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1.
José Guerreiro Aldo Chircop David Dzidzornu Catarina Grilo Raquel Ribeiro Rudy van der Elst Ana Viras 《Marine Policy》2011
The increasing degradation of marine ecosystems has led to multiple calls for greater protection through the establishment of marine protected areas (MPAs). If created at the ecosystem or ecoregion level, MPAs will likely straddle maritime boundaries and therefore necessitate international cooperation. International environmental law and international law of the sea may facilitate cooperation between States in creating transboundary MPAs. The extent to which this body of law is actually or potentially useful for the establishment of transboundary MPAs is examined in the context of the East African Marine Ecoregion, focusing on Mozambique, South Africa, and Tanzania. A general survey and assessment of the applicable global, regional, and bilateral instruments in relation to the three States is conducted. Although some global instruments are relevant in the East African context, regional and bilateral instruments are more conducive to the establishment of transboundary MPAs. The article concludes that although a trilateral agreement between Mozambique, South Africa, and Tanzania would be an ideal vehicle for the establishment of a transboundary network of MPAs addressing both national and ecoregional conservation interests, a separate solution at each border will be the first step towards this goal. 相似文献
2.
Conservation planning and resulting ecological target identification require selection of both a planning area boundary and temporal baseline or reference condition. We examined the effects that these selections can have on resulting amount and location of identified conservation targets. A gap analysis for California was conducted using five different sets of ecoregion boundaries to identify and compare existing conservation shortfalls in major land cover type representation in protected areas using a threshold of 30 percent per ecoregion per type as the minimum required for future ecological viability. Another gap analysis was run for a single ecoregion using two temporal baselines (current and pre-1900) for the land cover followed by a comparison of identified conservation needs. We found that the boundaries of different ecoregional schemes affected both the total area needed to meet the per ecoregion land cover conservation goals and the spatial location of underprotected land cover types. Choice of temporal baseline also had a significant effect on the establishment of conservation targets for the highly human-impacted Central Valley ecoregion. To meet the given conservation threshold using a historic rather than contemporary baseline, a substantial amount of restoration is required. The results can help identify areas of both conservation needs consensus and those that vary widely based on the chosen planning boundary, as well as aid in the selection of appropriate restoration targets in degraded ecosystems. Because all landscapes are continuous in nature and planning area boundaries are discrete, similar results are likely to be found in analyses conducted in other regions. 相似文献
3.
滇池生态系统退化成因、格局特征与分区分步恢复策略 总被引：5，自引：3，他引：2
选取生态系统中重要的组成成份:浮游植物、底栖动物、水生植物的历史演变和现在分布状况数据,结合水质变化情况,揭示了滇池生态系统退化原因:在外因上,污染物持续输入以及围湖造田、直立堤岸和水量交换缓慢等外力干扰加剧系统组分失衡是直接原因;在内因上,由于滇池所处的地理位置、气候等原因,蓝藻生物量对营养盐增加的响应远高于其他湖泊(太湖、巢湖),草型向藻型湖泊的转换进程更快;与太湖和东湖的生态系统比较,高原湖泊滇池生态系统相对脆弱,如物种的同域分化、窄生态位,导致系统的稳定性差、自我修复能力弱.通过对滇池生态格局特征、湖岸带结构的分析,将滇池划分为5个生态区:草海重污染区、藻类聚集区、沉水植被残存区、近岸带受损区和水生植被受损区,并提出"五区三步,南北并进,重点突破,治理与修复相结合"的滇池生态系统分区分步治理的新策略和"南部优先恢复;北部控藻治污;西部自然保护;东部外围突破"的总体方案. 相似文献
4.
基于遥感反演参数与双约束空间聚类算法的湖泊营养物生态分区 总被引：1，自引：0，他引：1
中国湖泊营养物水平和富营养化效应存在显著区域分异特征,开展湖泊营养物生态分区研究,是实现湖泊分区控制的前提和基础。本文以云贵高原亚热带湿润区为案例区,通过遥感反演得到研究区域湖泊水体的叶绿素a(Chl-a)、总氮(TP)和总磷(TN)含量,从自然地理要素、生态系统和人类活动3 方面建立指标体系;根据研究区域 DEM数据划分小流域,将各指标因子投影到小流域;在小流域尺度上,采用数理统计方法定量分析各指标分别对 Chl-a/P 与Chl-a/N 的作用,计算两种湖泊营养物生态分区评价分值;采用双约束空间聚类算法对小流域尺度上两种湖泊营养物生态分区评价分值共同进行聚类,形成湖泊营养物生态分区结果。研究发现：①通过遥感反演模型可以将少数呈点状分布的监测数据推演到面上,这在一定程度上弥补了有限的野外监测数据量难以支撑湖泊营养物生态分区的不足;②通过构建各指标因子分别与湖泊水体中Chl-a/P、Chl-a/N 的定量关系,实现了湖泊营养物生态分区中湖泊水体微观指标与湖泊流域宏观指标的有机结合;③采用双约束空间聚类进行湖泊营养物生态分区,保证了分区结果在空间上的连续性和评价分值上的接近性;④根据自然地理条件、土地利用和人类活动强度的不同,将云贵高原亚热带湿润区分为4 个区：北云南高原湖区、滇南河谷山原湖区、桂西-滇东-黔南岩溶湖区、贵州高原东北部湖区。本文提出的基于双约束空间聚类的湖泊营养物生态分区方法也可以作为其它地区乃至国家尺度湖泊营养物生态分区的借鉴。 相似文献
5.
