• Energy Research
• biological sciences close
• 15. Life on land close
• CN close
• FR close

Forest soil acidification caused by acid deposition is a serious threat to the forest ecosystem. To investigate the liming effects of biomass ash (BA) and alkaline slag (AS) on the acidic topsoil and subsoil, a three-year field experiment under artificial Masson pine was conducted at Langxi, Anhui province in Southern China. The surface application of BA and AS significantly increased the soil pH, and thus decreased exchangeable acidity and active Al in the topsoil. Soil exchangeable Ca2+ and Mg2+ in topsoil were significantly increased by the surface application of BA and AS, while an increase in soil exchangeable K+ was only observed in BA treatments. The soil acidity and active Al in subsoil were decreased by the surface application of AS. Compared with the control, soluble monomeric and exchangeable Al in the subsoil was decreased by 38.0% and 29.4% after 3 years of AS surface application. There was a minimal effect on soluble monomeric and exchangeable Al after the application of BA. The soil exchangeable Ca2+ and Mg2+ in the subsoil increased respectively by 54% and 141% after surface application of 10 t ha-1 AS. The decrease of soil active Al and increase of base cations in subsoil were mainly attributed to the high migration capacity of base cations in AS. In conclusion, the effect of surface application of AS was superior to BA in ameliorating soil acidity and alleviating soil Al toxicity in the subsoil of this Ultisol.

AbstractAcross southern China, Moso bamboo has been encroaching on most neighboring secondary broad-leaved forests and/or coniferous plantations, leading to the land cover changes that alter abiotic and biotic conditions. Little is known about how this conversion alters soil carbon (C) and nitrogen (N). We selected three sites, each with three plots arrayed along the bamboo encroachment pathway: moso bamboo forest (BF); transition zone, mixed forest plots (MF); and broad-leaved forest (BLF), and examined how bamboo encroachment affects soil organic C (SOC), soil total N, microbial biomass C (MBC), microbial biomass N (MBN), water-soluble organic C (WSOC), and water-soluble organic N (WSON) in three forests. Over nine years, moso bamboo encroachment leads to a decrease in SOC and total soil N, an increase in MBC and WSOC, and a decrease in MBN and WSON. Changes in soil C and N occurred mainly in the topsoil. We conclude that moso bamboo encroachment on broadleaved forest not only substantially altered soil C and N pools, but also changed the distribution pattern of C and N in the studied forest soils. Continued bamboo encroachment into evergreen broadleaved forests seems likely to lead to net CO2 emissions to the atmosphere as ecosystem C stocks decline.

Abstract Although wind power is a promising source of renewable energy, previous studies have focused on uncovering species and abundance decreases caused by wind farms. However, very few studies focus on collision risk of onshore wind farms in relation to birds’ movements which are the important indicators for balancing wind energy development and biodiversity conservation. Here, birds’ movement were recorded by combining 15 ducks’ satellite tracking and six field surveys to assess collision risks in Yangtze River Mouth, the wintering site for migratory waterbirds along the East Asian–Australasian Flyway. It is found that distances between ducks’ locations and nearest wind turbines in middle and later wintering periods were significantly higher than during early period. Besides, ducks inside wind farm tended to fly outside turbine rotor height range (45–135 m: between lowest and highest points the rotor tips) within 300 m from the dyke where the turbines were located, thus decreasing their collision risk. Ducks also tended to fly below the minimum rotor tip height (< 45 m) when the turbines were rotating. These results suggest that ducks adopt behavioural avoidance strategies in response to wind farms, and turning off turbines to reduce collision risks may be unnecessary.

AbstractForest growth is sensitive to interannual climatic change in the alpine treeline ecotone (ATE). Whether the alpine treeline ecotone shares a similar pattern of forest growth with lower elevational closed forest belt (CFB) under changing climate remains unclear. Here, we reported an unprecedented acceleration ofPicea schrenkianaforest growth since 1960s in theATEof Tianshan Mountains, northwestern China by a stand‐total sampling along six altitudinal transects with three plots in each transect: one from theATEbetween the treeline and the forest line, and the other two from theCFB. All the sampledP.schrenkianaforest patches show a higher growth speed after 1960 and, comparatively, forest growth in theCFBhas sped up much slower than that in theATE. The speedup of forest growth at theATEis mainly accounted for by climate factors, with increasing temperature suggested to be the primary driver. Stronger water deficit as well as more competition withinthe CFBmight have restricted forest growth there more than that within theATE, implying biotic factors were also significant for the accelerated forest growth in theATE, which should be excluded from simulations and predictions of warming‐induced treeline dynamics.

