Books by Xavier Santos Santiró
This book gives an excellent overview of what is and has been investigated within this species al... more This book gives an excellent overview of what is and has been investigated within this species along a significant part of its huge range.
Papers by Xavier Santos Santiró
El Jebel Sirwa es un macizo montanoso de origen volcanico localizado entre las cordilleras del Al... more El Jebel Sirwa es un macizo montanoso de origen volcanico localizado entre las cordilleras del Alto Atlas y Anti-Atlas en Marruecos, y representa el limite sur del piso bioclimatico oromediterraneo en la cuenca del Mediterraneo. En esta nota se detallan las observaciones de 10 especies de reptiles mediterraneos para la zona norte del macizo, haciendo hincapie en su variacion altitudinal. Se cita por primera vez en el macizo la serpiente "Hemorrhois hippocrepis" y se hace una serie de consideraciones sobre el estado de conservacion de "Vipera latastei-monticola" en el mismo.
A la conca mediterrania, els incendis han desenvolupat un paper fonamental en l'estructuracio... more A la conca mediterrania, els incendis han desenvolupat un paper fonamental en l'estructuracio del paisatge i en la composicio de les comunitats d'organismes. En el futur, s'espera que aquest tipus de pertorbacio augmenti en extensio i frequencia, un fet que pot afectar el manteniment de la diversitat en els espais naturals mediterranis. En el present treball, s'ha analitzat la resposta dels coleopters de vegetacio a l'impacte d'un incendi forestal produit l'agost del 2003 en el Parc Natural de Sant Llorenc del Munt i l'Obac. La primavera del 2007 es va realitzar un mostreig amb manega entomologica en un total de 24 estacions de mostreig, que comprenen una zona control (no cremada) i quatre zones cremades amb diferent gestio postincendi. S'han fet mesures de diversitat alfa (indexs de Margalef, d'uniformitat i de Simpson) i gamma (nombre total d'especies en la zona d'estudi), aixi com analisis multivariants (analisis de components princ...
TURKISH JOURNAL OF ZOOLOGY, 2018
Changes in habitat structure are the main driving forces for responses of animal assemblages to f... more Changes in habitat structure are the main driving forces for responses of animal assemblages to fire. According to the disturbance theory, generalist species are expected to outperform specialists in variable environments. Thus, we hypothesized that omnivorous and polyphagous species will become more abundant in unstable postfire successional vegetation, whereas monophagous (specialists), due to their strong dependence on host plants, are expected to respond according to the responses of plant hosts. We compared the responses of true bug (Heteroptera) assemblages in stable (unburnt) versus unstable (postfire successional) environments as this group shows a high diversity of feeding strategies. Redundancy analysis fitted our hypothesis as omnivorous and polyphagous bugs responded positively to fire whereas oligophagous bugs did not. Thus, the most generalized bugs in terms of diet were found in disturbed (burnt) habitats whereas specialized bugs were found in undisturbed (unburnt) habitats. Moreover, the most specialized bugs (monophagous species) responded to fire in accordance to the responses of their specific host plants. Although based on small bipartite networks, the lower modularity in burnt sites corresponded to a scenario of lower segregation of plant resources and fits the higher presence of generalist bugs in these sites. Our results suggest that plant-bug trophic interactions shape the response of Heteroptera to fire, and this response seems to be mediated by the degree of feeding specialization.
Contributions to Zoology, 2012
Land-use change is considered the main disturbance in landscape structure and composition, direct... more Land-use change is considered the main disturbance in landscape structure and composition, directly affecting faunal distribution and species richness worldwide. Wildfires and natural reforestation alter habitat structure in terms of vegetation cover and also in soil composition and moisture; these processes hence trigger habitat transformations that act as opposing forces at small spatial scales. We have explored the contrasting effects of wildfires and natural reforestation on two land-snail species of the genus Xerocrassa, which are endemic in the western Mediterranean. Snails were sampled in pine and Holm oak forest, stony bare slopes and burnt sites. Both species followed a similar pattern: they were present in more than 75% of the stony bare slope sites and around 50% of the burnt sites, but were almost absent in Holm oak forests. The comparison of aerial photographs from 1956 and 2003 showed that stony bare slopes were significantly larger in 1956, this indicating that the na...