Water temperature is a key driver for riverine biota and strongly depends on shading by woody riparian vegetation in summer. While the general effects of shading on daily maximum water temperature Tmax are well understood, knowledge gaps on the role of the spatial configuration still exist. In this study, the effect of riparian buffer length, width, and canopy cover (percentage of buffer area covered by woody vegetation) on Tmax was investigated during summer baseflow using data measured in seven small lowland streams in western Germany (wetted width 0.8–3.7 m). The effect of buffer length on Tmax differed between downstream cooling and heating: Tmax approached cooler equilibrium conditions after a distance of 0.4 km (~45 min travel-time) downstream of a sharp increase in canopy cover. In contrast, Tmax continued to rise downstream of a sharp decrease in canopy cover along the whole 1.6 km stream length investigated. The effect of woody vegetation on Tmax depended on buffer width, with changes in canopy cover in a 10 m wide buffer being a better predictor for changes in Tmax compared to a 30 m buffer. The effect of woody vegetation on Tmax was linearly related to canopy cover but also depended on daily temperature range Trange, which itself was governed by cloudiness, upstream canopy cover, and season. The derived empirical relationship indicated that Tmax was reduced by −4.6°C and increased by +2.7°C downstream of a change from unshaded to fully shaded conditions and vice versa. This maximum effect was predicted for a 10 m wide buffer at sunny days in early summer, in streams with large diel fluctuations (large Trange). Therefore, even narrow woody riparian buffers may substantially reduce the increase in Tmax due to climate change, especially in small shallow headwater streams with low baseflow discharge and large daily temperature fluctuations. 相似文献
6.
辽宁北部典型流域水生态功能区水生态安全评价 总被引：1，自引：0，他引：1
基于流域水生态功能分区的水生态安全评价是指导流域水生态“分类、分区”综合管理的前提,本文在流域中小尺度上依据水生态空间格局分异的自然特征和社会属性,以辽河流域的清河和凡河支流为对象,在流域水生态功能三级分区的基础上,运用“压力-状态-响应模型”（PSR）,通过对流域社会经济压力指标、环境压力指标、城市发展指标、资源环境发展指标、投资指标、治理指标等因素分析,筛选出13个评价指标。利用生态安全综合指数法,将流域水生态安全划分为极不安全、不安全、基本安全、安全、非常安全五个级别。其中,清河流域Ⅳ-5-9、Ⅳ-5-10、Ⅳ-5-11、Ⅳ-5-12、Ⅳ-5-14区处于基本安全,Ⅳ-5-8、Ⅳ-5-13属于不安全;凡河流域4个水生态功能三级区中,Ⅳ-5-1、Ⅳ-5-2、Ⅳ-5-3区属于基本安全、Ⅳ-5-4区为较安全。基于水生态功能分区的水生态安全评价和级别划分可为辽河流域水生态保护与流域生态管理提供科学依据。 相似文献
7.
José Guerreiro Aldo Chircop Catarina Grilo Ana Viras Raquel Ribeiro Rudy van der Elst 《Marine Policy》2010
International conservation efforts and cooperation are increasingly necessary, particularly at an ecoregion level, for the achievement of international targets for protecting biodiversity and degradation of ecosystems. Whereas more than 11 percent of land is protected, less than 1 percent of marine space is similarly protected. Transboundary networks of marine protected areas and transboundary marine protected areas (TBMPAs) are an essential form of cooperation for meeting these international targets. This paper explores the diplomatic and political options for regional and sub-regional cooperation between Tanzania, Mozambique, and South Africa, for the establishment of transboundary conservation mechanisms in the Eastern African Marine Ecoregion (EAME). Five options for the establishment and management of these mechanisms are presented, together with actions to be taken to facilitate cooperation. The paper deal with a proposed strategy for the implementation of transboundary conservation mechanisms, focusing on TBMPAs, between the three countries at a biogeographical/sub-regional level, supported by lessons learnt in other transboundary marine conservation experiences. The paper concludes that although political will may exist among States sharing borders to establish TBMPAs, the complexity of dealing with sub-regional realities is a difficult obstacle to overcome in a single step. The situation at each border must be taken into account in order that different multi-scale and multivariate solutions, supported by a common baseline will ultimately converge in a common trilateral framework. Finally, a two-step approach seems to be in course with the declaration (October 2009) of a TBMPA linking Ponta do Ouro in Mozambique to iSimangaliso Wetland Park in South Africa, following one of the options formerly presented. 相似文献
8.
