Search

Turbidity represents an obstacle to visual acuity underwater that might entail considerable consequences for multiple faunal traits. Morphology, especially eye size, could be adjusted to cope with reduced visibility in turbid water. Moreover, turbidity could interfere with colour signals or crypsis. Turbid water may simul-taneously impair the ability of prey and predators to detect each other, which may cause reduced speed, flight initiation distance, activity time, boldness, and exploratory behaviour by prey, In this work, we compared these traits in larvae of the newt Pleurodeles waltlfrom transparent and turbid ponds (around 100 and 300 FTU, respectively). Body size did not differ between pond types, but larvae from turbid ponds had smaller eyes, probably because visual acuity is structurally hindered by the environment. Colouration did not differ between transparent and turbid ponds on average, but it was more variable in larvae from transparent than turbid ponds, probably because transparent ponds trigger crypsis towards diverse background colours, whereas turbid ponds promote reduced pigmentation in all cases., In addition, behavioural traits were gauged in larvae from both types of ponds, in tests conducted in either transparent or turbid water. Speed was unaffected by turbidity, but larvae from turbid ponds increased their flight initiation distance when tested in transparent water. In all cases, larvae from transparent ponds were more active, and bolder in transparent water, and all larvae were more ex-ploratory when tested in transparent water (regardless of which pond type they came from)., Turbidity could trigger more cautious behaviours, probably because it makes predators harder to track. Alternatively, transparent water could stimulate a more expansive use of space through improved visibility, or it might encourage a more active search for shelter., These results shed light on the role of turbidity as a promotor of morphological and behavioural variability in amphibian larvae. These ecological consequences of water turbidity can be framed in terms of energy allocation and detectability in the context of predator–prey interactions.

Understanding the mechanistic implications behind wildlife responses to global changes is a central topic in eco-evolutionary research. In particular, anthropic pollution is known to impact wild populations across the globe, which may have even stronger consequences for species with complex life cycles. Among vertebrates, amphibians represent a paradigmatic example of metamorphosis, and their characteristics make them highly vulnerable to pollution. Here, we tested for differences in the redox status, telomere length, and locomotor performance across life stages of green frogs (Pelophylax perezi) from agrosystem and natural habitats, both constitutively and in response to an experimental ammonium exposure (10 mg/L). We found that larvae from the agrosystem constitutively showed an enhanced redox status (better antioxidant balance against H2O2, lower lipid peroxidation) but shorter telomeres as compared to larvae from the natural environment. The larval redox response to ammonium was, overall, similar in both habitats. In contrast, after metamorphosis, the redox status of individuals from the natural habitat seemed to cope better with ammonium exposure (denoted by lower lipid peroxidation), and differences between habitats in telomere length were no longer present. Intriguingly, while the swimming performance of larvae did not correlate with individual's physiology, metamorphs with lower glutathione reductase activity and longer telomeres had a better jumping performance. This may suggest that locomotor performance is both traded off with the production of reactive oxygen species and potentiated directly by longer telomeres or indirectly by the mechanisms that buffer their shortening. Overall, our study suggests that contrasting land-use histories can drive divergence in physiological pathways linked to individual health and lifespan. Since this pattern was life-stage dependent, divergent habitat conditions can have contrasting implications across the ontogenetic dev

A primeros del presente siglo, el premio Nobel de Química neerlandés Paul J. Crutzen y el biólogo estadounidense Eugene F. Stoermer propusieron que nuestro planeta había cambiado de era geológica, abandonando el Holoceno y dando paso al Antropoceno, dentro del período Cuaternario (Crutzen y Stoermer, 2000). Esta propuesta rápidamente se granjeó el apoyo de la comunidad científica (Crutzen et al., 2007; Steffen et al., 2011), y se emplea hoy en centenares de libros y artículos especializados, se cita miles de veces y se usa cada vez más en los medios de comunicación (Ulloa, 2017). El concepto se acuñó para designar las interacciones mutuas entre las modificaciones en el clima, los cambios en la biodiversidad, la rápida acumulación de gases de efecto invernadero y los daños irreversibles ocasionados por el consumo excesivo de recursos naturales por parte del ser humano (Trischler, 2017). Por ende, el Antropoceno define la época en la que las actividades del ser humano empezaron a provocar cambios biológicos y geofísicos a escala mundial. Se ha comprobado que estos cambios han alterado el relativo equilibrio en que se mantenía el sistema terrestre desde los comienzos de la época holocena (desde 11.700 años atrás). Tristemente, esta nueva época con registro estratigráfico está asociada a la llamada sexta extinción masiva de las especies, cuya diferencia con las anteriores radica en que esta está causada por Homo sapiens. Esto es debido a que en los últimos cien años la población humana se ha incrementado seis veces, y su actividad económica diez veces en los últimos cincuenta años. La definición de Antropoceno lleva implícita que ha de tener un registro estratigráfico de la actividad humana para poder diferenciarlo del Holoceno (Waters et al., 2016). Técnicamente, solo con el poso de la bomba atómica la definición es suficiente para diferenciar el Antropoceno del Holoceno, pero hay muchas más evidencias (los llamados tecnofósiles, etc.). Sin embargo, parece ser un debat, Estos desencadenantes no funcionan de forma aislada, sino a través de complejas sinergias que actúan a múltiples niveles (Hardy, 2003; Osmond et al., 2004; Camarero et al., 2004). Por ejemplo, los cambios en el uso del suelo implican un aumento en área de tierras de cultivo (Veldkamp and Lambin, 2001; Ewers et al., 2009) y un predominio creciente de las técnicas agrícolas intensivas sobre las tradicionales (Nonhebel, 2002; Calderón et al., 2012), lo que conlleva un incremento en las emisiones de gases de efecto invernadero que contribuyen al calentamiento global (Caballero et al., 2007; González et al., 2007; Johnson et al., 2007). Las prácticas agrícolas también representan un aporte notable de nitrógeno a través de fertilizantes (Olivares et al., 2013; Cárdenas-Navarro et al., 2004), que en gran medida percola en el medio (Stark and Richards, 2008; Benintende et al., 2008). Además, estos hábitats enriquecidos con nutrientes facilitan el establecimiento de plantas, animales e incluso microorganismos exóticos (Pimentel et al., 2001; Guillemaud et al., 2011). Por su parte, las alteraciones en los rangos de distribución de las especies pueden modificar las relaciones ecológicas preexistentes (Schweiger et al., 2008; Lobo, 1999), o dar lugar a interacciones novedosas (Tylianakis et al., 2008), que pueden amenazar el equilibrio de los ecosistemas. De hecho, las invasiones biológicas se han considerado durante mucho tiempo entre las principales consecuencias del cambio global (Lövei, 1997; Alonso et al., 2015). De excepcional relevancia son los casos recientes de expansión geográfica de patógenos (Wilcox and Gubler, 2005) a medida que sus huéspedes (Seimon et al., 2007) o vectores (Léger et al., 2013) siguen climas más permisivos, se ven favorecidos por cambios en los usos del suelo, o se extienden gracias el uso o comercio de animales (Randolph, 2009; Jiménez-Clavero, 2012; Kutz et al., 2013). A esta complejidad inherente al cambio global antropogénico hay que añadir ef