A Bayesian network model was developed to assess the combined influence of nutrient conditions and climate on the occurrence of cyanobacterial blooms within lakes of diverse hydrology and nutrient supply. Physicochemical, biological, and meteorological observations were collated from 20 lakes located at different latitudes and characterized by a range of sizes and trophic states. Using these data, we built a Bayesian network to (1) analyze the sensitivity of cyanobacterial bloom development to different environmental factors and (2) determine the probability that cyanobacterial blooms would occur. Blooms were classified in three categories of hazard (low, moderate, and high) based on cell abundances. The most important factors determining cyanobacterial bloom occurrence were water temperature, nutrient availability, and the ratio of mixing depth to euphotic depth. The probability of cyanobacterial blooms was evaluated under different combinations of total phosphorus and water temperature. The Bayesian network was then applied to quantify the probability of blooms under a future climate warming scenario. The probability of the “high hazardous” category of cyanobacterial blooms increased 5% in response to either an increase in water temperature of 0.8°C (initial water temperature above 24°C) or an increase in total phosphorus from 0.01 mg/L to 0.02 mg/L. Mesotrophic lakes were particularly vulnerable to warming. Reducing nutrient concentrations counteracts the increased cyanobacterial risk associated with higher temperatures.

Alpine and arctic lemming populations appear to be highly sensitive to climate change, and when faced with warmer and shorter winters, their well-known high-amplitude population cycles may collapse. Being keystone species in tundra ecosystems, changed lemming dynamics may convey significant knock-on effects on trophically linked species. Here, we analyse long-term (1988–2010), community-wide monitoring data from two sites in high-arctic Greenland and document how a collapse in collared lemming cyclicity affects the population dynamics of the predator guild. Dramatic changes were observed in two highly specialized lemming predators: snowy owl and stoat. Following the lemming cycle collapse, snowy owl fledgling production declined by 98 per cent, and there was indication of a severe population decline of stoats at one site. The less specialized long-tailed skua and the generalist arctic fox were more loosely coupled to the lemming dynamics. Still, the lemming collapse had noticeable effects on their reproductive performance. Predator responses differed somewhat between sites in all species and could arise from site-specific differences in lemming dynamics, intra-guild interactions or subsidies from other resources. Nevertheless, population extinctions and community restructuring of this arctic endemic predator guild are likely if the lemming dynamics are maintained at the current non-cyclic, low-density state.

Arbuscular mycorrhizal (AM) fungi play key roles in plant nutrition and plant productivity. AM fungal responses to either plant identity or fertilization have been investigated. However, the interactive effects of different plant species and fertilizer types on these symbiotic fungi remain poorly understood. We evaluated the effects of the factorial combinations of plant identity (grasses Avena sativa and Elymus nutans and legume Vicia sativa) and fertilization (urea and sheep manure) on AM fungi following 2-year monocultures in a sown pasture field study. AM fungal extraradical hyphal density was significantly higher in E. nutans than that in A. sativa and V. sativa in the unfertilized control and was significantly increased by urea and manure in A. sativa and by manure only in E. nutans, but not by either fertilizers in V. sativa. AM fungal spore density was not significantly affected by plant identity or fertilization. Forty-eight operational taxonomic units (OTUs) of AM fungi were obtained through 454 pyrosequencing of 18S rDNA. The OTU richness and Shannon diversity index of AM fungi were significantly higher in E. nutans than those in V. sativa and/or A. sativa, but not significantly affected by any fertilizer in all of the three plant species. AM fungal community composition was significantly structured directly by plant identity only and indirectly by both urea addition and plant identity through soil total nitrogen content. Our findings highlight that plant identity has stronger influence than fertilization on belowground AM fungal community in this converted pastureland from an alpine meadow.

