| 1. |
- Garriga, Nuria, et al.
(författare)
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Are protected areas truly protected? : The impact of road traffic on vertebrate fauna
- 2012
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Ingår i: Biodiversity and Conservation. - : Springer Science and Business Media LLC. - 0960-3115 .- 1572-9710. ; 21:11, s. 2761-2774
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Tidskriftsartikel (refereegranskat)abstract
- The extension of road networks is considered one of the major factors affecting fauna survival. Roadkill has been documented widely and affects all taxonomic groups. Although roadkill is associated mainly with traffic density, some life-history traits of species and the area surrounding roads are expected to modify number of roadkills both taxonomically and geographically. Here we studied the number of roadkills of vertebrates in an extensive region in the northeastern Iberian Peninsula. We surveyed 820 km of 41 roads in two different seasons (spring and autumn), that differ in traffic intensity. In addition, we covered zones with distinct climatic characteristics and levels of protection of the surrounding habitats. Amphibians showed the highest number of roadkills whereas reptiles, birds and mammals had similar rates. General Linear Model tests showed no differences in roadkills by climatic region; however, differences in number of roadkills were linked to protection status, with the highest number of casualties in highly protected areas. Redundancy Analysis demonstrated that the number of amphibians and reptiles killed was associated with roads in highly protected areas whereas that of mammals and birds was linked to unprotected areas. Protected areas often receive many visitors, which in turn may increase wildlife casualties as a result of greater traffic density. We recommend that correction measures be taken to reduce the high number of vertebrate fauna killed along roads that cross protected areas.
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| 2. |
- Oromi, N., et al.
(författare)
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Genetic variability in geographic populations of the natterjack toad (Bufo calamita)
- 2012
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 2:8, s. 2018-2026
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Tidskriftsartikel (refereegranskat)abstract
- Across altitudinal and latitudinal gradients, the proportion of suitable habitats varies, influencing the individual dispersal that ultimately can produce differentiation among populations. The natterjack toad (Bufo calamita) is distributed across a wide geographic range that qualifies the species as interesting for a geographic analysis of its genetic variability. Five populations of B. calamita in the Sierra de Gredos (Spain) were studied in an altitudinal gradient ranging from 750 to 2270 m using microsatellite markers. In addition, we analyzed the latitudinal genetic variation in B. calamita within a global European distribution using genetic diversity parameters (mean number of alleles per locus [M-a] and expected heterozygosity [H-E]) obtained from our results and those published in the literature. The low level of genetic differentiation found between populations of B. calamita (F-st ranging from 0.0115 to 0.1018) and the decreases in genetic diversity with altitude (M-a from 13.6 to 8.3, H-E from 0.82 to 0.74) can be interpreted by the combined effects of discontinuous habitat, produced mainly by the high slopes barriers and geographic distance. In the latitudinal gradient, genetic diversity decreases from south to north as a consequence of the colonization of the species from the Pleistocene refugium. We conclude that the genetic variability in B. calamita along its wide altitudinal and latitudinal geographic distribution mainly reflects the colonization history of the species after the last glacial period.
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| 3. |
- Richter-Boix, Alex, et al.
(författare)
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Effects of the non-native amphibian species Discoglossus pictus on the recipient amphibian community : niche overlap, competition and community organization
- 2013
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Ingår i: Biological Invasions. - : Springer Science and Business Media LLC. - 1387-3547 .- 1573-1464. ; 15:4, s. 799-815
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Tidskriftsartikel (refereegranskat)abstract
- The painted frog, Discoglossus pictus, was introduced into the Iberian Peninsula 100 years ago and its distribution has steadily increased since then. We studied the effects of this non-native amphibian species on the native ones in the northeastern area of the peninsula. We compared amphibian assemblages in regions with and without D. pictus to estimate niche overlap between species. Additionally, we carried out a laboratory evaluation of the effects of competition between the non-native and the two native species with which it overlaps most commonly: Bufo calamita and Pelodytes punctatus. The presence of D. pictus larvae reduced the survival, body mass and activity of B. calamita, and increased time to metamorphosis. Furthermore, D. pictus showed the highest consumption rate while P. punctatus showed the lowest. One possible consequence of these competitive interactions is an alteration of species co-occurrence patterns in the recipient community on a regional scale. In the non-invaded area, the checkerboard score (C-score) of co-occurrence indicated that the community was structured, whereas the standardized C-score in the invaded area indicated that the community did not differ significantly from having a random structure. These results suggest that competition between native and non-native species can cause recipient communities to become less structured.
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