Live coral trade impacts on the mushroom coral Heliofungia actiniformis in Indonesia: Potential future management approaches

The poorly regulated aquarium trade in live corals poses yet another threat to fragile coral reef ecosystems. The Indonesian authorities routinely allocate some of the highest trade quotas in South Sulawesi to Heliofungia actiniformis despite a lack of data on the impacts of current collection practices on this species. Semi-structured interviews with fishermen and in situ surveys revealed a size-selective fishery towards small polyps. This resulted in a shift of size-frequency distributions, and reduced overall abundances at harvested sites. Total mortality rates calculated using a catch curve approach at harvested sites were significantly higher compared to those known from unharvested sites for polyps sized 0-11 cm. Recorded exploitation rates were 0.1 and 0.7 for polyps sized 0-4 cm and 4-11 cm respectively. The application of a utility per recruit approach, calculated with a Thompson and Bell model, revealed maximum potential economic yield to occur at a size of 5 cm, corresponding to an age of 5 years. This is 5 years before the attainment of reproductive maturity, and 15 years before the attainment of maximum biomass yield per recruit. A predictive model indicated the need for a 5 cm size limit to curb economic overfishing, and protect attached anthocauli stalks capable of maintaining the trade through continued asexual reproduction. In addition, a reduction of exploitation rates for polyps in the 4-11 cm size bracket to 0.5 is urgently needed. Calculations reveal that this would in fact be possible without lowering current profits. Achieving long term sustainability will in addition to a reduction of harvest quotas necessitate an effective protection of spawning stocks through stricter enforcement of existing marine protected areas.     

昆虫在医药和保健品领域的应用

综述了当前我国药用、保健昆虫的开发、利用和研究现状,分析了昆虫在医药、保健品领域应用的有关问题,提出了具体的解决措施,展望了其发展前景.     

“公司＋农户”模式违约机理及影响因素分析——基于渠道权力理论的角度

＂公司＋农户＂模式是我国农业产业化中采用率较高的农产品生产组织模式,但在实践中该模式违约率居高不下。现有的研究文献主要是从新制度经济学的角度对＂公司＋农户＂模式的违约问题进行研究。从渠道权力理论的视角探讨该模式的违约机理和影响因素,从与对方交换关系中获得效用的大小、替代关系的多少和替代成本的高低等方面进行分析,可知＂公司＋农户＂模式中契约关系从签订开始就带有一定的脆弱性。要克服＂公司＋农户＂模式中契约的脆弱性,就要扩大契约市场均衡区间,减少市场上的替代关系,提高替代成本,以此提升公司与农户合作关系的稳定性。     

基于效用函数的农户灌溉耗水量分析

使用水分生产函数及效用函数的拟可加性定理,证明在按灌溉面积计价的方式下,农户倾向于选择灌溉更多的水,这就使水价失去了价格的杠杆作用,无法使水资源得到有效配置。     

夏洛来公牛繁殖性能及利用年限观察

对夏洛来公牛繁殖性能的分析表明：初采精以２０月龄为宜。采精利用以３～５岁龄精液产量、质量最好,６岁后呈下降趋势。一年中春季精液量多质佳,冬季次之,夏秋二季较差。公牛淘汰年龄９３．４月龄,利用年限７０．１月龄。终生均产冻精８９０００余粒。制约繁殖性能的因素包括：年龄、季节、热应激、疾病等。     

阜平县土地资源利用状况分析

采用土地经济学研究方法,从土地利用结构、土地利用程度和土地利用效益3个方面,对阜平县2003年土地资源利用状况进行了对比分析.结果表明:近20a来,阜平县林业生产有较大发展,土地利用结构日趋合理,与其土地自然性状和林业县定位基本相符,但居民点及工矿用地增长较快,新开垦耕地多数利用方式不尽合理;土地利用程度有较大提高,荒山开发利用及林业建设成效明显,森林覆盖率26.26%,但森林资源区域分布不均匀,保持水土与调节生态和气候的作用依然有限;土地利用的总体效益有一定提高,但单位效益指标较低,需进一步改善生产条件、增加科技投入,提高土地资源利用效益.     

结合分析在市场研究中的应用

在市场研究中，结合分析用于估测产品或服务的属性和特征，对消费者的消费决策做出数量预测。本文对该方法的基本思想、分析过程以及应用前景进行论述。     

浅谈柴达木盆地白刺资源开发利用

白刺是一种高原沙生植物，其独特的生物学特性，耐干早、耐风沙、耐盐碱，是沙地盐碱荒漠地区造林的首选树种，同时决定了它的生态保护价值更大于经济价值。文章阐述了在保护和扩大柴达木盆地白刺资源的前提下，因地制宜，适时适量，合理开发利用。     

Combining holding-level economic goals with spatial landscape-level goals in the planning of multiple ownership forestry

In Finland, management of biological diversity at the landscape level is complicated by the relatively small size of the holdings. To alleviate this problem, this study presents a hierarchical planning model that aims at combining spatial landscape-level ecological goals with holding-level owner-specific goals. The influence of ecological objectives extends across holding borders, but their impact is greatest in areas where they are least in conflict with the owners goals. This feature, which results in minimum losses to individual landowners, can be called ecological efficiency. In the case study, the ecological objective was to cluster the breeding and foraging areas of flying squirrel (Pteromys volans). Other sets of objectives were related to individual holdings according to the various preferences of the forest owners. The forest plan produced by the presented planning model was compared with two other forest plans: 1) a combination of independent forest holding level plans, which were assumed to represent the outcome of the current planning tradition, and 2) an area-level plan, where the holding borders and holding-specific objectives were not taken into account. The same objective variables and objective weights were used in all plans. All the plans were produced for six planning areas (ranging from 404.6 to 984.9 ha) and 110 forest holdings (ranging from 0.6 to 449.8 ha) within these areas. The case-study results were promising: with the model presented here, the spatial structure of flying squirrel breeding and foraging areas could be improved with only minor losses in holding-level objectives. The spatial structure of the landscape after the 60-year planning period was very close to the area-level plan. This outcome was made possible by synchronizing the treatment proposals across forest-holding borders. The outcome of the model seems promising also from the practical standpoint: because the variation in the objectives of forest owners is efficiently taken into account in optimization, only rarely do the solutions suggest that the holding-level targets be compromised.This revised version was published online in May 2005 with corrections to the Cover Date.     

青南高寒地区特有树种红杉的保护和利用

红杉是我国西南高山特有树种,也是我省青南高寒地区分布面积较小、海拔较高的一个特有树种,红杉具有与其它树种不同的独特的生境条件和生物学特性,应在加强保护的基础上积极开展育苗、造林的试验研究,逐步扩大造林地域,为高寒冷湿地带的生态树种恢复提供科学依据。