Habitat degradation and climate change are major threats to the long-term persistence of reptile populations. However, their roles on primary productivity instability remain unclear at certain scales. Besides, the design of protected areas has often overlooked reptiles or assumed that their ecological requirements are represented under the umbrella of more charismatic species. Here, we assess the vulnerability of areas of high diversity of reptiles in the Iberian Peninsula to global change using data from satellite imagery. We focused on primary productivity, climate and land-use change because they are indicators of environmental variability that might impair ecosystem functioning and alter wildlife communities. We used linear regressions to detect monotonic temporal trends in primary productivity (through the enhanced vegetation index, EVI) and climate (mean temperature and accumulated precipitation) at two spatial resolutions (10-km2 UTM squares and CORINE land-cover polygon level) over the period 2000–2020. We also determined how the strength of land-use and climate change affected the intensity of change in primary productivity at both spatial scales with multivariate linear regressions. We identified 339 hotspots (10-km2 UTMsquares) andmonotonic increments of temperature, EVI or both occurred in 43%, 16%and 22%of them, respectively. Positive trends of the EVI were related to increasing temperatures and changes in shrubland and forest cover. Within the hotspots with monotonic increments in EVI and temperature, EVI increments occurred in 65 % of the CORINE polygons that did not change their land-cover type, with stronger increases in tree crops. Finally, the Natura 2000 network provides only moderate protection to reptile hotspots, being most of the vegetation types relatively underrepresented. The proportion of forest and shrubland protected by the Natura 2000 network was higher in hotspots where EVI changed. Our procedures are relevant to prioritize hotspots r

Colonization of new habitat patches is a key aspect of metacommunity dynamics, particularly for sessile organisms. Mosses can establish in new patches through fragmentation, with different vegetative structures acting as propagules. Despite the importance of these propagules for successful colonization the specific aspects that favour moss colonization by vegetative propagules remain poorly understood, including the effect of propagule size. We examine the intra- and interspecific variation of establishment and colonization success in culture of propagules of different sizes in six widespread soil moss species of contrasting growth form (Dicranum scoparium, Homalothecium aureum, Hypnum cupressiforme, Ptychostomum capillare, Syntrichia ruralis and Tortella squarrosa). We obtained three different size classes of propagules from artificially fragmented vegetative material, and assessed their establishment under controlled light and temperature conditions. We characterize the size, shape, apparent viability, morphological type and size changes due to hydration states of the propagules, all of them traits with potentially significant influence in their dispersal pattern and establishment. Then we assess the effect of these traits on moss establishment, using indicators of surface establishment (number of established shoots and colonized surface) and biomass production (viable biomass) as proxies of colonization success. The establishment indicators related to colonization surface and biomass production differ among species and propagule sizes. The magnitude of the interspecific differences of all indicators of establishment success was larger at the smaller propagule size class. T. squarrosa was the most successful species, and D. scoparium showed the lowest performance. We also found interspecific differences in the hydration dynamics of the propagules. The process of establishment by vegetative fragments operates differently among moss species. Besides, differences bet

