A test for interaction between brown trout (Salmo trutta) and inanga (Galaxias maculatus) in an artificial stream

Abstract –  The interaction between brown trout ( Salmo trutta ; fork length (FL) range 255–390 mm) and inanga ( Galaxias maculatus ; FL range 55–115 mm) was tested during summer through autumn in an artificial stream consisting of a single run-riffle-pool sequence with a natural food supply. Each experimental trial lasted for 15 days, and consisted of two brown trout and 50 inanga collected fresh from a nearby stream, with each species given prior residence in four replicate tests, totalling eight trials in all. In addition, two control trials (each 10 days), with 50 inanga in each, were run. Brown trout almost exclusively occupied the pool, whereas inanga occupied all habitat types, although in different proportions, when tested with and without brown trout. The proportion of inanga in the pool was appreciably lower in the experimental trials with brown trout than in the control trials with no brown trout; prior residence had no significant effect on inanga habitat use. Mortality of inanga attributable to predation by brown trout ranged from 0 to 40% with a mean of 14.5 ± 4.7%. The results suggest that habitat use and survival of inanga populations in small streams can be adversely affected by brown trout.     

东北春玉米全生育期气候适宜度评价

适宜的气候要素是保障东北春玉米健康生长和高产稳产的基本条件。依据温、光、水气候要素对春玉米生长的影响,分别构建温度、日照和降水适宜度模型,引入有效降水提高模型精度,再基于有效降水和实际降水将三种气候要素耦合建立综合气候适宜度模型Ⅰ和模型Ⅱ,并利用1994—2013年有效气象、物候数据和2003—2010年像元尺度大田玉米生长状况时序遥感监测信息对海伦和泰来两个典型东北农业台站进行模型测试检验,将最适用模型应用于东北三省玉米典型种植区以估算2008与2009年25个站点不同生育期各气候要素适宜度。检验结果表明,“基于有效降水的模型Ⅰ”所估算的全生育期综合气候适宜度与NDVI、EVI的相关系数(0.58、0.29)均优于“基于实际降水的模型Ⅱ”(0.52、0.18),融合有效降水信息的模型Ⅰ更能有效捕获气候要素对春玉米生长胁迫现象。应用结果显示,模型Ⅰ估算的2008和2009年东北春玉米全生育期综合气候适宜度分别为0.67和0.56,与该地区2008年春玉米实际产量高于2009年表现一致;两年间东北三省春玉米各气候要素适宜度总体表现为温度>日照>有效降水;辽宁与吉林的温度、有效...     

西藏日喀则地区马铃薯气候适宜度模型分析及其时空变化特征研究

基于日喀则地区7个国家气象站1980—2021年逐日气象数据,分析构建了高原马铃薯气温(T)、光照(S)、水分(W)、气候(C)适宜度评价模型并对其时空变化特征进行分析,结果发现：近42年日喀则地区S平均值为0.82,呈逐年弱下降趋势,T、W、C适宜度平均值分别为0.79、0.64、0.61,均呈逐年上升趋势;马铃薯全生育期的光热资源都在最合理区域(S、T≥0.7),满足了其长发育需求。W在播种～出苗期(W=0.62)、开花～成熟期(W=0.44)呈现较低水平,是制约日喀则地区马铃薯生长发育的最主要因素;T、S空间分布较均匀,且呈现自西向东、自南北向中递增趋势,W空间分布不均匀。桑珠孜区—南木林县一带地区为马铃薯综合气候适宜度高值区(C>0.6),适宜大力发展马铃薯产业。由本文建立的日尺度气候适宜度评价模型得出的年际变化和区域特征结果与实际情况比较一致,为了解气候变化下日喀则马铃薯生长发育适宜度的时空变化提供依据。     

深圳红火蚁蚁巢密度、社会型研究及防治效果评价

本文报道了深圳红火蚁生境类型与蚁巢密度的关系,社会型的鉴别以及应用茚虫威对多后型和单后型、多后型共存地区的防治效果。红火蚁的蚁巢密度（巢/100 m2）与生境类型密切相关,在所调查的5类生境中,待建地的蚁巢密度最高,为3.81巢/100 m2,公路边的次之,为2.95巢/100 m2,城市绿地的最低,为0.63巢/100 m2。应用多元PCR技术对6个行政区社会型进行鉴别的结果表明,福田、龙岗、南山区为多后型与单后型共存,单后型与多后型的比仅为1∶(3~4)。罗湖、宝安、盐田3区全部为多后型;多后型地区的蚁巢密度（2.2巢/100 m2）比单后型地区（1.9巢/100 m2）的为高,但没有显著差异;应用茚虫威进行防治60 d后的调查结果表明,多后型地区的防治效果（97.8%）比单后型地区（96.7%）的要好,但没有显著差异。最后,本文对这些结果产生的原因及应用价值进行了讨论。     

甘南夏河高寒草甸高原鼢鼠和高原鼠兔秋季栖息地特征

2010年至2014年连续5年对甘南夏河高寒草甸高原鼢鼠(Eospalax bailyei)和高原鼠兔(Ochotona curzoniae)的分布与其地形、植被因子等进行了调查,分析两小型哺乳动物秋季越冬前的栖息地利用特征。结果表明,其秋季栖息地利用与地形和植被特征显著相关。高原鼠兔易选择坡地、半阳坡和坡中位的地形,而高原鼢鼠易选择平地、阳坡和坡底位的地形;植被盖度是影响高原鼠兔分布的重要因子。地上生物量非中等的平地是两小哺乳动物共存的主要分布地,两小型哺乳动物的种群动态与植被盖度和生物量均显著相关(P0.05);鹅绒委陵菜(Potentilla anserina)、花苜蓿(Melissilus ruthenicus)、柴胡(Radix bupleuri)和美丽风毛菊(Saussurea pulchra)4种植物多度与两小型哺乳动物的分布显著相关。     

