Kalibratie van Ellenbergs milieu-indicatiegetallen aan werkelijk gemeten bodemfactoren
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Series / Report no.
Open Access
Type
Report
Language
nl
Date
1996-05-31
Research Projects
Organizational Units
Journal Issue
Title
Kalibratie van Ellenbergs milieu-indicatiegetallen
aan werkelijk gemeten bodemfactoren
Translated Title
Calibration of Ellenbergs indication values on
measured soil characteristics
Published in
Abstract
Momenteel wordt een multiple stress model ontwikkeld
waarmee op nationale schaal de kans op voorkomen van plantesoorten wordt
voorspeld als gevolg van verdroging, verzuring en vermesting (SMART-MOVE).
Het model bestaat uit een bodemmodule (SMART) en een vegetatie module
(MOVE). Essentiele invoergegevens voor deze modules, zoals grondwaterpeil
en kwelflux kunnen worden berekend met bijvoorbeeld het LGM (Landelijk
Grondwater Model). Met de vegetatie-module kan de kans op voorkomen van een
soort bepaald worden aan de hand van ecologische amplitudes van de
plantesoorten. De ecologische amplitudes zijn weergegeven op een milieu-as
die weergegeven is in gemiddelde indicatie-getallen van Ellenberg per
proefvlak. In dit rapport wordt een ijking uitgevoerd van deze
semi-kwantitatieve milieu-as aan daadwerkelijk gemeten bodemfactoren zoals
de zuurgraad (pH), de grondwaterstand (GVG: gemiddelde
voorjaarsgrondwaterstand), gehalten van nutrienten (b.v. nitraat en
fosfaat- gehalten), primaire productie (gemeten in biomassa opbrengst en
stikstof-opbrengst) en het chloride gehalte. Hiervoor is behalve van de
hiervoor doorgaans toegepaste lineaire regressie analyse ook gebruik gemaakt
van non-lineaire regressie analyse met een S-vormig model als uitgangspunt.
In totaal konden bijna 7000 opnamen worden gebruikt. Voor pH, GVG, biomassa
opbrengst en stikstof opbrengst bleken de R2-waarden zodanig hoog dat
vertaling van de gemiddelde Ellenberggetallen naar gemeten waarden vrij goed
mogelijk is. Deze relaties worden gebruikt voor de koppeling tussen de
vegetatiemodule en de abiotische modules. Daarnaast dragen zij bij aan een
betere kwantificering van de betrouwbaarheid van de modeluitkomsten. Het
gemiddelde milieu-indicatiegetal van Ellenberg lijkt voor modellen zoals
SMART/MOVE een bruikbare schattingsmethode van de abiotisch
milieucondities.
A multi-stress model has been developed in the Netherlands on a national scale to forecast changes in plant species composition due to acidification, eutrophication and dessication. This model, called SMART-MOVE, consists of: a soil module (SMART2) used for calculating changes in groundwater level, pH and nutrient availability, and a vegetation module, consisting of regression equations that describe the relationships between the probability of occurrence and environmental factors. These environmental factors represent average Ellenberg indication values for pH, availability of water and nutrient availability. Salinity was also included since in large parts of the Netherlands salinity is of major importance for species composition. Essential input data for these modules, such as groundwater level and seepage flux, can be calculated with the National Groundwater Model, for example. In this study relationships were calculated between the Ellenberg indication values and the relevant soil factors: pH, average spring groundwater table, biomass production, nitrogen production, concentrations of several nutrients and chloride concentration for both terrestrial and aquatic systems. Where it was possible to use a sigmoid model, to cope with the original ordinal and limited scale of indication values, the explained variance increased by 5-10%. In the regression analyses, almost 7000 vegetation releves from a variety of ecosystems could be used, satisfying relationships with Ellenberg values were found for pH, average spring groundwater table and biomass and nitrogen production. These relationships are used to connect the soil module with the vegetation module and quantify the confidence of the model outcomes. Average Ellenberg indication values can be concluded to be succesful as estimates for the abiotic conditions in models like SMART-MOVE.
A multi-stress model has been developed in the Netherlands on a national scale to forecast changes in plant species composition due to acidification, eutrophication and dessication. This model, called SMART-MOVE, consists of: a soil module (SMART2) used for calculating changes in groundwater level, pH and nutrient availability, and a vegetation module, consisting of regression equations that describe the relationships between the probability of occurrence and environmental factors. These environmental factors represent average Ellenberg indication values for pH, availability of water and nutrient availability. Salinity was also included since in large parts of the Netherlands salinity is of major importance for species composition. Essential input data for these modules, such as groundwater level and seepage flux, can be calculated with the National Groundwater Model, for example. In this study relationships were calculated between the Ellenberg indication values and the relevant soil factors: pH, average spring groundwater table, biomass production, nitrogen production, concentrations of several nutrients and chloride concentration for both terrestrial and aquatic systems. Where it was possible to use a sigmoid model, to cope with the original ordinal and limited scale of indication values, the explained variance increased by 5-10%. In the regression analyses, almost 7000 vegetation releves from a variety of ecosystems could be used, satisfying relationships with Ellenberg values were found for pH, average spring groundwater table and biomass and nitrogen production. These relationships are used to connect the soil module with the vegetation module and quantify the confidence of the model outcomes. Average Ellenberg indication values can be concluded to be succesful as estimates for the abiotic conditions in models like SMART-MOVE.
Description
Publisher
Sponsors
DGM/B
DGM/DWL