1. Breakdown and macroinvertebrate colonization patterns of leaf packs in impaired streams Cabrini R. 1 , Canobbio S. 1 , Sartori L. 1 , and Mezzanotte V. 1 XXI Congresso della Società Italiana di Ecologia Palermo, 5 ottobre 2011 1 Dipartimento di Scienze dell’Ambiente e del Territorio, Università degli Studi di Milano-Bicocca, Piazza della Scienza 1, 20126 Milano, Italia, email: [email_address]

2. Introduction Water Directive 2000/60/CE  “ good ” ecological status Macroinvertebrates prefer leaf litter of some species over others (Graça, 2001) Reintroduction of native vegetation  river restoration tool

3. Why leaf packs? T he contribution of shed leaves by riparian vegetation is the most important source of organic matter (Wallace et al ., 1997; Power & Dietrich, 2002) and forming leaf packs are then degraded by a combination of physical and biological processes Degradation of leaf packs Microbial activity (fungi and bacteria) Physico-chemical alteration (water flow, abrasion) Macroinvertebrate colonization (food and refuge) CPOM  FPOM Introduction

6. Material and methods Material and methods Three kind of leaves Native mix leaves: alder, oak and white hornbean Naturalized leaves: locust-tree Alien “ urban ” leaves: laurel Leaves was dried for 24 hours at 105° C to obtain standardized moisture contents.

7. The greatest differences between control and impaired sites were observed for total phosphorous and nitrogen, ammonia nitrogen, COD and E. coli Results Water Chemistry

8. Results Leaf breakdown Control group Impaired group ANOVA split-plot – Weight loss

9. ANOVA split-plot – Taxa Richness Results ANOVA split-plot – Shannon Index Macroinvertebrate assemblages Taxa richness and Shannon index shows values ​​significantly different between site gr ou p division ( variable: Quality ). Taxa richness is ​significantly different among substrate .

10. Results Macroinvertebrate assemblages Control group Impaired group Laurel Locust-tree Native mix Taxa richness

11. Results Macroinvertebrate assemblages Laurel Locust-tree Native mix Taxa richness Control group Impaired group

12. Results Macroinvertebrate assemblages Tukey HSD Test P<0,001 Laurel Locust-tree Native mix Taxa richness Control group Impaired group

13. Results Macroinvertebrate assemblages Control group Impaired group Shannon Index Laurel Locust-tree Native mix Laurel Locust-tree Native mix Taxa richness

14. Results Macroinvertebrate assemblages Control group Impaired group Laurel Locust-tree Native mix D-Shredders ANOVA split-plot – FFG-FHG

15. Results Macroinvertebrate assemblages Tukey HSD test P<0,05 Control group Impaired group Laurel Locust-tree Native mix D-Shredders ANOVA split-plot – FFG-FHG

18. Thanks for your attention!