This PhD thesis explores the effects of spatial arrangements of riparian landscape elements and food resources on community and population dynamics of small mammals within a braided section of the River Tagliamento in Italy. The main research questions addressed were: (1) Which variables affect small mammal diversity on river islands? (2) Do small mammal populations inhabiting river islands differ in their life histories compared to riparian forest populations (the ‘island syndrome’)? (3) Is there a difference in the spatial behaviour of small mammals inhabiting the riparian forest compared to those on the islands? Three rodent species were used as focal species to address these questions: Apodemus sylvaticus, A. flavicollis and A. agrarius. The expectations were that small mammal dynamics did not fit completely island biogeography and life-history models developed for oceanic islands because islands in the present study are characterised by a low degree of isolation from the surroundings, by an ephemeral nature due to periodical flooding and by a low availability of food resources for small mammals. The main findings confirm these expectations, with the three species only partially following the predictions both at community and population ecology levels. Of the three species, A. sylvaticus was the most insular and more closely followed the predictions, in particular that of the island syndrome. Small mammal diversity on the islands was affected by island area, by the flooding dynamics and by resource availability. Finally, home ranges of A. agrarius were much larger on the islands than in the riparian forest. The findings suggest that river islands in the study area are a lower-quality habitat, partly due to their ephemeral nature, but the presence of habitat heterogeneity introduced by the islands allows for the rich community of small mammals to segregate, hence increasing species diversity at a landscape level.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:695768 |
| Date | January 2016 |
| Creators | Iordan, Francesca |
| Contributors | Francis, Robert Aaron ; Mulligan, Mark ; Gurnell, Angela Mary |
| Publisher | King's College London (University of London) |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://kclpure.kcl.ac.uk/portal/en/theses/small-mammal-dynamics-within-a-natural-river-corridor-fiume-tagliamento-ne-italy(7f5c1eba-78d6-4530-935d-a1095c6fd96d).html |
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