Combler le fossé entre les prévisions des modèles climatiques à échelle grossière et la réalité climatique à échelle fine des espèces est un enjeu clé de la recherche en biologie du changement climatique. Bien qu'il soit maintenant bien connu que la plupart des organismes ne connaissent pas les conditions climatiques enregistrées dans les stations météorologiques, il existe peu d'informations sur les écarts entre les microclimats et les températures interpolées mondiales utilisées dans les modèles de répartition des espèces, et leurs conséquences sur les performances des organismes. Pour résoudre ce problème, nous avons examiné l'hétérogénéité spatio-temporelle à échelle fine des températures de l'air, du couvert végétal et du sol des paysages agricoles des Andes équatoriennes et les avons comparés aux prévisions des grilles climatiques interpolées mondiales. Des séries temporelles de températures ont été mesurées dans l'air, la canopée et le sol pour 108 localités à trois altitudes et analysées à l'aide de la transformée de Fourier. Les écarts entre les températures locales et les grilles interpolées mondiales et leurs implications pour la performance des ravageurs ont ensuite été cartographiés et analysés à l'aide de la boîte à outils statistique SIG. Nos résultats ont montré que les prévisions globales interpolées surestiment de 77,5±10 % et sous-estiment de 82,1±12 % les températures locales minimales et maximales de l'air enregistrées dans la grille étudiée. Des modifications supplémentaires de la température de l'air local étaient dues au tamponnage thermique du couvert végétal (de − 2,7°K pendant la journée à 1,3°K pendant la nuit) et des sols (de −4,9°K pendant la journée à 6,7°K pendant la nuit) avec un effet significatif de la phénologie des cultures sur l'effet tampon. Ces écarts entre les températures interpolées et locales ont fortement affecté les prévisions de la performance d'un ravageur ectothermique des cultures, car les températures interpolées prédisaient des taux de croissance des ravageurs 2,3 à 4,3 fois inférieurs à ceux prédits par les températures locales. Cette étude fournit des informations quantitatives sur la limitation des données climatiques à échelle grossière pour capturer la réalité de l'environnement climatique vécu par les organismes vivants. Dans les régions très hétérogènes telles que les montagnes tropicales, il convient donc de faire preuve de prudence lors de l'utilisation de modèles mondiaux pour déduire des processus biologiques à l'échelle locale. Cerrar la brecha entre las predicciones de los modelos climáticos a escala gruesa y la realidad climática a escala fina de las especies es un tema clave de la investigación en biología del cambio climático. Si bien ahora es bien sabido que la mayoría de los organismos no experimentan las condiciones climáticas registradas en las estaciones meteorológicas, hay poca información sobre las discrepancias entre los microclimas y las temperaturas globales interpoladas utilizadas en los modelos de distribución de especies, y sus consecuencias para el rendimiento de los organismos. Para abordar este problema, examinamos la heterogeneidad espaciotemporal a escala fina en las temperaturas del aire, el dosel de los cultivos y el suelo de los paisajes agrícolas en los Andes ecuatorianos y los comparamos con las predicciones de las redes climáticas interpoladas globales. Las series temporales de temperatura se midieron en aire, dosel y suelo para 108 localidades a tres altitudes y se analizaron mediante la transformada de Fourier. Las discrepancias entre las temperaturas locales frente a las redes interpoladas globales y sus implicaciones para el rendimiento de las plagas se mapearon y analizaron utilizando una caja de herramientas estadísticas SIG. Nuestros resultados mostraron que las predicciones interpoladas globales sobreestiman en un 77.5±10% y subestiman en un 82.1±12% las temperaturas mínimas y máximas locales del aire registradas en la cuadrícula estudiada. Las modificaciones adicionales de las temperaturas locales del aire se debieron al amortiguamiento térmico de las copas de las plantas (de -2,7 ° K durante el día a 1,3 ° K durante la noche) y los suelos (de -4,9 ° K durante el día a 6,7 ° K durante la noche) con un efecto significativo de la fenología de los cultivos en el efecto amortiguador. Estas discrepancias entre las temperaturas interpoladas y locales afectaron fuertemente las predicciones del rendimiento de una plaga de cultivo ectotérmico, ya que las temperaturas