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161.
Multibillion dollar investments in land restoration make it critical that conservation goals are achieved cost‐effectively. Approaches developed for systematic conservation planning offer opportunities to evaluate landscape‐scale, temporally dynamic biodiversity outcomes from restoration and improve on traditional approaches that focus on the most species‐rich plantings. We investigated whether it is possible to apply a complementarity‐based approach to evaluate the extent to which an existing network of restoration plantings meets representation targets. Using a case study of woodland birds of conservation concern in southeastern Australia, we compared complementarity‐based selections of plantings based on temporally dynamic species occurrences with selections based on static species occurrences and selections based on ranking plantings by species richness. The dynamic complementarity approach, which incorporated species occurrences over 5 years, resulted in higher species occurrences and proportion of targets met compared with the static complementarity approach, in which species occurrences were taken at a single point in time. For equivalent cost, the dynamic complementarity approach also always resulted in higher average minimum percent occurrence of species maintained through time and a higher proportion of the bird community meeting representation targets compared with the species‐richness approach. Plantings selected under the complementarity approaches represented the full range of planting attributes, whereas those selected under the species‐richness approach were larger in size. Our results suggest that future restoration policy should not attempt to achieve all conservation goals within individual plantings, but should instead capitalize on restoration opportunities as they arise to achieve collective value of multiple plantings across the landscape. Networks of restoration plantings with complementary attributes of age, size, vegetation structure, and landscape context lead to considerably better outcomes than conventional restoration objectives of site‐scale species richness and are crucial for allocating restoration investment wisely to reach desired conservation goals.  相似文献   
162.
There is global concern about tropical forest degradation, in part, because of the associated loss of biodiversity. Communities and indigenous people play a fundamental role in tropical forest management and are often efficient at preventing forest degradation. However, monitoring changes in biodiversity due to degradation, especially at a scale appropriate to local tropical forest management, is plagued by difficulties, including the need for expert training, inconsistencies across observers, and lack of baseline or reference data. We used a new biodiversity remote‐sensing technology, the recording of soundscapes, to test whether the acoustic saturation of a tropical forest in Papua New Guinea decreases as land‐use intensity by the communities that manage the forest increases. We sampled soundscapes continuously for 24 hours at 34 sites in different land‐use zones of 3 communities. Land‐use zones where forest cover was fully retained had significantly higher soundscape saturation during peak acoustic activity times (i.e., dawn and dusk chorus) compared with land‐use types with fragmented forest cover. We conclude that, in Papua New Guinea, the relatively simple measure of soundscape saturation may provide a cheap, objective, reproducible, and effective tool for monitoring tropical forest deviation from an intact state, particularly if it is used to detect the presence of intact dawn and dusk choruses.  相似文献   
163.
The forests of southeastern Alaska remain largely intact and contain a substantial proportion of Earth's remaining old‐growth temperate rainforest. Nonetheless, industrial‐scale logging has occurred since the 1950s within a relatively narrow range of forest types that has never been quantified at a regional scale. We analyzed historical patterns of logging from 1954 through 2004 and compared the relative rates of change among forest types, landform associations, and biogeographic provinces. We found a consistent pattern of disproportionate logging at multiple scales, including large‐tree stands and landscapes with contiguous productive old‐growth forests. The highest rates of change were among landform associations and biogeographic provinces that originally contained the largest concentrations of productive old growth (i.e., timber volume >46.6 m3/ha). Although only 11.9% of productive old‐growth forests have been logged region wide, large‐tree stands have been reduced by at least 28.1%, karst forests by 37%, and landscapes with the highest volume of contiguous old growth by 66.5%. Within some island biogeographic provinces, loss of rare forest types may place local viability of species dependent on old growth at risk of extirpation. Examination of historical patterns of change among ecological forest types can facilitate planning for conservation of biodiversity and sustainable use of forest resources. El Uso de Patrones Históricos de Tala para Identificar Ecosistemas Talados Desproporcionadamente en Bosques Lluviosos Templados del Sureste de Alaska Albert & Schoen 11‐839  相似文献   
164.
