Impact of soil compaction on soil biodiversity - does it matter in urban context?

Soil invertebrates are poorly studied in an urban context. Here we examine soil compaction in an urban environment, focusing on its persistence and its impact on biodiversity. This is achieved by studying a sensitive taxon, the collembolan (springtails). Soil core samples were taken in different location of a residential neighbourhood under construction, and collembolan species were extracted using a Berlese-Tullgren funnel. Soil compaction was determined by measuring bulk density. We documented soil compaction, ranging from 1 g/cm3 to 1.6 g/cm3. While collembolans are normally affected by compaction, such an effect was not observed in terms of species diversity, which remains relatively constant under all compaction levels. However, compaction was correlated with differences in the structure of collembolan communities. Indeed, we were able to discriminate different levels of compaction using collembolan community data alone. Moreover, this study confirms that compaction decreases with time. However, differences in species community structure can be observed one year after the end of the disturbance. Finally, we provide some insights into the reality of soil compaction in an urban environment, and highlight that the classical biodiversity indices may be insufficient for assessing the impact of an environmental disturbance, and that more detailed analyses at the community level may be very useful, or even indispensable.