Fuzzy Rough Set algorithm with Binary Shuffled Frog-Leaping (BSFL-FRSA): An innovative approach for identifying main drivers of carbon exchange in temperate deciduous forests

The spatial variability, driving forces, and uncertainties of the net ecosystem exchange (NEE) of carbon between the temperate forests and the atmosphere remain elusive. Here, we proposed a fuzzy rough set algorithm with binary shuffled frog leaping (BSFL-FRSA) to identify main driving variables and define the contribution rate of main drivers to NEE. As a case study, we applied the approach to nine deciduous forest eddy covariance flux sites in the northeastern United States. The results show that the BSFL-FRSA effectively retained most information using just a few variables, and it performed better than the GA-FRSA (fuzzy rough set with genetic algorithm). Temperature, radiation, and soil water content were identified as the most influential variables (impact in descending order) to NEE across all sites. Soil temperature was the most important variable explained 59.6% of the NEE variance. Soil temperature and net radiation together, explained 72.7% of the NEE variance, was the most important two variables among all possible two-variable combinations. The most influential three variables on NEE among all possible three-variable combinations were soil temperature, net radiation, and soil water content or relative humidity (explained 81.1% of the NEE variance). The variance attribution approach presented here is generic and can be applied to other studies; the dominant influence of soil temperature begs for accurate characterization of soil temperature dynamics in time and space particularly in the global warming context.     

The filamentous fungal pellet and forces driving its formation

Filamentous fungi play an important role not only in the bio-manufacturing of value-added products, but also in bioenergy and environmental research. The bioprocess manipulation of filamentous fungi is more difficult than that of other microbial species because of their different pellet morphologies and the presence of tangled mycelia under different cultivation conditions. Fungal pellets, which have the advantages of harvest ease, low fermentation broth viscosity and high yield of some proteins, have been used for a long time. Many attempts have been made to establish the relationship between pellet and product yield using quantitative approaches. Fungal pellet formation is attributed to the combination of electrostatic interactions, hydrophobicity and specific interactions from spore wall components. Electrostatic interactions result from van der Waals forces and negative charge repulsion from carboxyl groups in the spore wall structure. Electrostatic interactions are also affected by counter-ions (cations) and the physiologic conditions of spores that modify the carboxyl groups. Fungal aggregates are promoted by the hydrophobicity generated by hydrophobins, which form a hydrophobic coat that covers the spore. The specific interactions of spore wall components contribute to spore aggregation through salt bridging. A model of spore aggregation was proposed based on these forces. Additionally, some challenges were addressed, including the limitations of research techniques, the quantitative determination of forces and the complex information of biological systems, to clarify the mechanism of fungal pellet formation.     

西南地区道路建设对植被净初级生产力的影响

道路建设促进区域社会经济发展的同时,通过直接改变原有生态系统、间接增强人类活动进而改变原有生态系统的途径对周围生态系统产生影响。定量评估道路建设对植被净初级生产力(Net Primary Productivity,NPP)的影响对掌握线性工程生态环境影响,进行社会经济发展与生态安全权衡具有一定现实意义。基于西南地区2016年道路和2015年NPP数据,利用核密度(Kernel Density,KD)表征道路影响域和影响强度,借助ArcGIS平台,分析不同土地覆被和经济发展强度下道路建设与NPP的关系。结果表明:(1)搜索半径为0.5km时,道路KD (km/km²)范围为[0.0,47.3],其中道路KD为零的区域约占研究区总面积的79.8%,这些未受道路干扰区域大部分位于西藏、青海、四川西部、贵州和云南的西北部;道路KD为(0.0,5.0\]的区域约占道路KD非零区域面积的88.4%,除成都、重庆、贵阳、南宁、昆明等城市外,区域大部分地区道路密度仍处于较低水平。(2)从不同土地覆被下道路KD与NPP的关系来看,中低道路干扰条件下,林地、耕地和人工表面稳定性更强,道路KD小于4.1时NPP相对稳定,而草地、湿地和其他土地覆被在道路KD大于2.1后,NPP出现急剧变化。随道路KD增大NPP趋于发散,这可能是由道路密度增加后其两侧人类干扰类型多样化引起。(3)以县级行政区划为单位,按单位面积道路KD由小到大的顺序,将研究区分成5个部分:分区1-分区5。在分区1,NPP随道路KD增大呈先波动升高,相对稳定变化后降低再发散;在分区2-分区5,NPP随道路KD增大总体呈降低趋势,且变异性逐渐增加,经历了相对稳定阶段、线性变化阶段、发散阶段。根据研究结果,道路建设需重点关注生态敏感脆弱区的植被保护,如草地和湿地,应尽量避免较高密度道路建设带来的生态系统退化问题,同时应根据不同的地区制定适宜的保护方案。     

Do trappers understand marten habitat?

