共查询到20条相似文献,搜索用时 31 毫秒
1.
Summary A field work with two plots of grid, a snap trap being set on each station spaced 5 m apart, was executed in the summer of
1968 to evaluate prebaiting in census trapping by comparing the result in one plot, prebaited for three days, with that in
the other not prebaited. Since the population was as high as some 230 per acre on the average in density and formed of the
vole,Microtus montebelli, alone, sufficient samples were gathered irrespective of the plot size as small as 50×50 m.
Owning to the circumstances, multiple collisions inflicted so intense influence on sampling especially in the prebaited plot
thatz-equation for census adjusted to the effect was well applicable to the data in either plot. In sampling, the fact that small
voles are apt to be caught later than large voles was statistically evidenced in either sex, and yet any proof that males
tend to be caught prior to females was not offered. It was ascertained in either plot that the daily catch was realized according
to the same rule through the whole period of trapping in both external belt and internal square within the plot; hence it
follows that no considerable immigration occurred.
One of the beneficial effects of prebaiting is sure to be that the probability of capture was markedly enhanced in the prebaited
plot, and a second is supposed, though inconclusively, to be that a good sampling could be executed consistently through the
census period giving rise to no inordinate catches perhaps due to heterogeneous sampling as was seen in earlier days in the
not prebaited plot. The supposition has derived from the condition that most of the whole population is trappable, which is
established by interrelation among population density, size of home range and trap spacing. It was suggested that the effect
of prebaiting should be evaluated from the view-point of the interrelation, because the basic utility of prebaiting consists
in that it may help to our utlimate purpose to estimate the whole population.
Contribution from JIBP-PT No. 55, carried out by the grant from the expenditure of Education Department to the specific study
on “Dynamics of Biosphere” 相似文献
2.
Ryo Tanaka 《Researches on Population Ecology》1972,13(2):127-151
Summary A substantial explication of the edge effect has been attempted by use of capture-recapture data for a vole population (Microtus montebelli), gathered intwo plots of 100×100 m or less during 12 days, cheked twice daily, in August 1970; the sample was quite sufficient
for the aim.
The edge effect as guessed by increased catch per trap is usually suspected to ensue from range-settlers in the outside boundary
strip of a plot and immigrants. But by a theoretical analysis I could attain a tentative conclusion that no increased catch
per trap will occur unless any invasion takes place. Then it follows that, apart from the effect of invasion, the role of
the adjoining outside settlers in the edge effect is essentially required to be studied in the light of knowledge on the truth
of size and shift in home range.
The variation in range behavior for 183 adult voles, captured 6 times or more, could be grouped into eight types, of which
the range-conservative type possessed 52% of the sample and the group of the type was justly utilized for giving averages
of range size. Besides, it was seen from the observed frequency of types that a considerable number of immigrants onto the
census plot were induced perhaps being allured by trap baits, but the majority of them proved to be assigned to the voles
that have their ranges inside the assessment line ofDice; the rest referable to effective immigrants was only a few (7%). I could perceive no reason such as disproves the idea ofDice’s additional boundary strip.
Viewed from maps of ingress shift of ranges, the effect of ingress must have been greater in the outer trap rows than in the
inner within the plot, so that it might well be called edge effect in general; such effect, however, is seen gradually diminishing
toward the center, and hence it is almost unlikely that one should find any clear-cut intra-plot assessment lines demarcating
such an inner square as quite free from edge effects.
Averages of observed range length and width (ORL and ORW), as reliable measures for the true range size, were determined from
the above group of specimens; as a result, the remarkable concept of elliptic range shape was established by regarding ORL
as long axis and ORW as short one, and, directly from these averages, the mean range sizes worked out at 0.04 for females
and 0.09 for males in acreage which proved to be surprisingly well agreeable with those of isotope-revealed ranges for voles
given byGodfrey (1954) andAmbrose (1969).
