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.     

昆明地区昭觉林蛙种群的繁殖研究

2004年10月～2006年12月观察了昆明地区昭觉林蛙(Rana chaochiaoensis)的产卵期、产卵量、孵化时间、孵化率以及蝌蚪期持续时间等.结果显示,昆明地区昭觉林蛙的产卵期为每年10～11月;产卵量平均为1 859.92粒·团-1;完成胚胎发育期全过程需8～9d;蝌蚪孵化率达99%以上;蝌蚪期持续时间为6个月,Ⅰ期蝌蚪发育历时130d,Ⅱ期蝌蚪发育需42d,从蝌蚪进入第Ⅲ期到观察超过50%的幼蛙登陆为10d左右.昭觉林蛙繁殖时对产卵场的选择条件为足够的水域面积、水温和丰富的水草.     

Habitat utilization and vertical movements of white marlin (Tetrapturus albidus) released from commercial and recreational fishing gears in the western North Atlantic Ocean: inferences from short duration pop-up archival satellite tags

Researchers have applied numerous techniques to improve billfish stock assessments, including habitat‐based models that incorporate behavioral and oceanographic parameters to standardize historical catch‐per‐unit‐effort time‐series data. These methods have allowed researchers to account for significant changes in the depths of pelagic longline (PLL) gear deployments over time. This study presents habitat‐use data recovered from high‐resolution 5‐ and 10‐day pop‐up satellite archival tags (PSATs) attached to 47 surviving white marlin released from commercial and recreational fishing gears offshore of the U.S. East Coast, the northern Caribbean, and Venezuela between 2002 and 2004. Data recovered from transmitting tags indicated that white marlin spent nearly half of their time associated with warm, near‐surface waters (<10 m). All fish displayed frequent short duration (mean: 39.8 min) vertical excursions from surface waters to depths averaging 51 m. Qualitative and multivariate classifications of data from completely transmitted movements of surviving white marlin revealed two major types of descents: one pattern was characterized by deep ‘V’‐shaped excursions of relatively short duration (mean: 23.4 min) while the other featured descents that were more broadly ‘U’‐shaped and confined to a specific depth range for an extended period of time (mean: 75.8 min). Based on the frequency, persistence, and patterns of these vertical movements, white marlin appear to direct a considerable proportion of foraging effort well below surface waters, a behavior that may account for relatively high catch rates of white marlin on some deep‐set PLL deployments.     

Priority habitats for the conservation of large river fish in the Ganges river basin

• 1. Three classes of habitat used by groups of fish species classified as conservation and management priorities were developed for the Gerua River (also known as the Girwa River, Karnali River) in the Ganges river basin. This river is large (mean annual discharge ca 1500 m³ s^?1, up to 900 m wide), surrounded by protected lands of India and Nepal, and upstream of major diversions and river alterations.
• 2. Fish and habitat sampling was conducted at 45 sites from 2000 to 2003. Data were analysed for 2172 fish of 14 species. Species and life stages found occupying a statistically distinct subset of the river habitats were grouped to identify classes of river habitat for conservation.
• 3. Most species and life‐stage groups specialized on specific habitat conditions revealed by multivariate analyses of variance and a principal component analysis. The most numerous and diverse group (six species, 15 life stages) was associated with deep depositional habitats with sandy substrate. Two species covering three life stages were primarily oriented to erosional habitat marked by fast current velocity with pebble and cobble substrate. A third group of three species of adults and juveniles were intermediate in habitat use.
• 4. River conservation for fish faunas should maintain both erosional and depositional channel habitats with depths, substrates, and current velocity inclusive of the ranges reported. The erosional and depositional nature of the key habitats requires that rivers be maintained with flows capable of channel‐forming functions.

Copyright © 2006 John Wiley & Sons, Ltd.     

