Alfredo G. Nicieza

• PhD
• Senior Lecturer at University of Oviedo

Assessing how genetic diversity is spatially structured underlies many research questions in evolutionary ecology and contributes to understanding the factors implicated in population declines and extirpations, facilitating identification of conservation priorities and decision-making. In this study, we surveyed genomic diversity using genotyping b...

Speciation, i.e., the formation of new species, implies that diverging populations evolve genetic and phenotypic factors that promote reproductive isolation (RI), but the adaptive vs. neutral origin of these factors and their relative contributions across the speciation continuum remain elusive. Here we test which of genomic, bioacoustic, morpholog...

The rich genetic and phenotypic diversity of species complexes is best recognized through formal taxonomic naming, but one must first assess the evolutionary history of phylogeographic lineages to identify and delimit candidate taxa. Using genomic markers, mitochondrial DNA barcoding and morphometric analyses, we examined lineage diversity and dist...

Critical thermal limits (CTmax and CTmin) decrease with elevation, with greater change in CTmin, and the risk to suffer heat and cold stress increasing at the gradient ends. A central prediction is that populations will adapt to the prevailing climatic conditions. Yet, reliable support for such expectation is scant because of the complexity of inte...

Serially connected robots are promising candidates for performing tasks in confined spaces such as search and rescue in large-scale disasters. Such robots are typically limbless, and we hypothesize that the addition of limbs could improve mobility. However, a challenge in designing and controlling such devices lies in the coordination of high-dimen...

Body shape and metabolic rate can be important determinants of animal performance, yet often their effects on influential traits are evaluated in a non-integrated way. This creates an important gap because the integration between shape and metabolism may be crucial to evaluate metabolic scaling theories. Here, we measured standard metabolic rate in...

Due to the speed of climate changes, rapid buffering mechanisms such as phenotypic plasticity – which may depend on breeding phenology – could be key to avoid extinction. The links between phenology and plasticity, however, remain understudied. Here we explored the matching between phenology and the thermal sensitivity of standard (SMR) and routine...

The ability to bear live offspring, viviparity, has evolved multiple times across the tree of life and is a remarkable adaptation with profound life-history and ecological implications. Within amphibians the ancestral reproductive mode is oviparity followed by a larval life stage, but viviparity has evolved independently in all three amphibian orde...

Reproductive isolation is instrumental to the formation of new species (speciation), but it remains largely enigmatic how many incompatibilities are required to prevent hybridization and where they lie across the genome. By studying patterns of admixture in amphibian hybrid zones, we found that reproductive isolation is initiated by numerous small-...

Critical thermal limits (CTmax and CTmin) are predicted to decrease with elevation, with greater change in CTmin, and the risk to suffer heat and cold stress increasing at the gradient ends. A central prediction is that populations will adapt to the prevailing climatic conditions. Yet, reliable support for such expectation is scant because of the c...

Explicitly accounting for phenotypic differentiation together with environmental heterogeneity is crucial to understand the evolutionary dynamics in hybrid zones. Species showing intra-specific variation in phenotypic traits that meet across environmentally heterogeneous regions constitute excellent natural settings to study the role of phenotypic...

Effective management of exploited populations is based on an understanding of population dynamics and evolutionary processes. In spatially structured populations, dispersal is a central process that ultimately can affect population growth and viability. It can be influenced by environmental conditions, individual phenotypes, and stochastic factors....

Many animals generate propulsive forces by coordinating legs, which contact and push against the surroundings, with bending of the body, which can only indirectly influence these forces. Such body–leg coordination is not commonly employed in quadrupedal robotic systems. To elucidate the role of back bending during quadrupedal locomotion, we study a...

The reduction in fecundity associated with the evolution of viviparity may have far‑reaching implications for the ecology, demography, and evolution of populations. the evolution of a polygamous behaviour (e.g. polyandry) may counteract some of the effects underlying a lower fecundity, such as the reduction in genetic diversity. comparing patterns...

Variation and population structure play key roles in the speciation process, but adaptive intraspecific genetic variation is commonly ignored when forecasting species niches. Amphibians serve as excellent models for testing how climate and local adaptations shape species distributions due to physiological and dispersal constraints and long generati...

The vulnerability of species to climate change is jointly influenced by geographic phenotypic variation, acclimation and behavioural thermoregulation. The importance of interactions between these factors, however, remains poorly understood. We demonstrate how advances in mechanistic niche modelling can be used to integrate and assess the influence...