The catchability for marked voles (
) was estimated by the maximum likelihood method by use ofJolly’s formulae (1965), but that for unmarked ones (
) was made by the regression census formula; as a result it was shown that the population was clearly of π>p type and that the trap-experience that voles underwent one month or more ago can make them retain as high catchability as
π.
Contribution from JIBP-PT No. 110, carried out by the grant from the expenditure of Education Department to the specific study
on “Dynamics of Biosphere”. 相似文献
3.
Summary We have devised a census formula of curvilinear regression suitable for capture-recapture data of recapture-addicted populations
of the Japanese field vole (Microtus montebelli) obtained under a grid-plan with single-catch traps in order to estimate the whole population. The equation is founded on
the assumption that the trappable population on the initial day is increased in way of an exponential curve until it reaches
to the whole during one trapping period. The effect of trap-preoccupation by marked and multiple collisions is considered
in the formula. As a result of its application to field data of the vole, it has turned out that the equation is required
for the data gained under the trapping plan with trap spacing 10m, but not for those under the plan with spacing 5m, to estimate
the whole. A convenient method of analysis of the formula is offered here, but we have been yet unable to introduce assymptotic
variance of estimates.
Contributions from JIBP-PT No. 19, carried out by the grant from the expenditure of Education Department to the specific study
on “Dynamics of Biosphere”. 相似文献
4.
Summary A marking-and-recapture study of a population of overwintered adults ofEpilachna sparsa orientalis was carried out in a small farm containing potatoes and egg-plants. The experiment involved a single release and five recapture
samplings during May–June. The data were analysed byLeslie's re-recapture method. Assumption of randomness of sampling proved to be well satisfied.
Survival rate of the overwintered adult population was maintained as high as 90 per cent per week or more until early June,
and then it declined rapidly towards the end of June. Initially overwintered adults exclusively lived on potato plants, but
half of the population alive in mid June migrated to nearby egg-plants. Emigration out of the experimental field, however,
seemed not to be occurring.
Recapture data of marked individuals in the potato field indicate that majority of the individuals stayed within a radius
of 3 m, at least for 2 weeks. Similar data taken from another field also suggest that their mobility was far restricted as
compared with random movement within the field.
Some comparisons were made between the population behaviours of overwintered adults ofE. sparsa orientalis andE. vigintioctomaculata.
Contribution from the Entomological Laboratory, Kyoto University, No. 371. 相似文献
5.
Osamu Iwahashi 《Researches on Population Ecology》1977,19(1):87-98
Summary The sterile insect release method was applied to eradicate the melon fly,Dacus cucurbitae, from the 58.5 km2 island of Kume, in the Okinawa Islands group. Weekly releases of 1 to 1.5 million flies irradiated as pupae with 6–7 kR from
a cobalt-60 source did not decrease the wild melon fly population. Releases of 1.5–2 million pupae per week made from September,
1975 to January, 1976 decreased the percent egg-hatch of females caught on Kume Is., but did not decrease the percent infestation
significantly. The number of pupae released was increased from February, 1976 to accelerate the eradication process. When
the number of pupae released exceeded 3.5 million per week, a rapid increase in the ratio of marked (sterile) to unmarked
(wild) flies, a remarkable decrease in percent egg-hatch, and a decrease in percent infestation of fruits were observed. There
has been no sign of melon fly infestation in wild cucurbit fruits from October, 1976 to the present time (April, 1977), despite
the fact that more than 70,000 fruits were carefully examined. The eradication of the melon fly from Kume Is. was thus achieved
by April, 1977, after the release of 264 million sterile fly pupae. 相似文献
6.
B. F. J. Manly 《Researches on Population Ecology》1978,20(1):15-22
Summary The methods ofManly (1973),Manly (1975) andManly (1977) for estimating survival rates and relative survival rates from recapture data have been compared by computer simulation.
