Search

Species distribution models (SDMs) treat species as a single unit, neglecting intraspecific variation. Few studies address the impact of intraspecific variation on SDM performance, and none of them account for the well-known inter-algorithm variability in prediction performance. The endemic Iberian amphibian Lissotriton boscai comprises two geographically highly structured phylogenetic lineages, which allowed us to explore how intraspecific variation affects the overall performance of SDMs and the predicted ecological niche. We built species and lineage distribution models using three different presence‐only algorithms. We also tested for niche overlap, niche equivalency and niche similarity, using an ordination technique. We found differences in the predicted potential distribution of the two lineages and the underlying environmental factors. Moreover, intraspecific differences in model predictive capacity existed irrespective of which algorithm was used to build the distribution models. This was coupled with lineages showing a low degree of niche overlap and occurring in relatively different environmental niches spaces. The intraspecific variation observed in L. boscai led to an improved intraspecific predictivity of the lineage level based-distribution models. There was partial spatial agreement between the niche overlap and independently reported secondary contact zones. Thus SDMs built only at the species level may be too naive to predict impacts of global change on species distributions.

Services provided by protected areas (PAs) are based on their natural heritage, as stated in the conservation objectives, and many depend on their landscape, the spatial pattern of land cover patches. We study changes in the service provision of a PA based on its landscape changes. As services are defined according to the conservation objectives of the PA, this can be used in monitoring the PA conservation status. Using easily accessible historical land cover maps, landscape changes over time are identified and assessed according to changes in services provision, based on the PA conservation objectives. The PA under study is one of the oldest in Europe. Almost 80 years after its initial declaration, it was increased by incorporating surrounding areas. This helps to understand to what extent the oldest PA has conserved its environmental heritage, compared with what happened in the area most recently protected and not subjected to previous conservation regime. As expected in an area managed for conservation, changes in services in the older PA are small. But changes in the recently included area are also small and very similar to those ones. As change in ecosystem services are based on landscape changes, they do not relate only to the increase or decrease in the spatial distribution of single land covers but also on their joint spatial arrangement. This allows us to assess trade-offs among services provided by different land covers implied in landscape changes.

Understanding geographic variation in the characteristics of individuals and populations of species and/or closely related species is a long-standing research theme in biogeography and evolutionary biology. This endevour involves answering why species appear where they are; which are the factors driving species distributions; which is the relationship between the species and their environment; why closely related species or species populations share similar traits or environmental requirements; how species and species populations vary in space and time and which are the factors behind this heterogeneous response. Research on biogeographical variation involves recognizing and describing patterns and unveiling the processes behind them. This entails some challenges, mainly because these patterns may arise from a plethora of factors and mechanisms that may act together, simultaneously or separately, at different spatial and temporal scales. The best approach to address this is combining different sources of information at different spatio-temporal ecological and evolutionary scales with multiple hypotheses..., La comprensión de la variación geográfica de las características de los individuos y las poblaciones de las especies o de especies estrechamente emparentadas constituye un tema de estudio inveterado en biogeografía y biología evolutiva. Esta tarea supone responder a por qué las especies aparecen donde están; cuáles son los factores responsables de la distribución de las especies; cuál es la relación entre las especies y su entorno; por qué las especies o poblaciones de especies estrechamente emparentadas comparten rasgos o requisitos ambientales similares; cómo las especies y las poblaciones de las especies varían en el espacio y el tiempo y cuáles son los factores que explican esta respuesta heterogénea. La investigación sobre la variación biogeográfica implica el reconocimiento y la descripción de patrones y, a continuación, la dilucidación de los procesos subyacentes. Esto conlleva algunos retos, sobre todo porque dichos patrones pueden emerger como resultado de una plétora de factores y mecanismos que pueden actuar juntos, simultáneao independientemente, a diferentes escalas espaciales y temporales. El mejor enfoque para abordar esta cuestión consiste en combinar diferentes fuentes de información a diferentes escalas espacio-temporales, ecológicas y evolutivas con múltiples hipótesis...

[Aim]: Major efforts have been devoted to understanding the geographic pattern of sexual size dimorphism (SSD). Rensch's rule posits that SSD increases with body size in male-biased SSD species and decreases with body size in female-biased SSD species. This pattern, and its inverse, have been mainly explored at the interspecific level, whereas research at the intraspecific level has been largely neglected. Here, we test whether the allometric pattern of SSD in an urodele amphibian conforms to Rensch's rule and evaluate the relative role of four potential mechanisms: sexual selection, fecundity selection, density-dependent resource availability and differential plasticity., [Location]: Iberian Peninsula., [Taxon]: Lissotriton boscai (Amphibia: Caudata: Salamandridae)., [Methods]: We used original (field-based) and published data on body size, courtship behaviour and fecundity parameters and a suite of climatic, ecological and genetic (mitochondrial and nuclear markers) predictors to assess these hypotheses., [Results]: The results showed that SSD increased with increasing female mean body size, supporting the inverse Rensch's rule pattern. Primary productivity-related variables and female density were among the most relevant ecological predictors of SSD after accounting for genetic structure and capture date., [Main conclusions]: This study reveals that the interplay between the density-dependent resource availability hypothesis and the differential plasticity hypothesis explains the inverse Rensch's rule. We discuss how combining biogeographical and experimental approaches can provide alternative interpretations to the classical sexual and fecundity selection hypotheses on the interpopulation variation in SSD.

