Plastic Responses to Temperature Versus Local Adaptation at the Cold Extreme of the Climate Gradient

Climate is a strong selection agent at high elevations, but experimental examinations of how animals exclusive of highlands cope with its variation are scarce. We analysed temperature-induced variation of early ontogenetic traits in the alpine grasshopper Chorthippus cazurroi, and compared populations from the elevational extremes of the species distribution under laboratory conditions spanning natural temperature ranges. Neither elevation of origin, nor different growing temperatures, had a direct effect on nymph body size, but both factors contributed to size at hatching indirectly, via their effect on the duration of embryo development. Large emerging nymphs had a consistently greater survival, although small and fast-developing nymphs from highlands also performed well at low temperatures. Viability selection favoured fast-developing phenotypes in conditions in which plasticity delayed development, in a typical countergradient pattern. Growth in the successive stage did not compensate for slow development at hatching, thus responses at this early stage have potential long-lasting consequences. Although phenotypic selection during early development certifies the strength of selection imposed by cold temperatures in the laboratory, elevation clines of body size did not emerge in either nymphs or the wild parental generation. Differentiation in the wild may be levelled out by fecundity selection for large sizes, drift and gene flow resulting from the fragmentation and proximity of populations, or by micro-climatic differences that reduce the likelihood of directional selection. There is therefore potential for local adaptation to temperature, but a series of conditions typical of alpine environments and ectotherms may impair, confound or constrain full differentiation along the gradient.We are grateful to M. Martini and A. Segura for their help during grasshopper rearing and to J. Moya for borrowing us HOBO sensors. We also thank Picos de Europa National Park for the permissions to capture adult grasshoppers in the study area, S. Young for editing the English, and two anonymous referees for providing useful comments on a former version of the manuscript. Funding for this study was provided by the British Ecological Society (Grant N. 4278/5250) and the Spanish Ministry of Economy and Competitiveness (CGL2011-28177, CGL2014-53899-P).Peer reviewe

Resprouting after experimental fire application and seed germination in Erica vagans

Resprouting after experimental fire treatments and the effect of light and heat on seed germination were studied in the evergreen shrub Erica vagans. Experimental fire application consisted of two levels of temperature and two levels of fire duration. The number of resprouts produced were counted after 4,9 and 12 months. Above-ground plant dry weight influenced plant survival, but not the number of resprouts produced. However, both temperature and duration of fire application showed significant effects on the number of resprouts produced. After low temperature and short application times E. vagans produced more resprouts, but did no differ from controls (plants clipped without fire treatment). Field observations showed that seedling establishment is rare both in control and burned areas. However, the seedlings were frequent in the cleared areas around experimentally burned stumps. To examine the effect of light and heat on seed germination two germination experiments were performed. Both light and heat application largely increased seed germination. Seeds heated from 80 °C to 100 °C increased their germination rates, but temperatures above that range strongly reduced the germination.Se estudió la capacidad de rebrote, después de la aplicación experimental de tratamientos de fuego, y la germinación del arbusto perennifolio Erica vagans. El fuego experimental consistió en dos niveles de temperatura y en dos niveles de tiempo de duración y se aplicó a tocones de matorrales previamente cortados. El número de rebrotes se contó después de 4,9 y 12 meses. El peso aéreo del matorral antes del experimento tuvo influencia en la supervivencia de la planta, pero no en el número de rebrotes producidos. No obstante, tanto la temperatura como el tiempo de aplicación del fuego mostraron efectos significativos sobre el número de rebrotes producidos. Los rebrotes producidos tras la aplicación de temperaturas bajas durante períodos breves fue el tratamiento que produjo mk rebrotes, pero no se diferenció de plantas control (matorral cortado pero no quemado). A pesar de que la germinación de semillas es rara en condiciones de campo, aparecieron muchas plántulas alrededor de los tocones quemados. Tanto la luz como la aplicación de tratamientos de calor, de 80°C a 100 °C, incrementaron las tasas de germinación

