They act as apt metaphors for urban decay; from her sculpture of the bankrupt and perpetually recovering city of Detroit, to the skyline of the overwhelmingly expensive city of London, the "melting" processes that take place look almost deliberate in their own natural decompositions.
Locally, urbanization might affect decomposition within urban boundaries.
To determine differences in water content, pH, and salt concentration between urban and periurban decomposition sites, soil cores were taken at all decomposition sites at six dates during the course of the litterbag experiment.
Mean temperatures, water contents, pH, and electrical conductivities measured at urban and periurban decomposition sites were tested for significant differences via t-tests.
And in accordance to results at urban and periurban decomposition sites, litter of urban origin decomposed faster than litter of periurban origin (94% ± 1% and 92% ± 1% mass loss, respectively, p ≤ 0.05) (Figure 4a).
To determine soil temperatures at urban and periurban decomposition sites during the reciprocal litter transplant experiment, iButtons® (accuracy of ±0.5°C and resolution of 0.0625°C; DS1922L-F5#, MaxIntegratedted, San Jose, CA, USA) were placed in plastic zipper bags and placed alongside the buried litterbags (see above) at 0- to 5-cm depth.
We conclude that the level of urbanization affects decomposition indirectly through alterations in leaf litter quality even over short urban to periurban distances.
Since Populus showed a very pronounced contrast in decomposition between urban and periurban litter originating from urban habitats in the climate chamber incubation experiment (see below), a Mann–Whitney test was conducted for differences between mass losses of all litter with regard to origin excluding Populus data.
Further, the study (2) examines direct influences of decomposition sites (urban vs. periurban) on mass loss by comparing decomposition at urban and periurban sites including field measurements of the site conditions.
EC [μS cm−1] 107 (±5) 165 (±14) <0.05 Measured soil parameters (min. and max. for pH) over the course of the experiment at the periurban (n = 15) and urban (n = 15) decomposition sites with the respective t-test p values (n.s., not significant).