Previous studies of the effects of fur trapping on marten populations have not considered habitat variation and how trappers use available habitat. We investigated the behavior of fur trappers with respect to roads, waterways, and the forest habitats on trap lines, using registered trap lines in northern Ontario as a study system. The objectives of this study were to 1) develop models for predicting trap location based on access and habitat features, 2) determine whether trappers target the same habitat preferred by American marten, and 3) investigate effects of spatial resolution on predictive models, using a geographic information system (GIS) for coarse resolution variables and direct forest mensuration for fine resolution variables. Distance to roads and water were by far the most influential factors in logistic models for predicting trap presence, accounting for 51.2–61.7% of the observed deviance. At a coarse spatial resolution, trappers selected sites that were close to vehicular access, and in older mixed wood forest stands. Similarly, at a coarse resolution, marten selected old stands, but dominated by coniferous trees. At a finer spatial resolution, trappers selected sites with high basal area of trees, pronounced proportion of black spruce, high canopy cover, and high density of coarse woody debris, consistent with previous studies on marten habitat selection at a fine resolution. Although coarse resolution models are easily applicable because of the wide availability of GIS land cover data, fine resolution models had greater predictive power when considering habitat variables. By quantifying trapper behaviors, these results suggest that the effectiveness of marten sanctuaries used in forest management depend not only on the age and species composition of forest stands left unlogged, but also on the degree to which they are accessible to trappers. © 2012 The Wildlife Society.     

Fate of Heavy Metal Contaminants in Road Dusts and Gully Sediments in Guangzhou,SE China: A Chemical and Mineralogical Assessment

The urban environment of Guangzhou, the largest industrialized center in SE China, has elevated levels of heavy metals. In places, Cu, Pb, and Zn contents exceed 490, 920, and 1,820 mg/kg, respectively. The accumulation of these contaminants is likely to accelerate as a consequence of rapid economic and industrial growth in the region. Understanding of the possible fate of the contaminants is therefore imperative in order to assess their potential long-term ecological impacts. This article documents the results of a sequential extraction procedure involving five operationally defined fractions to determine the chemical partitioning of Cu, Pb, and Zn in the urban deposits represented by road dusts and corresponding gully sediments. Special emphasis was given to the mineralogical characteristics of the urban deposits. Road dusts were mainly composed of quartz, K-Feldspar, plagioclase, and calcite, and contained minor amounts of mica and clay minerals. The corresponding gully sediments, however, typically contained minor amounts of calcite, mica, and clay minerals, and were dominated by quartz and K-feldspar. The road dusts and gully sediments exhibited comparable chemical partitioning patterns of Cu, Pb, and Zn, despite significant differences in the relative abundances of minerals, especially of calcite. Lead and Zn occurred mainly in the operationally defined carbonate/ specifically adsorbed (Pb: 48%; Zn: 50%) and Fe-Mn (Pb: 36%; Zn: 27%) phases, whereas Cu was largely associated with the organic (70%) and residual (15%) phases. In general, the residual phases of the heavy metal contaminants were equal or less than 15%, suggesting their dominantly anthropogenic origin. The relative mobility and bioavailability of the heavy metals in the urban deposits of Guangzhou was: Pb ～ Zn > Cu. The ever-increasing accumulations of heavy metals may pose a threat in the region both to the environment and to human health.     

基于网络K函数的西双版纳人工林空间格局及动态

区域植被格局的分布特征受诸多要素影响,但其空间格局和动态具有一定规律或自相关性,道路网络作为景观中显著的人工线性要素,在很大程度上影响着区域的植被格局特征,特别是人工植被的分布特征.运用网络K函数,分析了道路网络和人工林空间格局分布的相互关系,并且用二元网络K函数研究了人工林扩展对针叶林和阔叶林的影响.结果表明:人工林在1970-2000年间种群分布格局有非常明显的变化,特别是从1990到2000年,种群面积不断扩大,主要从北部地区扩展到西北和东南地区.1970-1990年人工林扩展主要集中在低海拔的道路网络附近,沿道路网络呈现明显的集聚分布,公路效应明显.但后期逐渐向距公路较远、海拔较高的地区扩展,到2000年在大尺度下人工林斑块呈显著随机分布.同时,人工林面积的增长对针叶林影响显著,对阔叶林有影响但是并不显著.二元网络K函数表明,在1970到1990年人工林与针叶林沿道路网络在小尺度为负关联,在局部地区存在着竞争,但在大尺度上对环境条件的要求具有一致性为正关联.到2000年,在大尺度上人工林与针叶林的种群分布格局呈显著负相关,人工林面积的不断扩展导致了针叶林面积的下降.     

