A robust nonparametric method for quantifying undetected extinctions

How many species have gone extinct in modern times before being described by science? To answer this question, and thereby get a full assessment of humanity's impact on biodiversity, statistical methods that quantify undetected extinctions are required. Such methods have been developed recently, but they are limited by their reliance on parametric assumptions; specifically, they assume the pools of extant and undetected species decay exponentially, whereas real detection rates vary temporally with survey effort and real extinction rates vary with the waxing and waning of threatening processes. We devised a new, nonparametric method for estimating undetected extinctions. As inputs, the method requires only the first and last date at which each species in an ensemble was recorded. As outputs, the method provides estimates of the proportion of species that have gone extinct, detected, or undetected and, in the special case where the number of undetected extant species in the present day is assumed close to zero, of the absolute number of undetected extinct species. The main assumption of the method is that the per‐species extinction rate is independent of whether a species has been detected or not. We applied the method to the resident native bird fauna of Singapore. Of 195 recorded species, 58 (29.7%) have gone extinct in the last 200 years. Our method projected that an additional 9.6 species (95% CI 3.4, 19.8) have gone extinct without first being recorded, implying a true extinction rate of 33.0% (95% CI 31.0%, 36.2%). We provide R code for implementing our method. Because our method does not depend on strong assumptions, we expect it to be broadly useful for quantifying undetected extinctions.     

Large scale parameter study of an individual-based model of clonal plant with volunteer computing

Understanding clonal strategies (i.e. the ability of plants to reproduce vegetatively) is particularly important to explain species persistence. A clonal individual may be considered as a network of interconnected ramets that colonizes space. Resources in this network can be shared and/or stored. We developed an individual-based model (IBM) to simulate the growth of an individual clonal plant. Typically a realistic IBM requires a large set of parameters to adequately represent the complexity of the clonal plant growth. Simulations in the literature are often limited to small subsets of the parameter space and are guided by the a priori knowledge and with heuristic aims of the researcher. The aim of this paper was to demonstrate the benefit of volunteer computing in computational ecology to systematically browse the parameter space and analyze the simulation results in order to draw rigorous conclusions. To be specific, we simulated clonal plant growth using nine growth rules related to the metabolic process, plant architecture, resource sharing and storage and nineteen input parameters. We chose 2-4 values per input parameter which corresponded to 20 millions of combinations tested through volunteer computing. We used three criteria to evaluate plant performance: plant total resource, ramet production and maximum length of one branch. The 1% top-performing plants were sorted according to these criteria. Plant total resource and ramet production were correlated while considering the top-performing plants. The maximum length of one branch was independent from the other two performance traits. We detected two processes promoting at least one of the plant performance traits: (i) a relatively high metabolic gain (high photosynthetic activity and low production cost for new growth units), a low resource storage and long integration distance for resource sharing; (ii) short spacer lengths and the predominance of elongation of existing branches over branching. Interactive effects between parameter values were demonstrated for more than half of the input parameters. Best performance was reached for plants with slightly different combinations of values for these parameters (i.e. different strategies) rather than a single one (i.e. unique strategy). This modeling approach with volunteer computing enabled us to proceed to large-scale virtual experiments which provided a new quality of insight into ecological processes linked with clonal plant growth.     

城市湿地水生植物对附生轮虫多样性的影响

于2021年6~10月对海珠湿地连通水系水区及三类水生植物体表附生的轮虫群落结构开展研究,分析水生植物附生轮虫多样性及群落动态特征.研究期间共记录轮虫70种,其中水生植物水区最多,记录47种.水生植物均有大量轮虫附生,变化范围在108~5826ind./gdw之间,且附生轮虫丰度呈现沉水植物>浮叶植物>挺水植物的变化趋势.水生植物附生群落、无植物水区和水生植物栽培区3种生境轮虫群落物种组成差异明显.水生植物附生群落中游动能力较弱的腔轮虫、镜轮虫、鞍甲轮虫等敏感类群占据优势,而无水生植物区和水生植物水区群落中以游泳能力较强的多肢轮属、龟纹轮属和臂尾轮属等耐污类群占据优势.3类型水生植物附生轮虫群落Shannon-Weiner多样性指数与Pielou’s均匀性指数均显著高于无植物栽培水区(P<0.05).3类水生植物均为轮虫提供了生境支持,有效提高城市湿地生态系统生物多样性.     

Cu2+对活性污泥代谢及群落结构的影响

为探究微量Cu2+对微生物代谢产物及群落结构的影响,采用序批式反应器(SBR),以含Cu2+原水作用下活性污泥为研究对象,分析不同质量浓度Cu2对胞外聚合物(EPS)和溶解性代谢产物(SMP)的影响,并通过聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)技术分析总细菌在不同质量浓度微量Cu2+驯化前后的群落结构.结果表明,活性污泥的EPS质量浓度受Cu2+的影响呈波动下降趋势,反应中后期趋于稳定,稳定区间与Cu2+质量浓度成反比.Cu2+加入反应体系后会造成SMP质量浓度短暂下降,随后微生物释放SMP来缓解环境压力,SMP质量浓度有所回升;中后期由于Cu2+积累导致细胞自溶、释放SMP,SMP质量浓度突增,增长幅度与Cu2+质量浓度成正比.不同质量浓度Cu2+会造成特定菌群的消亡,还会促进耐受力强的微生物成为优势菌种.含Cu2+原水会使微生物量和群落多样性降低,当Cu2+质量浓度为3.5 mg/L时SDI由1.92下降至1.23,而由于新优势菌种的产生,Cu2+质量浓度为5.0 mg/L时SDI有所回升.     

