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1.
上海郊区冬季红隼行为时间分配   总被引:8,自引:2,他引:6  
2003年11月~2004年2月采用随机个体、连续取样的方式,在上海郊区获取了越冬112只次红隼(Falco tinnunculus)123.33 h的行为数据,对红隼的时间行为分配模式进行了研究与分析。结果表明,冬季红隼白天活动时间大部分用于栖停(44.45%),其次为捕食(18.83%)、停落(12.17%)、飞行(9.98%)、滑翔(8.11%)、悬停(3.46%)、梳羽(1.70%)、戏耍和交互(1.32%)。栖停在早中晚占有较高的比例,而捕食在上午和下午分别具有一个高峰时段。红隼在1 d中具有两个活动高峰分别在上午(8∶00~10∶00)和下午(13∶00~15∶00)。通过对行为发生时间的相关性分析,发现活动高峰主要是由捕食行为及相关的飞行、悬停等行为组成。  相似文献   

2.
不同种群密度羊草生态场梯度及其变化特征   总被引:7,自引:2,他引:7  
通过对植物个体与种群生态场定位实验研究,提出了生态场梯度的概念,并给出了植物与羊草个体生态场梯度的模型,植物生态场的场梯度是,生态场中生态势沿任意方向的变化率。羊草个体生态场梯度同羊草种群密度相关。  相似文献   

3.
红喉雉鹑Tetraophasis obscurus是我国特有高山雉类,国家一级重点保护野生动物。为了解其生活习性及种群参数,2020—2021年在四川王朗国家级自然保护区采用红外相机技术、样线法和样点法对红喉雉鹑的日活动节律及其种群密度进行了调查。红喉雉鹑在保护区分布海拔为2 773~3 777 m,主要活动在3 200~3 400 m,常见于针叶林和针阔混交林,未在草甸生境中记录到;核密度函数绘制的日活动节律曲线表明,红喉雉鹑为昼行性动物,全年日活动曲线整体呈单峰模式,日活动强度在06∶00后快速升高,在08∶00—10∶00达到最高,之后快速降低至12∶00,其后缓慢下降,20∶00趋近于无;繁殖季和非繁殖季的日活动节律均呈双峰模式,但差异不显著(Δ=0.79),均以早晨最为活跃,非繁殖季比繁殖季的活动高峰推迟1~2 h;红外相机拍摄的群体平均大小为2.63只/群,样线调查的为3只/群,样线法和样点法估算的种群密度分别为7.60只/km2和5.42~6.18只/km2。本研究丰富了红喉雉鹑的野外生态学资料,为其保护管理和种群监测、评估提供...  相似文献   

4.
本文研究了我国特有、分布区极狭窄的一年生草本植物——杭州石荠苎(Mosla hangchowensis)种群的密度制约规律。结果表明:在生长季内,种群的死亡率与密度密切相关。种群的最适密度为200~1000株/m2左右。不同密度种群的平均株高、开花数等性状随时间的动态关系均符合“logistic”模型。高密度种群中60%左右的个体能完成生活史;低密度种群中80%以上的个体能完成生活史。种群密度较高制约杭州石荠苎的植株形态和繁殖投资。  相似文献   

5.
不同生境下入侵植物胜红蓟种群构件生物量分配特性   总被引:10,自引:2,他引:10  
周兵  闫小红  肖宜安  王宁  旷志强 《生态学报》2015,35(8):2602-2608
为探究入侵植物胜红蓟在种群构件水平上的生长特性,以更好地了解其整体的生存策略和入侵性,通过测定胜红蓟各构件的生物量、各构件生物量相关性、繁殖构件/营养构件比和根冠比,对Ⅰ房前屋后、Ⅱ菜园地、Ⅲ桔园和Ⅳ路边4种不同生境下的胜红蓟种群构件的生物量分配进行了分析研究。结果表明:不同生境下胜红蓟种群各构件的生物量既存在差异,又存在相同的趋势,即:茎生物量叶生物量根生物量花果生物量;生境Ⅱ胜红蓟总生物量、茎、叶和花果生物量均最大,生境Ⅳ的均最小,两者之间均存在显著差异(P0.05);不同生境中胜红蓟种群的根、茎、叶、花果生物量分配与其各构件生物量大小顺序并不一致,前者各生境间的差异小于后者各生境间的差异;4种生境下繁殖构件与营养构件生物量比大小顺序依次为ⅣⅢⅡⅠ,其值分别为0.069、0.061、0.050和0.042,根冠比大小顺序依次为ⅢⅠⅣⅡ,其值分别为0.211、0.179、0.154和0.090;胜红蓟植株株高与各构件及各构件之间存在极显著正相关(P0.01),株高与各构件的相关性中,株高与茎生物量的相关性最强,相关系数为0.525,各构件的相关性中,茎生物量与叶和花果生物量的相关性较强,其相关系数均大于0.900。胜红蓟种群在不同生境下各构件的生物量、繁殖构件/营养构件比和根冠比表现出的差异显示了其较强的表型可塑性和对异质环境的适应性,可能增强了其入侵性。不同生境下胜红蓟种群各构件生物量相同的趋势及生物量分配比间相对较小的差异显示了胜红蓟种群构件生物量分配模式的相对稳定性。胜红蓟种群各构件间的极显著相关性显示了其整体性的生存策略。  相似文献   