Identifying the evolutionary processes that underlie morphological variation at the intraspecific level is cornerstone for understanding the drivers of phenotypic diversity at higher macro-evolutionary scales. The fire salamander, Salamandra salamandra, exhibits exceptional intraspecific variation in multiple phenotypic traits (i.e. body size, head...

Subdivided Pleistocene glacial refugia, best known as “refugia within refugia”, provided opportunities for diverging populations to evolve into incipient species and/or to hybridize and merge following range shifts tracking the climatic fluctuations, potentially promoting extensive cytonuclear discordances and “ghost” mtDNA lineages. Here we tested...

Insights into the causal mechanisms that limit species distributions are likely to improve our ability to anticipate species range shifts in response to climate change. For species with complex life‐histories, a mechanistic understanding of how climate affects different lifecycle stages may be crucial for making accurate forecasts. Here we use mech...

Complex life-histories may promote the evolution of different strategies to allow optimal matching to the environmental conditions that organisms can encounter in contrasting environments. For ectothermic animals, we need to disentangle the role of stage-specific thermal tolerances and developmental acclimation to predict the effects of climate cha...

The evolution of complex traits is often shaped by adaptive divergence. However, very little is known about the number, effect size, and location of the genomic regions influencing the variation of these traits in natural populations. Based on a dense linkage map of the common frog, Rana temporaria, we have localized, for the first time in amphibia...

The canonical model of sex-chromosome evolution predicts that, as recombination is suppressed along sex chromosomes, gametologs will progressively differentiate, eventually becoming heteromorphic. However, there are numerous examples of homomorphic sex chromosomes across the tree of life. This homomorphy has been suggested to result from frequent s...

Adaptation to warming climates could counteract the effects of global warming. Thus, understanding how species cope with contrasting climates may inform us about their potential for thermal adaptation and which processes may hamper that ability (e.g. evolutionary trade‐offs, phenology, or behavioural thermoregulation). In addition to temperature, t...

Many quadrupedal animals have lateral degrees of freedom in their backs that assist locomotion. This paper seeks to use a robotic model to demonstrate that back bending assists not only forward motion, but also lateral and turning motions. This paper uses geometric mechanics to prescribe gaits that coordinate both leg movements and back bending mot...

Dispersal is a central process in ecological and evolutionary dynamics because of its implications in spatially structured populations, that can affect population persistence either in the short or the long term. Movements away from the natal sites can be influenced by environmental conditions, individual phenotypes, and stochastic factors, but we...

This study probes the underlying locomotion principles of earliest organisms that could both swim and walk. We hypothesize that properly coordinated leg and body movements could have provided a substantial benefit toward locomotion on complex media, such as early crawling on sand. In this extended abstract, we summarize some of our recent advances...

Phenotypic plasticity can be viewed as the first level of defense of organism homeostasis against environmental stress and therefore represents the potential to deal with rapid environmental changes. Transitions between low complexity, artificial environments and complex, natural habitats can promote phenotypic plasticity. Here, we conducted an exp...

Individual animals introduced to supply existing populations may show a variety of physiological and phenotypic traits that may affect their performance in the wild, but a lack of monitoring after release usually precludes us from knowing the fate of different types of individuals and their impact on the recipient populations. Mark-recapture monito...

By combining 7077 SNPs and 61 microsatellites, we present the first linkage map for some of the early diverged lineages of the common frog, Rana temporaria, and the densest linkage map to date for this species. We found high homology with the published linkage maps of the Eastern and Western lineages but with differences in the order of some marker...

The existence of two or more distinctly coloured phenotypes among individuals of an interbreeding population is known as colour polymorphism. In amphibians, this phenomenon is pervasive among anurans, but rare or absent among salamanders and caecilians, respectively. Here, we examine whether various distinct phenotypes of Salamandra salamandra in N...

Aim The climate variability hypothesis ( CVH ) states that a positive relationship may exist between the breadth of thermal tolerance range and the level of climatic variability experienced by taxa with increasing latitude, especially in terrestrial ectotherms. Under CVH , we expected to find a correspondence between both thermal tolerance limits (...

