Study sites

Three urban-industrial sites were chosen for monitoring the development of soils and the dynamics of plant and animal populations. All study sites are located within the core of the urban-industrial agglomeration of the Ruhr. All were used formerly as coal mines and are now integrated into the Projekt Industriewald Ruhrgebiet, which ensures the future existence of the sites. The first is Zollverein coal mine (20 ha), located within the city of Essen. The other sites are within the city of Gelsenkirchen: the Rheinelbe coal mine (42 ha) and the Alma coal mine (26 ha). The area of each plot is 0.1 ha, including a subplot for vegetation relevees (100 m2). The other analyses of vegetation structure, soil profiles and faunistic sam­pling were done outside of this subplot. Table 1 gives further information on the studied plots. For five plots, the parent material for soil genesis was hard coal-mining spoil from a depth of more than 1,000 m; the ecosystem dynamics on the remaining plot started with building rubble.

Table 1. Location of the permanent plots (0.1 ha) on three sites (former Alma, Rheinelbe and Zollverein coal mines). The ecological features describe site and vegetation characteristics at the beginning of the investigation in 1999

Successional stage

Alma (A)

Rheinelbe (R)

Zollverein (Z)

Pioneer stage (P)

Plot PA: recent hard coal-mining spoil with bare ground

Plot PZ: hard coal-mining spoil with sparse vege­tation

Shrub stage (S)

Plot SA: rubble with tall herbs and shrubs

Plot SR: hard coal-mining spoil with 5- to 10- year-old birch stand

Woodland stage

Plot WR: minine

Plot WZ: minine

(W)

spoil dominated by 40- to 50-year – old birch

spoil dominated by 80- to 90-year – old planted black locust

Table 2. Methodological approaches for analysing chemical, physical, microbi­ological and zoological soil properties in the soil profiles with information on the planned repetitions (repetition intervals in brackets)

Parameters

Method

Chemical (10 years)

pH value

In 0.01 M CaCl2

Electric conductivity

Electrode in 1:5 soil-to-water suspension

Carbonate content

Volumetric CO2 measurement with Scheibler – Finkener alkalimeter

Cation exchange capacity (CEC)

Method of Mehlich (Schlichting et al. 1995 )

Plant-available phosphate and potassium

By VDLUFA method (Hofmann 1991)

Plant-available magnesium

By calcium-chloride extraction

Content of heavy metals

Aqua regia-extractable contents of Cd, Zn, Pb, Cu, Ni

Pedogenous iron and manga-

Extraction with dithionit (Mehra and Jackson

nese oxides

1960); extraction with NH4 oxalate according to Tamm/Schwertmann (Schlichting et al. 1995)

Physical (10 years)

Soil-water content

Gravimetric

Gravimetric measurement of 500-cm3 soil sam­ples

Подпись: Table 2. (cont.) Bulk density Humus content Microbiological (3 years) Soil respiration Substrate-induced respiration Microbial biomass Подпись:Combustion residue loss (gravimetric)

Oxygen uptake, a Sapromat (Schinner et al. 1993) Oxygen uptake after addition of glucose, Sapro­mat (Schinner et al. 1993)

Indirect estimation by conversion factor from substrate-induced respiration at 22°C (Anderson and Domsch 1978; Alef 1991)

With the substrate TTC incubated for 24 h; modi­fied from Thalmann (Schinner et al. 1993) Litterbag method (Bocock and Gilbert 1957; Dunger and Fiedler 1989; Alef 1991)

Zoological (5 years)

Lumbricidae: species richness formalin expulsion/hand picking and abundance

Enchytraeidae: species rich – Wet extraction according (Dunger and Fiedler ness and abundance 1989)

Springtails (Collembola): de – Dry extraction by Berlese-Tullgren method

termination to genus level and

abundance