In the simulations batches of two types of animal were “released” at one point in “time” and recapture samples were taken
at “daily” intervals from then on. The various methods of estimation were then used to estimate, the daily survival rates
of type 1 and type 2 animals, and also the survival rate of the type 2 animals relative to the type 1 animals.
Simulation experiments were designed to examine (a) the bias in estimates, (b) the relative precision of different methods
of estimation, (c) the validity of confidence intervals for true parameter values, and (d) the effect on estimates of the
failure of certain assumptions. 相似文献
7.
William K. Reisen Farida Mahmood Tauheeda Parveen 《Researches on Population Ecology》1979,21(1):12-29
Summary A mark-release-recapture experiment to estimate population survivorship and absolute size was performed with wild-caughtAn. subpictus adults at the village of Khano-Harni, Lahore District, Punjab Province, Pakistan during September 1978, the end of the monsoon
rainy season, when temporal population abundance was maximized. Daily survival rate estimated from the recapture sequence
of marked adults was low, males=0.192 and females=0.343. Survivorship for females estimated by several vertical age-grading
procedures ranged from 0.347 to 0.628. Both stage- and age-specific life tables were calculated from vertical age-grading
data determined by the dilatation method. Female and male population size was estimated byBailey’s modification of theLincoln Index and was found to average 4478.4 and 6106.8, respectively. The bionomics, survivorship and population size ofAn. subpictus in the Lahore are indicated that this species was probably not important in the transmission of human malaria. 相似文献
8.
Summary Difficulty arises in applying marking-and-recapture methods to insects when the probability of recapture of marked individuals
is changed with advancing age, either due to detachment of the mark by moulting (in the case of larvae) or to changes in their
survival rate or their behaviour. A modification of the re-recapture method (Leslie
et al., 1953) has been devised to analyze the capture-recapture data of the 5th-instar larvae and adults ofNezara viridula L. Estimation of the rate of moulting to the adult stage is made with the aid of additional information on larval survival.
Migration rates of the larvae between the two halves of the census field is estimated byIwao's (1963) method. Through these analyses, the dynamic feature of the population during transition from the 5th instar to, adult
is revealed. Several problems involved in the application of marking-and-recapture methods to insect populations are discussed.
Contribution from the Entomological Laboratory, Kyoto University No. 392. 相似文献
9.
Ryo Tanaka 《Researches on Population Ecology》1966,8(2):93-101
Conclusion From a field study for the vole population (Clethrionomys rufocanus) in Hokkaido in the late summer of 1965, it has been proved that the range length may decrease from 25 to 18 m by the gross
along with the rise from 20 to 100 in the density level per acre, and hence that an appreciable discrepancy, due to underestimation,
may be produced in estimates of the exposed as compared to the whole population at an outbreaking density as high as 100 on
a plan with trap-spacing 10 m.
In consideration of this together with my preceding results, the strict terms that we may enough approximate the whole one
by estimating the exposed seem likely to be that the ratio of range radius to trap spacing, supposing a range is circular,
should be near 2 or more at either ordinary or outbreaking densities, to say in the concrete, that the trap spacing as close
as 5 m or so in grid is desirable with this vole, perhaps with most other voles. 相似文献
10.
Ottar N. Bj?rnstad Nils Chr Stenseth Takashi Saitoh Ole Chr Lingj?rde 《Researches on Population Ecology》1998,40(1):77-84
We study the regional transitions in dynamics of the gray-sided vole,Clethrionomys rufocanus, within Hokkaido, Japan. The data-set consists of 225 time series of varying length (most from 23 to 31 years long) collected
between 1962 and 1992 by the Forestry Agency of the Japanese Government. To see clearly how the periodic behavior changes
geographically, we estimate the spectral density functions of the growth rates of all populations using a log-spline method.