Pollinators and climate change

El cambio climático está ampliamente reconocido como una de las principales amenazas para la biodiversidad y los polinizadores no son ajenos a este impacto. En este trabajo, revisamos la literatura existente sobre los diferentes mecanismos mediante los cuales el cambio climático afecta a los polinizadores: (1) desplazamientos en las áreas de distribución de las especies y el subsiguiente desajuste espacial con las plantas con las que interactúan, (2) desajustes temporales entre la fenología de la floración de las plantas y la actividad de los polinizadores. Además, se consideran otros efectos del cambio climático diferentes del aumento de temperaturas, así como las potenciales interacciones del cambio climático con otros componentes de cambio global como la pérdida y fragmentación del hábitat y las invasiones biológicas. También exponemos un ejemplo sobre los efectos del cambio climático en los patrones de distribución de una comunidad de abejorros (Bombus spp.) a lo largo de un gradiente altitudinal en el norte de la península ibérica durante las últimas dos décadas. Se señalan así mismo algunas de las lagunas de conocimiento en esta área y se indican necesidades de investigaciónClimate change is widely recognized as being a major threat to biodiversity, including pollinators. In the present paper, we review the existing knowledge regarding how climate change impacts pollinators and its implication on their long-term survival. This includes: (1) spatial shifts in distribution patterns and concomitant spatial mismatches with plant-food resources, (2) temporal shifts in activity patterns and concomitant temporal mismatches with flowering plants. Furthermore, we consider other climatic effects besides global warming and potential interactions with other global change pressures such as habitat loss and fragmentation and biological invasions. We also expose an example of the impact of climate change on the spatial distribution patterns of bumblebees (Bombus spp.) along an elevation gradient in Northern Iberian Peninsula during the last two decades. Knowledge gaps and future research needs are also highlightedPeer reviewe

Local climate determines intra- and interspecific variation in sexual size dimorphism in mountain grasshopper communities

The climate is often evoked to explain broad-scale clines of body size, yet its involvement in the processes that generate size inequality in the two sexes (sexual size dimorphism) remains elusive. Here, we analyse climatic clines of sexual size dimorphism along a wide elevation gradient (i) among grasshopper species in a phylogenetically controlled scenario and (ii) within species differing in distribution and cold tolerance, to highlight patterns generated at different time scales, mainly evolutionary (among species or higher taxa) and ontogenetic or microevolutionary (within species). At the interspecific level, grasshoppers were slightly smaller and less dimorphic at high elevations. These clines were associated with gradients of precipitation and sun exposure, which are likely indicators of other factors that directly exert selective pressures, such as resource availability and conditions for effective thermoregulation. Within species, we found a positive effect of temperature and a negative effect of elevation on body size, especially on condition-dependent measures of body size (total body length rather than hind femur length) and in species inhabiting the highest elevations. In spite of a certain degree of species-specific variation, females tended to adjust their body size more often than males, suggesting that body size in females can evolve faster among species and can be more plastic or dependent on nutritional conditions within species living in adverse climates. Natural selection on female body size may therefore prevail over sexual selection on male body size in alpine environments, and abiotic factors may trigger consistent phenotypic patterns across taxonomic scales.Funding was partially provided by the Spanish Ministries of Science and Innovation (grants CGL2008-02749, CGL2009-11302 and CGL2011-28177) and Agriculture and Environment (grant 375/2011). J.C. Illera was supported by a Ramón y Cajal postdoctoral fellowship.Peer reviewe

Rebrote después de incendio e inversión reproductiva en Erica cinerea y E. vagans

Se estudió el crecimiento anual y la distribución de recursos de clones control y de rebrotes en áreas incendiadas y en zonas control en Erica vagans y E. cinerea, encontrándose que no existen diferencias significativas entre ambas especies. Sin embargo, el crecimiento de los rebrotes tras el incendio fue superior al estimado en los controles. La asignación reproductiva en el rebrote después de incendios disminuyó en ambas especies, sobre todo en E. cinerea. Los patrones de asignación reproductiva dependientes del tamaño que aparecen en los controles no se encuentran en el rebrote, lo cual sugiere una asignación reproductiva plástica.Post-fire growth and annual growth of control branches were studied in Erica vagans and E. cinerea in two northem Spain localities. The dry weight of the resprouts was greater than that of the control branches. However, neither growth of the control branches nor resprouts differed among species. Reproductive allocation did not show differences among species, but significantly decreased in burned areas, specially in E. cinerea. Reproductive allocation was size-dependent in control branches, but this pattem did not appear in the resprouts. This variations suggest a flexible reproductive strategy

Divergent responses of flagship, keystone and resource-limited bio-indicators to forest structure