6.
沙地生境沙拐枣(Calligonum mongolicum)种群特征及其扩张   总被引:2,自引:0,他引:2  
沙拐枣(Calligonum mongolicum)是分布于我国北方荒漠、半荒漠的一种主要固沙植物,研究沙拐枣种群在沙地生境中的扩张对沙漠-绿洲过渡带的生态恢复和重建管理具有重要的实践意义.以巴丹吉林沙漠延伸带与河西走廊中部张临高绿洲过渡带为研究区域,采用踏查与样方调查相结合的方法对4种不同沙地生境(固定沙丘、半流动沙丘迎风坡、背风坡、丘间低地)中沙拐枣种群特征、繁殖规律、种群的扩张域和扩张速率进行了研究.结果表明:(1) 沙地生境中沙拐枣以有性繁殖为主.固定沙丘、半流动沙丘丘间低地、迎风坡和背风坡萌蘖苗密度占总密度的比值分别为35%、45%、2%、9%;实生苗密度比值分别为65%、55%、98%、91%.(2)不同生境中沙拐枣种群都为增长型种群;(3) 固定沙丘、半流动沙丘迎风坡、背风坡、丘间低地中,沙拐枣种群无性繁殖的扩张域和平均扩张速率分别为1~5m和0.67m/a、1~8m和0.64m/a、0~2m和0.15m/a、1~4m和0.41m/a.同时,3种生境中沙拐枣种群密度及其扩张速率都随着年龄的增长而下降.(4)沙拐枣种群在侵入新的生境过程中,开始于有性繁殖,利用无性繁殖拓展生存空间.  相似文献   

7.
研究表明,无视异绒螨种群密度与棉田连作年限之间呈正相关,与棉田海拔高度和水位之间呈负相关.露地棉田螨量明显高于地膜覆盖棉田.若螨在静水中的浮水时间可持续5.2h.成螨产卵的最适土壤含水量为12.5%.不同杀虫剂对幼螨杀伤力为溴氰菊酯喷雾>氧化乐果喷雾>三氯杀螨醇喷雾>氧化乐果缓释剂涂茎.因此,发展灌溉棉田、棉花适当连作、棉花生长期采取药剂涂茎治蚜对壮大无视异绒螨种群密度有重要作用.  相似文献   

8.
对海南岛尖峰岭林区海南重楼(Paris dunniana Lévl.)种群的生存状况进行了调查,并分析了其生存环境条件及种群结构特征与发展趋势.结果表明:在尖峰岭林区,只有35%的被调查沟谷生境存有海南重楼个体,大多数生境个体不足3株,平均种群密度仅为3.2 株*km-2,小群聚株间距大(3~30 m),种群联系程度低,呈孤立的分散状态.81%的调查个体株高低于100 cm,而低于80 cm的个体占75%以上; 87.5%的个体未开花; 平均根茎长10.5 cm, 变幅在 4~20 cm 之间. 植株小叶片数为 3~9, 只有 34.3% 的植株的小叶片数在 7 片或 7 片以上. 个体年龄 3~14 a,缺失3 a以下的幼年个体和10~11 a的个体,种群年龄结构呈缺失的不正常的"菱"型.综合分析表明,该种的生境退化严重,种群数量小,有性繁殖能力极弱,种群处于衰退状态,如不采取有效的保护措施将濒于灭绝.  相似文献   

