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1.
自然保护区管理有效性评价指标分析   总被引:10,自引:0,他引:10  
根据154个国家级自然保护区的问卷调查结果,运用主成分分析法对26项管理评价指标进行分析,确定了影响保护区管理有效性的6个主要指标类体系。其结果表明:对管理有效性产生较大影响的主成分包括:物资保障、监控管理、经济开发收益、管理权归属、行政执法和交流合作。6个主成分对于管理有效性的贡献率比较分散,累计贡献率为68.671%;其中物资保障主成分贡献率最大,达26.011%。  相似文献   

2.
海平面上升对珠江口水位影响的分析   总被引:2,自引:0,他引:2  
孔兰  陈晓宏  张强  彭涛 《生态环境》2010,19(2):390-393
珠江三角洲水位变化存在着大量不确定性、不精确性,这些特性既具有模糊特征,也具有灰色特征。在分析珠江三角洲灯笼山站年平均水位的变化特征和闸坡站海平面变化趋势的基础上,利用灰关联法分析代表站灯笼山站年平均水位与流量、海平面、潮差等8个因素的关系,年平均水位与影响因素之间的灰关联度均大于0.7,说明各因子对年平均水位均产生显著影响,其中海平面变化与年平均水位的灰关联度为0.736,说明海平面变化是年平均水位的重要影响因素。选取灰关联度较大的(马+三)流量、闸坡站海平面、灯笼山站的年最高水位、年最低水位、年平均低潮、年平均潮差这6个指标进行主成分分析。结果表明:第一主成分为径流潮汐作用,第二主成分的代表因素为海平面上升,第三主成分的代表因素为年最高水位;其中海平面上升为代表的第二主成分对年平均水位的贡献率为20.1%。因此,海平面上升对灯笼山站年平均水位的影响虽然弱于径流潮汐作用,但其影响也是显著的。  相似文献   

3.
以山西介休金山坡煤矿采煤塌陷土壤为对象,通过接种幼套球囊霉(Glomus etunicatum,G.e)、根内球囊霉(G.intraradice,G.i)和摩西球囊霉(G.mosseae,G.m)3种丛枝菌根(Arbuscular mycorrhiza,AM)真菌,研究不同菌种对采煤塌陷区土壤生物学特性及玉米生产性能的影响.利用主成分-数值聚类方法对土壤和玉米的9个指标(脲酶、蔗糖酶、碱性磷酸酶、AM真菌丛枝丰度、总球囊霉素和易提取球囊霉素相关土壤蛋白以及玉米株高、茎粗和地上部干重)进行综合评价,筛选适合该矿区土壤复垦的最优菌种.结果表明,通过主成分分析方法对9个指标进行降维,共提取2个主成分,累计贡献率达81.04%.其中第1主成分以AM真菌丛枝丰度、球囊霉素相关土壤蛋白、脲酶、蔗糖酶及玉米株高、茎粗、地上部干重贡献最大,达到66.68%.第2主成分以磷酸酶活性贡献最大,达到14.36%.以两个主成分得分为新指标进行聚类得到接种不同AM真菌对塌陷矿区土壤培肥效果次序为G.eG.i、G.mCK.因此接种G.e是改善该采煤塌陷区土壤质量和提高玉米生产性能的最优菌种.  相似文献   

4.
基于主成分分析的中国南方干旱脆弱性评价   总被引:2,自引:0,他引:2  
王莺  ;王静  ;姚玉璧  ;王劲松 《生态环境》2014,(12):1897-1904
干旱脆弱性是干旱灾害形成的根本原因。遵循全面性、系统性和可操作性原则,选取水资源脆弱性、经济脆弱性、社会脆弱性、农业脆弱性和防旱抗旱能力脆弱性5个准则层,共32个指标,建立了中国南方农业干旱脆弱性评价指标体系,运用主成分分析的理论方法确定评价指标权重,建立中国南方地区的干旱脆弱性评价模型,得到不同省市的干旱脆弱性指数、分级阈值和区划,以期为南方地区防旱减灾工作提供基础数据和理论支持。得出以下结论,(1)通过主成分分析法得到四个主成分,第一主成分方差贡献率为54.90%,主要反映农业脆弱性和社会脆弱性;第二主成分方差贡献率为23.64%,主要反映水资源脆弱性和经济脆弱性;第三主成分和第四主成分所占比重较小,主要反映防旱抗旱能力脆弱性。(2)以4个主成分的方差贡献率为系数建立南方干旱脆弱性评价模型,得到中国南方干旱脆弱性综合评价得分及其排名,其中水资源脆弱性由高到低依次为云南、广西、贵州、四川、重庆和广东;经济脆弱性由高到低依次为广西、云南、贵州、四川、重庆和广东;社会脆弱性由高到低依次为贵州、云南、广西、重庆、四川和广东;农业脆弱性从高到低依次为贵州、云南、广西、重庆、四川和广东;防旱抗旱能力脆弱性由高到低分别为云南、贵州、四川、广西、重庆和广东;干旱脆弱性综合评价由高到低依次为云南、贵州、广西、四川、重庆和广东。(3)对干旱脆弱性指数进行正态分布性检验,发现该指数基本服从正态分布。根据正态分布原理,得到干旱脆弱性分级阈值,将干旱脆弱性指数小于0.3842定义为低风险,大于1.0758定义为高风险,介于两者之间的定义为中等风险,获得干旱脆弱性分级区划图。广东省位于干旱的低脆弱区,四川和?  相似文献   

