Tom's Blog

Monday, July 4, 2011

Savanna species diversity

This is the time of the year when one can get a good idea of the species diversity of a prairie or savanna. Most of the early-blooming species are still around (forming seeds) and the late-blooming species have made substantial vegetative populations. And there are lots of species flowering at present.

We have been keeping notes on the prairie and savanna species diversity since 1998, and since 2002 I have attempted to record every species present in each management unit. The data for the years 2002 through 2008 are extensive, and have been analyzed carefully. Although the analysis is a winter project, the utility becomes evident in the summer.

I made an Excel table that lists every species present in each of the savanna management units. Today (4th of July) I found the time to convert this table into a PDF that could be downloaded by those interested in savanna species diversity.

Download the table

These data can be analyzed in a number of different ways, but what I chose to do here was to sort by C value (Coefficient of Conservatism), since this put the most interesting species at the top of the table.

There are some species missing from this table, including a few new ones discovered since 2008. But even so, there are 238 species in this table.

One value of this table is that because it locates each species by management unit, it shows which species are really common, and which are fairly rare. At least part of the variability between units is due to canopy cover. Some of the units have lots more open canopies than others, which leads to more area where "prairie-like" species can develop.

Comparisons of canopy cover in different units can be found at this link.

As I have noted elsewhere, the species diversity in a savanna is lots higher than in either a prairie or woodland.



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