Freshwater mussel assemblage structure in a regulated river in the Lower Mississippi River Alluvial Basin,USA

• 1. This paper documents a diverse, reproducing freshwater mussel community (20 species) in Lower Lake — an impounded, regulated portion of the Little Tallahatchie River below Sardis Dam in Panola Co., Mississippi, USA.
• 2. Despite being regulated and impounded, the lake has a heterogeneous array of habitats that differ markedly in mussel community attributes. Four distinct habitat types were identified based on current velocity and substrate characteristics, representing a gradient from habitats having lotic characteristics to lentic habitats. All four habitat types supported mussels, but habitats most resembling unimpounded, lotic situations (relatively higher current velocity and coarser substrate) had the highest mussel abundance and species density (10.1 mussels m^?2, 1.8 species m^?2, respectively). Lentic habitats (no flow, fine substrate) were characterized by lower abundance and species density (2.0 mussels m^?2, 0.8 species m^?2, respectively), but supported mussel assemblages distinctive from lotic habitats.
• 3. Evidence of strong recent recruitment was observed for most species in the lake and was observed in all four habitat types.
• 4. Although impounded and regulated, Lower Lake represents one of the few areas of stable large‐stream habitat in the region. The presence of a diverse, healthy mussel community in this highly modified habitat suggests that a large component of the regional mussel fauna is relatively resilient and adaptable and is limited primarily by the absence of stable river reaches. Management actions that increase stream stability are likely to result in expansion of the mussel fauna and restoration of a valuable component of ecosystem function in this region.

Published in 2006 by John Wiley & Sons, Ltd.     

Movements by wild brown trout in a boreal river: response to habitat and flow contrasts

Abstract  Radio transmitters were implanted in wild brown trout, Salmo trutta L., in the River Måna at low summer water flows ( n  = 18), higher flow in summer ( n  =   20), and variable, peaking flows in autumn ( n  =   20), and tracked two to four times day and night for 4–5 weeks. Individuals were caught and released in a 4-km uniformly channelised section, and in a 4-km natural diverse river section. Substantial individual variation in home range and total movement (924–85 818 m² and 295–7014 m) suggested flexibility to adapt to local environmental conditions. Fish were stationary most of the time (median movement 0 m), but some individuals undertook few and apparently sporadic longer movements, sometimes involving shifts in home range. No consistent diurnal pattern in movements was found. Trout in the uniform habitat section appeared to have larger home ranges and moved more than trout in the natural section. Differences were, however, not statistically significant in most comparisons, due to large individual variation. Similarly, larger home ranges and movements between trials related to higher flow were found, but differences were generally not significant. No consistent effects of sudden, extreme peaking flows on area use or movements by the brown trout were observed.     

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。     

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...     

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。     

典型草原建群种长芒草(Stipa bungeana)在中国的潜在分布范围预测及主要影响因子分析

以广泛分布在中国北方典型草原的建群种长芒草为研究对象,利用Maxent模型对长芒草在中国当前及未来气候变化下的潜在分布区进行预测并对主要影响其分布的环境变量进行分析,结果表明,采用受试者工作特征曲线(receiver operating characteristic curve,ROC)对模型精度进行检验所得到的训练数据与测试数据的受试者工作特征曲线面积(areaunder ROC curve,AUC)分别为0.962和0.950,表明模型预测结果可靠,当前中国长芒草高适宜性分布区主要有5个,分别为黄土高原分布区、泰山-沂蒙山分布区、横断山分布区、藏南谷地分布区及天山分布区。在RCP2.6(representative concentration pathways 2.6)和RCP8.5(representative concentration pathways 8.5)两种气候情景模式下预测得到的2070年长芒草最适宜的潜在分布区有逐渐缩小的趋势。Jackknife检验对主导环境变量的筛选结果显示,影响长芒草分布的主要环境变量有地形粗糙度指数(terrain roughness index,tri)、9月降水量(precipitation 09,prec09)、气候湿度指数(climatic moisture index,topowi)、2月最高温度(maximum temperature 02,tmax02)、12月降水量(precipitation 12,prec12)和12月平均温度(average temperature 12,tavg12)。结果可为气候变化背景下中国典型草原的可持续管理提供科学依据。