The impacts of land‐use change on biodiversity in the Himalayas are poorly known, notwithstanding widespread deforestation and agricultural intensification in this highly biodiverse region. Although intact primary forests harbor many Himalayan birds during breeding, a large number of bird species use agricultural lands during winter. We assessed how Himalayan bird species richness, abundance, and composition during winter are affected by forest loss stemming from agriculture and grazing. Bird surveys along 12 elevational transects within primary forest, low‐intensity agriculture, mixed subsistence agriculture, and intensively grazed pastures in winter revealed that bird species richness and abundance were greatest in low‐intensity and mixed agriculture, intermediate in grazed pastures, and lowest in primary forest at both local and landscape scales; over twice as many species and individuals were recorded in low‐intensity agriculture than in primary forest. Bird communities in primary forests were distinct from those in all other land‐use classes, but only 4 species were unique to primary forests. Low‐, medium‐, and high‐intensity agriculture harbored 32 unique species. Of the species observed in primary forest, 80% had equal or greater abundance in low‐intensity agricultural lands, underscoring the value of these lands in retaining diverse community assemblages at high densities in winter. Among disturbed landscapes, bird species richness and abundance declined as land‐use intensity increased, especially in high‐intensity pastures. Our results suggest that agricultural landscapes are important for most Himalayan bird species in winter. But agricultural intensification—especially increased grazing—will likely result in biodiversity losses. Given that forest reserves alone may inadequately conserve Himalayan birds in winter, comprehensive conservation strategies in the region must go beyond protecting intact primary forests and ensure that low‐intensity agricultural lands are not extensively converted to high‐intensity pastures.  相似文献   
165.
Extinctions typically have ecological drivers, such as habitat loss. However, extinction events are also influenced by policy and management settings that may be antithetical to biodiversity conservation, inadequate to prevent extinction, insufficiently resourced, or poorly implemented. Three endemic Australian vertebrate species—the Christmas Island pipistrelle (Pipistrellus murrayi), Bramble Cay melomys (Melomys rubicola), and Christmas Island forest skink (Emoia nativitatis)—became extinct from 2009 to 2014. All 3 extinctions were predictable and probably preventable. We sought to identify the policy, management, research, and other shortcomings that contributed to their extinctions or failed to prevent them. These included a lack within national environmental legislation and policy of explicit commitment to the prevention of avoidable extinctions, lack of explicit accountability, inadequate resources for conservation (particularly for species not considered charismatic or not of high taxonomic distinctiveness), inadequate biosecurity, a slow and inadequate process for listing species as threatened, recovery planning that failed to consider the need for emergency response, inability of researchers to identify major threatening factors, lack of public engagement and involvement in conservation decisions, and limited advocacy. From these 3 cases, we recommend: environmental policy explicitly seeks to prevent extinction of any species and provides a clear chain of accountability and an explicit requirement for public inquiry following any extinction; implementation of a timely and comprehensive process for listing species as threatened and for recovery planning; reservation alone not be assumed sufficient to maintain species; enhancement of biosecurity measures; allocation of sufficient resources to undertake actions necessary to prevent extinction; monitoring be considered a pivotal component of the conservation response; research provides timely identification of factors responsible for decline and of the risk of extinction; effective dissemination of research results; advocacy by an informed public for the recovery of threatened species; and public involvement in governance of the recovery process. These recommendations should be applicable broadly to reduce the likelihood and incidence of extinctions.  相似文献   
166.
Thailand underwent a major shift in forest policy in the second half of the 1980s to promote sustainable management and control of deforestation. This paper puts this in the context of earlier changes in forest policy and analyses the underlying causes of the shift by analysing changes in the relative strength of different interest groups within the framework of a policy pressures model. Internal pressures had a stronger impact on Thai forest policy than external pressures. Protectionist groups became more numerous and more powerful in Thailand in the 1980s in relation to exploitative groups, and their rise in influence was facilitated by continuing progress in democratization and pluralization, linked to the consequences of economic development. Such political change could help to explain the apparent link between better environmental management and economic development shown in the Environmental Kuznets Curve.  相似文献   
167.