In organisms such as fish, where body size is considered an important state variable for the study of their population dynamics, size-specific growth and survival rates can be influenced by local variation in both biotic and abiotic factors, but few studies have evaluated the complex relationships between environmental variability and size-dependen...

Measuring morphological disparity, an approximation to diversity, within-group variance of forms is an essential stage in order to evaluate effects of selection pressures which are acting on populations, promoting morphological differences (phenotypic plasticity), specialization or microevolutive processes.

Existen dos escenarios futuros de efectos del cambio climático sobre la biodiversidad de vertebrados: 1) Los ecosistemas se desplazan en conjunto en función del clima, y 2) Los ecosistemas se adaptan y cambian. El primero es poco realista debido a la tremenda y creciente fragmentación de hábitat en Europa y a la complejidad de las respuestas de las...

In species with simultaneous polyandry, male-biased operational sex ratio is expected to increase the risk of sperm competition and thus sperm traits affecting siring success can differ among populations. Here, we test the hypothesis that high male–female ratios will enhance sperm competitiveness of Rana temporaria males. In this species, local pop...

Seasonal time constraints can pose strong selection on life histories. Time-constrained animals should prioritise fast development over predation risk to avoid unfavourable growing conditions. However, changes in phenology could alter the balance between anti-predator and developmental needs. We studied variation of anti-predator strategies in comm...

1. As size is tightly associated with fitness, compensatory strategies for growth loss can be vital for restoring individual fitness. However, immediate and delayed costs of compensatory responses may prevent their generalization, and the optimal strategy may depend on environmental conditions. Compensatory responses may be particularly important i...

An approximation to the correlation analysis between shape and metabolic rate.

Morphological differentiation can be the result from either genetic and environmental factors, or from the interaction between both and a array of different phenotypes may be produced from a single genotype: phenotypic plasticity. Morphological disparity is caused by both genetic and environmental differences among individuals and phenotypic plasti...

Biodiversity is a reflection of genetic diversity, which is ultimately affected by a greater number of factors associated with human activity than any other level of biodiversity. The conservation of this biodiversity is therefore a main objective in the management of the natural environment. Global change is one of the major threats for biodiversi...

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Juvenile Atlantic salmon, Salmo salar, from two contrasting populations that had been reared under identical conditions differed in freshwater growth rates and the development of bimodality in length–frequency distributions. Segregation by size started at least a month earlier in the northern (River Shin, northern Scotland) than in the southern pop...

In organisms with complex life cycles, environmentally induced plasticity across sequential stages can have important consequences on morphology and life history traits such as developmental and growth rates. However, previous research in amphibians and other ectothermic vertebrates suggests that some morphological traits are generally insensitive...

The timing of many life history events shows phenotypic plasticity in response to the risk of predation. Theory predicts that increased risk of mortality in an early stage should select for switching earlier, while a higher risk after the transition should select for switching later. Here we examined the effects of stage-specific predation risk on...

Species Inhabiting habitats with different predators are expected to show divergent phenotypes for antipreciator traits. Here, we used a predator-prey system of dragonfly larvae and tadpoles to determine If vulnerability to a common predator differs in species with contrasting antipredator strategies. We examined the vulnerability of tadpoles of Ra...

Compensatory growth (CG) is a key issue in work aiming at a full understanding of the adaptive sig-nificance of growth plasticity and its carryover effects on life-history. The number of studies addressing evolutionary explanations for CG has increased rapidly during the last few years, but there has not been a parallel gain in our understanding of...

Compensatory growth (CG) is a key issue in work aiming at a full understanding of the adaptive sig-nificance of growth plasticity and its carryover effects on life-history. The number of studies addressing evolutionary explanations for CG has increased rapidly during the last few years, but there has not been a parallel gain in our understanding of...

Abstract Variations in the age structure and number of Atlantic salmon, Salmo salar L., running into the River Eo in northern Spain were assessed from catch records of sport fisheries for the period 1949 to 1991. The analysis focused on two periods (1951–1960 and 1981–1991) for which more complete data on fish number, size and age were available. O...

http://reddeparquesnacionales.mma.es/parques/rcg/documentos/resumen_10.pdf

1. To gain insight into the evolution of compensatory growth, we studied the growth patterns of anuran (Rana temporaria) larvae following either a period of exogenous growth depression (food restriction) or a period of endogenous depression (exposure to predators). We also investigated the potential deferred costs that larval compensatory growth co...