5.
典型铜尾矿库周边土壤重金属复合污染特征   总被引:2,自引:0,他引:2  
应用了Hakanson潜在生态风险指数法、相关分析法、主成分分析法对德兴铜矿尾砂库周边土壤Cu、Zn、Ni、Pb、Cr和Cd复合污染特征进行研究,定量确定了铜尾矿库潜在生态风险程度、主要污染因子和潜在生态风险因子。结果表明:铜矿尾矿库周边土壤受到不同程度的重金属污染,该地区平均潜在生态风险污染指数超过600,具有极高的潜在生态风险;各重金属潜在生态风险参数由高至低顺序为Cd、Cu、Pb、Ni、Cr、Zn,其中Cd为主要潜在生态风险因子。进一步通过主成分分析法研究了重金属的污染特性,发现前3个主成分贡献率分别为:65.033%、18.825%、6.243%,第一主成分反映了Zn、Ni、Cr的信息,第二主成分反映了Cu和Cd的信息,第三主成分反映Pb的信息。  相似文献   

6.
为探明湘西花垣主要地表河流水重金属污染的程度,评估河流地表水的健康风险,于2016年8月、12月分别采取花垣县主要河流花垣河与兄弟河11个点位地表水水样,对水样中重金属铅(Pb)、锌(Zn)、铬(Cr)、铜(Cu)、铁(Fe)、镍(Ni)进行监测,并采用美国环境保护局(USEPA)推荐的健康风险评价模型,对花垣县主要地表河流水中的重金属进行健康风险评价.结果显示,研究区地表河流水中Pb、Zn、Cr、Cu、Fe与Ni的含量分别为2.57×10~(-3)、4.66×10-4、1.65×10~(-3)、6.27×10~(-4)、0.19、8.50×10~(-4) mg/L.地表河流水中重金属产生的健康风险较高,化学致癌物(Cr)的健康风险值高于化学非致癌物质(Pb、Zn、Cu、Ni)5-6个数量级,化学非致癌物质产生的健康风险均值大小为PbCuZnNi.地表河流水相关性及主成分分析表明,花垣县主要地表河流水中6种重金属元素由3个主成分组成,第一主成分Fe与Ni的贡献率为33.28%,主要来源于内源;第二主成分Cu与Cr的贡献率为26.98%,主要来源于重金属采选与冶炼企业产生的工业外排废水或雨水淋溶矿物废渣;第三主成分Zn的贡献率为17.10%,来源于地球化学行为.本研究表明湘西花垣县主要地表河流水由重金属引起的健康风险值较高,优先控制顺序为CrPbCuZnNi.  相似文献   

7.
选取山东小清河流域为研究区,在2012—2013年汛期和非汛期的水质监测基础上,应用主成分分析(PCA)和聚类分析(CA)等多元统计方法识别流域不同形态氮磷浓度的时空分布特征,结合空间分析和相关分析方法辨析集水区不同土地利用方式对氮磷输出的影响。结果表明:流域氮污染严重,其中总氮超标率达100%。氨氮、磷酸盐浓度汛期显著高于非汛期,硝态氮浓度则非汛期显著高于汛期(P0.05)。以总磷、总溶解态磷为主要指标的主成分Z1对水质变化的贡献率接近50%,以总氮、氨氮和硝态氮为主要指标的主成分Z2对水质变化的贡献率接近20%。总氮、总磷、氨氮、磷酸盐和总溶解态磷浓度与集水区城市和工业建设用地的面积比例呈显著正相关(P0.05);硝态氮浓度与耕地面积比例呈显著正相关,与草地、林地面积比例呈显著负相关(P0.05)。空间上按氮磷分布特征不同子流域被划分为3类:第1类和第2类主要集中在干流及北部平原区,沿途接纳点源排放,氮磷浓度总体较高且空间差异较大;第3类流域主要位于南部山区,建设用地比例较小,污染程度相对较低。  相似文献   