Water contamination poses an important challenge to aquatic fauna, including well-documented effects on amphibian larvae. However, little is known about how contamination during the larval stages may affect post-metamorphic phases, or whether resistance may have evolved in some populations. In this work, we tested the hypothesis that chronic exposure to ammonium (a common contaminant in agroecosystems with confirmed effects on anuran tadpoles) during the larval stage of Pelophylax perezi frogs would affect growth and locomotor performance of metamorph, juvenile, subadult and adult stages. We also predicted that the effects of ammonium would be milder in offspring originated from parental agroecosystem frogs than those originating from forests. We compared tadpoles from both habitats either reared in untreated water or chronically exposed to ammonium. We found that exposure to ammonium during the larval stage inflicted effects on morphology (different measures of body size) and swimming speed after metamorphosis until adulthood. However, these effects were not always consistent through post-metamorphic stages and the effects differed as a function of treatment and habitat. In adults, body size and condition were greater in non-ammonium and ammonium exposed individuals, respectively. These differences were not detectable in metamorphs, for which only ammonium-exposed individuals from agroecosystem showed reduced body size in intermediate post-metamorphic stages. In turn, treatment reduced jumping distance only in agroecosystem adults, subadults and juveniles, which was opposite to the trend observed just after metamorphosis. These changes of patterns throughout the ontogeny of P. perezi could be due to processes such as compensatory growth, delayed energy costs derived from it, or early sexual differences that could be present even before they can be accounted for. In summary, this study suggests that exposure to ammonium during larval stages can result in diverse bio

Among others, the global change involves a worldwide increase in cropland area, with the concomitant rise in nitrogenous fertilizer supplementation and species range alterations, including parasites and pathogens. As most animals rely on their immune systems against these infectious agents, studying the potential effects of nitrogenous compounds on animal immune response is vital to understand their susceptibility to infections under these altered circumstances. Being subjected to an alarming process of global declines, amphibians are the object of particular attention, given their sensitivity to these compounds, especially to ammonium. Moreover, whereas adults can actively avoid polluted patches, larvae are confined within their waterbodies, thus exposed to contaminants in it. In this work, we test whether chronic exposure to a sublethal dose of ammonium during the larval stage of Pelophylax perezi frogs, released from all contamination after metamorphosis, leads to impaired inflammatory response to phytohemagglutinin in adults. We also test whether such a response differs between agrosystem individuals as compared with conspecifics from natural habitats. We found negative carryover effects of chronic exposure of larvae to ammonium on adult inflammatory response, which could imply a greater susceptibility to pathogens and parasites. However, this damage is only true for males, which, according to the immunocompetence handicap hypothesis, could be a consequence of a testosterone-triggered impairment of male immune function. In disagreement with our prediction, however, we detected no differences in the inflammatory response of agrosystem frogs to phytohemagglutinin as compared with natural habitat conspecifics.

Several constituents of the current global change are usually deemed accountable for the worldwide declines of amphibian populations. Among these, water contamination poses a major threat, especially to larval stages, which are unable to escape a polluted water body. This problem is remarkable in agrosystems, one of the main sources of water pollution and whose area is forecasted to increase in the forthcoming decades. However, pollutants represent a selective pressure that may result in tolerance in affected areas. In this work, we tested whether chronic exposure to a sublethal concentration of ammonium (10 mg/L), one of the most frequent agrochemicals, affects differently hatching success, survivorship, morphology and swimming performance of Pelophylax perezi tadpoles from agrosystem and pine grove habitats. Ammonium diminished survivorship at the earliest stages after hatching. Thus, lower density was a by-product of exposure to ammonium. Higher density slowed down development, reduced snout-vent length, and had a sharper negative effect on body mass and tail length and depth of ammonium treated individuals with respect to the control. In turn, ammonium accelerated development and increased body mass, SVL, and tail length and depth. These effects did not depend on provenance habitat. However, only pine grove tadpoles’ swimming speed was negatively affected by ammonium, which supports the hypothesis that agrosystem tadpoles are more tolerant to ammonium. Finally, corroborating previous findings, tadpoles with larger bodies and tails were faster swimmers, whereas proportionally more massive individuals were slower, and tail depth was unrelated to swimming speed.

[AIM]: Local suitability estimated with species distribution models (SDMs) could indicate the maximum abundance attainable by species. Often the abundance–suitability relationship is wedge-shaped because species do not reach their maximum potential in every suitable location. We explore how SDM performance, the amount of information lost when converting continuous abundance into presence–absence data and species prevalence influence the abundance–suitability relationship., [LOCATION] Undefined, [TIME PERIORD] Undefined, [MAJOR TAXA] Virtual species, [METHODS] Different abundance scenarios were simulated and converted into presence–absence maps. SDMs were parameterized using simulated predictors with different explanatory capacities. Quantile regressions were performed to characterize the abundance–suitability relationship. The strength of the wedge-shaped pattern was estimated using the difference in slopes between the 90th and 50th quantile lines, the goodness-of-fit of the 90th quantile regressions was calculated, and variation of both parameters was analysed as a function of SDM performance, prevalence and maximum abundance., [RESULTS] The degree of wedge shape was directly related to maximum abundance. It also depended on SDM quality; the higher the discrimination capacity, the less wedge-shaped the abundance–suitability relationship and higher the goodness-of-fit of the 90th quantile regressions. Prevalence exerted a significant effect on the shape of the relationship by influencing—together with maximum abundance—the extent of information loss., [MAIN CONCLUSIONS] SDMs cannot predict actual abundance even when the true determinants of abundance are included as predictors. Because presence–absence and abundance data are related but are different variables, wedge-shaped patterns are unavoidable. Discrimination capacity and prevalence affect the strength of the wedge-shaped pattern, so understanding their effects is necessary before any biological explanation is provided for the abundance–suitability relationship. Suitability maps derived from SDMs may transmit a false sense of precision at a local scale and should not be used as a perfect surrogate when abundance information is required.

