Importance of movement constraints in habitat selection studies

The aim of this study is to empirically illustrate the importance of taking movement constraints into account when testing for habitat selection with telemetry data. Global Positioning System relocations of two Scandinavian brown bears were used to compare the results of two different tests of habitat selection by the bears within their home range. Both relied on the comparison of observed dataset with datasets simulated under the hypothesis of random habitat use. The first analysis did not take movement constraints into account (simulations were carried out by randomly distributing a set of points in the home range) whereas the second analysis accounted for these constraints (simulations were carried out by building random trajectories in the home range). The results for the two analyses showed contrasted results. Therefore, not accounting for movement constraints in analyses may result in a misleading biological interpretation. Autocorrelation between relocations is not undesirable: it contains information about ecological processes that should be integrated in habitat selection analyses.     

东北商品粮基地粮食生产的区域分异

论文以商品粮基地县为研究单元,运用数理统计和GIS空间分析结合的方法,揭示东北商品粮基地县粮食总产的区域差异。研究结果表明:①粮食总产低于平均水平的商品粮基地县占多数,高于平均水平的基地数量仅占36.36%,但粮食产量占全部基地县粮食总产量的64.74%;②粮食生产基本上形成了以玉米、大豆、水稻为主的生产能力格局,粮食总产的区域差异小于分品种粮食作物内部的区域差异;③从省域尺度看,粮食总产高于平均水平的基地县84.6%分布在黑龙江和吉林两省,粮食生产布局的区域化、专业化趋势明显,大宗粮食作物进一步向产粮大县集中;④从区域尺度看,粮食总产的空间格局高低交错,集中在以松嫩平原中部黑土区、辽河平原和三江平原为重心的平原地区,有由中部平原地区向周边递减的趋势。回归分析表明,播种面积的区域差异是导致商品粮基地县粮食总产区域分异的主要原因,农业现代化水平对其具有重要影响。应加强商品粮基地建设,加大中低产田的改造力度,走以提高粮食单产来提高粮食综合生产能力的内涵式发展道路。     

The imperiled fish fauna in the Nicaragua Canal zone

Large‐scale infrastructure projects commonly have large effects on the environment. The planned construction of the Nicaragua Canal will irreversibly alter the aquatic environment of Nicaragua in many ways. Two distinct drainage basins (San Juan and Punta Gorda) will be connected and numerous ecosystems will be altered. Considering the project's far‐reaching environmental effects, too few studies on biodiversity have been performed to date. This limits provision of robust environmental impact assessments. We explored the geographic distribution of taxonomic and genetic diversity of freshwater fish species (Poecilia spp., Amatitlania siquia, Hypsophrys nematopus, Brycon guatemalensis, and Roeboides bouchellei) across the Nicaragua Canal zone. We collected population samples in affected areas (San Juan, Punta Gorda, and Escondido drainage basins), investigated species composition of 2 drainage basins and performed genetic analyses (genetic diversity, analysis of molecular variance) based on mitochondrial cytb. Freshwater fish faunas differed substantially between drainage basins (Jaccard similarity = 0.33). Most populations from distinct drainage basins were genetically differentiated. Removing the geographic barrier between these basins will promote biotic homogenization and the loss of unique genetic diversity. We found species in areas where they were not known to exist, including an undescribed, highly distinct clade of live bearing fish (Poecilia). Our results indicate that the Nicaragua Canal likely will have strong impacts on Nicaragua's freshwater biodiversity. However, knowledge about the extent of these impacts is lacking, which highlights the need for more thorough investigations before the environment is altered irreversibly.     