9.
采用随机区组的试验方法, 着力于探索内蒙古荒漠草原3 种主要植物种群密度在不同生长季节随放牧强度变化而呈现出季节性的波动规律。研究对象主要是短花针茅(Stipa breviflora)、冷蒿(Artemisia frigida)和无芒隐子草(Cleistogenessongorica)。结果表明: 上述3 种主要植物种群总密度在放牧区均高于对照区; 短花针茅和无芒隐子草枝条总密度的变化趋势基本一致, 冷蒿枝条总密度总体逐月降低。整体分析而言, 放牧期间(6-9 月), 短花针茅、冷蒿和无芒隐子草枝条总密度的峰值均出现在HG(或MG), 说明放牧家畜的持续采食及践踏, 导致了植物种群株丛发生破碎而趋向小型化, HG(或MG)由母株破碎而产生的小株丛多, 故株丛总密度相应增加; 另外, 连续放牧致使大多数植株未能进行生殖生长即被采食, 从而促进了植物的营养繁殖和营养生长, 增加了种群密度。  相似文献   

10.
杭州石荠苎(Mosla hangchowensis)种群密度制约实验的统计分析   总被引:5,自引:0,他引:5  
本文研究了我国特有、分布区极狭窄的一年生草本植物——杭州石荠苎(Mosla hangchowensis)种群的密度制约规律。结果表明:在生长季内,种群的死亡率与密度密切相关。种群的最适密度为200~1000株/m2左右。不同密度种群的平均株高、开花数等性状随时间的动态关系均符合“logistic”模型。高密度种群中60%左右的个体能完成生活史;低密度种群中80%以上的个体能完成生活史。种群密度较高制约杭州石荠苎的植株形态和繁殖投资。  相似文献   

11.
ABSTRACT We used recent developments in theoretical population ecology to construct basic models of common loon (Gavia immer) demography and population dynamics. We parameterized these models using existing survival estimates and data from long-term monitoring of loon productivity and abundance. Our models include deterministic, 2-stage, density-independent matrix models, yielding population growth-rate estimates (λ) of 0.99 and 1.01 for intensively studied populations in our Wisconsin, USA, and New Hampshire, USA, study areas, respectively. Perturbation analysis of these models indicated that estimated growth rate is extremely sensitive to adult survival, as expected for this long-lived species. Also, we examined 20 years of count data for the 2 areas and evaluated support for a set of count-based models of population growth. We detected no temporal trend in Wisconsin, which would be consistent with fluctuation around an average equilibrium state but could also result from data limitations. For New Hampshire, the model set included varying formulations of density dependence and partitioning of stochasticity that were enabled by the annual sampling resolution. The best model for New Hampshire included density regulation of population growth and, along with the demographic analyses for both areas, provided insight into the possible importance of breeding habitat availability and the abundance of nonbreeding adults. Based on these results, we recommend that conservation organizations include nonbreeder abundance in common loon monitoring efforts and that additional emphasis be placed on identifying and managing human influences on adult loon survival.  相似文献   

12.
用多重PCR检测上海地区汉族人群9个STR基因座的多态性   总被引:11,自引:5,他引:11  
冯明亮  季芸  陆琼  马俊  稽月华  杨颖 《遗传》2002,24(4):403-406
利用多重PCR和四色荧光(5-FAM,JOE,NED和ROX)自动化检测技术调查上海地区汉族人群D3S1358、vWA、FGA、D8S1179、D21S11、D18S51、D5S818、D13S317、D7S820等9个STR基因座多态性分布并计算 该9个基因座的的基因频率(Pi)、个体鉴别力(DP)、无偏倚期望杂合性(H)、多态性信息含量(PIC)和非父排除概率(PE)。结果显示:9个STR基因座的基因型分布符合Hardy-Weinberg平衡,9个STR基因座中FGA基因座的DP值最高为0.9584,D8S1179的H值最高为0.9403,D18S51的PIC值最高为0.8560,D18S51的PE值最高为0.7391,9个STR基因座累积个体鉴别力(CDP)为0.9999996,累积非父排除能力(CPE)为0.99991。9个STR基因座适合作为中国人群的遗传标志,用于人类学、遗传疾病基因连锁分析、法医学亲子鉴定和个体识别等研究领域。  相似文献   