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.

Aim: Local suitability estimated with species distribution models (SDMs) could indicate the maximum abundance attainable by species. Often the abundance–suitability relationship is wedge-shaped because species do not reach their maximum potential in every suitable location. We explore how SDM performance, the amount of information lost when converting continuous abundance into presence–absence data and species prevalence influence the abundance–suitability relationship. Location: Undefined. Time period: Undefined. Major taxa: Virtual species. Methods: Different abundance scenarios were simulated and converted into presence–absence maps. SDMs were parameterized using simulated predictors with different explanatory capacities. Quantile regressions were performed to characterize the abundance–suitability relationship. The strength of the wedge-shaped pattern was estimated using the difference in slopes between the 90th and 50th quantile lines, the goodness-of-fit of the 90th quantile regressions was calculated, and variation of both parameters was analysed as a function of SDM performance, prevalence and maximum abundance. Results: The degree of wedge shape was directly related to maximum abundance. It also depended on SDM quality; the higher the discrimination capacity, the less wedge-shaped the abundance–suitability relationship and higher the goodness-of-fit of the 90th quantile regressions. Prevalence exerted a significant effect on the shape of the relationship by influencing—together with maximum abundance—the extent of information loss. Main conclusions: SDMs cannot predict actual abundance even when the true determinants of abundance are included as predictors. Because presence–absence and abundance data are related but are different variables, wedge-shaped patterns are unavoidable. Discrimination capacity and prevalence affect the strength of the wedge-shaped pattern, so understanding their effects is necessary before any biological explanation is provided for, Ministerio de Economía y Competitividad (MINECO), Depto. de Biodiversidad, Ecología y Evolución, Fac. de Ciencias Biológicas, TRUE, pub

[Aim]: The conservation of biodiversity is hampered by data deficiencies, with many new species and subspecies awaiting description or reclassification. Population genomics and ecological niche modelling offer complementary new tools for uncovering functional units of phylogenetic diversity. We hypothesize that phylogenetically delineated lineages of gentoo penguins (Pygoscelis papua) distributed across Antarctica and sub-Antarctic Islands are subject to spatially explicit ecological conditions that have limited gene flow, facilitating genetic differentiation, and thereby speciation processes. [Location]: Antarctica and sub-Antarctic area. [Methods]: We identify divergent lineages for gentoo penguins using ddRAD-seq and mtDNA, and generated species distribution models (SDMs) based on terrestrial and marine parameters. Results: Analyses of our genomic data supports the existence of four major lineages of gentoo penguin: (i) spanning the sub-Antarctic archipelagos north of the Antarctic Polar Front (APF); (ii) Kerguelen Island; (iii) South America; and (iv) across maritime Antarctic and the Scotia Arc archipelagos. The APF, a major current system around Antarctica, acts as the most important barrier separating regional sister lineages. Our ecological analyses spanning both the terrestrial (breeding sites) and marine (feeding sites) realms recover limited niche overlap among the major lineages of gentoo penguin. We observe this pattern to correspond more closely with regional differentiation of marine conditions than to terrestrial macroenvironmental features. [Main conclusions]: Recognition of regional genetic lineages as discrete evolutionary entities that occupy distinct ecological niches and also differ morphologically should be considered a priority for conservation. Gentoo penguins provide a good example of how conservation policy can be directly impacted by new insights obtained through the integration of larger genomic datasets with novel approaches to ecologic

Foraging is key for most animals, because their energy and matter income depend on food ingestion. However, animals may respond adaptively to perceived competitor and/or predator proximity by modifying their foraging rates. Increased foraging activity is expected to improve the chances of succeeding in competition. However, the benefits of increased foraging activity could be offset by the risks of increased conspicuousness to predators. Plus, starvation may have counteracting or additive effects on foraging behaviour. Here, we test these hypotheses in larval Iberian ribbed newts (Pleurodeles waltl). We estimated foraging rates of individuals haphazardly assigned to either a restricted or an unrestricted-feeding regime, in water with (1) self-odour as control, (2) predator Dytiscus sp. chemical cues, and (3) competitor conspecific larva chemical cues. Treatments were presented in a random sequence. Newt larvae responded to either predator or conspecific chemical cues by increasing foraging rates relative to the control. Conspecific chemical cues increased foraging rates over the other two treatments. Feeding regime did not modify larva response to perceived predator and competitor proximity. Increased foraging rates in the presence of conspecific chemical cues could simultaneously improve larval energetic status to face competition and reduce prey available for the competitor. Intermediate foraging rates in the presence of predator chemical cues suggest a trade-off between the benefits (likely improved energetic status or accelerated metamorphosis) and the costs (likely increased conspicuousness) of increased food ingestion. These results prove that larval newts adjust foraging rates to perceived predator and competitor proximity.