8.
基于多元统计的引黄水库沉沙条渠泥沙与水质的变异分析   总被引:1,自引:0,他引:1  
以济南市引黄供水鹊山水库沉沙条渠为研究对象,测定了9个断面(Y1—Y9)表层水体中的含沙量、总有机碳、总磷、总氮、叶绿素a等19个水质指标.运用主成分分析法和聚类分析法分别探讨水体的主要污染因子及监测断面的沿程归类,并通过室内模拟实验分析了泥沙对水体中N、P浓度的影响.结果表明,沉沙条渠中的水质总体特征以Ⅱ类水和Ⅲ类水为主,其中,超标水质指标为TN,达到劣Ⅴ类水标准,P为藻类生长的限制因子.19个水质指标可由6个主成分来反映,其贡献率分别为:F1(TN、NH3-N、NO3--N、NO2--N、总碱度、Br-、硫酸盐)34.41%,F2(含沙量、浊度、色度、电导率)22.78%,F3(pH和UV254)13.95%,F4(TP)6.280%,F5(CODCr)4.990%和F6(Chl-a)4.830%;9个监测断面归为4类,相应地整个沉沙条渠可划分为4个功能区:入渠布水区(Y1、Y2、Y3)、快速沉降区(Y4、Y5)、缓慢沉降区(Y6、Y7、Y8)和出水稳定区(Y9).此外,水质与泥沙关系的室内模拟实验表明,条渠来水的P浓度随着泥沙颗粒的沉降而降低,TP在0—15 h内快速下降,而后缓慢下降,30 h内基本达到平衡;而泥沙颗粒对水中N浓度基本没有影响.  相似文献   

9.
不同甘蔗基因型光合特性的数值分类   总被引:4,自引:0,他引:4  
对30个甘蔗基因型光合性状进行数值分类、主成分、聚类和判别分析研究认为,甘蔗基因型间光合性状存在较大差异;利用主成分分析选出3个主成分,方差累计贡献率达到98.5%,蒸腾速率、气孔导度为第一主成分的主导因子,而净光合速率和气孔导度分别为二、三主成分的主导因子;经系统聚类将30个基因型分为三大类,在聚类分析基础上用判别分析选出对甘蔗光合性状数值分类有显著影响的4个光合参数,建立3个判别能力较高的判别模型.表5图1参22  相似文献   

10.
选取南方14个典型农场,包括7个有机农场和7个相邻的常规农场,对其土壤物理指标(容重)、化学指标(pH值、有机质含量、全氮含量、全磷含量、速效磷含量、速效钾含量)和生物指标(微生物量碳含量,微生物群落多样性指数及优势度指数,线虫数量,线虫群落多样性指数及优势度指数)共13个指标进行统计分析。采用主成分分析法,筛选全氮含量、pH值、容重、微生物量碳含量、线虫数量和线虫群落优势度指数6个指标作为评价体系的最小数据集(minimum data set,MDS)。有机种植方式基于MDS的土壤质量指数(Is,q,6)为0.39~0.72,常规种植方式的Is,q,6为0.18~0.54,除1个样点外,有机种植方式的Is,q,6均高于常规种植方式。基于MDS的6个指标对土壤质量的贡献率为12.4%~21.8%,其中,线虫群落优势度贡献率最高。基于13个指标的土壤质量指数(Is,q,13)与Is,q,6呈显著正相关(r=0.89,P0.05),表明基于MDS的土壤质量评价是一种有效可行的评价方法。  相似文献   