13.
关于睑虎属Goniurosaurus物种的研究主要集中在新种描述和系统进化等方面,对种群密度量化的研究较少。为研究海南吊罗山国家级自然保护区海南睑虎Goniurosaurus hainanensis种群的资源现状,2019年7—9月,在保护区内选取2个不同海拔梯度的样区(A样区551~688 m和B样区289~448 m),采用标记重捕法对该物种的种群密度进行了调查,并分别采用Schnabel法和Lincoln指数法进行种群密度估算。结果显示:采用Schnabel法估算的种群密度A样区为501只/hm2,B样区为1 999只/hm2;采用Lincoln指数法估算的种群密度A样区为583只/hm2,B样区为1 403只/hm2。结果表明:该物种的种群密度随海拔升高呈下降趋势。  相似文献   

14.
We examined population traits of yellow American eels from nine sites with similar habitat characteristics in each of four rivers in Maine, U.S.A. Migrating silver eels were also collected to compare sex ratio, age and size at migration among the four rivers. Population density and biomass were not significantly different among rivers with mean ranges of 8.4–21.8 eels 100m–2and 380–1485gm–2. Pairwise comparisons of the slopes of weight–length relationships of log transformed data (pooled data: intercept = –6.007, slope = 3.094, r2= 0.99, and n = 3116) revealed no significant differences among rivers. Length–age relationships (pooled data: intercept = 87.826, slope = 23.444, r2= 0.76, and n = 2325) also showed no statistically significant pairwise differences in slopes among rivers. In all rivers, sexual differentiation was complete by 270mm total length and age eleven. The sex ratios of migrating silver eels were not correlated with yellow eel sex ratios among the four rivers. Mean age at migration among the four rivers was significantly different for males only, with a range of 1.3years. Both sexes had some significant differences in size at migration among rivers, but the biological importance of the differences is tenuous (male range: 15mm, female range: 36mm). The yellow and silver eel population traits from these four rivers showed little variation when riverine habitat was isolated. Variations in traits appeared to be greater when eels from non-riverine habitats may have been present.  相似文献   

15.
应用主成分分析方法研究了阿拉善荒漠区白沙蒿飞播区土壤因子和白沙蒿生长状况,阐明了土壤性质的主要限制性因子和群落生长最主要的状况指标。结果表明:(1)各个土壤因子中,6月的土壤含水量是各土壤性质中最重要的因子,贡献率达到63.6%。土壤的分形维数也对土壤性质有重要作用,贡献率为8.8%。土壤中N、P、K含量的贡献率分别为5.4%、3.5%、3.5%,也是不容忽视的影响因子。(2)地上生物量最能反映植株的生长状况,其贡献率达到60.1%,而且和几种最主要的土壤因子都有极高的相关性。(3)对土壤因子的第一和第二主成分的排序结果显示,不同白沙蒿种群密度分为3个类型,而种群密度在2.1株/m2时,种群生长状况最佳。  相似文献   

16.
AimThe age-specific cancer patterns have changed significantly over the last few decades in urban Shanghai. Predicting the cancer incidence in an ageing population can help to anticipate future resource needs, evaluate primary prevention strategies, and inform further research studies.Materials and MethodsAnnual cancer cases and population data from 1988 to 2013 were collected from Shanghai Cancer Registry. A Bayesian age-period-cohort model was applied to project the future cancer incidence with demographical changes from 2014 to 2025.ResultsFrom 1988 through 2013, the urban population aged < 65 years decreased by 19.5%, while the population aged ≥ 65 years increased by 58.4%. In the same period, cancer cases increased by 66.0% (from 8315 to 13,806) and 88.6% (from 7448 to 14,048) in these two populations, respectively. From 2014–2025, the population size is expected to decrease by an additional 29.6% in people aged < 65 years, while it will increase by an additional 68.3% in people aged ≥ 65 years. Correspondingly, the model predicts an 87.5% and 143.4% increase in cancer cases for these two populations, respectively. The most pronounced increase was found in thyroid cancer in both sexes, followed by prostate, kidney, and colon cancer in men. In women, lung, kidney, and cervical cancer in women was expected to increase.ConclusionsThe number of cancer cases in urban Shanghai, especially in older people, is expected to significantly increase in the next decade. Particular strategies targeting the elderly are required to combat the cancers.  相似文献   

17.
Socially acquired information is widespread in the animal kingdom.Many individuals make behavioral decisions based on such socialinformation. In particular, individuals may decide to leaveor select their habitat based on social information. Few studieshave investigated the role of density-related information, apotential social cue about habitat quality in dispersal. Here,we tested for the possibility that the phenotype of intrudercommon lizards (Lacerta vivipara) may inadvertently carry informationabout their natal population density. We found that such informationuse is likely. The behavior of focal lizard was influenced bythe natal population density of the intruder it was interactingwith. This suggests that individuals may use the behavior ofothers to acquire appropriate information about surroundingsand to base spatial decisions on this information. Density-relatedinformation may then affect individual movement decisions andthus metapopulation dynamics.  相似文献   

