旅游干扰下水质对大鲵繁殖行为与繁殖力的影响

通过控制大鲵仿生态繁育池进水量模拟旅游干扰下的水质溶解氧特征,采用红外数字监控系统研究大鲵繁殖行为(产卵与护卵)及繁殖力(相对产卵量、受精率与孵化率)特点,分析它们与水质的关系,探讨旅游干扰导致的水质变化对大鲵繁殖行为及繁殖力的影响。结果表明: 与对照组相比,旅游干扰下大鲵的产卵行为与繁殖力未受到显著影响,但雄鲵护卵行为中的扇尾与搅动时间显著延长,以提高水中溶解氧浓度,满足大鲵胚胎发育需求;此外,旅游干扰下受精卵的孵化时间显著延长,但孵化率未受到显著影响。雄鲵护卵行为变化与受精卵孵化时间延长可能是大鲵对旅游干扰导致的水质变化的一种主动响应。     

中国大鲵的活动节律及繁殖行为描记

采用定时定点观察法,对仿生态条件下养殖的中国大鲵(Andrias davidianus)活动节律及繁殖行为进行了观察。结果表明,大鲵活动具有明显的昼夜节律变化,白天隐藏在洞穴中不活动,每天20:30时部分大鲵开始出洞活动,21:00时至次日凌晨1:00时为活动高峰期,1:00时后部分大鲵开始陆续回到洞穴,3:00时后又全部隐藏在洞穴中;大鲵的夜间活动随季节的变化而发生周期性变化,8～9月出洞活动的大鲵数量达到一年之中的最大值。大鲵尤其是雄鲵在繁殖季节表现出明显多样的繁殖行为:①推沙行为;②求偶行为,包括聚集、露头、巡视、追随、尾阴探究、亲吻、邀请和爬跨8种行为型;③冲凉行为;④护卵行为;⑤婚配行为。     

旅游干扰对张家界市大鲵饵料鱼及大鲵种群数量的影响

为了探究旅游干扰对国家Ⅱ级保护动物——中国大鲵(Andrias davidianus)种群数量及其饵料鱼种类、资源量的影响,对湖南省张家界市重度与轻度旅游干扰下大鲵栖息地的旅游干扰内容、饵料鱼的种类与渔获量、大鲵种群数量进行了同步调查与估算,并比较了旅游重度干扰区在旅游开发前后饵料鱼种类的差异,以及旅游重度与轻度干扰区饵料鱼种类与渔获量的差异。结果表明:在湖南省张家界市的大鲵栖息地共发现饵料鱼类4目10科22属25种;旅游重度干扰区现在饵料鱼的物种数大于旅游开发前,也大于轻度干扰区,但统计上无显著差别; Jaccard系数分析显示重度与轻度干扰区之间饵料鱼物种组成的相似性较小;与轻度干扰区相比,重度干扰区的渔获量较多,但大鲵种群数量较少。以上信息提示,在张家界市目前适度开发和管理模式下,旅游干扰对大鲵饵料鱼资源没有产生明显的负面影响,但重度干扰区可能由于游客活动带来的噪声增加或者洞穴数的减少等其他干扰因素使大鲵种群数量有所下降。     

高原鼠兔领域行为时间分配格局及其对风险环境适应的探讨

采用直接观察法测定了高原鼠兔地面、洞道活动时间及进、出洞频率。结果表明,在07：00-18：00,雄性和雌性高原鼠兔平均地面活动时间分别占总活动时间比例的87．09％和85．22％。地面活动时间具有明显的季节性,但两性个体间无显著的差异。繁殖早期,成年雌体地面活动时问显著高于繁殖后期,第2胎幼体地面活动时间显著低于第1胎幼体。不同年龄和性别的高原鼠兔进洞频率存在极显著差异,5月成年雌体进洞频率最高,而成年雄体在4月进洞频率最低。研究结果验证了捕食风险可制约鼠兔属动物领域活动时间分配,高风险环境能增加其利用洞道的时间及频率的特定假设。     

旅游干扰对张家界大鲵生境及水质的影响

为探明旅游干扰对中国大鲵生境及水质的影响,本研究实地调查了湖南省张家界市2014—2016年间不同旅游强度下的干扰情况,测定了大鲵栖息生境特点、水体理化及微生物指标.结果表明: 重度旅游干扰(每年>50万人次)显著增加了噪音、减少了大鲵洞穴数,降低了水中溶解氧含量,增加了总氮、总磷含量及微生物数量,尤其是大肠杆菌数量,导致大鲵栖息生境质量下降.但重度干扰区的水质仍然能够达到大鲵生长要求.根据国家地表Ⅱ类水大肠杆菌标准最高值(2000个·L^-1),计算得出游客数量理论临界值为每年2604.71万人次.通过控制游客数量与旅游设施面积,可降低旅游干扰强度,保护大鲵栖息生境,促进旅游开发与大鲵保护的协调发展.     

