995 resultados para Harrison, Frederic,
Resumo:
Forests, and particularly those where native and mixed species are gown, provide a variety of non-wood values, important among which are recreation and environmental services. Substantial progress has been made in recent years in estimating economic values on these services. A considerable amount of research on forest values has been carried out recently in tropical and sub-tropical eastern Australia, some of which is reported in the following papers. The need for estimates of non-wood forest benefits is apparent, and it is clear that further development of techniques and a greater understanding of the way these values can be integrated into public-sector decision making is required.
Resumo:
The authors discuss the regulation of rural land use and compensation for property-rights restrictions, both of which appear to have become more commonplace in recent years but also more contested. The implications of contemporary theories in relation to this matter are examined, including: the applicability of new welfare economics; the relevance of the neoclassical theory of politics; and the implications of contemporary theories of social conflict resolution and communication. Examination of examples of Swiss and Australian regulation of the use of rural properties, and the ensuing conflicts, reveals that many decisions reflect a mixture of these elements. Rarely, if ever, are social decisions in this area made solely on the basis of welfare economics, for instance social cost-benefit analysis. Only some aspects of such decisions can be explained by the neoclassical theory of politics. Theories of social conflict resolution suggest why, and in what way, approaches of discourse and participation may resolve conflicts regarding regulation and compensation. These theories and their practical application seem to gain in importance as opposition to government decisions increases. The high degree of complexity of most conflicts concerning regulation and compensation cannot be tackled with narrow economic theories. Moreover, the Swiss and Australian examples show that approaches involving conflict resolution may favour environmental standards.
Resumo:
Riparian vegetation can be an effective measure for preventing degradation of streambanks and riparian areas. However, riparian revegetation imposes large costs on landholders associated with tree establishment and removal of land from cropping, while providing benefits to downstream landholders, fishers, the local community and environmentalists. Appropriate policy instruments are required to promote sustainable and balanced use of riparian zones. This article analyses the capacity of existing legislation and other instruments to promote restoration of degraded riparian zones on private land. The role of legislation. economic instruments, community engagement and extension programs, in persuading landholders to revegetate riparian areas and improve riparian vegetation cover; is examined in the context ofa small degraded catchment in an intensive farming area in tropical north Queensland. It is found that while legislation and regulations can control undesirable modification of riparian areas, in general they are unable to make a useful contribution to restoration of these areas; incentives and assistance measures appear to offer greater potential.
Resumo:
Genetic diversity in Cassia brewsteri (F. Muell.) F. Muell. ex Benth. was assessed with Randomly Amplified DNA Fingerprints (RAFs). Thirty accessions of C. brewsteri collected from throughout its natural distribution were analysed with three random decamer primers, along with three accessions of C. tomentella (Benth.) Domin and a single accession of each of C. queenslandica C. T. White and C. marksiana (F. M. Bailey) Domin. The three primers yielded a reproducible amplification profile of 265 scorable polymorphic fragments for the 35 accessions. These molecular markers were used to calculate Nei and Li similarity coefficients between each pair of individuals. A matrix of dissimilarity of each pair of individuals was examined by multidimensional scaling (MDS). The analysis supports the division of C. brewsteri into two subspecies and the suggestion that intergradation of C. brewsteri and C. tomentella can occur where the distributions of these species meet.
Resumo:
It has been established that modern humans were living in the Levant and Africa ca. 100 ka ago. Hitherto, this has contrasted with the situation in China where no unequivocal specimens of this species have been securely dated to more than 30 ka. Here we present the results of stratigraphic studies and U-series dating of the Tongtianyan Cave, the discovery site of the Liujiang hominid, which represents one of the few well-preserved fossils of modern Homo sapiens in China. The human fossils are inferred to come from either a refilling breccia or a primarily deposited gravel-bearing sandy clay layer. In the former case, which is better supported, the fossils would date to at least similar to 68 ka, but more likely to similar to 111-139 ka. Alternatively, they would be older than, similar to 153 ka. Both scenarios would make the Liujiang hominid one of the earliest modem humans in East Asia, possibly contemporaneous with the earliest known representatives from the Levant and Africa. Parallel studies on other Chinese localities have provided supporting evidence for the redating of Liujiang, which may have important implications for, the origin of modem humans. (C) 2002 Elsevier Science Ltd. All rights reserved.