Bio-indicators are often proposed to set conservation priorities in forest habitat owing to the difficulties of determining forest intrinsic ecological value. Here, we tested the efficacy of a number of potential bird indicator groups in monitoring beech Fagus sylvatica forest status by analyzing their associations with the spatial and structural variables of forest vegetation that indicate key ecological patterns and processes. The density of cavity nesting birds, indicating the presence of limited forest resources (resource-limited indicators), was influenced by tree species diversity, vertical species mingling and diameter, parameters reflecting maturity, gap-dynamic processes, as well as resource and shelter availability. Heterogeneity in shrub species composition, another parameter depending on forest dynamics, was positively associated with the occurrence of Capercaillie, a “flagship” species for forest conservation. The presence of woodpeckers, a “keystone” group that provides shelter and foraging substrate to other organisms, was positively affected by the basal area of standing dead trees that is indirectly associated with natural nutrient availability. These findings suggest that single indicators fail to provide a complete assessment of forest status, and their use in monitoring or managing forest ecosystem need to be contextualized to specific ecological patterns. The combined use of several indicators, representing various taxa, functions and life histories, appears to be preferable, and is logistically feasible if these can be surveyed together. Several indicators would likely display a wider range of sensitivities to the modification of natural processes and permit more comprehensive tracking of forest dynamics than single flagship, keystone or resource-limited indicators.The study was funded by the Environmental Agency of Asturias (Grant CN-07-174 to J.R.O.) and by the Spanish Ministry of Science and Innovation (Grants CGL2008-02749 and CGL2009-11302 to P.L and J.R.O). J.C.S. was funded by a FICYT “Severo Ochoa” fellowship.Peer reviewe

Biotic and abiotic factors modulating wild boar relative abundance in Atlantic Spain

The population dynamics of wild ungulates, particularly wild boar (Sus scrofa), are modulated by biotic (e.g. predation) and abiotic (environmental) determinants. Despite the evident potential interference of predation in the environmental patterns of wild boar population abundance, studies including both predation and abiotic factors are scarce. Here, using spatially explicit predictive models, we investigated the effects of habitat features on the relative abundance of wild boar populations and how the abundance of boars is related to frequency of Iberian wolf (Canis lupus signatus; hereafter, wolf) in the area. Wild boar relative abundance was determined by hunting bag statistics, including hunting effort-related variables (in order to avoid problems derived from modeling rates) as covariates, while wolf attacks to livestock were considered as a proxy of wolf frequency in the drive. After modeling, variation partitioning procedures were used to determine the relative importance of each factor and their overlaid effects. Our results showed that wild boar and wolf relative abundances are associated. According to previous knowledge on the wild boar ecology, we found that the species abundance is positively related to the percentage of surface occupied by mature forest and heather providing high food diversity and refuge, but these environmental variables achieved a low explanatory capacity in the models in relation to wolf frequency. The holistic approach followed in this study was attended to open new perspectives for thinking on the wolf-livestock conflict and to adequate wild boar management strategies taking into account hunting interests and natural processes.The study was funded by the Environmental Agency of Asturias (grant CN-07-174 to J.R.O.). P. Acevedo enjoyed a post-doctoral grant (SFRH/BPD/90320/2012) from Fundação para a Ciência e a Tecnologia (FCT) funded by Programa Operacional Potencial Humano (POPH)–Quadro de Referência Estratégico Nacional (QREN) from the European Social Fund and by the Portuguese Ministério da Educação e Ciência. He is currently supported by the Spanish Ministerio de Economía y Competitividad (MINECO) and Universidad de Castilla-La Mancha (UCLM) through a ‘Ramón y Cajal’ contract (RYC-2012-11970) and partly by EMIDA ERA-NET grant Aphaea (219235 FP7 ERA-NET EMIDA.Peer Reviewe

Abiotic, Biotic, and Evolutionary Control of the Distribution of C and N Isotopes in Food Webs