繁殖前期中国大鲵雄性成体的冲凉行为及其意义

为揭示和探讨中国大鲵(Andrias davidianus)繁殖前期的冲凉行为及其意义,在仿生态养殖环境条件下,采用定时定点观察法和全事件记录法,对雄性成鲵的冲凉行为过程及姿势进行了观察记录,并分析了冲凉行为与年龄、求偶行为、繁殖成功率之间的关系.繁殖前期雄性成鲵表现出冲凉行为,冲凉行为与求偶行为之间存在极显著的正相关,表现出求偶行为的6尾雄性成鲵有4尾成功参与了繁殖.冲凉行为可能促进了雄性成鲵精巢的发育,引发求偶行为,最终达到成功繁殖.     

黑腹果蝇昼夜活动节律及行为时间分配

采用试验室单管观察记录的方法,对3,4,5日龄野生型黑腹果蝇Drosophila melanogaster Meigenw1118成虫每日活动节律进行研究。试验将果蝇活动划分为强活动(飞行和爬行)、弱活动(梳理、觅食等原地发生的运动)和静息(身体不发生移动的休息)3种类型。强活动和弱活动之和为总运动。研究结果显示,野生型黑腹果蝇w1118的昼夜活动表现为明显的双峰模态,晨峰和晚峰分别处于开、关灯前后;雌、雄果蝇总体活动无差异,关灯(18:30)前后雌蝇活动稍强于雄蝇,开灯(6:30)前后则相反;果蝇强活动的节律与总运动基本一致,而弱活动节律不明显;静息节律为单峰模式,其高峰期位于夜间1:00~5:00;雌蝇的静息活动显著多于雄蝇(P<0·05)。     

圈养林麝夏季昼夜活动节律及时间分配

2011年、2012年的5～7月每月定期8天,每天00:00～24:00采用行为取样法在米亚罗养麝场观察记录54只林麝(15只成体雌麝,9只成体雄麝,10只亚成体雌麝,5只亚成体雄麝,15只幼麝)的行为。夏季共记录林麝83种行为,分成5种行为类型,即摄食、运动、休息、反刍及其他行为。夏季林麝具有明显的昼夜活动节律性,晨昏出现2个活动高峰期,分别为5:30～8:00和18:00～21:00,白昼活动率低于夜间。根据夏季林麝各行为累计时间和频率比较,表明圈养林麝的休息行为较高,尤其是幼体(65.38%±5.39%vs16.41h/d±1.29h/d),其次是摄食和运动行为。成体雌麝摄食行为比率高于成体雄麝、亚成体和幼体,这与夏季成体雌麝哺乳所需的能量较高有关。     

哺乳期圈养雌獐昼夜行为时间分配及活动节律

2014年7—8月,在浙江省富阳市獐养殖场采用瞬时扫描取样法对圈养条件下哺乳期雌獐昼夜行为时间分配及活动节律进行了调查研究。结果表明:1雌獐的日活动行为时间分配依次为卧息(59.01±2.93)%、走动(13.91±2.39)%、采食(10.60±0.74)%、梳理(7.76±1.10)%、反刍(2.84±0.66)%、站立(2.72±1.01)%、警戒(1.53±0.59)%、社会行为(1.26±0.54)%、排遗(0.36±0.22)%。2雌獐的昼间卧息时间极显著低于夜间(P<0.01),梳理时间显著低于夜间(P<0.05),而走动、采食、反刍、警戒和社会行为的时间极显著高于夜间(P<0.01),站立行为差异无统计学意义(P>0.05)。3一天中,雌獐的采食行为和反刍行为呈现双峰型的节律特征,走动、站立和梳理行为出现了3个高峰期,卧息和社会行为则呈多峰型,其中取食高峰后延迟1~2 h为反刍高峰。4卧息行为分别与采食行为和走动行为呈极显著的负相关关系,而采食行为与走动行为之间呈显著的正相关关系。总之,哺乳期圈养雌獐的日活动行为体现出明显的节律性,且大多数行为时间具有明显的昼夜差异。     

