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DDI_119.fm Page 5 Thursday, December 27, 2001 10:00 AM

Mammals from Mediterranean islands 5

Oryctolagus cuniculus
Genetta genetta
Microtus savii
Rattus rattus
Ovis orientalis
Erinaceus europaeus
Apodemus sylvaticus
Mustela nivalis
Crocidura russula
Dama dama
Cervus elaphus
Vulpes vulpes
Sus scrofa
Apodemus flavicollis
Capra aegrarus
Lepus capensis
Eliomys quercinus
Myoxus glis
Meles meles
Mus spretus
Mus domesticus
Muscardinus avellanarius
Lepus europaeus
Acomys minous
Martes martes
Lepus corsicanus
Martes foina
Canis aureus
Lutra lutra
Crocidura suaveolens
Felis silvestris
2 1 0 –1 –2
Residuals of mammal density

Fig. 2 Residuals of mammal density corrected for mammal body mass and phylogeny using the eigenvectors
method (see Material and methods).

less significant using independent contrasts (OLS
Density and island area size
slope = – 0.52 ± 0.24, r = 0.38, P = 0.012).
Using the eigenvector method, we found a We controlled the contrasts in host density for
phylogenetic effect for the relationship between the contrasts in body mass by using residuals of
density and body size, as depicted by linear the linear regression between the two variables.
correlation between these traits and the two We found a significant negative relationship
first eigenvectors of the phylogenetic matrix between the area size of islands and the residuals
(Table 2). The slope of the partial regression of host density using independent contrasts
(–0.51 ± 0.11) was not significantly different to (Fig. 3, P = 0.024). This relationship was signi-
those obtained by the independent contrasts ficant using cross species values (r = – 0.439,
method. P = 0.015). Using the eigenvectors method, a
The residuals of density, corrected for the similar and significant relationship was found
two first eigenvectors and body mass, are given between the residuals of density (Fig. 2) and the
on Fig. 2. The mammal species with high area of island (r = – 0.406; P = 0.023). We found
residuals values are then hypothesized to have no effect of geographical distance on residuals of
high abilities to maintain themselves in small host density using independent comparisons
islands. (P = 0.09).
© 2002 Blackwell Science Ltd, Diversity and Distributions, 8, 1–9