大渡河老鹰岩河段的水生生物群落结构及水质评价

为了揭示大渡河老鹰岩河段的水生生物群落结构,沿河段自上而下对9个采样断面的藻类植物、浮游动物、底栖无脊椎动物、鱼类进行了采样分析;同时,结合河段实际情况利用专家打分法确定不同生物类群的权值,并通过创建的水质生物综合评价指数(comprehensive evaluation of water quality index,CEWI)对水质进行评价.结果表明:①大渡河老鹰岩河段共采集到藻类植物6门31科56属105种,其中硅藻的物种数量最为丰富;整个河段藻类植物的平均细胞密度为17.9978×10~4 ind·L~(-1),平均生物量为0.446 3 mg·L~(-1);龙头石、礼约河和小水河的藻类种群密度最高;②浮游动物有3门11科12属26种,其中原生动物门最为丰富,占80.77%;整个河段浮游动物的平均密度为40.89 ind·L~(-1),平均生物量为13.26×10~(-3)mg·L~(-1),整体群落组成较为简单,种类和数量偏少;③底栖无脊椎动物有6门14科14属14种,其中昆虫纲最为丰富,占57.16%;礼约河和小水河两条支流中的底栖动物相对分布较多;④水质整体CEWI均值为2.698 28,属轻度污染;各样点CEWI值与各单项水质评价指数间均呈极显著正相关,表现出高度的一致性;此外,松林河和南桠河属中度污染(1CEWI≤2),而礼约河和老鹰岩一级样点水质清洁(CEWI3);其中,松林河的水质最差,CEWI值最小,达1.620 7;而礼约河的水质最优,CEWI值最高,达3.954 5;其余样点水质均受到不同程度的轻度污染.     

铁岭市莲花湖湿地生物多样性评价研究

在对莲花湖湿地物种现状进行调查分析、监测及统计的基础上,建立湿地生物多样性评价指标体系与赋值标准,从物种丰富度、生态系统类型多样性、物种特有性、外来物种入侵度四个一级指标及十五个二级指标对莲花湖湿地生物多样性进行了评价。莲花湖湿地生物多样性总评分为67分,结果表明莲花湖湿地生物多样性处于优秀水平,应继续加强对莲花湖湿地生态环境的恢复和管理。研究结果将为相关管理部门提供决策依据,为莲花湖湿地生物多样性的保护和管理打下基础。     

淀粉废水处理系统中活性污泥的微生物群落结构及多样性分析

为探究淀粉废水处理活性污泥中微生物的群落结构及多样性,基于Illumina MiSeq高通量测序方法,分析了不同运行阶段的A/O处理系统中活性污泥的微生物群落与多样性组成.结果表明,A/O系统中处理淀粉生产废水的活性污泥在同一种废水下微生物群落结构总体比较稳定,优势细菌主要为变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)、绿弯菌门(Chloroflexi)、厚壁菌门(Firmicutes)和放线菌门(Actinobacteria)等;最重要优势细菌类群为变形菌门(45. 66%～66. 30%),其中γ-亚纲细菌是其主要成员,占比36. 38%～66. 65%.优势拟杆菌门主要成员鞘脂杆菌纲在污泥沉降性能较好时其占比下降,但绿弯菌门主要成员厌氧绳菌纲在污泥沉降性能较好时其占比明显增加,变化趋势正好相反,或许它们二者之间的耦合变化与污泥沉降性能变化密切相关.活性污泥样品中存在大量特殊功能菌群,它们在活性污泥的污染物分解和氮磷去除中发挥重要作用.     

Sustainability of wild plant use in the Andean Community of South America

Overexploitation is the second biggest driver of global plant extinction. Meanwhile, useful plant species are vital to livelihoods across the world, with global conservation efforts increasingly applying the concept of ‘conservation-through-use.’ However, successfully balancing conservation and biodiversity use remains challenging. We reviewed literature on the sustainability of wild-collected plant use across the countries of Colombia, Ecuador, Peru, and Bolivia—a region of global importance for its biological and cultural richness. After applying defined search terms and a two-stage screening process, 68 articles were reviewed. The numbers which reported sustainable, unsustainable, or context-dependent outcomes were relatively even, but national differences emerged. Through narrative synthesis, we identified five key, reoccurring themes: plant biology; land tenure; knowledge, resource, and capacity; economics and market pressures; and institutional structures, policy, and legislation. Our results show the need for flexible, context-specific approaches and the importance of collaboration, with bottom-up management and conservation methods involving local communities and traditional ecological knowledge often proving most effective. Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01529-7.     

Can environmental compensation contribute to socially equitable conservation? The case of an ecological fiscal transfer in the Brazilian Atlantic forest

ABSTRACT

Regions of high biodiversity often coincide with regions of poverty and conservation can imply economic and social costs for poor resident populations. Environmental compensation is considered a tool to reduce socio-environmental conflict, improve the equity of conservation and promote sustainable development. The intricacies of specific socio-ecological systems may determine how compensation payments are interpreted locally to produce outcomes. This research examines the social perceptions of an ecological fiscal transfer which intends to compensate the local public administration for the substantial costs of conservation in a hotspot of biological and social diversity in the Brazilian Atlantic forest. In this context we explore whether financial compensation (1) influences local perceptions of the conservation regime, (2) contributes towards the reconciliation of human-conservation conflicts and (3) triggers any meaningful socio-economic improvement that would counter the local costs of conservation. Results show that environmental compensation is not widely recognised as effectively benefiting the community. Local authorities consider compensation insufficient to enact a sustainable development agenda. Environmental compensation could play an important role in a policy mix for socially equitable conservation by being explicitly linked to community benefits, especially to fostering local livelihoods. The collaboration of actors operating across multiple governance levels may improve the institutional capacity of local actors to produce effective outcomes.