大鸨繁殖期活动时间预算和日节律

2000和2001年的4～7月连续两年,在内蒙古自治区科尔沁右翼前旗东南部的草原上,采用野外直接观察法对野生大鸨的活动时间预算和日节律进行了研究。结果表明,大鸨繁殖期的各种行为活动具有一定的时间分配,其时间预算存在着性别间的差异,同时随活动空间大小、食物条件以及繁殖阶段的不同而变化,在繁殖前期,大鸨的时间预算以取食、休息、行走、观察为主要行为,雄鸨和雌鸨的这4种行为分别占全部行为的87％和93％;到繁殖后期,雌鸨各种行为的时间和强度发生较大变化。大鸨在取食、休息和炫耀等行为上都存在不同程度的日节律,取食和炫耀出现两次高峰,中午大部分时间大鸨处于静栖休息状态。     

大兴安岭北坡黑嘴松鸡越冬期种群密度及夜栖地利用

为了更深入地了解黑嘴松鸡的种群密度及其夜栖地利用情况,以期为后续的黑嘴松鸡保护管理提供科学的理论参考,2017—2018年1—2月采用样线法、定点观察法、样方法、因子测量法、因子分析法、GPS定位等方法,对大兴安岭北坡越冬期黑嘴松鸡的种群密度及夜栖地特征进行了调查分析。分析结果表明:(1)大兴安岭北坡越冬期,黑嘴松鸡种群密度为(1.18—8.06)只/km~2,即每平方千米分布有黑嘴松鸡1—8只;(2)黑嘴松鸡夜栖卧迹长为(52.64±9.28) cm、宽为(26.55±6.91) cm、高为(17.11±3.78) cm;(3)黑嘴松鸡夜栖地利用包括2个尺度3个选择,即大生境尺度内夜栖生境类型选择和小生境尺度内夜栖区选择、夜栖微生境选择;(4)夜栖生境类型对以兴安落叶松为优势树种的针阔混交林具有绝对的选择性(100%);夜栖区对林缘雪地和林中乔木树下的偏好利用较高(75.00%);夜栖微生境选择通过隐蔽因子、应急逃逸因子、温度因子来判定,隐蔽因子包括乔木密度和干扰区距离,选择具有高密度乔木的、远离人为干扰区(约为4.5 km)的区域;应急逃逸因子包括海拔、卧迹头端开阔度、乔木距离,选择高海拔的、卧迹头端具有开阔度的、贴近乔木(小于1 m)的位置;温度因子包括卧迹雪深、卧迹头端方位角,选择保温效果显著的、适合体尺指标的背风点(东南出口)。     

Overexpression of cystathionine-γ-synthase enhances selenium volatilization in<Emphasis Type="Italic"> Brassica juncea</Emphasis>

Selenium (Se) can be assimilated and volatilized via the sulfate assimilation pathway. Cystathionine--synthase (CGS) is thought to catalyze the synthesis of Se-cystathionine from Se-cysteine, the first step in the conversion of Se-cysteine to volatile dimethylselenide. Here the hypothesis was tested that CGS is a rate-limiting enzyme for Se volatilization. Cystathionine--synthase from Arabidopsis thaliana (L.) Heynh. was overexpressed in Indian mustard [Brassica juncea (L.) Czern & Coss], and five transgenic CGS lines with up to 10-fold enhanced CGS levels were compared with wild-type Indian mustard with respect to Se volatilization, tolerance and accumulation. The CGS transgenics showed 2- to 3-fold higher Se volatilization rates than wild-type plants when supplied with selenate or selenite. Transgenic CGS plants contained 20–40% lower shoot Se levels and 50–70% lower root Se levels than the wild type when supplied with selenite. Furthermore, CGS seedlings were more tolerant to selenite than the wild type. There were no differences in Se accumulation or tolerance from selenate, in agreement with the earlier finding that selenate-to-selenite reduction is rate-limiting for selenate tolerance and accumulation. In conclusion, CGS appears to be a rate-limiting enzyme for Se volatilization. Overexpression of CGS offers a promising approach for the creation of plants with enhanced capacity to remove Se from contaminated sites in the form of low-toxic volatile dimethylselenide.Abbreviations CGS cystathionine--synthase - DMSe dimethylselenide - SeCys selenocysteine - WT wild type     