基于时间序列MODIS数据的贵州省森林物候地域分异

森林物候是气候与环境变化的重要指示器,对于陆地植被生态环境监测具有重要的意义。以2011～2013年的MODIS NDVI(归一化植被指数)为时间序列数据,采用Savizky-Golay(S-G)滤波平滑和动态阀值法,提取出贵州省2012年森林物候的生长起始日期(SOS)、生长结束日期(EOS)、生长季长度(LOS)和生长季振幅(AOS)4个参数,分别将提取的森林物候参数与经度、纬度和海拔做相关性分析。研究结果显示:(1)贵州省森林物候参数与纬度相关性整体较弱,因此贵州省森林物候纬度地带性地域分异的不显著;(2)贵州省森林物候生长起始期、生长季长度与经度呈极显著相关,而森林物候生长结束期与经度呈低度相关,整体上贵州省森林物候参数海陆(经度)地带性地域分异显著;(3)贵州省森林物候生长起始期、生长结束期与海拔呈显著相关,而森林物候生长季长度与海拔呈极显著相关,因此贵州省森林物候参数垂直(海拔)地带性地域分异的十分显著。     

基于场理论的沪苏浙皖地区旅游空间差异研究

区域旅游供给场是一种重要的旅游场类型,场叠加、场结构与场核的作用效应是区域旅游供给场研究的核心内容。在对区域旅游供给场相关概念进行定义与空间解析的基础上,以游客密度作为旅游场强变量,运用GIS技术对由沪苏浙皖这一区域的空间差异进行了模拟和分析,研究结果表明:(1)随着旅游业的发展,区域旅游场的场域分异更为显著,但游客密度的集中程度在下降;(2)区域旅游场内存在较明显的"三阶梯"等级结构特征,且在考察末期,第一阶梯和第二阶梯场域范围不断扩大,尤以第二阶梯的扩大最为明显;(3)由场核向外围随着距离的增加,旅游场强呈现出显著的衰减特征,各次级场域的场核间也存在明显的场强波动地带;(4)区域旅游场极化、扩散作用并存,上海这一区域型场核在极化作用的同时在东西方向上对区域旅游场的扩散作用明显,但其扩散作用强度仍有待提高。     

Biodegradable dissolved organic carbon shapes bacterial community structures and co-occurrence patterns in large eutrophic Lake Taihu

Interactions between dissolved organic matter (DOM) and bacteria are central in the biogeochemical cycles of aquatic ecosystems; however, the relative importance of biodegradable dissolved organic carbon (BDOC) compared with other environmental variables in structuring the bacterial communities needs further investigation. Here, we investigated bacterial communities, chromophoric DOM (CDOM) characteristics and physico-chemical parameters as well as examined BDOC via bioassay incubations in large eutrophic Lake Taihu, China, to explore the importance of BDOC for shaping bacterial community structures and co-occurrence patterns. We found that the proportion of BDOC (%BDOC) correlated significantly and positively with the DOC concentration and the index of the contribution of recent produced autochthonous CDOM (BIX). %BDOC, further correlated positively with the relative abundance of the tryptophan-like component and negatively with CDOM aromaticity, indicating that autochthonous production of protein-like CDOM was an important source of BDOC. The richness of the bacterial communities correlated negatively with %BDOC, indicating an enhanced number of species in the refractory DOC environments. %BDOC was identified as a significant stronger factor than DOC in shaping bacterial community composition and the co-occurrence network, suggesting that substrate biodegradability is more significant than DOC quantity determining the bacterial communities in a eutrophic lake. Environmental factors explained a larger proportion of the variation in the conditionally rare and abundant subcommunity than for the abundant and the rare bacterial subcommunities. Our findings emphasize the importance of considering bacteria with different abundance patterns and DOC biodegradability when studying the interactions between DOM and bacteria in eutrophic lakes.     

基于“三生”视角的中国林地分类提取

林地具有多重功能,在生态优先区和生产生活区承担不同功能。传统林地分类难以兼顾区域主导功能和开发保护定位,且对不同功能区内林地的时空特征尚缺乏定量刻画。建立基于“生产—生活—生态”视角的林地分类,利用土地利用图、功能区划、植被物候特征和统计数据,使用专题图叠加、遥感识别和决策树分类技术,提取林地各类型。结果表明:2018年中国林地遥感面积为228.18万km ²,1990—2018年生态优先区域林地减少2.49万km ²,2000年后降速变缓;防风固沙、水源涵养和土壤保持区等核心生态功能区内局部林地增加,主要位于内蒙古部分草原和沙区、河北西北部和黄土高原;东北地区、西南喀斯特区和新疆北部的林地转换为耕地和草地,生物多样性保护区内林地降幅最小;用材林地在2010年后减少变缓,园地扩大主要来自东南地区的耕地和用材林,城市林地在广东、浙江、江苏和北京迅速增加。研究表明,发挥核心生态功能的林地在生态修复工程范围和自然保护区内局部恢复,但剧烈的人为扰动仍导致其面积整体降幅较大。建议分区域差异化恢复生态林地、提升主导生态价值。     

