Extent and ecological consequences of hunting in Central African rainforests in the twenty-first century

Humans have hunted wildlife in Central Africa for millennia. Today, however, many species are being rapidly extirpated and sanctuaries for wildlife are dwindling. Almost all Central Africa''s forests are now accessible to hunters. Drastic declines of large mammals have been caused in the past 20 years by the commercial trade for meat or ivory. We review a growing body of empirical data which shows that trophic webs are significantly disrupted in the region, with knock-on effects for other ecological functions, including seed dispersal and forest regeneration. Plausible scenarios for land-use change indicate that increasing extraction pressure on Central African forests is likely to usher in new worker populations and to intensify the hunting impacts and trophic cascade disruption already in progress, unless serious efforts are made for hunting regulation. The profound ecological changes initiated by hunting will not mitigate and may even exacerbate the predicted effects of climate change for the region. We hypothesize that, in the near future, the trophic changes brought about by hunting will have a larger and more rapid impact on Central African rainforest structure and function than the direct impacts of climate change on the vegetation. Immediate hunting regulation is vital for the survival of the Central African rainforest ecosystem.     

城市近郊型乡镇农业生态经济系统生态潜力及产业空间布局——以延安市河庄坪镇为例

生态脆弱区抗干扰能力弱，明确其系统的生态潜力，在潜力的基础上开发利用资源对区域的可持续发展具有重要的意义。研究基于生态系统服务价值视角，尝试测度农业生态经济系统生态潜力，同时以三产融合典型代表乡镇为研究对象，对其农业生态经济系统生态潜力和主导产业进行时空分析，最后对生态系统加以功能分区。结果显示：（1）气体调节、气候调节、水源涵养和土壤形成与保护是生态系统提供的主要服务功能。随退耕还林工程实施，林地面积的增加使生态系统服务价值量随之上升，在空间上呈现"中间低两翼高"的格局。（2）农业生态经济系统生态潜力受服务价值与资源开发过程影响，与生态系统服务价值在空间上相对一致，呈现出"两翼高中间低，北高南低"的分布格局，其中，退耕还林工程的推进直接导致林地的生态潜力增加，耕地的生态潜力减少。（3）研究区在退耕过程中形成以大棚种植为主的设施农业、以农林特色销售为主的商品型种植农业，以山地苹果为主的林果产业以及以酒店商贸为主的服务行业。并随城镇一体化的推进，主导产业呈现出由传统粗放型大田种植向集约型设施农业方向发展。在空间上形成了以镇区分布为主的第三产业、依托拐沟坡地的林果产业和沿川道展开的设施农业的产业布局。（4）基于生态系统服务价值，研究区农业生态经济系统功能区划分为城镇生态环境维护区（第Ⅰ类型区）、农业生态保护区（第Ⅱ类型区）、生态安全屏障区（第Ⅲ类区）3个区域。     

Palaeodistribution modelling does not support disjunct Pleistocene refugia in several Central American plant taxa

Aim We combine evidence from palaeoniche modelling studies of several tree species to estimate the extent of Central American forest during the Last Glacial Maximum (LGM). In particular, we ask whether the distributions of these species are likely to have changed since the LGM, and whether LGM distributions coincide with previously proposed Pleistocene refugia in this area. Location Central American wet and seasonally dry forests. Methods We developed ecological niche models using two simulations of Pleistocene climate and occurrence data for 15 Neotropical plant species. We focused on palaeodistribution models of three ‘focal’ tree species that occur in wet and seasonally dry Central American forests, where recent phylogeographic data suggest Pleistocene differentiation coincident with previously proposed refugia. We added predictions from six wet‐forest and six seasonally dry‐forest obligate plant species to gauge whether Pleistocene range shifts were specific to habitat type. Correlation analyses were performed between projected LGM and present distributions, LGM distributions and previously proposed refugia. We also asked whether modelled palaeodistributions were smaller than their current extents. Results According to our models, the ranges of the study species were not reduced during the LGM, and did not correlate with refugial models, regardless of habitat type. Relative range sizes between present and LGM distributions did not indicate significant range changes since the LGM. However, relative range sizes differed overall between the two palaeoclimate models. Main conclusions Many of the modelled palaeodistributions of study species were not restricted to refugia during the LGM, regardless of forest type. While constrained from higher elevations, most species found suitable habitat at coastal margins and on newly exposed land due to lowered sea levels during the LGM. These results offer no corroboration for Pleistocene climate change as a driver of genetic differentiation in the ‘focal’ species. We offer alternative explanations for genetic differentiation found in plant species in this area.     