In species with complex life cycles hatching plasticity can provide an effective escape from egg predators, but theoretical studies predict a predation-risk trade-off across egg and larval stages. In this study, we examine whether the pres-ence of an egg predator can alter the timing of hatching in an anuran, Rana temp-oraria, and the consequences...

We investigated the role of constitutive morphology and previous experience in predator avoidance in two anuran species associated with different larval habitats. In Rana temporaria, deeper tails and larger body size conferred selective advantage against dragonfly predation. Previous experience with predators had a positive influence on the surviva...

Dispersal is essential for genetic flow and diversity, and can explain the spatial organization of a population. Dispersal processes are influenced by a plethora of factors acting at different spatial and temporal scales. Our main goal with this project is to explore some of those factors. We first analyse how the landscape structure affects disper...

Dispersal is essential for genetic flow and diversity, and can explain the spatial organization of a population. Dispersal processes are influenced by a plethora of factors acting at different spatial and temporal scales. Our main goal with this project is to explore some of those factors. We first analyse how the landscape structure affects disper...

Figure A1. Experimental arena used to evaluate the predator avoidance behavior of Discoglossus galganoi tadpoles in relation to food quality. The experimental trays contained "poor and safe" (P+S), and "rich and risky" (R+R) zones. In the R+R zone, larvae had full access to the food contained inside a Petri dish adjacent to a tube of plastic mesh c...

Metamorphosis can disrupt the correlation structure between juvenile and adult traits, thus allowing relatively independent evolution in contrasting environments. We used a multiple experimental approach to investigate how diet quality and larval predation risk affected the rates of growth and development in painted frogs (Discoglossus galganoi), a...

Summary 1. Adaptation to cold environments of ectotherm populations is expected to result in increased standard metabolic rates if resources are not limiting. However, it is still unclear how the maintenance of high standard metabolic rates would affect locomotor performance and its impact at the population level. 2. We compared standard metabolic...

We examined the influence of habitat size, growth opportunity, and the thermal conditions experienced during early development on the standard metabolic rate (SMR) of juvenile brown trout (Salmo trutta) from six natural populations to contrast the hypothesis of countergradient selection in metabolic rate. The study populations differed significantl...

This study assesses the influence of thermal regime on the development, survival rates and early growth of embryos of sea lamprey Petromyzon marinus incubated at five constant temperatures (7, 11, 15, 19 and 23° C). The time from fertilization to 50% hatching and from hatching to 50% burrowing were inversely related to incubation temperature. All t...

Both in foraging groups and in a sequential prey encounter context, learning had a visible effect on the pattern of selection for three live prey types (Ecdyonurus larvae, Hydropsyche larvae, and Gammarus) by juvenile Atlantic salmon Salmo salar. Compared to wild-caught fish, naive, hatchery-reared fish that had not been exposed to natural prey ate...

Compensatory growth is an organism's reaction to buffer deviations from targeted trajectories. We explored the compensatory patterns of juvenile brown trout under field and laboratory conditions. Divergence of size and condition trajectories was induced by manipulating food levels in the laboratory and then releasing the trout into a river. In the...

In salmonids, there seems to be a positive correlation between standard metabolic rate and growth rate under artificial rearing conditions. Several recent studies have suggested that phenotypic correlations between physiological or behavioural traits and developmental or life history responses might be common when assayed in low-complexity habitats...

Spain, possibly the EU’s richest country with regard to animal species, has the highest number of endemisms. The number of new species described every year indicates that a high percentage of the fauna remains unknown. Greater effort is required in our country with regard to taxonomic research. There exists much evidence of climatic effects on the...

Juvenile brown trout Salmo trutta from natural populations reacted to the presence of piscivorous brown trout by increasing the use of refuges. In contrast, second-generation hatchery fish and the offspring of wild fish raised under hatchery conditions were insensitive to predation risk. The diel pattern of activity also differed between wild and h...

Compensatory growth (CG) is a phase of accelerated growth when favourable conditions are restored after a period of growth depression. CG reduces variance in size by causing growth trajectories to converge and is important to fisheries management, aquaculture and life history analysis because it can offset the effects of growth arrests. Compensator...

Density can influence growth through exploitation competition and behavioural or chemical interference. Negative effects of population density on the growth rate of Sea Lamprey larvae have been reported in several field and laboratory studies, but the mechanisms involved are poorly understood. In this study the role of population density and waterb...

