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As a responsible country, China should take on heavy responsibility of energy conservation and emission reduction, and it is an inevitable choice for China to develop high-tech industries and improve the innovation efficiency of high-tech industries in order to alleviate the current environmental pressure. Therefore, this paper takes the panel data of 30 provinces in China from 2005 to 2016 as the research sample, on the basis of using DEA Global-Malmquist index to measure the innovation efficiency of high-tech industries, it constructs three spatial weight matrices, by including spatial geography, spatial economic geography nesting and innovation, and then it uses Spatial Durbin Model to empirically analyze the effect of innovation efficiency of high-tech industry on CO2 emissions in China from spatial perspective. The results indicate: firstly, in China, CO2 emissions gradually increase from 2006 to 2012, however, some provinces have declined after 2012. And CO2 emissions present a descending trend from eastern coastal area to central and western region. Secondly, affected by “warning effect”, CO2 emissions show a significant negative spatial spillover effect. Thirdly, the overall level of innovation efficiency of high-tech industries in China is not high, and its impact on CO2 emissions is not a simple linear relationship, but shows an “inverted N–shaped” curvilinear relation, and its decomposition index EC and TC also have similar characteristics. Obviously, the research in this paper provides a necessary theoretical support for China and some emerging developing countries to rational formulating and effective implementing the energy conservation and emission reduction policies.

Bien que l'on sache beaucoup de choses sur les facteurs qui contrôlent chaque composante du cycle terrestre de l'azote (N), il est moins clair comment ces facteurs affectent la disponibilité totale de l'azote, la somme des formes organiques et inorganiques potentiellement disponibles pour les micro-organismes et les plantes. Cela est particulièrement vrai pour les écosystèmes pauvres en N tels que les terres arides, qui sont très sensibles au changement climatique et aux processus de désertification pouvant entraîner la perte de nutriments du sol tels que N. Nous avons évalué la corrélation entre différents facteurs climatiques, abiotiques, végétaux et liés aux nutriments et la disponibilité de N dans les prairies semi-arides de Stipa tenacissima le long d'un large gradient d'aridité allant de l'Espagne à la Tunisie. L'aridité avait la relation la plus forte avec la disponibilité de l'azote, suggérant l'importance des contrôles abiotiques sur le cycle de l'azote dans les terres arides. L'aridité semble moduler les effets du pH, de la couverture végétale et du C organique (CO) sur la disponibilité de l'azote. Nos résultats suggèrent que les taux de transformation de l'azote, qui sont largement influencés par les variations de l'humidité du sol, ne sont pas les moteurs directs de la disponibilité de l'azote dans les prairies étudiées. Au contraire, la forte relation entre l'aridité et la disponibilité de l'azote pourrait être motivée par des effets indirects qui opèrent sur de longues échelles de temps (des décennies à des millénaires), y compris à la fois biotiques (par exemple, la couverture végétale) et abiotiques (par exemple, le CO et le pH du sol). Si ces facteurs sont en fait plus importants que les effets à court terme des précipitations sur les taux de transformation de l'azote, alors nous pourrions nous attendre à observer une diminution décalée de la disponibilité de l'azote en réponse à l'augmentation de l'aridité. Néanmoins, nos résultats suggèrent que l'augmentation de l'aridité prévue avec le changement climatique en cours réduira la disponibilité de l'azote dans le bassin méditerranéen, affectant l'absorption des