安徽省O3浓度时空分异及其驱动因素研究

基于2017—2018年安徽省132个空气质量监测站点的O₃浓度观测数据及各月份的气象与前体物排放数据, 采用空间自相关分析、地理探测器等方法分析安徽O₃浓度的时空分异及其驱动因素. 结果表明:安徽O₃浓度的峰值出现在5月和6月, 超标率分别为31.4%和42.8%. O₃浓度整体呈空间集聚特征, 高值区主要出现在安徽东北部的蚌埠、宿州、淮南和滁州4市, 低值主要分布在皖南山区. 气象要素是安徽省O₃浓度格局形成的主控因素, 其中6月的边界层高度(q=0.644)、近地面太阳辐射(q=0.597)和风速(q=0.571)的影响最大, 且呈正向影响, 风速的增大和边界层高度的增加可能使得输入性污染增加. 降雨量(q=-0.532)和相对湿度(q=-0.559)呈负向影响, 且降雨带的移动是影响安徽夏季O₃分布格局的一项关键因素. 本地前体物排放对安徽O₃浓度的影响受到气象要素的驱动, 在夏季呈正向, 而冬季呈反向, 其中CO的影响相对较大. 6月气象要素与本地前体物排放的双因子交互驱动对O₃浓度的空间分异具有增强作用. 边界层高度和近地面太阳辐射与本地前体物的组合解释力均大于0.7, 在不利的气象条件下, 应进一步加强对本地前体物排放的管控.     

差异化开展国土空间生态修复的思考

近年来,由于气候变化和人类活动的双重影响,生态系统承受了越来越大的压力。在一定程度上,这些压力改变了生态系统的结构和过程,降低了生态系统服务功能,对区域可持续发展形成了威胁。国土空间生态修复是推进生态文明建设的重大举措,也是应对以上生态系统问题的重要手段,我国已将其上升到国家战略的高度。但是,目前国土空间生态修复的相关研究尚缺乏系统的梳理,相关的国土空间生态修复工作也缺乏系统总结,不利于生态修复工作的深入开展。因此,亟需系统梳理我国生态修复相关工作的演进脉络,阐述不同时期国土空间生态修复目标、手段、区域的差异化,剖析当前我国开展国土空间生态修复工作遇到的问题,进而提出相关应对策略,以期裨益于我国新时期的国土空间生态修复工作。研究表明：（1）我国的生态修复研究经历了萌芽、早期实践及新时期国土空间生态修复的演进过程。各个时期生态修复目标、手段和区域的差异化明显。（2）当前,我国国土空间生态修复的主要问题是,生态方面的历史欠账多、现实矛盾多,生态系统功能问题较为突出,生态修复部门职责相对分散、履职较为矛盾,生态修复投入机制相对单一。（3）未来,应该分别依据生态问题时间维度、空间维度、行政与市场维度的差异化,分别开展有针对性的国土空间生态修复工作。     

重庆市五大功能区差异化环境保护政策研究

5大功能区战略是重庆坚持主体功能区规划理念,优化人口、产业和城镇发展布局,实现全市资源配置最优化和整体功能最大化的重要举措。该战略的实施对环境管理提出了新的任务和要求,构建有利于促进5大功能区建设的配套环境保护政策意义重大且非常迫切。本文在全面分析各功能区生态环境压力、发展定位和环境保护目标的基础上,遵循"分类指导、分区推进"原则,构建了5大功能区差异化环境保护政策框架,突出了生态红线、环境准入、总量控制、环境标准、环境监管、环境经济政策、绩效考核7大政策在不同功能区的政策取向和实施重点,有利于发挥环境保护政策的激励和约束作用。