[Aim]: Correlative species distribution models (SDMs) are subject to substantial spatio-temporal limitations when historical occurrence records of data-poor species provide incomplete and outdated information for niche modelling. Complementary mechanistic modelling techniques can, therefore, offer a valuable contribution to underpin more physiologically informed predictions of biological invasions, the risk of which is often exacerbated by climate change. In this study we integrate physiological and human pressure data to address the uncertainties and limitations of correlative SDMs and to better understand, predict and manage biological invasions., [Location]: Western archipelagos of the Southern Ocean and martime Antarctica., [Taxon]: Eretmoptera murphyi (Chironomidae), invertebrates., [Methods]: Mahalanobis Distances were used for correlative SDM construction for a species with few records. A mechanistic SDM was built around different fitness components (larval survival and life stage progression) as a function of temperature. SDM predictions were combined with human activity levels in Antarctica to generate a site vulnerability index to the assess colonization risk of E. murphyi. Future scenarios of ecophysiological suitability were built around the warming trends in the region., [Results]: Both SDMs converge to predict high environmental suitability in the species' native and introduced ranges. However, the mechanistic model indicates a slightly larger invasive potential based on larval performance at different temperatures. Human activity levels across the Antarctic Peninsula play a key role in discerning site vulnerabilities. Niche suitability in Antarctica grows considerably under long-term climate scenarios, leading to a substantially higher invasive threat to the Antarctic ecosystems. In turn changing conditions result in growing physiological mismatches with the environment in the native range in South Georgia., [Main conclusions]: Long-term studies of invasion potential under climate benefit from integrating correlative predictions with physiological experiments, as the invasion potential varies depending on the area and the timescale examined. This study also highlights a conservation paradox whereby the accidental introduction of an insect represents a threat to the Antarctic ecoystems that contrasts with its endangered status at the native range.

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...

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...

1. How predation events experienced by preys can shape phenotypic traits through the ontogenetic development of the interacting species should be a key issue in Evolutionary and Conservation Biology. 2. Locomotor performance plays a fundamental role on the fitness of many animals, mainly because it enhances ability to fleeing from predators. Predators represent indeed a capital selective force on prey, mainly because they end prey life. However, predators may also damage prey by other means, such as injuries caused by failed attacks. This damage can severely affect locomotion, among several other aspects of prey fitness. In the case of anuran tadpoles, failed predator attacks often result in injured tails, which reduces swimming performance. However, little is known about lasting effects of those failed attacks on fleeing capabilities after metamorphosis. 3. In this work, we clipped 55% tail length of pre-tail-resorption stage anaesthetized larval Pelobates cultripes toads, and compared metamorph hindlimb length and jump distance with metamorphs resulting from anaesthetized and non-anaesthetized non-clipped controls. Previous findings showed that this treatment produced metamorphs with reduced body condition. 4. Results herein suggest that partial tail loss in tadpoles diminishes jumping performance of resultant metamorphs. This effect is likely a consequence of tail-clipped tadpoles developing shorter hindlimbs as metamorphs, which is parallel to their reduced body condition. 5. Therefore, predator attacks in the tail may be less potentially mortal than those in the head and body, but have costs in terms of an efficient antipredatory response that persist in post-metamorphic stage. This effect might compromise metamorph ability to survive subsequent predator attacks.

The ecological niches of the three Iberian Argiope species have not been studied in quantitative detail, and recently developed approaches for assessing niche overlap have rarely been applied to invertebrates. This study aimed to quantify the climatic niche differences between Argiope bruennichi (Scopoli, 1772), A. lobata (Pallas, 1772) and A. trifasciata (Forsskål, 1775) in the Iberian Peninsula. An extensive occurrence database for the three species was compiled from the literature, a citizen science project (Biodiversidad Virtual) and a social network (Flickr). Niche comparison and recursive partitioning analyses were used to compare and characterize the niches of these species using regional climatic information. The three Argiope species had different distribution patterns within the Iberian Peninsula with a clear degree of sympatry. Despite an appreciable niche overlap, the three species had significantly different climatic niches. A. bruennichi was present in colder and more humid environments, while A. lobata and A. trifasciata selected warmer, drier environments. A. trifasciata preferred areas with higher minimum temperatures than A. lobata and avoided continental environments that the two other species tolerated. Despite these differences, the Iberian Peninsula contained a broad range of suitable environments where more than one species co-occurred. Further studies are needed to explore these species relationships, particularly given the trend of ranges shifting north due to global warming. Considering both the results of this study and the increasingly xeric conditions in the Iberian Peninsula, A. lobata and A. trifasciata may benefit at the expense of a retraction of A. bruennichi.

The distribution of terrestrial biodiversity within Antarctica is complex, with 16 distinct biogeographic regions (Antarctic Conservation Biogeographic Regions) currently recognised within the Antarctic continent, Peninsula and Scotia Arc archipelagos of the Antarctic Treaty area. Much of this diversity is endemic not only to Antarctica as a whole, but to specific regions within it. Further complexity is added by inclusion of the biodiversity found on the islands located in the Southern Ocean north of the Treaty area. Within Antarctica, scientific, logistic and tourism activities may inadvertently move organisms over potentially long distances, far beyond natural dispersal ranges. Such translocation can disrupt natural species distribution patterns and biogeography through: (1) movement of spatially restricted indigenous species to other areas of Antarctica; (2) movement of distinct populations of more generally distributed species from one area of Antarctica to another, leading to genetic homogenisation and loss of assumed local patterns of adaptation; and (3) further dispersal of introduced non-native species from one area of Antarctica to another. Species can be moved between regions in association with people and cargo, by ship, aircraft and overland travel. Movement of cargo and personnel by ship between stations located in different biogeographic regions is likely to present one of the greatest risks, particularly as coastal stations may experience similar climatic conditions, making establishment more likely. Recognising that reducing the risk of inter-regional transfer of species is a priority issue for the Antarctic Treaty Consultative Meeting, we make practical recommendations aimed at reducing this risk, including the implementation of appropriate biosecurity procedures.

