data weren't so hard to get, this would all be fun.

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