11.
This paper is a contribution to the emergy evaluation of systems involving recycling or reuse of waste. If waste exergy (its residual usefulness) is not negligible, wastes could serve as input to another process or be recycled. In cases of continuous waste recycle or reuse, what then is the role of emergy? Emergy is carried by matter and its value is shown to be the product of specific energy with mass flow rate and its transformity. This transformity (τ) given as the ratio of the total emergy input and the useful available energy in the product (exergy) is commonly calculated over a specific period of time (usually yearly) which makes transformity a time dependent factor. Assuming a process in which a part of the non-renewable input is an output (waste) from a previous system, for the waste to be reused, an emergy investment is needed. The transformity of the reused or recycled material should be calculated based on the pathway of the reused material at a certain time (T) which results in a specific transformity value (τ). In case of a second recycle of the same material that had undergone the previous recycle, the material pathway has a new time (T + T1) which results in a transformity value (τ1). Recycling flows as in the case of feedback is a dynamic process and as such the process introduces its own time period depending on its pathway which has to be considered in emergy evaluations. Through the inspiration of previous emergy studies, authors have tried to develop formulae which could be used in such cases of continuous recycling of material in this paper. The developed approach is then applied to a case study to give the reader a better understanding of the concept. As a result, a ‘factor’ is introduced which could be included on emergy evaluation tables to account for subsequent transformity changes in multiple recycling. This factor can be used to solve the difficulties in evaluating aggregated systems, serve as a correction factor to up-level such models keeping the correct evaluation and also solve problems of memory loss in emergy evaluation. The discussion deals with the questions; is it a pure mathematical paradox in the rules of emergy? Is it consistent with previous work? What were the previous solutions to avoid the cumulative problem in a reuse? What are the consequences?  相似文献   

12.
Conserving coral reefs is critical for maintaining marine biodiversity, protecting coastlines, and supporting livelihoods in many coastal communities. Climate change threatens coral reefs globally, but researchers have identified a portfolio of coral reefs (bioclimatic units [BCUs]) that are relatively less exposed to climate impacts and strongly connected to other coral reef systems. These reefs provide a proactive opportunity to secure a long-term future for coral reefs under climate change. To help guide local management efforts, we quantified marine cumulative human impact (CHI) from climate, marine, and land pressures (2013 and from 2008 to 2013) in BCUs and across countries tasked with BCU management. Additionally, we created a management index based on common management measures and policies for each pressure source (climate, marine, and land) to identify a country's intent and commitment to effectively manage these pressures. Twenty-two countries (79%) had increases in CHI from 2008 to 2013. Climate change pressures had the highest proportional contribution to CHI across all reefs and in all but one country (Singapore), but 18 BCUs (35%) and nine countries containing BCUs (32%) had relatively high land and marine impacts. There was a significant positive relationship between climate impact and the climate management index across countries (R2 = 0.43, p = 0.02), potentially signifying that countries with greater climate impacts are more committed to managing them. However, this trend was driven by climate management intent in Fiji and Bangladesh. Our results can be used to guide future fine-scale analyses, national policies, and local management decisions, and our management indices reveal areas where management components can be improved. Cost-effectively managing local pressures (e.g., fishing and nutrients) in BCUs is essential for building a climate-ready future that benefits coral reefs and people.  相似文献   

13.
Every action in a conservation plan has a different level of effect and consequently contributes differentially to conservation. We examined how several community-based, marine, management actions differed in their contribution to national-level conservation goals in Fiji. We held a workshop with experts on local fauna and flora and local marine management actions to translate conservation goals developed by the national government into ecosystem-specific quantitative objectives and to estimate the relative effectiveness of Fiji's community-based management actions in achieving these objectives. The national conservation objectives were to effectively manage 30% of the nation's fringing reefs, nonfringing reefs, mangroves, and intertidal ecosystems (30% objective) and 10% of other benthic ecosystems (10% objective). The experts evaluated the contribution of the various management actions toward national objectives. Scores ranged from 0 (ineffective) to 1 (maximum effectiveness) and included the following management actions: permanent closures (i.e., all extractive use of resources prohibited indefinitely) (score of 1); conditional closures harvested once per year or less as dictated by a management plan (0.50-0.95); conditional closures harvested without predetermined frequency or duration (0.10-0.85); other management actions, such as regulations on gear and species harvested (0.15-0.50). Through 3 gap analyses, we assessed whether the conservation objectives in Fiji had been achieved. Each analysis was based on a different assumption: (1) all parts of locally managed marine areas (including closures and other management) conserve species and ecosystems effectively; (2) closures conserve species and ecosystems, whereas areas outside closures, open to varying levels of resource extraction, do not; and (3) actions that allow different levels of resource extraction vary in their ability to conserve species and ecosystems. Under assumption 1, Fiji's national conservation objectives were exceeded in all marine ecosystems; under assumption 2, none of Fiji's conservation objectives were met; and under assumption 3, on the basis of the scores assigned by experts, Fiji achieved the 10% but not the 30% objectives for ecosystems. Understanding the relative contribution of management actions to achieving conservation objectives is critical in the assessment of conservation achievements at the national level, where multiple management actions will be needed to achieve national conservation objectives.  相似文献   