nutriments végétaux et la production primaire nette dans les prairies semi-arides de cette région. Si bien se sabe mucho sobre los factores que controlan cada componente del ciclo del nitrógeno (N) terrestre, está menos claro cómo estos factores afectan la disponibilidad total de N, la suma de formas orgánicas e inorgánicas potencialmente disponibles para microorganismos y plantas. Esto es particularmente cierto para los ecosistemas pobres en N, como las tierras secas, que son altamente sensibles al cambio climático y los procesos de desertificación que pueden conducir a la pérdida de nutrientes del suelo, como N. Evaluamos cómo los diferentes factores climáticos, abióticos, vegetales y relacionados con los nutrientes se correlacionan con la disponibilidad de N en los pastizales semiáridos de Stipa tenacissima a lo largo de un amplio gradiente de aridez desde España hasta Túnez. La aridez tuvo la relación más fuerte con la disponibilidad de N, lo que sugiere la importancia de los controles abióticos en el ciclo de N en las tierras secas. La aridez pareció modular los efectos del pH, la cobertura vegetal y el C orgánico (OC) sobre la disponibilidad de N. Nuestros resultados sugieren que las tasas de transformación de N, que son impulsadas en gran medida por las variaciones en la humedad del suelo, no son los impulsores directos de la disponibilidad de N en los pastizales estudiados. Más bien, la fuerte relación entre la aridez y la disponibilidad de N podría ser impulsada por efectos indirectos que operan en escalas de tiempo largas (décadas a milenios), incluyendo tanto bióticos (por ejemplo, cobertura vegetal) como abióticos (por ejemplo, OC y pH del suelo). Si estos factores son de hecho más importantes que los efectos a corto plazo de la precipitación en las tasas de transformación de N, entonces podríamos esperar observar una disminución retardada en la disponibilidad de N en respuesta al aumento de la aridez. Sin embargo, nuestros resultados sugieren que el aumento de la aridez predicho con el cambio climático en curso reducirá la disponibilidad de N en la cuenca mediterránea, lo que afectará la absorción de nutrientes de las plantas y la producción primaria neta en los pastizales semiáridos en toda esta región. While much is known about the factors that control each component of the terrestrial nitrogen (N) cycle, it is less clear how these factors affect total N availability, the sum of organic and inorganic forms potentially available to microorganisms and plants. This is particularly true for N-poor ecosystems such as drylands, which are highly sensitive to climate change and desertification processes that can lead to the loss of soil nutrients such as N. We evaluated how different climatic, abiotic, plant and nutrient related factors correlate with N availability in semiarid Stipa tenacissima grasslands along a broad aridity gradient from Spain to Tunisia. Aridity had the strongest relationship with N availability, suggesting the importance of abiotic controls on the N cycle in drylands. Aridity appeared to modulate the effects of pH, plant cover and organic C (OC) on N availability. Our results suggest that N transformation rates, which are largely driven by variations in soil moisture, are not the direct drivers of N availability in the studied grasslands. Rather, the strong relationship between aridity and N availability could be driven by indirect effects that operate over long time scales (decades to millennia), including both biotic (e.g. plant cover) and abiotic (e.g. soil OC and pH). If these factors are in fact more important than short-term effects of precipitation on N transformation rates, then we might expect to observe a lagged decrease in N availability in response to increasing aridity. Nevertheless, our results suggest that the increase in aridity predicted with ongoing climate change will reduce N availability in the Mediterranean basin, impacting