How predation events experienced by preys can shape phenotypic traits through the ontogenetic development of the interacting species should be a key issue in Evolutionary and Conservation Biology. Locomotor performance plays a fundamental role on the fitness of many animals, mainly because it enhances ability to fleeing from predators. Predators represent indeed a capital selective force on prey, mainly because they end prey life. However, predators may also damage prey by other means, such as injuries caused by failed attacks. This damage can severely affect locomotion, among several other aspects of prey fitness. In the case of anuran tadpoles, failed predator attacks often result in injured tails, which reduces swimming performance. However, little is known about lasting effects of those failed attacks on fleeing capabilities after metamorphosis. In this work, we clipped 55% tail length of pre-tail-resorption stage anaesthetized larval Pelobates cultripes toads, and compared metamorph hindlimb length and jump distance with metamorphs resulting from anaesthetized and non-anaesthetized non-clipped controls. Previous findings showed that this treatment produced metamorphs with reduced body condition. Results herein suggest that partial tail loss in tadpoles diminishes jumping performance of resultant metamorphs. This effect is likely a consequence of tail-clipped tadpoles developing shorter hindlimbs as metamorphs, which is parallel to their reduced body condition. Therefore, predator attacks in the tail may be less potentially mortal than those in the head and body, but have costs in terms of an efficient antipredatory response that persist in post-metamorphic stage. This effect might compromise metamorph ability to survive subsequent predator attacks.

Studies on the impacts of variation of biotic interactions at key life cycle stages are crucial to understand the interface between ecological and developmental processes. Predators exert a major impact on prey fitness. Although direct consumption entails the greatest effect, predators can affect prey by means of other mechanisms. For instance, injuries inflicted by failed predation attempts can jeopardize prey fitness, even beyond the short-term. In anuran tadpoles, failed predation typically results in partial tail loss, which is known to reduce swimming speed. However, the potential consequences of tadpole partial tail loss after metamorphosis remain understudied. Because tail materials could be important in conforming metamorph body, we assess the effects of tadpole partial tail loss on metamorph body size in Iberian spadefoot toads Pelobates cultripes. We clipped 55% tail length of pre-tail-resorption stage anesthetized tadpoles, and compared their body size as metamorphs with anesthetized and non-anesthetized non-tail-clipped controls. Also, we tested whether tail length correlated with metamorph body size of individuals of the control groups. Tail-clipped tadpoles produced smaller metamorphs than both controls (the bdy size of metamorphs from both controls was similar), which could incur costs in mid-term survival or time to first reproduction. This effect could be particularly important in areas with introduced predators, if autochthonous tadpoles lack defenses against them. Results suggest that materials resorbed from tadpole tail tissues might be reallocated into metamorph body, according to the negative effect of shorter tails in a correlational analysis, and clipped tails in an experimental test, on metamorph body size.

Antarctica is a stressful ecosystem with few vascular plants, an ideal system to test positive interactions. Here, plants such as Deschampsia antarctica could generate more suitable micro-environmental conditions for the establishment of other plants (facilitation). We examined the co-occurrence of vascular plant species in the Antarctic Peninsula and assessed the potential nurse effect by D. antarctica on the native Colobanthus quitensis and the invasive Poa annua. We also measured the ecophysiological performance and survival of C. quitensis within and outside the canopy of D. antarctica in two study sites differing in stress levels. In addition, a survival experiment was conducted with the invasive Poa annua individuals within and outside D. antarctica individuals. In sites where present, target species co-occurred with D. antarctica in both Shetland Islands and Antarctic Peninsula. In agreement with the stress gradient hypothesis, we found evidence of facilitation between vascular Antarctic plant species. Specifically, we found that D. antarctica facilitates the native C. quitensis and the invasive P. annua and that the effect is stronger in more stressful sites. Additionally, C. quitensis distribution is compatible with an influence of either direct or indirect facilitation from D. antarctica. Facilitation between vascular plants may play a role structuring Antarctic plant communities. Thus, distribution of native species should be considered when assessing the introduction and spread of invasive species. Also, our results together with those from previous studies showed that the type and magnitude of biotic interactions may change with time and can depend on the plant traits considered.

