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991.
Sarah Cusser Christie Bahlai Scott M. Swinton G. Philip Robertson Nick M. Haddad 《Global Change Biology》2020,26(6):3715-3725
Agricultural management recommendations based on short‐term studies can produce findings inconsistent with long‐term reality. Here, we test the long‐term environmental sustainability and profitability of continuous no‐till agriculture on yield, soil water availability, and N2O fluxes. Using a moving window approach, we investigate the development and stability of several attributes of continuous no‐till as compared to conventional till agriculture over a 29‐year period at a site in the upper Midwest, US. Over a decade is needed to detect the consistent effects of no‐till. Both crop yield and soil water availability required 15 years or longer to generate patterns consistent with 29‐year trends. Only marginal trends for N2O fluxes appeared in this period. Relative profitability analysis suggests that after initial implementation, 86% of periods between 10 and 29 years recuperated the initial expense of no‐till implementation, with the probability of higher relative profit increasing with longevity. Importantly, statistically significant but misleading short‐term trends appeared in more than 20% of the periods examined. Results underscore the importance of decadal and longer studies for revealing consistent dynamics and emergent outcomes of no‐till agriculture, shown to be beneficial in the long term. 相似文献
992.
Salviae Miltiorrhizae Radix et Rhizoma (Danshen in China) and its related preparations are widely used in clinical practice due to its high medicinal value. In recent years, 1H NMR technology has made great progress and demonstrated its unique advantages in the field of botanical metabolomics. In this study, 1H NMR-based metabolomics was used to investigate the dissolution of various metabolites in Danshen as a function of ethanol concentration. 1H NMR spectroscopy of Danshen extract identified 28 metabolites including 6 sugars, 11 amino acids, 3 organic acids, 4 salvianolic acids, and 4 tanshinones. Multivariate statistical analysis was used to classify and compare various Danshen extracts. PCA and HCA were used to obtain a global overview of the similarity in the samples and two-class OPLS-DA models were established for identifying characteristic metabolites. Then, 1H-qNMR method was used to estimate the concentration of 22 metabolites, which is helpful to further describe the changes in metabolite ratios of various Danshen extracts. The result of this study laid the foundation for further biological activity research, and also provided an important reference for subsequent process research and quality control of Danshen related preparations. 相似文献
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Anna I. Roberts Sam G. B. Roberts 《Biological reviews of the Cambridge Philosophical Society》2020,95(1):51-73
Mammals living in more complex social groups typically have large brains for their body size and many researchers have proposed that the primary driver of the increase in brain size through primate and hominin evolution was the selection pressures associated with sociality. Many mammals, and especially primates, use flexible signals that show a high degree of voluntary control and these signals may play an important role in forming and maintaining social relationships between group members. However, the specific role that cognitive skills play in this complex communication, and how in turn this relates to sociality, is still unclear. The hypothesis for the communicative roots of complex sociality and cognition posits that cognitive demands behind the communication needed to form and maintain bonded social relationships in complex social settings drives the link between brain size and sociality. We review the evidence in support of this hypothesis and why key features of cognitively complex communication such as intentionality and referentiality should be more effective in forming and maintaining bonded relationships as compared with less cognitively complex communication. Exploring the link between cognition, communication and sociality provides insights into how increasing flexibility in communication can facilitate the emergence of social systems characterised by bonded social relationships, such as those found in non‐human primates and humans. To move the field forward and carry out both within‐ and among‐species comparisons, we advocate the use of social network analysis, which provides a novel way to describe and compare social structure. Using this approach can lead to a new, systematic way of examining social and communicative complexity across species, something that is lacking in current comparative studies of social structure. 相似文献
997.
Michael Smith Chantelle Jackson Nicola Palmer Bryony Palmer 《Ecological Management & Restoration》2020,21(1):42-50
Where data and information are lacking, structured expert risk assessments can provide a powerful tool to progress natural resource planning. In many situations, practitioners make informal assessments of risk within small groups that typically constitute employees. In this study, we report on three small (in terms of experts) structured expert‐based risk assessment case studies conducted by expert employees of a not‐for‐profit organisation (Australian Wildlife Conservancy) to demonstrate the utility of the approach. The case studies were carried out for three wildlife sanctuaries managed by AWC: Faure Island, Karakamia and Paruna. The likelihood that a set of direct risk factors would cause management failure for sets of important wildlife elements in the three sanctuaries was elicited from the small group of ecological experts. The analysis was couched in terms of a management aim to not lose species from each wildlife element over the management period of 25 years with current management. The experts believed, in particular, that increasing temperature and decreasing water availability associated with climate change were likely to impact significantly upon the vegetation elements and water‐reliant fauna associated with the sanctuaries. Some vegetation elements were also thought likely to be at risk of over‐grazing, unsuitable fire regimes and, in some cases, disease. In addition to predation by exotic predators at one sanctuary, the experts identified additional direct risk factors for various fauna elements associated with expected changes to the vegetation elements, including reduction in food availability, nesting habitat, and generally important life media. From the risk analyses, a preliminary conceptual model was developed to underpin monitoring and to indicate areas for possible management intervention and research. The case studies demonstrate that even in a small workplace team, structured risk assessments can be efficiently accomplished and can provide expedient and transparent information that effectively captures and aggregates the views of the experts. 相似文献
998.
Temika J. Mathieson Paul G. Close Bronte E. Van Helden Peter C. Speldewinde Sarah J. Comer 《Austral ecology》2020,45(5):596-608
A comprehensive and contemporary understanding of habitat and resource requirements has been critical to the conservation of multiple taxa and ecosystems globally. Until recently, much of the ecological knowledge that contributes to conservation priorities and strategies for the Critically Endangered western ringtail possum (Pseudocheirus occidentalis) was largely derived from decades‐old observations in peppermint (Agonis flexuosa) and marri‐jarrah (Corymbia calophylla and Eucalyptus marginanta) woodlands in the northern parts of the species range. These observations do not account for more recent evidence of their flexible use of habitat resources in other regions of its range. This may represent a significant conservation opportunity for the species through the identification of additional habitats that warrant protection. In a region where knowledge of their ecology is scarce, we used scat analysis and quantitative spotlighting to determine the diet and density of western ringtail possums in three vegetation types: peppermint, sheoak (Allocasuarina fraseriana) and marri‐eucalypt (C. calophylla, E. marginanta and Eucalyptus staerii) woodlands. Given the species’ reported dependence on peppermint woodlands and dominant canopy species for food sources, we hypothesised that western ringtail possums would be most abundant in this habitat type and that their diet would comprise the foliage of few (≤2 species) canopy species. We found western ringtail possums consumed a higher diversity of plant species than expected (8–14), exhibited dietary preference for non‐dominant canopy species and were present in all sampled vegetation types at substantially higher densities than previously recorded for the region (as high as 17 possums ha?1). Our results confirm (i) the western ringtail possum is flexible in its use of habitat resources and (ii) the significant conservation value of sheoak and marri‐eucalypt woodlands in the southernmost portion of its distribution. 相似文献
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