| 1. |
- Cortazar-Chinarro, Maria, et al.
(författare)
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Association between the skin microbiome and MHC class II diversity in an amphibian
- 2024
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Ingår i: Molecular Ecology. - : John Wiley & Sons. - 0962-1083 .- 1365-294X. ; 33:1
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Tidskriftsartikel (refereegranskat)abstract
- Microbiomes play an important role in determining the ecology and behaviour of their hosts. However, questions remain pertaining to how host genetics shape microbiomes, and how microbiome composition influences host fitness. We explored the effects of geography, evolutionary history and host genetics on the skin microbiome diversity and structure in a widespread amphibian. More specifically, we examined the association between bacterial diversity and composition and the major histocompatibility complex class II exon 2 diversity in 12 moor frog (Rana arvalis) populations belonging to two geographical clusters that show signatures of past and ongoing differential selection. We found that while bacterial alpha diversity did not differ between the two clusters, MHC alleles/supertypes and genetic diversity varied considerably depending on geography and evolutionary history. Bacterial alpha diversity was positively correlated with expected MHC heterozygosity and negatively with MHC nucleotide diversity. Furthermore, bacterial community composition showed significant variation between the two geographical clusters and between specific MHC alleles/supertypes. Our findings emphasize the importance of historical demographic events on hologenomic variation and provide new insights into how immunogenetic host variability and microbial diversity may jointly influence host fitness with consequences for disease susceptibility and population persistence.
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| 2. |
- 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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| 3. |
- Montori, Albert, et al.
(författare)
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Habitat features affecting the small-scale distribution and longitudinal migration patterns of Calotriton asper in a Pre-Pyrenean population
- 2008
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Ingår i: Amphibia-Reptilia. - 0173-5373 .- 1568-5381. ; 29:3, s. 371-381
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Tidskriftsartikel (refereegranskat)abstract
- The longitudinal movements and abiotic factors that determine the distribution of Pyrenean mountain newts (males, females, amplexus and metamorphic newts) were examined in a 1500 meters segment of a Pre-Pyrenean stream. Migration of adult newts was studied by means of capture-recapture techniques in the course of one year. Our results indicate that the mean distance the newts migrated per year was less than 50 meters and the population could be considered sedentary. No significant differences in longitudinal movement patterns between the sexes were observed, and movement patterns were more or less constant over time. Habitat variables determining newt abundance was estimated by means of a GLM. Our results indicate that the number of refugia (wood debris, stones and fissures) determines the distribution of newts. Larval abundance was correlated with stream-bed structure.
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| 4. |
- 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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| 5. |
- Pujol-Buxo, Eudald, et al.
(författare)
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Growth strategies of tadpoles along the pond permanency gradient
- 2016
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Ingår i: Evolutionary Ecology. - : Springer Science and Business Media LLC. - 0269-7653 .- 1573-8477. ; 30:6, s. 1117-1132
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Tidskriftsartikel (refereegranskat)abstract
- The preference for particular features of water bodies for reproduction is one of the most important aspects of anuran ecology, affecting key aspects of both tadpole and adult life. The use by species of different habitats along the pond permanency gradient has been already studied, noting conflicting selective pressures from predation and desiccation risk. Here, we aim to discover physiological patterns related with this gradient. As a study system, we used the full anuran community of the NE Iberian Peninsula. We quantified growth rate, consumption rate, food assimilation and the proportion of energy allocated to growth, as well as gut length, for all species. Food consumption rate and growth allocation were the variables that defined tadpole growth, while food assimilation abilities and gut length seem to have a secondary or cryptic role in growth. More interestingly however, our data suggests a labile continuum of consumption-based versus allocation/assimilation-based growth strategies differentiating species. Differences among species follow predictions of adaptation to the pond permanency gradient selective pressures. Species from ephemeral ponds are more prone to use consumption-related growth tactics while species inhabiting ponds with longer hydroperiods are more efficient retaining and allocating energy into growth, although results seem partly shaped by strong interspecific competition. Physiological differences in growth and the usage of the assimilated energy could be an additional factor to understand how tadpoles adapt to the features of ponds they inhabit, as well as how they compete and coexist.
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| 6. |
- 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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| 7. |
- San Sebastian, Olatz, et al.
(författare)
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Differential trophic traits between invasive and native anuran tadpoles
- 2015
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Ingår i: Aquatic Invasions. - : Regional Euro-Asian Biological Invasions Centre Oy (REABIC). - 1798-6540 .- 1818-5487. ; 10:4, s. 475-484
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Tidskriftsartikel (refereegranskat)abstract
- How trophic resources are managed is a key factor in our understanding of the success of invasive species. In amphibians that usually occupy ephemeral ponds, the capacity to acquire resources and food selection are especially important because as a pond dries, the larval density increases and food resources are limited. Abundant and high-quality food can increase the final size and reduce the duration of development of amphibians. The aim of this work was to assess the trophic traits of tadpoles of the invasive (originally North African) anuran Discoglossus pictus compared to those of native European Epidalea calamita tadpoles under laboratory conditions. Food of two different levels of quality was supplied, and the feeding activity and food preference of the two species were analysed alone and in co-occurrence. D. pictus was capable of modifying its behaviour and food preferences; while E. calamita displayed much milder differences between treatments. Both alone and in co-occurrence with the native species, the invasive tadpoles obtained higher feeding activity values and showed a stronger preference for high-quality food. Additionally, when high densities of the two species shared food resources, the feeding activity results indicated potential displacement of the native tadpoles to low-quality resources. D. pictus thus presents trophic traits that are favourable for invasion and could limit the fitness of E. calamita when resources are limited or there is a risk of pond desiccation.
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| 8. |
- San Sebastian, Olatz, et al.
(författare)
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Trophic Strategies of a Non-Native and a Native Amphibian Species in Shared Ponds
- 2015
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:6
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Tidskriftsartikel (refereegranskat)abstract
- One of the critical factors for understanding the establishment, success and potential impact on native species of an introduced species is a thorough knowledge of how these species manage trophic resources. Two main trophic strategies for resource acquisition have been described: competition and opportunism. In the present study our objective was to identify the main trophic strategies of the non-native amphibian Discoglossus pictus and its potential trophic impact on the native amphibian Bufo calamita. We determine whether D. pictus exploits similar trophic resources to those exploited by the native B. calamita (competition hypothesis) or alternative resources (opportunistic hypothesis). To this end, we analyzed the stable isotope values of nitrogen and carbon in larvae of both species, in natural ponds and in controlled laboratory conditions. The similarity of the delta N-15 and delta C-13 values in the two species coupled with isotopic signal variation according to pond conditions and niche partitioning when they co-occurred indicated dietary competition. Additionally, the non-native species was located at higher levels of trophic niches than the native species and B. calamita suffered an increase in its standard ellipse area when it shared ponds with D. pictus. These results suggest niche displacement of B. calamita to non-preferred resources and greater competitive capacity of D. pictus in field conditions. Moreover, D. pictus showed a broader niche than the native species in all conditions, indicating increased capacity to exploit the diversity of resources; this may indirectly favor its invasiveness. Despite the limitations of this study (derived from potential variability in pond isotopic signals), the results support previous experimental studies. All the studies indicate that D. pictus competes with B. calamita for trophic resources with potential negative effects on the fitness of the latter.
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