The Iberian Peninsula is one of the European regions with the highest number of endemic species. Therefore, it is imperative to identify species populations potentially affected by variations in ecosystem functioning. Since the emergence of data processed from satellites, the possibility of carrying out studies covering both a spatial and temporal dimension has increased, providing more comprehensive information about species population dynamics and ecosystems. Primary productivity is a crucial parameter for understanding ecosystem function and services because it is the basis of the trophic chain. This study examines the spatiotemporal variation in primary productivity over a 14-year temporal series (2000–2013) through the enhanced vegetation index (EVI). We focused on the hotspots of endemic diurnal butterflies in the Iberian Peninsula and obtained data on the primary productivity dynamics at these locations as indicators to optimize further conservation efforts. Within these hotspots, statistically significant yet spatially irregular trends were found at localized sites, mostly in mountain systems (the Cantabrian Mountains, Iberian System, Sierra de Guadarrama and Sierra Nevada). At 60% of these sites, primary productivity significantly decreased. Two endemic species, the Sierra Nevada blue (Polyommatus golgus) and the Puerto del Lobo butterfly (Agriades zullichi), which are classified by the International Union for Nature Conservation (IUCN) as “Vulnerable” and “Endangered”, respectively, are present in localities where primary productivity showed a marked decline despite being within the Natura 2000 Network. The procedures developed here, which are based on consistent temporal trends of primary productivity, can serve as a tool to detect among biodiversity hotspots those locations where environmental change is unequivocal and hence further monitoring is needed.

Recently, the European Commission adopted a new strategy to halt the loss of biodiversity. Member states are expected to favor a more effective collection and redistribution of European Union (EU) funds under the current Multiannual Financial Framework for 2014–2020. Because of the large spatial variation in the distribution of biodiversity and conservation needs at the continental scale, EU instruments should ensure that countries with higher biodiversity values get more funds and resources for the conservation than other countries. Using linear regressions, we assessed the association between conservation investments and biodiversity values across member states, accounting for a variety of conservation investment indicators, taxonomic groups (including groups of plants, vertebrates, and invertebrates), and indicators of biodiversity value. In general, we found clear overall associations between conservation investments and biodiversity variables. However, some countries received more or less investment than would be expected based on biodiversity values in those countries. We also found that the extensive use of birds as unique indicators of conservation effectiveness may lead to biased decisions. Our results can inform future decisions regarding funding allocation and thus improve distribution of EU conservation funds.

[Aim]: While the contribution of abiotic factors to species distribution is well known, the geographic structure, if any, of biotic interactions within the species range is poorly understood. Most studies neglect biotic interactions when generating Species Distribution Models (SDMs) and projecting them, using future climatic scenarios, while others argue that biotic interactions may extend species tolerances to suboptimal abiotic conditions. Elucidating the extent to which biotic interactions play a role at a macro‐scale is challenging due to its inherent complexity. In this study, we characterized the independent contribution of prey abundance distributions on the Merlin's wintering distribution (Falco columbarius). Then, to examine the hypothesis that biotic interactions may counteract other suboptimal conditions, we tested for a differential importance of physical habitat characteristics and prey abundance distributions along the species’ wintering range., [Location]: Peninsular Spain., [Methods]: We modelled the Merlin's geographic distribution with Boosted Classification Trees as a function of environmental predictors (environmental model) and prey relative abundances (prey model), either separately or jointly (combined model). We tested whether the predictive success of environmental and prey models differ spatially., [Results]: Partialling out the variation into independent components we found that the prey abundance distributions explained the largest part of variation. Furthermore, the first four predictors with the highest contribution in our combined models were the abundances of prey species. Finally, our model predictions revealed a north‐to‐south increase in the importance of prey abundance distributions. Interestingly, our results suggest that biotic interactions can enable species to inhabit a wider range of suboptimal habitat conditions on range margins., [Main conclusions]: Relevant biotic interactions may not be always fully interchangeable with environmental surrogates. Abiotic factors and biotic interactions may shape species range limits and cores of distributions differently. Neglecting biotic interactions may compromise spatiotemporal transferability of SDMs, especially on species margins, and hence their applicability.

As an evolutionary force, predation increases predator fitness, whereas prey future fitness is reduced to zero. Mesopredators are subjected to pressures as both predator and prey, which could generate trade-offs between predatory and anti-predatory behaviours. We subjected larvae of the mesopredator Pleurodeles waltl newt to a potential conflict of interest between reducing predation risk and fulfilling nutritional requirements. For this, we performed an experiment with a factorial design: (1) to induce different urges as predators, individuals underwent either restricted or unrestricted feeding; and (2) to induce different urges as prey, individuals were exposed to environments with and without predator snake kairomones. We recorded activity rate, swim rate, flight initiation distance (FID) and escape speed. FID increased in the presence of kairomones, as predicted by escape theory when the costs of not fleeing are greater than those of fleeing. Escape speed increased in the presence of kairomones, but only in restricted feeding larvae, probably due to lower body weight because of reduced food intake. We detected no effect of treatment on activity or swim rates. Predation risk apparently outweighed the costs of feeding opportunities lost rather than generated a behavioural trade-off. Collectively, the data suggested a greater effect of predator avoidance than of prey acquisition.