We subsequently apply functional data analysis to the estimated densities. The functional data analysis is, in this context,
analogous to a principal component analysis applied to curves. We plot the results of the analysis on the map of Hokkaido,
to reveal a clear transition from relatively stable populations in the southwest and west to populations undergoing 3–4 year
cycles in the northeast and east. The degree of seasonality in the vegetation and the rodent demography appear to be strongest
in the cyclic area. We briefly speculate that the destabilization of the rodent dynamics is linked to increased seasonalforcing
on the trophic interactions in which the gray-sided voles are involved. 相似文献
11.
Happiness and altruism within the extended family 总被引:1,自引:1,他引:0
We propose a direct measure of altruism between parents and adult children, using survey data on happiness from the German
Socio-Economic Panel for the years 2000–2004. The question of altruism within families has policy relevance, for example,
to understand whether public transfers crowd out private ones. Previous empirical evidence, based on observed transfer behavior,
has failed to establish a clear consensus. Using various cross section, panel data, and instrumental variable estimators,
we find a robust association between the happiness of parents and that of their adult children. A 1 standard deviation increase
in a child’s happiness is associated with the same increase in own happiness as that of a 20–45% increase in household income,
depending on specification. 相似文献
12.
Summary Untreated plot of ‘Kennebec’ and ‘Superior’ potatoes were sampled for Colorado potato beetle (CPB) at L'Assomption, Quebec,
in 1982, 1986 and 1987. Numbers of CPB larvae per stalk were counted on 74 occasions for sample sizes ranging from 50 to 200
stalks. Regression techniques were used to estimate the relationship between mean and cumulative proportion of stalks infected.
These were used to set up binomial sequential probability ratio test (SPRT) sampling plans for pest management decision making
with tally numbers (or tally thresholds, cutoff numbers) equal to 0,1,...10. A binomial scheme defined by tally number equal
to 4 is proposed for general use, and corresponding plans are given, with estimated operating characteristic and average sample
number curves. 相似文献
13.
Summary We studied settling-site selection and the resulting survival of two sessile scale insects,Ceroplastes rubens andC. ceriferus, in the citrus tree,Citrus unshiu, in central Japan.
C. rubens preferred 0-year-old twigs most as a settling-site; the density of nymphs settling on 0-year-old twigs was significantly
higher than those on ≥1-year-old twigs, and few nymphs settled on ≥3-year-old twigs. The mean survival rates from settling
until reproduction in the next year were significantly higher on more preferred twigs than on less preferred ones. InC. ceriferus, nymphs significantly preferred 1- and 2-year-old twigs to 0- and ≥3-year-old ones, and the mean survival rates on the more
preferred 1- and 2-year-old twigs were significantly higher than those on less preferred ≥3-year-old twigs. However, the survival
rate on less preferred 0-year-old twigs was slightly higher than those on 1- and 2-year-old ones. Thus, in both species of
scale, it was the preferred twigs which were more profitable sites for survival after settling, except for less preferred
0-year-old twigs forC. ceriferus.
In both scale species, most mortality was due to growth cessation, which is believed to be related to the twig quality as
a food source. Predators and parasitoids were minor mortality factors.
Both species showed constant survival rates until the density of settled nymphs exceeded double the “upper-limit” density,
whereupon they decreased drastically.
Nymphs ofC. rubens settling on twigs of high scale density showed a spacing-out distribution, those ofC. ceriferus did not. InC. rubens, an increase in preference for originally less profitable twigs at the later stage of the settling season was observed, but
not inC. ceriferus. Accordingly, individuals ofC. rubens showed a stronger tendency to avoid conspecifics than didC. ceriferus.
Although nymphs of the two scales clearly preferred more profitable sites, their settling-site selection did not agree with
the predictions from the ideal free distribution theory (Fretwell and Lucas, 1970). The discrepancies were (1) frequent settling
on less profitable sites at the early stage of the settling season, (2) insufficient utilization of the most profitable twigs,
and (3) virtually 100% mortality on overcrowded twigs under conditions where unoccupied profitable twigs still remained. These
discrepancies are thought due to the limited dispersal time of nymphs.
Contribution to the ecological studies of scale insects 2. 相似文献
14.
