调整结构 促进海水养殖业的发展

作者通过对山东省海水养殖业发展的剖析，认为今后山东省在现有的基础上成为渔业强省，海水养殖结构的调整仍是重要的手段和措施。其重点应从养殖品种、养殖海区及科技成果转换等方面着手。     

城市绿地树种规划在城市旅游形象塑造中的作用

城市旅游的兴起带动了城市旅游形象方面的研究,城市植物景观是城市旅游形象的重要载体,独具特色的植物景观对于塑造城市旅游形象与提升城市知名度具有举足轻重的作用。实施基于旅游功能的树种规划是营造和凸显城市旅游形象的有效途径,依据旅游"城市化"与城市休闲对树种规划的更高标准要求,提出具体的措施与建议,为传统基于生态功能的城市树种规划提供了有益的补充。     

鱼类外来物种入侵的法律管制分析

近年来,外来物种人侵给我国带来了巨大的经济损失,引起了国内学界及相关部门的重视。鱼类外来物种入侵给我国的渔业经济同样造成了巨大的经济损失。目前,却缺乏相应的法律管制。本文从我国当前的鱼类外来物种入侵现状着手,分析我国当前的外来物种人侵法律管制体系及存在的立法理念落后、法律规定缺位、管理机构混乱等问题;在此基础上,对鱼类外来物种入侵的法律管制提出了一些建议,希望能对加强鱼类外来物种入侵管理做出贡献,以促进渔业经济的健康发展。     

世界软体动物主要物种组产量变动趋势研究

过去60余年来,世界软体动物主要物种组产量呈现出总体稳定增长、个别年份有所波动的趋势。1990年以前10年期产量增幅均超过35％,20世纪90年代增长最快,2000—2008年间增幅变小。20世纪70年代初9养殖产量超过捕捞产量,2008年在主要物种组产量中所占份额高达86％。2008年,各物种组按产量高低排序为蛤类、牡蛎、扇贝、贻贝、鲍鱼和螺类,各大洲按产量高低排序为亚洲、美洲和欧洲,前10大生产国为中国、日本、美国、韩国、泰国、智利、法国、西班牙、意大利、加拿大。     

Deriving efficient frontiers for effort allocation in the management of invasive species*

Invasive species cause significant losses through their effect on agriculture, human health and the environment. Their importance has increased with time owing to globalisation, as the spread of invasive species is facilitated by the increased movement of people, cargo and genetic material around the world. There is a vast literature on the economics of invasive species and their management. Here, we contribute to this literature by applying a spatio‐temporal model to the allocation of surveillance resources. We focus on three questions regarding resource allocation to control a newly discovered invasion: the budget, which determines the amount of search effort available; the duration of the control program; and the allocation of surveillance and control in time and space. We also explore the complementary role of passive surveillance by members of the public. We derive efficient frontiers for effort allocation that represent the trade‐off between cost and probability of eradication after inefficient strategies have been eliminated. We use the results to illustrate how to evaluate whether introduction of passive surveillance is desirable based on cost and eradication probability. We conclude by discussing the implications of our findings in the design of control programs.     

大兴安岭樟子松林组成植物种的分布区类型

大兴安岭樟子松林组成植物521种,其中包括地衣植物35种,苔藓植物48种,维管束植物441种;分析了大兴安岭地区樟子松林组成植物种的多样性。     

生态恢复目标下的生态需水内涵探讨

随着生态环境破坏的日趋严重,生态需水问题日益引起生态学、水文学、农业气象学等领域科学研究人员的高度重视。该文分析了国内外生态需水问题的研究进展与存在的问题,审视和提出了生态需水的概念,认为生态需水是生态系统达到某种生态功能水平或者维持在某一动态平衡状态所需要的水量;对于不同的地区和不同的生态目标,生态需水量及其阈值不同。以此为基础,进一步探讨了干旱半干旱地区生态恢复及植被恢复与生态需水的关系。     

野外地物光谱测量技术及方法

野外地物光谱测量在航天航空传感器定标、遥感数据解译、遥感应用潜力研究以及地质填图等方面得到广泛应用。野外采集准确的地物波谱需要熟知各种不同的光照条件、大气特性和稳定性(云、风)、仪器视场角、观测和光线照射的结合角度、仪器扫描速度以及目标特征的时空变化等,这些因素对目标波谱具有很大的影响。进行野外光谱测量的第一步是整个试验的总体设计,在设计中必须结合研究目标和研究对象的具体特性综合考虑数据采集的时间、野外测量的空间尺度、光线照射和观测的几何角度以及记录的野外描述数据等问题。此文详细讨论这些因素对地物光谱测量的影响。     

Species preservation versus development: An experimental investigation under uncertainty

The safe minimum standard (SMS) is a decision rule to preserve renewable resources, unless the social costs of doing so are intolerable. While unpersuasive to many, support for the SMS has been advocated by some economists for settings involving irreversibility and a high degree of uncertainty. The objective of this paper is to explore decision-making involving species preservation versus development within an experimental laboratory setting, and involving uncertainty. The experimental design implements a number of prior game-theoretic investigations of the SMS (Bishop, 1978; Ready and Bishop, 1991; Palmini, 1999), involving insurance, and lottery or combined games against nature. The choices are between species preservation, which possibly provides a cure for a disease, or developing habitat, leading to irreversible depletion. Econometric results from a random parameters logit model, using responses from 117 participants (across both U.S. and Mexican university student samples) and 9 treatment choices, indicate that support for the SMS varies across the type of game, the imposed maximum regret condition concerning the relative magnitude of the costs of disease and net benefits of development, a constructed measure of respondents' risk aversion, and other factors. There is also strong evidence of unobservable heterogeneous preferences for preservation within our sample.     

Analysing the profitability of the Spanish fleet after the anchovy moratorium using bootstrap techniques

Given the low biomass level of the anchovy, the European Commission agreed to establish a moratorium on this species in the Bay of Biscay in 2005. Although the effects of managing the fishing activity with TACs, fees, taxes and ITQs on the stocks and future net profits are well documented in the specialized literature, scarce attention has been paid to analyze the effects of moratoriums on fisheries and the profitability of the fleet. This paper studies if the anchovy moratorium had a significant impact on the economic profitability of the fleet that fishes anchovy and other pelagic species in the North Atlantic waters. For this purpose, we compare the financial situations of the fleet before and after the moratorium from a statistical point of view using bootstrap, which is a flexible non-parametric and computationally intensive methodology. The results reveal the existence of a structural change in the financial performance of the fleet after the implementation of the moratorium.