基于地质灾害敏感性的生态安全格局关键区识别与修复——以济南市为例

区域生态安全格局构建对提升生态系统服务功能提供了重要路径，同时统筹各种生态要素进行生态保护与修复分区也是新时期做好生态修复的重要举措。以济南市为例，基于现状生态系统类型分布，聚焦生态本底和地质灾害敏感性的特征，基于形态学空间格局分析方法和自然保护区结合进行生态源地提取。采用夏季降水、植被覆盖度、坡度3个地质灾害敏感性因子修正基本生态阻力面。并采用最小成本路径方法（Least-Cost Path method，LCP）提取生态廊道，构建了市域的生态安全格局。采用电路理论进行生态关键区域（生态"夹点"和生态障碍点）的识别，进一步划分生态修复改善区，并对此提出针对性的生态保护修复策略和工程措施。研究表明：1）市域生态源地的个数为35个，面积为567.15 km²，主要类型为林地和草地。空间上主要分布南部山区。生态廊道818.42 km，平均廊道长度为12.99 km，廊道分布存在较为明显的空间分布差异性，整体呈现出"一屏、一带、三轴"的生态安全格局。2）识别的生态修复关键区包含生态"夹点"25处，历城区生态"夹点"分布最为密集。全市亟需修复的生态障碍点共34处，面积为6.90 km²，主要分布章丘区。生态改善区共识别2994.84 km²，近期亟需修复的面积为96.1 km²，主要分布在长清区、历城区、莱芜区。3）通过对比生态修复关键区和现状土地利用类型，因地适宜的制定了生态修复策略与工程措施布置指引方向。研究结果可为济南市国土空间生态修复规划提供一定的技术支撑，同时也可为其他地质灾害敏感性区域的生态修复规划提供指引。     

Policy measures to address bird interactions with power lines – a comparative case study of four countries

Bird mortality caused by electric power lines has been an issue in several countries for more than three decades now. Despite serious efforts by conservationists, government agencies and utility companies assisted by increasing biological and technological knowledge, only a minority of countries has made significant progress in mitigation. In the present article I argue that the policy aspects, which have not been so widely researched so far, have considerable effects on the efficiency of mitigation measures. The problem management methods of four countries—Hungary, Slovakia, South Africa and the USA—are discussed in detail to reveal success criteria. The role of contextual factors, stances and relations of different actors, plus actions and tools applied in the solution process, are demonstrated together with the resulting outcomes. To help strategic planning, I review favourable solution methods (volunteer agreements, legislative steps, mixed solutions, etc.) used in different country-specific contexts, and point out probable consequences of the strategy chosen.     

基于享乐价格-结构方程双模型的西宁城市湿地生态系统服务价值及影响因素研究

湿地为城市发展提供巨大的生态系统服务，但其被市场“认可”的经济价值难以准确评估。以青海省西宁市城市湿地为例，筛选房屋结构、可达性、环境、湿地等10个因子，采用享乐价格模型对110个湿地周边社区样点的因子数据(2020年)进行分析，定量分析城市湿地被市场“认可”的价值量。采用断裂点理论和加权Voronoi图模型方法等，分析了湿地生态系统服务价值的空间影响范围；构建了湿地生态系统服务价值影响因素的结构方程模型，探究了影响湿地生态系统服务价值的主要因素。结果表明：(1)2020年湟水城市湿地的总价值达到3.367亿元，约有54.3%的生态系统服务通过房产被市场转化；(2)湟水湿地单位面积的生态系统服务价值为151.916元/m~2,生态系统服务价值由大到小排列：火烧沟(1.632亿元)>海湖湿地(0.710亿元)>宁海湿地(0.629亿元)>北川湿地(0.330亿元);(3)湿地生态系统服务价值占房产总价值的比例达到2.04%,位列10个因素中的第7位；线性函数模型结果显示，购买者对湿地的边际支付意愿是0.12元/m~2,即购买者愿意为房产与湿地之间的距离每缩小1m而多支付...     

碳储存变化背景下东营市海岸带生态系统保护修复

生态修复是指在不同人为干预程度下，协助已遭受退化、损伤或破坏的生态系统恢复的过程。我国海岸带地区资源丰富、位置优越，但过度的开发建设活动严重破坏了当地的生态环境，急需对受损的海岸带生态系统进行保护和修复。以东营市海岸带地区为例，运用InVEST模型对其2005、2010、2015和2018年4个时间段的碳储存功能进行评估并分析碳储存及"碳源碳汇"的动态变化，以间接反映出区域生态系统的稳定性和健康程度。结果表明，2005-2018年东营市海岸带碳储存功能持续减弱，13年间碳储存总量减少了1.341×10⁶ t，生态系统碳储存功能受到严重破坏，其中有8.68×10⁴ hm²生态系统碳储存功能评价等级为差和极差，空间上受损最为严重的区域主要分布在岸线附近的北部、东北部和东南部。按照东营市海岸带碳损失空间差异和生态系统演替规律，从3个方面提出相应的修复方案，包括加强恢复区保护力度、稳定碳储存能力，整顿辅助区粗放模式、塑造碳储存廊道和退还重建区滨海湿地、扭转碳损失趋势，以期通过改善和恢复研究区海岸带生态系统碳储存功能，实现对受损生态系统的有效保护和修复。