不同生境下云南蓝果树幼苗生长状况分析

对人工种植在关坪和景洪2个区域内的3个不同生境条件下的云南蓝果树幼苗生长情况比较得出：2011年,关坪区域林窗地块内幼苗的平均基径和平均苗高分别为1.5cm和1459cm,非林窗地块内则分别为1.0cm和101.3cm,而景洪区域幼苗的平均基径和平均苗高分别为1.9cm和121.5cm;2013年3个地块的平均基径和平均苗高分别为3.7cm和2996cm、2.3cm和1954cm、55cm和381.3cm。景洪区域的幼苗基径和苗高增长变化最为明显,其次为林窗地块,变化最小的是非林窗地块;2013年不同生境条件下云南蓝果树的生长差异极显著。     

基于综合视角的县域国土空间冲突测度与功能优化——以江西省宜黄县为例

[目的]测度国土空间冲突强度,分区探讨国土空间冲突管理和优化国土空间利用途径,为县域国土空间可持续开发利用提供新的思路。[方法]以江西省宜黄县为例,通过景观生态指数模型、可开发强度分析、用地现状与适宜性评价叠加3种方法,以“把握景观格局—明确开发强度—摸底适宜性—实现功能优化”综合视角为导向,构建综合视角下国土空间冲突测度模型,识别乡镇尺度下空间显著冲突与区域本位基底相耦合的综合冲突类型区,进而提出功能优化措施。[结果](1)2010—2020年宜黄县城镇化趋势扩大,生态空间的容纳度变低,国土空间主要表现为农业生产空间和生态空间向工矿生产空间和城镇生活空间转移。(2)2010—2020年宜黄县区域空间冲突强度加剧,不同时段和区域下空间冲突强度和分布情况差异显著,可控空间主要分布在南部,轻度和中度冲突在域内分布较为均匀,重度冲突主要分布在北部、中部和东部。(3)根据开发强度和冲突产生诱因,可将宜黄县乡镇划分为地形发展劣势区、城镇开发密集区和自然保护地集中区3类,作为空间功能优化的重点。(4)宜黄县乡镇尺度上空间冲突类型区分布存在差异性,表现为：农业空间与生态空间冲突>城镇空间与生态...     

Growth and interactions of arbuscular mycorrhizal fungi in soils from limestone and acid rock habitats

Arbuscular mycorrhizal (AM) development in different soil types, and the influence of AM fungal hyphae on their original soil were investigated. Plantago lanceolata, which can grow in soils of a very wide pH range, was grown in two closely related limestone soils and an acid soil from rock habitats. Plants were colonised by the indigenous AM fungal community. The use of compartmented systems allowed us to compare soil with and without mycorrhizal hyphae. Root colonisation of P. lanceolata was markedly higher in the limestone soils (30-60%) than in the acid soil (5-20%), both in the original habitat and in the experimental study. Growth of extraradical AM fungal hyphae was detected in the limestone soils, but not in the acid soil, using the signature fatty acid 16:1ω5 as biomass indicator. Analysis of signature fatty acids demonstrated an increased microbial biomass in the presence of AM fungal hyphae as judged for example from an increased amount of NLFA 16:0 with 30 nmol g⁻¹ in one of the limestone soils. Bacterial activity, but not soil phosphatase activity, was increased by around 25% in the presence of mycorrhizal hyphae in the first harvest of limestone soils. AM fungal hyphae can thus stimulate microorganisms. However, no effect of AM hyphae was observed on the soil pH or organic matter content in the limestone soils and the available P was not depleted.     

Do enchytraeid worms and habitat corridors facilitate the colonisation of habitat patches by soil microbes?

Due to their high abundance and ubiquitous existence, microbes are considered to be efficient colonisers of newly established habitats. To shed light on the dispersal mechanisms of soil microbes, a controlled microcosm experiment was established. In these microcosms, the dispersal of microbes from a source humus patch to originally sterile humus patches (embedded in a mineral soil matrix) was followed for 16 months, applying 16S and 18S ribosomal DNA-based PCR-DGGE molecular methods. Specifically, the role of enchytraeid worms and habitat (humus) corridors as possible facilitators of microbe dispersal was studied. The results showed that enchytraeid worms function efficiently as vectors for horizontal dispersal of saprophytic fungi in soil. Some of the fungi also proved to disperse through the corridors by vegetative growth, although this dispersal was inefficient as compared to dispersal with the enchytraeids. Virtually no saprophytic fungi were able to disperse through the mineral soil matrix in the absence of both enchytraeid worms and corridors. Unlike soil fungi, the dispersal of soil bacteria was not affected by any of the studied factors. The results of the present experiment provide direct evidence of the crucial role of soil fauna in aiding the horizontal dispersal of soil fungi. The role of enchytraeids as a functionally important species in boreal forest soils is further emphasized, since bringing microbes into contact with new resources is likely to enhance the rate of decomposition in soils.