Summary The abundance of moths was monitored with light-traps in two sites in southern Bohemia, České Budějovice for 22 years and
in Černiš for 9 years. In these sites, that are vastly different in environmental stability and predictability, stability
of insect populations was studied. The amplitude of fluctuations in abundance of the insect populations, as measured by the
coefficient of variation (CV), varied a great deal between species so that there was a large overlap between the two sites.
Nevertheless there was a highly significant tendency for species at Černiš, the more stable site, to have smaller values of
CV, i.e., to be less fluctuating. Also in species co-occurring in the two sites, the CV at Černiš tended to be smaller. Trends
in abundance of individual species over time, both increases and decreases, were common in both sites and did not differ between
habitats. Environmental stability begets insect population stability in terms of the amplitude of the fluctuations, but trends
in time occur irrespective of stability of the habitat. 相似文献
15.
Richard J. Estes 《Social indicators research》2010,98(3):363-402
World social development has arrived at a critical turning point. Economically advanced nations have made significant progress
toward meeting the basic needs of their populations; however, the majority of developing countries have not. Problems of rapid
population growth, failing economies, famine, environmental devastation, majority-minority group conflicts, increasing militarization,
among others, are pushing many developing nations toward the brink of social chaos. This paper focuses on worldwide development
trends for the 40-year period 1970–2009. Particular attention is given to the disparities in development that exist between
the world’s “rich” and “poor” countries as well as the global forces that sustain these disparities. The paper also discusses
more recent positive trends occurring within the world’s “socially least developed countries” (SLDCs), especially those located
in Africa and Asia, in reducing poverty and in promoting improved quality of life for increasing numbers of their populations. 相似文献
16.
Use of the regression of mean crowding on mean density for estimating sample size and the transformation of data for the analysis of variance 总被引:8,自引:0,他引:8
Summary An approximate method for estimating the sample size in simple random sampling and a systematic way of transformation of sample
data are derived by using the parameters α and β of the regression of mean crowding on mean density in the spatial distribution
per quadrat of animal populations (Iwao, 1968). If the values of α and β have been known for the species concerned, the sample size needed to attain a desired precision
can be estimated by simply knowing the approximate level of mean density of the population to be sampled. Also, an appropriate
variance stabilizing transformation of sample data can be obtained by the method given here without restrictions on the distribution
pattern of the frequency counts.
Contribution from the Entomological Laboratory, Kyoto University No. 418.
Contributions from JIBP-PT No. 52. Aided in part by a grant from the Ministry of Education for the special project research,
‘Studies on the dynamic status of biosphere’. 相似文献
17.
Akio Hagihara 《Researches on Population Ecology》1999,41(2):151-159
A model for describing the competition–density (C-D) effect in self-thinning populations was developed on the basis of the
following three basic assumptions: (1) the growth of mean phytomass follows a general logistic equation; (2) final yield is
independent of initial population density; and (3) there exists a functional relationship between actual and initial population
densities at any given time. The resultant equation takes the same reciprocal form as the reciprocal equation of the C-D effect
derived from Shinozaki–Kira's theory (i.e., the logistic theory of the C-D effect), which deals with the density effect in
nonself-thinning populations. However, one of the two time-dependent coefficients is quite different in mathematical interpretation
between the two reciprocal equations. The reciprocal equation for self-thinning populations is essentially the same as the
reciprocal equation assumed in the derivation of the functional relationship between actual and initial population densities.
The establishment of the reciprocal equation is supported by the empirical facts that the reciprocal relationship between
mean phytomass and population density is discernible in not only nonself-thinning populations but also in self-thinning populations.
The present model is expected to systematically interpret underlying mechanisms between the C-D effect, which is observed
at a time constant among populations with various initial densities, and self-thinning, which is observed along a time continuum
in a given population.
Received: August 5, 1998 / Accepted: January 7, 1999 相似文献
18.