Ecosystem functioning depends on nutrient cycles and their responses to abiotic and biotic determinants, with the influence of evolutionary legacies being generally overlooked in ecosystem ecology. Along a broad elevation gradient characterized by shifting climatic and grazing environments, we addressed clines of plant N and C∶N content and of δ13C and δ15N in producers (herbs) and in primary (grasshoppers) and secondary (birds) consumers, both within and between species in phylogenetically controlled scenarios. We found parallel and significant intra- and interspecific trends of isotopic variation with elevation in the three groups. In primary producers, nutrient and isotope distributions had a detectable phylogenetic signal that constrained their variation along the environmental gradient. The influence of the environment could not be ascribed to any single factor, and both grazing and climate had an effect on leaf stoichiometry and, thus, on the resources available to consumers. Trends in consumers matched those in plants but often became nonsignificant after controlling for isotopic values of their direct resources, revealing direct bottom-up control and little phylogenetic dependence. By integrating ecosystem and mechanistic perspectives, we found that nutrient dynamics in food webs are governed at the base by the complex interaction between local determinants and evolutionary factors.Funding for this study was provided by “Fundación Biodiversidad,” the Spanish Ministry of Science and Innovation (grants CGL2009-11302 and CGL2011-28177), and the British Ecological Society (grant 4278/5250). J.C.I. was supported by a Ramón y Cajal postdoctoral fellowship.Peer reviewe

Gradual distance dispersal shapes the genetic structure in an alpine grasshopper

The location of the high mountains of southern Europe has been crucial in the phylogeography of most European species, but how extrinsic (topography of sky islands) and intrinsic features (dispersal dynamics) have interacted to shape the genetic structure in alpine restricted species is still poorly known. Here we investigated the mechanisms explaining the colonisation of Cantabrian sky islands in an endemic flightless grasshopper. We scrutinised the maternal genetic variability and haplotype structure, and we evaluated the fitting of two migration models to understand the extant genetic structure in these populations: Long-distance dispersal (LDD) and gradual distance dispersal (GDD). We found that GDD fits the real data better than the LDD model, with an onset of the expansion matching postglacial expansions after the retreat of the ice sheets. Our findings suggest a scenario with small carrying capacity, migration rates, and population growth rates, being compatible with a slow dispersal process. The gradual expansion process along the Cantabrian sky islands found here seems to be conditioned by the suitability of habitats and the presence of alpine corridors. Our findings shed light on our understanding about how organisms which have adapted to live in alpine habitats with limited dispersal abilities have faced new and suitable environmental conditions.British Ecological Society | Ref. 4278Ministerio de Economía y Competitividad | Ref. CGL2014-53899-PAgencia Estatal de Investigación | Ref. CGL2017-85191-PAgencia Estatal de Investigación | Ref. RYC-2015-18241Gobierno del Principado de Asturias | Ref. IDI/2018/000151Ministerio de Economía y Competitividad | Ref. CGL2011-2817

Intracellular Ca2 + deposits and catecholamine secretion by chemoreceptor cells of the rabbit carotid body

Producción CientíficaThe pívotal role of íntracellular free [Ca2+] fluctuatíons in the control of cellular functíons such as contraction and secretíon, íncludíng the release of neurotransmítters, was recognized many decades ago (see Rubín, 1982). More recently, the list of cellular functíons tríggered or modulated by the levels of Ca2+¡ has grown enormously. Addítional functíons regulated by [Ca2+)¡ include neuronal excítabílity, synaptic plastícíty, gene ex­ pressíon, cellular metabolísm, cell dívísíon and dífferentíatíon, and programmed cell dead (Míller, 1991; Clapham, 1995). Parallelíng the growth in this líst of Ca2+-controlled func­ tíons, a multíplicity of cellular mechanísms aimed at maintaining resting free [Ca2+)¡ in the range of l 00 nM for most cells has been described, allowing increases in Ca2+¡ levels that are specific in their magnitude, time course and spatial distributíon, accordíng to the cell function activated (Toescu, 1995). Since Ca2+ cannot be metabolized, cells regulate theír cytoplasmic levels of free Ca2+ through numerous bínding proteíns and influx and efflux mechanisms (Fíg 1). Ca2+ ínflux to cell cytoplasm from the extracellular milieu occurs vía voltage or receptor operated channels or vía yet ill-defined capacítatíve pathways; the Na+/Ca 2+ exchanger can also produce in sorne círcumstances net ínflux of Ca2+ (Míller, 1991; Clapham, 1995). Ca2+ ef­ flux to the extracellular space occurs against electrochemical gradíents, and thereby the pumpíng out of Ca2+ is directly (Caz+ pump) or indirectly (Na+/Ca2+) coupled to the hy­ drolysis of ATP