Ecological and evolutionary processes in natural populations are largely influenced by the population’s stage-structure. Commonly, different classes have different competitive abilities, e.g., due to differences in body size, suggesting that inter-class competition may be important and largely asymmetric. However, experimental evidence states that inter-class competition, which is important, is rare and restricted to marine fish. Here, we manipulated the adult density in six semi-natural populations of the European common lizard, Zootoca vivipara, while holding juvenile density constant. Adult density affected juveniles, but not adults, in line with inter-class competition. High adult density led to lower juvenile survival and growth before hibernation. In contrast, juvenile survival after hibernation was higher in populations with high adult density, pointing to relaxed inter-class competition. As a result, annual survival was not affected by adult density, showing that differences in pre- and post-hibernation survival balanced each other out. The intensity of inter-class competition affected reproduction, performance, and body size in juveniles. Path analyses unravelled direct treatment effects on early growth (pre-hibernation) and no direct treatment effects on the parameters measured after hibernation. This points to allometry of treatment-induced differences in early growth, and it suggests that inter-class competition mainly affects the early growth of the competitively inferior class and thereby their future performance and reproduction. These results are in contrast with previous findings and, together with results in marine fish, suggest that the strength and direction of density dependence may depend on the degree of inter-class competition, and thus on the availability of resources used by the competing classes.

Modeling species' habitat requirements are crucial to assess impacts of global change, for conservation efforts and to test mechanisms driving species presence. While the influence of abiotic factors has been widely examined, the importance of biotic factors and biotic interactions, and the potential implications of local processes are not well understood. Testing their importance requires additional knowledge and analyses at local habitat scale. Here, we recorded the locations of species presence at the microhabitat scale and measured abiotic and biotic parameters in three different common lizard (Zootoca vivipara) populations using a standardized sampling protocol. Thereafter, space use models and cross-evaluations among populations were run to infer local processes and estimate the importance of biotic parameters, biotic interactions, sex, and age. Biotic parameters explained more variation than abiotic parameters, and intraspecific interactions significantly predicted the spatial distribution. Significant differences among populations in the relationship between abiotic parameters and lizard distribution, and the greater model transferability within populations than between populations are in line with effects predicted by local adaptation and/or phenotypic plasticity. These results underline the importance of including biotic parameters and biotic interactions in space use models at the population level. There were significant differences in space use between sexes, and between adults and yearlings, the latter showing no association with the measured parameters. Consequently, predictive habitat models at the population level taking into account different sexes and age classes are required to understand a specie's ecological requirements and to allow for precise conservation strategies. Our study therefore stresses that future predictive habitat models at the population level and their transferability should take these parameters into account.

Rock-paper-scissors (RPS) dynamics, which maintain genetic polymorphisms over time through negative frequency-dependent (FD) selection, can evolve in short-lived species with no generational overlap, where they produce rapid morph frequency cycles. However, most species have overlapping generations and thus, rapid RPS dynamics are thought to require stronger FD selection, the existence of which yet needs to be proved. Here, we experimentally demonstrate that two cumulative selective episodes, FD sexual selection reinforced by FD selection on offspring survival, generate sufficiently strong selection to generate rapid morph frequency cycles in the European common lizard Zootoca vivipara, a multi-annual species with major generational overlap. These findings show that the conditions required for the evolution of RPS games are fulfilled by almost all species exhibiting genetic polymorphisms and suggest that RPS games may be responsible for the maintenance of genetic diversity in a wide range of species. © 2014 The Authors Published by the Royal Society. All rights reserved.

Investigating the factors affecting the strength of sexual selection is important for understanding the evolution of sex-specific morphological and behavioural traits. Traditionally, sexual selection studies focus on male ornaments, although recent evidence indicates that sexual selection mechanisms also target organismal performance. In the present study, we investigated the role of sexually dimorphic morphological and performance traits of the common (viviparous) lizard (Zootoca vivipara, Jacquin 1787) with respect to determining mating behaviour. Using an experimental set-up controlling for size differences, we found that males with longer tails had a higher probability of mating a female. Unexpectedly, males with lower bite forces had an advantage over males with higher bite forces, whereas males with bigger heads copulated for a longer time with the female. This shows that predicting mating success is not straightforward and is sometimes counterintuitive because a longer tail appears to be beneficial, whereas biting harder is not, for male Z.vivipara in a male-female interaction context. © 2013 The Linnean Society of London.