《Environmental Hazards》2013,12(4):263-277
Knowledge about natural hazard management has increased significantly since Gilbert White's seminal research in 1945, yet people are still badly affected by natural hazards. A key question remains in natural hazards research: why, when all the conditions for effective disaster risk reduction are in place, do some people not take action to reduce their risk of harm? Through a questionnaire-based study we investigated the motivating factors that led residents of the Cayman Islands to prepare for annual tropical cyclones (hurricanes). Factors that increase the likelihood of individuals preparing for hurricanes are: previous experience of major storms, having linking networks and ties, having a child under the age of 15 in the home, and residency status—expatriate residents are less likely to prepare. Factors that appear to prevent adaptive behaviour include: living close to or adjacent to the coast, recent migration to the islands, and living in rented accommodation. The findings of the survey confirm that even within societies that are well prepared for tropical cyclones, there are still sub-groups who do not engage with the preparedness process. In the case of the Cayman Islands, new migrants are the most vulnerable to tropical cyclones as they tend to fall into the demographic groups least likely to prepare for cyclones, live in locations with high levels of exposure to cyclone impacts, and interact mostly with other expatriates with no previous experience of cyclone impacts. As climate change promises to bring an increasing intensity of tropical cyclones, these findings have relevance for all islands which draw on migrant workers to support economic growth.  相似文献   
168.
An ecosystem approach to fisheries management is a widely recognized goal, but describing and measuring the effects of a fishery on an ecosystem is difficult. Ecological information on the entire catch (all animals removed, whether retained or discarded) of both species targeted by the fishery and nontarget species (i.e., bycatch) is required. We used data from the well-documented purse-seine fishery for tunas (Thunnus albacares, T. obesus, and Katsuwonus pelamis) in the eastern tropical Pacific Ocean to examine the fishery's ecological effects. Purse-seine fishing in the eastern tropical Pacific is conducted in 3 ways that differ in the amount and composition of target species and bycatch. The choice of method depends on whether the tunas are swimming alone (unassociated sets), associated with dolphins (dolphin sets), or associated with floating objects (floating-object sets). Among the fishing methods, we compared catch on the basis of weight, number of individuals, trophic level, replacement time, and diversity. Floating-object sets removed 2-3 times as much biomass as the other 2 methods, depending on how removal was measured. Results of previous studies suggest the ecological effects of floating-object sets are thousands of times greater than the effects of other methods, but these results were derived from only numbers of discarded animals. Management of the fishery has been driven to a substantial extent by a focus on reducing bycatch, although discards are currently 4.8% of total catch by weight, compared with global averages of 7.5% for tuna longline fishing and 30.0% for midwater trawling. An ecosystem approach to fisheries management requires that ecological effects of fishing on all animals removed by a fishery, not just bycatch or discarded catch, be measured with a variety of metrics.  相似文献   
169.
Using six different doses of peptone (0.25, 0.50, 0.75, 1.0, 1.25 and 1.50 gl-1) and nine different periods of inclubation (1, 2, 3, 4, 6, 8, 10, 12 and 14 days), the rates of ammonification potential (AP) were monitored in three tropical ponds of differetn ecological status, during winter and summer periods. During the winter, the AP (ammonifying bacteria) exhibited peaks on day 4 of incubation in all the test doses of peptone in all the three ponds, except in the lowest dose in eutrophic and chemically polluted pond where the peaks preceded by a day. the responses of AP to the lowest doses of substrate did not differ between summer and winter, while the AP-peaks at higher doses were delayed by 2 days in summer. the concentrations of nitrate in vitro were the inverse and direct functions of the AP and dissolved oxygen of water. at moderate dose (0.75 gl-1) of peptone, both AP and dissolved oxygen at higher doses, and by AP at the lowest dose of peptone.  相似文献   
170.
热带农业与热带旅游业的共生发展模式   总被引:4,自引:0,他引:4  
本文结合海南特区农业与旅游业资源的特点,提出热带农业与热带旅游业共生发展的理论,分析了其发展的可能性与必要性,并对共生发展的有效模式进行了探讨,提出了搞好海南特区两大产业共生发展的对策.  相似文献   
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