14.
Antarctic specially protected areas (ASPAs) are a key regulatory mechanism for protecting Antarctic environmental values. Previous evaluations of the effectiveness of the ASPA system focused on its representativeness and design characteristics, presenting a compelling rationale for its systematic revision. Upgrading the system could increase the representation of values within ASPAs, but representation alone does not guarantee the avoided loss or improvement of those values. Identifying factors that influence the effectiveness of ASPAs would inform the design and management of an ASPA system with the greatest capacity to deliver its intended conservation outcomes. To facilitate evaluations of ASPA effectiveness, we devised a research and policy agenda that includes articulating a theory of change for what outcomes ASPAs generate and how; building evaluation principles into ASPA design and designation processes; employing complementary approaches to evaluate multiple dimensions of effectiveness; and extending evaluation findings to identify and exploit drivers of positive conservation impact. Implementing these approaches will enhance the efficacy of ASPAs as a management tool, potentially leading to improved outcomes for Antarctic natural values in an era of rapid global change. Evaluación del impacto de conservación de las áreas protegidas de la Antártida  相似文献   

15.
Abstract: Valid modeling of habitats and populations of Greater Sage-Grouse ( Centrocercus urophasianus) is a critical management need because of increasing concern about population viability. Consequently, we evaluated the performance of two models designed to assess landscape conditions for Greater Sage-Grouse across 13.6 million ha of sagebrush steppe in the interior Columbia Basin and adjacent portions of the Great Basin of the western United States (referred to as the basin). The first model, the environmental index model, predicted conditions at the scale of the subwatershed (mean size of approximately 7800 ha) based on inputs of habitat density, habitat quality, and effects of human disturbance. Predictions ranged on a continuous scale from 0 for lowest environmental index to 2 for optimal environmental index. The second model, the population outcome model, predicted the composite, range-wide conditions for sage grouse based on the contribution of environmental index values from all subwatersheds and measures of range extent and connectivity. Population outcomes were expressed as five classes (A through E) that represented a gradient from continuous, well-distributed populations (outcome A) to sparse, highly isolated populations with a high likelihood of extirpation (outcome E). To evaluate performance, we predicted environmental index values and population outcome classes in areas currently occupied by sage grouse versus areas where extirpation has occurred. Our a priori expectations were that models should predict substantially worse environmental conditions ( lower environmental index) and a substantially higher probability of extirpation ( lower population outcome class) in extirpated areas. Results for both models met these expectations. For example, a population outcome of class E was predicted for extirpated areas, as opposed to class C for occupied areas. These results suggest that our models provided reliable landscape predictions for the conditions tested. This finding is important for conservation planning in the basin, where the models were used to evaluate management of federal lands for sage grouse.  相似文献   

16.
Previous assessments of the effectiveness of protected areas (PAs) focused primarily on changes in human pressure over time and did not consider the different human-pressure baselines of PAs, thereby potentially over- or underestimating PA effectiveness. We developed a framework that considers both human-pressure baseline and change in human pressure over time and assessed the effectiveness of 338 PAs in China from 2010 to 2020. The initial state of human pressure on PAs was taken as the baseline, and changes in human pressure index (HPI) were further analyzed under different baselines. We used the random forest models to identify the management measures that most improved effectiveness in resisting human pressure for the PAs with different baselines. Finally, the relationships between the changes in the HPI and the changes in natural ecosystems in PAs were analyzed with different baselines. Of PAs with low HPI baselines, medium HPI baselines, and high HPI baselines, 76.92% (n=150), 11.11% (n=12), and 22.86% (n=8) , respectively, showed positive effects in resisting human pressure. Overall, ignoring human-pressure baselines somewhat underestimated the positive effects of PAs, especially for those with low initial human pressure. For PAs with different initial human pressures, different management measures should be taken to improve effectiveness and reduce threats to natural ecosystems. We believe our framework is useful for assessing the effectiveness of PAs globally, and we recommend it be included in the Convention on Biological Diversity Post-2020 Strategy.  相似文献   