重大工程影响下新疆卡拉麦里山有蹄类野生动物自然保护区鹅喉羚的生境格局变化

生境评价对物种保护具有重要意义。鹅喉羚(Gazella subgutturosa)是新疆卡拉麦里山有蹄类野生动物自然保护区的代表性物种, 开展其生境适宜性评价可以为该物种的保护和管理提供科学依据。作者基于2005-2019年采用样线法在保护区开展野外调查所获鹅喉羚的分布点数据, 利用最大熵(MaxEnt)模型筛选环境变量, 评估鹅喉羚在矿业开发前(2005年)、矿业开发顶峰时(2011年)和矿区生态修复后(2019年) 3个时期的生境质量; 采用质心转移和景观格局指数分析近15年鹅喉羚的生境空间格局变化特征。结果表明模型预测结果准确性较高, 3个时期鹅喉羚的潜在适宜生境面积波动较大, Jackknife检验结果表明在任一时期水源点对鹅喉羚生境选择的影响均最大。矿业开发前鹅喉羚适宜生境分布于保护区中部, 主要特征为面积大、生境斑块集中、破碎化程度低; 矿业开发顶峰时鹅喉羚的适宜生境面积较矿业开发前减少2.39%, 尤其是保护区南部大面积适宜生境丧失, 质心转移和景观格局指数分析结果显示适宜生境向保护区北部转移, 生境斑块离散破碎程度高; 实施矿区生态修复后鹅喉羚的适宜生境面积较矿业开发顶峰时增加了3.50%, 因矿业开发丧失的生境重新成为鹅喉羚的适宜生境。与2005年以前相比, 2019年鹅喉羚生境斑块仍离散化严重, 部分适宜生境因新修建的高速公路和铁路而重新丧失。基于以上研究结果, 我们从保护水源、控制交通建设、修复矿区和加强野生动物通道监测等4个方面对鹅喉羚种群保护管理提出了建议。     

Golden eagle use of winter roadkill and response to vehicles in the western United States

Vehicle collisions are a significant source of wildlife mortality worldwide, but less attention has been given to secondary mortality of roadkill scavengers, such as the golden eagle (Aquila chrysaetos). We sought to quantify golden eagle winter use of roadkill mammal carcasses and eagle flushing from vehicles in Oregon, Utah, and Wyoming, USA, as proxies for strike risk, using motion-sensitive cameras. We monitored 160 carcasses and captured 2,146 eagle–vehicle interactions at 58 carcasses (1–240 observations/carcass) during winters of 2016–2017, 2017–2018, and 2018–2019. We used generalized linear mixed models, which suggested that eagle use of carcasses declined with time since camera deployment but increased with distance to road. Flushing from vehicles decreased with carcass distance to road but was higher in the morning, in response to larger vehicles and vehicles in the closest lane, and in the Oregon study area. We suggest that roadkill distance to road is the easiest factor to manipulate with the dual benefits of increasing food availability to golden eagles and decreasing flush-related vehicle strike risk. We recommend that roadkill be moved at least 12 m from the road to increase eagle use and decrease flushing 4-fold relative to behavior observed at the road edge. Because flushing from roadkill is believed to be the primary cause of eagle–vehicle strikes, informed roadkill management has the potential to reduce human-caused mortality of golden eagles.     

海南热带雨林国家公园高速公路穿越段景观动态与生态风险评估

海南热带雨林国家公园被中线高速公路自东北-西南方向穿越,改变了局域景观分布格局,影响到生态系统完整性与原真性,可能存在潜在的生态风险。选取海南热带雨林国家公园高速公路穿越段两侧3 km作为研究区域,运用GIS技术、Fragstats和景观生态学理论定量评价2013年（高速公路未建）、2016年（高速公路在建）和2019年（高速公路竣工）三年的景观要素变化,解析景观变化趋势和可能带来的潜在生态风险。结果表明,2016年高速公路建成面积（含动土区域）为325.51 hm²,林地面积略有减少,但林地斑块密度增加;耕地面积虽略有增加,但耕地最大斑块指数下降,耕地景观优势度降低。2019年高速公路建成竣工后,由于路旁绿化,高速公路占地面积有所下降,林地面积和林地斑块密度增加,但林地和耕地斑块的内聚力指数下降,自然连通度略降低,破碎化程度加剧;高速公路穿越段中等生态风险区和较高生态风险区面积逐年增加。但隧道和高架桥路段在一定程度上维持了道路两侧的植被连通性,对局域生态系统没有明显影响。高速公路造成的生境隔离与破碎化可能累积产生远期的负面生态学效应。海南热带雨林国家公园高速公路穿越段位于生态敏感的水源涵养区,建议增设隧道式高架林地提升生境连通性和生态系统完整性、增加人工湿地汇聚和净化道路径流、设立长期生态监测样地对关键节点生态过程与生态系统功能特别是水源涵养与水质净化功能等开展监测与生态恢复。