Zoologischer Anzeiger, 2017
Ecological diversification on islands typically results in divergence of ecological niches. As di... more Ecological diversification on islands typically results in divergence of ecological niches. As diet is a major component of species niches, we hypothesize that sister species within island monophyletic groups diversify in their dietary preferences. We have examined this hypothesis in two Haemodracon and four Hemidactylus species endemic reptiles of from Socotra Island (Yemen), corresponding to two independent colonization events. Convergence i.e., similar dietary patterns of phylogenetically unrelated species, was also examined. Trophic niches were studied by the analysis of carbon and nitrogen stable isotopes combined with faecal samples. We collected tail tips (for isotopes) and faecal pellets during two visits in 2013 and 2014 to Socotra. Specific trophic niche widths inferred from stable isotopes were estimated from ellipse-based metrics, whereas interspecific differences were compared by linear mixed models and examined in a phylogenetic framework. From faecal samples, diet variation among species was quantified by the Bray-Curtis index. Isotope and dietary interspecific divergence was compared with Mantel tests. For both isotopes, models detected interspecific differences between sister species i.e., trophic niche divergence and also interspecific similarities of distant lineages that use similar microhabitats i.e., ecological convergence. We did not find any phylogenetic signal neither in the interspecific differences in δ 13 C nor in δ 15 N isotopic values; thus species phylogenetically more closely related did not have more similar isotopic niches. The Mantel test demonstrated similar interspecific divergence using isotopes and faecal samples. In a phylogenetic context, trophic-niche interspecific comparisons highlight some mechanisms that are driving ecological diversification and speciation of Socotra Island.
Basic and Applied Herpetology, 2012
Amphibians living in streams are often subjected to spates. These waterfloods are the main cause ... more Amphibians living in streams are often subjected to spates. These waterfloods are the main cause of organism drift and mortality, and these effects can be confounded with population decline. Discrimination between population decline and natural fluctuations in unpredictable habitats requires the study of population dynamics through monitoring and long data series. We conducted a 21-year demographic field survey of a newt (Calotriton asper) population in the eastern Pyrenees. Our results indicate that the adult population showed high fluctuations in response to heavy rainfall. Maximal rainfall in 24 h (higher than 50 l / m 2) caused population decreases as a result of catastrophic drift. The larval population also decreased after heavy rainfall. The data from this survey show that the population recovered three years after catastrophic drift. Subadult C. asper show terrestrial activity and are not affected by waterfloods. Interannual dynamics revealed that the stock of subadults allowed for rapid population recovery after catastrophic drift episodes. Flooding produced higher mortality when it occurred during winter than during the active cycle of newts. This long-term study provides new insights into the survival strategies displayed by newts in response to extreme stream environments.
Ecosystems, 2017
In recent decades, fires in Mediterranean Europe have become larger and more frequent. This trend... more In recent decades, fires in Mediterranean Europe have become larger and more frequent. This trend has been driven by socioeconomic changes that have generated rural depopulation and changes in traditional land use. Within the Mediterranean Basin, the most contrasting socioeconomic conditions are found by comparing southern European with North African countries, and thus our hypothesis is that this difference generates contrasting fire regimes between the two regions. Specifically, we predict that current fire regimes in Mediterranean Africa resemble past fire regimes in the Mediterranean Europe when rural activities dominated the landscape. To test our hypothesis, we compared fire statistics from the western Rif (northern Morocco, 1988-2015) and from Valencia (eastern Spain, 1880-2014). The results suggest that the Rif has a typical Mediterranean fire regime with fires occurring in the hot, dry summer season. However, fires are very small and the annual pro-The final version will be published in Ecosystems (2018),
Revista Espanola De Herpetologia, 2003
La culebra lisa meridional muestra una distribucion global con poblaciones separadas desde el lim... more La culebra lisa meridional muestra una distribucion global con poblaciones separadas desde el limite Mioceno-Plioceno (europea versus africana), y posibles poblaciones aisladas en peninsulas normediterraneas (iberica, italiana), durante las glaciaciones cuaternarias. Para evaluar la posible variabilidad intraespecifica derivada de estos aislamientos, se estudiaron dos caracteres de su biometria y 10 de la folidosis en siete poblaciones que comprenden una parte significativa de su area de distribucion (Italia, Francia continental, Iberia al norte del Rio Ebro, Iberia Central, Iberia al sur del Rio Guadalquivir, montanas del Rif, y montanas del Atlas). Tanto las variables discretas como las continuas fueron consideradas conjuntamente mediante un analisis multivariante para variables mixtas. En conjunto, el dimorfismo sexual fue muy manifiesto en todas las poblaciones, tanto en caracteres previamente estudiados (ventrales, subcaudales), como en otros (hileras de dorsales). Se encontro relacion entre la talla corporal y el numero de escamas ventrales, planteando aqui la hipotesis de una mayor supervivencia en los ejemplares con mas ventrales. En el analisis regional, las poblaciones norteafricanas exhibieron tallas menores, aunque las correlaciones con la latitud no resultaron significativas. En folidosis, tambien aparecio tendencia geografica en el numero de ventrales, aunque la correlacion con la latitud solamente fue significativa en machos. No se detectaron cambios geograficos en la folidosis cefalica. La ausencia de variaciones geograficas significativas, no clinales, en los caracteres morfologicos aqui analizados,confirma la condicion monotipica de la especie.