interpoladas predijeron tasas de crecimiento de plagas 2.3–4.3 veces más bajas que las predichas por las temperaturas locales. Este estudio proporciona información cuantitativa sobre la limitación de los datos climáticos a escala aproximada para capturar la realidad del entorno climático experimentado por los organismos vivos. Por lo tanto, en regiones altamente heterogéneas como las montañas tropicales, se debe tener precaución al utilizar modelos globales para inferir procesos biológicos a escala local. Bridging the gap between the predictions of coarse-scale climate models and the fine-scale climatic reality of species is a key issue of climate change biology research. While it is now well known that most organisms do not experience the climatic conditions recorded at weather stations, there is little information on the discrepancies between microclimates and global interpolated temperatures used in species distribution models, and their consequences for organisms' performance. To address this issue, we examined the fine-scale spatiotemporal heterogeneity in air, crop canopy and soil temperatures of agricultural landscapes in the Ecuadorian Andes and compared them to predictions of global interpolated climatic grids. Temperature time-series were measured in air, canopy and soil for 108 localities at three altitudes and analysed using Fourier transform. Discrepancies between local temperatures vs. global interpolated grids and their implications for pest performance were then mapped and analysed using GIS statistical toolbox. Our results showed that global interpolated predictions over-estimate by 77.5±10% and under-estimate by 82.1±12% local minimum and maximum air temperatures recorded in the studied grid. Additional modifications of local air temperatures were due to the thermal buffering of plant canopies (from −2.7°K during daytime to 1.3°K during night-time) and soils (from −4.9°K during daytime to 6.7°K during night-time) with a significant effect of crop phenology on the buffer effect. This discrepancies between interpolated and local temperatures strongly affected predictions of the performance of an ectothermic crop pest as interpolated temperatures predicted pest growth rates 2.3–4.3 times lower than those predicted by local temperatures. This study provides quantitative information on the limitation of coarse-scale climate data to capture the reality of the climatic environment experienced by living organisms. In highly heterogeneous region such as tropical mountains, caution should therefore be taken when using global models to infer local-scale biological processes. يعد سد الفجوة بين تنبؤات النماذج المناخية ذات النطاق الخشن والواقع المناخي الدقيق للأنواع قضية رئيسية في أبحاث البيولوجيا المتعلقة بتغير المناخ. في حين أنه من المعروف الآن أن معظم الكائنات الحية لا تعاني من الظروف المناخية المسجلة في محطات الطقس، إلا أن هناك القليل من المعلومات حول التناقضات بين المناخات الدقيقة ودرجات الحرارة العالمية المستكملة المستخدمة في نماذج توزيع الأنواع، وعواقبها على أداء الكائنات الحية. لمعالجة هذه المشكلة، قمنا بفحص عدم التجانس الزماني المكاني الدقيق في الهواء ومظلة المحاصيل ودرجات حرارة التربة للمناظر الطبيعية الزراعية في جبال الأنديز الإكوادورية وقارناها بتنبؤات الشبكات المناخية العالمية المستكملة. تم قياس السلاسل الزمنية لدرجة الحرارة في الهواء والمظلة والتربة لـ 108 موقعًا على ثلاثة ارتفاعات وتم تحليلها باستخدام تحويل فورييه. ثم تم رسم خرائط التناقضات بين درجات الحرارة المحلية مقابل الشبكات العالمية المستكملة وآثارها على أداء الآفات وتحليلها باستخدام مجموعة الأدوات الإحصائية لنظم المعلومات الجغرافية. أظهرت نتائجنا أن التنبؤات العالمية المستكملة تزيد عن التقديرات بنسبة 77.5±10 ٪ وتقل عن التقديرات بنسبة 82.1±12 ٪ من الحد الأدنى المحلي والحد الأقصى لدرجات حرارة الهواء المسجلة في الشبكة المدروسة. كانت التعديلات الإضافية في درجات حرارة الهواء المحلية بسبب التخزين المؤقت الحراري لمظلات النباتات (من - 2.7 درجة كلفن خلال النهار إلى 1.3 درجة كلفن خلال الليل) والتربة (من - 4.9 درجة كلفن خلال النهار إلى 6.7 درجة كلفن خلال الليل) مع تأثير كبير لظاهرة المحاصيل على تأثير العازل. أثرت هذه التناقضات بين درجات الحرارة المستكملة والمحلية بشدة على التنبؤات بأداء آفة المحاصيل خارجة الحرارة حيث تنبأت درجات الحرارة المستكملة بمعدلات نمو الآفات 2.3–4.3 مرة أقل من تلك التي تنبأت بها درجات الحرارة المحلية. توفر هذه الدراسة معلومات كمية عن محدودية البيانات المناخية ذات النطاق الخشن لالتقاط واقع البيئة المناخية التي تعاني منها الكائنات الحية. في المناطق غير المتجانسة للغاية مثل الجبال الاستوائية، يجب توخي الحذر عند استخدام النماذج العالمية لاستنتاج العمليات البيولوجية على المستوى المحلي.