苏打盐碱土地区水田水盐运移模拟与预测研究

井灌种稻虽然是近年来松嫩平原西部土地苏打盐碱化治理的有效途径,但苏打盐碱地种稻改良对土壤盐分状况的长期影响,却缺乏定量化评价。作者选择该区代表性地点,通过田间观测与建立模型相结合的方法,对现有种植条件下的水田盐分动态变化进行了模拟和检验。研究发现,经过一定开垦年限土壤剖面平均含盐量下降到1.5g·kg-1左右后,在降水量正常的条件下,土壤盐分已基本达到平衡,不再随着开垦年限增加而进一步下降。相反,如遇干旱年份土壤盐分还会略有增加。需要进一步采取增加排水次数、改善土壤通透性等其它技术措施,才能使苏打盐碱地种稻改良达到更加理想的效果。     

盐胁迫对红海榄幼苗根茎叶膜保护系统的影响

红海榄(Rhizophora stylosa)属于乔木红树植物,它对不同盐度的生理反应存在着差异。本文通过对拒盐红树植物红海榄Rs在盐胁迫下各种生理反应的研究,分析了各种生理现象与盐度之间的关系,这对红树植物耐盐机理的研究打下了基础,并为中国南海岸耐盐红树树种的选育提供科学依据,也有助于从多学科研究的角度评估盐胁迫的生态重要性。通过对Rs用不同的盐度的水3个月的处理,发现Rs根、茎、叶中蛋白质质量分数随盐度的变化趋势与可溶性总糖质量分数与盐度的变化趋势相反。当盐度高于40时,Rs茎、叶的膜脂质过氧化破坏显著加强,植物体内超氧化物歧化酶(SOD)活性也明显增加,两者具有很好的相关性(R2=0.893)。随着盐度的升高,Rs各器官过氧化物酶(POD)和过氧化氢酶(CAT)活性都增强。根据实验结果,Rs能够在高盐度(50)下存活3个月。在盐度为20~30时,Rs在生理生态上表现对盐环境的适应性。当盐度高于40时,Rs的生理表现较为敏感,膜脂质氧化破坏严重。     

The Effect of Incremental Reserve Design and Changing Reservation Goals on the Long-Term Efficiency of Reserve Systems

Abstract:  Selecting reserve areas based on percentages, such as 10% or 12% of a bioregion, is common in conservation planning despite widespread admission that such percentages are arbitrary and likely to be inadequate for the conservation of all biodiversity. Reserve systems based on these relatively low percentage targets are likely to require expansion in the future, resulting in the assembly of reserve systems over many years (incremental reserve design). How then will incremental reserve design, such as increasing percentage targets over time, affect the long-term efficiency of marine reserve systems? We used South Australia as a case study to investigate how changing percentage targets affects the contribution of individual planning units to efficient reserve design. Selection frequency counts provided a measure of a planning unit's conservation value. For the majority of planning units, changing targets led to a change in their conservation value indicating, for example, that planning units identified as high-value sites at a low-percentage conservation target may be of lesser importance when targets are increased. Despite the variability in the value of individual planning units at different targets, there was no loss in efficiency from incremental design of reserve systems based on systematic methods compared with purpose-built reserve systems (i.e., the system is assembled in a single iteration). The exception was when incrementally designed systems were based on South Australia's existing marine reserve system—a system developed in an ad hoc method. The result was reserve systems that were less efficient, less compact, and larger in size. This suggests that systematic approaches have an important role for efficient reserve design when there is uncertainty about the target level of reservation .     

Assessment of Effectiveness of Protection Strategies in Tanzania Based on a Decade of Survey Data for Large Herbivores

Abstract:  Considerable controversy surrounds the effectiveness of strictly protected areas that prohibit consumptive resource use. For Tanzania we compared temporal changes in densities of large herbivores among heavily protected national parks and game reserves, partially protected game-controlled areas, and areas with little or no protection. Comparisons based on surveys conducted in the late 1980s and early 1990s versus the late 1990s and early 2000s showed three consistent patterns across the country. First, significant declines in the densities of large herbivores between these two snapshots in time overwhelmingly outnumbered significant increases in all protection categories. Second, more species fared well (increased significantly or showed no significant change) in strictly protected national parks than in areas with partial or no protection and in heavily protected game reserves relative to areas with no protection. Third, significantly more species fared poorly (densities declined or were too low to detect a decline) than fared well in areas with partial or no protection. Our results show that although heavy protection was generally more effective in maintaining large herbivore populations than partial or no protection, continued long-term monitoring is needed in Tanzania to inform managers whether large herbivores are experiencing declining population trends even within heavily protected areas .     

The Effectiveness of Iberian Protected Areas in Conserving Terrestrial Biodiversity

Abstract:  The Iberian Peninsula harbors about 50% of European plant and terrestrial vertebrate species and more than 30% of European endemic species. Despite the global recognition of its importance, the selection of protected areas has been ad hoc and the effectiveness of such choices has rarely been assessed. We compiled the most comprehensive distributional data set of Iberian terrestrial plant and vertebrate species available to date and used it to assess the degree of species representation within existing protected areas. Existing protected areas in Spain and Portugal reasonably represented the plant and animal species we considered (73–98%). Nevertheless, species of some groups (amphibians, reptiles, birds, and gymnosperms) did not accumulate in protected areas at a rate higher than expected by chance ( p > 0.05). We determined that to conserve all vertebrate and plant species in the Iberian Peninsula, at least 36 additional areas are needed. Selection of additional areas for conservation would be facilitated if such areas coincided with sites of community importance (SCI) designated under the European Commission Habitats Directive. Additional areas required for full representation of the selected plant and animal species all coincide with SCI in Spain. Nevertheless, the degree of coincidence varies between 0.3% and 74.6%, and there is a possibility that important areas for conservation occur outside the SCI. Our results support the view that current SCI can be used for prioritization of areas for conservation, but a systematic reevaluation of conservation priorities in Spain and Portugal would be necessary to ensure that effective conservation of one of European's most important biodiversity regions is achieved.     

Rethinking Community-Based Conservation

Abstract:  Community-based conservation (CBC) is based on the idea that if conservation and development could be simultaneously achieved, then the interests of both could be served. It has been controversial because community development objectives are not necessarily consistent with conservation objectives in a given case. I examined CBC from two angles. First, CBC can be seen in the context of paradigm shifts in ecology and applied ecology. I identified three conceptual shifts—toward a systems view, toward the inclusion of humans in the ecosystem, and toward participatory approaches to ecosystem management—that are interrelated and pertain to an understanding of ecosystems as complex adaptive systems in which humans are an integral part. Second, I investigated the feasibility of CBC, as informed by a number of emerging interdisciplinary fields that have been pursuing various aspects of coupled systems of humans and nature. These fields—common property, traditional ecological knowledge, environmental ethics, political ecology, and environmental history—provide insights for CBC. They may contribute to the development of an interdisciplinary conservation science with a more sophisticated understanding of social-ecological interactions. The lessons from these fields include the importance of cross-scale conservation, adaptive comanagement, the question of incentives and multiple stakeholders, the use of traditional ecological knowledge, and development of a cross-cultural conservation ethic.