Bruce Headey 《Social indicators research》2010,97(1):7-21
Set-point theory is the main research paradigm in the field of subjective well-being (SWB). It has been extended and refined
for 30 years to take in new results. The central plank of the theory is that adult set-points do not change, except temporarily
in the face of major life events. There was always some ‘discordant data’, including evidence that some events are so tragic
(e.g. the death of one’s child) that people never regain their set-point. It was possible to dismiss these events as ‘exceptions’
and maintain the theory. However, several new findings are emerging, which cannot be dismissed as ‘exceptions’ and which appear
to require substantial revisions or replacement of set-point theory. Many of these findings are based on the German Socio-Economic
Panel Survey (SOEP 1984-), which provides the longest available time series on life satisfaction. Despite its centrality,
the concept of the set-point is often not precisely defined. In this paper three alternative working definitions are offered.
Depending on which definition is used, it is found that over 20 years 14–30% of German panel members recorded large and apparently
permanent changes in their set-points. Changes of this magnitude are not compatible with set-point theory as currently understood.
The challenge for SWB researchers now is to develop a theory which can account for change as well as stability. 相似文献
19.
Keizi Kiritani 《Researches on Population Ecology》1970,12(1):19-34
Summary Polymorphism in adult colour pattern ofNezara viridula is determined on the genetic basis. The basic colour patterns of adult are classified into four types, i. e. G, O, R and
F. No appreciable differences between these types were observed in respect to various physiological traits of nymphs and adults,
except that type G seems to be superior in reproductive ability but to be inferior in ability of surviving winters at least
to types R and F.
Inter-generation changes in percentage frequency of G type were examined from 1959 to 1967 covering more than 30 generations.
Percentage frequencies of G types prior to the severe winter of 1962–3 fluctuated greatly around a mean of 87.9%, while they
did to a lesser extent than before with a mean of 85.0% after the winter. Unexpected high percentages of G type were recorded
frequently in summer generations, viz. 1st and 2nd. On the other hand, the relative frequencies of G and O types decreased
after hibernation in contrast to the increases in those of F and R. This sort of changes in genetic composition related to
the winter of 1962–3 was observed in several populations segregated from each other.
This seasonal alternation of selective activity in the environments is considered to be responsible for retention of the polymorphism.
Alternative possible causes, i. e. difference in habitat preference, non-random mating and selective predation by predators
among polymorphs, may safely be rejected as irrelevant to the mechanism in maintaining polymorphism.
The polymorphism of this insect seems to be in a transient state rather than balanced one contributing little to population
regulation, but the persistence ofN. viridula in the periphery range may be assisted by retention of the polymorphism. 相似文献
20.
Summary A simple mathematical model was proposed to describe the dynamics of a food-consumer system. The model was based on the Logistic
Theory and consisted of Eqs. (4), (5) and (6). The model was divided into the following three cases for further analyss; i)
without food supply except at the initial time, ii) with continuous food supply at a constant rate, and iii) with food supply
at varying rates. Only the first model was dealth with in this paper.
The assumptions of the model 1 are that a definite amount of food is given only once at the initial time and only the feeding
by animals is responsible for the decrease of food, and that the rate of decrease is proportional to the amount of animals.
It is also assumed that the growth of animal population is represented by the logistic curve, and that the upper limit of
the population is proportional to the amount of food at that time. For simplicity the parameters of basic differential equations
are assumed to be constant throughout the time course.
Analytical solutions of this non-linear model were given by Eqs. (8), (9), (10) and (11). The properties of time course of
the food amount and consumer population were discussed from the mathematical and biological points of view. The method of
the estimation of the three constants λ,b, andc from the experimental data was also suggested.
Since we had no available data for animal populations, we applied the model, regarding reserve substance asx and new plant body asy, to the data of the initial growth of Azuki bean plant in the dark.
This model is very simple, but it may be useful for analyzing the behavior of food-consumer system. And it may give some clue
to the analysis of the more complex systems. 相似文献