18.
2006年12月~2007年2月,采用秩变换分析法对北京野鸭湖湿地自然保护区越冬灰鹤群的觅食栖息地选择规律进行了研究.在保护区18种土地利用类型中,灰鹤的觅食柄息地主要为玉米地、沼泽草甸、水库冰面和草场等4种.越冬灰鹤对玉米地的选择性最高,草场的选择性最低,说明北京地区越冬灰鹤对人类活动的依赖性很大.同时发现,烧荒、翻地等耕作方式会大大降低食物的可获得性,影响灰鹤的觅食效率.  相似文献   

19.
ABSTRACT We analyzed 53 years of banding and band recovery data along with estimates of harvest and population size to assess the role of harvest and density dependence in survival patterns and population dynamics of black brant (Branta bernicla nigricans) over the period 1950–2003. The black brant population has declined steadily since complete annual surveys began in 1960, so the role of harvest in the dynamics of this population is of considerable interest. We used Brownie models implemented in Program MARK to analyze banding data. In some models, we incorporated estimated sport harvest to test hypotheses about the role of harvest in survival. We also examined the hypothesis of density-dependent regulation of mortality by incorporating estimates of population size as a covariate into models of survival. For a shorter period (1985–2003), we also assessed hypotheses about the role of subsistence harvest and predation as sources of mortality. The best supported model of variation in survival and band recovery allowed survival rates to vary among 2 age classes (juv, second-yr plus ad brant) and the 2 sexes. We constrained survival probabilities to be constant within decades but allowed them to vary among decades. We also constrained band recovery rates to be constant within decades and to vary in parallel among age and sex classes. We were limited to decade-specific estimates of survival and band recovery rates because some years before 1984 lacked any banding, and banding in some other years was sparse. A competitive model constrained survival estimates to be the same for males and females. No model containing harvest or population size was competitive with models lacking these covariates (relative quasi-Akaike's Information Criterion adjusted for small sample size [βQAICc] > 13). In the best supported model, band recovery rates declined from 0.038 ± 0.0028 (F) and 0.040 ± 0.0031 (M) to 0.007 ± 0.0007 (F) and 0.007 ± 0.0007 (M) between the 1950s and 2000s, a clear indication that harvest rates declined over this period. Survival rates increased from 0.70 ± 0.02 and 0.71 ± 0.02 for adult males and females, respectively, in the 1950s to 0.88 ± 0.009 and 0.88 ± 0.01 for males and females, respectively, in the 1990s. Survival rates in the 1990s were among the highest estimated for brant and did not increase in the 2000s with additional reductions in sport harvest. For the shorter data set from 1985 to 2003, models containing covariates for either sport or subsistence harvest were less competitive than models lacking these terms (βQAICc > 3). For the best model containing subsistence harvest, the estimate of β linking subsistence harvest to survival, although imprecisely estimated, was near zero (β = −0.04 ± 0.30), consistent with the hypothesis that subsistence harvest had little impact on survival during this period. We conclude that while harvest likely influenced survival and population dynamics in earlier decades, it is most likely that continued population decline at least since 1990 is a result of low recruitment.  相似文献   

20.
This study examined population density, habitat and diet of Dasyatis marianae, a recently discovered species, in the reef complex of Maracajaú in Rio Grande do Norte state, Brazil. The highest concentration of D. marianae occurred in seagrass beds. Habitat use differed significantly between sex and age classes, with females and juveniles using areas other than reefs. Females utilized primarily seagrass beds and juveniles occurred mainly along the sandy bottom near the beach, highlighting the importance of protecting these areas. Dasyatis marianae diet was characterized primarily by crustaceans (91·9% index of relative importance, IRI), including shrimp, crabs and lobsters. The availability of prey in different habitat types influences occupation by D. marianae, but the prey selectivity of D. marianae, among other factors, may affect this relationship. Intense shrimp and lobster fishing in the region probably has an effect on preferred prey resources of this ray. Information on feeding habits of this species contributes to a better understanding of trophic dynamics and food webs, which is critical if ecosystem principles are to be integrated into fisheries management.  相似文献   

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