辽河流域水生态功能一级分区指标体系与技术方法 总被引：2，自引：0，他引：2
流域水生态功能分区是实现流域综合管理的重要基础,也是水环境管理由水质目标管理向流域水生态管理转变的重要依据。根据辽河流域大尺度水生态空间格局分异的自然属性,结合国内外相关生态环境分区的研究进展,通过对辽河流域水热比（P/T）、径流深（RD）、数字高程（DEM）、多年归一化植被指数（NDVI）和水文地质（RP）等自然因素、河流水环境因子及水生生物指标的典型相关分析（CCA）,筛选出DEM、RD、RP、NDVI指数作为水生态功能一级分区的主要因子,并依此建立了辽河流域水生态功能一级分区指标体系与分区技术方法。结果表明：辽河流域可分为4个水生态功能一级区,即西辽河上游内蒙古大兴安岭东南—冀北山地丘陵水生态区、西辽河中下游西辽河平原水生态区和辽河中下游平原水生态区及浑河—太子河上游山地丘陵水生态区。辽河流域多年历史数据与野外水生态调查数据分析表明,流域内鱼类聚类分析结果与水生态功能一级分区结果在空间分布上具有较好的吻合性。水生态功能分区结果为辽河流域水生态综合管理提供了科技支撑,同时也为中国水生态功能分区技术方法的制订提供了参考依据。 相似文献
9.
根据生态环境分类指标的科学性、完备性、简洁性和数据的可获取性,选取了影响拉萨地区生态环境的主要地形和气候因子高程、坡向、≥0℃积温、年平均温度、年平均降水量、潜在蒸散量和湿润度等7个有代表性的指标,利用GIS的空间内插方法将所有这些指标转成100 m×100 m的空间珊格数据,再根据每个指标特定的地理和环境意义进行指标的分带,对7个指标进行主成分分析后提取主要信息。通过选择4个典型样区作为训练区,对拉萨地区的生态环境进行了分类。结果表明,拉萨地区的主要生态环境类型包括河谷农业类型、山地草原类型、高山草甸类型及高山裸岩及冰雪类型。其中,高山草甸和山地草原生态环境类型占主导,分别为10 768.52 km2和10 646.6 km2,各占总面积的36.61%和36.20%,而河谷农业类型占总面积的10.75%。此外,拉萨地区分布有较大面积的高山裸岩及冰雪区生态环境类型,面积为总面积的14.16%。作为特殊类型的生态环境类型,拉萨地区境内的纳木错的湖泊面积是668.76 km2,占该湖面积的近一半和拉萨地区总面积的2.27%。 相似文献
10.
2001-2013年华北地区植被覆盖度与干旱条件的相关分析 总被引：8，自引：1，他引：7
基于MODIS-NDVI遥感数据以及地表气象数据,计算了2001-2013年华北地区的修正Palmer干旱指数（Palmer Drought Severity Index,PDSI）和植被覆盖度,总结出植被覆盖度以及PDSI的年际变化规律,从华北地区生态分区的角度分析了二者的相关关系。结果表明：① 华北平原的植被覆盖度呈南高北低、中部高四周低的分布特点,最低为内蒙古高原草原生态区的0.61,最高为淮阳丘陵地区的0.84;② 2001-2013年,华北平原整体植被覆盖度主要呈上升趋势,其中华北的北部、西部、南部山区及丘陵地带植被覆盖度主要呈上升趋势,而华北平原农业区以及京津唐城郊地带植被覆盖度呈下降趋势;③ 华北地区的东北部有变潮湿的趋势,南部则有变干旱的趋势,其他地区干旱条件变化不明显;④ 华北地区植被覆盖度与气候干旱程度的平均相关系数为0.20,73.37%的地区相关系数为正,正相关关系最为明显的地区为华北地区的西北部,而北京、天津、以及河北省与河南省一级、二级城市的城郊地区相关系数多为负值。⑤ 在华北大部分地区,夏季和秋季的气候干旱条件对植被覆盖度的影响最为明显。 相似文献