The time scale of many ecological processes spans decades and centuries--much longer than the lifetime of a researcher, let alone the duration of the average research grant. For instance, populations of organisms fluctuate over long periods of time, yet useful data generally are available in only a few instances.
In the mid-19th century, the Park Grass Experiment was initiated at the Rothamsted Experimental Station in the United Kingdom. Silvertown et al. have taken advantage of the documented history of fertilizer treatments in this set of grassland plots and the accompanying censuses of vegetation in order to examine the long-term population trends of plant species in relation to their genetic diversity. Species showing outbreak behavior--increases in abundance followed by decreases--had lower genetic diversity (due to inbreeding) and were thus unable to sustain their numerical expansion in comparison to persistent species that showed more stable population dynamics. The results suggest that limitation of local adaptability (to new habitats) by inbreeding may increase the extinction risk of species. -- AMS
Am. Nat. 160, 409 (2002).