plant nutrient uptake and net primary production in semiarid grasslands throughout this region. في حين أن الكثير معروف عن العوامل التي تتحكم في كل مكون من مكونات دورة النيتروجين الأرضية (N)، إلا أنه من غير الواضح كيف تؤثر هذه العوامل على إجمالي توافر N، وهو مجموع الأشكال العضوية وغير العضوية التي يحتمل أن تكون متاحة للكائنات الحية الدقيقة والنباتات. وينطبق هذا بشكل خاص على النظم الإيكولوجية التي تعاني من فقر النيتروجين مثل الأراضي الجافة، وهي حساسة للغاية لتغير المناخ وعمليات التصحر التي يمكن أن تؤدي إلى فقدان مغذيات التربة مثل النيتروجين. قمنا بتقييم كيفية ارتباط العوامل المناخية واللاأحيائية والنباتية والمغذيات المختلفة بتوافر النيتروجين في المراعي شبه القاحلة على طول تدرج جفاف واسع من إسبانيا إلى تونس. كان للجفاف أقوى علاقة بتوافر النيتروجين، مما يشير إلى أهمية الضوابط اللاأحيائية في دورة النيتروجين في الأراضي الجافة. يبدو أن الجفاف يعدل تأثيرات الأس الهيدروجيني والغطاء النباتي و C العضوي (OC) على توافر N. تشير نتائجنا إلى أن معدلات تحول N، التي تحركها إلى حد كبير الاختلافات في رطوبة التربة، ليست هي الدوافع المباشرة لتوافر N في الأراضي العشبية المدروسة. بدلاً من ذلك، يمكن أن تكون العلاقة القوية بين الجفاف وتوافر N مدفوعة بالتأثيرات غير المباشرة التي تعمل على نطاقات زمنية طويلة (من عقود إلى آلاف السنين)، بما في ذلك كل من الحيوية (مثل الغطاء النباتي) واللاأحيائية (مثل OC التربة ودرجة الحموضة). إذا كانت هذه العوامل في الواقع أكثر أهمية من الآثار قصيرة الأجل لهطول الأمطار على معدلات تحول N، فقد نتوقع ملاحظة انخفاض متأخر في توافر N استجابة لزيادة الجفاف. ومع ذلك، تشير نتائجنا إلى أن الزيادة في القحولة المتوقعة مع تغير المناخ المستمر ستقلل من توافر N في حوض البحر الأبيض المتوسط، مما يؤثر على امتصاص المغذيات النباتية وصافي الإنتاج الأولي في المراعي شبه القاحلة في جميع أنحاء هذه المنطقة.

The aesthetic appreciation of natural places is one of the most fundamental ways in which people relate to their environment. It provides wellbeing, an opportunity for recreation and reflection, a sense of place, and cultural enrichment. It also motivates people to take care of natural places and to conserve them for current and future appreciation. Aesthetically valuable places also support significant economic activity. However, there is little guidance available to assist environmental managers and policy-makers to consider and integrate aesthetic values into decision-making processes. In this study, we present an approach for developing robust and practical indicators of aesthetic value to enable environmental managers to consider, assess and report on aesthetic condition and trend. We demonstrate its utility using the case of the Great Barrier Reef, a region currently undergoing significant social, economic and environmental change and an area formally protected, in part, for its aesthetic values. A qualitative scoping study with 30 key informants identified over 180 potential qualities contributing to reef aesthetics. We tested five for their utility in capturing key aspects of the coral reef aesthetic: (i) coral cover, (ii) coral pattern, (iii) coral topography, (iv) fish abundance, and (v) visibility. We asked 1,417 online Australians to aesthetically rate 50 out of 181 underwater coral reef images that varied in relation to these five attributes. Coral topography, fish abundance, and visibility were significantly correlated with aesthetic ratings, whilst coral cover and coral pattern were not. We also tested for demographic patterns in aesthetic ratings. Our pilot study has demonstrated that readily measurable characteristics of coral reefs can provide useful indicators of aesthetic quality, opening up opportunities for coral reef managers and policymakers to assess and track changes in aesthetics in ways that are relevant to the public. There is considerable scope to further advance capacity for monitoring and managing aesthetic values of coral reefs through additional research that resolves nuances in the meanings associated with aesthetics in coral reef settings.