Exotic plant communities shift water-use timing in a shrub-steppe ecosystem

Semiarid areas in the US have realized extensive and persistent exotic plant invasions. Exotics may succeed in arid regions by extracting soil water at different times or from different depths than native plants, but little data is available to test this hypothesis. Using estimates of root mass, gravimetric soil water, soil-water potential, and stable isotope ratios in soil and plant tissues, we determined water-use patterns of exotic and native plant species in exotic- and native-dominated communities in Washington State, USA. Exotic and native communities both extracted 12 ± 2 cm of water from the top 120 cm of soil during the growing season. Exotic communities, however, shifted the timing of water use by extracting surface (0–15 cm) soil water early in the growing season (i.e., April to May) before native plants were active, and by extracting deep (0–120 cm) soil water late in the growing season (i.e., June to July) after natives had undergone seasonal senescence. We found that δ ¹⁸O values of water in exotic annuals (e.g., −11.8 ± 0.4 ‰ for Bromus tectorum L.) were similar to δ ¹⁸O values of surface soil water (e.g., −13.3 ± 1.4 ‰ at −15 cm) suggesting that transpiration by these species explained early season, surface water use in exotic communities. We also found that δ ¹⁸O values of water in taprooted exotics (e.g., −17.4 ± 0.3 ‰ for Centaurea diffusa Lam.) were similar to δ ¹⁸O values of deep soil water (e.g., −18.4 ± 0.1 ‰ at −120 cm) suggesting that transpiration by these species explained late season, deep water use. The combination of early-season, shallow water-use by exotic winter-actives and late-season, deep water-use by taprooted perennials potentially explains how exotic communities resist establishment of native species that largely extracted soil water only in the middle of the growing season (i.e., May to June). Early season irrigation or the planting of natives with established root systems may allow native plant restoration.     

Comparative study on the influence of dissolved oxygen control approaches on the microbial hyaluronic acid production of <Emphasis Type="Italic">Streptococcus zooepidemicus</Emphasis>

Three different dissolved oxygen (DO) control approaches were proposed to improve hyaluronic acid (HA) production: a three-stage agitation speed control approach, a two-stage DO control approach, and an oxygen vector perfluorodecalin (PFC) applied approach. In the three-stage agitation speed control approach, agitation speed was 200 rpm during 0–8 h, 400 rpm during 8–12 h, and 600 rpm during 12–20 h. In the two-stage DO control strategy, DO was controlled at above 10% during 0–8 h and at 5% during 8–20 h. In the PFC applied approach, PFC (3% v/v) was added at 8 h. HA production reached 5.5 g/L in the three-stage agitation speed control culture model, and 6.3 g/L in two-stage DO control culture model, and 6.6 g/L in the PFC applied culture model. Compared with the other two DO control approaches, the PFC applied approach had a lower shear stress and thus a higher HA production was achieved.     

Evaluation of the phenotypic characteristics of coliform bacteria recovered with two methods: the European Drinking Water Directive reference method and the Colilert 18/Quanti-Tray™ system

Summary The taxonomy of the species belonging to Enterobacteriaceae has undergone a series of revisions. As a consequence, the new classification has caused the analytical detection methods to be updated. According to the European Drinking Water Directive 98/83/CE coliforms/Escherichia coli have to be determined with the ISO 9308-1 reference method. Many technical drawbacks of the procedure as well as limitations regarding the recent taxonomy of coliforms have been pointed out by laboratories working in water quality control. In our investigation, water was analyzed in parallel with the reference method and the rapid Colilert 18/Quanti-Tray™ system. Phenotypic characteristics of isolates were recorded for the verification of the response of the two methods to the new taxonomic approach. Results obtained with the ISO standard confirmed the limitations of the test. In fact, in addition to difficulties linked to the readability of results, it failed to detect a significant proportion of coliforms and E. coli in water. Furthermore, it allowed the growth of microorganisms belonging to other groups. The Colilert 18/Quanti-Tray™ system detected a qualitatively and quantitatively higher number of target microorganisms. It also provided results in a shorter time, allowing the simultaneous detection of E. coli and coliforms with no further confirmation steps.     

