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1

Relative roles of density and rainfall on the short-term regulation of Mediterranean wood mouse Apodemus sylvaticus populations

100%
Diaz M., Torre I., Arrizabalaga A.
Acta Theriologica
|
2010
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tom 55
|
nr 3
251-260
This study aims to quantify the relative effects of density-dependent (feedback structure) and density-independent climatic factors (rainfall) in regulating the short-term population dynamics of wood mice Apodemus sylvaticus Linnaeus, 1758 in three Mediterranean forest plots. Rainfall and density explained additively 62% of variation in population growth rates (38 and 24%, respectively), with no differences among study plots. Population growth rate was positive during autumn–winter and negative during spring–summer during a 2.5-year period. Population rate of change was negatively affected by wood mouse density during the normal breeding season of Mediterranean mice (autumn–winter) but not outside it. Growth rate was positively affected by the cumulative amount of rainfall three months before the normal breeding season, but not during it. Female breeding activity and recruitment did not differ among plots, and was not affected by density or rainfall. However, recruitment was positively affected by density and, marginally, by rainfall. Our results suggest that intraspecific competition (density-dependence) and food availability (rainfall) are equally important factors driving wood mouse population dynamics in Mediterranean forests. Mechanisms underlying density-dependence during the breeding season seemed to be based on food-mediated survival rather than on behaviourally-mediated reproduction. Taken together, these results indicate a high sensitivity of marginal Mediterranean wood mouse populations to the expected climate changes in the Mediterranean region.
2

Additive effects of climate and vegetation structure on the altitudinal distribution of greater white-toothed shrews Crocidura russula in a Mediterranean mountain range

100%
Torre I., Diaz M., Arrizabalaga A.
Acta Theriologica
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2014
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tom 59
|
nr 1
Environmental variation along geographic gradients determines the distribution of animals and plants trough both direct and indirect effects. We analyze the relative contribution of climate and vegetation structure variations along a Mediterranean altitude gradient on the patterns of abundance and occurrence of the greater white-toothed shrew Crocidura russula, a generalist small mammal whose distribution is constrained by cold conditions. Sampling was performed from February 1995 to July 1997 on nine plots covering a wide altitudinal gradient (540–1550 m a.s.l.). Structural equation models for the direct and indirect effects of climate and vegetation on shrew density and occupancy rates showed a stronger effect of vegetation structure (53 %) than direct climate effects (38 %) on shrew distribution. Shrews were more abundant in the warmer lowland sites, but were able to colonize highland cold areas by selecting habitats with well-developed understory vegetation (low shrubs or bracken). Vegetation effects were additive to climatic restrictions, seemingly providing more favorable microclimatic, and presumably food, conditions under shrub cover. Results indicate that predictions of range changes for shrews under climate change scenarios may underestimate expected range expansions under the current conditions of general land abandonment and shrub encroachment.
3
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Differential anti-insect activity of natural products isolated from Dodonaea viscosa Jacq. (Sapindaceae)

64%
Diaz M., Diaz C. E., Alvares R. G., Gonzalez A., Castillo L., Gonzalez-Coloma A., Seoane G., Rossini C.
Journal of Plant Protection Research
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2015
|
tom 55
|
nr 2
Botanical biopesticides constitute an important tool for Integrated Pest Management practices. Uruguay has a great potential for developing botanical biopesticides from its abundant native flora. Dodonaea viscosa Jacq. is a native Sapindaceae that in preliminary studies was shown to possess a potential deterrent activity against insect models. In this work, ethanolic extracts of the leaves of this species were studied. Bioguided fractionation and supercritical fluid extraction led to the isolation of active compounds. For that purpose four insect models were used: Epilachna paenulata, Spodoptera littoralis, Myzus persicae, and Rhopalosiphum padi, which are pests of crops of economic importance. Lupeol, stigmasterol, stigmast-7-en-3-ol, and a labdane diterpene were isolated and showed differential activity against the models.
4

Edge effects and patterns of winter abundance of wood mice Apodemus sylvaticus in Spanish fragmented forests

64%
Garcia F. J., Diaz M., De Alba J. M., Alonso C. L., Carbonell R., De Carrion M. L., Monedero C., Santos T.
Acta Theriologica
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1998
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tom 43
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nr 3
This paper analyzes the winter pattern of abundance of wood mice Apodemus sylvaticus (Linnaeus, 1758) as related to the distance from forest edges in two Spanish fragmented forests. Mouse abundance was measured by means of pitfall traps located at a range of distances from forest edges in large forests, in small woodiots, and in the agricultural matrix surrounding both woodiots and forests (both close to forest edges and far from them). Mouse abundances were larger in forests than in croplands, and tended to become larger in woodiots and forest edges as compared to forest interior, and close to woodland as compared to far from it in the croplands surrounding forests. Overall, wood mouse distribution appeared as clearly affected by edge effects, the species behaving as a typical ecotonic, soft-edge species, as expected by its generalist habitat selection behaviour. The implications of this pattern of winter distribution are discussed in relation to the well-documented increased abundances of wood mice in fragmented forests, as well as to the potential negative effects of wood mouse populations on forest species through predation and exploitative competition.
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