The Iberian Peninsula is a major European region of biodiversity, as it harbours more than 30% of European endemic species. Despite a number of studies having evaluated the ability of nature reserves to protect certain taxa, there is still a lack of knowledge on how Iberian endemic fauna are represented in these reserves. We detected biodiversity hotspots of Iberian endemicity and evaluated the effectiveness of the Natura 2000 network (N2000) in representing 249 endemic species from eight animal taxonomic groups (amphibians, mammals, freshwater fishes, reptiles, water beetles, butterflies, lacewings and dung beetles). We found that only the 10% of these Iberian endemic species are considered species of community interest (i.e. species included in the Annexes of the Habitats Directive). We conducted gap analyses and null models of representativeness in N2000. Generally, N2000 is effective in its representation of Iberian endemic fauna, although we detected species and few hotspots of endemism that were still not represented. It is necessary to declare a few new protected areas, thus enhancing N2000's effectiveness in the conservation of the Iberian endemic fauna. Although the aim of N2000 is to protect species listed in the Birds and Habitats Directives, the conservation status of endemic species from one of the most important areas of Europe in terms of biodiversity, could be also a concern for the European Union. Our results are useful in the context of the recent European Commission mandate calling for a ‘fitness check’ of the Birds and Habitats Directives. This approach could be also applicable to other regions with high value of endemicity.

The two non-native grasses that have established long-term populations in Antarctica (Poa pratensis and Poa annua) were studied from a global multidimensional thermal niche perspective to address the biological invasion risk to Antarctica. These two species exhibit contrasting introduction histories and reproductive strategies and represent two referential case studies of biological invasion processes. We used a multistep process with a range of species distribution modelling techniques (ecological niche factor analysis, multidimensional envelopes, distance/entropy algorithms) together with a suite of thermoclimatic variables, to characterize the potential ranges of these species. Their native bioclimatic thermal envelopes in Eurasia, together with the different naturalized populations across continents, were compared next. The potential niche of P. pratensis was wider at the cold extremes; however, P. annua life history attributes enable it to be a more successful colonizer. We observe that particularly cold summers are a key aspect of the unique Antarctic environment. In consequence, ruderals such as P. annua can quickly expand under such harsh conditions, whereas the more stress-tolerant P. pratensis endures and persist through steady growth. Compiled data on human pressure at the Antarctic Peninsula allowed us to provide site-specific biosecurity risk indicators. We conclude that several areas across the region are vulnerable to invasions from these and other similar species. This can only be visualized in species distribution models (SDMs) when accounting for founder populations that reveal nonanalogous conditions. Results reinforce the need for strict management practices to minimize introductions. Furthermore, our novel set of temperature-based bioclimatic GIS layers for ice-free terrestrial Antarctica provide a mechanism for regional and global species distribution models to be built for other potentially invasive species.

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.

© 2015 John Wiley & Sons Ltd. Aim: Quantifying species abundances is costly, especially when many species are involved. To overcome this problem, several studies have predicted local abundances (at the sample unit level) from species occurrence distribution models (SODMs), with differences in predictive performance among studies. Surprisingly, the ability of SODM to predict regional abundances of an entire area of interest has never been tested, despite the fact that it is an essential parameter for species conservation and management. We tested whether local and regional abundances of 21 terrestrial bird species could be predicted from SODMs in an exhaustively surveyed island, and examined the variation explained by species-specific traits. Location: La Palma Island, Canary Islands. Methods: We firstly assessed two types of algorithms representing the two main families of SODMs. We built models using presence/absence (boosted classification trees) and presence/background (MaxEnt) data as a function of relevant environmental predictors and tested their ability to predict the observed local abundances. The predicted probabilities of occurrence (Pi) were translated into animal numbers (n′) using the revisited equation ni′ = -ln(1-Pi), and we obtained regional abundances (for the whole island). Results: Predictive ability of presence/absence models was superior than that of MaxEnt. At the regional level, the observed average densities of all species were highly predictable from occurrence probabilities (R2 = 93.5%), without overall overestimation or underestimation. Interspecific variation in the accuracy of predicted regional density was largely explained (R2 = 73%), with habitat breath and variation in local abundance being the traits of greatest importance. Main conclusions: Despite uncertainties associated with local predictions and the idiosyncrasies of each species, our procedures enabled us to predict regional abundances in an unbiased way. Our approach provides

The impacts of unpredictable ecological perturbations are often assessed via measurements of environmental change only after the event has occurred. Temporal series of satellite images provide a cost-effective way to gather information before ecological perturbations occur. However, in previous studies, the disturbances have neither been always centred in time in the series of the focal environmental variable nor has the relevance of the temporal coverage been explicitly tested through factorial designs. In this study, we manipulated the temporal coverage and the position of the disturbance event in the temporal series to examine whether and how the assessment is affected. Specifically, we tested the effect of the Prestige oil spill on monthly sea chlorophyll concentration and net primary productivity along the north-western Spanish coast. We designed planned comparisons through factorial analyses to test two alternative hypotheses: (1) the spill has negative consequences on phytoplankton activity and/or abundance due to physiological constraints or (2) it has positive consequences on phytoplankton abundance as a result of changes in biotic interactions. The relevance of the statistical effects was critically dependent on the temporal coverage and the position of the spill event in the temporal series. Short periods (three years) were insufficient to cover the range of variability even if the disturbance was centred in the time series. Similarly, results from longer time series (up to eight years) in which the event was temporally biased (at the beginning of the time series) also differed from those that were centred in the entire time window. Temporal series for the study of ecological impacts should be as long as necessary to encompass the temporal variability of the study systems (up to nine years in our study case), and the disturbance event should be centred in the time series to reduce potential spurious effects of temporal autocorrelation. However, our result