Evidence for stabilization of aquaporin-2 folding mutants by N-linked glycosylation in endoplasmic reticulum

Aquaporin-2 (AQP2) is the vasopressin-sensitive water channel that regulates water reabsorption in the distal nephron collecting duct. Inherited AQP2 mutations that disrupt folding lead to nephrogenic diabetes insipidus (NDI) by targeting newly synthesized protein for degradation in the endoplasmic reticulum (ER). During synthesis, a subset of wild-type (WT) AQP2 is covalently modified by N-linked glycosylation at residue Asn123. To investigate the affect of glycosylation, we expressed WT AQP2 and four NDI-related mutants in Xenopus laevis oocytes and compared stability of glycosylated and nonglycosylated isoforms. In all constructs, 15–20% of newly synthesized AQP2 was covalently modified by N-linked glycosylation. At steady state, however, core glycosylated WT protein was nearly undetectable, whereas all mutants were found predominantly in the glycosylated form (60–70%). Pulse-chase metabolic labeling studies revealed that glycosylated isoforms of mutant AQP2 were significantly more stable than their nonglycosylated counterparts. For nonglycosylated isoforms, the half-life of WT AQP2 was significantly greater (>48 h) than that of mutant AQP2 (T126M 4.1 ± 1.0 h, A147T 4.2 ± 0.60 h, C181W 4.5 ± 0.50 h, R187C 6.8 ± 1.2 h). This is consistent with rapid turnover in the ER as previously reported. In contrast, the half-lives of mutant proteins containing N-linked glycans were similar to WT (25 h), indicating that differences in steady-state glycosylation profiles are caused by increased stability of glycosylated mutant proteins. These results suggest that addition of a single N-linked oligosaccharide moiety can partially compensate for ER folding defects induced by disease-related mutations. endoplasmic reticulum-associated degradation; nephrogenic diabetes insipidus; oocytes     

云南蒙自钳嘴鹳夜栖地利用及夜栖树选择

动物对夜栖地选择的灵活程度是其分布和扩散的重要因素之一。钳嘴鹳(Anastomus oscitans)为中国新分布种,要了解其扩散趋势,掌握其夜栖地需求至关重要。2015年11月至2018年7月在云南蒙自坝区,使用卫星跟踪技术对6只钳嘴鹳进行了夜栖地利用和夜栖树选择研究,结果表明:(1)钳嘴鹳可以在多种生境中夜栖,包括林地、沼泽、岛屿等。从群体水平上分析,钳嘴鹳主要夜栖于沼泽中,利用率为(51.19±12.34)%,其次为林地(31.55±11.34)%和岛屿(17.26±5.70)%;从个体水平上来看,不同钳嘴鹳的夜栖地利用方式差异较大,其中4只主要利用沼泽,而另外2只主要利用林地;(2)随机森林分析表明:影响钳嘴鹳夜栖树选择的首要因子为距觅食地距离,其次为树高、地径和最低枝高度,而人为干扰因子的影响较弱。综合来看,钳嘴鹳对夜栖地类型以及夜栖树均表现出了极强的适应性和可塑性,这可能是其能够快速扩散的重要原因之一。同时也表明夜栖树并不能成为一个有力的限制因子,钳嘴鹳有可能继续向国内的南方湿地区扩散。     

Response to human presence during nocturnal line transect surveys in fallow deer (<Emphasis Type="Italic">Dama dama</Emphasis>) and wild boar (<Emphasis Type="Italic">Sus scrofa</Emphasis>)

The use of line transect methodology and portable thermal imaging for ground survey of wildlife should require a good knowledge of the behavioural response of the animals to the presence of an observer, in order to take into account the potential bias in density estimate caused by deviation from the assumption that distances are recorded at the initial position. We used ten fallow deer and eight wild boar fitted with radiocollars to investigate animals’ response during simulated nocturnal line transect surveys, carried out in a Mediterranean plain forest. The experiment consisted in radiolocating a focal animal before and after an observer walked a transect nearby (<100 m). Each transect line was followed using a Global Positioning System (GPS) navigator. We carried out a total of 64 trials on fallow deer and 57 on wild boar. Results showed that despite most of the animals moved significantly in response to the observer (mean ± standard error, wild boar—95.3 ± 10.0 m; fallow deer—149.6 ± 14.2 m), the flying patterns were different in the two species: the reaction of fallow deer turned out to be more intense and directional with respect to that showed by wild boar. Although these results sound explorative, the experiment attempted here, for the first time, is relevant for an appropriate design of nocturnal distance-sampling surveys and gives information about potential bias arising from animal’s behavioural response. We believe that these first results may foster more in-deep analyses which are now made possible with the adoption of GPS technology for animal location.