太子河着生藻类群落与氮、磷营养盐的定量关系研究

着生藻类是河流水生生物群落的重要组成部分,其与栖境水环境因子有着紧密的关联性。国内外关于着生藻类群落与栖息地环境因子关系的研究多是通过多元统计分析,评价影响着生藻类群落时空分布的环境要素,这种定性分析仅能判断环境驱动因子,而无法精确定量着生藻类群落与环境因子(如氮、磷)的响应关系。本研究以辽宁省太子河为范例,基于3次全流域的水生态调查所获得的141个站位的生态数据,运用临界指示物种分析法(TITAN)和加权平均回归分析(WA),定量评价着生藻类群落与河流水环境中氮、磷营养盐的定量响应关系(最适值和阈值)。结果表明,采用TITAN在太子河共确定了22种总氮(TN)指示物种,其中,13种为负响应物种,9种为正响应物种。TN负响应指示种中,普通等片藻(Diatoma vulgare)为出现频数较高的物种; TN正响应指示种中,小片菱形藻(Nitzschia frustulum)出现的频数最高。TITAN确定的太子河流域总磷(TP)指示物种为19种,其中,9种为负响应物种,10种为正响应物种。TP指示种中,负响应种近缘桥弯藻(Cymbella affinis)出现频数最高,TP指示种所对应的正响应突变点中,小片菱形藻和急尖舟形藻(Navicula cuspidata)出现频数最高。总体上看,太子河TN和TP对着生藻类最适值范围分别为0.025～0.47 mg·L~(-1)和0.65～12.14 mg·L~(-1),直链藻属(Melosira)和菱形藻属(Nitzschia)的种类,适宜栖息于TP较高的水环境中;异极藻属(Gomphonema)和桥弯藻属(Cymbella)适宜栖息于TP较低的水环境中;裸藻属(Euglena)和菱形藻属(Nitzschia)适宜栖息于TN较高的水环境中;而桥弯藻属和舟形藻属(Navicula)适宜栖息于TN较低的水环境中。通过定量分析水环境因子氮、磷对着生藻类群落的最适值和阈值,可以相对准确地评估着生藻类群落与河流营养盐含量的定量响应关系,对于在太子河开展对氮、磷等典型营养物的流域"污染物"排放的总量控制等流域生态管理决策和环境保护提供基础数据和科学依据。     

Multiyear monitoring of survival following mitigation-driven translocation of a long-lived threatened reptile

Translocation is used by managers to mitigate the negative impacts of development on species. Moving individuals to a new location is challenging, and many translocation attempts have failed. Robust, posttranslocation monitoring is therefore important for evaluating effects of translocation on target species. We evaluated the efficacy of a translocation designed to mitigate the effects of a utility-scale solar energy project on the U.S. federally listed Mojave desert tortoise (Gopherus agassizii). The species is a long-lived reptile threatened by a variety of factors, including habitat loss due to renewable energy development in the Mojave Desert and portions of the Colorado Desert in southern California (southwestern United States). We translocated 58 individual tortoises away from the project's construction site and intensively monitored them over 5 years (2012–2017). We monitored these individuals and tortoises located in the translocation release area (resident tortoises; n = 112) and control tortoises (n = 149) in a nearby location. We used our tortoise encounter data and known-fate survival models to estimate annual and cumulative survival. Translocated tortoises in each of 2 size classes (120–160 mm, >160 mm) did not survive at lower rates than resident and control tortoises over the study period. For models with different sets of biotic and abiotic covariates, annual and cumulative estimates of survival were always >0.87 and >0.56, respectively. Larger tortoises tended to have higher survival, but translocated tortoises were not differentially affected by the covariates used to model variation in survival. Based on these findings, our translocation design and study protocols could inform other translocation projects for desert species. Our case study highlights the benefits of combining rigorous scientific monitoring with well-designed, mitigation-driven management actions to reduce the negative effects of development on species of conservation concern.     

An exploration of the relationships betweenmacroinvertebrate community composition and physical andchemical habitat characteristics in farm dams

Recently, Australian interest in farm dams has focused on rates of harvest of surface waters (runoff), and the impact this has on nearby natural systems. Little research has been directed towards the role of these artificial water bodies in sustaining biological reserves within the wider ecosystem. Macroinvertebrate communities in three farm dams in the Central Tablelands of New South Wales were surveyed, and water quality variables were correlated with species richness and abundance. Community responses to habitat factors including sediment depth, stock use, vegetation and debris were also examined. Communities were described at several taxonomic levels in addition to allocation to trophic groups and primary functional feeding groups.Species richness and abundance of communities were found to vary between dams and between habitat types within dams. The extent of these differences was decreased when communities were described by either trophic status or functional feeding mechanisms. Habitats were influenced by water quality and by physical features of the habitat, with the two factors interacting to define equilibrium conditions. Localised conditions resulted in different macroinvertebrate communities. Physicochemical parameters that correlated most closely with communities included light penetration, chlorophyll-a and conductivity. Habitat factors that were most frequently linked with communities were sediment depth and canopy cover, with localised disturbances related to stock use affecting feeding groups rather than specific taxa.One of the major problems associated with increasing modification of landscapes by agriculture or urbanisation is the fragmentation of undisturbed habitats. Creation of joint aquatic and woodland habitats enhances biodiversity corridors. The recognition of the potential for farm dams as reservoirs of biodiversity and development of management practices that optimise this neglected biodiversity reserve may have much wider benefits biologically, aesthetically and productively.     

