BRANTA — Eric Le Tortorec
Reproductive Success Responses To Habitat Fragmentation In Eurasian Treecreepers
Institution: University of Turku, Finland
Supervisors: Harri Hakkarainen, Samuli Helle, Niina Kïyhkö
Details: PhD 2013 (Completed)
Address: Department of Biology, Section of Ecology, 20014 University of Turku, Finland (Sept 2013) Email
Subject Keywords: GIS, Remote sensing, Change, Landsat, Certhia familiaris
Species Keywords: Eurasian treecreepers, Certhia familiaris
Thesis Online here
Human-caused habitat fragmentation is a key driver of species loss worldwide, and has been shown to affect a wide range of organisms including mammals, invertebrates and plants, although most studies have been conducted with birds. Previous individual-level studies on the effects of habitat fragmentation in birds have demonstrated the negative consequences on food supply, survival and reproductive success. Although a great amount of information regarding the effects of habitat fragmentation on individuals and populations is available there is still a lack of understanding of the pathways through which these effects act.
In this PhD project I have used the Eurasian Treecreeper (Certhia familiaris) to study how the loss and fragmentation of old forest affects nestling growth, adult condition and reproductive success at the individual level. The Treecreeper is a small area-sensitive arboreal passerine that shows a clear preference for old-growth forests and readily accepts specially designed nest boxes, which makes it a good study organism for studying the effects of habitat fragmentation. The data used in this project were collected between 1999 and 2006 from Treecreepers nesting in nest boxes in a study area covering a total area of 1150km2 in Central Finland. Landscape metrics describing habitat loss and fragmentation were calculated at both the territory and landscape scales.
Overall the results of this PhD project showed that habitat fragmentation mainly affects Treecreepers at the nest selection stage - those territories with the most habitat loss and fragmentation were not occupied. Therefore occupied territories were of sufficiently high quality that the effects of habitat fragmentation were not readily detectable as reduced nestling and adult condition and reproductive success. Interestingly, two of the studies in this thesis showed that at the landscape scale increasing amounts of forests were associated with decreased numbers of fledged offspring, which highlights the importance of using multi-scale analyses when studying the effects of habitat fragmentation on individuals.