17.
Systematic reviews comprehensively summarize evidence about the effectiveness of conservation interventions. We investigated the contribution to management decisions made by this growing body of literature. We identified 43 systematic reviews of conservation evidence, 23 of which drew some concrete conclusions relevant to management. Most reviews addressed conservation interventions relevant to policy decisions; only 35% considered practical on‐the‐ground management interventions. The majority of reviews covered only a small fraction of the geographic and taxonomic breadth they aimed to address (median = 13% of relevant countries and 16% of relevant taxa). The likelihood that reviews contained at least some implications for management tended to increase as geographic coverage increased and to decline as taxonomic breadth increased. These results suggest the breadth of a systematic review requires careful consideration. Reviews identified a mean of 312 relevant primary studies but excluded 88% of these because of deficiencies in design or a failure to meet other inclusion criteria. Reviews summarized on average 284 data sets and 112 years of research activity, yet the likelihood that their results had at least some implications for management did not increase as the amount of primary research summarized increased. In some cases, conclusions were elusive despite the inclusion of hundreds of data sets and years of cumulative research activity. Systematic reviews are an important part of the conservation decision making tool kit, although we believe the benefits of systematic reviews could be significantly enhanced by increasing the number of reviews focused on questions of direct relevance to on‐the‐ground managers; defining a more focused geographic and taxonomic breadth that better reflects available data; including a broader range of evidence types; and appraising the cost‐effectiveness of interventions. Contribuciones de las Revisiones Sistemáticas a las Decisiones de Manejo  相似文献   

18.
19.
• The effectiveness of four different ventilation systems was compared in depth. • Airflow and bacteria-carrying particles concentration were quantitatively analyzed. • Vertical laminar airflow with high airflow rate could not achieve desired effect. • Temperature-controlled airflow ventilation could guarantee air cleanliness. Biological particles in the operating room (OR) air environment can cause surgical site infections (SSIs). Various ventilation systems have been employed in ORs to ensure an ultraclean environment. However, the effect of different ventilation systems on the control of bacteria-carrying particles (BCPs) released from the surgical staff during surgery is unclear. In this study, the performance of four different ventilation systems (vertical laminar airflow ventilation (VLAF), horizontal laminar airflow ventilation (HLAF), differential vertical airflow ventilation (DVAF), and temperature-controlled airflow ventilation (TAF)) used in an OR was evaluated and compared based on the spatial BCP concentration. The airflow field in the OR was solved by the Renormalization Group (RNG) k-e turbulence model, and the BCP phase was calculated by Lagrangian particle tracking (LPT) and the discrete random walk (DRW) model. It was found that the TAF system was the most effective ventilation system among the four ventilation systems for ensuring air cleanliness in the operating area. This study also indicated that air cleanliness in the operating area depended not only on the airflow rate of the ventilation system but also on the airflow distribution, which was greatly affected by obstacles such as surgical lamps and surgical staff.  相似文献   

20.
Abstract: The mandate to increase endangered salmon populations in the Columbia River Basin of North America has created a complex, controversial resource‐management issue. We constructed an integrated assessment model as a tool for analyzing biological‐economic trade‐offs in recovery of Snake River spring‐ and summer‐run chinook salmon (Oncorhynchus tshawytscha). We merged 3 frameworks: a salmon‐passage model to predict migration and survival of smolts; an age‐structured matrix model to predict long‐term population growth rates of salmon stocks; and a cost‐effectiveness analysis to determine a set of least‐cost management alternatives for achieving particular population growth rates. We assessed 6 individual salmon‐management measures and 76 management alternatives composed of one or more measures. To reflect uncertainty, results were derived for different assumptions of effectiveness of smolt transport around dams. Removal of an estuarine predator, the Caspian Tern (Sterna caspia), was cost‐effective and generally increased long‐term population growth rates regardless of transport effectiveness. Elimination of adult salmon harvest had a similar effect over a range of its cost estimates. The specific management alternatives in the cost‐effective set depended on assumptions about transport effectiveness. On the basis of recent estimates of smolt transport effectiveness, alternatives that discontinued transportation or breached dams were prevalent in the cost‐effective set, whereas alternatives that maximized transportation dominated if transport effectiveness was relatively high. More generally, the analysis eliminated 80–90% of management alternatives from the cost‐effective set. Application of our results to salmon management is limited by data availability and model assumptions, but these limitations can help guide research that addresses critical uncertainties and information. Our results thus demonstrate that linking biology and economics through integrated models can provide valuable tools for science‐based policy and management.  相似文献   

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