PLOS ONE, 2016
Few DNA barcoding studies of squamate reptiles have been conducted. Due to the significance of th... more Few DNA barcoding studies of squamate reptiles have been conducted. Due to the significance of the Socotra Archipelago (a UNESCO Natural World Heritage site and a biodiversity hotspot) and the conservation interest of its reptile fauna (94% endemics), we performed the most comprehensive DNA barcoding study on an island group to date to test its applicability to specimen identification and species discovery. Reptiles constitute Socotra's most important vertebrate fauna, yet their taxonomy remains under-studied. We successfully DNA-barcoded 380 individuals of all 31 presently recognized species. The specimen identification success rate is moderate to high, and almost all species presented local barcoding gaps. The unexpected high levels of intra-specific variability found within some species suggest cryptic diversity. Species richness may be underestimated by 13.8-54.4%. This has implications in the species' ranges and conservation status that should be considered for conservation planning. Other phylogenetic studies using mitochondrial and nuclear markers are congruent with our results. We conclude that, despite its reduced length (663 base pairs), cytochrome c oxidase 1, COI, is very useful for specimen identification and for detecting intra-specific diversity, and has a good phylogenetic signal. We recommend DNA barcoding to be applied to other biodiversity hotspots for quickly and cost-efficiently flagging species discovery, preferentially incorporated into an integrative taxonomic framework.
File S1 Supporting information file including Text S1, Tables S1–S4, and Figure S1. Text S1. Desc... more File S1 Supporting information file including Text S1, Tables S1–S4, and Figure S1. Text S1. Description of the sampling methods. Table S1. Basic data of the 15 sampled plots and abundances of animal species: burnt logging (L1 to L5), burnt subsoiling (S1 to S5) and unburnt (U1 to U5); Data: species included (Y) and excluded (N) in statistical analyses according to the number of records. FG (feeding groups): zoophagous (1), phytophagous (2), saprovorous (3) and omnivorous (4). Table S2. List of plant species and presence in the three areas: logging (‘‘L’’), subsoiling (‘‘S’’) and unburnt (‘‘U’’). Table S3. R values and significance (* denotes p,0.05) from the ANOSIM taxonomic analysis of each animal group. The last rows are R values for the overall animal (abundance) and plant (presence/absence) species. The Global R column indicates the overall comparison of the three areas. The rest of the columns indicate the pairwise comparison between areas, with the R value and significance. A...
Restoration Ecology, 2012
In Mediterranean areas, river systems are key for maintaining regional biodiversity by providing ... more In Mediterranean areas, river systems are key for maintaining regional biodiversity by providing a high diversity of habitats. We studied bird community recovery for 9 years (2001-2009) during landscape restoration and Guadiamar Green Corridor establishment in the area affected by the Aznalcó llar mine spill (SW Spain, 1998). One year following plant restoration (3 years after the spill), values for α-and β-bird species diversity were high, sooner than reported for similar restoration processes elsewhere. Species richness, ecological diversity, and abundance increased only slightly in the following 8 years. Overlap between communities in sequential years, measured by similarity indexes, increased throughout the study period to about 70% during final survey years, and most breeding bird species present before the accident again inhabit the area. Only 5 years after the mine accident, bird communities in the restored site were similar in species richness, abundance, and diversity to an unaffected reference site; redundancy analysis demonstrated that bird communities were also similar between the reference river and the Guadiamar. Despite the severity of the mine accident, our results suggest a swift recovery of the bird community. We attribute this success to the rapid restoration of habitat availability and the resilience of the birds. This long-term study contributes to our limited knowledge of bird species response to habitat restoration following toxic spills in Mediterranean habitats.