Habitat evaluation of wild Amur tiger (Panthera tigris altaica) and conservation priority setting in north-eastern China

The Amur Tiger (Panthera tigris altaica) is one of the world’s most endangered species. Recently, habitat fragmentation, food scarcity and human hunting have drastically reduced the population size and distribution areas of Amur tigers in the wild, leaving them on the verge of extinction. Presently, they are only found in the north-eastern part of China. In this study, we developed a reference framework using methods and technologies of analytic hierarchy process (AHP), remote sensing (RS), geographic information system (GIS), GAP analysis and Natural Break (Jenks) classification to evaluate the habitat and to set the conservation priorities for Amur tigers in eastern areas of Heilongjiang and Jilin Provinces of northeast China. We proposed a Habitat Suitability Index (HSI) incorporating 7 factors covering natural conditions and human disturbance. Based on the HSI values, the suitability was classified into five levels from the most to not suitable. Finally, according to results of GAP analysis, we identified six conservation priorities and designed a conservation landscape incorporating four new nature reserves, enlarging two existing ones, and creating four linkages for Amur tigers in northeast China. The case study showed that the core habitats (the most suitable and highly suitable habitats) identified for Amur tigers covered 35,547 km², accounting for approximately 26.71% of the total study area (1,33,093 km²). However, existing nature reserves protected only (7124 km² or) 20.04% of the identified core habitats. Thus, enlargement of current reserves is necessary and urgent for the tiger’s conservation and restoration. Moreover, the establishment of wildlife corridors linking core habitats will provide an efficient reserve network for tiger conservation to maintain the evolutionary potential of Amur tigers facing environmental changes.     

甘肃兴隆山自然保护区濒危马麝(Moschus sifanicus)秋季利用生境特征

于2006~2007年9~10月间采用样线样带法研究了甘肃兴隆山自然保护区马麝的秋季生境利用特征,共布设286个空白对照样地和55个利用样地,测量并比较两类样地内的海拔等17个生境变量.结果表明,马麝秋季利用样地的乔木密度(0.90±0.14)和灌木均高(1.92 m±0.53 m)显著低于非利用样地(乔木密度1.35±0.07;灌木均高3.01 m±0.53 m),而且距水源距离(<1 000 m,76.37%)和人为干扰活动距离(<1 000 m,76.36%)较近的中下坡位生境(82.82%)(P<0.05).对喜好生境变量的主成分分析表明,地理因子(由海拔、水源距离、植被类型和坡向构成)是制约兴隆山马麝秋季栖息地选择的首要因子,此外,郁闭度因子(由郁闭度和坡度构成)、食物因子(由食物多度和乔木胸径构成)和隐蔽因子(由隐蔽度和避风性构成)也是影响兴隆山马麝秋季生境选择的重要因素.由于秋季对食物和水源的强烈选择,兴隆山马麝对生境隐蔽性和距人为干扰距离的选择强度较低,即承受较大强度的人为干扰.表5参31     

Negative Effects of Habitat Loss on Survival of Migrant Warblers in a Forest Mosaic

Abstract: Habitat loss and fragmentation in forested landscapes often negatively affect animal abundance; however, whether these factors also affect fitness is not well known. We hypothesized that observed decreases in bird occurrence and abundance in landscapes with harvested forests are associated with reduced apparent survival of adults. We defined apparent survival as an estimate of survival that accounts for an imperfect resighting probability, but not permanent emigration (i.e., dispersal). We examined the association between spatially extensive habitat loss and apparent survival of males of 2 Neotropical migrant species, Blackburnian Warbler (Dendroica fusca) and Black‐Throated Green Warbler (D. virens), over 7 years in the Greater Fundy Ecosystem, New Brunswick, Canada. We estimated apparent survival among and within breeding seasons. We quantified amount of habitat in the context of individual species. In this landscape, boundaries between land‐cover types are gradual rather than clearly identifiable and abrupt. Estimated apparent within‐season survival of both species decreased as a function of amount of habitat within a 2000‐m radius; survival was approximately 12 times (95% CI 3.43–14) greater in landscapes with 85% habitat than in landscapes with 10% habitat. Apparent annual survival also decreased as a function of amount of habitat within a 100‐m radius. Over the range of habitat amount, apparent annual survival decreased 15% (95% CI 7–29%) as the amount of habitat decreased. Our results suggest that reduced species occurrence in landscapes with low proportions of habitat is due partly to lower apparent survival at these sites. This mechanism operates both directly (i.e., via effects on mortality or dispersal during breeding) and possibly through indirect effects during the nonbreeding season. Habitat loss was associated not only with a lower number of individuals, but also with lower survival of those individuals.     

