Small Remnants of the Rice Lake Plains Prove Important - How Many Do We Need?

Abstract

Protecting large areas has a lot of well-documented advantages over protecting small areas, but small areas, especially with regard to rare plants, can be very important. This has been known for some time (e.g., Conner and McCoy 1979). One of the best articles about the long term species retention in very small areas is that of Reznicek (1987). In some situations it is possible to analyze data to test this “small area value” hypothesis, and data on remnants of the Rice Lake Plains is available to do it. (see Catling 2008). Remnants of the plains with regionally rare and very restricted flora are known from the higher parts of the Oak Ridges moraine to the west, south and east of Rice Lake (Catling et al. 1992; Catling 2008). At least 42 relatively well-preserved and isolated remnants are known, and data on the total number of native species and number of regionally rare native species are available for 24. These remnants vary in size from 0.1 to 16.7 ha and collectively contain 257 native species of which 111 are regionally rare. A simple linear regression plot of species number and area for the 24 sites provides a trend line with sig nificance values. (Figure 1). The line suggests that as size increases the number of species tends to increase. However, the model is not significant in either case (at P = 0.05 level) and in fact is not even close to being significant (P > 0.16). In these data, speciesarea relationship is not important. It is clear that some smaller sites such as 29 (a 1.64 ha remnant in and near Goodrich-Loomis Conservation Area) contain almost as much biodiversity as much larger sites such as 12 (8.82 ha of prairies and savanna at Alderville First Nation), and a number of small sites are positioned quite high above the line. The regionally rare species have presumably been present at these small sites for more than a hundred years, since the plains were largely Small Remnants of the Rice Lake Plains Prove Important ... How Many Do We Need?