1. Anurans exhibit high levels of growth-mediated phenotypic plasticity in age and size at metamorphosis. Although temperature and food quality exert a strong influence on larval growth, little is known about the interacting effects of these factors on age and size at metamorphosis. 2. Plasticity in growth rates, maximum larval mass, mass loss, lar...

Anuran larvae exhibit high levels of phenotypic plasticity in growth and developmental rates in response to variation in temperature and food availability. We tested the hypothesis that alteration of developmental pathways during the aquatic larval stage should affect the postmetamorphic performance of the Iberian painted frog (Discoglossus galgano...

Age and size at metamorphosis are two important fitness components in species with complex life cycles. In anurans, metamorphic traits show remarkable phenotypic plasticity, especially in response to changes in growth conditions. It is also possible that the perception of risk directly determines changes in larval period and the size of metamorphs....

1. This study examines the aggregation behaviour and activity of larvae of the Common Frog Rana temporaria in relation to the early social environment, ontogeny and the presence of chemical cues from a predatory fish to address three main questions: (i) Does previous social interaction influence aggregation behaviour in later developmental stages?...

1. Agonistic behaviour can be an important trait in determining individual success under interference competition, but it also generates energetic and physiological costs. The ensuing trade-off is expected to be dependent on the individual state. This study tests whether aggression patterns of juvenile Atlantic Salmon Salmo salar are linked to the...

Both in foraging groups and in a sequential prey encounter context, learning had a visible effect on the pattern of selection for three live prey types (Ecdyonurus larvae, Hydropsyche larvae, and Gammarus) by juvenile Atlantic salmon Salmo salar. Compared to wild-caught fish, naive, hatchery-reared fish that had not been exposed to natural prey ate...

The effects of light level, developmental pathway, and previous growth history on the foraging attack distances of juvenile Atlantic salmon Salmo salar were examined in circular rearing tanks. Former manipulation of growth rates had no significant influence on distances moved to intercept food items despite the fact that it caused substantial diffe...

The effects of light level, developmental pathway, and previous growth history on the foraging attack distances of juvenile Atlantic salmon Salmo salar were examined in circular rearing tanks. Former manipulation of growth rates had no significant influence on distances moved to intercept food items despite the fact that it caused substantial diffe...

This study examines behavioral and physiological responses of juvenile At-lantic salmon (Salmo salar) adopting alternative life history patterns following a period of reduced growth. We manipulated the growth rates of premigratory and nonmigratory salmon by either reducing food availability or maintaining water at low temperature (4–6C). A third gr...

Relationships between the fish community and selected habitat features were examined in a set of short temperate streams located at the northern end of the Iberian Peninsula. The fish fauna in these streams consists mostly of diadromous or estuarine species. Species richness and diversity increased with stream order, depth and width and decreased w...

1. Previous studies suggest that morphological divergence among populations is a widespread result of reproductive isolation and local adaptation. In this paper I test the hypothesis that morphological differentiation should be reduced when individuals shift from a geographically heterogeneous habitat (benthic, fresh water) to a relatively uniform...

European Atlantic salmon (Salmo salar) populations inhabit rivers from northern Portugal to northern Norway across a wide spectrum of environmental variability. To address whether single physical factors might lead to genetic divergence of isolated populations, we compared the digestive performances total digestibility, relative nitrogen digestibil...

Scale analysis indicated that two-sea-winter (2SW) Atlantic salmon (Salmo salar) had a greater growth increment during the first year at sea than 1SW of the same smelt year in the Rivers Narcea and Esva, but no differences were found between sea age-classes in the River Cares. Interannual variation in marine growth was synchronized among rivers. Va...

Effects of angling exploitation on brown trout populations were assessed by comparing fished sections with close ones unfished for at least 20 years, in mountain streams of Asturias (Northern Spain). Both the fish size and age structure significantly differed among sections in the expected direction according to their exploitation status. The main...

Une méthode de détermination externe du sexe basée sur le dimorphisme sexuel de la longueur relative de la mâchoire supérieure est appliquée chez le Saumon Atlantique (Salmo salar L.). 78 adultes capturés en juin et juillet 1990 dans trois rivières des Asturies (Nord de l'Espagne) sont étudiés. L'Analyse Linéaire Discriminante sur un échantillon de...