Basic and Applied Herpetology, 2014
The energy gained by an organism is used for maintenance, growth and reproduction. In habitats wi... more The energy gained by an organism is used for maintenance, growth and reproduction. In habitats with limited resources, these processes compete for available energy and may induce intraspecific variation in body condition, growth trajectories and reproductive output. We tested the hypothesis that populations exposed to higher food availability are able to grow faster, and attain larger body sizes in the viperine snake (Natrix maura). We estimated snake age by counting growth lines in the skull's ectopterygoid bone, and compared body size growth curves from three Iberian populations exposed to temporal variation of food resources availability. In the three localities, and in males and females, the growth curves followed a quadratic function that tended to an asymptotic value as growth slowed down. Growth curves showed slower growth rates and an early asymptote for males, in agreement with the reverse sexual dimorphism in body size of this species. We also detected interpopulational differences, with the Ebro Delta population exhibiting slower growth rates and smaller asymptotic body size in both sexes. This population inhabits rice fields with an artificial waterflow cycle, a condition that implies a shorter period of prey availability for snakes, compared to the other two populations, where prey is available for longer periods of time. Moreover, high proportion of snakes with tail breakage in this population indicated high predation pressure. These environmental conditions suggest that food availability and predation pressure may be concurrently acting to produce smaller N. maura at the Ebro Delta than at the other two populations.
PLoS ONE, 2014
Fire is a major agent involved in landscape transformation and an indirect cause of changes in sp... more Fire is a major agent involved in landscape transformation and an indirect cause of changes in species composition. Responses to fire may vary greatly depending on life histories and functional traits of species. We have examined the taxonomic and functional responses to fire of eight taxonomic animal groups displaying a gradient of dietary and mobility patterns: Gastropoda, Heteroptera, Formicidae, Coleoptera, Araneae, Orthoptera, Reptilia and Aves. The fieldwork was conducted in a Mediterranean protected area on 3 sites (one unburnt and two burnt with different postfire management practices) with five replicates per site. We collected information from 4606 specimens from 274 animal species. Similarity in species composition and abundance between areas was measured by the Bray-Curtis index and ANOSIM, and comparisons between animal and plant responses by Mantel tests. We analyze whether groups with the highest percentage of omnivorous species, these species being more generalist in their dietary habits, show weak responses to fire (i.e. more similarity between burnt and unburnt areas), and independent responses to changes in vegetation. We also explore how mobility, i.e. dispersal ability, influences responses to fire. Our results demonstrate that differences in species composition and abundance between burnt and unburnt areas differed among groups. We found a tendency towards presenting lower differences between areas for groups with higher percentages of omnivorous species. Moreover, taxa with a higher percentage of omnivorous species had significantly more independent responses of changes in vegetation. High-(e.g. Aves) and low-mobility (e.g. Gastropoda) groups had the strongest responses to fire (higher R scores of the ANOSIM); however, we failed to find a significant general pattern with all the groups according to their mobility. Our results partially support the idea that functional traits underlie the response of organisms to environmental changes caused by fire.
Environmental Management, 2011
Fire is one of the commonest disturbances worldwide, transforming habitat structure and affecting... more Fire is one of the commonest disturbances worldwide, transforming habitat structure and affecting ecosystem functioning. Understanding how species respond to such environmental disturbances is a major conservation goal that should be monitored using functionally and taxonomically diverse groups such as Hymenoptera. In this respect, we have analyzed the taxonomic and functional response to fire and post-fire management of a Hymenoptera community from a Mediterranean protected area. Thus, Hymenoptera were sampled at fifteen sites located in three burnt areas submitted to different post-fire practices, as well as at five sites located in peripheral unburnt pine forest. A total of 4882 specimens belonging to 33 families, which were classified into six feeding groups according to their dietary preferences, were collected. ANOVA and Redundancy Analyses showed a taxonomic and functional response to fire as all burnt areas had more Hymenoptera families, different community composition and higher numbers of parasitoids than the unburnt area. Taxonomic differences were also found between burnt areas in terms of the response of Hymenoptera to post-fire management. In general the number of parasitoids was positively correlated to the number of potential host arthropods. Parasitoids are recognized to be sensitive to habitat changes, thus highlighting their value for monitoring the functional responses of organisms to habitat disturbance. The taxonomic and functional responses of Hymenoptera suggest that some pine-forest fires can enhance habitat heterogeneity and arthropod diversity, hence increasing interspecific interactions such as those established by parasitoids and their hosts.
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Books by Xavier Santos Santiró
Papers by Xavier Santos Santiró