Variazioni temporali nella struttura di vertebratocenosi nei Monti della Tolfa: influenza di cambiamenti climatici e impatto antropico.
The study of the dietary changes which have intervened over the years in generalist and opportunist predators may provide useful information on the temporal modifications of their prey communities, especially under a climate change scenario. In this study, we analyzed the quantitative changes in the...
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| Other Authors: | , , |
| Format: | Doctoral or Postdoctoral Thesis |
| Language: | Italian |
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Università degli Studi di Roma "La Sapienza"
2013
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| Subjects: | |
| Online Access: | http://hdl.handle.net/11573/916772 http://hdl.handle.net/10805/2175 |
| Summary: | The study of the dietary changes which have intervened over the years in generalist and opportunist predators may provide useful information on the temporal modifications of their prey communities, especially under a climate change scenario. In this study, we analyzed the quantitative changes in the small mammals portion of the diet of two generalist and opportunist predators, the Barn owl (Tyto alba) and the Asp viper (Vipera aspis), in a forest zone in central Italy, for the period respectively 1987-2010 and 1975-2008. Concerning the Barn Owl, studied through the analysis of its pellets, there was no apparent change over the years, except for an increasing trend of syn-anthropic species Mus musculus domesticus and Rattus rattus. Similarly Microtus savii, a typical rodent of agroteriocoenoses, doesn’t show significant variations over the years. However, since I did not obtain a longitudinal long-term dataset on Barn owl pellets, I tested the methodology through a longitudinal sampling (for 30 years) at two Spanish areas. In this case it was possible to record a significant increase in two termoxerofilic species, Mus spretus and Crocidura russula, during the period analyzed. However, correlating this increase with thermopluviometric data for the same Iberian areas there wasn’t a significant correlation. As regards the analysis of the diet of the Viper, this issue was also studied through the analysis of ingesta, for a longitudinal period of 20 years. Among the various taxa eaten by vipers, only two showed significantly consistent trends over the years, with Myodes glareolus increasing and Sorex spp. declining in the viper diet. Despite being temperate-zone forest-associated species, hence likely adversed by global warming, Sorex spp. and Myodes glareolus showed opposite trends over the years, thus suggesting that such trends may reflect more local scale perturbations (local forest overgrowth and diminution of logging). I also found a significantly positive relationship between small mammals abundance in the ... |
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