Multiple trophic levels in UV-B assessments - completing the ecosystem

While one can find ample examples in the literature that ambient and enhanced levels of UV-B do not have detectable effects on various plant and litter parameters, this should not be taken as a verdict that UV-B has no effect on other, as yet unstudied parameters in a system, or on any parameters in other systems. Furthermore, many plant species are responsive to ambient UV-B, as well as supplemental UV-B, although total biomass production does not appear to be compromised by the latter. Much of the UV-B research to date has focused on plant performance, largely because of concerns about ozone depletion effects on agricultural productivity. More research is now needed that focuses on UV-B effects over multiple trophic levels, and over longer time frames, if we are to understand how UV-B levels influence plant performance, as well as how ecosystem processes feedback to primary producers. While many of the UV-B effects detected to date appear subtle, and some researchers may have concluded that changing UV-B levels are of little consequence to plant performance, ecology has taught us that seemingly small changes in one process might ultimately have large effects at other levels of organization, and have the potential to develop feedbacks that are initially difficult to envision. The work by Searles et al. (2001b) shows us that UV-B can have significant effects on other trophic levels, and that our existing UV-B paradigm is not robust enough to predict such effects.