太子河洛氏鱥幼鱼栖息地适宜度评估

基于对太子河流域鱼类及栖息地的调查研究,选择该流域的优势种洛氏鱥(Phoxinus lagowskii)作为指示生物,建立洛氏鱥幼鱼对水深、流速、溶解氧、总溶解颗粒物和河岸带植被指数的栖息地适宜度曲线,并借鉴河道内流量增量法计算各采样点河段的洛氏鱥幼鱼栖息地适宜度指数。结果表明:洛氏鱥幼鱼栖息地适宜度指数在太子河上游较高(>0.5),中游次之(0.2-0.5),下游较低(<0.2)。洛氏鱥幼鱼栖息地适宜度指数与10项栖息地调查指标和土地利用类型的相关性分析表明:太子河流域内限制洛氏鱥幼鱼生存的因素不是水文条件,而是河流水质及河岸带等环境因素;洛氏鱥幼鱼栖息地适宜度指数受人类活动影响较大,随着太子河中下游人类开发强度加大,洛氏鱥栖息地质量呈下降趋势。     

Promoting Large,Compact Mature Forest Patches in Harvest Scheduling Models

Spatially explicit harvest scheduling models that can promote the development of dynamic mature forest patches have been proposed in the past. This paper introduces a formulation that extends these models by allowing the total perimeter of the patches to be constrained or minimized. Test run results suggest that the proposed model can produce solutions with fewer, larger, and more compact patches. In addition, patches are more likely to be temporally connected with this formulation. Methods for identifying the tradeoffs between the net present value of the forest and the size and perimeter of the evolving patches are demonstrated for a hypothetical forest.     

水电大坝扰动与栖息地质量变化——以漫湾电站为例

分析了水电大坝建设对栖息地影响的原理和时空特征,在此基础上选取了水电大坝对栖息地影响的主要指标,建立了大坝对上游库区和坝下栖息地影响的评价指标体系.并以云南省澜沧江干流上的漫湾电站为例,通过对漫湾电站建坝前后各个栖息地指标变化率的分析和集成,探讨了漫湾电站的建设和运营对库区和坝下栖息地的影响,并确定了影响强度.研究结果表明,漫湾大坝对上游栖息地的髟响强度值为0.53,对下游栖息地的影响强度值为0.37,即短期时间内,对上游库区栖息地的影响大于对坝下栖息地的影响;对上游栖息地影响最大的是栖息地连续性(1.00)和栖息地面积(0.58);对下游栖息地影响最大的是栖息地连续性(0.68)和稳定性(0.65).     

喀斯特高原黄壤区退化植物群落常见植物叶片氮同位素组成

氮是植物需求量最大的矿质营养元素。由于氮循环诸过程中的化学转化、物理运输等都有可能使其发生同位素分馏,植物稳定氮同位素组成是土壤-植物-大气连续体综合作用的整体响应,能较好的反映流域内与植物生理生态过程相联系的一系列环境信息,具有示踪、整合和指示等多项功能。为探讨喀斯特环境下黄壤区植物稳定氮同位素组成变异的影响因素及其相关关系,以喀斯特高原贵州省清镇市王家寨峰丛洼地小流域为例,选取流域内黄壤区退化植物群落3种植被类型中的4种常见植物为研究对象,分别对其叶片C、N、P、K、Ca、Mg元素含量和稳定氮同位素进行了测定分析。结果表明:(1)研究区植物叶片δ~(15)N值的变化范围为-3. 25‰～0. 69‰,平均值为-1. 04‰,变异程度较高,离散程度较大,呈负偏态分布。(2)植物叶片δ~(15)N值在群落间和坡位间的差异均不显著(P0. 05);(3)植物叶片δ~(15)N值的种间变化趋势为小果蔷薇(-0. 03‰)火棘(-0. 24‰)过路黄(-1. 58‰)粉枝莓(-2. 29‰),差异显著(P0. 05)。(4)研究区植物叶片δ~(15)N值受群落类型和物种因素的交互影响显著(P=0. 016,R2=0. 870)。(5)研究区植物叶片δ~(15)N值受叶片K营养含量的影响较大,同时与C、N、P、K、Ca元素化学计量比之间的关系密切,叶片K、Ca营养含量间的调控是影响黄壤区植物叶片δ~(15)N值的主要因素。