Response Curves for plants species and vegetation types as a function of soil characteristics

Select a dataset in this screen.

The top of the screen displays four choices:

− "Home"		takes you back to this screen so that you can select another dataset;
− "1 species"		displays a single species response curve in a single frame at full size;
− "1 species 4 df"		displays response curves of 1 species for 4 different degrees of freedom in 4 separate frames;
− "4 species"		displays the response curves of 4 different species in 4 separate frames.

On the left you can choose one (or more) species for which response curves are displayed, as well as degrees of freedom for the fitted penalized splines. This will display the fitted response curve in black as well as the 95% bootstrap interval in red for the fitted curve, see the Note below. The blue dots display the observed probabilities on an equidistant grid. These were obtained by first dividing the (transformed) abiotic values into 50 intervals. Then for every interval the observed probability was calculated by dividing the number of relevés at which the species was present by the total number of relevés in that interval. The size and colour of the blue dots depends on the number of relevés in the interval. Small dark blue dots represent few relevés, big light blue dots represent large numbers of relevés; this is explained by means of the "Symbol Definition Rawdata" below the species information in the "1 species" menu.
You can also use the species translator on top of the screen to select a species for which the response curve must be displayed. In the "4 species" menu this will only change the upper left species response curve.
The scale of the Y-axis of the graphs can be modified by means of the "Y" radio buttons.

In the "1 species" and "1 species 4df " menus species information is displayed on the left. This includes:

− "Npresent"		the number of sites at which the species was present AND for which the abiotic value was available;
− "Mean Data"		the mean of the abiotic values of all the relevés where that species is present;
− "Median Data"		the median of the abiotic values of all the relevés where that species is present;
− "Sd Data"		the standard deviation of the abiotic values of all the relevés where that species is present;
− "80% Data"		the 80% interval of the abiotic values of all the relevés where that species is present. another percentage can be choosen at the top right of the page. Only intervals which are obtained by interpolation are given. So when a species is only present at say 39 sites, the 95% interval and higher are not given;
− "Df Curve"		The degrees of freedom for which the Curve Mean/Median/Sd/80% information is given. The best degrees of freedom is given in parenthesis. The best df was obtained by backward deviance testing: the number of degrees of freedom of the penalized spline was decreased one at a time, from 5 to 4, 3 and 2, and was stopped when the resulting decrease in fit was significant at the 1% level as judged by a deviance test.
− "Mean Curve"		the mean of the species response curve; this is calculated by viewing the response curve as a probability density;
− "Median Curve"		the median of the species response curve; this is calculated by viewing the response curve as a probability density;
− "Sd Curve"		the standard deviation of the species response curve; this is calculated by viewing the response curve as a probability density;
− "80% Curve"		the interval of abiotic values which covers 80% of the area under the species response curve; another percentage can be choosen at the top right of the page;
− "Analysis of deviance"		Detailed analysis of deviance with deviance contribution and corresponding p-value when degrees of freedom from 1 to 10 are subsequently added to the spline. This can be used to select different degrees of freedom than according to the "best df" method.

The Curve (or Data) interval and location are displayed in the graph by means of green arrows and accompanying numbers. The interval and location can be changed by using the picklists on the top right of the screen.

Website and spline methodology by Paul W. Goedhart (Biometris, Wageningen UR)

Species response curves for various characteristics	Download data summary	Download curve summary

pH species response curves for associations	Download data summary	Download curve summary

Species response curves for associations for reconstructed pH	Download data summary	Download curve summary

Response Curves for plants species and vegetation types as a function of soil characteristics

This website accompanies the following paper:

How to use this website, see also Report