Small-scale habitat complexity of artificial turf influences the development of associated invertebrate assemblages

- Initial substrata complexity manipulated using artificial turf
- Unique responses of sessile and mobile biota to initial substrata complexity
- Sessile and mobile assemblage composition unrelated at a finer scale

Ecosystem engineers can influence biodiversity by enhancing complexity, and modifying the availability of resources. Understanding the mechanisms by which ecosystem engineers shape biodiversity is central to the concept of 'ecological engineering' of anthropogenic structures to enhance biodiversity. Here the presence and complexity of artificial turf was manipulated on an artificial structure to test the hypothesis that the colonisation of sessile invertebrates and mobile epibiota would vary with habitat complexity. Both sessile and mobile assemblage compositions differed according to the presence of artificial turf, and its complexity. Sessile invertebrates occupied greater proportions of available space on topographically simple 'blank' surfaces or low complexity artificial turf than those with high complexity turf, whereas mobile taxa were generally more abundant on the turf. However, the mobile assemblage was unrelated to the sessile assemblage when examined within each level of initial substrata complexity. Contrary to the increasing number of studies demonstrating nested hierarchical relationships between co-occurring ecosystem engineers, this study provides an example of an ecosystem engineer mimic (artificial turf) leading to the formation of habitat mosaics at small scales. The introduction of complex substrata to otherwise topographically simple artificial structures is a promising means of actively influencing assemblage composition.