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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