More than 60% of the total area of tree plantations in China is in subtropical, and over 70% of subtropical plantations consist of pure stands of coniferous species. Because of the poor ecosystem services provided by pure coniferous plantations and the ecological instability of these stands, a movement is under way to promote indigenous broadleaf plantation cultivation as a promising alternative. However, little is known about the carbon (C) stocks in indigenous broadleaf plantations and their dependence on stand age. Thus, we studied above- and below-ground biomass and C stocks in a chronosequence of Mytilaria laosensis plantations in subtropical China; stands were 7, 10, 18, 23, 29 and 33 years old. Our assessments included tree, shrub, herb and litter layers. We used plot-level inventories and destructive tree sampling to determine vegetation C stocks. We also measured soil C stocks by analyses of soil profiles to 100 cm depth. C stocks in the tree layer dominated the above-ground ecosystem C pool across the chronosequence. C stocks increased with age from 7 to 29 years and plateaued thereafter due to a reduction in tree growth rates. Minor C stocks were found in the shrub and herb layers of all six plantations and their temporal fluctuations were relatively small. C stocks in the litter and soil layers increased with stand age. Total above-ground ecosystem C also increased with stand age. Most increases in C stocks in below-ground and total ecosystems were attributable to increases in soil C content and tree biomass. Therefore, considerations of C sequestration potential in indigenous broadleaf plantations must take stand age into account.

Tidal habitats host a diversity of species and provide hydrological services such as shoreline protection and nutrient attenuation. Accretion of sediment and biomass enables tidal marshes and swamps to grow vertically, providing a degree of resilience to rising sea levels. Even if accelerating sea level rise overcomes this vertical resilience, tidal habitats have the potential to migrate inland as they continue to occupy land that falls within the new tide range elevations. The existence of developed land inland of tidal habitats, however, may prevent this migration as efforts are often made to dyke and protect developments. To test the importance of inland migration to maintaining tidal habitat abundance under a range of potential rates of sea level rise, we developed a spatially explicit elevation tracking and habitat switching model, dubbed the Marsh Accretion and Inundation Model (MAIM), which incorporates elevation-dependent net land surface elevation gain functions. We applied the model to the metropolitan Washington, DC region, finding that the abundance of small National Park Service units and other public open space along the tidal Potomac River system provides a refuge to which tidal habitats may retreat to maintain total habitat area even under moderate sea level rise scenarios (0.7 m and 1.1 m rise by 2100). Under a severe sea level rise scenario associated with ice sheet collapse (1.7 m by 2100) habitat area is maintained only if no development is protected from rising water. If all existing development is protected, then 5%, 10%, and 40% of the total tidal habitat area is lost by 2100 for the three sea level rise scenarios tested.

Root lifespan is an important trait that determines plants' ability to acquire and conserve soil resources. There have been several studies investigating characteristics of root lifespan of both woody and herbaceous species. However, most of the studies have focused on non-clonal plants, and there have been little data on root lifespan for clonal plants that occur widely in temperate grasslands.We investigated the effects of rhizome severing on overall root lifespan of Leymus chinensis, a clonal, dominant grass species in the temperate steppe in northern China, in a 2-year field study using modified rhizotron technique. More specifically, we investigated the effects of rhizome severing on root lifespan of roots born in different seasons and distributed at different soil depths. Rhizome severing led to an increase in the overall root lifespan from 81 to 103 days. The increase in root lifespan exhibited spatial and temporal characteristics such that it increased lifespan for roots distributed in the top two soil layers and for roots born in summer and spring, but it had no effect on lifespan of roots in the deep soil layer and born in autumn. We also examined the effect of rhizome severing on carbohydrate and N contents in roots, and found that root carbohydrate and N contents were not affected by rhizome severing. Further, we found that root lifespan of Stipa krylovii and Artemisia frigida, two dominant, non-clonal species in the temperate steppe, was significantly longer (118 d) than that of L. chinensis (81 d), and this value became comparable to that of L. chinensis under rhizome severing (103 d).We found that root lifespan in dominant, clonal L. chinensis was shorter than for the dominant, non-clonal species of S. krylovii and A. frigida. There was a substantial increase in the root lifespan of L. chinensis in response to severing their rhizomes, and this increase in root lifespan exhibited temporal and spatial characteristics. These findings suggest that the presence of rhizomes is likely to account for the observed short lifespan of clonal plant species in the temperate steppe.